Morphogenesis in Plants: Modeling the Shoot Apical Meristem, and Possible Applications

NASA Technical Reports Server (NTRS)

Mjolsness, Eric; Gor, Victoria; Meyerowitz, Elliot; Mann, Tobias

1998-01-01

A key determinant of overall morphogenesis in flowering plants such as Arabidopsis thaliana is the shoot apical meristem (growing tip of a shoot). Gene regulation networks can be used to model this system. We exhibit a very preliminary two-dimensional model including gene regulation and intercellular signaling, but omitting cell division and dynamical geometry. The model can be trained to have three stable regions of gene expression corresponding to the central zone, peripheral zone, and rib meristem. We also discuss a space-engineering motivation for studying and controlling the morphogenesis of plants using such computational models.

A novel ALS-associated variant in UBQLN4 regulates motor axon morphogenesis.

PubMed

Edens, Brittany M; Yan, Jianhua; Miller, Nimrod; Deng, Han-Xiang; Siddique, Teepu; Ma, Yongchao C

2017-05-02

The etiological underpinnings of amyotrophic lateral sclerosis (ALS) are complex and incompletely understood, although contributions to pathogenesis by regulators of proteolytic pathways have become increasingly apparent. Here, we present a novel variant in UBQLN4 that is associated with ALS and show that its expression compromises motor axon morphogenesis in mouse motor neurons and in zebrafish. We further demonstrate that the ALS-associated UBQLN4 variant impairs proteasomal function, and identify the Wnt signaling pathway effector beta-catenin as a UBQLN4 substrate. Inhibition of beta-catenin function rescues the UBQLN4 variant-induced motor axon phenotypes. These findings provide a strong link between the regulation of axonal morphogenesis and a new ALS-associated gene variant mediated by protein degradation pathways.

Role of an expansin-like molecule in Dictyostelium morphogenesis and regulation of its gene expression by the signal transducer and activator of transcription protein Dd-STATa.

PubMed

Ogasawara, Shun; Shimada, Nao; Kawata, Takefumi

2009-02-01

Expansins are proteins involved in plant morphogenesis, exerting their effects on cellulose to extend cell walls. Dictyostelium is an organism that possesses expansin-like molecules, but their functions are not known. In this study, we analyzed the expL7 (expansin-like 7) gene, which has been identified as a putative target of Dd-STATa, a Dictyostelium homolog of the metazoan signal transducer and activator of transcription (STAT) proteins. Promoter fragments of the expL7 were fused to a lacZ reporter and the expression patterns determined. As expected from the behavior of the endogenous expL7 gene, the expL7/lacZ fusion gene was downregulated in Dd-STATa null slugs. In the parental strain, the expL7 promoter was activated in the anterior tip region. Mutational analysis of the promoter identified a sequence that was necessary for expression in tip cells. In addition, an activator sequence for pstAB cells was identified. These sequences act in combination with the repressor region to prevent ectopic expL7 expression in the prespore and prestalk regions of the slug and culminant. Although the expL7 null mutant showed no phenotypic change, the expL7 overexpressor showed aberrant stalk formation. These results indicate that the expansin-like molecule is important for morphogenesis in Dictyostelium.

Epithelial Markers aSMA, Krt14, and Krt19 Unveil Elements of Murine Lacrimal Gland Morphogenesis and Maturation.

PubMed

Kuony, Alison; Michon, Frederic

2017-01-01

As an element of the lacrimal apparatus, the lacrimal gland (LG) produces the aqueous part of the tear film, which protects the eye surface. Therefore, a defective LG can lead to serious eyesight impairment. Up to now, little is known about LG morphogenesis and subsequent maturation. In this study, we delineated elements of the cellular and molecular events involved in LG formation by using three epithelial markers, namely aSMA, Krt14, and Krt19. While aSMA marked a restricted epithelial population of the terminal end buds (TEBs) in the forming LG, Krt14 was found in the whole embryonic LG epithelial basal cell layer. Interestingly, Krt19 specifically labeled the presumptive ductal domain and subsequently, the luminal cell layer. By combining these markers, the Fucci reporter mouse strain and genetic fate mapping of the Krt14 + population, we demonstrated that LG epithelium expansion is fuelled by a patterned cell proliferation, and to a lesser extent by epithelial reorganization and possible mesenchymal-to-epithelial transition. We pointed out that this epithelial reorganization, which is associated with apoptosis, regulated the lumen formation. Finally, we showed that the inhibition of Notch signaling prevented the ductal identity from setting, and led to a LG covered by ectopic TEBs. Taken together our results bring a deeper understanding on LG morphogenesis, epithelial domain identity, and organ expansion.

Epithelial Markers aSMA, Krt14, and Krt19 Unveil Elements of Murine Lacrimal Gland Morphogenesis and Maturation

PubMed Central

Kuony, Alison; Michon, Frederic

2017-01-01

As an element of the lacrimal apparatus, the lacrimal gland (LG) produces the aqueous part of the tear film, which protects the eye surface. Therefore, a defective LG can lead to serious eyesight impairment. Up to now, little is known about LG morphogenesis and subsequent maturation. In this study, we delineated elements of the cellular and molecular events involved in LG formation by using three epithelial markers, namely aSMA, Krt14, and Krt19. While aSMA marked a restricted epithelial population of the terminal end buds (TEBs) in the forming LG, Krt14 was found in the whole embryonic LG epithelial basal cell layer. Interestingly, Krt19 specifically labeled the presumptive ductal domain and subsequently, the luminal cell layer. By combining these markers, the Fucci reporter mouse strain and genetic fate mapping of the Krt14+ population, we demonstrated that LG epithelium expansion is fuelled by a patterned cell proliferation, and to a lesser extent by epithelial reorganization and possible mesenchymal-to-epithelial transition. We pointed out that this epithelial reorganization, which is associated with apoptosis, regulated the lumen formation. Finally, we showed that the inhibition of Notch signaling prevented the ductal identity from setting, and led to a LG covered by ectopic TEBs. Taken together our results bring a deeper understanding on LG morphogenesis, epithelial domain identity, and organ expansion. PMID:29033846

The Ron Receptor Tyrosine Kinase Negatively Regulates Mammary Gland Branching Morphogenesis

PubMed Central

Meyer, Sara E.; Zinser, Glendon M.; Stuart, William D.; Pathrose, Peterson; Waltz, Susan E.

2009-01-01

The Ron receptor tyrosine kinase is expressed in normal breast tissue and is overexpressed in approximately 50% of human breast cancers. Despite the recent studies on Ron in breast cancer, nothing is known about the importance of this protein during breast development. To investigate the functional significance of Ron in the normal mammary gland, we compared mammary gland development in wild-type mice to mice containing a targeted ablation of the tyrosine kinase (TK) signaling domain of Ron (TK−/−). Mammary glands from RonTK−/− mice exhibited accelerated pubertal development including significantly increased ductal extension and branching morphogenesis. While circulating levels of estrogen, progesterone, and overall rates of epithelial cell turnover were unchanged, significant increases in phosphorylated MAPK, which predominantly localized to the epithelium, were associated with increased branching morphogenesis. Additionally, purified RonTK−/− epithelial cells cultured ex vivo exhibited enhanced branching morphogenesis, which was reduced upon MAPK inhibition. Microarray analysis of pubertal RonTK−/− glands revealed 393 genes temporally impacted by Ron expression with significant changes observed in signaling networks regulating development, morphogenesis, differentiation, cell motility, and adhesion. In total, these studies represent the first evidence of a role for the Ron receptor tyrosine kinase as a critical negative regulator of mammary development. PMID:19576199

Differentiated roles for MreB-actin isologues and autolytic enzymes in Bacillus subtilis morphogenesis.

PubMed

Domínguez-Cuevas, Patricia; Porcelli, Ida; Daniel, Richard A; Errington, Jeff

2013-09-01

Cell morphogenesis in most bacteria is governed by spatiotemporal growth regulation of the peptidoglycan cell wall layer. Much is known about peptidoglycan synthesis but regulation of its turnover by hydrolytic enzymes is much less well understood. Bacillus subtilis has a multitude of such enzymes. Two of the best characterized are CwlO and LytE: cells lacking both enzymes have a lethal block in cell elongation. Here we show that activity of CwlO is regulated by an ABC transporter, FtsEX, which is required for cell elongation, unlike cell division as in Escherichia coli. Actin-like MreB proteins are thought to play a key role in orchestrating cell wall morphogenesis. B. subtilis has three MreB isologues with partially differentiated functions. We now show that the three MreB isologues have differential roles in regulation of the CwlO and LytE systems and that autolysins control different aspects of cell morphogenesis. The results add major autolytic activities to the growing list of functions controlled by MreB isologues in bacteria and provide new insights into the different specialized functions of essential cell wall autolysins. © 2013 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.

The ureteric bud epithelium: morphogenesis and roles in metanephric kidney patterning.

PubMed

Nagalakshmi, Vidya K; Yu, Jing

2015-03-01

The mammalian metanephric kidney is composed of two epithelial components, the collecting duct system and the nephron epithelium, that differentiate from two different tissues -the ureteric bud epithelium and the nephron progenitors, respectively-of intermediate mesoderm origin. The collecting duct system is generated through reiterative ureteric bud branching morphogenesis, whereas the nephron epithelium is formed in a process termed nephrogenesis, which is initiated with the mesenchymal-epithelial transition of the nephron progenitors. Ureteric bud branching morphogenesis is regulated by nephron progenitors, and in return, the ureteric bud epithelium regulates nephrogenesis. The metanephric kidney is physiologically divided along the corticomedullary axis into subcompartments that are enriched with specific segments of these two epithelial structures. Here, we provide an overview of the major molecular and cellular processes underlying the morphogenesis and patterning of the ureteric bud epithelium and its roles in the cortico-medullary patterning of the metanephric kidney. © 2015 Wiley Periodicals, Inc.

SEPT9_v1 Functions in Breast Cancer Cell Division

DTIC Science & Technology

2012-01-01

the regulation and function of septin filaments, and define new mechanisms regulating important cellular functions. BODY: 1). Study the effects...ciliogenesis. However, mechanisms for retaining these proteins and lipids in the primary cilia are not clear. We directly tested the presence of a diffusion...polarity and morphogenesis;  Defined mechanisms involving the roles of septins and microtubules in vesicle trafficking and epithelial morphogenesis

MarvelD3 regulates the c-Jun N-terminal kinase pathway during eye development in Xenopus

PubMed Central

Vacca, Barbara; Sanchez-Heras, Elena; Steed, Emily; Balda, Maria S.; Ohnuma, Shin-Ichi; Sasai, Noriaki; Mayor, Roberto

2016-01-01

ABSTRACT Ocular morphogenesis requires several signalling pathways controlling the expression of transcription factors and cell-cycle regulators. However, despite a well-known mechanism, the dialogue between those signals and factors remains to be unveiled. Here, we identify a requirement for MarvelD3, a tight junction transmembrane protein, in eye morphogenesis in Xenopus. MarvelD3 depletion led to an abnormally pigmented eye or even an eye-less phenotype, which was rescued by ectopic MarvelD3 expression. Altering MarvelD3 expression led to deregulated expression of cell-cycle regulators and transcription factors required for eye development. The eye phenotype was rescued by increased c-Jun terminal Kinase activation. Thus, MarvelD3 links tight junctions and modulation of the JNK pathway to eye morphogenesis. PMID:27870636

A novel ALS-associated variant in UBQLN4 regulates motor axon morphogenesis

PubMed Central

Edens, Brittany M; Yan, Jianhua; Miller, Nimrod; Deng, Han-Xiang; Siddique, Teepu; Ma, Yongchao C

2017-01-01

The etiological underpinnings of amyotrophic lateral sclerosis (ALS) are complex and incompletely understood, although contributions to pathogenesis by regulators of proteolytic pathways have become increasingly apparent. Here, we present a novel variant in UBQLN4 that is associated with ALS and show that its expression compromises motor axon morphogenesis in mouse motor neurons and in zebrafish. We further demonstrate that the ALS-associated UBQLN4 variant impairs proteasomal function, and identify the Wnt signaling pathway effector beta-catenin as a UBQLN4 substrate. Inhibition of beta-catenin function rescues the UBQLN4 variant-induced motor axon phenotypes. These findings provide a strong link between the regulation of axonal morphogenesis and a new ALS-associated gene variant mediated by protein degradation pathways. DOI: http://dx.doi.org/10.7554/eLife.25453.001 PMID:28463112

Atypical chemokine receptor ACKR2 controls branching morphogenesis in the developing mammary gland

PubMed Central

Hewit, Kay D.; Pallas, Kenneth J.; Cairney, Claire J.; Lee, Kit M.; Hansell, Christopher A.; Stein, Torsten

2017-01-01

Macrophages are important regulators of branching morphogenesis during development and postnatally in the mammary gland. Regulation of macrophage dynamics during these processes can therefore have a profound impact on development. We demonstrate here that the developing mammary gland expresses high levels of inflammatory CC-chemokines, which are essential in vivo regulators of macrophage migration. We further demonstrate that the atypical chemokine receptor ACKR2, which scavenges inflammatory CC-chemokines, is differentially expressed during mammary gland development. We have previously shown that ACKR2 regulates macrophage dynamics during lymphatic vessel development. Here, we extend these observations to reveal a novel role for ACKR2 in regulating the postnatal development of the mammary gland. Specifically, we show that Ackr2−/− mice display precocious mammary gland development. This is associated with increased macrophage recruitment to the developing gland and increased density of the ductal epithelial network. These data demonstrate that ACKR2 is an important regulator of branching morphogenesis in diverse biological contexts and provide the first evidence of a role for chemokines and their receptors in postnatal development processes. PMID:27888192

DRhoGEF2 and Diaphanous Regulate Contractile Force during Segmental Groove Morphogenesis in the Drosophila Embryo

PubMed Central

Mulinari, Shai; Barmchi, Mojgan Padash

2008-01-01

Morphogenesis of the Drosophila embryo is associated with dynamic rearrangement of the actin cytoskeleton mediated by small GTPases of the Rho family. These GTPases act as molecular switches that are activated by guanine nucleotide exchange factors. One of these factors, DRhoGEF2, plays an important role in the constriction of actin filaments during pole cell formation, blastoderm cellularization, and invagination of the germ layers. Here, we show that DRhoGEF2 is equally important during morphogenesis of segmental grooves, which become apparent as tissue infoldings during mid-embryogenesis. Examination of DRhoGEF2-mutant embryos indicates a role for DRhoGEF2 in the control of cell shape changes during segmental groove morphogenesis. Overexpression of DRhoGEF2 in the ectoderm recruits myosin II to the cell cortex and induces cell contraction. At groove regression, DRhoGEF2 is enriched in cells posterior to the groove that undergo apical constriction, indicating that groove regression is an active process. We further show that the Formin Diaphanous is required for groove formation and strengthens cell junctions in the epidermis. Morphological analysis suggests that Dia regulates cell shape in a way distinct from DRhoGEF2. We propose that DRhoGEF2 acts through Rho1 to regulate acto-myosin constriction but not Diaphanous-mediated F-actin nucleation during segmental groove morphogenesis. PMID:18287521

SACE_0012, a TetR-family transcriptional regulator, affects the morphogenesis of Saccharopolyspora erythraea.

PubMed

Yin, Xiaojuan; Xu, Xinqiang; Wu, Hang; Yuan, Li; Huang, Xunduan; Zhang, Buchang

2013-12-01

Saccharopolyspora erythraea, a mycelium-forming actinomycete, produces a clinically important antibiotic erythromycin. Extensive investigations have provided insights into erythromycin biosynthesis in S. erythraea, but knowledge of its morphogenesis remains limited. By gene inactivation and complementation strategies, the TetR-family transcriptional regulator SACE_0012 was identified to be a negative regulator of mycelium formation of S. erythraea A226. Detected by quantitative real-time PCR, the relative transcription of SACE_7115, the amfC homolog for an aerial mycelium formation protein, was dramatically increased in SACE_0012 mutant, whereas erythromycin biosynthetic gene eryA, a pleiotropic regulatory gene bldD, and the genes SACE_2141, SACE_6464, SACE_6040, that are the homologs to the sporulation regulators WhiA, WhiB, WhiG, were not differentially expressed. SACE_0012 disruption could not restore its defect of aerial development in bldD mutant, and also did not further accelerate the mycelium formation in the mutant of SACE_7040 gene, that was previously identified to be a morphogenesis repressor. Furthermore, the transcriptional level of SACE_0012 had not markedly changed in bldD and SACE_7040 mutant over A226. Taken together, these results suggest that SACE_0012 is a negative regulator of S. erythraea morphogenesis by mainly increasing the transcription of amfC gene, independently of the BldD regulatory system.

Functional Role of the microRNA-200 Family in Breast Morphogenesis and Neoplasia

PubMed Central

Hilmarsdottir, Bylgja; Briem, Eirikur; Bergthorsson, Jon Thor; Magnusson, Magnus Karl; Gudjonsson, Thorarinn

2014-01-01

Branching epithelial morphogenesis is closely linked to epithelial-to-mesenchymal transition (EMT), a process important in normal development and cancer progression. The miR-200 family regulates epithelial morphogenesis and EMT through a negative feedback loop with the ZEB1 and ZEB2 transcription factors. miR-200 inhibits expression of ZEB1/2 mRNA, which in turn can down-regulate the miR-200 family that further results in down-regulation of E-cadherin and induction of a mesenchymal phenotype. Recent studies show that the expression of miR-200 genes is high during late pregnancy and lactation, thereby indicating that these miRs are important for breast epithelial morphogenesis and differentiation. miR-200 genes have been studied intensively in relation to breast cancer progression and metastasis, where it has been shown that miR-200 members are down-regulated in basal-like breast cancer where the EMT phenotype is prominent. There is growing evidence that the miR-200 family is up-regulated in distal breast metastasis indicating that these miRs are important for colonization of metastatic breast cancer cells through induction of mesenchymal to epithelial transition. The dual role of miR-200 in primary and metastatic breast cancer is of interest for future therapeutic interventions, making it important to understand its role and interacting partners in more detail. PMID:25216122

The arabidopsis IDD14, IDD15, and IDD16 cooperatively regulate lateral organ morphogenesis and gravitropism by promoting auxin biosynthesis and transport.

PubMed

Cui, Dayong; Zhao, Jingbo; Jing, Yanjun; Fan, Mingzhu; Liu, Jing; Wang, Zhicai; Xin, Wei; Hu, Yuxin

2013-01-01

The plant hormone auxin plays a critical role in regulating various aspects of plant growth and development, and the spatial accumulation of auxin within organs, which is primarily attributable to local auxin biosynthesis and polar transport, is largely responsible for lateral organ morphogenesis and the establishment of plant architecture. Here, we show that three Arabidopsis INDETERMINATE DOMAIN (IDD) transcription factors, IDD14, IDD15, and IDD16, cooperatively regulate auxin biosynthesis and transport and thus aerial organ morphogenesis and gravitropic responses. Gain-of-function of each IDD gene in Arabidopsis results in small and transversally down-curled leaves, whereas loss-of-function of these IDD genes causes pleiotropic phenotypes in aerial organs and defects in gravitropic responses, including altered leaf shape, flower development, fertility, and plant architecture. Further analyses indicate that these IDD genes regulate spatial auxin accumulation by directly targeting YUCCA5 (YUC5), TRYPTOPHAN AMINOTRANSFERASE of ARABIDOPSIS1 (TAA1), and PIN-FORMED1 (PIN1) to promote auxin biosynthesis and transport. Moreover, mutation or ectopic expression of YUC suppresses the organ morphogenic phenotype and partially restores the gravitropic responses in gain- or loss-of-function idd mutants, respectively. Taken together, our results reveal that a subfamily of IDD transcription factors plays a critical role in the regulation of spatial auxin accumulation, thereby controlling organ morphogenesis and gravitropic responses in plants.

Stress and strain provide positional and directional cues in development.

PubMed

Bozorg, Behruz; Krupinski, Pawel; Jönsson, Henrik

2014-01-01

The morphogenesis of organs necessarily involves mechanical interactions and changes in mechanical properties of a tissue. A long standing question is how such changes are directed on a cellular scale while being coordinated at a tissular scale. Growing evidence suggests that mechanical cues are participating in the control of growth and morphogenesis during development. We introduce a mechanical model that represents the deposition of cellulose fibers in primary plant walls. In the model both the degree of material anisotropy and the anisotropy direction are regulated by stress anisotropy. We show that the finite element shell model and the simpler triangular biquadratic springs approach provide equally adequate descriptions of cell mechanics in tissue pressure simulations of the epidermis. In a growing organ, where circumferentially organized fibers act as a main controller of longitudinal growth, we show that the fiber direction can be correlated with both the maximal stress direction and the direction orthogonal to the maximal strain direction. However, when dynamic updates of the fiber direction are introduced, the mechanical stress provides a robust directional cue for the circumferential organization of the fibers, whereas the orthogonal to maximal strain model leads to an unstable situation where the fibers reorient longitudinally. Our investigation of the more complex shape and growth patterns in the shoot apical meristem where new organs are initiated shows that a stress based feedback on fiber directions is capable of reproducing the main features of in vivo cellulose fiber directions, deformations and material properties in different regions of the shoot. In particular, we show that this purely mechanical model can create radially distinct regions such that cells expand slowly and isotropically in the central zone while cells at the periphery expand more quickly and in the radial direction, which is a well established growth pattern in the meristem.

Anabaena sp. strain PCC 7120 conR contains a LytR-CpsA-Psr domain, is developmentally regulated, and is essential for diazotrophic growth and heterocyst morphogenesis.

PubMed

Mella-Herrera, Rodrigo A; Neunuebel, M Ramona; Golden, James W

2011-03-01

The conR (all0187) gene of the filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 is predicted to be part of a family of proteins that contain the LytR-CpsA-Psr domain associated with septum formation and cell wall maintenance. The conR gene was originally misannotated as a transcription regulator. Northern RNA blot analysis showed that conR expression was upregulated 8 h after nitrogen step-down. Fluorescence microscopy of a P(conR)-gfp reporter strain revealed increased GFP fluorescence in proheterocysts and heterocysts beginning 9 h after nitrogen step-down. Insertional inactivation of conR caused a septum-formation defect of vegetative cells grown in nitrate-containing medium. In nitrate-free medium, mutant filaments formed abnormally long heterocysts and were defective for diazotrophic growth. Septum formation between heterocysts and adjacent vegetative cells was abnormal, often with one or both poles of the heterocysts appearing partially open. In a conR mutant, expression of nifH was delayed after nitrogen step-down and nitrogenase activity was approximately 70 % of wild-type activity, indicating that heterocysts of the conR mutant strain are partially functional. We hypothesize that the diazotrophic growth defect is caused by an inability of the heterocysts to transport fixed nitrogen to the neighbouring vegetative cells.

ΔNp63 is an ectodermal gatekeeper of epidermal morphogenesis

PubMed Central

Shalom-Feuerstein, R; Lena, A M; Zhou, H; De La Forest Divonne, S; Van Bokhoven, H; Candi, E; Melino, G; Aberdam, D

2011-01-01

p63, a member of p53 family, has a significant role in the development and maintenance of stratified epithelia. However, a persistent dispute remained over the last decade concerning the interpretation of the severe failure of p63-null embryos to develop stratified epithelia. In this study, by investigating both p63-deficient strains, we demonstrated that p63-deficient epithelia failed to develop beyond ectodermal stage as they remained a monolayer of non-proliferating cells expressing K8/K18. Importantly, in the absence of p63, corneal-epithelial commitment (which occurs at embryonic day 12.5 of mouse embryogenesis) was hampered 3 weeks before corneal stem cell renewal (that begins at P14). Taken together, these data illustrate the significant role of p63 in epithelial embryogenesis, before and independently of other functions of p63 in adult stem cells regulation. Transcriptome analysis of laser captured-embryonic tissues confirmed the latter hypothesis, demonstrating that a battery of epidermal genes that were activated in wild-type epidermis remained silent in p63-null tissues. Furthermore, we defined a subset of novel bona fide p63-induced genes orchestrating first epidermal stratification and a subset of p63-repressed mesodermal-specific genes. These data highlight the earliest recognized action of ΔNp63 in the induction epidermal morphogenesis at E11.5. In the absence of p63, a mesodermal program is activated while epidermal morphogenesis does not initiate. PMID:21127502

Regulation of tight junction assembly and epithelial morphogenesis by the heat shock protein Apg-2

PubMed Central

Aijaz, Saima; Sanchez-Heras, Elena; Balda, Maria S; Matter, Karl

2007-01-01

Background Tight junctions are required for epithelial barrier formation and participate in the regulation of signalling mechanisms that control proliferation and differentiation. ZO-1 is a tight junction-associated adaptor protein that regulates gene expression, junction assembly and epithelial morphogenesis. We have previously demonstrated that the heat shock protein Apg-2 binds ZO-1 and thereby regulates its role in cell proliferation. Here, we addressed the question whether Apg-2 is also important for junction formation and epithelial morphogenesis. Results We demonstrate that depletion of Apg-2 by RNAi in MDCK cells did not prevent formation of functional tight junctions. Similar to ZO-1, however, reduced expression of Apg-2 retarded de novo junction assembly if analysed in a Ca-switch model. Formation of functional junctions, as monitored by measuring transepithelial electrical resistance, and recruitment of tight and adherens junction markers were retarded. If cultured in three dimensional extracellular matrix gels, Apg-2 depleted cells, as previously shown for ZO-1 depleted cells, did not form hollow polarised cysts but poorly organised, irregular structures. Conclusion Our data indicate that Apg-2 regulates junction assembly and is required for normal epithelial morphogenesis in a three-dimensional culture system, suggesting that Apg-2 is an important regulator of epithelial differentiation. As the observed phenotypes are similar to those previously described for ZO-1 depleted cells and depletion of Apg-2 retards junctional recruitment of ZO-1, regulation of ZO-1 is likely to be an important functional role for Apg-2 during epithelial differentiation. PMID:18028534

Regulation of tight junction assembly and epithelial morphogenesis by the heat shock protein Apg-2.

PubMed

Aijaz, Saima; Sanchez-Heras, Elena; Balda, Maria S; Matter, Karl

2007-11-20

Tight junctions are required for epithelial barrier formation and participate in the regulation of signalling mechanisms that control proliferation and differentiation. ZO-1 is a tight junction-associated adaptor protein that regulates gene expression, junction assembly and epithelial morphogenesis. We have previously demonstrated that the heat shock protein Apg-2 binds ZO-1 and thereby regulates its role in cell proliferation. Here, we addressed the question whether Apg-2 is also important for junction formation and epithelial morphogenesis. We demonstrate that depletion of Apg-2 by RNAi in MDCK cells did not prevent formation of functional tight junctions. Similar to ZO-1, however, reduced expression of Apg-2 retarded de novo junction assembly if analysed in a Ca-switch model. Formation of functional junctions, as monitored by measuring transepithelial electrical resistance, and recruitment of tight and adherens junction markers were retarded. If cultured in three dimensional extracellular matrix gels, Apg-2 depleted cells, as previously shown for ZO-1 depleted cells, did not form hollow polarised cysts but poorly organised, irregular structures. Our data indicate that Apg-2 regulates junction assembly and is required for normal epithelial morphogenesis in a three-dimensional culture system, suggesting that Apg-2 is an important regulator of epithelial differentiation. As the observed phenotypes are similar to those previously described for ZO-1 depleted cells and depletion of Apg-2 retards junctional recruitment of ZO-1, regulation of ZO-1 is likely to be an important functional role for Apg-2 during epithelial differentiation.

The TCP4 transcription factor regulates trichome cell differentiation by directly activating GLABROUS INFLORESCENCE STEMS in Arabidopsis thaliana.

PubMed

Vadde, Batthula Vijaya Lakshmi; Challa, Krishna Reddy; Nath, Utpal

2018-01-01

Trichomes are the first cell type to be differentiated during the morphogenesis of leaf epidermis and serve as an ideal model to study cellular differentiation. Many genes involved in the patterning and differentiation of trichome cells have been studied over the past decades, and the majority of these genes encode transcription factors that specifically regulate epidermal cell development. However, the upstream regulators of these genes that link early leaf morphogenesis with cell type differentiation are less studied. The TCP proteins are the plant-specific transcription factors involved in regulating diverse aspects of plant development including lateral organ morphogenesis by modulating cell proliferation and differentiation. Here, we show that the miR319-regulated class II TCP proteins, notably TCP4, suppress trichome branching in Arabidopsis leaves and inflorescence stem by direct transcriptional activation of GLABROUS INFLORESCENCE STEMS (GIS), a known negative regulator of trichome branching. The trichome branch number is increased in plants with reduced TCP activity and decreased in the gain-of-function lines of TCP4. Biochemical analyses show that TCP4 binds to the upstream regulatory region of GIS and activates its expression. Detailed genetic analyses show that GIS and TCP4 work in same pathway and GIS function is required for TCP4-mediated regulation of trichome differentiation. Taken together, these results identify a role for the class II TCP genes in trichome differentiation, thus providing a connection between organ morphogenesis and cellular differentiation. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Morphogenesis checkpoint kinase Swe1 is the executor of lipolysis-dependent cell-cycle progression

PubMed Central

Chauhan, Neha; Visram, Myriam; Cristobal-Sarramian, Alvaro; Sarkleti, Florian

2015-01-01

Cell growth and division requires the precise duplication of cellular DNA content but also of membranes and organelles. Knowledge about the cell-cycle–dependent regulation of membrane and storage lipid homeostasis is only rudimentary. Previous work from our laboratory has shown that the breakdown of triacylglycerols (TGs) is regulated in a cell-cycle–dependent manner, by activation of the Tgl4 lipase by the major cyclin-dependent kinase Cdc28. The lipases Tgl3 and Tgl4 are required for efficient cell-cycle progression during the G1/S (Gap1/replication phase) transition, at the onset of bud formation, and their absence leads to a cell-cycle delay. We now show that defective lipolysis activates the Swe1 morphogenesis checkpoint kinase that halts cell-cycle progression by phosphorylation of Cdc28 at tyrosine residue 19. Saturated long-chain fatty acids and phytosphingosine supplementation rescue the cell-cycle delay in the Tgl3/Tgl4 lipase-deficient strain, suggesting that Swe1 activity responds to imbalanced sphingolipid metabolism, in the absence of TG degradation. We propose a model by which TG-derived sphingolipids are required to activate the protein phosphatase 2A (PP2ACdc55) to attenuate Swe1 phosphorylation and its inhibitory effect on Cdc28 at the G1/S transition of the cell cycle. PMID:25713391

Morphogenesis checkpoint kinase Swe1 is the executor of lipolysis-dependent cell-cycle progression.

PubMed

Chauhan, Neha; Visram, Myriam; Cristobal-Sarramian, Alvaro; Sarkleti, Florian; Kohlwein, Sepp D

2015-03-10

Cell growth and division requires the precise duplication of cellular DNA content but also of membranes and organelles. Knowledge about the cell-cycle-dependent regulation of membrane and storage lipid homeostasis is only rudimentary. Previous work from our laboratory has shown that the breakdown of triacylglycerols (TGs) is regulated in a cell-cycle-dependent manner, by activation of the Tgl4 lipase by the major cyclin-dependent kinase Cdc28. The lipases Tgl3 and Tgl4 are required for efficient cell-cycle progression during the G1/S (Gap1/replication phase) transition, at the onset of bud formation, and their absence leads to a cell-cycle delay. We now show that defective lipolysis activates the Swe1 morphogenesis checkpoint kinase that halts cell-cycle progression by phosphorylation of Cdc28 at tyrosine residue 19. Saturated long-chain fatty acids and phytosphingosine supplementation rescue the cell-cycle delay in the Tgl3/Tgl4 lipase-deficient strain, suggesting that Swe1 activity responds to imbalanced sphingolipid metabolism, in the absence of TG degradation. We propose a model by which TG-derived sphingolipids are required to activate the protein phosphatase 2A (PP2A(Cdc55)) to attenuate Swe1 phosphorylation and its inhibitory effect on Cdc28 at the G1/S transition of the cell cycle.

Mis-expression of grainyhead-like transcription factors in zebrafish leads to defects in enveloping layer (EVL) integrity, cellular morphogenesis and axial extension.

PubMed

Miles, Lee B; Darido, Charbel; Kaslin, Jan; Heath, Joan K; Jane, Stephen M; Dworkin, Sebastian

2017-12-14

The grainyhead-like (grhl) transcription factors play crucial roles in craniofacial development, epithelial morphogenesis, neural tube closure, and dorso-ventral patterning. By utilising the zebrafish to differentially regulate expression of family members grhl2b and grhl3, we show that both genes regulate epithelial migration, particularly convergence-extension (CE) type movements, during embryogenesis. Genetic deletion of grhl3 via CRISPR/Cas9 results in failure to complete epiboly and pre-gastrulation embryonic rupture, whereas morpholino (MO)-mediated knockdown of grhl3 signalling leads to aberrant neural tube morphogenesis at the midbrain-hindbrain boundary (MHB), a phenotype likely due to a compromised overlying enveloping layer (EVL). Further disruptions of grhl3-dependent pathways (through co-knockdown of grhl3 with target genes spec1 and arhgef19) confirm significant MHB morphogenesis and neural tube closure defects. Concomitant MO-mediated disruption of both grhl2b and grhl3 results in further extensive CE-like defects in body patterning, notochord and somite morphogenesis. Interestingly, over-expression of either grhl2b or grhl3 also leads to numerous phenotypes consistent with disrupted cellular migration during gastrulation, including embryo dorsalisation, axial duplication and impaired neural tube migration leading to cyclopia. Taken together, our study ascribes novel roles to the Grhl family in the context of embryonic development and morphogenesis.

Pak4 Is Required during Epithelial Polarity Remodeling through Regulating AJ Stability and Bazooka Retention at the ZA

PubMed Central

Walther, Rhian F.; Nunes de Almeida, Francisca; Vlassaks, Evi; Burden, Jemima J.; Pichaud, Franck

2016-01-01

Summary The ability of epithelial cells to assemble into sheets relies on their zonula adherens (ZA), a circumferential belt of adherens junction (AJ) material, which can be remodeled during development to shape organs. Here, we show that during ZA remodeling in a model neuroepithelial cell, the Cdc42 effector P21-activated kinase 4 (Pak4/Mbt) regulates AJ morphogenesis and stability through β-catenin (β-cat/Arm) phosphorylation. We find that β-catenin phosphorylation by Mbt, and associated AJ morphogenesis, is needed for the retention of the apical determinant Par3/Bazooka at the remodeling ZA. Importantly, this retention mechanism functions together with Par1-dependent lateral exclusion of Par3/Bazooka to regulate apical membrane differentiation. Our results reveal an important functional link between Pak4, AJ material morphogenesis, and polarity remodeling during organogenesis downstream of Par3. PMID:27052178

Identification of SACE_7040, a member of TetR family related to the morphological differentiation of Saccharopolyspora erythraea.

PubMed

Han, Shu; Song, Ping; Ren, Ting; Huang, Xunduan; Cao, Cheng; Zhang, Buchang

2011-08-01

SACE_7040 is presumed to be a member of the TetR family of transcriptional regulators in Saccharopolyspora erythraea, but its biological function is unknown. It was shown that the SACE_7040 gene knockout mutant formed aerial mycelium earlier than its original strain, and this phenotype could be restored by complementation of a single copy of SACE_7040 gene, demonstrating that SACE_7040 is an important regulator of the morphological differentiation of Sac. erythraea. When SACE_7040 gene was disrupted in the bldD mutant, we intriguingly found that the defect in aerial development exhibited by the bldD mutant could be overcome, suggesting a crosstalk between SACE_7040 and BldD in Sac. erythraea morphogenesis. These findings provide novel insights toward the Sac. erythraea developmental biology.

Mechanism of the synergistic effect of amiodarone and fluconazole in Candida albicans.

PubMed

Gamarra, Soledad; Rocha, Elousa Maria F; Zhang, Yong-Qiang; Park, Steven; Rao, Rajini; Perlin, David S

2010-05-01

The antiarrhythmic drug amiodarone has been found to have fungicidal activity. In Saccharomyces cerevisiae, its antifungal activity is mediated by calcium overload stress, which leads to a rapid nuclear accumulation of the calcineurin-regulated transcription factor CRZ1. In addition, low doses of amiodarone have been reported to be synergistic with fluconazole in fluconazole-resistant Candida albicans. To establish its mechanism of toxicity in C. albicans, we used expression profiling of key pathway genes to examine cellular responses to amiodarone alone and in combination with fluconazole. Gene expression profiling of 59 genes was done in five C. albicans strains (three fluconazole-susceptible strains and two fluconazole-resistant strains) after amiodarone and/or fluconazole exposure. Of the 59 genes, 27 analyzed showed a significant change (>2-fold) in expression levels after amiodarone exposure. The up- or downregulated genes included genes involved in Ca(2+) homeostasis, cell wall synthesis, vacuolar/lysosomal transport, diverse pathway regulation, stress response, and pseudohyphal morphogenesis. As expected, fluconazole induces an increase in ergosterol pathway genes expression levels. The combination treatment significantly dampened the transcriptional response to either drug, suggesting that synergism was due to an inhibition of compensatory response pathways. This dampening resulted in a decrease in total ergosterol levels and decreased pseudohyphal formation, a finding consistent with decreased virulence in a murine candidiasis model.

Identification and Expression of Acetylcholinesterase in Octopus vulgaris Arm Development and Regeneration: a Conserved Role for ACHE?

PubMed

Fossati, Sara Maria; Candiani, Simona; Nödl, Marie-Therese; Maragliano, Luca; Pennuto, Maria; Domingues, Pedro; Benfenati, Fabio; Pestarino, Mario; Zullo, Letizia

2015-08-01

Acetylcholinesterase (ACHE) is a glycoprotein with a key role in terminating synaptic transmission in cholinergic neurons of both vertebrates and invertebrates. ACHE is also involved in the regulation of cell growth and morphogenesis during embryogenesis and regeneration acting through its non-cholinergic sites. The mollusk Octopus vulgaris provides a powerful model for investigating the mechanisms underlying tissue morphogenesis due to its high regenerative power. Here, we performed a comparative investigation of arm morphogenesis during adult arm regeneration and embryonic arm development which may provide insights on the conserved ACHE pathways. In this study, we cloned and characterized O. vulgaris ACHE, finding a single highly conserved ACHE hydrophobic variant, characterized by prototypical catalytic sites and a putative consensus region for a glycosylphosphatidylinositol (GPI)-anchor attachment at the COOH-terminus. We then show that its expression level is correlated to the stage of morphogenesis in both adult and embryonic arm. In particular, ACHE is localized in typical neuronal sites when adult-like arm morphology is established and in differentiating cell locations during the early stages of arm morphogenesis. This possibility is also supported by the presence in the ACHE sequence and model structure of both cholinergic and non-cholinergic sites. This study provides insights into ACHE conserved roles during processes of arm morphogenesis. In addition, our modeling study offers a solid basis for predicting the interaction of the ACHE domains with pharmacological blockers for in vivo investigations. We therefore suggest ACHE as a target for the regulation of tissue morphogenesis.

Rap1, Canoe and Mbt cooperate with Bazooka to promote zonula adherens assembly in the fly photoreceptor

PubMed Central

Burki, Mubarik

2018-01-01

ABSTRACT In Drosophila epithelial cells, apical exclusion of Bazooka (the Drosophila Par3 protein) defines the position of the zonula adherens (ZA), which demarcates the apical and lateral membrane and allows cells to assemble into sheets. Here, we show that the small GTPase Rap1, its effector Canoe (Cno) and the Cdc42 effector kinase Mushroom bodies tiny (Mbt), converge in regulating epithelial morphogenesis by coupling stabilization of the adherens junction (AJ) protein E-Cadherin and Bazooka retention at the ZA. Furthermore, our results show that the localization of Rap1, Cno and Mbt at the ZA is interdependent, indicating that their functions during ZA morphogenesis are interlinked. In this context, we find the Rap1-GEF Dizzy is enriched at the ZA and our results suggest that it promotes Rap1 activity during ZA morphogenesis. Altogether, we propose the Dizzy, Rap1 and Cno pathway and Mbt converge in regulating the interface between Bazooka and AJ material to promote ZA morphogenesis. PMID:29507112

MicroRNA miR-328 Regulates Zonation Morphogenesis by Targeting CD44 Expression

PubMed Central

Wang, Chia-Hui; Lee, Daniel Y.; Deng, Zhaoqun; Jeyapalan, Zina; Lee, Shao-Chen; Kahai, Shireen; Lu, Wei-Yang; Zhang, Yaou; Yang, Burton B.

2008-01-01

Morphogenesis is crucial to initiate physiological development and tumor invasion. Here we show that a microRNA controls zonation morphogenesis by targeting hyaluronan receptor CD44. We have developed a novel system to study microRNA functions by generating constructs expressing pre-miRNAs and mature miRNAs. Using this system, we have demonstrated that expression of miR-328 reduced cell adhesion, aggregation, and migration, and regulated formation of capillary structure. Protein analysis indicated that miR-328 repressed CD44 expression. Activities of luciferase constructs harboring the target site in CD44, but not the one containing mutation, were repressed by miR-328. Zonation morphogenesis appeared in cells transfected by miR-328: miR-328-transfected cells were present on the surface of zonating structures while the control cells stayed in the middle. MiR-328-mediated CD44 actions was validated by anti-CD44 antibody, hyaluronidase, CD44 siRNA, and CD44 expression constructs. In vivo experiments showed that CD44-silencing cells appeared as layers on the surfaces of nodules or zonating structures. Immuno-histochemistry also exhibited CD44-negative cells on the surface layers of normal rat livers and the internal zones of Portal veins. Our results demonstrate that miR-328 targets CD44, which is essential in regulating zonation morphogenesis: silencing of CD44 expression is essential in sealing the zonation structures to facilitate their extension and to inhibit complex expansion. PMID:18560585

MicroRNA miR-328 regulates zonation morphogenesis by targeting CD44 expression.

PubMed

Wang, Chia-Hui; Lee, Daniel Y; Deng, Zhaoqun; Jeyapalan, Zina; Lee, Shao-Chen; Kahai, Shireen; Lu, Wei-Yang; Zhang, Yaou; Yang, Burton B

2008-06-18

Morphogenesis is crucial to initiate physiological development and tumor invasion. Here we show that a microRNA controls zonation morphogenesis by targeting hyaluronan receptor CD44. We have developed a novel system to study microRNA functions by generating constructs expressing pre-miRNAs and mature miRNAs. Using this system, we have demonstrated that expression of miR-328 reduced cell adhesion, aggregation, and migration, and regulated formation of capillary structure. Protein analysis indicated that miR-328 repressed CD44 expression. Activities of luciferase constructs harboring the target site in CD44, but not the one containing mutation, were repressed by miR-328. Zonation morphogenesis appeared in cells transfected by miR-328: miR-328-transfected cells were present on the surface of zonating structures while the control cells stayed in the middle. MiR-328-mediated CD44 actions was validated by anti-CD44 antibody, hyaluronidase, CD44 siRNA, and CD44 expression constructs. In vivo experiments showed that CD44-silencing cells appeared as layers on the surfaces of nodules or zonating structures. Immuno-histochemistry also exhibited CD44-negative cells on the surface layers of normal rat livers and the internal zones of Portal veins. Our results demonstrate that miR-328 targets CD44, which is essential in regulating zonation morphogenesis: silencing of CD44 expression is essential in sealing the zonation structures to facilitate their extension and to inhibit complex expansion.

Role of the rttA gene in morphogenesis, stress response, and virulence in the human pathogenic fungus Penicillium marneffei.

PubMed

Suwunnakorn, Sumanun; Cooper, Chester R; Kummasook, Aksarakorn; Pongpom, Monsicha; Vanittanakom, Pramote; Vanittanakom, Nongnuch

2015-02-01

Penicillium marneffei is a human pathogenic fungus and the only thermally dimorphic species of the genus. At 25°C, P. marneffei grows as a mycelium that produces conidia in chains. However, when incubated at 37°C or following infection of host tissue, the fungus develops as a fission yeast. Previously, a mutant (strain I133) defective in morphogenesis was generated via Agrobacterium-mediated transformation. Specifically, the rtt109 gene (subsequently designated rttA) in this mutant was interrupted by T-DNA insertion. We characterized strain I133 and the possible roles of the mutated rttA gene in altered P. marneffei phenotypes. At 25°C, the rttA mutant produces fewer conidia than the wild type and a complemented mutant strain, as well as slower rates of conidial germination; however, strain I133 continued to grow as a yeast in 37°C-incubated cultures. Furthermore, whereas the wild type exhibited increased expression of rttA at 37°C in response to the DNA-damaging agent methyl methane sulfonate, strain I133 was hypersensitive to this and other genotoxic agents. Under similar conditions, the rttA mutant exhibited decreased expression of genes associated with carbohydrate metabolism and oxidative stress. Importantly, when compared with the wild-type and the complemented strain, I133 was significantly less virulent in a Galleria infection model when the larvae were incubated at 37°C. Moreover, the mutant exhibited inappropriate phase transition in vivo. In conclusion, the rttA gene plays important roles in morphogenesis, carbohydrate metabolism, stress response, and pathogenesis in P. marneffei, suggesting that this gene may be a potential target for the development of antifungal compounds. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Tuning Hsf1 levels drives distinct fungal morphogenetic programs with depletion impairing Hsp90 function and overexpression expanding the target space.

PubMed

Veri, Amanda O; Miao, Zhengqiang; Shapiro, Rebecca S; Tebbji, Faiza; O'Meara, Teresa R; Kim, Sang Hu; Colazo, Juan; Tan, Kaeling; Vyas, Valmik K; Whiteway, Malcolm; Robbins, Nicole; Wong, Koon Ho; Cowen, Leah E

2018-03-01

The capacity to respond to temperature fluctuations is critical for microorganisms to survive within mammalian hosts, and temperature modulates virulence traits of diverse pathogens. One key temperature-dependent virulence trait of the fungal pathogen Candida albicans is its ability to transition from yeast to filamentous growth, which is induced by environmental cues at host physiological temperature. A key regulator of temperature-dependent morphogenesis is the molecular chaperone Hsp90, which has complex functional relationships with the transcription factor Hsf1. Although Hsf1 controls global transcriptional remodeling in response to heat shock, its impact on morphogenesis remains unknown. Here, we establish an intriguing paradigm whereby overexpression or depletion of C. albicans HSF1 induces morphogenesis in the absence of external cues. HSF1 depletion compromises Hsp90 function, thereby driving filamentation. HSF1 overexpression does not impact Hsp90 function, but rather induces a dose-dependent expansion of Hsf1 direct targets that drives overexpression of positive regulators of filamentation, including Brg1 and Ume6, thereby bypassing the requirement for elevated temperature during morphogenesis. This work provides new insight into Hsf1-mediated environmentally contingent transcriptional control, implicates Hsf1 in regulation of a key virulence trait, and highlights fascinating biology whereby either overexpression or depletion of a single cellular regulator induces a profound developmental transition.

Tuning Hsf1 levels drives distinct fungal morphogenetic programs with depletion impairing Hsp90 function and overexpression expanding the target space

PubMed Central

Miao, Zhengqiang; Tan, Kaeling; Vyas, Valmik K.; Whiteway, Malcolm; Robbins, Nicole; Wong, Koon Ho; Cowen, Leah E.

2018-01-01

The capacity to respond to temperature fluctuations is critical for microorganisms to survive within mammalian hosts, and temperature modulates virulence traits of diverse pathogens. One key temperature-dependent virulence trait of the fungal pathogen Candida albicans is its ability to transition from yeast to filamentous growth, which is induced by environmental cues at host physiological temperature. A key regulator of temperature-dependent morphogenesis is the molecular chaperone Hsp90, which has complex functional relationships with the transcription factor Hsf1. Although Hsf1 controls global transcriptional remodeling in response to heat shock, its impact on morphogenesis remains unknown. Here, we establish an intriguing paradigm whereby overexpression or depletion of C. albicans HSF1 induces morphogenesis in the absence of external cues. HSF1 depletion compromises Hsp90 function, thereby driving filamentation. HSF1 overexpression does not impact Hsp90 function, but rather induces a dose-dependent expansion of Hsf1 direct targets that drives overexpression of positive regulators of filamentation, including Brg1 and Ume6, thereby bypassing the requirement for elevated temperature during morphogenesis. This work provides new insight into Hsf1-mediated environmentally contingent transcriptional control, implicates Hsf1 in regulation of a key virulence trait, and highlights fascinating biology whereby either overexpression or depletion of a single cellular regulator induces a profound developmental transition. PMID:29590106

Emergent material properties of developing epithelial tissues.

PubMed

Machado, Pedro F; Duque, Julia; Étienne, Jocelyn; Martinez-Arias, Alfonso; Blanchard, Guy B; Gorfinkiel, Nicole

2015-11-23

Force generation and the material properties of cells and tissues are central to morphogenesis but remain difficult to measure in vivo. Insight is often limited to the ratios of mechanical properties obtained through disruptive manipulation, and the appropriate models relating stress and strain are unknown. The Drosophila amnioserosa epithelium progressively contracts over 3 hours of dorsal closure, during which cell apices exhibit area fluctuations driven by medial myosin pulses with periods of 1.5-6 min. Linking these two timescales and understanding how pulsatile contractions drive morphogenetic movements is an urgent challenge. We present a novel framework to measure in a continuous manner the mechanical properties of epithelial cells in the natural context of a tissue undergoing morphogenesis. We show that the relationship between apicomedial myosin fluorescence intensity and strain during fluctuations is consistent with a linear behaviour, although with a lag. We thus used myosin fluorescence intensity as a proxy for active force generation and treated cells as natural experiments of mechanical response under cyclic loading, revealing unambiguous mechanical properties from the hysteresis loop relating stress to strain. Amnioserosa cells can be described as a contractile viscoelastic fluid. We show that their emergent mechanical behaviour can be described by a linear viscoelastic rheology at timescales relevant for tissue morphogenesis. For the first time, we establish relative changes in separate effective mechanical properties in vivo. Over the course of dorsal closure, the tissue solidifies and effective stiffness doubles as net contraction of the tissue commences. Combining our findings with those from previous laser ablation experiments, we show that both apicomedial and junctional stress also increase over time, with the relative increase in apicomedial stress approximately twice that of other obtained measures. Our results show that in an epithelial tissue undergoing net contraction, stiffness and stress are coupled. Dorsal closure cell apical contraction is driven by the medial region where the relative increase in stress is greater than that of stiffness. At junctions, by contrast, the relative increase in the mechanical properties is the same, so the junctional contribution to tissue deformation is constant over time. An increase in myosin activity is likely to underlie, at least in part, the change in medioapical properties and we suggest that its greater effect on stress relative to stiffness is fundamental to actomyosin systems and confers on tissues the ability to regulate contraction rates in response to changes in external mechanics.

Ras GTPases Modulate Morphogenesis, Sporulation and Cellulase Gene Expression in the Cellulolytic Fungus Trichoderma reesei

PubMed Central

Zhang, Jiwei; Zhang, Yanmei; Zhong, Yaohua; Qu, Yinbo; Wang, Tianhong

2012-01-01

Background The model cellulolytic fungus Trichoderma reesei (teleomorph Hypocrea jecorina) is capable of responding to environmental cues to compete for nutrients in its natural saprophytic habitat despite its genome encodes fewer degradative enzymes. Efficient signalling pathways in perception and interpretation of environmental signals are indispensable in this process. Ras GTPases represent a kind of critical signal proteins involved in signal transduction and regulation of gene expression. In T. reesei the genome contains two Ras subfamily small GTPases TrRas1 and TrRas2 homologous to Ras1 and Ras2 from S. cerevisiae, but their functions remain unknown. Methodology/Principal Findings Here, we have investigated the roles of GTPases TrRas1 and TrRas2 during fungal morphogenesis and cellulase gene expression. We show that both TrRas1 and TrRas2 play important roles in some cellular processes such as polarized apical growth, hyphal branch formation, sporulation and cAMP level adjustment, while TrRas1 is more dominant in these processes. Strikingly, we find that TrRas2 is involved in modulation of cellulase gene expression. Deletion of TrRas2 results in considerably decreased transcription of cellulolytic genes upon growth on cellulose. Although the strain carrying a constitutively activated TrRas2G16V allele exhibits increased cellulase gene transcription, the cbh1 and cbh2 expression in this mutant still strictly depends on cellulose, indicating TrRas2 does not directly mediate the transmission of the cellulose signal. In addition, our data suggest that the effect of TrRas2 on cellulase gene is exerted through regulation of transcript abundance of cellulase transcription factors such as Xyr1, but the influence is independent of cAMP signalling pathway. Conclusions/Significance Together, these findings elucidate the functions for Ras signalling of T. reesei in cellular morphogenesis, especially in cellulase gene expression, which contribute to deciphering the powerful competitive ability of plant cell wall degrading fungi in nature. PMID:23152805

Mutant laboratory mice with abnormalities in hair follicle morphogenesis, cycling, and/or structure: an update.

PubMed

Nakamura, Motonobu; Schneider, Marlon R; Schmidt-Ullrich, Ruth; Paus, Ralf

2013-01-01

Human hair disorders comprise a number of different types of alopecia, atrichia, hypotrichosis, distinct hair shaft disorders as well as hirsutism and hypertrichosis. Their causes vary from genodermatoses (e.g. hypotrichoses) via immunological disorders (e.g. alopecia areata, autoimmune cicatrical alopecias) to hormone-dependent abnormalities (e.g. androgenetic alopecia). A large number of spontaneous mouse mutants and genetically engineered mice develop abnormalities in hair follicle morphogenesis, cycling, and/or hair shaft formation, whose analysis has proven invaluable to define the molecular regulation of hair growth, ranging from hair follicle development, and cycling to hair shaft formation and stem cell biology. Also, the accumulating reports on hair phenotypes of mouse strains provide important pointers to better understand the molecular mechanisms underlying human hair growth disorders. Since numerous new mouse mutants with a hair phenotype have been reported since the publication of our earlier review on this matter a decade ago, we present here an updated, tabulated mini-review. The updated annotated tables list a wide selection of mouse mutants with hair growth abnormalities, classified into four categories: Mutations that affect hair follicle (1) morphogenesis, (2) cycling, (3) structure, and (4) mutations that induce extrafollicular events (for example immune system defects) resulting in secondary hair growth abnormalities. This synthesis is intended to provide a useful source of reference when studying the molecular controls of hair follicle growth and differentiation, and whenever the hair phenotypes of a newly generated mouse mutant need to be compared with existing ones. Copyright © 2012 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

Pak4 Is Required during Epithelial Polarity Remodeling through Regulating AJ Stability and Bazooka Retention at the ZA.

PubMed

Walther, Rhian F; Nunes de Almeida, Francisca; Vlassaks, Evi; Burden, Jemima J; Pichaud, Franck

2016-04-05

The ability of epithelial cells to assemble into sheets relies on their zonula adherens (ZA), a circumferential belt of adherens junction (AJ) material, which can be remodeled during development to shape organs. Here, we show that during ZA remodeling in a model neuroepithelial cell, the Cdc42 effector P21-activated kinase 4 (Pak4/Mbt) regulates AJ morphogenesis and stability through β-catenin (β-cat/Arm) phosphorylation. We find that β-catenin phosphorylation by Mbt, and associated AJ morphogenesis, is needed for the retention of the apical determinant Par3/Bazooka at the remodeling ZA. Importantly, this retention mechanism functions together with Par1-dependent lateral exclusion of Par3/Bazooka to regulate apical membrane differentiation. Our results reveal an important functional link between Pak4, AJ material morphogenesis, and polarity remodeling during organogenesis downstream of Par3. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Oligomerization-Dependent Regulation of Motility and Morphogenesis by the Collagen Xviii Nc1/Endostatin Domain

PubMed Central

Kuo, Calvin J.; LaMontagne, Kenneth R.; Garcia-Cardeña, Guillermo; Ackley, Brian D.; Kalman, Daniel; Park, Susan; Christofferson, Rolf; Kamihara, Junne; Ding, Yuan-Hua; Lo, Kin-Ming; Gillies, Stephen; Folkman, Judah; Mulligan, Richard C.; Javaherian, Kashi

2001-01-01

Collagen XVIII (c18) is a triple helical endothelial/epithelial basement membrane protein whose noncollagenous (NC)1 region trimerizes a COOH-terminal endostatin (ES) domain conserved in vertebrates, Caenorhabditis elegans and Drosophila. Here, the c18 NC1 domain functioned as a motility-inducing factor regulating the extracellular matrix (ECM)-dependent morphogenesis of endothelial and other cell types. This motogenic activity required ES domain oligomerization, was dependent on rac, cdc42, and mitogen-activated protein kinase, and exhibited functional distinction from the archetypal motogenic scatter factors hepatocyte growth factor and macrophage stimulatory protein. The motility-inducing and mitogen-activated protein kinase–stimulating activities of c18 NC1 were blocked by its physiologic cleavage product ES monomer, consistent with a proteolysis-dependent negative feedback mechanism. These data indicate that the collagen XVIII NC1 region encodes a motogen strictly requiring ES domain oligomerization and suggest a previously unsuspected mechanism for ECM regulation of motility and morphogenesis. PMID:11257123

Embryologic and Fetal Development of the Human Eyelid

PubMed Central

Abdulhafez, Mohamed H.; Fouad, Yousef A.; Dutton, Jonathan J.

2016-01-01

Purpose: To review the recent data about eyelid morphogenesis, and outline a timeline for eyelid development from the very early stages during embryonic life till final maturation of the eyelid late in fetal life. Methods: The authors extensively review major studies detailing human embryologic and fetal eyelid morphogenesis. These studies span almost a century and include some more recent cadaver studies. Numerous studies in the murine model have helped to better understand the molecular signals that govern eyelid embryogenesis. The authors summarize the current findings in molecular biology, and highlight the most significant studies in mice regarding the multiple and interacting signaling pathways involved in regulating normal eyelid morphogenesis. Results: Eyelid morphogenesis involves a succession of subtle yet strictly regulated morphogenetic episodes of tissue folding, proliferation, contraction, and even migration, which may occur simultaneously or in succession. Conclusions: Understanding the extraordinary process of building eyelid tissue in embryonic life, and deciphering its underlying signaling machinery has far reaching clinical implications beyond understanding the developmental abnormalities involving the eyelids, and may pave the way for achieving scar-reducing therapies in adult mammalian wounds, or control the spread of malignancies. PMID:27124372

Feedback, Lineages and Self-Organizing Morphogenesis

PubMed Central

Calof, Anne L.; Lowengrub, John S.; Lander, Arthur D.

2016-01-01

Feedback regulation of cell lineage progression plays an important role in tissue size homeostasis, but whether such feedback also plays an important role in tissue morphogenesis has yet to be explored. Here we use mathematical modeling to show that a particular feedback architecture in which both positive and negative diffusible signals act on stem and/or progenitor cells leads to the appearance of bistable or bi-modal growth behaviors, ultrasensitivity to external growth cues, local growth-driven budding, self-sustaining elongation, and the triggering of self-organization in the form of lamellar fingers. Such behaviors arise not through regulation of cell cycle speeds, but through the control of stem or progenitor self-renewal. Even though the spatial patterns that arise in this setting are the result of interactions between diffusible factors with antagonistic effects, morphogenesis is not the consequence of Turing-type instabilities. PMID:26989903

MT2-MMP-dependent release of collagen IV NC1 domains regulates submandibular gland branching morphogenesis.

PubMed

Rebustini, Ivan T; Myers, Christopher; Lassiter, Keyonica S; Surmak, Andrew; Szabova, Ludmila; Holmbeck, Kenn; Pedchenko, Vadim; Hudson, Billy G; Hoffman, Matthew P

2009-10-01

Proteolysis is essential during branching morphogenesis, but the roles of MT-MMPs and their proteolytic products are not clearly understood. Here, we discover that decreasing MT-MMP activity during submandibular gland branching morphogenesis decreases proliferation and increases collagen IV and MT-MMP expression. Specifically, reducing epithelial MT2-MMP profoundly decreases proliferation and morphogenesis, increases Col4a2 and intracellular accumulation of collagen IV, and decreases the proteolytic release of collagen IV NC1 domains. Importantly, we demonstrate the presence of collagen IV NC1 domains in developing tissue. Furthermore, recombinant collagen IV NC1 domains rescue branching morphogenesis after MT2-siRNA treatment, increasing MT-MMP and proproliferative gene expression via beta1 integrin and PI3K-AKT signaling. Additionally, HBEGF also rescues MT2-siRNA treatment, increasing NC1 domain release, proliferation, and MT2-MMP and Hbegf expression. Our studies provide mechanistic insight into how MT2-MMP-dependent release of bioactive NC1 domains from collagen IV is critical for integrating collagen IV synthesis and proteolysis with epithelial proliferation during branching morphogenesis.

Mechanism of the Synergistic Effect of Amiodarone and Fluconazole in Candida albicans▿ †

PubMed Central

Gamarra, Soledad; Rocha, Elousa Maria F.; Zhang, Yong-Qiang; Park, Steven; Rao, Rajini; Perlin, David S.

2010-01-01

The antiarrhythmic drug amiodarone has been found to have fungicidal activity. In Saccharomyces cerevisiae, its antifungal activity is mediated by calcium overload stress, which leads to a rapid nuclear accumulation of the calcineurin-regulated transcription factor CRZ1. In addition, low doses of amiodarone have been reported to be synergistic with fluconazole in fluconazole-resistant Candida albicans. To establish its mechanism of toxicity in C. albicans, we used expression profiling of key pathway genes to examine cellular responses to amiodarone alone and in combination with fluconazole. Gene expression profiling of 59 genes was done in five C. albicans strains (three fluconazole-susceptible strains and two fluconazole-resistant strains) after amiodarone and/or fluconazole exposure. Of the 59 genes, 27 analyzed showed a significant change (>2-fold) in expression levels after amiodarone exposure. The up- or downregulated genes included genes involved in Ca2+ homeostasis, cell wall synthesis, vacuolar/lysosomal transport, diverse pathway regulation, stress response, and pseudohyphal morphogenesis. As expected, fluconazole induces an increase in ergosterol pathway genes expression levels. The combination treatment significantly dampened the transcriptional response to either drug, suggesting that synergism was due to an inhibition of compensatory response pathways. This dampening resulted in a decrease in total ergosterol levels and decreased pseudohyphal formation, a finding consistent with decreased virulence in a murine candidiasis model. PMID:20194694

Yield and cold storage of Trichoderma conidia is influenced by substrate pH and storage temperature.

PubMed

Steyaert, Johanna M; Chomic, Anastasia; Nieto-Jacobo, Maria; Mendoza-Mendoza, Artemio; Hay, Amanda J; Braithwaite, Mark; Stewart, Alison

2017-05-01

In this study we examined the influence of the ambient pH during morphogenesis on conidial yield of Trichoderma sp. "atroviride B" LU132 and T. hamatum LU593 and storage at low temperatures. The ambient pH of the growth media had a dramatic influence on the level of Trichoderma conidiation and this was dependent on the strain and growth media. On malt-extract agar, LU593 yield decreased with increasing pH (3-6), whereas yield increased with increasing pH for LU132. During solid substrate production the reverse was true for LU132 whereby yield decreased with increasing pH. The germination potential of the conidia decreased significantly over time in cold storage and the rate of decline was a factor of the strain, pH during morphogenesis, growth media, and storage temperature. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wnt signalling controls the response to mechanical loading during zebrafish joint development

PubMed Central

Brunt, Lucy H.; Begg, Katie; Kague, Erika; Cross, Stephen

2017-01-01

Joint morphogenesis requires mechanical activity during development. Loss of mechanical strain causes abnormal joint development, which can impact long-term joint health. Although cell orientation and proliferation are known to shape the joint, dynamic imaging of developing joints in vivo has not been possible in other species. Using genetic labelling techniques in zebrafish we were able, for the first time, to dynamically track cell behaviours in intact moving joints. We identify that proliferation and migration, which contribute to joint morphogenesis, are mechanically controlled and are significantly reduced in immobilised larvae. By comparison with strain maps of the developing skeleton, we identify canonical Wnt signalling as a candidate for transducing mechanical forces into joint cell behaviours. We show that, in the jaw, Wnt signalling is reduced specifically in regions of high strain in response to loss of muscle activity. By pharmacological manipulation of canonical Wnt signalling, we demonstrate that Wnt acts downstream of mechanical activity and is required for joint patterning and chondrocyte maturation. Wnt16, which is also downstream of muscle activity, controls proliferation and migration, but plays no role in chondrocyte intercalation. PMID:28684625

Intersection of FOXO- and RUNX1-mediated gene expression programs in single breast epithelial cells during morphogenesis and tumor progression.

PubMed

Wang, Lixin; Brugge, Joan S; Janes, Kevin A

2011-10-04

Gene expression networks are complicated by the assortment of regulatory factors that bind DNA and modulate transcription combinatorially. Single-cell measurements can reveal biological mechanisms hidden by population averages, but their value has not been fully explored in the context of mRNA regulation. Here, we adapted a single-cell expression profiling technique to examine the gene expression program downstream of Forkhead box O (FOXO) transcription factors during 3D breast epithelial acinar morphogenesis. By analyzing patterns of mRNA fluctuations among individual matrix-attached epithelial cells, we found that a subset of FOXO target genes was jointly regulated by the transcription factor Runt-related transcription factor 1 (RUNX1). Knockdown of RUNX1 causes hyperproliferation and abnormal morphogenesis, both of which require normal FOXO function. Down-regulating RUNX1 and FOXOs simultaneously causes widespread oxidative stress, which arrests proliferation and restores normal acinar morphology. In hormone-negative breast cancers lacking human epidermal growth factor receptor 2 (HER2) amplification, we find that RUNX1 down-regulation is strongly associated with up-regulation of FOXO1, which may be required to support growth of RUNX1-negative tumors. The coordinate function of these two tumor suppressors may provide a failsafe mechanism that inhibits cancer progression.

Polycystin-1 Binds Par3/aPKC and Controls Convergent Extension During Renal Tubular Morphogenesis

PubMed Central

Castelli, Maddalena; Boca, Manila; Chiaravalli, Marco; Ramalingam, Harini; Rowe, Isaline; Distefano, Gianfranco; Carroll, Thomas; Boletta, Alessandra

2013-01-01

Several organs, including lungs and kidneys, are formed by epithelial tubes whose proper morphogenesis ensures correct function. This is best exemplified by the kidney, where defective establishment or maintanance of tubular diameter results in polycystic kidney disease, a common genetic disorder. Most polycystic kidney disease cases result from loss-of-function mutations in the PKD1 gene, encoding Polycystin-1 (PC-1), a large receptor of unknown function. Here we demonstrate that PC-1 plays an essential role in establishment of correct tubular diameter during nephron development. PC-1 associates with Par3 favoring the assembly of a pro-polarizing Par3/aPKC complex and it regulates a program of cell polarity important for oriented cell migration and for a convergent extension-like process during tubular morphogenesis. Par3 inactivation in the developing kidney results in defective convergent extension and tubular morphogenesis and in renal cyst formation. Our data define PC-1 as central to cell polarization and to epithelial tube morphogenesis and homeostasis. PMID:24153433

Polycystin-1 binds Par3/aPKC and controls convergent extension during renal tubular morphogenesis

NASA Astrophysics Data System (ADS)

Castelli, Maddalena; Boca, Manila; Chiaravalli, Marco; Ramalingam, Harini; Rowe, Isaline; Distefano, Gianfranco; Carroll, Thomas; Boletta, Alessandra

2013-10-01

Several organs, including the lungs and kidneys, are formed by epithelial tubes whose proper morphogenesis ensures correct function. This is best exemplified by the kidney, where defective establishment or maintenance of tubular diameter results in polycystic kidney disease, a common genetic disorder. Most polycystic kidney disease cases result from loss-of-function mutations in the PKD1 gene, encoding Polycystin-1, a large receptor of unknown function. Here we demonstrate that PC-1 has an essential role in the establishment of correct tubular diameter during nephron development. Polycystin-1 associates with Par3 favouring the assembly of a pro-polarizing Par3/aPKC complex and it regulates a programme of cell polarity important for oriented cell migration and for a convergent extension-like process during tubular morphogenesis. Par3 inactivation in the developing kidney results in defective convergent extension and tubular morphogenesis, and in renal cyst formation. Our data define Polycystin-1 as central to cell polarization and to epithelial tube morphogenesis and homeostasis.

CDKL5, a protein associated with rett syndrome, regulates neuronal morphogenesis via Rac1 signaling.

PubMed

Chen, Qian; Zhu, Yong-Chuan; Yu, Jing; Miao, Sheng; Zheng, Jing; Xu, Li; Zhou, Yang; Li, Dan; Zhang, Chi; Tao, Jiong; Xiong, Zhi-Qi

2010-09-22

Mutations in cyclin-dependent kinase-like 5 (CDKL5), also known as serine/threonine kinase 9 (STK9), have been identified in patients with Rett syndrome (RTT) and X-linked infantile spasm. However, the function of CDKL5 in the brain remains unknown. Here, we report that CDKL5 is a critical regulator of neuronal morphogenesis. We identified a neuron-specific splicing variant of CDKL5 whose expression was markedly induced during postnatal development of the rat brain. Downregulating CDKL5 by RNA interference (RNAi) in cultured cortical neurons inhibited neurite growth and dendritic arborization, whereas overexpressing CDKL5 had opposite effects. Furthermore, knocking down CDKL5 in the rat brain by in utero electroporation resulted in delayed neuronal migration, and severely impaired dendritic arborization. In contrast to its proposed function in the nucleus, we found that CDKL5 regulated dendrite development through a cytoplasmic mechanism. In fibroblasts and in neurons, CDKL5 colocalized and formed a protein complex with Rac1, a critical regulator of actin remodeling and neuronal morphogenesis. Overexpression of Rac1 prevented the inhibition of dendrite growth caused by CDKL5 knockdown, and the growth-promoting effect of ectopically expressed CDKL5 on dendrites was abolished by coexpressing a dominant-negative form of Rac1. Moreover, CDKL5 was required for brain-derived neurotrophic factor (BDNF)-induced activation of Rac1. Together, these results demonstrate a critical role of CDKL5 in neuronal morphogenesis and identify a Rho GTPase signaling pathway which may contribute to CDKL5-related disorders.

Multiple Phosphatidylinositol 3-Kinases Regulate Vaccinia Virus Morphogenesis

PubMed Central

McNulty, Shannon; Bornmann, William; Schriewer, Jill; Werner, Chas; Smith, Scott K.; Olson, Victoria A.; Damon, Inger K.; Buller, R. Mark; Heuser, John; Kalman, Daniel

2010-01-01

Poxvirus morphogenesis is a complex process that involves the successive wrapping of the virus in host cell membranes. We screened by plaque assay a focused library of kinase inhibitors for those that caused a reduction in viral growth and identified several compounds that selectively inhibit phosphatidylinositol 3-kinase (PI3K). Previous studies demonstrated that PI3Ks mediate poxviral entry. Using growth curves and electron microscopy in conjunction with inhibitors, we show that that PI3Ks additionally regulate morphogenesis at two distinct steps: immature to mature virion (IMV) transition, and IMV envelopment to form intracellular enveloped virions (IEV). Cells derived from animals lacking the p85 regulatory subunit of Type I PI3Ks (p85α−/−β−/−) presented phenotypes similar to those observed with PI3K inhibitors. In addition, VV appear to redundantly use PI3Ks, as PI3K inhibitors further reduce plaque size and number in p85α−/−β−/− cells. Together, these data provide evidence for a novel regulatory mechanism for virion morphogenesis involving phosphatidylinositol dynamics and may represent a new therapeutic target to contain poxviruses. PMID:20526370

The ciliopathy gene Rpgrip1l is essential for hair follicle development.

PubMed

Chen, Jiang; Laclef, Christine; Moncayo, Alejandra; Snedecor, Elizabeth R; Yang, Ning; Li, Li; Takemaru, Ken-Ichi; Paus, Ralf; Schneider-Maunoury, Sylvie; Clark, Richard A

2015-03-01

The primary cilium is essential for skin morphogenesis through regulating the Notch, Wnt, and hedgehog signaling pathways. Prior studies on the functions of primary cilia in the skin were based on the investigations of genes that are essential for cilium formation. However, none of these ciliogenic genes has been linked to ciliopathy, a group of disorders caused by abnormal formation or function of cilia. To determine whether there is a genetic and molecular link between ciliopathies and skin morphogenesis, we investigated the role of RPGRIP1L, a gene mutated in Joubert (JBTS) and Meckel (MKS) syndromes, two severe forms of ciliopathy, in the context of skin development. We found that RPGRIP1L is essential for hair follicle morphogenesis. Specifically, disrupting the Rpgrip1l gene in mice resulted in reduced proliferation and differentiation of follicular keratinocytes, leading to hair follicle developmental defects. These defects were associated with significantly decreased primary cilium formation and attenuated hedgehog signaling. In contrast, we found that hair follicle induction and polarization and the development of interfollicular epidermis were unaffected. This study indicates that RPGRIP1L, a ciliopathy gene, is essential for hair follicle morphogenesis likely through regulating primary cilia formation and the hedgehog signaling pathway.

TRPP2 ion channels: Critical regulators of organ morphogenesis in health and disease.

PubMed

Busch, Tilman; Köttgen, Michael; Hofherr, Alexis

2017-09-01

Ion channels control the membrane potential and mediate transport of ions across membranes. Archetypical physiological functions of ion channels include processes such as regulation of neuronal excitability, muscle contraction, or transepithelial ion transport. In that regard, transient receptor potential ion channel polycystin 2 (TRPP2) is remarkable, because it controls complex morphogenetic processes such as the establishment of properly shaped epithelial tubules and left-right-asymmetry of organs. The fascinating question of how an ion channel regulates morphogenesis has since captivated the attention of scientists in different disciplines. Four loosely connected key insights on different levels of biological complexity ranging from protein to whole organism have framed our understanding of TRPP2 physiology: 1) TRPP2 is a non-selective cation channel; 2) TRPP2 is part of a receptor-ion channel complex; 3) TRPP2 localizes to primary cilia; and 4) TRPP2 is required for organ morphogenesis. In this review, we will discuss the current knowledge in these key areas and highlight some of the challenges ahead. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

The mouse homeobox gene Noto regulates node morphogenesis, notochordal ciliogenesis, and left–right patterning

PubMed Central

Beckers, Anja; Alten, Leonie; Viebahn, Christoph; Andre, Philipp; Gossler, Achim

2007-01-01

The mouse homeobox gene Noto represents the homologue of zebrafish floating head (flh) and is expressed in the organizer node and in the nascent notochord. Previous analyses suggested that Noto is required exclusively for the formation of the caudal part of the notochord. Here, we show that Noto is also essential for node morphogenesis, controlling ciliogenesis in the posterior notochord, and the establishment of laterality, whereas organizer functions in anterior–posterior patterning are apparently not compromised. In mutant embryos, left–right asymmetry of internal organs and expression of laterality markers was randomized. Mutant posterior notochord regions were variable in size and shape, cilia were shortened with highly irregular axonemal microtubuli, and basal bodies were, in part, located abnormally deep in the cytoplasm. The transcription factor Foxj1, which regulates the dynein gene Dnahc11 and is required for the correct anchoring of basal bodies in lung epithelial cells, was down-regulated in mutant nodes. Likewise, the transcription factor Rfx3, which regulates cilia growth, was not expressed in Noto mutants, and various other genes important for cilia function or assembly such as Dnahc5 and Nphp3 were down-regulated. Our results establish Noto as an essential regulator of node morphogenesis and ciliogenesis in the posterior notochord, and suggest Noto acts upstream of Foxj1 and Rfx3. PMID:17884984

Adenosine kinase modulates root gravitropism and cap morphogenesis in Arabidopsis.

PubMed

Young, Li-Sen; Harrison, Benjamin R; Narayana Murthy, U M; Moffatt, Barbara A; Gilroy, Simon; Masson, Patrick H

2006-10-01

Adenosine kinase (ADK) is a key enzyme that regulates intra- and extracellular levels of adenosine, thereby modulating methyltransferase reactions, production of polyamines and secondary compounds, and cell signaling in animals. Unfortunately, little is known about ADK's contribution to the regulation of plant growth and development. Here, we show that ADK is a modulator of root cap morphogenesis and gravitropism. Upon gravistimulation, soluble ADK levels and activity increase in the root tip. Mutation in one of two Arabidopsis (Arabidopsis thaliana) ADK genes, ADK1, results in cap morphogenesis defects, along with alterations in root sensitivity to gravistimulation and slower kinetics of root gravitropic curvature. The kinetics defect can be partially rescued by adding spermine to the growth medium, whereas the defects in cap morphogenesis and gravitropic sensitivity cannot. The root morphogenesis and gravitropism defects of adk1-1 are accompanied by altered expression of the PIN3 auxin efflux facilitator in the cap and decreased expression of the auxin-responsive DR5-GUS reporter. Furthermore, PIN3 fails to relocalize to the bottom membrane of statocytes upon gravistimulation. Consequently, adk1-1 roots cannot develop a lateral auxin gradient across the cap, necessary for the curvature response. Interestingly, adk1-1 does not affect gravity-induced cytoplasmic alkalinization of the root statocytes, suggesting either that ADK1 functions between cytoplasmic alkalinization and PIN3 relocalization in a linear pathway or that the pH and PIN3-relocalization responses to gravistimulation belong to distinct branches of the pathway. Our data are consistent with a role for ADK and the S-adenosyl-L-methionine pathway in the control of root gravitropism and cap morphogenesis.

Adenosine Kinase Modulates Root Gravitropism and Cap Morphogenesis in Arabidopsis1[W][OA

PubMed Central

Young, Li-Sen; Harrison, Benjamin R.; U.M., Narayana Murthy; Moffatt, Barbara A.; Gilroy, Simon; Masson, Patrick H.

2006-01-01

Adenosine kinase (ADK) is a key enzyme that regulates intra- and extracellular levels of adenosine, thereby modulating methyltransferase reactions, production of polyamines and secondary compounds, and cell signaling in animals. Unfortunately, little is known about ADK's contribution to the regulation of plant growth and development. Here, we show that ADK is a modulator of root cap morphogenesis and gravitropism. Upon gravistimulation, soluble ADK levels and activity increase in the root tip. Mutation in one of two Arabidopsis (Arabidopsis thaliana) ADK genes, ADK1, results in cap morphogenesis defects, along with alterations in root sensitivity to gravistimulation and slower kinetics of root gravitropic curvature. The kinetics defect can be partially rescued by adding spermine to the growth medium, whereas the defects in cap morphogenesis and gravitropic sensitivity cannot. The root morphogenesis and gravitropism defects of adk1-1 are accompanied by altered expression of the PIN3 auxin efflux facilitator in the cap and decreased expression of the auxin-responsive DR5-GUS reporter. Furthermore, PIN3 fails to relocalize to the bottom membrane of statocytes upon gravistimulation. Consequently, adk1-1 roots cannot develop a lateral auxin gradient across the cap, necessary for the curvature response. Interestingly, adk1-1 does not affect gravity-induced cytoplasmic alkalinization of the root statocytes, suggesting either that ADK1 functions between cytoplasmic alkalinization and PIN3 relocalization in a linear pathway or that the pH and PIN3-relocalization responses to gravistimulation belong to distinct branches of the pathway. Our data are consistent with a role for ADK and the S-adenosyl-l-methionine pathway in the control of root gravitropism and cap morphogenesis. PMID:16891550

Regulation of polarized morphogenesis by protein kinase C iota in oncogenic epithelial spheroids.

PubMed

Linch, Mark; Sanz-Garcia, Marta; Rosse, Carine; Riou, Philippe; Peel, Nick; Madsen, Chris D; Sahai, Erik; Downward, Julian; Khwaja, Asim; Dillon, Christian; Roffey, Jon; Cameron, Angus J M; Parker, Peter J

2014-02-01

Protein kinase C iota (PKCι), a serine/threonine kinase required for cell polarity, proliferation and migration, is commonly up- or downregulated in cancer. PKCι is a human oncogene but whether this is related to its role in cell polarity and what repertoire of oncogenes acts in concert with PKCι is not known. We developed a panel of candidate oncogene expressing Madin-Darby canine kidney (MDCK) cells and demonstrated that H-Ras, ErbB2 and phosphatidylinositol 3-kinase transformation led to non-polar spheroid morphogenesis (dysplasia), whereas MDCK spheroids expressing c-Raf or v-Src were largely polarized. We show that small interfering RNA (siRNA)-targeting PKCι decreased the size of all spheroids tested and partially reversed the aberrant polarity phenotype in H-Ras and ErbB2 spheroids only. This indicates distinct requirements for PKCι and moreover that different thresholds of PKCι activity are required for these phenotypes. By manipulating PKCι function using mutant constructs, siRNA depletion or chemical inhibition, we have demonstrated that PKCι is required for polarization of parental MDCK epithelial cysts in a 3D matrix and that there is a threshold of PKCι activity above and below which, disorganized epithelial morphogenesis results. Furthermore, treatment with a novel PKCι inhibitor, CRT0066854, was able to restore polarized morphogenesis in the dysplastic H-Ras spheroids. These results show that tightly regulated PKCι is required for normal-polarized morphogenesis in mammalian cells and that H-Ras and ErbB2 cooperate with PKCι for loss of polarization and dysplasia. The identification of a PKCι inhibitor that can restore polarized morphogenesis has implications for the treatment of Ras and ErbB2 driven malignancies.

MT2-MMP-dependent release of collagen IV NC1 domains regulates submandibular gland branching morphogenesis

PubMed Central

Rebustini, Ivan T.; Myers, Christopher; Lassiter, Keyonica S.; Surmak, Andrew; Szabova, Ludmila; Holmbeck, Kenn; Pedchenko, Vadim; Hudson, Billy G.; Hoffman, Matthew P.

2009-01-01

Summary Proteolysis is essential during branching morphogenesis, but the roles of MT-MMPs and their proteolytic products are not clearly understood. Here we discover that decreasing MT-MMP activity during submandibular gland branching morphogenesis decreases proliferation and increases collagen IV and MT-MMP expression. Importantly, reducing epithelial MT2-MMP profoundly decreases proliferation and morphogenesis, increases Col4a2 and intracellular accumulation of collagen IV, and decreases the proteolytic release of collagen IV NC1 domains. Importantly, we demonstrate the presence of collagen IV NC1 domains in developing tissue. Furthermore, recombinant collagen IV NC1 domains rescue branching morphogenesis after MT2-siRNA-treatment, increasing MT-MMP and pro-proliferative gene expression via β1 integrin and PI3K-AKT signaling. Additionally, HBEGF also rescues MT2-siRNA-treatment, increasing NC1 domain release, proliferation, and MT2-MMP and Hbegf expression. Our studies provide mechanistic insight into how MT2-MMP-dependent release of bioactive NC1 domains from collagen IV is critical for integrating collagen IV synthesis and proteolysis with epithelial proliferation during branching morphogenesis. PMID:19853562

Rac1/RhoA antagonism defines cell-to-cell heterogeneity during epidermal morphogenesis in nematodes

PubMed Central

Ouellette, Marie-Hélène

2016-01-01

The antagonism between the GTPases Rac1 and RhoA controls cell-to-cell heterogeneity in isogenic populations of cells in vitro and epithelial morphogenesis in vivo. Its involvement in the regulation of cell-to-cell heterogeneity during epidermal morphogenesis has, however, never been addressed. We used a quantitative cell imaging approach to characterize epidermal morphogenesis at a single-cell level during early elongation of Caenorhabditis elegans embryos. This study reveals that a Rac1-like pathway, involving the Rac/Cdc42 guanine-exchange factor β-PIX/PIX-1 and effector PAK1/PAK-1, and a RhoA-like pathway, involving ROCK/LET-502, control the remodeling of apical junctions and the formation of basolateral protrusions in distinct subsets of hypodermal cells. In these contexts, protrusions adopt lamellipodia or an amoeboid morphology. We propose that lamella formation may reduce tension building at cell–cell junctions during morphogenesis. Cell-autonomous antagonism between these pathways enables cells to switch between Rac1- and RhoA-like morphogenetic programs. This study identifies the first case of cell-to-cell heterogeneity controlled by Rac1/RhoA antagonism during epidermal morphogenesis. PMID:27821782

Cellular growth in plants requires regulation of cell wall biochemistry.

PubMed

Chebli, Youssef; Geitmann, Anja

2017-02-01

Cell and organ morphogenesis in plants are regulated by the chemical structure and mechanical properties of the extracellular matrix, the cell wall. The two primary load bearing components in the plant cell wall, the pectin matrix and the cellulose/xyloglucan network, are constantly remodelled to generate the morphological changes required during plant development. This remodelling is regulated by a plethora of loosening and stiffening agents such as pectin methyl-esterases, calcium ions, expansins, and glucanases. The tight spatio-temporal regulation of the activities of these agents is a sine qua non condition for proper morphogenesis at cell and tissue levels. The pectin matrix and the cellulose-xyloglucan network operate in concert and their behaviour is mutually dependent on their chemical, structural and mechanical modifications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Morphological regulation of Aspergillus niger to improve citric acid production by chsC gene silencing.

PubMed

Sun, Xiaowen; Wu, Hefang; Zhao, Genhai; Li, Zhemin; Wu, Xihua; Liu, Hui; Zheng, Zhiming

2018-04-02

The mycelial morphology of Aspergillus niger, a major filamentous fungus used for citric acid production, is important for citric acid synthesis during submerged fermentation. To investigate the involvement of the chitin synthase gene, chsC, in morphogenesis and citric acid production in A. niger, an RNAi system was constructed to silence chsC and the morphological mutants were screened after transformation. The compactness of the mycelial pellets was obviously reduced in the morphological mutants, with lower proportion of dispersed mycelia. These morphological changes have caused a decrease in viscosity and subsequent improvement in oxygen and mass transfer efficiency, which may be conducive for citric acid accumulation. All the transformants exhibited improvements in citric acid production; in particular, chsC-3 showed 42.6% higher production than the original strain in the shake flask. Moreover, the high-yield strain chsC-3 exhibited excellent citric acid production potential in the scale-up process.The citric acid yield and the conversion rate of glucose of chsC-3 were both improved by 3.6%, when compared with that of the original strain in the stirred tank bioreactor.

Characterization of the Candida albicans Amino Acid Permease Family: Gap2 Is the Only General Amino Acid Permease and Gap4 Is an S-Adenosylmethionine (SAM) Transporter Required for SAM-Induced Morphogenesis.

PubMed

Kraidlova, Lucie; Schrevens, Sanne; Tournu, Hélène; Van Zeebroeck, Griet; Sychrova, Hana; Van Dijck, Patrick

2016-01-01

Amino acids are key sources of nitrogen for growth of Candida albicans . In order to detect and take up these amino acids from a broad range of different and changing nitrogen sources inside the host, this fungus must be able to adapt via its expression of genes for amino acid uptake and further metabolism. We analyzed six C. albicans putative general amino acid permeases based on their homology to the Saccharomyces cerevisiae Gap1 general amino acid permease. We generated single- and multiple-deletion strains and found that, based on growth assays and transcriptional or posttranscriptional regulation, Gap2 is the functional orthologue to Sc Gap1, with broad substrate specificity. Expression analysis showed that expression of all GAP genes is under control of the Csy1 amino acid sensor, which is different from the situation in S. cerevisiae , where the expression of ScGAP1 is not regulated by Ssy1. We show that Gap4 is the functional orthologue of Sc Sam3, the only S -adenosylmethionine (SAM) transporter in S. cerevisiae , and we report that Gap4 is required for SAM-induced morphogenesis. IMPORTANCE Candida albicans is a commensal organism that can thrive in many niches in its human host. The environmental conditions at these different niches differ quite a bit, and this fungus must be able to sense these changes and adapt its metabolism to them. Apart from glucose and other sugars, the uptake of amino acids is very important. This is underscored by the fact that the C. albicans genome encodes 6 orthologues of the Saccharomyces. cerevisiae general amino acid permease Gap1 and many other amino acid transporters. In this work, we characterize these six permeases and we show that C. albicans Gap2 is the functional orthologue of Sc Gap1 and that C. albicans Gap4 is an orthologue of Sc Sam3, an S -adenosylmethionine (SAM) transporter. Furthermore, we show that Gap4 is required for SAM-induced morphogenesis, an important virulence factor of C. albicans .

Connexin 43 Is Necessary for Salivary Gland Branching Morphogenesis and FGF10-induced ERK1/2 Phosphorylation*

PubMed Central

Yamada, Aya; Futagi, Masaharu; Fukumoto, Emiko; Saito, Kan; Yoshizaki, Keigo; Ishikawa, Masaki; Arakaki, Makiko; Hino, Ryoko; Sugawara, Yu; Ishikawa, Momoko; Naruse, Masahiro; Miyazaki, Kanako; Nakamura, Takashi; Fukumoto, Satoshi

2016-01-01

Cell-cell interaction via the gap junction regulates cell growth and differentiation, leading to formation of organs of appropriate size and quality. To determine the role of connexin43 in salivary gland development, we analyzed its expression in developing submandibular glands (SMGs). Connexin43 (Cx43) was found to be expressed in salivary gland epithelium. In ex vivo organ cultures of SMGs, addition of the gap junctional inhibitors 18α-glycyrrhetinic acid (18α-GA) and oleamide inhibited SMG branching morphogenesis, suggesting that gap junctional communication contributes to salivary gland development. In Cx43−/− salivary glands, submandibular and sublingual gland size was reduced as compared with those from heterozygotes. The expression of Pdgfa, Pdgfb, Fgf7, and Fgf10, which induced branching of SMGs in Cx43−/− samples, were not changed as compared with those from heterozygotes. Furthermore, the blocking peptide for the hemichannel and gap junction channel showed inhibition of terminal bud branching. FGF10 induced branching morphogenesis, while it did not rescue the Cx43−/− phenotype, thus Cx43 may regulate FGF10 signaling during salivary gland development. FGF10 is expressed in salivary gland mesenchyme and regulates epithelial proliferation, and was shown to induce ERK1/2 phosphorylation in salivary epithelial cells, while ERK1/2 phosphorylation in HSY cells was dramatically inhibited by 18α-GA, a Cx43 peptide or siRNA. On the other hand, PDGF-AA and PDGF-BB separately induced ERK1/2 phosphorylation in primary cultured salivary mesenchymal cells regardless of the presence of 18α-GA. Together, our results suggest that Cx43 regulates FGF10-induced ERK1/2 phosphorylation in salivary epithelium but not in mesenchyme during the process of SMG branching morphogenesis. PMID:26565022

Muscle contraction controls skeletal morphogenesis through regulation of chondrocyte convergent extension.

PubMed

Shwartz, Yulia; Farkas, Zsuzsanna; Stern, Tomer; Aszódi, Attila; Zelzer, Elazar

2012-10-01

Convergent extension driven by mediolateral intercalation of chondrocytes is a key process that contributes to skeletal growth and morphogenesis. While progress has been made in deciphering the molecular mechanism that underlies this process, the involvement of mechanical load exerted by muscle contraction in its regulation has not been studied. Using the zebrafish as a model system, we found abnormal pharyngeal cartilage morphology in both chemically and genetically paralyzed embryos, demonstrating the importance of muscle contraction for zebrafish skeletal development. The shortening of skeletal elements was accompanied by prominent changes in cell morphology and organization. While in control the cells were elongated, chondrocytes in paralyzed zebrafish were smaller and exhibited a more rounded shape, confirmed by a reduction in their length-to-width ratio. The typical columnar organization of cells was affected too, as chondrocytes in various skeletal elements exhibited abnormal stacking patterns, indicating aberrant intercalation. Finally, we demonstrate impaired chondrocyte intercalation in growth plates of muscle-less Sp(d) mouse embryos, implying the evolutionary conservation of muscle force regulation of this essential morphogenetic process.Our findings provide a new perspective on the regulatory interaction between muscle contraction and skeletal morphogenesis by uncovering the role of muscle-induced mechanical loads in regulating chondrocyte intercalation in two different vertebrate models. Copyright © 2012 Elsevier Inc. All rights reserved.

Retinoic Acid signaling regulates Krt5 and Krt14 independently of stem cell markers in submandibular salivary gland epithelium

PubMed Central

Abashev, Timur M.; Metzler, Melissa A.; Wright, Diana M.; Sandell, Lisa L.

2017-01-01

Background Retinoic Acid (RA), the active metabolite of Vitamin A, has been demonstrated to be important for growth and branching morphogenesis of mammalian embryonic salivary gland epithelium. However, it is not known whether RA functions directly within epithelial cells or in associated tissues that influence morphogenesis of salivary epithelium. Moreover, downstream targets of RA regulation have not been identified. Results Here we show that canonical RA signaling occurs in multiple tissues of embryonic mouse salivary glands, including epithelium, associated parasympathetic ganglion neurons, and non-neuronal mesenchyme. By culturing epithelium explants in isolation from other tissues we demonstrate that RA influences epithelium morphogenesis by direct action in that tissue. Moreover, we demonstrate that inhibition of RA signaling represses cell proliferation and expression of FGF10 signaling targets, and upregulates expression of basal epithelial keratins Krt5 and Krt14. Importantly, we show that the stem cell gene Kit is regulated inversely from Krt5/Krt14 by RA signaling. Conclusions RA regulates Krt5 and Krt14 expression independently of stem cell character in developing salivary epithelium. RA, or chemical inhibitors of RA signaling, could potentially be used for modulating growth and differentiation of epithelial stem cells for the purpose of re-populating damaged glands or generating bioengineered organs. PMID:27884045

Autocrine and paracrine Shh signaling are necessary for tooth morphogenesis, but not tooth replacement in snakes and lizards (Squamata).

PubMed

Handrigan, Gregory R; Richman, Joy M

2010-01-01

Here we study the role of Shh signaling in tooth morphogenesis and successional tooth initiation in snakes and lizards (Squamata). By characterizing the expression of Shh pathway receptor Ptc1 in the developing dentitions of three species (Eublepharis macularius, Python regius, and Pogona vitticeps) and by performing gain- and loss-of-function experiments, we demonstrate that Shh signaling is active in the squamate tooth bud and is required for its normal morphogenesis. Shh apparently mediates tooth morphogenesis by separate paracrine- and autocrine-mediated functions. According to this model, paracrine Shh signaling induces cell proliferation in the cervical loop, outer enamel epithelium, and dental papilla. Autocrine signaling within the stellate reticulum instead appears to regulate cell survival. By treating squamate dental explants with Hh antagonist cyclopamine, we induced tooth phenotypes that closely resemble the morphological and differentiation defects of vestigial, first-generation teeth in the bearded dragon P. vitticeps. Our finding that these vestigial teeth are deficient in epithelial Shh signaling further corroborates that Shh is needed for the normal development of teeth in snakes and lizards. Finally, in this study, we definitively refute a role for Shh signaling in successional dental lamina formation and conclude that other pathways regulate tooth replacement in squamates.

Lamellipodia-based migrations of larval epithelial cells are required for normal closure of the adult epidermis of Drosophila

PubMed Central

Bischoff, Marcus

2012-01-01

Cell migrations are an important feature of animal development. They are, furthermore, essential to wound healing and tumour progression. Despite recent progress, it is still mysterious how cell migration is spatially and temporally regulated during morphogenesis and how cell migration is coordinated with other cellular behaviours to shape tissues and organs. The formation of the abdominal epithelium of Drosophila during metamorphosis provides an attractive system to study morphogenesis. Here, the diploid adult histoblasts replace the polyploid larval epithelial cells (LECs). Using in vivo 4D microscopy, I show that, besides apical constriction and apoptosis, the LECs undergo extensive coordinated migrations. The migrations follow a transition from a stationary (epithelial) to a migratory mode. The migratory behaviour is stimulated by autocrine Dpp signalling. Directed apical lamellipodia-like protrusions propel the cells. Initially, planar cell polarity determines the orientation of LEC migration. While LECs are migrating they also constrict apically, and changes in activity of the small GTPase Rho1 can favour one behaviour over the other. This study shows that the LECs play a more active role in morphogenesis than previously thought, with their migrations contributing to abdominal closure. It furthermore provides insights into how the migratory behaviour of cells is regulated during morphogenesis. PMID:22230614

Neurofibromin interacts with CRMP-2 and CRMP-4 in rat brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Y.-L.; Hsueh, Y.-P., E-mail: yph@gate.sinica.edu.tw

Neurofibromin, encoded by the neurofibromatosis type 1 (NF1) gene, regulates the Ras and cAMP pathways and plays a role in proliferation and neuronal morphogenesis. The details of the molecular mechanism of neurofibromin action in these processes are still unclear. In this study, immunoprecipitation and proteomics were used to identify novel proteins from rat brain that interact with neurofibromin. Mass spectrometry analysis showed that two proteins, the collapsin response mediator protein-2 (CRMP-2) and propionyl-CoA carboxylase alpha chain (PCCA), associated with neurofibromin. Immunoprecipitation-immunoblotting analysis confirmed the interactions between neurofibromin and CRMP-2 and CRMP-4, but not CRMP-1, in rat brain. CDK5, a kinasemore » that regulates CRMP-2 in axonal outgrowth, was required for the interaction between neurofibromin and CRMP-2. Since both neurofibromin and CRMP proteins are involved in proliferation and axonal morphogenesis, these results suggest that the interaction with CRMPs contributes to the function of neurofibromin in tumorigenesis and neuronal morphogenesis.« less

Endothelial Snail Regulates Capillary Branching Morphogenesis via Vascular Endothelial Growth Factor Receptor 3 Expression

PubMed Central

Park, Jeong Ae; Kim, Dong Young; Kim, Young-Myeong; Kwon, Young-Guen

2015-01-01

Vascular branching morphogenesis is activated and maintained by several signaling pathways. Among them, vascular endothelial growth factor receptor 2 (VEGFR2) signaling is largely presented in arteries, and VEGFR3 signaling is in veins and capillaries. Recent reports have documented that Snail, a well-known epithelial-to-mesenchymal transition protein, is expressed in endothelial cells, where it regulates sprouting angiogenesis and embryonic vascular development. Here, we identified Snail as a regulator of VEGFR3 expression during capillary branching morphogenesis. Snail was dramatically upregulated in sprouting vessels in the developing retinal vasculature, including the leading-edged vessels and vertical sprouting vessels for capillary extension toward the deep retina. Results from in vitro functional studies demonstrate that Snail expression colocalized with VEGFR3 and upregulated VEGFR3 mRNA by directly binding to the VEGFR3 promoter via cooperating with early growth response protein-1. Snail knockdown in postnatal mice attenuated the formation of the deep capillary plexus, not only by impairing vertical sprouting vessels but also by downregulating VEGFR3 expression. Collectively, these data suggest that the Snail-VEGFR3 axis controls capillary extension, especially in vessels expressing VEGFR2 at low levels. PMID:26147525

Dbl3 drives Cdc42 signaling at the apical margin to regulate junction position and apical differentiation

PubMed Central

Zihni, Ceniz; Munro, Peter M.G.; Elbediwy, Ahmed; Keep, Nicholas H.; Terry, Stephen J.; Harris, John

2014-01-01

Epithelial cells develop morphologically characteristic apical domains that are bordered by tight junctions, the apical–lateral border. Cdc42 and its effector complex Par6–atypical protein kinase c (aPKC) regulate multiple steps during epithelial differentiation, but the mechanisms that mediate process-specific activation of Cdc42 to drive apical morphogenesis and activate the transition from junction formation to apical differentiation are poorly understood. Using a small interfering RNA screen, we identify Dbl3 as a guanine nucleotide exchange factor that is recruited by ezrin to the apical membrane, that is enriched at a marginal zone apical to tight junctions, and that drives spatially restricted Cdc42 activation, promoting apical differentiation. Dbl3 depletion did not affect junction formation but did affect epithelial morphogenesis and brush border formation. Conversely, expression of active Dbl3 drove process-specific activation of the Par6–aPKC pathway, stimulating the transition from junction formation to apical differentiation and domain expansion, as well as the positioning of tight junctions. Thus, Dbl3 drives Cdc42 signaling at the apical margin to regulate morphogenesis, apical–lateral border positioning, and apical differentiation. PMID:24379416

Mechanics and morphogenesis of fission yeast cells.

PubMed

Davì, Valeria; Minc, Nicolas

2015-12-01

The integration of biochemical and biomechanical elements is at the heart of morphogenesis. While animal cells are relatively soft objects which shape and mechanics is mostly regulated by cytoskeletal networks, walled cells including those of plants, fungi and bacteria are encased in a rigid cell wall which resist high internal turgor pressure. How these particular mechanical properties may influence basic cellular processes, such as growth, shape and division remains poorly understood. Recent work using the model fungal cell fission yeast, Schizosaccharomyces pombe, highlights important contribution of cell mechanics to various morphogenesis processes. We envision this genetically tractable system to serve as a novel standard for the mechanobiology of walled cell. Copyright © 2015 Elsevier Ltd. All rights reserved.

Tissue-specific activities of the Fat1 cadherin cooperate to control neuromuscular morphogenesis

PubMed Central

2018-01-01

Muscle morphogenesis is tightly coupled with that of motor neurons (MNs). Both MNs and muscle progenitors simultaneously explore the surrounding tissues while exchanging reciprocal signals to tune their behaviors. We previously identified the Fat1 cadherin as a regulator of muscle morphogenesis and showed that it is required in the myogenic lineage to control the polarity of progenitor migration. To expand our knowledge on how Fat1 exerts its tissue-morphogenesis regulator activity, we dissected its functions by tissue-specific genetic ablation. An emblematic example of muscle under such morphogenetic control is the cutaneous maximus (CM) muscle, a flat subcutaneous muscle in which progenitor migration is physically separated from the process of myogenic differentiation but tightly associated with elongating axons of its partner MNs. Here, we show that constitutive Fat1 disruption interferes with expansion and differentiation of the CM muscle, with its motor innervation and with specification of its associated MN pool. Fat1 is expressed in muscle progenitors, in associated mesenchymal cells, and in MN subsets, including the CM-innervating pool. We identify mesenchyme-derived connective tissue (CT) as a cell type in which Fat1 activity is required for the non–cell-autonomous control of CM muscle progenitor spreading, myogenic differentiation, motor innervation, and for motor pool specification. In parallel, Fat1 is required in MNs to promote their axonal growth and specification, indirectly influencing muscle progenitor progression. These results illustrate how Fat1 coordinates the coupling of muscular and neuronal morphogenesis by playing distinct but complementary actions in several cell types. PMID:29768404

Repressor of Estrogen Receptor Activity (REA) Is Essential for Mammary Gland Morphogenesis and Functional Activities: Studies in Conditional Knockout Mice

PubMed Central

Park, Sunghee; Zhao, Yuechao; Yoon, Sangyeon; Xu, Jianming; Liao, Lan; Lydon, John; DeMayo, Franco; O'Malley, Bert W.

2011-01-01

Estrogen receptor (ER) is a key regulator of mammary gland development and is also implicated in breast tumorigenesis. Because ER-mediated activities depend critically on coregulator partner proteins, we have investigated the consequences of reduction or loss of function of the coregulator repressor of ER activity (REA) by conditionally deleting one allele or both alleles of the REA gene at different stages of mammary gland development. Notably, we find that heterozygosity and nullizygosity for REA result in very different mammary phenotypes and that REA has essential roles in the distinct morphogenesis and functions of the mammary gland at different stages of development, pregnancy, and lactation. During puberty, mice homozygous null for REA in the mammary gland (REAf/f PRcre/+) showed severely impaired mammary ductal elongation and morphogenesis, whereas mice heterozygous for REA (REAf/+ PRcre/+) displayed accelerated mammary ductal elongation, increased numbers of terminal end buds, and up-regulation of amphiregulin, the major paracrine mediator of estrogen-induced ductal morphogenesis. During pregnancy and lactation, mice with homozygous REA gene deletion in mammary epithelium (REAf/f whey acidic protein-Cre) showed a loss of lobuloalveolar structures and increased apoptosis of mammary alveolar epithelium, leading to impaired milk production and significant reduction in growth of their offspring, whereas body weights of the offspring nursed by females heterozygous for REA were slightly greater than those of control mice. Our findings reveal that REA is essential for mammary gland development and has a gene dosage-dependent role in the regulation of stage-specific physiological functions of the mammary gland. PMID:21862609

Sequoia, a tramtrack-related zinc finger protein, functions as a pan-neural regulator for dendrite and axon morphogenesis in Drosophila.

PubMed

Brenman, J E; Gao, F B; Jan, L Y; Jan, Y N

2001-11-01

Morphological complexity of neurons contributes to their functional complexity. How neurons generate different dendritic patterns is not known. We identified the sequoia mutant from a previous screen for dendrite mutants. Here we report that Sequoia is a pan-neural nuclear protein containing two putative zinc fingers homologous to the DNA binding domain of Tramtrack. sequoia mutants affect the cell fate decision of a small subset of neurons but have global effects on axon and dendrite morphologies of most and possibly all neurons. In support of sequoia as a specific regulator of neuronal morphogenesis, microarray experiments indicate that sequoia may regulate downstream genes that are important for executing neurite development rather than altering a variety of molecules that specify cell fates.

The solid state environment orchestrates embryonic development and tissue remodeling

NASA Technical Reports Server (NTRS)

Damsky, C. H.; Moursi, A.; Zhou, Y.; Fisher, S. J.; Globus, R. K.

1997-01-01

Cell interactions with extracellular matrix and with other cells play critical roles in morphogenesis during development and in tissue homeostasis and remodeling throughout life. Extracellular matrix is information-rich, not only because it is comprised of multifunctional structural ligands for cell surface adhesion receptors, but also because it contains peptide signaling factors, and proteinases and their inhibitors. The functions of these groups of molecules are extensively interrelated. In this review, three primary cell culture models are described that focus on adhesion receptors and their roles in complex aspects of morphogenesis and remodeling: the regulation of proteinase expression by fibronectin and integrins in synovial fibroblasts; the regulation of osteoblast differentiation and survival by fibronectin, and the regulation of trophoblast differentiation and invasion by integrins, cadherins and immunoglobulin family adhesion receptors.

The MARVEL domain protein Nce102 regulates actin organization and invasive growth of Candida albicans.

PubMed

Douglas, Lois M; Wang, Hong X; Konopka, James B

2013-11-26

Invasive growth of the fungal pathogen Candida albicans into tissues promotes disseminated infections in humans. The plasma membrane is essential for pathogenesis because this important barrier mediates morphogenesis and invasive growth, as well as secretion of virulence factors, cell wall synthesis, nutrient import, and other processes. Previous studies showed that the Sur7 tetraspan protein that localizes to MCC (membrane compartment occupied by Can1)/eisosome subdomains of the plasma membrane regulates a broad range of key functions, including cell wall synthesis, morphogenesis, and resistance to copper. Therefore, a distinct tetraspan protein found in MCC/eisosomes, Nce102, was investigated. Nce102 belongs to the MARVEL domain protein family, which is implicated in regulating membrane structure and function. Deletion of NCE102 did not cause the broad defects seen in sur7Δ cells. Instead, the nce102Δ mutant displayed a unique phenotype in that it was defective in forming hyphae and invading low concentrations of agar but could invade well in higher agar concentrations. This phenotype was likely due to a defect in actin organization that was observed by phalloidin staining. In support of this, the invasive growth defect of a bni1Δ mutant that mislocalizes actin due to lack of the Bni1 formin was also reversed at high agar concentrations. This suggests that a denser matrix provides a signal that compensates for the actin defects. The nce102Δ mutant displayed decreased virulence and formed abnormal hyphae in mice. These studies identify novel ways that Nce102 and the physical environment surrounding C. albicans regulate morphogenesis and pathogenesis. The plasma membrane promotes virulence of the human fungal pathogen Candida albicans by acting as a protective barrier around the cell and mediating dynamic activities, such as morphogenesis, cell wall synthesis, secretion of virulence factors, and nutrient uptake. To better understand how the plasma membrane contributes to virulence, we analyzed a set of eight genes encoding MARVEL family proteins that are predicted to function in membrane organization. Interestingly, deletion of one gene, NCE102, caused a strong defect in formation of invasive hyphal growth in vitro and decreased virulence in mice. The nce102Δ mutant cells showed defects in actin organization that underlie the morphogenesis defect, since mutation of a known regulator of actin organization caused a similar defect. These studies identify a novel way in which the plasma membrane regulates the actin cytoskeleton and contributes to pathogenesis.

Expression and Functional Role of Sprouty-2 in Breast Morphogenesis

PubMed Central

Hilmarsdottir, Bylgja; Gustafsdottir, Sigrun M.; Franzdottir, Sigridur Rut; Arason, Ari Jon; Steingrimsson, Eirikur; Magnusson, Magnus K.; Gudjonsson, Thorarinn

2013-01-01

Branching morphogenesis is a mechanism used by many species for organogenesis and tissue maintenance. Receptor tyrosine kinases (RTKs), including epidermal growth factor receptor (EGFR) and the sprouty protein family are believed to be critical regulators of branching morphogenesis. The aim of this study was to analyze the expression of Sprouty-2 (SPRY2) in the mammary gland and study its role in branching morphogenesis. Human breast epithelial cells, breast tissue and mouse mammary glands were used for expression studies using immunoblotting, real rime PCR and immunohistochemistry. Knockdown of SPRY2 in the breast epithelial stem cell line D492 was done by lentiviral transduction of shRNA constructs targeting SPRY2. Three dimensional culture of D492 with or without endothelial cells was done in reconstituted basement membrane matrix. We show that in the human breast, SPRY2 is predominantly expressed in the luminal epithelial cells of both ducts and lobuli. In the mouse mammary gland, SPRY2 expression is low or absent in the virgin state, while in the pregnant mammary gland SPRY2 is expressed at branching epithelial buds with increased expression during lactation. This expression pattern is closely associated with the activation of the EGFR pathway. Using D492 which generates branching structures in three-dimensional (3D) culture, we show that SPRY2 expression is low during initiation of branching with subsequent increase throughout the branching process. Immunostaining locates expression of phosphorylated SPRY2 and EGFR at the tip of lobular-like, branching ends. SPRY2 knockdown (KD) resulted in increased migration, increased pERK and larger and more complex branching structures indicating a loss of negative feedback control during branching morphogenesis. In D492 co-cultures with endothelial cells, D492 SPRY2 KD generates spindle-like colonies that bear hallmarks of epithelial to mesenchymal transition. These data indicate that SPRY2 is an important regulator of branching morphogenesis and epithelial to mesenchymal transition in the mammary gland. PMID:23573284

Expression and functional role of sprouty-2 in breast morphogenesis.

PubMed

Sigurdsson, Valgardur; Ingthorsson, Saevar; Hilmarsdottir, Bylgja; Gustafsdottir, Sigrun M; Franzdottir, Sigridur Rut; Arason, Ari Jon; Steingrimsson, Eirikur; Magnusson, Magnus K; Gudjonsson, Thorarinn

2013-01-01

Branching morphogenesis is a mechanism used by many species for organogenesis and tissue maintenance. Receptor tyrosine kinases (RTKs), including epidermal growth factor receptor (EGFR) and the sprouty protein family are believed to be critical regulators of branching morphogenesis. The aim of this study was to analyze the expression of Sprouty-2 (SPRY2) in the mammary gland and study its role in branching morphogenesis. Human breast epithelial cells, breast tissue and mouse mammary glands were used for expression studies using immunoblotting, real rime PCR and immunohistochemistry. Knockdown of SPRY2 in the breast epithelial stem cell line D492 was done by lentiviral transduction of shRNA constructs targeting SPRY2. Three dimensional culture of D492 with or without endothelial cells was done in reconstituted basement membrane matrix. We show that in the human breast, SPRY2 is predominantly expressed in the luminal epithelial cells of both ducts and lobuli. In the mouse mammary gland, SPRY2 expression is low or absent in the virgin state, while in the pregnant mammary gland SPRY2 is expressed at branching epithelial buds with increased expression during lactation. This expression pattern is closely associated with the activation of the EGFR pathway. Using D492 which generates branching structures in three-dimensional (3D) culture, we show that SPRY2 expression is low during initiation of branching with subsequent increase throughout the branching process. Immunostaining locates expression of phosphorylated SPRY2 and EGFR at the tip of lobular-like, branching ends. SPRY2 knockdown (KD) resulted in increased migration, increased pERK and larger and more complex branching structures indicating a loss of negative feedback control during branching morphogenesis. In D492 co-cultures with endothelial cells, D492 SPRY2 KD generates spindle-like colonies that bear hallmarks of epithelial to mesenchymal transition. These data indicate that SPRY2 is an important regulator of branching morphogenesis and epithelial to mesenchymal transition in the mammary gland.

Development and Function of the Drosophila Tracheal System.

PubMed

Hayashi, Shigeo; Kondo, Takefumi

2018-06-01

The tracheal system of insects is a network of epithelial tubules that functions as a respiratory organ to supply oxygen to various target organs. Target-derived signaling inputs regulate stereotyped modes of cell specification, branching morphogenesis, and collective cell migration in the embryonic stage. In the postembryonic stages, the same set of signaling pathways controls highly plastic regulation of size increase and pattern elaboration during larval stages, and cell proliferation and reprograming during metamorphosis. Tracheal tube morphogenesis is also regulated by physicochemical interaction of the cell and apical extracellular matrix to regulate optimal geometry suitable for air flow. The trachea system senses both the external oxygen level and the metabolic activity of internal organs, and helps organismal adaptation to changes in environmental oxygen level. Cellular and molecular mechanisms underlying the high plasticity of tracheal development and physiology uncovered through research on Drosophila are discussed. Copyright © 2018 by the Genetics Society of America.

Clg2p interacts with Clf and ClUrase to regulate appressorium formation, pathogenicity and conidial morphology in Curvularia lunata.

PubMed

Liu, Tong; Wang, Yuying; Ma, Bingchen; Hou, Jumei; Jin, Yazhong; Zhang, Youli; Ke, Xiwang; Tai, Lianmei; Zuo, Yuhu; Dey, Kishore

2016-04-04

Ras is a small GTPase that regulates numerous processes in the cellular development and morphogenesis of many organisms. In this study, we identified and functionally characterized the Clg2p gene of Curvularia lunata, which is homologous with the Ras protein. The Clg2p deletion mutant (ΔClg2p) had altered appressorium formation and conidial morphology and produced fewer, smaller lesions compared with the wild-type strain. When a dominant Clg2p allele was introduced into the mutant, all of these defective phenotypes were completely restored. To further understand the regulation of Clg2p in appressorium formation and conidial morphology, and its role in pathogenicity, seven Clg2p-interacting proteins were screened using a yeast two-hybrid assay. Two of these proteins, Clf, a homologue of Mst11, which corresponds to MAP kinase kinase kinase in Magnaporthe oryzae, and urate oxidase (designated ClUrase) were functionally characterized. Clg2p specifically interacted with Clf through its RA domain to regulate appressorium formation and pathogenicity, whereas the Clg2p-ClUrase interaction regulated conidial morphology without affecting fungal pathogenicity. This report is the first to elucidate the regulatory mechanism of the key Ras protein Clg2p in C. lunata.

Retinoic acid signaling regulates Krt5 and Krt14 independently of stem cell markers in submandibular salivary gland epithelium.

PubMed

Abashev, Timur M; Metzler, Melissa A; Wright, Diana M; Sandell, Lisa L

2017-02-01

Retinoic acid (RA), the active metabolite of vitamin A, has been demonstrated to be important for growth and branching morphogenesis of mammalian embryonic salivary gland epithelium. However, it is not known whether RA functions directly within epithelial cells or in associated tissues that influence morphogenesis of salivary epithelium. Moreover, downstream targets of RA regulation have not been identified. Here, we show that canonical RA signaling occurs in multiple tissues of embryonic mouse salivary glands, including epithelium, associated parasympathetic ganglion neurons, and nonneuronal mesenchyme. By culturing epithelium explants in isolation from other tissues, we demonstrate that RA influences epithelium morphogenesis by direct action in that tissue. Moreover, we demonstrate that inhibition of RA signaling represses cell proliferation and expression of FGF10 signaling targets, and upregulates expression of basal epithelial keratins Krt5 and Krt14. Importantly, we show that the stem cell gene Kit is regulated inversely from Krt5/Krt14 by RA signaling. RA regulates Krt5 and Krt14 expression independently of stem cell character in developing salivary epithelium. RA, or chemical inhibitors of RA signaling, could potentially be used for modulating growth and differentiation of epithelial stem cells for the purpose of re-populating damaged glands or generating bioengineered organs. Developmental Dynamics 246:135-147, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Eph/Ephrin signalling maintains eye field segregation from adjacent neural plate territories during forebrain morphogenesis

PubMed Central

Cavodeassi, Florencia; Ivanovitch, Kenzo; Wilson, Stephen W.

2013-01-01

During forebrain morphogenesis, there is extensive reorganisation of the cells destined to form the eyes, telencephalon and diencephalon. Little is known about the molecular mechanisms that regulate region-specific behaviours and that maintain the coherence of cell populations undergoing specific morphogenetic processes. In this study, we show that the activity of the Eph/Ephrin signalling pathway maintains segregation between the prospective eyes and adjacent regions of the anterior neural plate during the early stages of forebrain morphogenesis in zebrafish. Several Ephrins and Ephs are expressed in complementary domains in the prospective forebrain and combinatorial abrogation of their activity results in incomplete segregation of the eyes and telencephalon and in defective evagination of the optic vesicles. Conversely, expression of exogenous Ephs or Ephrins in regions of the prospective forebrain where they are not usually expressed changes the adhesion properties of the cells, resulting in segregation to the wrong domain without changing their regional fate. The failure of eye morphogenesis in rx3 mutants is accompanied by a loss of complementary expression of Ephs and Ephrins, suggesting that this pathway is activated downstream of the regional fate specification machinery to establish boundaries between domains undergoing different programmes of morphogenesis. PMID:24026122

Polarized protein transport and lumen formation during epithelial tissue morphogenesis.

PubMed

Blasky, Alex J; Mangan, Anthony; Prekeris, Rytis

2015-01-01

One of the major challenges in biology is to explain how complex tissues and organs arise from the collective action of individual polarized cells. The best-studied model of this process is the cross talk between individual epithelial cells during their polarization to form the multicellular epithelial lumen during tissue morphogenesis. Multiple mechanisms of apical lumen formation have been proposed. Some epithelial lumens form from preexisting polarized epithelial structures. However, de novo lumen formation from nonpolarized cells has recently emerged as an important driver of epithelial tissue morphogenesis, especially during the formation of small epithelial tubule networks. In this review, we discuss the latest findings regarding the mechanisms and regulation of de novo lumen formation in vitro and in vivo.

Morphogenesis and gravity in a whole amphibian embryo and in isolated blastomeres of sea urchins.

PubMed

Izumi-Kurotani, Akemi; Kiyomoto, Masato

2003-01-01

Fertilization and subsequent embryogenesis of newts occurred normally under microgravity in two Astronewt flight experiments. By accumulation of the results from the amphibian flight experiments including 'Astronewt', it is considered that gravity has rather small effects on the early development of amphibian eggs. However, some temporary abnormalities, which recover in the course of the further developmental process, have been observed. Some regulations may occur in whole embryos. For a thorough knowledge about the role of gravity in morphogenesis, we need to investigate the gravitational effects on a single cell in a whole embryo. We propose a new experimental system with sea urchin embryos and micromeres for further studies at a cellular level of the effects of gravity on morphogenesis.

Genetic Interaction of Centrosomin and Bazooka in Apical Domain Regulation in Drosophila Photoreceptor

PubMed Central

Chen, Geng; Rogers, Alicia K.; League, Garrett P.; Nam, Sang-Chul

2011-01-01

Background Cell polarity genes including Crumbs (Crb) and Par complexes are essential for controlling photoreceptor morphogenesis. Among the Crb and Par complexes, Bazooka (Baz, Par-3 homolog) acts as a nodal component for other cell polarity proteins. Therefore, finding other genes interacting with Baz will help us to understand the cell polarity genes' role in photoreceptor morphogenesis. Methodology/Principal Findings Here, we have found a genetic interaction between baz and centrosomin (cnn). Cnn is a core protein for centrosome which is a major microtubule-organizing center. We analyzed the effect of the cnn mutation on developing eyes to determine its role in photoreceptor morphogenesis. We found that Cnn is dispensable for retinal differentiation in eye imaginal discs during the larval stage. However, photoreceptors deficient in Cnn display dramatic morphogenesis defects including the mislocalization of Crumbs (Crb) and Bazooka (Baz) during mid-stage pupal eye development, suggesting that Cnn is specifically required for photoreceptor morphogenesis during pupal eye development. This role of Cnn in apical domain modulation was further supported by Cnn's gain-of-function phenotype. Cnn overexpression in photoreceptors caused the expansion of the apical Crb membrane domain, Baz and adherens junctions (AJs). Conclusions/Significance These results strongly suggest that the interaction of Baz and Cnn is essential for apical domain and AJ modulation during photoreceptor morphogenesis, but not for the initial photoreceptor differentiation in the Drosophila photoreceptor. PMID:21253601

Looking into the sea urchin embryo you can see local cell interactions regulate morphogenesis.

PubMed

Wilt, F H

1997-08-01

The transparent sea urchin embryo provides a laboratory for study of morphogenesis. The calcareous endoskeleton is formed by a syncytium of mesenchyme cells in the blastocoel. The locations of mesenchyme in the blastocoel, the size of the skeleton, and even the branching pattern of the skeletal rods, are governed by interactions with the blastula wall. Now Guss and Ettensohn show that the rate of deposition of CaCO3 in the skeleton is locally controlled in the mesenchymal syncytium, as is the pattern of expression of three genes involved in skeleton formation. They propose that short range signals emanating from the blastula wall regulate many aspects of the biomineralization process.

Quantification of shape and cell polarity reveals a novel mechanism underlying malformations resulting from related FGF mutations during facial morphogenesis

PubMed Central

Li, Xin; Young, Nathan M.; Tropp, Stephen; Hu, Diane; Xu, Yanhua; Hallgrímsson, Benedikt; Marcucio, Ralph S.

2013-01-01

Fibroblast growth factor (FGF) signaling mutations are a frequent contributor to craniofacial malformations including midfacial anomalies and craniosynostosis. FGF signaling has been shown to control cellular mechanisms that contribute to facial morphogenesis and growth such as proliferation, survival, migration and differentiation. We hypothesized that FGF signaling not only controls the magnitude of growth during facial morphogenesis but also regulates the direction of growth via cell polarity. To test this idea, we infected migrating neural crest cells of chicken embryos with  replication-competent avian sarcoma virus expressing either FgfR2C278F, a receptor mutation found in Crouzon syndrome or the ligand Fgf8. Treated embryos exhibited craniofacial malformations resembling facial dysmorphologies in craniosynostosis syndrome. Consistent with our hypothesis, ectopic activation of FGF signaling resulted in decreased cell proliferation, increased expression of the Sprouty class of FGF signaling inhibitors, and repressed phosphorylation of ERK/MAPK. Furthermore, quantification of cell polarity in facial mesenchymal cells showed that while orientation of the Golgi body matches the direction of facial prominence outgrowth in normal cells, in FGF-treated embryos this direction is randomized, consistent with aberrant growth that we observed. Together, these data demonstrate that FGF signaling regulates cell proliferation and cell polarity and that these cell processes contribute to facial morphogenesis. PMID:23906837

A Global Analysis of Kinase Function in Candida albicans Hyphal Morphogenesis Reveals a Role for the Endocytosis Regulator Akl1

PubMed Central

Bar-Yosef, Hagit; Gildor, Tsvia; Ramírez-Zavala, Bernardo; Schmauch, Christian; Weissman, Ziva; Pinsky, Mariel; Naddaf, Rawi; Morschhäuser, Joachim; Arkowitz, Robert A.; Kornitzer, Daniel

2018-01-01

The human pathogenic fungus Candida albicans can switch between yeast and hyphal morphologies as a function of environmental conditions and cellular physiology. The yeast-to-hyphae morphogenetic switch is activated by well-established, kinase-based signal transduction pathways that are induced by extracellular stimuli. In order to identify possible inhibitory pathways of the yeast-to-hyphae transition, we interrogated a collection of C. albicans protein kinases and phosphatases ectopically expressed under the regulation of the TETon promoter. Proportionately more phosphatases than kinases were identified that inhibited hyphal morphogenesis, consistent with the known role of protein phosphorylation in hyphal induction. Among the kinases, we identified AKL1 as a gene that significantly suppressed hyphal morphogenesis in serum. Akl1 specifically affected hyphal elongation rather than initiation: overexpression of AKL1 repressed hyphal growth, and deletion of AKL1 resulted in acceleration of the rate of hyphal elongation. Akl1 suppressed fluid-phase endocytosis, probably via Pan1, a putative clathrin-mediated endocytosis scaffolding protein. In the absence of Akl1, the Pan1 patches were delocalized from the sub-apical region, and fluid-phase endocytosis was intensified. These results underscore the requirement of an active endocytic pathway for hyphal morphogenesis. Furthermore, these results suggest that under standard conditions, endocytosis is rate-limiting for hyphal elongation. PMID:29473018

A Global Analysis of Kinase Function in Candida albicans Hyphal Morphogenesis Reveals a Role for the Endocytosis Regulator Akl1.

PubMed

Bar-Yosef, Hagit; Gildor, Tsvia; Ramírez-Zavala, Bernardo; Schmauch, Christian; Weissman, Ziva; Pinsky, Mariel; Naddaf, Rawi; Morschhäuser, Joachim; Arkowitz, Robert A; Kornitzer, Daniel

2018-01-01

The human pathogenic fungus Candida albicans can switch between yeast and hyphal morphologies as a function of environmental conditions and cellular physiology. The yeast-to-hyphae morphogenetic switch is activated by well-established, kinase-based signal transduction pathways that are induced by extracellular stimuli. In order to identify possible inhibitory pathways of the yeast-to-hyphae transition, we interrogated a collection of C. albicans protein kinases and phosphatases ectopically expressed under the regulation of the TETon promoter. Proportionately more phosphatases than kinases were identified that inhibited hyphal morphogenesis, consistent with the known role of protein phosphorylation in hyphal induction. Among the kinases, we identified AKL1 as a gene that significantly suppressed hyphal morphogenesis in serum. Akl1 specifically affected hyphal elongation rather than initiation: overexpression of AKL1 repressed hyphal growth, and deletion of AKL1 resulted in acceleration of the rate of hyphal elongation. Akl1 suppressed fluid-phase endocytosis, probably via Pan1, a putative clathrin-mediated endocytosis scaffolding protein. In the absence of Akl1, the Pan1 patches were delocalized from the sub-apical region, and fluid-phase endocytosis was intensified. These results underscore the requirement of an active endocytic pathway for hyphal morphogenesis. Furthermore, these results suggest that under standard conditions, endocytosis is rate-limiting for hyphal elongation.

Altered tooth morphogenesis after silencing the planar cell polarity core component, Vangl2.

PubMed

Wu, Zhaoming; Epasinghe, Don Jeevanie; He, Jinquan; Li, Liwen; Green, David W; Lee, Min-Jung; Jung, Han-Sung

2016-12-01

Vangl2, one of the core components of the planar cell polarity (PCP) pathway, has an important role in the regulation of morphogenesis in several tissues. Although the expression of Vangl2 has been detected in the developing tooth, its role in tooth morphogenesis is not known. In this study, we show that Vangl2 is expressed in the inner dental epithelium (IDE) and in the secondary enamel knots (SEKs) of bell stage tooth germs. Inhibition of Vangl2 expression by siRNA treatment in in vitro-cultured tooth germs resulted in retarded tooth germ growth with deregulated cell proliferation and apoptosis. After kidney transplantation of Vangl2 siRNA-treated tooth germs, teeth were observed to be small and malformed. We also show that Vangl2 is required to maintain the proper pattern of cell alignment in SEKs, which maybe important for the function of SEKs as signaling centers. These results suggest that Vangl2 plays an important role in the morphogenesis of teeth.

Ngn3+ endocrine progenitor cells control the fate and morphogenesis of pancreatic ductal epithelium

PubMed Central

Magenheim, Judith; Klein, Allon M.; Stanger, Ben Z.; Ashery-Padan, Ruth; Sosa-Pineda, Beatriz; Gu, Guoqiang; Dor, Yuval

2013-01-01

Summary During pancreas development, endocrine and exocrine cells arise from a common multipotent progenitor pool. How these cell fate decisions are coordinated with tissue morphogenesis is poorly understood. Here we have examined ductal morphology, endocrine progenitor cell fate and Notch signaling in Ngn3−/− mice, which do not produce islet cells. Ngn3 deficiency results in reduced branching and enlarged pancreatic duct-like structures, concomitant with Ngn3 promoter activation throughout the ductal epithelium and reduced Notch signaling. Conversely, forced generation of surplus endocrine progenitor cells causes reduced duct caliber and an excessive number of tip cells. Thus, endocrine progenitor cells normally provide a feedback signal to adjacent multipotent ductal progenitor cells that activates Notch signaling, inhibits further endocrine differentiation and promotes proper morphogenesis. These results uncover a novel layer of regulation coordinating pancreas morphogenesis and endocrine/exocrine differentiation, and suggest ways to enhance the yield of beta-cells from stem cells. PMID:21888903

Zic1 and Zic4 regulate zebrafish roof plate specification and hindbrain ventricle morphogenesis

PubMed Central

Elsen, Gina E.; Choi, Louis; Millen, Kathleen; Grinblat, Yevgenya; Prince, Victoria E.

2008-01-01

During development, the lumen of the neural tube develops into a system of brain cavities or ventricles, which play important roles in normal CNS function. We have established that the formation of the hindbrain (4th) ventricle in zebrafish is dependent upon the pleiotropic functions of the genes implicated in human Dandy Walker Malformation, Zic1 and Zic4. Using morpholino knockdown we show that zebrafish Zic1 and Zic4 are required for normal morphogenesis of the 4th ventricle. In Zic1 and/or Zic4 morphants the ventricle does not open properly, but remains completely or partially fused from the level of rhombomere (r) 2 towards the posterior. In the absence of Zic function early hindbrain regionalization and neural crest development remain unaffected, but dorsal hindbrain progenitor cell proliferation is significantly reduced. Importantly, we find that Zic1 and Zic4 are required for development of the dorsal roof plate. In Zic morphants expression of roof plate markers, including lmx1b.1 and lmx1b.2, is disrupted. We further demonstrate that zebrafish Lmx1b function is required for both hindbrain roof plate development and 4th ventricle morphogenesis, confirming that roof plate formation is a critical component of ventricle development. Finally, we show that dorsal rhombomere boundary signaling centers depend on Zic1 and Zic4 function and on roof plate signals, and provide evidence that these boundary signals are also required for ventricle morphogenesis. In summary, we conclude that Zic1 and Zic4 control zebrafish 4th ventricle morphogenesis by regulating multiple mechanisms including cell proliferation and fate specification in the dorsal hindbrain. PMID:18191121

The role of Aspergillus flavus veA in the production of extracellular proteins during growth on starch substrates.

PubMed

Duran, Rocio M; Gregersen, Scott; Smith, Timothy D; Bhetariya, Preetida J; Cary, Jeffrey W; Harris-Coward, Pamela Y; Mattison, Christopher P; Grimm, Casey; Calvo, Ana M

2014-06-01

The aflatoxin-producer and opportunistic plant pathogenic, filamentous fungus Aspergillus flavus is responsible for the contamination of corn and other important agricultural commodities. In order to obtain nutrients from the host A. flavus produces a variety of extracellular hydrolytic enzymes. Interestingly, A. flavus amylase and protease activity are dependent on the global regulator veA, a gene known to regulate morphogenesis and secondary metabolism in numerous fungi. Analysis of starch degradation by fungal enzymes secreted into broths of starch- or corn kernel-based media showed a notable accumulation of glucose in samples of the A. flavus control strain while the deletion veA sample accumulated high levels of maltose and maltotriose and only a small amount of glucose. Furthermore, SDS-PAGE and proteomics analysis of culture broths from starch- or corn kernel-based media demonstrated differential production of a number of proteins that included a reduction in the amount of a glucoamylase protein in the veA mutant compared to the control strain, while an alpha-amylase was produced in greater quantities in the veA mutant. Quantitative real-time PCR and western blot analyses using anti-glucoamylase or alpha-amylase antisera supported the proteomics results. Additionally, an overall reduction in protease activity was observed in the veA mutant including production of the alkaline protease, oryzin, compared to the control strain. These findings contribute to our knowledge of mechanisms controlling production of hydrolases and other extracellular proteins during growth of A. flavus on natural starch-based substrates.

Phosphorylation of Rga2, a Cdc42 GAP, by CDK/Hgc1 is crucial for Candida albicans hyphal growth

PubMed Central

Zheng, Xin-De; Lee, Raymond Teck Ho; Wang, Yan-Ming; Lin, Qi-Shan; Wang, Yue

2007-01-01

Cyclin-dependent kinases (CDKs) control yeast morphogenesis, although how they regulate the polarity machinery remains unclear. The dimorphic fungus Candida albicans uses Cdc28/Hgc1, a CDK/cyclin complex, to promote persistent actin polarization for hyphal growth. Here, we report that Rga2, a GTPase-activating protein (GAP) of the central polarity regulator Cdc42, undergoes Hgc1-dependent hyperphosphorylation. Using the analog-sensitive Cdc28as mutant, we confirmed that Cdc28 controls Rga2 phosphorylation in vitro and in vivo. Deleting RGA2 produced elongated yeast cells without apparent effect on hyphal morphogenesis. However, deleting it or inactivating its GAP activity restored hyphal growth in hgc1Δ mutants, suggesting that Rga2 represses hyphal development and Cdc28/Hgc1 inactivates it upon hyphal induction. We provide evidence that Cdc28/Hgc1 may act to prevent Rga2 from localizing to hyphal tips, leading to localized Cdc42 activation for hyphal extension. Rga2 also undergoes transient Cdc28-dependent hyperphosphorylation at bud emergence, suggesting that regulating a GAP(s) of Cdc42 by CDKs may play an important role in governing different forms of polarized morphogenesis in yeast. This study reveals a direct molecular link between CDKs and the polarity machinery. PMID:17673907

The Role of Heparan Sulfate Proteoglycans in Optic Disc and Stalk Morphogenesis

PubMed Central

Cai, Zhigang; Grobe, Kay; Zhang, Xin

2014-01-01

Background Heparan sulfate proteoglycans (HSPG) are important for embryonic development via the regulation of gradient formation and signaling of multiple growth factors and morphogens. Previous studies have shown that Bmp/Shh/Fgf signaling are required for the regionalization of the optic vesicle (OV) and for the closure of the optic fissure (OF), the disturbance of which underlie ocular anomalies such as microphthalmia, coloboma and optic nerve hypoplasia. Results To study HSPG-dependent coordination of these signaling pathways during mammalian visual system development, we have generated a series of OV-specific mutations in the heparan sulfate (HS) N-sulfotransferase genes (Ndst1 and Ndst2) and HS O-sulfotransferase genes (Hs2st, Hs6st1 and Hs6st2) in mice. Interestingly, the resulting HS undersulfation still allowed for normal retinal neurogenesis and optic fissure closure, but led to defective optic disc and stalk development. The adult mutant animals further developed optic nerve aplasia/hypoplasia and displayed retinal degeneration. We observed that MAPK/ERK signaling was down-regulated in Ndst mutants, and consistent with this, HS-related optic nerve morphogenesis defects in mutant mice could partially be rescued by constitutive Kras activation. Conclusions These results suggest that HSPGs, depending on their HS sulfation pattern, regulate multiple signaling pathways in optic disc and stalk morphogenesis. PMID:24753163

Activation of YUCCA5 by the Transcription Factor TCP4 Integrates Developmental and Environmental Signals to Promote Hypocotyl Elongation in Arabidopsis.

PubMed

Challa, Krishna Reddy; Aggarwal, Pooja; Nath, Utpal

2016-09-05

Cell expansion is an essential process in plant morphogenesis and is regulated by the coordinated action of environmental stimuli and endogenous factors, such as the phytohormones auxin and brassinosteroid. Although the biosynthetic pathways that generate these hormones and their downstream signaling mechanisms have been extensively studied, the upstream transcriptional network that modulates their levels and connects their action to cell morphogenesis is less clear. Here we show that the miR319-regulated TCP (TEOSINTE BRANCHED 1, CYCLODEA, PROLIFERATING CELL FACTORS) transcription factors, notably TCP4, directly activate YUCCA5 transcription and integrate the auxin response to a brassinosteroid-dependent molecular circuit that promotes cell elongation in Arabidopsis hypocotyls. Further, TCP4 modulates the common transcriptional network downstream to auxin-BR signaling, which is also triggered by environmental cues, such as light, to promote cell expansion. Our study links TCP function with the hormone response during cell morphogenesis and shows that developmental and environmental signals converge on a common transcriptional network to promote cell elongation. {copyright, serif} 2016 American Society of Plant Biologists. All rights reserved.

Connexin 43 Is Necessary for Salivary Gland Branching Morphogenesis and FGF10-induced ERK1/2 Phosphorylation.

PubMed

Yamada, Aya; Futagi, Masaharu; Fukumoto, Emiko; Saito, Kan; Yoshizaki, Keigo; Ishikawa, Masaki; Arakaki, Makiko; Hino, Ryoko; Sugawara, Yu; Ishikawa, Momoko; Naruse, Masahiro; Miyazaki, Kanako; Nakamura, Takashi; Fukumoto, Satoshi

2016-01-08

Cell-cell interaction via the gap junction regulates cell growth and differentiation, leading to formation of organs of appropriate size and quality. To determine the role of connexin43 in salivary gland development, we analyzed its expression in developing submandibular glands (SMGs). Connexin43 (Cx43) was found to be expressed in salivary gland epithelium. In ex vivo organ cultures of SMGs, addition of the gap junctional inhibitors 18α-glycyrrhetinic acid (18α-GA) and oleamide inhibited SMG branching morphogenesis, suggesting that gap junctional communication contributes to salivary gland development. In Cx43(-/-) salivary glands, submandibular and sublingual gland size was reduced as compared with those from heterozygotes. The expression of Pdgfa, Pdgfb, Fgf7, and Fgf10, which induced branching of SMGs in Cx43(-/-) samples, were not changed as compared with those from heterozygotes. Furthermore, the blocking peptide for the hemichannel and gap junction channel showed inhibition of terminal bud branching. FGF10 induced branching morphogenesis, while it did not rescue the Cx43(-/-) phenotype, thus Cx43 may regulate FGF10 signaling during salivary gland development. FGF10 is expressed in salivary gland mesenchyme and regulates epithelial proliferation, and was shown to induce ERK1/2 phosphorylation in salivary epithelial cells, while ERK1/2 phosphorylation in HSY cells was dramatically inhibited by 18α-GA, a Cx43 peptide or siRNA. On the other hand, PDGF-AA and PDGF-BB separately induced ERK1/2 phosphorylation in primary cultured salivary mesenchymal cells regardless of the presence of 18α-GA. Together, our results suggest that Cx43 regulates FGF10-induced ERK1/2 phosphorylation in salivary epithelium but not in mesenchyme during the process of SMG branching morphogenesis. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Up-regulation of Wnt5a gene expression in the nitrofen-induced hypoplastic lung.

PubMed

Doi, Takashi; Puri, Prem

2009-12-01

The pathogenesis of pulmonary hypoplasia in nitrofen-induced congenital diaphragmatic hernia (CDH) still remains unclear. Wnt signaling pathways play a critical role in lung development. Whereas canonical Wnt signaling regulates branching morphogenesis during early lung development, the noncanonical Wnt5a controls late lung morphogenesis, including patterning of distal airway and vascular tubulogenesis (alveolarization). Overexpression of Wnt5a in transgenic mice and in the chick has been reported to result in severe pulmonary hypoplasia. We designed this study to test the hypothesis that the pulmonary Wnt5a gene expression is up-regulated in late stages of lung morphogenesis in CDH. Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). Fetal lungs were harvested on D15, D18, and D21 and divided into 3 groups: control; nitrofen without CDH, CDH(-); and nitrofen with CDH, CDH(+) (n = 8 at each time-point, respectively). Wnt5a pulmonary gene expression was analyzed by real-time reverse transcription polymerase chain reaction. Immunohistochemistry was performed to evaluate Wnt5a protein expression at each time-point. Pulmonary relative mRNA expression levels of Wnt5a were significantly increased in CDH(-) and CDH(+) at D18 (1.61 +/- 0.92 and 1.81 +/- 1.20, respectively) and D21 (2.40 +/- 0.74* and 2.65 +/- 0.35*, respectively) compared to controls at D18 and D21 (0.90 +/- 0.17* and 1.69 +/- 0.53**, respectively) (*P < .05, **P < .001 vs control ). Strong Wnt5a immunoreactivity was seen in the distal epithelium at D18 and D21 in nitrofen-induced hypoplastic lung compared to controls. Up-regulation of pulmonary Wnt5a gene expression in the late lung morphogenesis may interfere with patterning of alveolarization, causing pulmonary hypoplasia in the nitrofen-induced CDH.

Effect of cinnamomum zeylanicum blume essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species

PubMed Central

Carmo, Egberto Santos; de Oliveira Lima, Edeltrudes; de Souza, Evandro Leite; de Sousa, Frederico Barbosa

2008-01-01

Cinnamomum zeylanicum Blume is known for a wide range of medicinal properties. This study aimed to assess the interference of C. zeylanicum essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species. The essential oil presented strong antifungal effect causing the growth inhibition of the assayed strains and development of large growth inhibition zones. MIC50 and MIC90 values were 40 and 80 μL/mL, respectively. 80, 40 and 20 μL/mL of the oil strongly inhibited the radial mycelial growth of A. niger, A. flavus and A. fumigatus along 14 days. 80 and 40 μL/mL of the oil caused a 100% inhibition of the fungal spore germination. Main morphological changes observed under light microscopy provided by the essential oil in the fungal strains were decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure indicating fungal wall degeneration. It is concluded that C. zeylanicum essential oil could be known as potential antifungal compound, particularly, to protect against the growth of Aspergillus species. PMID:24031186

Time Course Exo-Metabolomic Profiling in the Green Marine Macroalga Ulva (Chlorophyta) for Identification of Growth Phase-Dependent Biomarkers

PubMed Central

Alsufyani, Taghreed; Weiss, Anne; Wichard, Thomas

2017-01-01

The marine green macroalga Ulva (Chlorophyta) lives in a mutualistic symbiosis with bacteria that influence growth, development, and morphogenesis. We surveyed changes in Ulva’s chemosphere, which was defined as a space where organisms interact with each other via compounds, such as infochemicals, nutrients, morphogens, and defense compounds. Thereby, Ulva mutabilis cooperates with bacteria, in particular, Roseovarius sp. strain MS2 and Maribacter sp. strain MS6 (formerly identified as Roseobacter sp. strain MS2 and Cytophaga sp. strain MS6). Without this accompanying microbial flora, U. mutabilis forms only callus-like colonies. However, upon addition of the two bacteria species, in effect forming a tripartite community, morphogenesis can be completely restored. Under this strictly standardized condition, bioactive and eco-physiologically-relevant marine natural products can be discovered. Solid phase extracted waterborne metabolites were analyzed using a metabolomics platform, facilitating gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) analysis, combined with the necessary acquisition of biological metadata. Multivariate statistics of the GC-MS and LC-MS data revealed strong differences between Ulva’s growth phases, as well as between the axenic Ulva cultures and the tripartite community. Waterborne biomarkers, including glycerol, were identified as potential indicators for algal carbon source and bacterial-algal interactions. Furthermore, it was demonstrated that U. mutabilis releases glycerol that can be utilized for growth by Roseovarius sp. MS2. PMID:28075408

[Molecular-biological properties of the rubella virus strains isolated in St. Petersburg].

PubMed

Buzitskaia, Zh V; Sirotkin, A K; Gudkova, T M; Prochukhanova, A P; Karpov, A V; Tsybalova, L M; Kiselev, O I

2012-01-01

In the surveillance of rubella in the northwest region of Russia samples of nasopharyngeal swabs from 37 patients with rubella, which were treated in the 442nd district military hospital named after Z.P. Solovyov in autumn 2007 were screened for the rubella virus using RK-13 cell line, 22 strains of rubella virus were isolated. Gene sequencing of E1 region of rubella virus isolates was carried out. Rubella virus strains isolated in St. Petersburg during the 2007 outbreak belonged to rubella virus genotype 1E. The morphogenesis of RK-13 cells with formation of replication complexes and enveloped virions of rubella virus was shown.

Genome-wide regulation of light-controlled seedling morphogenesis by three families of transcription factors.

PubMed

Shi, Hui; Lyu, Mohan; Luo, Yiwen; Liu, Shoucheng; Li, Yue; He, Hang; Wei, Ning; Deng, Xing Wang; Zhong, Shangwei

2018-06-19

Three families of transcription factors have been reported to play key roles in light control of Arabidopsis seedling morphogenesis. Among them, bHLH protein PIFs and plant-specific protein EIN3/EIN3-LIKE 1 (EIN3/EIL1) accumulate in the dark to maintain skotomorphogenesis. On the other hand, HY5 and HY5 HOMOLOG (HYH), two related bZIP proteins, are stabilized in light and promote photomorphogenic development. To systemically investigate the transcriptional regulation of light-controlled seedling morphogenesis, we generated HY5 ox/ pifQein3eil1 , which contained mutations of EIN3/EIL1 and four PIF genes ( pifQein3eil1 ) and overexpression of HY5 Our results show that dark-grown HY5 ox/ pifQein3eil1 seedlings display a photomorphogenesis highly similar to that of wild-type seedlings grown in continuous light, with remarkably enhanced photomorphogenic phenotypes compared with the pifQ mutants. Consistent with the genetic evidence, transcriptome analysis indicated that PIFs, EIN3/EIL1, and HY5 are dominant transcription factors in collectively mediating a wide range of light-caused genome-wide transcriptional changes. Moreover, PIFs and EIN3/EIL1 independently control the expression of light-regulated genes such as HLS1 to cooperatively regulate apical hook formation, hypocotyl elongation, and cotyledon opening and expansion. This study illustrates a comprehensive regulatory network of transcription activities that correspond to specific morphological aspects in seedling skotomorphogenesis and photomorphogenesis.

Macroalgal Morphogenesis Induced by Waterborne Compounds and Bacteria in Coastal Seawater

PubMed Central

Grueneberg, Jan; Engelen, Aschwin H.; Costa, Rodrigo; Wichard, Thomas

2016-01-01

Axenic gametes of the marine green macroalga Ulva mutabilis Føyn (Ria Formosa, locus typicus) exhibit abnormal development into slow-growing callus-like colonies with aberrant cell walls. Under laboratory conditions, it was previously demonstrated that all defects in growth and thallus development can be completely abolished when axenic gametes are inoculated with a combination of two specific bacterial strains originally identified as Roseobacter sp. strain MS2 and Cytophaga sp. strain MS6. These bacteria release diffusible morphogenetic compounds (= morphogens), which act similar to cytokinin and auxin. To investigate the ecological relevance of the waterborne bacterial morphogens, seawater samples were collected in the Ria Formosa lagoon (Algarve, Southern Portugal) at 20 sampling sites and tidal pools to assess their morphogenetic effects on the axenic gametes of U. mutabilis. Specifically the survey revealed that sterile-filtered seawater samples can completely recover growth and morphogenesis of U. mutabilis under axenic conditions. Morphogenetic activities of free-living and epiphytic bacteria isolated from the locally very abundant Ulva species (i.e., U. rigida) were screened using a multiwell-based testing system. The most represented genera isolated from U. rigida were Alteromonas, Pseudoalteromonas and Sulfitobacter followed by Psychrobacter and Polaribacter. Several naturally occurring bacterial species could emulate MS2 activity (= induction of cell divisions) regardless of taxonomic affiliation, whereas the MS6 activity (= induction of cell differentiation and cell wall formation) was species-specific and is probably a feature of difficult-to-culture bacteria. Interestingly, isolated bacteroidetes such as Algoriphagus sp. and Polaribacter sp. could individually trigger complete Ulva morphogenesis and thus provide a novel mode of action for bacterial-induced algal development. This study also highlights that the accumulation of algal growth factors in a shallow water body separated from the open ocean by barrier islands might have strong implications to, for example, the wide usage of natural coastal seawater in algal (land based) aquacultures of Ulva. PMID:26745366

Tissue organization by cadherin adhesion molecules: dynamic molecular and cellular mechanisms of morphogenetic regulation

PubMed Central

Niessen, Carien M.; Leckband, Deborah; Yap, Alpha S.

2013-01-01

This review addresses the cellular and molecular mechanisms of cadherin-based tissue morphogenesis. Tissue physiology is profoundly influenced by the distinctive organizations of cells in organs and tissues. In metazoa, adhesion receptors of the classical cadherin family play important roles in establishing and maintaining such tissue organization. Indeed, it is apparent that cadherins participate in a range of morphogenetic events that range from support of tissue integrity to dynamic cellular rearrangements. A comprehensive understanding of cadherin-based morphogenesis must then define the molecular and cellular mechanisms that support these distinct cadherin biologies. Here we focus on four key mechanistic elements: the molecular basis for adhesion through cadherin ectodomains; the regulation of cadherin expression at the cell surface; cooperation between cadherins and the actin cytoskeleton; and regulation by cell signaling. We discuss current progress and outline issues for further research in these fields. PMID:21527735

Mechanosensitivity of Jagged–Notch signaling can induce a switch-type behavior in vascular homeostasis

PubMed Central

Stassen, Oscar M. J. A.; ter Huurne, Fleur M.; Boareto, Marcelo; Sahlgren, Cecilia M.

2018-01-01

Hemodynamic forces and Notch signaling are both known as key regulators of arterial remodeling and homeostasis. However, how these two factors integrate in vascular morphogenesis and homeostasis is unclear. Here, we combined experiments and modeling to evaluate the impact of the integration of mechanics and Notch signaling on vascular homeostasis. Vascular smooth muscle cells (VSMCs) were cyclically stretched on flexible membranes, as quantified via video tracking, demonstrating that the expression of Jagged1, Notch3, and target genes was down-regulated with strain. The data were incorporated in a computational framework of Notch signaling in the vascular wall, where the mechanical load was defined by the vascular geometry and blood pressure. Upon increasing wall thickness, the model predicted a switch-type behavior of the Notch signaling state with a steep transition of synthetic toward contractile VSMCs at a certain transition thickness. These thicknesses varied per investigated arterial location and were in good agreement with human anatomical data, thereby suggesting that the Notch response to hemodynamics plays an important role in the establishment of vascular homeostasis. PMID:29610298

Inwardly rectifying potassium channels influence Drosophila wing morphogenesis by regulating Dpp release.

PubMed

Dahal, Giri Raj; Pradhan, Sarala Joshi; Bates, Emily Anne

2017-08-01

Loss of embryonic ion channel function leads to morphological defects, but the underlying reason for these defects remains elusive. Here, we show that inwardly rectifying potassium (Irk) channels regulate release of the Drosophila bone morphogenetic protein Dpp in the developing fly wing and that this is necessary for developmental signaling. Inhibition of Irk channels decreases the incidence of distinct Dpp-GFP release events above baseline fluorescence while leading to a broader distribution of Dpp-GFP. Work by others in different cell types has shown that Irk channels regulate peptide release by modulating membrane potential and calcium levels. We found calcium transients in the developing wing, and inhibition of Irk channels reduces the duration and amplitude of calcium transients. Depolarization with high extracellular potassium evokes Dpp release. Taken together, our data implicate Irk channels as a requirement for regulated release of Dpp, highlighting the importance of the temporal pattern of Dpp presentation for morphogenesis of the wing. © 2017. Published by The Company of Biologists Ltd.

An FGF autocrine loop initiated in second heart field mesoderm regulates morphogenesis at the arterial pole of the heart

PubMed Central

Park, Eon Joo; Watanabe, Yusuke; Smyth, Graham; Miyagawa-Tomita, Sachiko; Meyers, Erik; Klingensmith, John; Camenisch, Todd; Buckingham, Margaret; Moon, Anne M.

2009-01-01

In order to understand how secreted signals regulate complex morphogenetic events, it is crucial to identify their cellular targets. By conditional inactivation of Fgfr1 and Fgfr2 and overexpression of the FGF antagonist sprouty 2 in different cell types, we have dissected the role of FGF signaling during heart outflow tract development in mouse. Contrary to expectation, cardiac neural crest and endothelial cells are not primary paracrine targets. FGF signaling within second heart field mesoderm is required for remodeling of the outflow tract: when disrupted, outflow myocardium fails to produce extracellular matrix and TGFβ and BMP signals essential for endothelial cell transformation and invasion of cardiac neural crest. We conclude that an autocrine regulatory loop, initiated by the reception of FGF signals by the mesoderm, regulates correct morphogenesis at the arterial pole of the heart. These findings provide new insight into how FGF signaling regulates context-dependent cellular responses during development. PMID:18832392

Building Finite Element Models to Investigate Zebrafish Jaw Biomechanics.

PubMed

Brunt, Lucy H; Roddy, Karen A; Rayfield, Emily J; Hammond, Chrissy L

2016-12-03

Skeletal morphogenesis occurs through tightly regulated cell behaviors during development; many cell types alter their behavior in response to mechanical strain. Skeletal joints are subjected to dynamic mechanical loading. Finite element analysis (FEA) is a computational method, frequently used in engineering that can predict how a material or structure will respond to mechanical input. By dividing a whole system (in this case the zebrafish jaw skeleton) into a mesh of smaller 'finite elements', FEA can be used to calculate the mechanical response of the structure to external loads. The results can be visualized in many ways including as a 'heat map' showing the position of maximum and minimum principal strains (a positive principal strain indicates tension while a negative indicates compression. The maximum and minimum refer the largest and smallest strain). These can be used to identify which regions of the jaw and therefore which cells are likely to be under particularly high tensional or compressional loads during jaw movement and can therefore be used to identify relationships between mechanical strain and cell behavior. This protocol describes the steps to generate Finite Element models from confocal image data on the musculoskeletal system, using the zebrafish lower jaw as a practical example. The protocol leads the reader through a series of steps: 1) staining of the musculoskeletal components, 2) imaging the musculoskeletal components, 3) building a 3 dimensional (3D) surface, 4) generating a mesh of Finite Elements, 5) solving the FEA and finally 6) validating the results by comparison to real displacements seen in movements of the fish jaw.

Production of pigment-free pullulan by swollen cell in Aureobasidium pullulans NG which cell differentiation was affected by pH and nutrition.

PubMed

Li, Bing-xue; Zhang, Ning; Peng, Qing; Yin, Tie; Guan, Fei-fei; Wang, Gui-li; Li, Ying

2009-08-01

A black yeast strain "NG" was isolated from strawberry fruit and identified as Aureobasidium pullulans. Strain NG displayed yeast-like cell (YL), swollen cell (SC), septate swollen cell (SSC), meristematic structure (MS), and chlamydospore (CH) morphologies. pH was the key factor regulating cell morphogenesis of strain NG. Differentiation of YL controlled by extracellular pH had no relationship with nutrition level. YL was maintained at pH >6.0, but was transformed into SC at pH approximately 4.5. SC, a stable cell type of A. pullulans, could bud, septate, or transform into MS or CH, in response to nutrition level and low pH. SC produced swollen cell blastospores (SCB) at pH 2.1 with abundant nutrition, and could transform into MS at lower pH (1.5). SC was induced to form CH by low level nutrition and pH <3, and this transition was suppressed by adjusting pH to approximately 4.5. Crude polysaccharides without pigment (melanin) were produced by SC of strain NG. Pullulan content of the polysaccharides was very high (98.37%). Fourier-transform infrared spectroscopy confirmed that chemical structures of the polysaccharides and standard pullulan were identical. Swollen cells produced 2.08 mg/ml non-pigmented polysaccharides at 96 h in YPD medium. Controlling pH of fermentation is an effective and convenient method to harvest SC for melanin-free pullulan production.

Effect of different in vitro culture extracts of black pepper (Piper nigrum L.) on toxic metabolites-producing strains.

PubMed

Ahmad, Nisar; Abbasi, Bilal Haider; Fazal, Hina

2016-03-01

In the present study, the effect of different in vitro cultures (callus, in vitro shoots) and commercially available peppercorn extract was investigated for its activity against toxic metabolite-producing strains (Escherichia coli, Pseudomonas aeroginosa, Salmonella typhi, Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Candida albicans). These in vitro cultures were extracted with ethanol, hexane, and chloroform, and the antipathogenic activity was determined by well-diffusion method. Hexane extract of callus showed 22 mm zone of inhibition against B. cereus, 23 mm against S. aureus, while regenerated shoots and seeds have shown 24.3 and 26 mm zones of inhibition. The ethanolic extracts of regenerated Piper shoots have shown 25 mm activity against S. aureus, 21 mm against B. cereus, and 16 mm in the case of C. albicans in comparison with standard antibiotics. Peppercorn extracts in chloroform and ethanol had shown activities against B. cereus (23.6 mm) and B. subtilis (23.5 mm). During in vitro organogenesis and morphogenesis, cells and tissues produced a comparable phytochemicals profile like mother plant. Morphogenesis is critically controlled by the application of exogenous plant-growth regulators. Such addition alters the hormonal transduction pathways, and cells under in vitro conditions regenerate tissues, which are dependant on the physiological state of cells, and finally enhance the production of secondary metabolites. To the best of our knowledge, this is the first report to compare the antimicrobial potential of in vitro regenerated tissues and peppercorn with standard antibiotics. In conclusion, most of the extracts showed pronounced activities against all the pathogenic microbes. This is a preliminary work, and the minimum inhibitory concentration values needs to be further explored. Regenerated tissues of P. nigrum are a good source of biologically active metabolites for antimicrobial activities, and callus culture presented itself as a good candidate for such activities. © The Author(s) 2013.

Huntingtin Is Required for Epithelial Polarity through RAB11A-Mediated Apical Trafficking of PAR3-aPKC

PubMed Central

Elias, Salah; McGuire, John Russel; Yu, Hua; Humbert, Sandrine

2015-01-01

The establishment of apical-basolateral polarity is important for both normal development and disease, for example, during tumorigenesis and metastasis. During this process, polarity complexes are targeted to the apical surface by a RAB11A-dependent mechanism. Huntingtin (HTT), the protein that is mutated in Huntington disease, acts as a scaffold for molecular motors and promotes microtubule-based dynamics. Here, we investigated the role of HTT in apical polarity during the morphogenesis of the mouse mammary epithelium. We found that the depletion of HTT from luminal cells in vivo alters mouse ductal morphogenesis and lumen formation. HTT is required for the apical localization of PAR3-aPKC during epithelial morphogenesis in virgin, pregnant, and lactating mice. We show that HTT forms a complex with PAR3, aPKC, and RAB11A and ensures the microtubule-dependent apical vesicular translocation of PAR3-aPKC through RAB11A. We thus propose that HTT regulates polarized vesicular transport, lumen formation and mammary epithelial morphogenesis. PMID:25942483

The microRNA-200 family coordinately regulates cell adhesion and proliferation in hair morphogenesis.

PubMed

Hoefert, Jaimee E; Bjerke, Glen A; Wang, Dongmei; Yi, Rui

2018-06-04

The microRNA (miRNA)-200 (miR-200) family is highly expressed in epithelial cells and frequently lost in metastatic cancer. Despite intensive studies into their roles in cancer, their targets and functions in normal epithelial tissues remain unclear. Importantly, it remains unclear how the two subfamilies of the five-miRNA family, distinguished by a single nucleotide within the seed region, regulate their targets. By directly ligating miRNAs to their targeted mRNA regions, we identify numerous miR-200 targets involved in the regulation of focal adhesion, actin cytoskeleton, cell cycle, and Hippo/Yap signaling. The two subfamilies bind to largely distinct target sites, but many genes are coordinately regulated by both subfamilies. Using inducible and knockout mouse models, we show that the miR-200 family regulates cell adhesion and orientation in the hair germ, contributing to precise cell fate specification and hair morphogenesis. Our findings demonstrate that combinatorial targeting of many genes is critical for miRNA function and provide new insights into miR-200's functions. © 2018 Hoefert et al.

Mechanosensing of stem bending and its interspecific variability in five neotropical rainforest species.

PubMed

Coutand, Catherine; Chevolot, Malia; Lacointe, André; Rowe, Nick; Scotti, Ivan

2010-02-01

In rain forests, sapling survival is highly dependent on the regulation of trunk slenderness (height/diameter ratio): shade-intolerant species have to grow in height as fast as possible to reach the canopy but also have to withstand mechanical loadings (wind and their own weight) to avoid buckling. Recent studies suggest that mechanosensing is essential to control tree dimensions and stability-related morphogenesis. Differences in species slenderness have been observed among rainforest trees; the present study thus investigates whether species with different slenderness and growth habits exhibit differences in mechanosensitivity. Recent studies have led to a model of mechanosensing (sum-of-strains model) that predicts a quantitative relationship between the applied sum of longitudinal strains and the plant's responses in the case of a single bending. Saplings of five different neotropical species (Eperua falcata, E. grandiflora, Tachigali melinonii, Symphonia globulifera and Bauhinia guianensis) were subjected to a regimen of controlled mechanical loading phases (bending) alternating with still phases over a period of 2 months. Mechanical loading was controlled in terms of strains and the five species were subjected to the same range of sum of strains. The application of the sum-of-strain model led to a dose-response curve for each species. Dose-response curves were then compared between tested species. The model of mechanosensing (sum-of-strain model) applied in the case of multiple bending as long as the bending frequency was low. A comparison of dose-response curves for each species demonstrated differences in the stimulus threshold, suggesting two groups of responses among the species. Interestingly, the liana species B. guianensis exhibited a higher threshold than other Leguminosae species tested. This study provides a conceptual framework to study variability in plant mechanosensing and demonstrated interspecific variability in mechanosensing.

An integrated miRNA functional screening and target validation method for organ morphogenesis.

PubMed

Rebustini, Ivan T; Vlahos, Maryann; Packer, Trevor; Kukuruzinska, Maria A; Maas, Richard L

2016-03-16

The relative ease of identifying microRNAs and their increasing recognition as important regulators of organogenesis motivate the development of methods to efficiently assess microRNA function during organ morphogenesis. In this context, embryonic organ explants provide a reliable and reproducible system that recapitulates some of the important early morphogenetic processes during organ development. Here we present a method to target microRNA function in explanted mouse embryonic organs. Our method combines the use of peptide-based nanoparticles to transfect specific microRNA inhibitors or activators into embryonic organ explants, with a microRNA pulldown assay that allows direct identification of microRNA targets. This method provides effective assessment of microRNA function during organ morphogenesis, allows prioritization of multiple microRNAs in parallel for subsequent genetic approaches, and can be applied to a variety of embryonic organs.

JunB is required for endothelial cell morphogenesis by regulating core-binding factor β

PubMed Central

Licht, Alexander H.; Pein, Oliver T.; Florin, Lore; Hartenstein, Bettina; Reuter, Hendrik; Arnold, Bernd; Lichter, Peter; Angel, Peter; Schorpp-Kistner, Marina

2006-01-01

The molecular mechanism triggering the organization of endothelial cells (ECs) in multicellular tubules is mechanistically still poorly understood. We demonstrate that cell-autonomous endothelial functions of the AP-1 subunit JunB are required for proper endothelial morphogenesis both in vivo in mouse embryos with endothelial-specific ablation of JunB and in in vitro angiogenesis models. By cDNA microarray analysis, we identified core-binding factor β (CBFβ), which together with the Runx proteins forms the heterodimeric core-binding transcription complex CBF, as a novel JunB target gene. In line with our findings, expression of the CBF target MMP-13 was impaired in JunB-deficient ECs. Reintroduction of CBFβ into JunB-deficient ECs rescued the tube formation defect and MMP-13 expression, indicating an important role for CBFβ in EC morphogenesis. PMID:17158955

FOXA1 is an essential determinant of ERα expression and mammary ductal morphogenesis

PubMed Central

Bernardo, Gina M.; Lozada, Kristen L.; Miedler, John D.; Harburg, Gwyndolen; Hewitt, Sylvia C.; Mosley, Jonathan D.; Godwin, Andrew K.; Korach, Kenneth S.; Visvader, Jane E.; Kaestner, Klaus H.; Abdul-Karim, Fadi W.; Montano, Monica M.; Keri, Ruth A.

2010-01-01

FOXA1, estrogen receptor α (ERα) and GATA3 independently predict favorable outcome in breast cancer patients, and their expression correlates with a differentiated, luminal tumor subtype. As transcription factors, each functions in the morphogenesis of various organs, with ERα and GATA3 being established regulators of mammary gland development. Interdependency between these three factors in breast cancer and normal mammary development has been suggested, but the specific role for FOXA1 is not known. Herein, we report that Foxa1 deficiency causes a defect in hormone-induced mammary ductal invasion associated with a loss of terminal end bud formation and ERα expression. By contrast, Foxa1 null glands maintain GATA3 expression. Unlike ERα and GATA3 deficiency, Foxa1 null glands form milk-producing alveoli, indicating that the defect is restricted to expansion of the ductal epithelium, further emphasizing the novel role for FOXA1 in mammary morphogenesis. Using breast cancer cell lines, we also demonstrate that FOXA1 regulates ERα expression, but not GATA3. These data reveal that FOXA1 is necessary for hormonal responsiveness in the developing mammary gland and ERα-positive breast cancers, at least in part, through its control of ERα expression. PMID:20501593

Shavenbaby Couples Patterning to Epidermal Cell Shape Control

PubMed Central

Fernandes, Isabelle; Roch, Fernando; Payre, François

2006-01-01

It is well established that developmental programs act during embryogenesis to determine animal morphogenesis. How these developmental cues produce specific cell shape during morphogenesis, however, has remained elusive. We addressed this question by studying the morphological differentiation of the Drosophila epidermis, governed by a well-known circuit of regulators leading to a stereotyped pattern of smooth cells and cells forming actin-rich extensions (trichomes). It was shown that the transcription factor Shavenbaby plays a pivotal role in the formation of trichomes and underlies all examined cases of the evolutionary diversification of their pattern. To gain insight into the mechanisms of morphological differentiation, we sought to identify shavenbaby's downstream targets. We show here that Shavenbaby controls epidermal cell shape, through the transcriptional activation of different classes of cellular effectors, directly contributing to the organization of actin filaments, regulation of the extracellular matrix, and modification of the cuticle. Individual inactivation of shavenbaby's targets produces distinct trichome defects and only their simultaneous inactivation prevent trichome formation. Our data show that shavenbaby governs an evolutionarily conserved developmental module consisting of a set of genes collectively responsible for trichome formation, shedding new light on molecular mechanisms acting during morphogenesis and the way they can influence evolution of animal forms. PMID:16933974

Proinsulin in development: New roles for an ancient prohormone.

PubMed

Hernández-Sánchez, C; Mansilla, A; de la Rosa, E J; de Pablo, F

2006-06-01

In postnatal organisms, insulin is well known as an essential anabolic hormone responsible for maintaining glucose homeostasis. Its biosynthesis by the pancreatic beta cell has been considered a model of tissue-specific gene expression. However, proinsulin mRNA and protein have been found in embryonic stages before the formation of the pancreatic primordium, and later, in extrapancreatic tissues including the nervous system. Phylogenetic studies have also confirmed that production of insulin-like peptides antecedes the morphogenesis of a pancreas, and that these peptides contribute to normal development. In recent years, other roles for insulin distinct from its metabolic function have emerged also in vertebrates. During embryonic development, insulin acts as a survival factor and is involved in early morphogenesis. These findings are consistent with the observation that, at these stages, the proinsulin gene product remains as the precursor form, proinsulin. Independent of its low metabolic activity, proinsulin stimulates proliferation in developing neuroretina, as well as cell survival and cardiogenesis in early embryos. Insulin/proinsulin levels are finely regulated during development, since an excess of the protein interferes with correct morphogenesis and is deleterious for the embryo. This fine-tuned regulation is achieved by the expression of alternative embryonic proinsulin transcripts that have diminished translational activity.

Epithelial junction formation requires confinement of Cdc42 activity by a novel SH3BP1 complex

PubMed Central

Elbediwy, Ahmed; Zihni, Ceniz; Terry, Stephen J.; Clark, Peter

2012-01-01

Epithelial cell–cell adhesion and morphogenesis require dynamic control of actin-driven membrane remodeling. The Rho guanosine triphosphatase (GTPase) Cdc42 regulates sequential molecular processes during cell–cell junction formation; hence, mechanisms must exist that inactivate Cdc42 in a temporally and spatially controlled manner. In this paper, we identify SH3BP1, a GTPase-activating protein for Cdc42 and Rac, as a regulator of junction assembly and epithelial morphogenesis using a functional small interfering ribonucleic acid screen. Depletion of SH3BP1 resulted in loss of spatial control of Cdc42 activity, stalled membrane remodeling, and enhanced growth of filopodia. SH3BP1 formed a complex with JACOP/paracingulin, a junctional adaptor, and CD2AP, a scaffolding protein; both were required for normal Cdc42 signaling and junction formation. The filamentous actin–capping protein CapZ also associated with the SH3BP1 complex and was required for control of actin remodeling. Epithelial junction formation and morphogenesis thus require a dual activity complex, containing SH3BP1 and CapZ, that is recruited to sites of active membrane remodeling to guide Cdc42 signaling and cytoskeletal dynamics. PMID:22891260

Dynamic formation of microenvironments at the myotendinous junction correlates with muscle fiber morphogenesis in zebrafish

PubMed Central

Snow, Chelsi J.; Henry, Clarissa A.

2009-01-01

Muscle development involves the specification and morphogenesis of muscle fibers that attach to tendons. After attachment, muscles and tendons then function as an integrated unit to transduce force to the skeletal system and stabilize joints. The attachment site is the myotendinous junction, or MTJ, and is the primary site of force transmission. We find that attachment of fast-twitch myofibers to the MTJ correlates with the formation of novel microenvironments within the MTJ. The expression or activation of two proteins involved in anchoring the intracellular cytoskeleton to the extracellular matrix, Focal adhesion kinase (Fak) and β-dystroglycan is up-regulated. Conversely, the extracellular matrix protein Fibronectin (Fn) is down-regulated. This degradation of Fn as fast-twitch fibers attach to the MTJ results in Fn protein defining a novel microenvironment within the MTJ adjacent to slow-twitch, but not fast-twitch, muscle. Interestingly, however, Fak, laminin, Fn and β-dystroglycan concentrate at the MTJ in mutants that do not have slow-twitch fibers. Taken together, these data elucidate novel and dynamic microenvironments within the MTJ and indicate that MTJ morphogenesis is spatially and temporally complex. PMID:18783736

The APC tumor suppressor is required for epithelial cell polarization and three-dimensional morphogenesis

PubMed Central

Lesko, Alyssa C.; Goss, Kathleen H.; Yang, Frank F.; Schwertner, Adam; Hulur, Imge; Onel, Kenan; Prosperi, Jenifer R.

2015-01-01

The Adenomatous Polyposis Coli (APC) tumor suppressor has been previously implicated in the control of apical-basal polarity; yet, the consequence of APC loss-of-function in epithelial polarization and morphogenesis has not been characterized. To test the hypothesis that APC is required for the establishment of normal epithelial polarity and morphogenesis programs, we generated APC-knockdown epithelial cell lines. APC depletion resulted in loss of polarity and multi-layering on permeable supports, and enlarged, filled spheroids with disrupted polarity in 3D culture. Importantly, these effects of APC knockdown were independent of Wnt/β-catenin signaling, but were rescued with either full-length or a carboxy (c)-terminal segment of APC. Moreover, we identified a gene expression signature associated with APC knockdown that points to several candidates known to regulate cell-cell and cell-matrix communication. Analysis of epithelial tissues from mice and humans carrying heterozygous APC mutations further support the importance of APC as a regulator of epithelial behavior and tissue architecture. These data also suggest that the initiation of epithelial-derived tumors as a result of APC mutation or gene silencing may be driven by loss of polarity and dysmorphogenesis. PMID:25578398

Genome-Wide Transcriptional Profiling Reveals Two Distinct Outcomes in Central Nervous System Infections of Rabies Virus.

PubMed

Zhang, Daiting; He, Feilong; Bi, Shuilian; Guo, Huixia; Zhang, Baoshi; Wu, Fan; Liang, Jiaqi; Yang, Youtian; Tian, Qin; Ju, Chunmei; Fan, Huiying; Chen, Jinding; Guo, Xiaofeng; Luo, Yongwen

2016-01-01

Rabies remains a major public health concern in many developing countries. The precise neuropathogenesis of rabies is unknown, though it is hypothesized to be due to neuronal death or dysfunction. Mice that received intranasal inoculation of an attenuated rabies virus (RABV) strain HEP-Flury exhibited subtle clinical signs, and eventually recovered, which is different from the fatal encephalitis caused by the virulent RABV strain CVS-11. To understand the neuropathogenesis of rabies and the mechanisms of viral clearance, we applied RNA sequencing (RNA-Seq) to compare the brain transcriptomes of normal mice vs. HEP-Flury or CVS-11 intranasally inoculated mice. Our results revealed that both RABV strains altered positively and negatively the expression levels of many host genes, including genes associated with innate and adaptive immunity, inflammation and cell death. It is found that HEP-Flury infection can activate the innate immunity earlier through the RIG-I/MDA-5 signaling, and the innate immunity pre-activated by HEP-Flury or Newcastle disease virus (NDV) infection can effectively prevent the CVS-11 to invade central nervous system (CNS), but fails to clear the CVS-11 after its entry into the CNS. In addition, following CVS-11 infection, genes implicated in cell adhesion, blood vessel morphogenesis and coagulation were mainly up-regulated, while the genes involved in synaptic transmission and ion transport were significantly down-regulated. On the other hand, several genes involved in the MHC class II-mediated antigen presentation pathway were activated to a greater extent after the HEP-Flury infection as compared with the CVS-11 infection suggesting that the collaboration of CD4(+) T cells and MHC class II-mediated antigen presentation is critical for the clearance of attenuated RABV from the CNS. The differentially regulated genes reported here are likely to include potential therapeutic targets for expanding the post-exposure treatment window for RABV infection.

MoSET1 (Histone H3K4 Methyltransferase in Magnaporthe oryzae) Regulates Global Gene Expression during Infection-Related Morphogenesis

PubMed Central

Pham, Kieu Thi Minh; Inoue, Yoshihiro; Vu, Ba Van; Nguyen, Hanh Hieu; Nakayashiki, Toru; Ikeda, Ken-ichi; Nakayashiki, Hitoshi

2015-01-01

Here we report the genetic analyses of histone lysine methyltransferase (KMT) genes in the phytopathogenic fungus Magnaporthe oryzae. Eight putative M. oryzae KMT genes were targeted for gene disruption by homologous recombination. Phenotypic assays revealed that the eight KMTs were involved in various infection processes at varying degrees. Moset1 disruptants (Δmoset1) impaired in histone H3 lysine 4 methylation (H3K4me) showed the most severe defects in infection-related morphogenesis, including conidiation and appressorium formation. Consequently, Δmoset1 lost pathogenicity on wheat host plants, thus indicating that H3K4me is an important epigenetic mark for infection-related gene expression in M. oryzae. Interestingly, appressorium formation was greatly restored in the Δmoset1 mutants by exogenous addition of cAMP or of the cutin monomer, 16-hydroxypalmitic acid. The Δmoset1 mutants were still infectious on the super-susceptible barley cultivar Nigrate. These results suggested that MoSET1 plays roles in various aspects of infection, including signal perception and overcoming host-specific resistance. However, since Δmoset1 was also impaired in vegetative growth, the impact of MoSET1 on gene regulation was not infection specific. ChIP-seq analysis of H3K4 di- and tri-methylation (H3K4me2/me3) and MoSET1 protein during infection-related morphogenesis, together with RNA-seq analysis of the Δmoset1 mutant, led to the following conclusions: 1) Approximately 5% of M. oryzae genes showed significant changes in H3K4-me2 or -me3 abundance during infection-related morphogenesis. 2) In general, H3K4-me2 and -me3 abundance was positively associated with active transcription. 3) Lack of MoSET1 methyltransferase, however, resulted in up-regulation of a significant portion of the M. oryzae genes in the vegetative mycelia (1,491 genes), and during infection-related morphogenesis (1,385 genes), indicating that MoSET1 has a role in gene repression either directly or more likely indirectly. 4) Among the 4,077 differentially expressed genes (DEGs) between mycelia and germination tubes, 1,201 and 882 genes were up- and down-regulated, respectively, in a Moset1-dependent manner. 5) The Moset1-dependent DEGs were enriched in several gene categories such as signal transduction, transport, RNA processing, and translation. PMID:26230995

On the genetic control of planar growth during tissue morphogenesis in plants.

PubMed

Enugutti, Balaji; Kirchhelle, Charlotte; Schneitz, Kay

2013-06-01

Tissue morphogenesis requires extensive intercellular communication. Plant organs are composites of distinct radial cell layers. A typical layer, such as the epidermis, is propagated by stereotypic anticlinal cell divisions. It is presently unclear what mechanisms coordinate cell divisions relative to the plane of a layer, resulting in planar growth and maintenance of the layer structure. Failure in the regulation of coordinated growth across a tissue may result in spatially restricted abnormal growth and the formation of a tumor-like protrusion. Therefore, one way to approach planar growth control is to look for genetic mutants that exhibit localized tumor-like outgrowths. Interestingly, plants appear to have evolved quite robust genetic mechanisms that govern these aspects of tissue morphogenesis. Here we provide a short summary of the current knowledge about the genetics of tumor formation in plants and relate it to the known control of coordinated cell behavior within a tissue layer. We further portray the integuments of Arabidopsis thaliana as an excellent model system to study the regulation of planar growth. The value of examining this process in integuments was established by the recent identification of the Arabidopsis AGC VIII kinase UNICORN as a novel growth suppressor involved in the regulation of planar growth and the inhibition of localized ectopic growth in integuments and other floral organs. An emerging insight is that misregulation of central determinants of adaxial-abaxial tissue polarity can lead to the formation of spatially restricted multicellular outgrowths in several tissues. Thus, there may exist a link between the mechanisms regulating adaxial-abaxial tissue polarity and planar growth in plants.

Mechanical Modulation of Nascent Stem Cell Lineage Commitment in Tissue Engineering Scaffolds

PubMed Central

Song, Min Jae; Dean, David; Tate, Melissa L. Knothe

2013-01-01

Taking inspiration from tissue morphogenesis in utero, this study tests the concept of using tissue engineering scaffolds as delivery devices to modulate emergent structure-function relationships at early stages of tissue genesis. We report on the use of a combined computational fluid dynamics (CFD) modeling, advanced manufacturing methods, and experimental fluid mechanics (micro-piv and strain mapping) for the prospective design of tissue engineering scaffold geometries that deliver spatially resolved mechanical cues to cells seeded within. When subjected to a constant magnitude global flow regime, the local scaffold geometry dictates the magnitudes of mechanical stresses and strains experienced by a given cell, and in a spatially resolved fashion, similar to patterning during morphogenesis. In addition, early markers of mesenchymal stem cell lineage commitment relate significantly to the local mechanical environment of the cell. Finally, by plotting the range of stress-strain states for all data corresponding to nascent cell lineage commitment (95% CI), we begin to “map the mechanome”, defining stress-strain states most conducive to targeted cell fates. In sum, we provide a library of reference mechanical cues that can be delivered to cells seeded on tissue engineering scaffolds to guide target tissue phenotypes in a temporally and spatially resolved manner. Knowledge of these effects allows for prospective scaffold design optimization using virtual models prior to prototyping and clinical implementation. Finally, this approach enables the development of next generation scaffolds cum delivery devices for genesis of complex tissues with heterogenous properties, e.g., organs, joints or interface tissues such as growth plates. PMID:23660249

Mechanical modulation of nascent stem cell lineage commitment in tissue engineering scaffolds.

PubMed

Song, Min Jae; Dean, David; Knothe Tate, Melissa L

2013-07-01

Taking inspiration from tissue morphogenesis in utero, this study tests the concept of using tissue engineering scaffolds as delivery devices to modulate emergent structure-function relationships at early stages of tissue genesis. We report on the use of a combined computational fluid dynamics (CFD) modeling, advanced manufacturing methods, and experimental fluid mechanics (micro-piv and strain mapping) for the prospective design of tissue engineering scaffold geometries that deliver spatially resolved mechanical cues to stem cells seeded within. When subjected to a constant magnitude global flow regime, the local scaffold geometry dictates the magnitudes of mechanical stresses and strains experienced by a given cell, and in a spatially resolved fashion, similar to patterning during morphogenesis. In addition, early markers of mesenchymal stem cell lineage commitment relate significantly to the local mechanical environment of the cell. Finally, by plotting the range of stress-strain states for all data corresponding to nascent cell lineage commitment (95% CI), we begin to "map the mechanome", defining stress-strain states most conducive to targeted cell fates. In sum, we provide a library of reference mechanical cues that can be delivered to cells seeded on tissue engineering scaffolds to guide target tissue phenotypes in a temporally and spatially resolved manner. Knowledge of these effects allows for prospective scaffold design optimization using virtual models prior to prototyping and clinical implementation. Finally, this approach enables the development of next generation scaffolds cum delivery devices for genesis of complex tissues with heterogenous properties, e.g., organs, joints or interface tissues such as growth plates. Copyright © 2013 Elsevier Ltd. All rights reserved.

WNTLESS IS REQUIRED FOR PERIPHERAL LUNG DIFFERENTIATION AND PULMONARY VASCULAR DEVELOPMENT

PubMed Central

Cornett, Bridget; Snowball, John; Varisco, Brian M.; Lang, Richard; Whitsett, Jeffrey; Sinner, Debora

2013-01-01

Wntless (Wls), a gene highly conserved across the animal kingdom, encodes for a transmembrane protein that mediates Wnt ligand secretion. Wls is expressed in developing lung, wherein Wnt signaling is necessary for pulmonary morphogenesis. We hypothesize that Wls plays a critical role in modulating Wnt signaling during lung development and therefore affects processes critical for pulmonary morphogenesis. We generated conditional Wls mutant mice utilizing Shh-Cre and Dermo1-Cre mice to delete Wls in the embryonic respiratory epithelium and mesenchyme, respectively. Epithelial deletion of Wls disrupted lung branching morphogenesis, peripheral lung development and pulmonary endothelial differentiation. Epithelial Wls mutant mice died at birth due to respiratory failure caused by lung hypoplasia and pulmonary hemorrhage. In the lungs of these mice, VEGF and Tie2-angiopoietin signaling pathways, which mediate vascular development, were downregulated from early stages of development. In contrast, deletion of Wls in mesenchymal cells of the developing lung did not alter branching morphogenesis or early mesenchymal differentiation. In vitro assays support the concept that Wls acts in part via Wnt5a to regulate pulmonary vascular development. We conclude that epithelial Wls modulates Wnt ligand activities critical for pulmonary vascular differentiation and peripheral lung morphogenesis. These studies provide a new framework for understanding the molecular mechanisms underlying normal pulmonary vasculature formation and the dysmorphic pulmonary vasculature development associated with congenital lung disease. PMID:23523683

Wntless is required for peripheral lung differentiation and pulmonary vascular development.

PubMed

Cornett, Bridget; Snowball, John; Varisco, Brian M; Lang, Richard; Whitsett, Jeffrey; Sinner, Debora

2013-07-01

Wntless (Wls), a gene highly conserved across the animal kingdom, encodes for a transmembrane protein that mediates Wnt ligand secretion. Wls is expressed in developing lung, wherein Wnt signaling is necessary for pulmonary morphogenesis. We hypothesize that Wls plays a critical role in modulating Wnt signaling during lung development and therefore affects processes critical for pulmonary morphogenesis. We generated conditional Wls mutant mice utilizing Shh-Cre and Dermo1-Cre mice to delete Wls in the embryonic respiratory epithelium and mesenchyme, respectively. Epithelial deletion of Wls disrupted lung branching morphogenesis, peripheral lung development and pulmonary endothelial differentiation. Epithelial Wls mutant mice died at birth due to respiratory failure caused by lung hypoplasia and pulmonary hemorrhage. In the lungs of these mice, VEGF and Tie2-angiopoietin signaling pathways, which mediate vascular development, were downregulated from early stages of development. In contrast, deletion of Wls in mesenchymal cells of the developing lung did not alter branching morphogenesis or early mesenchymal differentiation. In vitro assays support the concept that Wls acts in part via Wnt5a to regulate pulmonary vascular development. We conclude that epithelial Wls modulates Wnt ligand activities critical for pulmonary vascular differentiation and peripheral lung morphogenesis. These studies provide a new framework for understanding the molecular mechanisms underlying normal pulmonary vasculature formation and the dysmorphic pulmonary vasculature development associated with congenital lung disease. Copyright © 2013 Elsevier Inc. All rights reserved.

Mechanical Influences on Morphogenesis of the Knee Joint Revealed through Morphological, Molecular and Computational Analysis of Immobilised Embryos

PubMed Central

Roddy, Karen A.; Prendergast, Patrick J.; Murphy, Paula

2011-01-01

Very little is known about the regulation of morphogenesis in synovial joints. Mechanical forces generated from muscle contractions are required for normal development of several aspects of normal skeletogenesis. Here we show that biophysical stimuli generated by muscle contractions impact multiple events during chick knee joint morphogenesis influencing differential growth of the skeletal rudiment epiphyses and patterning of the emerging tissues in the joint interzone. Immobilisation of chick embryos was achieved through treatment with the neuromuscular blocking agent Decamethonium Bromide. The effects on development of the knee joint were examined using a combination of computational modelling to predict alterations in biophysical stimuli, detailed morphometric analysis of 3D digital representations, cell proliferation assays and in situ hybridisation to examine the expression of a selected panel of genes known to regulate joint development. This work revealed the precise changes to shape, particularly in the distal femur, that occur in an altered mechanical environment, corresponding to predicted changes in the spatial and dynamic patterns of mechanical stimuli and region specific changes in cell proliferation rates. In addition, we show altered patterning of the emerging tissues of the joint interzone with the loss of clearly defined and organised cell territories revealed by loss of characteristic interzone gene expression and abnormal expression of cartilage markers. This work shows that local dynamic patterns of biophysical stimuli generated from muscle contractions in the embryo act as a source of positional information guiding patterning and morphogenesis of the developing knee joint. PMID:21386908

Regulation of lung branching morphogenesis by bombesin-like peptides and neutral endopeptidase.

PubMed

Aguayo, S M; Schuyler, W E; Murtagh, J J; Roman, J

1994-06-01

The expression of bombesin-like peptides (BLPs) by pulmonary neuroendocrine cells is transiently upregulated during lung development. A functional role for BLPs is supported by their ability to stimulate lung growth and maturation both in vitro and in vivo during the late stages of lung development. In addition, the cell membrane-associated enzyme CD10/neutral endopeptidase 24.11 (CD10/NEP), which inactivates BLPs and other regulatory peptides, is also expressed by developing lungs and modulates the stimulatory effects of BLPs on lung growth and maturation. We hypothesized that, in addition to expressing BLPs and CD10/NEP, embryonic lungs must express BLP receptors, and that BLPs may also regulate processes that occur during early lung development such as branching morphogenesis. Using reverse transcriptase-polymerase chain reaction and oligonucleotide primers designed for amplifying a BLP receptor originally isolated from Swiss 3T3 mouse fibroblasts, we found that embryonic mouse lungs express a similar BLP receptor mRNA during the pseudoglandular stage of lung development when branching morphogenesis take place. Subsequently, we evaluated the effects of ligands for this BLP receptor using embryonic mouse lungs in an in vitro model of lung branching morphogenesis. We found that, in comparison with control lungs, treatment with bombesin (1 to 100 nM) resulted in a modest increase in clefts or branching points. In contrast, embryonic mouse lungs treated with the BLP analog [Leu13-psi(CH2NH)Leu14]bombesin (1 microM), which also binds to this BLP receptor but has predominantly antagonistic effects, demonstrated fewer branching points.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcription Factors Runx1 to 3 Are Expressed in the Lacrimal Gland Epithelium and Are Involved in Regulation of Gland Morphogenesis and Regeneration

PubMed Central

Voronov, Dmitry; Gromova, Anastasia; Liu, Daren; Zoukhri, Driss; Medvinsky, Alexander; Meech, Robyn; Makarenkova, Helen P.

2013-01-01

Purpose. Lacrimal gland (LG) morphogenesis and repair are regulated by a complex interplay of intrinsic factors (e.g., transcription factors) and extrinsic signals (e.g., soluble growth/signaling factors). Many of these interconnections remain poorly characterized. Runt-related (Runx) factors belong to a small family of heterodimeric transcription factors known to regulate lineage-specific proliferation and differentiation of stem cells. The purpose of this study was to define the expression pattern and the role of Runx proteins in LG development and regeneration. Methods. Expression of epithelial-restricted transcription factors in murine LG was examined using immunostaining, qRT-PCR, and RT2Profiler PCR microarrays. The role of Runx transcription factors in LG morphogenesis was studied using siRNA and ex vivo LG cultures. Expression of Runx transcription factors during LG regeneration was assessed using in vivo model of LG regeneration. Results. We found that Runx factors are expressed in the epithelial compartment of the LG; in particular, Runx1 was restricted to the epithelium with highest level of expression in ductal and centroacinar cells. Downregulation of Runx1 to 3 expression using Runx-specific siRNAs abolished LG growth and branching and our data suggest that Runx1, 2, and 3 are partially redundant in LG development. In siRNA-treated LG, reduction of branching correlated with reduction of epithelial proliferation, as well as expression of cyclin D1 and the putative epithelial progenitor cell marker cytokeratin-5. Runx1, Runx3, and cytokeratin-5 expression increased significantly in regenerating LG and there was modest increase in Runx2 expression during LG differentiation. Conclusions. Runx1 and 2 are new markers of the LG epithelial lineage and Runx factors are important for normal LG morphogenesis and regeneration. PMID:23532528

Mechanical Control of Tissue Morphogenesis

PubMed Central

Patwari, Parth; Lee, Richard T.

2008-01-01

Mechanical forces participate in morphogenesis from the level of individual cells to whole organism patterning. This manuscript reviews recent research that has identified specific roles for mechanical forces in important developmental events. One well-defined example is that dynein-driven cilia create fluid flow that determines left-right patterning in the early mammalian embryo. Fluid flow is also important for vasculogenesis, and evidence suggests that fluid shear stress rather than fluid transport is primarily required for remodeling the early vasculature. Contraction of the actin cytoskeleton, driven by nonmuscle myosins and regulated by the Rho family GTPases, is a recurring mechanism for controlling morphogenesis throughout development, from gastrulation to cardiogenesis. Finally, novel experimental approaches suggest critical roles for the actin cytoskeleton and the mechanical environment in determining differentiation of mesenchymal stem cells. Insights into the mechanisms linking mechanical forces to cell and tissue differentiation pathways are important for understanding many congenital diseases and for developing regenerative medicine strategies. PMID:18669930

Transcriptional regulation of neuronal polarity and morphogenesis in the mammalian brain

PubMed Central

de la Torre-Ubieta, Luis; Bonni, Azad

2012-01-01

The highly specialized morphology of a neuron, typically consisting of a long axon and multiple branching dendrites, lies at the core of the principle of dynamic polarization, whereby information flows from dendrites toward the soma and to the axon. For more than a century neuroscientists have been fascinated by how shape is important for neuronal function and how neurons acquire their characteristic morphology. During the past decade, substantial progress has been made in our understanding of the molecular underpinnings of neuronal polarity and morphogenesis. In these studies, transcription factors have emerged as key players governing multiple aspects of neuronal morphogenesis from neuronal polarization and migration to axon growth and pathfinding to dendrite growth and branching to synaptogenesis. In this review, we will highlight the role of transcription factors in shaping neuronal morphology with emphasis on recent literature in mammalian systems. PMID:21982366

MicroRNAs and the Evolution of Insect Metamorphosis.

PubMed

Belles, Xavier

2017-01-31

MicroRNAs (miRNAs) are involved in the regulation of a number of processes associated with metamorphosis, either in the less modified hemimetabolan mode or in the more modified holometabolan mode. The miR-100/let-7/miR-125 cluster has been studied extensively, especially in relation to wing morphogenesis in both hemimetabolan and holometabolan species. Other miRNAs also participate in wing morphogenesis, as well as in programmed cell and tissue death, neuromaturation, neuromuscular junction formation, and neuron cell fate determination, typically during the pupal stage of holometabolan species. A special case is the control of miR-2 over Kr-h1 transcripts, which determines adult morphogenesis in the hemimetabolan metamorphosis. This is an elegant example of how a single miRNA can control an entire process by acting on a crucial mediator; however, this is a quite exceptional mechanism that was apparently lost during the transition from hemimetaboly to holometaboly.

Engineering Three-dimensional Epithelial Tissues Embedded within Extracellular Matrix.

PubMed

Piotrowski-Daspit, Alexandra S; Nelson, Celeste M

2016-07-10

The architecture of branched organs such as the lungs, kidneys, and mammary glands arises through the developmental process of branching morphogenesis, which is regulated by a variety of soluble and physical signals in the microenvironment. Described here is a method created to study the process of branching morphogenesis by forming engineered three-dimensional (3D) epithelial tissues of defined shape and size that are completely embedded within an extracellular matrix (ECM). This method enables the formation of arrays of identical tissues and enables the control of a variety of environmental factors, including tissue geometry, spacing, and ECM composition. This method can also be combined with widely used techniques such as traction force microscopy (TFM) to gain more information about the interactions between cells and their surrounding ECM. The protocol can be used to investigate a variety of cell and tissue processes beyond branching morphogenesis, including cancer invasion.

A Transient Exposure to Symbiosis-Competent Bacteria Induces Light Organ Morphogenesis in the Host Squid.

PubMed

Doino, J A; McFall-Ngai, M J

1995-12-01

Recent studies of the symbiotic association between the Hawaiian sepiolid squid Euprymna scolopes and the luminous bacterium Vibrio fischeri have shown that colonization of juvenile squid with symbiosis-competent bacteria induces morphogenetic changes of the light organ. These changes occur over a 4-day period and include cell death and tissue regression of the external ciliated epithelium. In the absence of bacterial colonization, morphogenesis does not occur. To determine whether the bacteria must be present throughout the morphogenetic process, we used the antibiotic chloramphenicol to clear the light organ of bacteria at various times during the initial colonization. We provide evidence in this study that a transient, 12-hour exposure to symbiosis-competent bacteria is necessary and sufficient to induce tissue regression in the light organ over the next several days. Further, we show that successful entrance into the light organ is necessary to induce morphogenesis, suggesting that induction results from bacterial interaction with internal crypt cells and not with the external ciliated epithelium. Finally, no difference in development was observed when the light organ was colonized by a mutant strain of V. fischeri that did not produce autoinducer, a potential light organ morphogen.

A bacteriophage for Myxococcus xanthus: isolation, characterization and relation of infectivity to host morphogenesis.

PubMed

Burchard, R P; Dworkin, M

1966-03-01

Burchard, Robert P. (University of Minnesota, Minneapolis), and M. Dworkin. A bacteriophage for Myxococcus xanthus: isolation, characterization and relation of infectivity to host morphogenesis. J. Bacteriol. 91:1305-1313. 1966.-A bacteriophage (MX-1) infecting Myxococcus xanthus FB(t) has been isolated from cow dung. The bacteriophage particle is approximately 175 mmu long. A tail about 100 mmu in length is encased in a contractile sheath and terminates in a tail plate. The head is polyhedral with a width of about 75 mmu. The nucleic acid of the bacteriophage is deoxyribonucleic acid and has a guanine plus cytosine content of 55.5%. The bacteriophage requires 10(-3)m Ca(++) and 10(-2)m monovalent cation for optimal adsorption. Grown on vegetative cells of M. xanthus FB(t) at 30 C in 2% Casitone medium, the bacteriophage has a latent period of 120 min and a burst size of approximately 100. Host range studies indicate that three strains of M. xanthus including a morphogenetic mutant are sensitive to the bacteriophage, whereas M. fulvus, Cytophaga, Sporocytophaga myxococcoides, and a fourth strain of M. xanthus are not. Of the two cellular forms characteristic of the Myxococcus life cycle, the bacteriophage infect only the vegetative cells; they do not adsorb to microcysts. Ability to adsorb bacteriophage is lost between 65 and 75 min after initiation of the relatively synchronous conversion of vegetative cells to microcysts. The bacteriophage does not adsorb to spheroplasts. After the appearance of visible morphogenesis and before the loss of bacteriophage receptor sites, addition of bacteriophage results in the formation of microcysts which give rise to infective centers only upon germination. The possibility that the infected microcysts are harboring intact bacteriophages has been eliminated.

Drosophila Activin- and the Activin-like product Dawdle function redundantly to regulate proliferation in the larval brain.

PubMed

Zhu, Changqi C; Boone, Jason Q; Jensen, Philip A; Hanna, Scott; Podemski, Lynn; Locke, John; Doe, Chris Q; O'Connor, Michael B

2008-02-01

The Drosophila Activin-like ligands Activin-beta and Dawdle control several aspects of neuronal morphogenesis, including mushroom body remodeling, dorsal neuron morphogenesis and motoneuron axon guidance. Here we show that the same two ligands act redundantly through the Activin receptor Babo and its transcriptional mediator Smad2 (Smox), to regulate neuroblast numbers and proliferation rates in the developing larval brain. Blocking this pathway results in the development of larvae with small brains and aberrant photoreceptor axon targeting, and restoring babo function in neuroblasts rescued these mutant phenotypes. These results suggest that the Activin signaling pathway is required for producing the proper number of neurons to enable normal connection of incoming photoreceptor axons to their targets. Furthermore, as the Activin pathway plays a key role in regulating propagation of mouse and human embryonic stem cells, our observation that it also regulates neuroblast numbers and proliferation in Drosophila suggests that involvement of Activins in controlling stem cell propagation may be a common regulatory feature of this family of TGF-beta-type ligands.

Transcriptional regulation of fksA, a β-1,3-glucan synthase gene, by the APSES protein StuA during Aspergillus nidulans development.

PubMed

Park, Bum-Chan; Park, Yun-Hee; Yi, Soohyun; Choi, Yu Kyung; Kang, Eun-Hye; Park, Hee-Moon

2014-11-01

The temporal and spatial regulation of β-1,3-glucan synthesis plays an important role in morphogenesis during fungal growth and development. Northern blot analysis showed that the transcription of fksA, the gene encoding β-1,3-glucan synthase in Aspergillus nidulans, was cell-cycle-dependent and increased steadily over the duration of the vegetative period, but its overall expression during the asexual and sexual stages was fairly constant up until the time of transcription cessation. In an A. nidulans strain mutated in the eukaryotic bHLH-like APSES transcription factor stuA1, the transcriptional level of fksA, and consequently the content of alkali-insoluble cell wall β-glucan, significantly increased at the conidial chain formation and maturation stage. Electrophoretic mobility shift assays revealed that StuA was bound to StREs (StuA Response Elements) on the fksA promoter region. Promoter analysis with sGFP-fusion constructs also indicated the negative regulation of fksA expression by StuA, especially during asexual development. Taken together, these data suggest that StuA plays an important role in cell wall biogenesis during the development of A. nidulans, by controlling the transcription level of fksA.

Light and electron microscope study of the neurotropism of Powassan virus strain P-40.

PubMed

Isachkova, L M; Shestopalova, N M; Frolova, M P; Reingold, V N

1979-01-01

Brains of adult white mice inoculated with the P-40 strain of Powassan virus isolated in Primorsky Krai (U.S.S.R) from ticks were studied by light and electron microscopy. Accumulations of virus particles were found in neurons and their dendrites and axons, in glial cells, and in intercellular spaces. In the nerve cells, most prevalent were changes of the type of chromatolysis and formation of small vacuoles, associated with the alteration of the endoplasmic reticulum induced by virus morphogenesis. In virus-affected cells, multilayer dense membranes were found.

E3 ubiquitin ligase RFWD2 controls lung branching through protein-level regulation of ETV transcription factors.

PubMed

Zhang, Yan; Yokoyama, Shigetoshi; Herriges, John C; Zhang, Zhen; Young, Randee E; Verheyden, Jamie M; Sun, Xin

2016-07-05

The mammalian lung is an elaborate branching organ, and it forms following a highly stereotypical morphogenesis program. It is well established that precise control at the transcript level is a key genetic underpinning of lung branching. In comparison, little is known about how regulation at the protein level may play a role. Ring finger and WD domain 2 (RFWD2, also termed COP1) is an E3 ubiquitin ligase that modifies specific target proteins, priming their degradation via the ubiquitin proteasome system. RFWD2 is known to function in the adult in pathogenic processes such as tumorigenesis. Here, we show that prenatal inactivation of Rfwd2 gene in the lung epithelium led to a striking halt in branching morphogenesis shortly after secondary branch formation. This defect is accompanied by distalization of the lung epithelium while growth and cellular differentiation still occurred. In the mutant lung, two E26 transformation-specific (ETS) transcription factors essential for normal lung branching, ETS translocation variant 4 (ETV4) and ETV5, were up-regulated at the protein level, but not at the transcript level. Introduction of Etv loss-of-function alleles into the Rfwd2 mutant background attenuated the branching phenotype, suggesting that RFWD2 functions, at least in part, through degrading ETV proteins. Because a number of E3 ligases are known to target factors important for lung development, our findings provide a preview of protein-level regulatory network essential for lung branching morphogenesis.

Expression Pattern of the Pro-apoptotic Gene PAR-4 During the Morphogenesis of MCF-10A Human Mammary Epithelial Cells.

PubMed

de Bessa Garcia, Simone A; Pereira, Michelly C; Nagai, Maria A

2010-12-21

The histological organization of the mammary gland involves a spatial interaction of epithelial and myoepithelial cells with the specialized basement membrane (BM), composed of extra-cellular matrix (ECM) proteins, which is disrupted during the tumorigenic process. The interactions between mammary epithelial cells and ECM components play a major role in mammary gland branching morphogenesis. Critical signals for mammary epithelial cell proliferation, differentiation, and survival are provided by the ECM proteins. Three-dimensional (3D) cell culture was developed to establish a system that simulates several features of the breast epithelium in vivo; 3D cell culture of the spontaneously immortalized cell line, MCF10A, is a well-established model system to study breast epithelial cell biology and morphogenesis. Mammary epithelial cells grown in 3D form spheroids, acquire apicobasal polarization, and form lumens that resemble acini structures, processes that involve cell death. Using this system, we evaluated the expression of the pro-apoptotic gene PAWR (PKC apoptosis WT1 regulator; also named PAR-4, prostate apoptosis response-4) by immunofluorescence and quantitative real time PCR (qPCR). A time-dependent increase in PAR-4 mRNA expression was found during the process of MCF10A acinar morphogenesis. Confocal microscopy analysis also showed that PAR-4 protein was highly expressed in the MCF10A cells inside the acini structure. During the morphogenesis of MCF10A cells in 3D cell culture, the cells within the lumen showed caspase-3 activation, indicating apoptotic activity. PAR-4 was only partially co-expressed with activated caspase-3 on these cells. Our results provide evidence, for the first time, that PAR-4 is differentially expressed during the process of MCF10A acinar morphogenesis.

Tight Control of Trehalose Content Is Required for Efficient Heat-induced Cell Elongation in Candida albicans*

PubMed Central

Serneels, Joke; Tournu, Hélène; Van Dijck, Patrick

2012-01-01

The ability to form hyphae in the human pathogenic fungus Candida albicans is a prerequisite for virulence. It contributes to tissue infection, biofilm formation, as well as escape from phagocytes. Cell elongation triggered by human body temperature involves the essential heat shock protein Hsp90, which negatively governs a filamentation program dependent upon the Ras-protein kinase A (PKA) pathway. Tight regulation of Hsp90 function is required to ensure fast appropriate response and maintenance of a wide range of regulatory and signaling proteins. Client protein activation by Hsp90 relies on a conformational change of the chaperone, whose ATPase activity is competitively inhibited by geldanamycin. We demonstrate a novel regulatory mechanism of heat- and Hsp90-dependent induced morphogenesis, whereby the nonreducing disaccharide trehalose acts as a negative regulator of Hsp90 release. By means of a mutant strain deleted for Gpr1, the G protein-coupled receptor upstream of PKA, we demonstrate that elevated trehalose content in that strain, resulting from misregulation of enzymatic activities involved in trehalose metabolism, disrupts the filamentation program in response to heat. Addition of geldanamycin does not result in hyphal extensions at 30 °C in the gpr1Δ/gpr1Δ mutant as it does in wild type cells. In addition, validamycin, a specific inhibitor of trehalase, the trehalose-degrading enzyme, inhibits cell elongation in response to heat and geldanamycin. These results place Gpr1 as a regulator of trehalose metabolism in C. albicans and illustrate that trehalose modulates Hsp90-dependent activation of client proteins and signaling pathways leading to filamentation in the human fungal pathogen. PMID:22952228

The phosphorylated C-terminus of cAR1 plays a role in cell-type-specific gene expression and STATa tyrosine phosphorylation.

PubMed

Briscoe, C; Moniakis, J; Kim, J Y; Brown, J M; Hereld, D; Devreotes, P N; Firtel, R A

2001-05-01

cAMP receptors mediate some signaling pathways via coupled heterotrimeric G proteins, while others are G-protein-independent. This latter class includes the activation of the transcription factors GBF and STATa. Within the cellular mounds formed by aggregation of Dictyostelium, micromolar levels of cAMP activate GBF function, thereby inducing the transcription of postaggregative genes and initiating multicellular differentiation. Activation of STATa, a regulator of culmination and ecmB expression, results from cAMP receptor-dependent tyrosine phosphorylation and nuclear localization, also in mound-stage cells. During mound development, the cAMP receptor cAR1 is in a low-affinity state and is phosphorylated on multiple serine residues in its C-terminus. This paper addresses possible roles of cAMP receptor phosphorylation in the cAMP-mediated stimulation of GBF activity, STATa tyrosine phosphorylation, and cell-type-specific gene expression. To accomplish this, we have expressed cAR1 mutants in a strain in which the endogenous cAMP receptors that mediate postaggregative gene expression in vivo are deleted. We then examined the ability of these cells to undergo morphogenesis and induce postaggregative and cell-type-specific gene expression and STATa tyrosine phosphorylation. Analysis of cAR1 mutants in which the C-terminal tail is deleted or the ligand-mediated phosphorylation sites are mutated suggests that the cAR1 C-terminus is not essential for GBF-mediated postaggregative gene expression or STATa tyrosine phosphorylation, but may play a role in regulating cell-type-specific gene expression and morphogenesis. A mutant receptor, in which the C-terminal tail is constitutively phosphorylated, exhibits constitutive activation of STATa tyrosine phosphorylation in pulsed cells in suspension and a significantly impaired ability to induce cell-type-specific gene expression. The constitutively phosphorylated receptor also exerts a partial dominant negative effect on multicellular development when expressed in wild-type cells. These findings suggest that the phosphorylated C-terminus of cAR1 may be involved in regulating aspects of receptor-mediated processes, is not essential for GBF function, and may play a role in mediating subsequent development. Copyright 2001 Academic Press.

Cellular context–mediated Akt dynamics regulates MAP kinase signaling thresholds during angiogenesis

PubMed Central

Hellesøy, Monica; Lorens, James B.

2015-01-01

The formation of new blood vessels by sprouting angiogenesis is tightly regulated by contextual cues that affect angiogeneic growth factor signaling. Both constitutive activation and loss of Akt kinase activity in endothelial cells impair angiogenesis, suggesting that Akt dynamics mediates contextual microenvironmental regulation. We explored the temporal regulation of Akt in endothelial cells during formation of capillary-like networks induced by cell–cell contact with vascular smooth muscle cells (vSMCs) and vSMC-associated VEGF. Expression of constitutively active Akt1 strongly inhibited network formation, whereas hemiphosphorylated Akt1 epi-alleles with reduced kinase activity had an intermediate inhibitory effect. Conversely, inhibition of Akt signaling did not affect endothelial cell migration or morphogenesis in vSMC cocultures that generate capillary-like structures. We found that endothelial Akt activity is transiently blocked by proteasomal degradation in the presence of SMCs during the initial phase of capillary-like structure formation. Suppressed Akt activity corresponded to the increased endothelial MAP kinase signaling that was required for angiogenic endothelial morphogenesis. These results reveal a regulatory principle by which cellular context regulates Akt protein dynamics, which determines MAP kinase signaling thresholds necessary drive a morphogenetic program during angiogenesis. PMID:26023089

Proteome Analysis Unravels Mechanism Underling the Embryogenesis of the Honeybee Drone and Its Divergence with the Worker (Apis mellifera lingustica).

PubMed

Fang, Yu; Feng, Mao; Han, Bin; Qi, Yuping; Hu, Han; Fan, Pei; Huo, Xinmei; Meng, Lifeng; Li, Jianke

2015-09-04

The worker and drone bees each contain a separate diploid and haploid genetic makeup, respectively. Mechanisms regulating the embryogenesis of the drone and its mechanistic difference with the worker are still poorly understood. The proteomes of the two embryos at three time-points throughout development were analyzed by applying mass spectrometry-based proteomics. We identified 2788 and 2840 proteins in the worker and drone embryos, respectively. The age-dependent proteome driving the drone embryogenesis generally follows the worker's. The two embryos however evolve a distinct proteome setting to prime their respective embryogenesis. The strongly expressed proteins and pathways related to transcriptional-translational machinery and morphogenesis at 24 h drone embryo relative to the worker, illustrating the earlier occurrence of morphogenesis in the drone than worker. These morphogenesis differences remain through to the middle-late stage in the two embryos. The two embryos employ distinct antioxidant mechanisms coinciding with the temporal-difference organogenesis. The drone embryo's strongly expressed cytoskeletal proteins signify key roles to match its large body size. The RNAi induced knockdown of the ribosomal protein offers evidence for the functional investigation of gene regulating of honeybee embryogenesis. The data significantly expand novel regulatory mechanisms governing the embryogenesis, which is potentially important for honeybee and other insects.

Extensive Use of RNA-Binding Proteins in Drosophila Sensory Neuron Dendrite Morphogenesis

PubMed Central

Olesnicky, Eugenia C.; Killian, Darrell J.; Garcia, Evelyn; Morton, Mary C.; Rathjen, Alan R.; Sola, Ismail E.; Gavis, Elizabeth R.

2013-01-01

The large number of RNA-binding proteins and translation factors encoded in the Drosophila and other metazoan genomes predicts widespread use of post-transcriptional regulation in cellular and developmental processes. Previous studies identified roles for several RNA-binding proteins in dendrite branching morphogenesis of Drosophila larval sensory neurons. To determine the larger contribution of post-transcriptional gene regulation to neuronal morphogenesis, we conducted an RNA interference screen to identify additional Drosophila proteins annotated as either RNA-binding proteins or translation factors that function in producing the complex dendritic trees of larval class IV dendritic arborization neurons. We identified 88 genes encoding such proteins whose knockdown resulted in aberrant dendritic morphology, including alterations in dendritic branch number, branch length, field size, and patterning of the dendritic tree. In particular, splicing and translation initiation factors were associated with distinct and characteristic phenotypes, suggesting that different morphogenetic events are best controlled at specific steps in post-transcriptional messenger RNA metabolism. Many of the factors identified in the screen have been implicated in controlling the subcellular distributions and translation of maternal messenger RNAs; thus, common post-transcriptional regulatory strategies may be used in neurogenesis and in the generation of asymmetry in the female germline and embryo. PMID:24347626

CPK3-phosphorylated RhoGDI1 is essential in the development of Arabidopsis seedlings and leaf epidermal cells

PubMed Central

Wu, Yan

2013-01-01

The regulation of Rho of plants (ROP) in morphogenesis of leaf epidermal cells has been well studied, but the roles concerning regulators of ROPs such as RhoGDIs are poorly understood. This study reports that AtRhoGDI1 (GDI1) acts as a versatile regulator to modulate development of seedlings and leaf pavement cells. In mutant gdi1, leaf pavement cells showed shorter lobes in comparison with those in wild type. In GDI1-14 seedlings (GDI1-overexpression line) the growth of lobes in pavement cells was severely suppressed and the development of seedlings was altered. These results indicate that GDI1 plays an essential role in morphogenesis of epidermal pavement cells through modulating the ROP signalling pathways. The interaction between GDI1 and ROP2 or ROP6 was detected in the leaf pavement cells using FRET analysis. Dominant negative, not constitutively active, DN-rop6 could weaken the effect caused by overexpression of GDI1; because the pleiotropic phenotype of GDI1-14 plants was eliminated in the hybrid line GDI1-14 DN-rop6. GDI1 could be phosphorylated by CPK3. Three conserved Ser/Thr residues in GDI1 were determined as targeted amino acids for CPK3. Overexpression of GDI1(3D), not GDI1(3A), could rescue the abnormal growth phenotypes of gdi1-1 seedlings, demonstrating the impact of GDI1 phosphorylation in the development of Arabidopsis. In summary, these results suggest that GDI1 regulation in morphogenesis of seedlings and leaf pavement cells could be undergone through modulating the ROP signalling pathways and the phosphorylation of GDI1 by CPK3 was required for the developmental modulation in Arabidopsis. PMID:23846874

High sequence variations in the region containing genes encoding a cellular morphogenesis protein and the repressor of sexual development help to reveal origins of Aspergillus oryzae

USDA-ARS?s Scientific Manuscript database

Aspergillus oryzae and Aspergillus flavus are closely related fungal species. The A. flavus population that produces numerous small sclerotia (S strain) and aflatoxin has a unique 1.5 kb deletion in the norB-cypA region of the aflatoxin gene cluster (the S genotype). Phylogenetic studies have indica...

Cell Cycle Dynamics and Quorum Sensing in Candida albicans Chlamydospores Are Distinct from Budding and Hyphal Growth

PubMed Central

Martin, Stephen W.; Douglas, Lois M.; Konopka, James B.

2005-01-01

The regulation of morphogenesis in the human fungal pathogen Candida albicans is under investigation to better understand how the switch between budding and hyphal growth is linked to virulence. Therefore, in this study we examined the ability of C. albicans to undergo a distinct type of morphogenesis to form large thick-walled chlamydospores whose role in infection is unclear, but they act as a resting form in other species. During chlamydospore morphogenesis, cells switch to filamentous growth and then develop elongated suspensor cells that give rise to chlamydospores. These filamentous cells were distinct from true hyphae in that they were wider and were not inhibited by the quorum-sensing factor farnesol. Instead, farnesol increased chlamydospore production, indicating that quorum sensing can also have a positive role. Nuclear division did not occur across the necks of chlamydospores, as it does in budding. Interestingly, nuclei divided within the suspensor cells, and then one daughter nucleus subsequently migrated into the chlamydospore. Septins were not detected near mitotic nuclei but were localized at chlamydospore necks. At later stages, septins localized throughout the chlamydospore plasma membrane and appeared to form long filamentous structures. Deletion of the CDC10 or CDC11 septins caused greater curvature of cells growing in a filamentous manner and morphological defects in suspensor cells and chlamydospores. These studies identify aspects of chlamydospore morphogenesis that are distinct from bud and hyphal morphogenesis. PMID:16002645

hmmr mediates anterior neural tube closure and morphogenesis in the frog Xenopus.

PubMed

Prager, Angela; Hagenlocher, Cathrin; Ott, Tim; Schambony, Alexandra; Feistel, Kerstin

2017-10-01

Development of the central nervous system requires orchestration of morphogenetic processes which drive elevation and apposition of the neural folds and their fusion into a neural tube. The newly formed tube gives rise to the brain in anterior regions and continues to develop into the spinal cord posteriorly. Conspicuous differences between the anterior and posterior neural tube become visible already during neural tube closure (NTC). Planar cell polarity (PCP)-mediated convergent extension (CE) movements are restricted to the posterior neural plate, i.e. hindbrain and spinal cord, where they propagate neural fold apposition. The lack of CE in the anterior neural plate correlates with a much slower mode of neural fold apposition anteriorly. The morphogenetic processes driving anterior NTC have not been addressed in detail. Here, we report a novel role for the breast cancer susceptibility gene and microtubule (MT) binding protein Hmmr (Hyaluronan-mediated motility receptor, RHAMM) in anterior neurulation and forebrain development in Xenopus laevis. Loss of hmmr function resulted in a lack of telencephalic hemisphere separation, arising from defective roof plate formation, which in turn was caused by impaired neural tissue narrowing. hmmr regulated polarization of neural cells, a function which was dependent on the MT binding domains. hmmr cooperated with the core PCP component vangl2 in regulating cell polarity and neural morphogenesis. Disrupted cell polarization and elongation in hmmr and vangl2 morphants prevented radial intercalation (RI), a cell behavior essential for neural morphogenesis. Our results pinpoint a novel role of hmmr in anterior neural development and support the notion that RI is a major driving force for anterior neurulation and forebrain morphogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Neural crest development and craniofacial morphogenesis is coordinated by nitric oxide and histone acetylation

PubMed Central

Kong, Yawei; Grimaldi, Michael; Curtin, Eugene; Dougherty, Max; Kaufman, Charles; White, Richard M.; Zon, Leonard I.; Liao, Eric C.

2015-01-01

Cranial neural crest (CNC) cells are patterned and coalesce to facial prominences that undergo convergence and extension to generate the craniofacial form. We applied a chemical genetics approach to identify pathways that regulate craniofacial development during embryogenesis. Treatment with the nitric oxide synthase inhibitor TRIM abrogated first pharyngeal arch structures and induced ectopic ceratobranchial formation. TRIM promoted a progenitor CNC fate and inhibited chondrogenic differentiation, which were mediated through impaired nitric oxide (NO) production without appreciable effect on global protein S-nitrosylation. Instead, TRIM perturbed hox gene patterning and caused histone hypoacetylation. Rescue of TRIM phenotype was achieved with over-expression of histone acetyltransferase kat6a, inhibition of histone deacetylase, and complimentary NO. These studies demonstrate that NO signaling and histone acetylation are coordinated mechanisms that regulate CNC patterning, differentiation and convergence during craniofacial morphogenesis. PMID:24684905

TDZ pulsing evaluation on the in vitro morphogenesis of peach palm.

PubMed

Graner, Erika Mendes; Oberschelp, Gustavo Pedro Javier; Brondani, Gilvano Ebling; Batagin-Piotto, Katherine Derlene; de Almeida, Cristina Vieira; de Almeida, Marcílio

2013-04-01

Peach palm (Bactris gasipaes Kunth.) cropping is an excellent alternative to native species exploitation; nevertheless, the problems with seed germination and conventional propagation justify the use of in vitro culturing. Aiming to asses TDZ pulsing effect on B. gasipaes morphogenesis, explants obtained from unarmed microplants were maintained in two treatments, half of them in MS free medium (without growth regulator) and the other half in MS with TDZ (0.36 μM). Both groups were transferred to growth regulator-free MS medium following 14 days of culture. After 84 days of culture, TDZ pulsing increased the growth and development of the shoots, restricted the growth and development of the roots, with no influence on adventitious bud induction or somatic embryogenesis. Furthermore, development of prickles, thickening of roots and chlorotic leaves were noted under TDZ pulsing. Leaf sheath histological analysis showed an epidermal origin and no vascularization of these prickles.

Dynamic expression of a Hydra FGF at boundaries and termini.

PubMed

Lange, Ellen; Bertrand, Stephanie; Holz, Oliver; Rebscher, Nicole; Hassel, Monika

2014-12-01

Guidance of cells and tissue sheets is an essential function in developing and differentiating animal tissues. In Hydra, where cells and tissue move dynamically due to constant cell proliferation towards the termini or into lateral, vegetative buds, factors essential for guidance are still unknown. Good candidates to take over this function are fibroblast growth factors (FGFs). We present the phylogeny of several Hydra FGFs and analysis of their expression patterns. One of the FGFs is expressed in all terminal regions targeted by tissue movement and at boundaries crossed by moving tissue and cells with an expression pattern slightly differing in two Hydra strains. A model addressing an involvement of this FGF in cell movement and morphogenesis is proposed: Hydra FGFf-expressing cells might serve as sources to attract tissue and cells towards the termini of the body column and across morphological boundaries. Moreover, a function in morphogenesis and/or differentiation of cells and tissue is suggested.

The mechanics of development: models and methods for tissue morphogenesis

PubMed Central

Gjorevski, Nikolce; Nelson, Celeste M.

2011-01-01

Embryonic development is a physical process during which masses of cells are sculpted into functional organs. The mechanical properties of tissues and the forces exerted on them serve as epigenetic regulators of morphogenesis. Understanding these mechanobiological effects in the embryo requires new experimental approaches. Here we focus on branching of the lung airways and bending of the heart tube to describe examples of mechanical and physical cues that guide cell fate decisions and organogenesis. We highlight recent technological advances to measure tissue elasticity and endogenous mechanical stresses in real time during organ development. We also discuss recent progress in manipulating forces in intact embryos. PMID:20860059

Spatial mapping and quantification of developmental branching morphogenesis.

PubMed

Short, Kieran; Hodson, Mark; Smyth, Ian

2013-01-15

Branching morphogenesis is a fundamental developmental mechanism that shapes the formation of many organs. The complex three-dimensional shapes derived by this process reflect equally complex genetic interactions between branching epithelia and their surrounding mesenchyme. Despite the importance of this process to normal adult organ function, analysis of branching has been stymied by the absence of a bespoke method to quantify accurately the complex spatial datasets that describe it. As a consequence, although many developmentally important genes are proposed to influence branching morphogenesis, we have no way of objectively assessing their individual contributions to this process. We report the development of a method for accurately quantifying many aspects of branching morphogenesis and we demonstrate its application to the study of organ development. As proof of principle we have employed this approach to analyse the developing mouse lung and kidney, describing the spatial characteristics of the branching ureteric bud and pulmonary epithelia. To demonstrate further its capacity to profile unrecognised genetic contributions to organ development, we examine Tgfb2 mutant kidneys, identifying elements of both developmental delay and specific spatial dysmorphology caused by haplo-insufficiency for this gene. This technical advance provides a crucial resource that will enable rigorous characterisation of the genetic and environmental factors that regulate this essential and evolutionarily conserved developmental mechanism.

Hedgehog Is a Positive Regulator of FGF Signalling during Embryonic Tracheal Cell Migration

PubMed Central

Butí, Elisenda; Mesquita, Duarte; Araújo, Sofia J.

2014-01-01

Cell migration is a widespread and complex process that is crucial for morphogenesis and for the underlying invasion and metastasis of human cancers. During migration, cells are steered toward target sites by guidance molecules that induce cell direction and movement through complex intracellular mechanisms. The spatio-temporal regulation of the expression of these guidance molecules is of extreme importance for both normal morphogenesis and human disease. One way to achieve this precise regulation is by combinatorial inputs of different transcription factors. Here we used Drosophila melanogaster mutants with migration defects in the ganglionic branches of the tracheal system to further clarify guidance regulation during cell migration. By studying the cellular consequences of overactivated Hh signalling, using ptc mutants, we found that Hh positively regulates Bnl/FGF levels during embryonic stages. Our results show that Hh modulates cell migration non-autonomously in the tissues surrounding the action of its activity. We further demonstrate that the Hh signalling pathway regulates bnl expression via Stripe (Sr), a zinc-finger transcription factor with homology to the Early Growth Response (EGR) family of vertebrate transcription factors. We propose that Hh modulates embryonic cell migration by participating in the spatio-temporal regulation of bnl expression in a permissive mode. By doing so, we provide a molecular link between the activation of Hh signalling and increased chemotactic responses during cell migration. PMID:24651658

Hedgehog is a positive regulator of FGF signalling during embryonic tracheal cell migration.

PubMed

Butí, Elisenda; Mesquita, Duarte; Araújo, Sofia J

2014-01-01

Cell migration is a widespread and complex process that is crucial for morphogenesis and for the underlying invasion and metastasis of human cancers. During migration, cells are steered toward target sites by guidance molecules that induce cell direction and movement through complex intracellular mechanisms. The spatio-temporal regulation of the expression of these guidance molecules is of extreme importance for both normal morphogenesis and human disease. One way to achieve this precise regulation is by combinatorial inputs of different transcription factors. Here we used Drosophila melanogaster mutants with migration defects in the ganglionic branches of the tracheal system to further clarify guidance regulation during cell migration. By studying the cellular consequences of overactivated Hh signalling, using ptc mutants, we found that Hh positively regulates Bnl/FGF levels during embryonic stages. Our results show that Hh modulates cell migration non-autonomously in the tissues surrounding the action of its activity. We further demonstrate that the Hh signalling pathway regulates bnl expression via Stripe (Sr), a zinc-finger transcription factor with homology to the Early Growth Response (EGR) family of vertebrate transcription factors. We propose that Hh modulates embryonic cell migration by participating in the spatio-temporal regulation of bnl expression in a permissive mode. By doing so, we provide a molecular link between the activation of Hh signalling and increased chemotactic responses during cell migration.

Microfluidic chest cavities reveal that transmural pressure controls the rate of lung development.

PubMed

Nelson, Celeste M; Gleghorn, Jason P; Pang, Mei-Fong; Jaslove, Jacob M; Goodwin, Katharine; Varner, Victor D; Miller, Erin; Radisky, Derek C; Stone, Howard A

2017-12-01

Mechanical forces are increasingly recognized to regulate morphogenesis, but how this is accomplished in the context of the multiple tissue types present within a developing organ remains unclear. Here, we use bioengineered 'microfluidic chest cavities' to precisely control the mechanical environment of the fetal lung. We show that transmural pressure controls airway branching morphogenesis, the frequency of airway smooth muscle contraction, and the rate of developmental maturation of the lungs, as assessed by transcriptional analyses. Time-lapse imaging reveals that branching events are synchronized across distant locations within the lung, and are preceded by long-duration waves of airway smooth muscle contraction. Higher transmural pressure decreases the interval between systemic smooth muscle contractions and increases the rate of morphogenesis of the airway epithelium. These data reveal that the mechanical properties of the microenvironment instruct crosstalk between different tissues to control the development of the embryonic lung. © 2017. Published by The Company of Biologists Ltd.

Context clues: the importance of stem cell-material interactions

PubMed Central

Murphy, William L.

2014-01-01

Understanding the processes by which stem cells give rise to de novo tissues is an active focus of stem cell biology and bioengineering disciplines. Instructive morphogenic cues surrounding the stem cell during morphogenesis create what is referred to as the stem cell microenvironment. An emerging paradigm in stem cell bioengineering involves “biologically driven assembly,” in which stem cells are encouraged to largely define their own morphogenesis processes. However, even in the case of biologically driven assembly, stem cells do not act alone. The properties of the surrounding microenvironment can be critical regulators of cell fate. Stem cell-material interactions are among the most well-characterized microenvironmental effectors of stem cell fate, and they establish a signaling “context” that can define the mode of influence for morphogenic cues. Here we describe illustrative examples of cell-material interactions that occur during in vitro stem cell studies, with an emphasis on how cell-material interactions create instructive contexts for stem cell differentiation and morphogenesis. PMID:24369691

Unified quantitative characterization of epithelial tissue development

PubMed Central

Guirao, Boris; Rigaud, Stéphane U; Bosveld, Floris; Bailles, Anaïs; López-Gay, Jesús; Ishihara, Shuji; Sugimura, Kaoru

2015-01-01

Understanding the mechanisms regulating development requires a quantitative characterization of cell divisions, rearrangements, cell size and shape changes, and apoptoses. We developed a multiscale formalism that relates the characterizations of each cell process to tissue growth and morphogenesis. Having validated the formalism on computer simulations, we quantified separately all morphogenetic events in the Drosophila dorsal thorax and wing pupal epithelia to obtain comprehensive statistical maps linking cell and tissue scale dynamics. While globally cell shape changes, rearrangements and divisions all significantly participate in tissue morphogenesis, locally, their relative participations display major variations in space and time. By blocking division we analyzed the impact of division on rearrangements, cell shape changes and tissue morphogenesis. Finally, by combining the formalism with mechanical stress measurement, we evidenced unexpected interplays between patterns of tissue elongation, cell division and stress. Our formalism provides a novel and rigorous approach to uncover mechanisms governing tissue development. DOI: http://dx.doi.org/10.7554/eLife.08519.001 PMID:26653285

Macroalgal-bacterial interactions: Role of dimethylsulfoniopropionate in microbial gardening by Ulva (Chlorophyta).

PubMed

Kessler, Ralf W; Weiss, Anne; Kuegler, Stefan; Hermes, Cornelia; Wichard, Thomas

2018-04-01

The marine macroalga Ulva mutabilis (Chlorophyta) develops into callus-like colonies consisting of undifferentiated cells and abnormal cell walls under axenic conditions. Ulva mutabilis is routinely cultured with two bacteria, the Roseovarius sp. MS2 strain and the Maribacter sp. MS6 strain, which release morphogenetic compounds and ensure proper algal morphogenesis. Using this tripartite community as an emerging model system, we tested the hypothesis that the bacterial-algal interactions evolved as a result of mutually taking advantage of signals in the environment. Our study aimed to determine whether cross-kingdom crosstalk is mediated by the attraction of bacteria through algal chemotactic signals. Roseovarius sp. MS2 senses the known osmolyte dimethylsulfoniopropionate (DMSP) released by Ulva into the growth medium. Roseovarius sp. is attracted by DMSP and takes it up rapidly such that DMSP can only be determined in axenic growth media. As DMSP did not promote bacterial growth under the tested conditions, Roseovarius benefited solely from glycerol as the carbon source provided by Ulva. Roseovarius quickly catabolized DMSP into methanethiol (MeSH) and dimethylsulphide (DMS). We conclude that many bacteria can use DMSP as a reliable signal indicating a food source and promote the subsequent development and morphogenesis in Ulva. © 2017 John Wiley & Sons Ltd.

Regulation of Embryonic and Postnatal Development by the CSF-1 Receptor

PubMed Central

Chitu, Violeta; Stanley, E. Richard

2017-01-01

Macrophages are found in all tissues and regulate tissue morphogenesis during development through trophic and scavenger functions. The colony stimulating factor-1 (CSF-1) receptor (CSF-1R) is the major regulator of tissue macrophage development and maintenance. In combination with receptor activator of nuclear factor κB (RANK), the CSF-1R also regulates the differentiation of the bone-resorbing osteoclast and controls bone remodeling during embryonic and early postnatal development. CSF-1R-regulated macrophages play trophic and remodeling roles in development. Outside the mononuclear phagocytic system, the CSF-1R directly regulates neuronal survival and differentiation, the development of intestinal Paneth cells and of preimplantation embryos, as well as trophoblast innate immune function. Consistent with the pleiotropic roles of the receptor during development, CSF-1R deficiency in most mouse strains causes embryonic or perinatal death and the surviving mice exhibit multiple developmental and functional deficits. The CSF-1R is activated by two dimeric glycoprotein ligands, CSF-1, and interleukin-34 (IL-34). Homozygous Csf1-null mutations phenocopy most of the deficits of Csf1r-null mice. In contrast, Il34-null mice have no gross phenotype, except for decreased numbers of Langerhans cells and microglia, indicating that CSF-1 plays the major developmental role. Homozygous inactivating mutations of the Csf1r or its ligands have not been reported in man. However, heterozygous inactivating mutations in the Csf1r lead to a dominantly inherited adult-onset progressive dementia, highlighting the importance of CSF-1R signaling in the brain. PMID:28236968

Regulation of Embryonic and Postnatal Development by the CSF-1 Receptor.

PubMed

Chitu, Violeta; Stanley, E Richard

2017-01-01

Macrophages are found in all tissues and regulate tissue morphogenesis during development through trophic and scavenger functions. The colony stimulating factor-1 (CSF-1) receptor (CSF-1R) is the major regulator of tissue macrophage development and maintenance. In combination with receptor activator of nuclear factor κB (RANK), the CSF-1R also regulates the differentiation of the bone-resorbing osteoclast and controls bone remodeling during embryonic and early postnatal development. CSF-1R-regulated macrophages play trophic and remodeling roles in development. Outside the mononuclear phagocytic system, the CSF-1R directly regulates neuronal survival and differentiation, the development of intestinal Paneth cells and of preimplantation embryos, as well as trophoblast innate immune function. Consistent with the pleiotropic roles of the receptor during development, CSF-1R deficiency in most mouse strains causes embryonic or perinatal death and the surviving mice exhibit multiple developmental and functional deficits. The CSF-1R is activated by two dimeric glycoprotein ligands, CSF-1, and interleukin-34 (IL-34). Homozygous Csf1-null mutations phenocopy most of the deficits of Csf1r-null mice. In contrast, Il34-null mice have no gross phenotype, except for decreased numbers of Langerhans cells and microglia, indicating that CSF-1 plays the major developmental role. Homozygous inactivating mutations of the Csf1r or its ligands have not been reported in man. However, heterozygous inactivating mutations in the Csf1r lead to a dominantly inherited adult-onset progressive dementia, highlighting the importance of CSF-1R signaling in the brain. © 2017 Elsevier Inc. All rights reserved.

Distinct functions of Crumbs regulating slit diaphragms and endocytosis in Drosophila nephrocytes.

PubMed

Hochapfel, Florian; Denk, Lucia; Mendl, Gudrun; Schulze, Ulf; Maaßen, Christine; Zaytseva, Yulia; Pavenstädt, Hermann; Weide, Thomas; Rachel, Reinhard; Witzgall, Ralph; Krahn, Michael P

2017-12-01

Mammalian podocytes, the key determinants of the kidney's filtration barrier, differentiate from columnar epithelial cells and several key determinants of apical-basal polarity in the conventional epithelia have been shown to regulate podocyte morphogenesis and function. However, little is known about the role of Crumbs, a conserved polarity regulator in many epithelia, for slit-diaphragm formation and podocyte function. In this study, we used Drosophila nephrocytes as model system for mammalian podocytes and identified a conserved function of Crumbs proteins for cellular morphogenesis, nephrocyte diaphragm assembly/maintenance, and endocytosis. Nephrocyte-specific knock-down of Crumbs results in disturbed nephrocyte diaphragm assembly/maintenance and decreased endocytosis, which can be rescued by Drosophila Crumbs as well as human Crumbs2 and Crumbs3, which were both expressed in human podocytes. In contrast to the extracellular domain, which facilitates nephrocyte diaphragm assembly/maintenance, the intracellular FERM-interaction motif of Crumbs is essential for regulating endocytosis. Moreover, Moesin, which binds to the FERM-binding domain of Crumbs, is essential for efficient endocytosis. Thus, we describe here a new mechanism of nephrocyte development and function, which is likely to be conserved in mammalian podocytes.

Cdc42 regulates junctional actin but not cell polarization in the Caenorhabditis elegans epidermis

PubMed Central

Zilberman, Yuliya; Abrams, Joshua; Anderson, Dorian C.

2017-01-01

During morphogenesis, adherens junctions (AJs) remodel to allow changes in cell shape and position while preserving adhesion. Here, we examine the function of Rho guanosine triphosphatase CDC-42 in AJ formation and regulation during Caenorhabditis elegans embryo elongation, a process driven by asymmetric epidermal cell shape changes. cdc-42 mutant embryos arrest during elongation with epidermal ruptures. Unexpectedly, we find using time-lapse fluorescence imaging that cdc-42 is not required for epidermal cell polarization or junction assembly, but rather is needed for proper junctional actin regulation during elongation. We show that the RhoGAP PAC-1/ARHGAP21 inhibits CDC-42 activity at AJs, and loss of PAC-1 or the interacting linker protein PICC-1/CCDC85A-C blocks elongation in embryos with compromised AJ function. pac-1 embryos exhibit dynamic accumulations of junctional F-actin and an increase in AJ protein levels. Our findings identify a previously unrecognized molecular mechanism for inhibiting junctional CDC-42 to control actin organization and AJ protein levels during epithelial morphogenesis. PMID:28903999

Epithelial heparan sulfate regulates Sonic Hedgehog signaling in lung development.

PubMed

He, Hua; Huang, Meina; Sun, Shenfei; Wu, Yihui; Lin, Xinhua

2017-08-01

The tree-like structure of the mammalian lung is generated from branching morphogenesis, a reiterative process that is precisely regulated by numerous factors. How the cell surface and extra cellular matrix (ECM) molecules regulate this process is still poorly understood. Herein, we show that epithelial deletion of Heparan Sulfate (HS) synthetase Ext1 resulted in expanded branching tips and reduced branching number, associated with several mesenchymal developmental defects. We further demonstrate an expanded Fgf10 expression and increased FGF signaling activity in Ext1 mutant lungs, suggesting a cell non-autonomous mechanism. Consistent with this, we observed reduced levels of SHH signaling which is responsible for suppressing Fgf10 expression. Moreover, reactivating SHH signaling in mutant lungs rescued the tip dilation phenotype and attenuated FGF signaling. Importantly, the reduced SHH signaling activity did not appear to be caused by decreased Shh expression or protein stability; instead, biologically active form of SHH proteins were reduced in both the Ext1 mutant epithelium and surrounding wild type mesenchymal cells. Together, our study highlights the epithelial HS as a key player for dictating SHH signaling critical for lung morphogenesis.

Cell cycle progression is required for zebrafish somite morphogenesis but not segmentation clock function

PubMed Central

Zhang, Lixia; Kendrick, Christina; Jülich, Dörthe; Holley, Scott A.

2010-01-01

Summary Cell division, differentiation and morphogenesis are coordinated during embryonic development and frequently in disarray in pathologies such as cancer. Here, we present a zebrafish mutant that ceases mitosis at the beginning of gastrulation, but undergoes axis elongation and develops blood, muscle and a beating heart. We identify the mutation as being in early mitotic inhibitor 1 (emi1), a negative regulator of the Anaphase Promoting Complex, and utilize the mutant to examine the role of the cell cycle in somitogenesis. The mutant phenotype indicates that axis elongation during the segmentation period is substantially driven by cell migration. We find that the segmentation clock, which regulates somitogenesis, functions normally in the absence of cell cycle progression and observe that mitosis is a modest source of noise for the clock. Somite morphogenesis involves the epithelialization of the somite border cells around a core of mesenchyme. As in wild-type embryos, somite boundary cells are polarized along a Fibronectin matrix in emi1−/−. The mutants also display evidence of segment polarity. However, in the absence of a normal cell cycle, somites appear to hyper-epithelialize as the internal mesenchymal cells exit the core of the somite after initial boundary formation. Thus, cell cycle progression is not required during the segmentation period for segmentation clock function but is necessary for normal segmental arrangement of epithelial borders and internal mesenchymal cells. PMID:18480162

Influence of RNase E deficiency on the production of stx2-bearing phages and Shiga toxin in an RNase E-inducible strain of enterohaemorrhagic Escherichia coli (EHEC) O157:H7.

PubMed

Thuraisamy, Thujitha; Lodato, Patricia B

2018-05-01

In enterohaemorrhagic Escherichia coli (EHEC), stx1 or stx2 genes encode Shiga toxin (Stx1 or Stx2, respectively) and are carried by prophages. The production and release of both stx phages and toxin occur upon initiation of the phage lytic cycle. Phages can further disseminate stx genes by infecting naïve bacteria in the intestine. Here, the effect of RNase E deficiency on these two virulence traits was investigated. Cultures of the EHEC strains TEA028-rne containing low versus normal RNase E levels or the parental strain (TEA028) were treated with mitomycin C (MMC) to induce the phage lytic cycle. Phages and Stx2 titres were quantified by the double-agar assay and the receptor ELISA technique, respectively. RNase E deficiency in MMC-treated cells significantly reduced the yield of infectious stx2 phages. Delayed cell lysis and the appearance of encapsidated phage DNA copies suggest a slow onset of the lytic cycle. However, these observations do not entirely explain the decrease of phage yields. stx1 phages were not detected under normal or deficient RNase E levels. After an initial delay, high levels of toxin were finally produced in MMC-treated cultures. RNase E scarcity reduces stx2 phage production but not toxin. Normal concentrations of RNase E are likely required for correct phage morphogenesis. Our future work will address the mechanism of RNase E action on phage morphogenesis.

Patterns of muscular strain in the embryonic heart wall.

PubMed

Damon, Brooke J; Rémond, Mathieu C; Bigelow, Michael R; Trusk, Thomas C; Xie, Wenjie; Perucchio, Renato; Sedmera, David; Denslow, Stewart; Thompson, Robert P

2009-06-01

The hypothesis that inner layers of contracting muscular tubes undergo greater strain than concentric outer layers was tested by numerical modeling and by confocal microscopy of strain within the wall of the early chick heart. We modeled the looped heart as a thin muscular shell surrounding an inner layer of sponge-like trabeculae by two methods: calculation within a two-dimensional three-variable lumped model and simulated expansion of a three-dimensional, four-layer mesh of finite elements. Analysis of both models, and correlative microscopy of chamber dimensions, sarcomere spacing, and membrane leaks, indicate a gradient of strain decreasing across the wall from highest strain along inner layers. Prediction of wall thickening during expansion was confirmed by ultrasonography of beating hearts. Degree of stretch determined by radial position may thus contribute to observed patterns of regional myocardial conditioning and slowed proliferation, as well as to the morphogenesis of ventricular trabeculae and conduction fascicles. Developmental Dynamics 238:1535-1546, 2009. (c) 2009 Wiley-Liss, Inc.

Transcriptome analysis reveals the complexity of alternative splicing regulation in the fungus Verticillium dahliae.

PubMed

Jin, Lirong; Li, Guanglin; Yu, Dazhao; Huang, Wei; Cheng, Chao; Liao, Shengjie; Wu, Qijia; Zhang, Yi

2017-02-06

Alternative splicing (AS) regulation is extensive and shapes the functional complexity of higher organisms. However, the contribution of alternative splicing to fungal biology is not well studied. This study provides sequences of the transcriptomes of the plant wilt pathogen Verticillium dahliae, using two different strains and multiple methods for cDNA library preparations. We identified alternatively spliced mRNA isoforms in over a half of the multi-exonic fungal genes. Over one-thousand isoforms involve TopHat novel splice junction; multiple types of combinatory alternative splicing patterns were identified. We showed that one Verticillium gene could use four different 5' splice sites and two different 3' donor sites to produce up to five mature mRNAs, representing one of the most sophisticated alternative splicing model in eukaryotes other than animals. Hundreds of novel intron types involving a pair of new splice sites were identified in the V. dahliae genome. All the types of AS events were validated by using RT-PCR. Functional enrichment analysis showed that AS genes are involved in most known biological functions and enriched in ATP biosynthesis, sexual/asexual reproduction, morphogenesis, signal transduction etc., predicting that the AS regulation modulates mRNA isoform output and shapes the V. dahliae proteome plasticity of the pathogen in response to the environmental and developmental changes. These findings demonstrate the comprehensive alternative splicing mechanisms in a fungal plant pathogen, which argues the importance of this fungus in developing complicate genome regulation strategies in eukaryotes.

Regulation of BolA abundance mediates morphogenesis in Fremyella diplosiphon

DOE PAGES

Singh, Shailendra P.; Montgomery, Beronda L.

2015-11-05

Filamentous cyanobacterium Fremyella diplosiphon is known to alter its pigmentation and morphology during complementary chromatic acclimation (CCA) to efficiently harvest available radiant energy for photosynthesis. F. diplosiphon cells are rectangular and filaments are longer under green light (GL), whereas smaller, spherical cells and short filaments are prevalent under red light (RL). Light regulation of bolA morphogene expression is correlated with photoregulation of cellular morphology in F. diplosiphon. Here, we investigate a role for quantitative regulation of cellular BolA protein levels in morphology determination. Overexpression of bolA in WT was associated with induction of RL-characteristic spherical morphology even when cultures weremore » grown under GL. Overexpression of bolA in a ΔrcaE background, which lacks cyanobacteriochrome photosensor RcaE and accumulates lower levels of BolA than WT, partially reverted the cellular morphology of the strain to a WT-like state. Overexpression of BolA in WT and ΔrcaE backgrounds was associated with decreased cellular reactive oxygen species (ROS) levels and an increase in filament length under both GL and RL. Morphological defects and high ROS levels commonly observed in ΔrcaE could, thus, be in part due to low accumulation of BolA. Together, these findings support an emerging model for RcaE-dependent photoregulation of BolA in controlling the cellular morphology of F. diplosiphon during CCA.« less

A trehalose biosynthetic enzyme doubles as an osmotic stress sensor to regulate bacterial morphogenesis.

PubMed

Chen, Ximing; An, Lizhe; Fan, Xiaochuan; Ju, Furong; Zhang, Binglin; Sun, Haili; Xiao, Jianxi; Hu, Wei; Qu, Tao; Guan, Liping; Tang, Shukun; Chen, Tuo; Liu, Guangxiu; Dyson, Paul

2017-10-01

The dissacharide trehalose is an important intracellular osmoprotectant and the OtsA/B pathway is the principal pathway for trehalose biosynthesis in a wide range of bacterial species. Scaffolding proteins and other cytoskeletal elements play an essential role in morphogenetic processes in bacteria. Here we describe how OtsA, in addition to its role in trehalose biosynthesis, functions as an osmotic stress sensor to regulate cell morphology in Arthrobacter strain A3. In response to osmotic stress, this and other Arthrobacter species undergo a transition from bacillary to myceloid growth. An otsA null mutant exhibits constitutive myceloid growth. Osmotic stress leads to a depletion of trehalose-6-phosphate, the product of the OtsA enzyme, and experimental depletion of this metabolite also leads to constitutive myceloid growth independent of OtsA function. In vitro analyses indicate that OtsA can self-assemble into protein networks, promoted by trehalose-6-phosphate, a property that is not shared by the equivalent enzyme from E. coli, despite the latter's enzymatic activity when expressed in Arthrobacter. This, and the localization of the protein in non-stressed cells at the mid-cell and poles, indicates that OtsA from Arthrobacter likely functions as a cytoskeletal element regulating cell morphology. Recruiting a biosynthetic enzyme for this morphogenetic function represents an intriguing adaptation in bacteria that can survive in extreme environments.

Cellular and molecular mechanisms coordinating pancreas development.

PubMed

Bastidas-Ponce, Aimée; Scheibner, Katharina; Lickert, Heiko; Bakhti, Mostafa

2017-08-15

The pancreas is an endoderm-derived glandular organ that participates in the regulation of systemic glucose metabolism and food digestion through the function of its endocrine and exocrine compartments, respectively. While intensive research has explored the signaling pathways and transcriptional programs that govern pancreas development, much remains to be discovered regarding the cellular processes that orchestrate pancreas morphogenesis. Here, we discuss the developmental mechanisms and principles that are known to underlie pancreas development, from induction and lineage formation to morphogenesis and organogenesis. Elucidating such principles will help to identify novel candidate disease genes and unravel the pathogenesis of pancreas-related diseases, such as diabetes, pancreatitis and cancer. © 2017. Published by The Company of Biologists Ltd.

Cell death and morphogenesis during early mouse development: Are they interconnected?

PubMed Central

Bedzhov, Ivan; Zernicka-Goetz, Magdalena

2015-01-01

Shortly after implantation the embryonic lineage transforms from a coherent ball of cells into polarized cup shaped epithelium. Recently we elucidated a previously unknown apoptosis-independent morphogenic event that reorganizes the pluripotent lineage. Polarization cues from the surrounding basement membrane rearrange the epiblast into a polarized rosette-like structure, where subsequently a central lumen is established. Thus, we provided a new model revising the current concept of apoptosis-dependent epiblast morphogenesis. Cell death however has to be tightly regulated during embryogenesis to ensure developmental success. Here, we follow the stages of early mouse development and take a glimpse at the critical signaling and morphogenic events that determine cells destiny and reshape the embryonic lineage. PMID:25640415

Fungal Morphogenetic Pathways Are Required for the Hallmark Inflammatory Response during Candida albicans Vaginitis

PubMed Central

Palmer, Glen E.; Nash, Andrea K.; Lilly, Elizabeth A.; Fidel, Paul L.; Noverr, Mairi C.

2014-01-01

Vulvovaginal candidiasis, caused primarily by Candida albicans, presents significant health issues for women of childbearing age. As a polymorphic fungus, the ability of C. albicans to switch between yeast and hyphal morphologies is considered its central virulence attribute. Armed with new criteria for defining vaginitis immunopathology, the purpose of this study was to determine whether the yeast-to-hypha transition is required for the hallmark inflammatory responses previously characterized during murine vaginitis. Kinetic analyses of vaginal infection with C. albicans in C57BL/6 mice demonstrated that fungal burdens remained constant throughout the observation period, while polymorphonuclear leukocyte (PMN), S100A8, and interleukin-1β levels obtained from vaginal lavage fluid increased by day 3 onward. Lactate dehydrogenase activity was also positively correlated with increased effectors of innate immunity. Additionally, immunodepletion of neutrophils in infected mice confirmed a nonprotective role for PMNs during vaginitis. Determination of the importance of fungal morphogenesis during vaginitis was addressed with a two-pronged approach. Intravaginal inoculation of mice with C. albicans strains deleted for key transcriptional regulators (bcr1Δ/Δ, efg1Δ/Δ, cph1Δ/Δ, and efg1Δ/Δ cph1Δ/Δ) controlling the yeast-to-hypha switch revealed a crucial role for morphogenetic signaling through the Efg1 and, to a lesser extent, the Bcr1 pathways in contributing to vaginitis immunopathology. Furthermore, overexpression of transcription factors NRG1 and UME6, to maintain yeast and hyphal morphologies, respectively, confirmed the importance of morphogenesis in generating innate immune responses in vivo. These results highlight the yeast-to-hypha switch and the associated morphogenetic response as important virulence components for the immunopathogenesis of Candida vaginitis, with implications for transition from benign colonization to symptomatic infection. PMID:24478069

The F-BAR domains from srGAP1, srGAP2 and srGAP3 regulate membrane deformation differently

PubMed Central

Coutinho-Budd, Jaeda; Ghukasyan, Vladimir; Zylka, Mark J.; Polleux, Franck

2012-01-01

Summary Coordination of membrane deformation and cytoskeletal dynamics lies at the heart of many biological processes critical for cell polarity, motility and morphogenesis. We have recently shown that Slit-Robo GTPase-activating protein 2 (srGAP2) regulates neuronal morphogenesis through the ability of its F-BAR domain to regulate membrane deformation and induce filopodia formation. Here, we demonstrate that the F-BAR domains of two closely related family members, srGAP1 and srGAP3 [designated F-BAR(1) and F-BAR(3), respectively] display significantly different membrane deformation properties in non-neuronal COS7 cells and in cortical neurons. F-BAR(3) induces filopodia in both cell types, though less potently than F-BAR(2), whereas F-BAR(1) prevents filopodia formation in cortical neurons and reduces plasma membrane dynamics. These three F-BAR domains can heterodimerize, and they act synergistically towards filopodia induction in COS7 cells. As measured by fluorescence recovery after photobleaching, F-BAR(2) displays faster molecular dynamics than F-BAR(3) and F-BAR(1) at the plasma membrane, which correlates well with its increased potency to induce filopodia. We also show that the molecular dynamic properties of F-BAR(2) at the membrane are partially dependent on F-Actin. Interestingly, acute phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] depletion in cells does not interfere with plasma membrane localization of F-BAR(2), which is compatible with our result showing that F-BAR(2) binds to a broad range of negatively-charged phospholipids present at the plasma membrane, including phosphatidylserine (PtdSer). Overall, our results provide novel insights into the functional diversity of the membrane deformation properties of this subclass of F-BAR-domains required for cell morphogenesis. PMID:22467852

Regulation of root morphogenesis in arbuscular mycorrhizae: what role do fungal exudates, phosphate, sugars and hormones play in lateral root formation?

PubMed Central

Fusconi, Anna

2014-01-01

Background Arbuscular mycorrhizae (AMs) form a widespread root–fungus symbiosis that improves plant phosphate (Pi) acquisition and modifies the physiology and development of host plants. Increased branching is recognized as a general feature of AM roots, and has been interpreted as a means of increasing suitable sites for colonization. Fungal exudates, which are involved in the dialogue between AM fungi and their host during the pre-colonization phase, play a well-documented role in lateral root (LR) formation. In addition, the increased Pi content of AM plants, in relation to Pi-starved controls, as well as changes in the delivery of carbohydrates to the roots and modulation of phytohormone concentration, transport and sensitivity, are probably involved in increasing root system branching. Scope This review discusses the possible causes of increased branching in AM plants. The differential root responses to Pi, sugars and hormones of potential AM host species are also highlighted and discussed in comparison with those of the non-host Arabidopsis thaliana. Conclusions Fungal exudates are probably the main compounds regulating AM root morphogenesis during the first colonization steps, while a complex network of interactions governs root development in established AMs. Colonization and high Pi act synergistically to increase root branching, and sugar transport towards the arbusculated cells may contribute to LR formation. In addition, AM colonization and high Pi generally increase auxin and cytokinin and decrease ethylene and strigolactone levels. With the exception of cytokinins, which seem to regulate mainly the root:shoot biomass ratio, these hormones play a leading role in governing root morphogenesis, with strigolactones and ethylene blocking LR formation in the non-colonized, Pi-starved plants, and auxin inducing them in colonized plants, or in plants grown under high Pi conditions. PMID:24227446

Connecting Teratogen-Induced Congenital Heart Defects to Neural Crest Cells and Their Effect on Cardiac Function

PubMed Central

Karunamuni, Ganga H.; Ma, Pei; Gu, Shi; Rollins, Andrew M.; Jenkins, Michael W.; Watanabe, Michiko

2014-01-01

Neural crest cells play many key roles in embryonic development, as demonstrated by the abnormalities that result from their specific absence or dysfunction. Unfortunately, these key cells are particularly sensitive to abnormalities in various intrinsic and extrinsic factors, such as genetic deletions or ethanol-exposure that lead to morbidity and mortality for organisms. This review discusses the role identified for a segment of neural crest is in regulating the morphogenesis of the heart and associated great vessels. The paradox is that their derivatives constitute a small proportion of cells to the cardiovascular system. Findings supporting that these cells impact early cardiac function raises the interesting possibility that they indirectly control cardiovascular development at least partially through regulating function. Making connections between insults to the neural crest, cardiac function, and morphogenesis is more approachable with technological advances. Expanding our understanding of early functional consequences could be useful in improving diagnosis and testing therapies. PMID:25220155

The hypothalamic neuropeptide oxytocin is required for formation of the neurovascular interface of the pituitary.

PubMed

Gutnick, Amos; Blechman, Janna; Kaslin, Jan; Herwig, Lukas; Belting, Heinz-Georg; Affolter, Markus; Bonkowsky, Joshua L; Levkowitz, Gil

2011-10-18

The hypothalamo-neurohypophyseal system (HNS) is the neurovascular structure through which the hypothalamic neuropeptides oxytocin and arginine-vasopressin exit the brain into the bloodstream, where they go on to affect peripheral physiology. Here, we investigate the molecular cues that regulate the neurovascular contact between hypothalamic axons and neurohypophyseal capillaries of the zebrafish. We developed a transgenic system in which both hypothalamic axons and neurohypophyseal vasculature can be analyzed in vivo. We identified the cellular organization of the zebrafish HNS as well as the dynamic processes that contribute to formation of the HNS neurovascular interface. We show that formation of this interface is regulated during development by local release of oxytocin, which affects endothelial morphogenesis. This cell communication process is essential for the establishment of a tight axovasal interface between the neurons and blood vessels of the HNS. We present a unique example of axons affecting endothelial morphogenesis through secretion of a neuropeptide. Copyright © 2011 Elsevier Inc. All rights reserved.

WAVE2 is required for directed cell migration and cardiovascular development.

PubMed

Yamazaki, Daisuke; Suetsugu, Shiro; Miki, Hiroaki; Kataoka, Yuki; Nishikawa, Shin-Ichi; Fujiwara, Takashi; Yoshida, Nobuaki; Takenawa, Tadaomi

2003-07-24

WAVE2, a protein related to Wiskott-Aldrich syndrome protein, is crucial for Rac-induced membrane ruffling, which is important in cell motility. Cell movement is essential for morphogenesis, but it is unclear how cell movement is regulated or related to morphogenesis. Here we show the physiological functions of WAVE2 by disruption of the WAVE2 gene in mice. WAVE2 was expressed predominantly in vascular endothelial cells during embryogenesis. WAVE2-/- embryos showed haemorrhages and died at about embryonic day 10. Deficiency in WAVE2 had no significant effect on vasculogenesis, but it decreased sprouting and branching of endothelial cells from existing vessels during angiogenesis. In WAVE2-/- endothelial cells, cell polarity formed in response to vascular endothelial growth factor, but the formation of lamellipodia at leading edges and capillaries was severely impaired. These findings indicate that WAVE2-regulated actin reorganization might be required for proper cell movement and that a lack of functional WAVE2 impairs angiogenesis in vivo.

Inhibition of Candida albicans Biofilm Formation by the Synthetic Lactoferricin Derived Peptide hLF1-11

PubMed Central

Morici, Paola; Fais, Roberta; Rizzato, Cosmeri

2016-01-01

The aim of this study was to evaluate the in vitro activity of the synthetic peptide hLF1-11 against biofilm produced by clinical isolates of Candida albicans with different fluconazole susceptibility. The antibiofilm activity of the peptide hLF1-11 was assessed in terms of reduction of biofilm cellular density, metabolic activity and sessile cell viability. The extent of morphogenesis in hLF1-11 treated and untreated biofilms was also investigated microscopically. Transcription levels of genes related to cell adhesion, hyphal development and extracellular matrix production were analysed by qRT-PCR in hLF1-11 treated and untreated biofilms. Exogenous dibutyryl-cAMP (db-cAMP) was used to rescue morphogenesis in cells exposed to the peptide. The results revealed that hLF1-11 exhibited an inhibitory effect on biofilm formation by all C. albicans isolates tested in a dose-dependent manner, regardless of their fluconazole susceptibility. Visual inspection of treated or untreated biofilm cells with an inverted microscope revealed a significant reduction in hyphal formation by hLF1-11 treated cells, as early as 3 hours of incubation. Moreover, hLF1-11 showed a reduced activity on preadherent cells. hLF1-11 induced the down-regulation of biofilm and hyphal-associated genes, which were predominantly regulated via the Ras1-cAMP-Efg1 pathway. Indeed, exogenous db-cAMP restored morphogenesis in hLF1-11 treated cells. The hLF1-11 peptide significantly inhibited biofilm formation by C. albicans mainly at early stages, interfering with biofilm cellular density and metabolic activity, and affected morphogenesis through the Ras1-cAMP-Efg1 pathway. Our findings provide the first evidence that hLF1-11 could represent a potential candidate for the prevention of biofilm formation by C. albicans. PMID:27902776

Inhibition of Candida albicans Biofilm Formation by the Synthetic Lactoferricin Derived Peptide hLF1-11.

PubMed

Morici, Paola; Fais, Roberta; Rizzato, Cosmeri; Tavanti, Arianna; Lupetti, Antonella

2016-01-01

The aim of this study was to evaluate the in vitro activity of the synthetic peptide hLF1-11 against biofilm produced by clinical isolates of Candida albicans with different fluconazole susceptibility. The antibiofilm activity of the peptide hLF1-11 was assessed in terms of reduction of biofilm cellular density, metabolic activity and sessile cell viability. The extent of morphogenesis in hLF1-11 treated and untreated biofilms was also investigated microscopically. Transcription levels of genes related to cell adhesion, hyphal development and extracellular matrix production were analysed by qRT-PCR in hLF1-11 treated and untreated biofilms. Exogenous dibutyryl-cAMP (db-cAMP) was used to rescue morphogenesis in cells exposed to the peptide. The results revealed that hLF1-11 exhibited an inhibitory effect on biofilm formation by all C. albicans isolates tested in a dose-dependent manner, regardless of their fluconazole susceptibility. Visual inspection of treated or untreated biofilm cells with an inverted microscope revealed a significant reduction in hyphal formation by hLF1-11 treated cells, as early as 3 hours of incubation. Moreover, hLF1-11 showed a reduced activity on preadherent cells. hLF1-11 induced the down-regulation of biofilm and hyphal-associated genes, which were predominantly regulated via the Ras1-cAMP-Efg1 pathway. Indeed, exogenous db-cAMP restored morphogenesis in hLF1-11 treated cells. The hLF1-11 peptide significantly inhibited biofilm formation by C. albicans mainly at early stages, interfering with biofilm cellular density and metabolic activity, and affected morphogenesis through the Ras1-cAMP-Efg1 pathway. Our findings provide the first evidence that hLF1-11 could represent a potential candidate for the prevention of biofilm formation by C. albicans.

NFIX Regulates Neural Progenitor Cell Differentiation During Hippocampal Morphogenesis

PubMed Central

Heng, Yee Hsieh Evelyn; McLeay, Robert C.; Harvey, Tracey J.; Smith, Aaron G.; Barry, Guy; Cato, Kathleen; Plachez, Céline; Little, Erica; Mason, Sharon; Dixon, Chantelle; Gronostajski, Richard M.; Bailey, Timothy L.; Richards, Linda J.; Piper, Michael

2014-01-01

Neural progenitor cells have the ability to give rise to neurons and glia in the embryonic, postnatal and adult brain. During development, the program regulating whether these cells divide and self-renew or exit the cell cycle and differentiate is tightly controlled, and imbalances to the normal trajectory of this process can lead to severe functional consequences. However, our understanding of the molecular regulation of these fundamental events remains limited. Moreover, processes underpinning development of the postnatal neurogenic niches within the cortex remain poorly defined. Here, we demonstrate that Nuclear factor one X (NFIX) is expressed by neural progenitor cells within the embryonic hippocampus, and that progenitor cell differentiation is delayed within Nfix−/− mice. Moreover, we reveal that the morphology of the dentate gyrus in postnatal Nfix−/− mice is abnormal, with fewer subgranular zone neural progenitor cells being generated in the absence of this transcription factor. Mechanistically, we demonstrate that the progenitor cell maintenance factor Sry-related HMG box 9 (SOX9) is upregulated in the hippocampus of Nfix−/− mice and demonstrate that NFIX can repress Sox9 promoter-driven transcription. Collectively, our findings demonstrate that NFIX plays a central role in hippocampal morphogenesis, regulating the formation of neuronal and glial populations within this structure. PMID:23042739

Case Study: Organotypic human in vitro models of embryonic ...

EPA Pesticide Factsheets

Morphogenetic fusion of tissues is a common event in embryonic development and disruption of fusion is associated with birth defects of the eye, heart, neural tube, phallus, palate, and other organ systems. Embryonic tissue fusion requires precise regulation of cell-cell and cell-matrix interactions that drive proliferation, differentiation, and morphogenesis. Chemical low-dose exposures can disrupt morphogenesis across space and time by interfering with key embryonic fusion events. The Morphogenetic Fusion Task uses computer and in vitro models to elucidate consequences of developmental exposures. The Morphogenetic Fusion Task integrates multiple approaches to model responses to chemicals that leaad to birth defects, including integrative mining on ToxCast DB, ToxRefDB, and chemical structures, advanced computer agent-based models, and human cell-based cultures that model disruption of cellular and molecular behaviors including mechanisms predicted from integrative data mining and agent-based models. The purpose of the poster is to indicate progress on the CSS 17.02 Virtual Tissue Models Morphogenesis Task 1 products for the Board of Scientific Counselors meeting on Nov 16-17.

HGF-induced serine 897 phosphorylation of EphA2 regulates epithelial morphogenesis of MDCK cells in 3D culture.

PubMed

Harada, Kohei; Negishi, Manabu; Katoh, Hironori

2015-05-15

Expression of EphA2 is upregulated in various cancers that are derived from epithelial cells and correlates with the ability of a cancer cell to undergo migration and invasion. Here we have investigated the role of EphA2 in the epithelial morphogenesis of Madin-Darby canine kidney (MDCK) cells in three-dimensional culture. We show that EphA2 is phosphorylated on serine residue 897 through hepatocyte growth factor (HGF) stimulation using a phosphatidylinositol 3-kinase (PI3K)-Akt-dependent mechanism and that this phosphorylation is required for the formation of extensions, the first step of tubulogenesis, in MDCK cysts. By contrast, stimulation using the ligand ephrinA1 dephosphorylates EphA2 on serine residue 897 and suppresses the HGF-induced morphological change. Furthermore, activation of the small GTPase RhoG is involved in the HGF-induced formation of extensions downstream of EphA2. These observations suggest that a ligand-independent activity of EphA2 contributes to epithelial morphogenesis. © 2015. Published by The Company of Biologists Ltd.

New potential markers of in vitro tomato morphogenesis identified by mRNA differential display.

PubMed

Torelli, A; Soragni, E; Bolchi, A; Petrucco, S; Ottonello, S; Branca, C

1996-12-01

The identification of plant genes involved in early phases of in vitro morphogenesis can not only contribute to our understanding of the processes underlying growth regulator-controlled determination, but also provide novel markers for evaluating the outcome of in vitro regeneration experiments. To search for such genes and to monitor changes in gene expression accompanying in vitro regeneration, we have adapted the mRNA differential display technique to the comparative analysis of a model system of tomato cotyledons that can be driven selectively toward either shoot or callus formation by means of previously determined growth regulator supplementations. Hormone-independent transcriptional modulation (mainly down-regulation) has been found to be the most common event, indicating that a non-specific reprogramming of gene expression quantitatively predominates during the early phases of in vitro culture. However, cDNA fragments representative of genes that are either down-regulated or induced in a programme-specific manner could also be identified, and two of them (G35, G36) were further characterized. One of these cDNA fragments, G35, corresponds to an mRNA that is down-regulated much earlier in callus- (day 2) than in shoot-determined explants (day 6). The other, G36, identifies an mRNA that is transiently expressed in shoot-determined explants only, well before any macroscopic signs of differentiation become apparent, and thus exhibits typical features of a morphogenetic marker.

BMP signaling controls buckling forces to modulate looping morphogenesis of the gut.

PubMed

Nerurkar, Nandan L; Mahadevan, L; Tabin, Clifford J

2017-02-28

Looping of the initially straight embryonic gut tube is an essential aspect of intestinal morphogenesis, permitting proper placement of the lengthy small intestine within the confines of the body cavity. The formation of intestinal loops is highly stereotyped within a given species and results from differential-growth-driven mechanical buckling of the gut tube as it elongates against the constraint of a thin, elastic membranous tissue, the dorsal mesentery. Although the physics of this process has been studied, the underlying biology has not. Here, we show that BMP signaling plays a critical role in looping morphogenesis of the avian small intestine. We first exploited differences between chicken and zebra finch gut morphology to identify the BMP pathway as a promising candidate to regulate differential growth in the gut. Next, focusing on the developing chick small intestine, we determined that Bmp2 expressed in the dorsal mesentery establishes differential elongation rates between the gut tube and mesentery, thereby regulating the compressive forces that buckle the gut tube into loops. Consequently, the number and tightness of loops in the chick small intestine can be increased or decreased directly by modulation of BMP activity in the small intestine. In addition to providing insight into the molecular mechanisms underlying intestinal development, our findings provide an example of how biochemical signals act on tissue-level mechanics to drive organogenesis, and suggest a possible mechanism by which they can be modulated to achieve distinct morphologies through evolution.

BMP signaling controls buckling forces to modulate looping morphogenesis of the gut

PubMed Central

Nerurkar, Nandan L.; Mahadevan, L.; Tabin, Clifford J.

2017-01-01

Looping of the initially straight embryonic gut tube is an essential aspect of intestinal morphogenesis, permitting proper placement of the lengthy small intestine within the confines of the body cavity. The formation of intestinal loops is highly stereotyped within a given species and results from differential-growth–driven mechanical buckling of the gut tube as it elongates against the constraint of a thin, elastic membranous tissue, the dorsal mesentery. Although the physics of this process has been studied, the underlying biology has not. Here, we show that BMP signaling plays a critical role in looping morphogenesis of the avian small intestine. We first exploited differences between chicken and zebra finch gut morphology to identify the BMP pathway as a promising candidate to regulate differential growth in the gut. Next, focusing on the developing chick small intestine, we determined that Bmp2 expressed in the dorsal mesentery establishes differential elongation rates between the gut tube and mesentery, thereby regulating the compressive forces that buckle the gut tube into loops. Consequently, the number and tightness of loops in the chick small intestine can be increased or decreased directly by modulation of BMP activity in the small intestine. In addition to providing insight into the molecular mechanisms underlying intestinal development, our findings provide an example of how biochemical signals act on tissue-level mechanics to drive organogenesis, and suggest a possible mechanism by which they can be modulated to achieve distinct morphologies through evolution. PMID:28193855

Analysis of developmental gene conservation in the Actinomycetales using DNA/DNA microarray comparisons.

PubMed

Kirby, Ralph; Herron, Paul; Hoskisson, Paul

2011-02-01

Based on available genome sequences, Actinomycetales show significant gene synteny across a wide range of species and genera. In addition, many genera show varying degrees of complex morphological development. Using the presence of gene synteny as a basis, it is clear that an analysis of gene conservation across the Streptomyces and various other Actinomycetales will provide information on both the importance of genes and gene clusters and the evolution of morphogenesis in these bacteria. Genome sequencing, although becoming cheaper, is still relatively expensive for comparing large numbers of strains. Thus, a heterologous DNA/DNA microarray hybridization dataset based on a Streptomyces coelicolor microarray allows a cheaper and greater depth of analysis of gene conservation. This study, using both bioinformatical and microarray approaches, was able to classify genes previously identified as involved in morphogenesis in Streptomyces into various subgroups in terms of conservation across species and genera. This will allow the targeting of genes for further study based on their importance at the species level and at higher evolutionary levels.

Using cell deformation and motion to predict forces and collective behavior in morphogenesis.

PubMed

Merkel, Matthias; Manning, M Lisa

2017-07-01

In multi-cellular organisms, morphogenesis translates processes at the cellular scale into tissue deformation at the scale of organs and organisms. To understand how biochemical signaling regulates tissue form and function, we must understand the mechanical forces that shape cells and tissues. Recent progress in developing mechanical models for tissues has led to quantitative predictions for how cell shape changes and polarized cell motility generate forces and collective behavior on the tissue scale. In particular, much insight has been gained by thinking about biological tissues as physical materials composed of cells. Here we review these advances and discuss how they might help shape future experiments in developmental biology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Notochord vacuoles are lysosome-related organelles that function in axis and spine morphogenesis.

PubMed

Ellis, Kathryn; Bagwell, Jennifer; Bagnat, Michel

2013-03-04

The notochord plays critical structural and signaling roles during vertebrate development. At the center of the vertebrate notochord is a large fluid-filled organelle, the notochord vacuole. Although these highly conserved intracellular structures have been described for decades, little is known about the molecular mechanisms involved in their biogenesis and maintenance. Here we show that zebrafish notochord vacuoles are specialized lysosome-related organelles whose formation and maintenance requires late endosomal trafficking regulated by the vacuole-specific Rab32a and H(+)-ATPase-dependent acidification. We establish that notochord vacuoles are required for body axis elongation during embryonic development and identify a novel role in spine morphogenesis. Thus, the vertebrate notochord plays important structural roles beyond early development.

Notochord vacuoles are lysosome-related organelles that function in axis and spine morphogenesis

PubMed Central

Ellis, Kathryn; Bagwell, Jennifer

2013-01-01

The notochord plays critical structural and signaling roles during vertebrate development. At the center of the vertebrate notochord is a large fluid-filled organelle, the notochord vacuole. Although these highly conserved intracellular structures have been described for decades, little is known about the molecular mechanisms involved in their biogenesis and maintenance. Here we show that zebrafish notochord vacuoles are specialized lysosome-related organelles whose formation and maintenance requires late endosomal trafficking regulated by the vacuole-specific Rab32a and H+-ATPase–dependent acidification. We establish that notochord vacuoles are required for body axis elongation during embryonic development and identify a novel role in spine morphogenesis. Thus, the vertebrate notochord plays important structural roles beyond early development. PMID:23460678

Cell death and morphogenesis during early mouse development: are they interconnected?

PubMed

Bedzhov, Ivan; Zernicka-Goetz, Magdalena

2015-04-01

Shortly after implantation the embryonic lineage transforms from a coherent ball of cells into polarized cup shaped epithelium. Recently we elucidated a previously unknown apoptosis-independent morphogenic event that reorganizes the pluripotent lineage. Polarization cues from the surrounding basement membrane rearrange the epiblast into a polarized rosette-like structure, where subsequently a central lumen is established. Thus, we provided a new model revising the current concept of apoptosis-dependent epiblast morphogenesis. Cell death however has to be tightly regulated during embryogenesis to ensure developmental success. Here, we follow the stages of early mouse development and take a glimpse at the critical signaling and morphogenic events that determine cells destiny and reshape the embryonic lineage. © 2015 The Authors. Bioessays published by WILEY Periodicals, Inc.

Genome Sequence of African Swine Fever Virus BA71, the Virulent Parental Strain of the Nonpathogenic and Tissue-Culture Adapted BA71V.

PubMed

Rodríguez, Javier M; Moreno, Leticia Tais; Alejo, Alí; Lacasta, Anna; Rodríguez, Fernando; Salas, María L

2015-01-01

The strain BA71V has played a key role in African swine fever virus (ASFV) research. It was the first genome sequenced, and remains the only genome completely determined. A large part of the studies on the function of ASFV genes, viral transcription, replication, DNA repair and morphogenesis, has been performed using this model. This avirulent strain was obtained by adaptation to grow in Vero cells of the highly virulent BA71 strain. We report here the analysis of the genome sequence of BA71 in comparison with that of BA71V. They possess the smallest genomes for a virulent or an attenuated ASFV, and are essentially identical except for a relatively small number of changes. We discuss the possible contribution of these changes to virulence. Analysis of the BA71 sequence allowed us to identify new similarities among ASFV proteins, and with database proteins including two ASFV proteins that could function as a two-component signaling network.

Microenvironments and Signaling Pathways Regulating Early Dissemination, Dormancy, and Metastasis

DTIC Science & Technology

2016-09-01

regulators of branching morphogenesis during mammary gland development 17,18, arguing that normal mammary epithelial cells cooperate with these innate ...CD45+CD11b+F4/80+ cells lacking lymphoid and granulocytic markers (Supplementary Fig.3B). viSNE plots 30 of myelo- monocytic cells (Fig.5A) showed that...cancer cells and how the microenvironment in these primary sites named P-TMEM (Primary Tumor Microenvironment of Metastases) contribute to early

Combination of Hypomorphic Mutations of the Drosophila Homologues of Aryl Hydrocarbon Receptor and Nucleosome Assembly Protein Family Genes Disrupts Morphogenesis, Memory and Detoxification

PubMed Central

Cherezov, Roman O.; Vorontsova, Julia E.; Slezinger, Mikhail S.; Zatsepina, Olga G.; Simonova, Olga B.; Enikolopov, Grigori N.; Savvateeva-Popova, Elena V.

2014-01-01

Aryl hydrocarbon receptor is essential for biological responses to endogenous and exogenous toxins in mammals. Its Drosophila homolog spineless plays an important role in fly morphogenesis. We have previously shown that during morphogenesis spineless genetically interacts with CG5017 gene, which encodes a nucleosome assembly factor and may affect cognitive function of the fly. We now demonstrate synergistic interactions of spineless and CG5017 in pathways controlling oxidative stress response and long-term memory formation in Drosophila melanogaster. Oxidative stress was induced by low doses of X-ray irradiation of flies carrying hypomorphic mutation of spineless, mutation of CG5017, and their combination. To determine the sensitivity of these mutants to pharmacological modifiers of the irradiation effect, we irradiated flies growing on standard medium supplemented by radiosensitizer furazidin and radioprotector serotonin. The effects of irradiation were investigated by analyzing leg and antenna morphological structures and by using real-time PCR to measure mRNA expression levels for spineless, Cyp6g1 and Gst-theta genes. We also examined long-term memory in these mutants using conditioned courtship suppression paradigm. Our results show that the interaction of spineless and CG5017 is important for regulation of morphogenesis, long-term memory formation, and detoxification during oxidative stress. Since spineless and CG5017 are evolutionary conserved, these results must be considered when evaluating the risk of combining similar mutations in other organisms, including humans. PMID:24736732

Combination of hypomorphic mutations of the Drosophila homologues of aryl hydrocarbon receptor and nucleosome assembly protein family genes disrupts morphogenesis, memory and detoxification.

PubMed

Kuzin, Boris A; Nikitina, Ekaterina A; Cherezov, Roman O; Vorontsova, Julia E; Slezinger, Mikhail S; Zatsepina, Olga G; Simonova, Olga B; Enikolopov, Grigori N; Savvateeva-Popova, Elena V

2014-01-01

Aryl hydrocarbon receptor is essential for biological responses to endogenous and exogenous toxins in mammals. Its Drosophila homolog spineless plays an important role in fly morphogenesis. We have previously shown that during morphogenesis spineless genetically interacts with CG5017 gene, which encodes a nucleosome assembly factor and may affect cognitive function of the fly. We now demonstrate synergistic interactions of spineless and CG5017 in pathways controlling oxidative stress response and long-term memory formation in Drosophila melanogaster. Oxidative stress was induced by low doses of X-ray irradiation of flies carrying hypomorphic mutation of spineless, mutation of CG5017, and their combination. To determine the sensitivity of these mutants to pharmacological modifiers of the irradiation effect, we irradiated flies growing on standard medium supplemented by radiosensitizer furazidin and radioprotector serotonin. The effects of irradiation were investigated by analyzing leg and antenna morphological structures and by using real-time PCR to measure mRNA expression levels for spineless, Cyp6g1 and Gst-theta genes. We also examined long-term memory in these mutants using conditioned courtship suppression paradigm. Our results show that the interaction of spineless and CG5017 is important for regulation of morphogenesis, long-term memory formation, and detoxification during oxidative stress. Since spineless and CG5017 are evolutionary conserved, these results must be considered when evaluating the risk of combining similar mutations in other organisms, including humans.

Signaling through protein kinases and transcriptional regulators in Candida albicans.

PubMed

Dhillon, Navneet K; Sharma, Sadhna; Khuller, G K

2003-01-01

The human fungal pathogen Candida albicans switches from a budding yeast form to a polarized hyphal form in response to various external signals. This morphogenetic switching has been implicated in the development of pathogenicity. Several signaling pathways that regulate morphogenesis have been identified, including various transcription factors that either activate or repress hypha-specific genes. Two well-characterized pathways include the MAP kinase cascade and cAMP-dependent protein kinase pathway that regulate the transcription factors Cph1p and Efg1p, respectively. cAMP also appears to interplay with other second messengers: Ca2+, inositol tri-phosphates in regulating yeast-hyphal transition. Other, less-characterized pathways include two component histidine kinases, cyclin-dependent kinase pathway, and condition specific pathways such as pH and embedded growth conditions. Nrg1 and Rfg1 function as transcriptional repressors of hyphal genes via recruitment of Tup1 co-repressor complex. Different upstream signals converge into a common downstream output during hyphal switch. The levels of expression of several genes have been shown to be associated with hyphal morphogenesis rather than with a specific hypha-inducing condition. Hyphal development is also linked to the expression of a range of other virulence factors. This review explains the relative contribution of multiple pathways that could be used by Candida albican cells to sense subtle differences in the growth conditions of its native host environment.

Post-transcriptional regulation of myotube elongation and myogenesis by Hoi Polloi

PubMed Central

Johnson, Aaron N.; Mokalled, Mayssa H.; Valera, Juliana M.; Poss, Kenneth D.; Olson, Eric N.

2013-01-01

Striated muscle development requires the coordinated expression of genes involved in sarcomere formation and contractility, as well as genes that determine muscle morphology. However, relatively little is known about the molecular mechanisms that control the early stages of muscle morphogenesis. To explore this facet of myogenesis, we performed a genetic screen for regulators of somatic muscle morphology in Drosophila, and identified the putative RNA-binding protein (RBP) Hoi Polloi (Hoip). Hoip is expressed in striated muscle precursors within the muscle lineage and controls two genetically separable events: myotube elongation and sarcomeric protein expression. Myotubes fail to elongate in hoip mutant embryos, even though the known regulators of somatic muscle elongation, target recognition and muscle attachment are expressed normally. In addition, a majority of sarcomeric proteins, including Myosin Heavy Chain (MHC) and Tropomyosin, require Hoip for their expression. A transgenic MHC construct that contains the endogenous MHC promoter and a spliced open reading frame rescues MHC protein expression in hoip embryos, demonstrating the involvement of Hoip in pre-mRNA splicing, but not in transcription, of muscle structural genes. In addition, the human Hoip ortholog NHP2L1 rescues muscle defects in hoip embryos, and knockdown of endogenous nhp2l1 in zebrafish disrupts skeletal muscle development. We conclude that Hoip is a conserved, post-transcriptional regulator of muscle morphogenesis and structural gene expression. PMID:23942517

Abelson Interactor 1 (Abi1) and Its Interaction with Wiskott-Aldrich Syndrome Protein (Wasp) Are Critical for Proper Eye Formation in Xenopus Embryos*

PubMed Central

Singh, Arvinder; Winterbottom, Emily F.; Ji, Yon Ju; Hwang, Yoo-Seok; Daar, Ira O.

2013-01-01

Abl interactor 1 (Abi1) is a scaffold protein that plays a central role in the regulation of actin cytoskeleton dynamics as a constituent of several key protein complexes, and homozygous loss of this protein leads to embryonic lethality in mice. Because this scaffold protein has been shown in cultured cells to be a critical component of pathways controlling cell migration and actin regulation at cell-cell contacts, we were interested to investigate the in vivo role of Abi1 in morphogenesis during the development of Xenopus embryos. Using morpholino-mediated translation inhibition, we demonstrate that knockdown of Abi1 in the whole embryo, or specifically in eye field progenitor cells, leads to disruption of eye morphogenesis. Moreover, signaling through the Src homology 3 domain of Abi1 is critical for proper movement of retinal progenitor cells into the eye field and their appropriate differentiation, and this process is dependent upon an interaction with the nucleation-promoting factor Wasp (Wiskott-Aldrich syndrome protein). Collectively, our data demonstrate that the Abi1 scaffold protein is an essential regulator of cell movement processes required for normal eye development in Xenopus embryos and specifically requires an Src homology 3 domain-dependent interaction with Wasp to regulate this complex morphogenetic process. PMID:23558677

Deciphering the Genetic Programme Triggering Timely and Spatially-Regulated Chitin Deposition

PubMed Central

Rotstein, Bárbara; Casali, Andreu; Llimargas, Marta

2015-01-01

Organ and tissue formation requires a finely tuned temporal and spatial regulation of differentiation programmes. This is necessary to balance sufficient plasticity to undergo morphogenesis with the acquisition of the mature traits needed for physiological activity. Here we addressed this issue by analysing the deposition of the chitinous extracellular matrix of Drosophila, an essential element of the cuticle (skin) and respiratory system (tracheae) in this insect. Chitin deposition requires the activity of the chitin synthase Krotzkopf verkehrt (Kkv). Our data demonstrate that this process equally requires the activity of two other genes, namely expansion (exp) and rebuf (reb). We found that Exp and Reb have interchangeable functions, and in their absence no chitin is produced, in spite of the presence of Kkv. Conversely, when Kkv and Exp/Reb are co-expressed in the ectoderm, they promote chitin deposition, even in tissues normally devoid of this polysaccharide. Therefore, our results indicate that both functions are not only required but also sufficient to trigger chitin accumulation. We show that this mechanism is highly regulated in time and space, ensuring chitin accumulation in the correct tissues and developmental stages. Accordingly, we observed that unregulated chitin deposition disturbs morphogenesis, thus highlighting the need for tight regulation of this process. In summary, here we identify the genetic programme that triggers the timely and spatially regulated deposition of chitin and thus provide new insights into the extracellular matrix maturation required for physiological activity. PMID:25617778

Mammalian aPKC/Par polarity complex mediated regulation of epithelial division orientation and cell fate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vorhagen, Susanne; Niessen, Carien M., E-mail: carien.niessen@uni-koeln.de

2014-11-01

Oriented cell division is a key regulator of tissue architecture and crucial for morphogenesis and homeostasis. Balanced regulation of proliferation and differentiation is an essential property of tissues not only to drive morphogenesis but also to maintain and restore homeostasis. In many tissues orientation of cell division is coupled to the regulation of differentiation producing daughters with similar (symmetric cell division, SCD) or differential fate (asymmetric cell division, ACD). This allows the organism to generate cell lineage diversity from a small pool of stem and progenitor cells. Division orientation and/or the ratio of ACD/SCD need to be tightly controlled. Lossmore » of orientation or an altered ratio can promote overgrowth, alter tissue architecture and induce aberrant differentiation, and have been linked to morphogenetic diseases, cancer and aging. A key requirement for oriented division is the presence of a polarity axis, which can be established through cell intrinsic and/or extrinsic signals. Polarity proteins translate such internal and external cues to drive polarization. In this review we will focus on the role of the polarity complex aPKC/Par3/Par6 in the regulation of division orientation and cell fate in different mammalian epithelia. We will compare the conserved function of this complex in mitotic spindle orientation and distribution of cell fate determinants and highlight common and differential mechanisms in which this complex is used by tissues to adapt division orientation and cell fate to the specific properties of the epithelium.« less

The small phytoplasma virulence effector SAP11 contains distinct domains required for nuclear targeting and CIN-TCP binding and destabilization.

PubMed

Sugio, Akiko; MacLean, Allyson M; Hogenhout, Saskia A

2014-05-01

Phytoplasmas are insect-transmitted bacterial phytopathogens that secrete virulence effectors and induce changes in the architecture and defense response of their plant hosts. We previously demonstrated that the small (± 10 kDa) virulence effector SAP11 of Aster Yellows phytoplasma strain Witches' Broom (AY-WB) binds and destabilizes Arabidopsis CIN (CINCINNATA) TCP (TEOSINTE-BRANCHED, CYCLOIDEA, PROLIFERATION FACTOR 1 AND 2) transcription factors, resulting in dramatic changes in leaf morphogenesis and increased susceptibility to phytoplasma insect vectors. SAP11 contains a bipartite nuclear localization signal (NLS) that targets this effector to plant cell nuclei. To further understand how SAP11 functions, we assessed the involvement of SAP11 regions in TCP binding and destabilization using a series of mutants. SAP11 mutants lacking the entire N-terminal domain, including the NLS, interacted with TCPs but did not destabilize them. SAP11 mutants lacking the C-terminal domain were impaired in both binding and destabilization of TCPs. These SAP11 mutants did not alter leaf morphogenesis. A SAP11 mutant that did not accumulate in plant nuclei (SAP11ΔNLS-NES) was able to bind and destabilize TCP transcription factors, but instigated weaker changes in leaf morphogenesis than wild-type SAP11. Overall the results suggest that phytoplasma effector SAP11 has a modular organization in which at least three domains are required for efficient CIN-TCP destabilization in plants. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Turtle Functions Downstream of Cut in Differentially Regulating Class Specific Dendrite Morphogenesis in Drosophila

PubMed Central

Sulkowski, Mikolaj J.; Iyer, Srividya Chandramouli; Kurosawa, Mathieu S.; Iyer, Eswar Prasad R.; Cox, Daniel N.

2011-01-01

Background Dendritic morphology largely determines patterns of synaptic connectivity and electrochemical properties of a neuron. Neurons display a myriad diversity of dendritic geometries which serve as a basis for functional classification. Several types of molecules have recently been identified which regulate dendrite morphology by acting at the levels of transcriptional regulation, direct interactions with the cytoskeleton and organelles, and cell surface interactions. Although there has been substantial progress in understanding the molecular mechanisms of dendrite morphogenesis, the specification of class-specific dendritic arbors remains largely unexplained. Furthermore, the presence of numerous regulators suggests that they must work in concert. However, presently, few genetic pathways regulating dendrite development have been defined. Methodology/Principal Findings The Drosophila gene turtle belongs to an evolutionarily conserved class of immunoglobulin superfamily members found in the nervous systems of diverse organisms. We demonstrate that Turtle is differentially expressed in Drosophila da neurons. Moreover, MARCM analyses reveal Turtle acts cell autonomously to exert class specific effects on dendritic growth and/or branching in da neuron subclasses. Using transgenic overexpression of different Turtle isoforms, we find context-dependent, isoform-specific effects on mediating dendritic branching in class II, III and IV da neurons. Finally, we demonstrate via chromatin immunoprecipitation, qPCR, and immunohistochemistry analyses that Turtle expression is positively regulated by the Cut homeodomain transcription factor and via genetic interaction studies that Turtle is downstream effector of Cut-mediated regulation of da neuron dendrite morphology. Conclusions/Significance Our findings reveal that Turtle proteins differentially regulate the acquisition of class-specific dendrite morphologies. In addition, we have established a transcriptional regulatory interaction between Cut and Turtle, representing a novel pathway for mediating class specific dendrite development. PMID:21811639

The regulation of tooth morphogenesis is associated with epithelial cell proliferation and the expression of Sonic hedgehog through epithelial-mesenchymal interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ishida, Kentaro; Murofushi, Mayumi; Nakao, Kazuhisa

2011-02-18

Research highlights: {yields} Bioengineered teeth regulated the contact area of epithelium and mesenchyme. {yields} The crown width is regulated by the contact area of the epithelium and mesenchyme. {yields} This regulation is associated with cell proliferation and Sonic hedgehog expression. {yields} The cusp number is correlated with the crown width of the bioengineered tooth. {yields} Cell proliferation and Shh expression areas regulate the tooth morphogenesis. -- Abstract: Ectodermal organs, such as the tooth, salivary gland, hair, and mammary gland, develop through reciprocal epithelial-mesenchymal interactions. Tooth morphologies are defined by the crown width and tooth length (macro-morphologies), and by the numbermore » and locations of the cusp and roots (micro-morphologies). In our current study, we report that the crown width of a bioengineered molar tooth, which was reconstructed using dissociated epithelial and mesenchymal cells via an organ germ method, can be regulated by the contact area between epithelial and mesenchymal cell layers. We further show that this is associated with cell proliferation and Sonic hedgehog (Shh) expression in the inner enamel epithelium after the germ stage has formed a secondary enamel knot. We also demonstrate that the cusp number is significantly correlated with the crown width of the bioengineered tooth. These findings suggest that the tooth micro-morphology, i.e. the cusp formation, is regulated after the tooth width, or macro-morphology, is determined. These findings also suggest that the spatiotemporal patterning of cell proliferation and the Shh expression areas in the epithelium regulate the crown width and cusp formation of the developing tooth.« less

Stage-specific differential gene expression profiling and functional network analysis during morphogenesis of diphyodont dentition in miniature pigs, Sus Scrofa

PubMed Central

2014-01-01

Background Our current knowledge of tooth development derives mainly from studies in mice, which have only one set of non-replaced teeth, compared with the diphyodont dentition in humans. The miniature pig is also diphyodont, making it a valuable alternative model for understanding human tooth development and replacement. However, little is known about gene expression and function during swine odontogenesis. The goal of this study is to undertake the survey of differential gene expression profiling and functional network analysis during morphogenesis of diphyodont dentition in miniature pigs. The identification of genes related to diphyodont development should lead to a better understanding of morphogenetic patterns and the mechanisms of diphyodont replacement in large animal models and humans. Results The temporal gene expression profiles during early diphyodont development in miniature pigs were detected with the Affymetrix Porcine GeneChip. The gene expression data were further evaluated by ANOVA as well as pathway and STC analyses. A total of 2,053 genes were detected with differential expression. Several signal pathways and 151 genes were then identified through the construction of pathway and signal networks. Conclusions The gene expression profiles indicated that spatio-temporal down-regulation patterns of gene expression were predominant; while, both dynamic activation and inhibition of pathways occurred during the morphogenesis of diphyodont dentition. Our study offers a mechanistic framework for understanding dynamic gene regulation of early diphyodont development and provides a molecular basis for studying teeth development, replacement, and regeneration in miniature pigs. PMID:24498892

Mesenchymal-epithelial interactions during hair follicle morphogenesis and cycling

PubMed Central

Sennett, Rachel; Rendl, Michael

2012-01-01

Embryonic hair follicle induction and formation are regulated by mesenchymal-epithelial interactions between specialized dermal cells and epidermal stem cells that switch to a hair fate. Similarly, during postnatal hair growth, communication between mesenchymal dermal papilla cells and surrounding epithelial matrix cells coordinates hair shaft production. Adult hair follicle regeneration in the hair cycle again is thought to be controlled by activating signals originating from the mesenchymal compartment and acting on hair follicle stem cells. Although many signaling pathways are implicated in hair follicle formation and growth, the precise nature, timing, and intersection of these inductive and regulatory signals remains elusive. The goal of this review is to summarize our current understanding and to discuss recent new insights into mesenchymal-epithelial interactions during hair follicle morphogenesis and cycling. PMID:22960356

Molecular mechanisms controlling pavement cell shape in Arabidopsis leaves.

PubMed

Qian, Pingping; Hou, Suiwen; Guo, Guangqin

2009-08-01

Pavement cells have an interlocking jigsaw puzzle-shaped leaf surface pattern. Twenty-three genes involved in the pavement cell morphogenesis were discovered until now. The mutations of these genes through various means lead to pavement cell shape defects, such as loss or lack of interdigitation, the reduction of lobing, gaps between lobe and neck regions in pavement cells, and distorted trichomes. These phenotypes are affected by the organization of microtubules and microfilaments. Microtubule bands are considered corresponding with the neck regions of the cell, while lobe formation depends on patches of microfilaments. The pathway of Rho of plant (ROP) GTPase signaling cascades regulates overall activity of the cytoskeleton in pavement cells. Some other proteins, in addition to the ROPs, SCAR/WAVE, and ARP2/3 complexes, are also involved in the pavement cell morphogenesis.

The role of integrin α8β1 in fetal lung morphogenesis and injury

PubMed Central

Benjamin, John T.; Gaston, David C.; Halloran, Brian A.; Schnapp, Lynn M.; Zent, Roy; Prince, Lawrence S.

2009-01-01

Prenatal inflammation prevents normal lung morphogenesis and leads to bronchopulmonary dysplasia (BPD), a common complication of preterm birth. We previously demonstrated in a bacterial endotoxin mouse model of BPD that disrupting fibronectin localization in the fetal lung mesenchyme causes arrested saccular airway branching. In this study we show that expression of the fibronectin receptor, integrin α8β1, is decreased in the lung mesenchyme in the same inflammation model suggesting it is required for normal lung development. We verified a role for integrin α8β1 in lung development using integrin α8-null mice, which develop fusion of the medial and caudal lobes as well as abnormalities in airway division. We further show in vivo and vitro that α8-null fetal lung mesenchymal cells fail to form stable adhesions and have increased migration. Thus we propose that integrin α8β1 plays a critical role in lung morphogenesis by regulating mesenchymal cell adhesion and migration. Furthermore, our data suggests that disruption of the interactions between extracellular matrix and integrin α8β1 may contribute to the pathogenesis of BPD. PMID:19769957

A model for neurite growth and neuronal morphogenesis.

PubMed

Li, G H; Qin, C D

1996-02-01

A model is presented for tensile regulation of neuritic growth. It is proposed that the neurite tension can be determined by Hooke's law and determines the growth rate of neurites. The growth of a neurite is defined as the change in its unstretched length. Neuritic growth rate is assumed to increase in proportion to tension magnitude over a certain threshold [Dennerll et al., J. Cell Biol. 107: 665-674 (1988)]. The movement of branch nodes also contributes to the neuronal morphogenesis. It is supposed that the rate of a branch-node displacement is in proportion to the resultant neuritic tension exerted on this node. To deal with the growth-cone movement, it is further supposed that the environment exerts a traction force on the growth cone and the rate of growth-cone displacement is determined by the vector sum of the neuritic tension and the traction force. A group of differential equations are used to describe the model. The key point of the model is that the traction force and the neuritic tension are in opposition to generate a temporal contrast-enhancing mechanism. Results of a simulation study suggest that the model can explain some phenomena related to neuronal morphogenesis.

The phosphoproteome of Aspergillus nidulans reveals functional association with cellular processes involved in morphology and secretion.

PubMed

Ramsubramaniam, Nikhil; Harris, Steven D; Marten, Mark R

2014-11-01

We describe the first phosphoproteome of the model filamentous fungus Aspergillus nidulans. Phosphopeptides were enriched using titanium dioxide, separated using a convenient ultra-long reverse phase gradient, and identified using a "high-high" strategy (high mass accuracy on the parent and fragment ions) with higher-energy collisional dissociation. Using this approach 1801 phosphosites, from 1637 unique phosphopeptides, were identified. Functional classification revealed phosphoproteins were overrepresented under GO categories related to fungal morphogenesis: "sites of polar growth," "vesicle mediated transport," and "cytoskeleton organization." In these same GO categories, kinase-substrate analysis of phosphoproteins revealed the majority were target substrates of CDK and CK2 kinase families, indicating these kinase families play a prominent role in fungal morphogenesis. Kinase-substrate analysis also identified 57 substrates for kinases known to regulate secretion of hydrolytic enzymes (e.g. PkaA, SchA, and An-Snf1). Altogether this data will serve as a benchmark that can be used to elucidate regulatory networks functionally associated with fungal morphogenesis and secretion. All MS data have been deposited in the ProteomeXchange with identifier PXD000715 (http://proteomecentral.proteomexchange.org/dataset/PXD000715). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cellular Basis of Mechanotransduction

NASA Technical Reports Server (NTRS)

Ingber, Donald E.

1996-01-01

Physical forces, such as those due to gravity are fundamental regulators of tissue development. To influence morphogenesis, mechanical forces must alter growth and function. Yet little is known about how cells convert mechanical signals into a chemical response. This presentation attempts to place the potential molecular mediators of mechanotransduction within the context of the structural complexity of living cells.

bullwinkle and shark regulate dorsal-appendage morphogenesis in Drosophila oogenesis.

PubMed

Tran, David H; Berg, Celeste A

2003-12-01

bullwinkle (bwk) regulates embryonic anteroposterior patterning and, through a novel germline-to-soma signal, morphogenesis of the eggshell dorsal appendages. We screened for dominant modifiers of the bullwinkle mooseantler eggshell phenotype and identified shark, which encodes an SH2-domain, ankyrin-repeat tyrosine kinase. At the onset of dorsal-appendage formation, shark is expressed in a punctate pattern in the squamous stretch cells overlying the nurse cells. Confocal microscopy with cell-type-specific markers demonstrates that the stretch cells act as a substrate for the migrating dorsal-appendage-forming cells and extend cellular projections towards them. Mosaic analyses reveal that shark is required in follicle cells for cell migration and chorion deposition. Proper shark RNA expression in the stretch cells requires bwk activity, while restoration of shark expression in the stretch cells suppresses the bwk dorsal-appendage phenotype. These results suggest that shark plays an important downstream role in the bwk-signaling pathway. Candidate testing implicates Src42A in a similar role, suggesting conservation with a vertebrate signaling pathway involving non-receptor tyrosine kinases.

Actin capping protein CAPZB regulates cell morphology, differentiation, and neural crest migration in craniofacial morphogenesis†

PubMed Central

Mukherjee, Kusumika; Ishii, Kana; Pillalamarri, Vamsee; Kammin, Tammy; Atkin, Joan F.; Hickey, Scott E.; Xi, Qiongchao J.; Zepeda, Cinthya J.; Gusella, James F.; Talkowski, Michael E.; Morton, Cynthia C.; Maas, Richard L.; Liao, Eric C.

2016-01-01

CAPZB is an actin-capping protein that caps the growing end of F-actin and modulates the cytoskeleton and tethers actin filaments to the Z-line of the sarcomere in muscles. Whole-genome sequencing was performed on a subject with micrognathia, cleft palate and hypotonia that harbored a de novo, balanced chromosomal translocation that disrupts the CAPZB gene. The function of capzb was analyzed in the zebrafish model. capzb−/− mutants exhibit both craniofacial and muscle defects that recapitulate the phenotypes observed in the human subject. Loss of capzb affects cell morphology, differentiation and neural crest migration. Differentiation of both myogenic stem cells and neural crest cells requires capzb. During palate morphogenesis, defective cranial neural crest cell migration in capzb−/− mutants results in loss of the median cell population, creating a cleft phenotype. capzb is also required for trunk neural crest migration, as evident from melanophores disorganization in capzb−/− mutants. In addition, capzb over-expression results in embryonic lethality. Therefore, proper capzb dosage is important during embryogenesis, and regulates both cell behavior and tissue morphogenesis. PMID:26758871

The Petunia GRAS Transcription Factor ATA/RAM1 Regulates Symbiotic Gene Expression and Fungal Morphogenesis in Arbuscular Mycorrhiza1

PubMed Central

Rich, Mélanie K.

2015-01-01

Arbuscular mycorrhiza (AM) is a mutual symbiosis that involves a complex symbiotic interface over which nutrients are exchanged between the plant host and the AM fungus. Dozens of genes in the host are required for the establishment and functioning of the interaction, among them nutrient transporters that mediate the uptake of mineral nutrients delivered by the fungal arbuscules. We have isolated in a genetic mutant screen a petunia (Petunia hybrida) GIBBERELLIC ACID INSENSITIVE, REPRESSOR of GIBBERELLIC ACID INSENSITIVE, and SCARECROW (GRAS)-type transcription factor, ATYPICAL ARBUSCULE (ATA), that acts as the central regulator of AM-related genes and is required for the morphogenesis of arbuscules. Forced mycorrhizal inoculations from neighboring wild-type plants revealed an additional role of ATA in restricting mycorrhizal colonization of the root meristem. The lack of ATA, which represents the ortholog of REQUIRED FOR ARBUSCULAR MYCORRHIZA1 in Medicago truncatula, renders the interaction completely ineffective, hence demonstrating the central role of AM-related genes for arbuscule development and function. PMID:25971550

The Petunia GRAS Transcription Factor ATA/RAM1 Regulates Symbiotic Gene Expression and Fungal Morphogenesis in Arbuscular Mycorrhiza.

PubMed

Rich, Mélanie K; Schorderet, Martine; Bapaume, Laure; Falquet, Laurent; Morel, Patrice; Vandenbussche, Michiel; Reinhardt, Didier

2015-07-01

Arbuscular mycorrhiza (AM) is a mutual symbiosis that involves a complex symbiotic interface over which nutrients are exchanged between the plant host and the AM fungus. Dozens of genes in the host are required for the establishment and functioning of the interaction, among them nutrient transporters that mediate the uptake of mineral nutrients delivered by the fungal arbuscules. We have isolated in a genetic mutant screen a petunia (Petunia hybrida) Gibberellic Acid Insensitive, Repressor of Gibberellic Acid Insensitive, and Scarecrow (GRAS)-type transcription factor, Atypical Arbuscule (ATA), that acts as the central regulator of AM-related genes and is required for the morphogenesis of arbuscules. Forced mycorrhizal inoculations from neighboring wild-type plants revealed an additional role of ATA in restricting mycorrhizal colonization of the root meristem. The lack of ATA, which represents the ortholog of Required For Arbuscular Mycorrhiza1 in Medicago truncatula, renders the interaction completely ineffective, hence demonstrating the central role of AM-related genes for arbuscule development and function. © 2015 American Society of Plant Biologists. All Rights Reserved.

Secretion of protein disulphide isomerase AGR2 confers tumorigenic properties

PubMed Central

Fessart, Delphine; Domblides, Charlotte; Avril, Tony; Eriksson, Leif A; Begueret, Hugues; Pineau, Raphael; Malrieux, Camille; Dugot-Senant, Nathalie; Lucchesi, Carlo; Chevet, Eric; Delom, Frederic

2016-01-01

The extracellular matrix (ECM) plays an instrumental role in determining the spatial orientation of epithelial polarity and the formation of lumens in glandular tissues during morphogenesis. Here, we show that the Endoplasmic Reticulum (ER)-resident protein anterior gradient-2 (AGR2), a soluble protein-disulfide isomerase involved in ER protein folding and quality control, is secreted and interacts with the ECM. Extracellular AGR2 (eAGR2) is a microenvironmental regulator of epithelial tissue architecture, which plays a role in the preneoplastic phenotype and contributes to epithelial tumorigenicity. Indeed, eAGR2, is secreted as a functionally active protein independently of its thioredoxin-like domain (CXXS) and of its ER-retention domain (KTEL), and is sufficient, by itself, to promote the acquisition of invasive and metastatic features. Therefore, we conclude that eAGR2 plays an extracellular role independent of its ER function and we elucidate this gain-of-function as a novel and unexpected critical ECM microenvironmental pro-oncogenic regulator of epithelial morphogenesis and tumorigenesis. DOI: http://dx.doi.org/10.7554/eLife.13887.001 PMID:27240165

Newt tail regeneration: a model for gravity-dependent morphogenesis and clues to the molecular mechanisms involved.

NASA Astrophysics Data System (ADS)

Radugina, Elena A.; Almeida, Eduardo; Grigoryan, Eleonora

Gravity alterations are widely recognized to influence living systems. They may cause temporary or permanent effects on physiology and development at different levels, from gene expression to morphogenesis. However, the molecular mechanisms underlying these effects are often unclear, and adequate model systems to study them are required. To address this problem we developed a new experimental model of how gravity affects morphogenesis during tail regeneration in the newt Pleurodeles waltl. The effects of increased gravity on newt tail morphogenesis were first documented in two joint Russian-US NASA spaceflight experiments in the Russian Foton-M2 (2005) and Foton-M3 (2007) missions. In these experiments the shape of newt tail regenerate was found to depend on the gravity level, being dorso-ventrally symmetrical in microgravity and in neutrally-buoyant aquarium controls, versus hook-like and bent downward in 1g controls. These 1g controls were conducted in spaceflight habitats using a water-saturated PVA sponge mat. These results were reproducible in multiple spaceflight, and ground laboratory studies, both in the US at NASA ARC and in Russia at IDB RAS, and were characterized in detail using morphometry and histology approaches. The role of hypergravity in shaping morphogenesis was confirmed at NASA ARC with an experiment in the ISS Testbed 8-foot diameter centrifuge operating at 2g. Animals that experienced two-week centrifugation (the period of time used in the Foton flights) developed the same hook-like regenerates as 1g controls, and morphometric analysis revealed no significant difference between 1g and 2g groups, however both were significantly different from aquarium controls. We hypothesize that exposure to 1g or 2g during tail morphogenesis constitutes excessive loading for newts that are adapted to microgravity-like conditions in their aquatic habitat. Because Heat Shock Proteins (HSPs) are stress-induced molecules that respond to a broad variety of factors and are expressed during development, we hypothesized they may play a role newt tail regenerative morphogenesis under altered g-levels. Specifically there is increasing evidence for HSPs expression changes as a result of hyper-and microgravity. HSPs are also expressed throughout regeneration, rather than just after surgery. To test this hypothesis we performed heat shock on intact and regenerating newts and collected tail tissues. In these experiments we observed that some tails had uplifted tips while others mimicked hook-like regenerates at 1g or 2g. These findings suggest that heat shock, and HSPs induction, may be involved in the mechanism responsible for gravity effects on morphogenesis, or at least interact with them. Current work underway is focused on analyzing the expression of mRNA and localization of proteins for two members of the group, Hsp70 and Hsp90. In summary, we developed and characterized a new practical animal model in which gravity mechanostimulation at 1g, versus unloading in aquaria, causes prominent effects on newt tail regenerative morphogenesis. This model can be achieved without the use of a centrifuge, significantly simplifying its research applications. Initial results using this model suggest that induction of HSPs may be involved in gravity regulation of newt tail regenerative morphogenesis. Further research based on this simple model may help to unravel mechanisms of gravity influence relevant not only to newt tail regeneration, but also to a broad range of other biological processes in amphibian models.

PrkC-mediated phosphorylation of overexpressed YvcK protein regulates PBP1 protein localization in Bacillus subtilis mreB mutant cells.

PubMed

Foulquier, Elodie; Pompeo, Frédérique; Freton, Céline; Cordier, Baptiste; Grangeasse, Christophe; Galinier, Anne

2014-08-22

The YvcK protein has been shown to be necessary for growth under gluconeogenic conditions in Bacillus subtilis. Amazingly, its overproduction rescues growth and morphology defects of the actin-like protein MreB deletion mutant by restoration of PBP1 localization. In this work, we observed that YvcK was phosphorylated at Thr-304 by the protein kinase PrkC and that phosphorylated YvcK was dephosphorylated by the cognate phosphatase PrpC. We show that neither substitution of this threonine with a constitutively phosphorylated mimicking glutamic acid residue or a phosphorylation-dead mimicking alanine residue nor deletion of prkC or prpC altered the ability of B. subtilis to grow under gluconeogenic conditions. However, we observed that a prpC mutant and a yvcK mutant were more sensitive to bacitracin compared with the WT strain. In addition, the bacitracin sensitivity of strains in which YvcK Thr-304 was replaced with either an alanine or a glutamic acid residue was also affected. We also analyzed rescue of the mreB mutant strain by overproduction of YvcK in which the phosphorylation site was substituted. We show that YvcK T304A overproduction did not rescue the mreB mutant aberrant morphology due to PBP1 mislocalization. The same observation was made in an mreB prkC double mutant overproducing YvcK. Altogether, these data show that YvcK may have two distinct functions: 1) in carbon source utilization independent of its phosphorylation level and 2) in cell wall biosynthesis and morphogenesis through its phosphorylation state. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Candida albicans ISW2 Regulates Chlamydospore Suspensor Cell Formation and Virulence In Vivo in a Mouse Model of Disseminated Candidiasis

PubMed Central

Lionakis, Michail S.; Nickerson, Kenneth W.

2016-01-01

Formation of chlamydospores by Candida albicans was an established medical diagnostic test to confirm candidiasis before the molecular era. However, the functional role and pathological relevance of this in vitro morphological transition to pathogenesis in vivo remain unclear. We compared the physical properties of in vitro-induced chlamydospores with those of large C. albicans cells purified by density gradient centrifugation from Candida-infected mouse kidneys. The morphological and physical properties of these cells in kidneys of mice infected intravenously with wild type C. albicans confirmed that chlamydospores can form in infected kidneys. A previously reported chlamydospore-null Δisw2/Δisw2 mutant was used to investigate its role in virulence and chlamydospore induction. Virulence of the Δisw2/Δisw2 mutant strain was reduced 3.4-fold compared to wild type C. albicans or the ISW2 reconstituted strain. Altered host inflammatory reactions to the null mutant further indicate that ISW2 is a virulence factor in C. albicans. ISW2 deletion abolished chlamydospore formation within infected mouse kidneys, whereas the reconstituted strain restored chlamydospore formation in kidneys. Under chlamydospore inducing conditions in vitro, deletion of ISW2 significantly delayed chlamydospore formation, and those late induced chlamydospores lacked associated suspensor cells while attaching laterally to hyphae via novel spore-hypha septa. Our findings establish the induction of chlamydospores by C. albicans during mouse kidney colonization. Our results indicate that ISW2 is not strictly required for chlamydospores formation but is necessary for suspensor cell formation. The importance of ISW2 in chlamydospore morphogenesis and virulence may lead to additional insights into morphological differentiation and pathogenesis of C. albicans in the host microenvironment. PMID:27727302

Dermal Blimp1 Acts Downstream of Epidermal TGFβ and Wnt/β-Catenin to Regulate Hair Follicle Formation and Growth.

PubMed

Telerman, Stephanie B; Rognoni, Emanuel; Sequeira, Inês; Pisco, Angela Oliveira; Lichtenberger, Beate M; Culley, Oliver J; Viswanathan, Priyalakshmi; Driskell, Ryan R; Watt, Fiona M

2017-11-01

B-lymphocyte-induced maturation protein 1 (Blimp1) is a transcriptional repressor that regulates cell growth and differentiation in multiple tissues, including skin. Although in the epidermis Blimp1 is important for keratinocyte and sebocyte differentiation, its role in dermal fibroblasts is unclear. Here we show that Blimp1 is dynamically regulated in dermal papilla cells during hair follicle (HF) morphogenesis and the postnatal hair cycle, preceding dermal Wnt/β-catenin activation. Blimp1 ablation in E12.5 mouse dermal fibroblasts delayed HF morphogenesis and growth and prevented new HF formation after wounding. By combining targeted quantitative PCR screens with bioinformatic analysis and experimental validation we demonstrated that Blimp1 is both a target and a mediator of key dermal papilla inductive signaling pathways including transforming growth factor-β and Wnt/β-catenin. Epidermal overexpression of stabilized β-catenin was able to override the HF defects in Blimp1 mutant mice, underlining the close reciprocal relationship between the dermal papilla and adjacent HF epithelial cells. Overall, our study reveals the functional role of Blimp1 in promoting the dermal papilla inductive signaling cascade that initiates HF growth. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

RNAi-Mediated Reverse Genetic Screen Identified Drosophila Chaperones Regulating Eye and Neuromuscular Junction Morphology.

PubMed

Raut, Sandeep; Mallik, Bhagaban; Parichha, Arpan; Amrutha, Valsakumar; Sahi, Chandan; Kumar, Vimlesh

2017-07-05

Accumulation of toxic proteins in neurons has been linked with the onset of neurodegenerative diseases, which in many cases are characterized by altered neuronal function and synapse loss. Molecular chaperones help protein folding and the resolubilization of unfolded proteins, thereby reducing the protein aggregation stress. While most of the chaperones are expressed in neurons, their functional relevance remains largely unknown. Here, using bioinformatics analysis, we identified 95 Drosophila chaperones and classified them into seven different classes. Ubiquitous actin5C -Gal4-mediated RNAi knockdown revealed that ∼50% of the chaperones are essential in Drosophila Knocking down these genes in eyes revealed that ∼30% of the essential chaperones are crucial for eye development. Using neuron-specific knockdown, immunocytochemistry, and robust behavioral assays, we identified a new set of chaperones that play critical roles in the regulation of Drosophila NMJ structural organization. Together, our data present the first classification and comprehensive analysis of Drosophila chaperones. Our screen identified a new set of chaperones that regulate eye and NMJ morphogenesis. The outcome of the screen reported here provides a useful resource for further elucidating the role of individual chaperones in Drosophila eye morphogenesis and synaptic development. Copyright © 2017 Raut et al.

ROP GTPase-mediated auxin signaling regulates pavement cell interdigitation in Arabidopsis thaliana.

PubMed

Lin, Deshu; Ren, Huibo; Fu, Ying

2015-01-01

In multicellular plant organs, cell shape formation depends on molecular switches to transduce developmental or environmental signals and to coordinate cell-to-cell communication. Plants have a specific subfamily of the Rho GTPase family, usually called Rho of Plants (ROP), which serve as a critical signal transducer involved in many cellular processes. In the last decade, important advances in the ROP-mediated regulation of plant cell morphogenesis have been made by using Arabidopsis thaliana leaf and cotyledon pavement cells. Especially, the auxin-ROP signaling networks have been demonstrated to control interdigitated growth of pavement cells to form jigsaw-puzzle shapes. Here, we review findings related to the discovery of this novel auxin-signaling mechanism at the cell surface. This signaling pathway is to a large extent independent of the well-known Transport Inhibitor Response (TIR)-Auxin Signaling F-Box (AFB) pathway, and instead requires Auxin Binding Protein 1 (ABP1) interaction with the plasma membrane-localized, transmembrane kinase (TMK) receptor-like kinase to regulate ROP proteins. Once activated, ROP influences cytoskeletal organization and inhibits endocytosis of the auxin transporter PIN1. The present review focuses on ROP signaling and its self-organizing feature allowing ROP proteins to serve as a bustling signal decoder and integrator for plant cell morphogenesis. © 2014 Institute of Botany, Chinese Academy of Sciences.

Protocol for efficient regulation of in vitro morphogenesis in einkorn (Triticum monococcum L.), a recalcitrant diploid wheat species

PubMed Central

Miroshnichenko, Dmitry; Chaban, Inna; Chernobrovkina, Mariya; Dolgov, Sergey

2017-01-01

Einkorn (Triticum monococcum L.) is A-genome diploid wheat that has a potential to become a useful model for understanding the biology and genomics in Triticeae. Unfortunately, the application of modern technologies such as genetic engineering, RNAi-based gene silencing and genome editing is not available for einkorn as there is no efficient in vitro tissue culture and plant regeneration system. In the present study an efficient and simple protocol for plant regeneration via direct or indirect somatic embryogenesis and organogenesis has been developed. Various auxins used as sole inductors in einkorn displayed low effect for morphogenesis (0–8%) and plant regeneration (1–2 shoots per explant). The addition of Daminozide, the inhibitor of biosynthesis of gibberellins, together with auxin significantly improved the formation of morphogenic structures, especially when Dicamba (51.4%) and Picloram (56.6%) were used for combination; furthermore, the simultaneous addition of cytokinin into induction medium significantly promoted in vitro performance. Among the tested cytokinins, the urea-type substances, such as TDZ and CPPU were more effective than the adenine type ones, BA and Zeatin, for the regulation of morphogenesis; especially, TDZ was more effective than CPPU for shoot formation (11.73 vs. 7.04 per regenerating callus). The highest morphogenic response of 90.2% with the production of more than 10 shoots per initial explant was observed when 3.0 mg/L Dicamba, 50.0 mg/L Daminozide and 0.25 mg/L TDZ were combined together. Along with the identification of appropriate induction medium, the optimal developmental stage for einkorn was found as partially transparent immature embryo in size of around 1.0 mm. Although in the present study the critical balance between plant growth regulators was established for einkorn only, we assume that further the proposed strategy could be successfully applied to other recalcitrant cereal species and genotypes. PMID:28273182

Scribble is required for normal epithelial cell–cell contacts and lumen morphogenesis in the mammalian lung

PubMed Central

Yates, Laura L.; Schnatwinkel, Carsten; Hazelwood, Lee; Chessum, Lauren; Paudyal, Anju; Hilton, Helen; Romero, M. Rosario; Wilde, Jonathan; Bogani, Debora; Sanderson, Jeremy; Formstone, Caroline; Murdoch, Jennifer N.; Niswander, Lee A.; Greenfield, Andy; Dean, Charlotte H.

2013-01-01

During lung development, proper epithelial cell arrangements are critical for the formation of an arborized network of tubes. Each tube requires a lumen, the diameter of which must be tightly regulated to enable optimal lung function. Lung branching and lumen morphogenesis require close epithelial cell–cell contacts that are maintained as a result of adherens junctions, tight junctions and by intact apical–basal (A/B) polarity. However, the molecular mechanisms that maintain epithelial cohesion and lumen diameter in the mammalian lung are unknown. Here we show that Scribble, a protein implicated in planar cell polarity (PCP) signalling, is necessary for normal lung morphogenesis. Lungs of the Scrib mouse mutant Circletail (Crc) are abnormally shaped with fewer airways, and these airways often lack a visible, ‘open’ lumen. Mechanistically we show that Scrib genetically interacts with the core PCP gene Vangl2 in the developing lung and that the distribution of PCP pathway proteins and Rho mediated cytoskeletal modification is perturbed in ScribCrc/Crc lungs. However A/B polarity, which is disrupted in Drosophila Scrib mutants, is largely unaffected. Notably, we find that Scrib mediates functions not attributed to other PCP proteins in the lung. Specifically, Scrib localises to both adherens and tight junctions of lung epithelia and knockdown of Scrib in lung explants and organotypic cultures leads to reduced cohesion of lung epithelial cells. Live imaging of Scrib knockdown lungs shows that Scrib does not affect bud bifurcation, as previously shown for the PCP protein Celsr1, but is required to maintain epithelial cohesion. To understand the mechanism leading to reduced cell–cell association, we show that Scrib associates with β-catenin in embryonic lung and the sub-cellular distribution of adherens and tight junction proteins is perturbed in mutant lung epithelia. Our data reveal that Scrib is required for normal lung epithelial organisation and lumen morphogenesis by maintaining cell–cell contacts. Thus we reveal novel and important roles for Scrib in lung development operating via the PCP pathway, and in regulating junctional complexes and cell cohesion. PMID:23195221

Wnt-regulated dynamics of positional information in zebrafish somitogenesis

PubMed Central

Bajard, Lola; Morelli, Luis G.; Ares, Saúl; Pécréaux, Jacques; Jülicher, Frank; Oates, Andrew C.

2014-01-01

How signaling gradients supply positional information in a field of moving cells is an unsolved question in patterning and morphogenesis. Here, we ask how a Wnt signaling gradient regulates the dynamics of a wavefront of cellular change in a flow of cells during somitogenesis. Using time-controlled perturbations of Wnt signaling in the zebrafish embryo, we changed segment length without altering the rate of somite formation or embryonic elongation. This result implies specific Wnt regulation of the wavefront velocity. The observed Wnt signaling gradient dynamics and timing of downstream events support a model for wavefront regulation in which cell flow plays a dominant role in transporting positional information. PMID:24595291

[Apoptosis and pathological process].

PubMed

Rami, Mukhammed Salim Iusef

2007-01-01

Apoptosis (programmed cell death) occurs normally for maitenance of tissue homeostasis and play an important role in morphogenesis, embriogenesis and tissue growth. On the other hand, apoptosis may be involved in different pathological processes such as malignancy, infectious diseases and autoimmune disorders. Apoptosis is regulated by various mediators. Caspases, death receptors, mitochondria, Bcl-2 protoncogenes and tumor supressor genes are considered to be the most important of them. Advance in apoptosis regulation research suggests enormouse facilities for therapy of wide range of human illnesses.

Role of the Talaromyces marneffei (Penicillium marneffei) sakA gene in nitrosative stress response, conidiation and red pigment production.

PubMed

Nimmanee, Panjaphorn; Tam, Emily W T; Woo, Patrick C Y; Vanittanakom, Pramote; Vanittanakom, Nongnuch

2017-04-01

Stress-activated MAPK pathways are systems used to regulate the stress adaptation of most fungi. It has been shown that in Talaromyces marneffei (Penicillium marneffei), a pathogenic dimorphic fungus, the sakA gene is involved, not only in tolerance against oxidative and heat stresses, but also in playing a role in asexual development, yeast cell generation in vitro and survival inside macrophage cell lines. In this study, the role of the T. marneffei sakA gene on the nitrosative stress response and the regulation of gene expression were investigated. The susceptibility of the sakA mutant to NaNO2 was investigated using drop dilution assay and the expression of genes of interest were determined by RT-PCR, comparing them to the wild-type and complemented strains. The results demonstrated that the T. marneffei sakA gene played a role in the stress response to NaNO2, the expression of genes functioning in conidial development (brlA, abaA and wetA) and red pigment biosynthesis (pks3, rp1, rp2 and rp3). These findings suggest that T. marneffei sakA is broadly involved in a wide variety of cell activities, including stress response, cell morphogenesis, asexual development and pigmentation. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Msx-2 expression and glucocorticoid-induced overexpression in embryonic mouse submandibular glands.

PubMed

Jaskoll, T; Luo, W; Snead, M L

1998-01-01

It is well known that the process of branching morphogenesis requires epithelial-mesenchymal interactions. One outstanding model for the study of tissue interactions during branching morphogenesis is the embryonic mouse submandibular gland (SMG). Although it has been clearly demonstrated that the branching pattern is dependent on interactions between the epithelium and the surrounding mesenchyme, little is known about the molecular mechanism underlying the branching process. One group of transcription factors that likely participates in the control of epithelial-mesenchymal inductive interactions are the Msx-class of homeodomain-containing proteins. In this paper, we focus on Msx-2 because its developmental expression is correlated with inductive interactions, suggesting that Msx-2 may play a functional role during cell-cell interactions. We demonstrate the expression of Msx-2 mRNA and protein to be primarily in the branching epithelia with progressive embryonic (E13 to E15) SMG development and, to a lesser extent, in the mesenchyme. We also show that Msx-2 is expressed by embryonic SMG primordia cultured under defined conditions. In addition, to begin to delineate a functional role for Msx-2, we employed an experimental strategy by using exogenous glucocorticoid (CORT) treatment of embryonic SMGs in vitro and in vivo to significantly enhance branching morphogenesis and evaluate the effect of CORT treatment on embryonic SMG Msx-2 expression. A marked increase in Msx-2 transcripts and protein is detected with in vitro and in vivo CORT treatment. Our studies indicate that one mechanism of CORT regulation of salivary gland morphogenesis is likely through the modulation of Msx-2 gene expression.

Loss of laminin alpha 1 results in multiple structural defects and divergent effects on adhesion during vertebrate optic cup morphogenesis

PubMed Central

Bryan, Chase D.; Chien, Chi-Bin; Kwan, Kristen M.

2016-01-01

The vertebrate eye forms via a complex set of morphogenetic events. The optic vesicle evaginates and undergoes transformative shape changes to form the optic cup, in which neural retina and retinal pigmented epithelium enwrap the lens. It has long been known that a complex, glycoprotein-rich extracellular matrix layer surrounds the developing optic cup throughout the process, yet the functions of the matrix and its specific molecular components have remained unclear. Previous work established a role for laminin extracellular matrix in particular steps of eye development, including optic vesicle evagination, lens differentiation, and retinal ganglion cell polarization, yet it is unknown what role laminin might play in the early process of optic cup formation subsequent to the initial step of optic vesicle evagination. Here, we use the zebrafish lama1 mutant (lama1UW1) to determine the function of laminin during optic cup morphogenesis. Using live imaging, we find, surprisingly, that loss of laminin leads to divergent effects on focal adhesion assembly in a spatiotemporally-specific manner, and that laminin is required for multiple steps of optic cup morphogenesis, including optic stalk constriction, invagination, and formation of a spherical lens. Laminin is not required for single cell behaviors and changes in cell shape. Rather, in lama1UW1 mutants, loss of epithelial polarity and altered adhesion lead to defective tissue architecture and formation of a disorganized retina. These results demonstrate that the laminin extracellular matrix plays multiple critical roles regulating adhesion and polarity to establish and maintain tissue structure during optic cup morphogenesis. PMID:27339294

The mechanics behind plant development.

PubMed

Hamant, Olivier; Traas, Jan

2010-01-01

Morphogenesis in living organisms relies on the integration of both biochemical and mechanical signals. During the last decade, attention has been mainly focused on the role of biochemical signals in patterning and morphogenesis, leaving the contribution of mechanics largely unexplored. Fortunately, the development of new tools and approaches has made it possible to re-examine these processes. In plants, shape is defined by two local variables: growth rate and growth direction. At the level of the cell, these variables depend on both the cell wall and turgor pressure. Multidisciplinary approaches have been used to understand how these cellular processes are integrated in the growing tissues. These include quantitative live imaging to measure growth rate and direction in tissues with cellular resolution. In parallel, stress patterns have been artificially modified and their impact on strain and cell behavior been analysed. Importantly, computational models based on analogies with continuum mechanics systems have been useful in interpreting the results. In this review, we will discuss these issues focusing on the shoot apical meristem, a population of stem cells that is responsible for the initiation of the aerial organs of the plant.

The Genome of S-PM2, a “Photosynthetic” T4-Type Bacteriophage That Infects Marine Synechococcus Strains

PubMed Central

Mann, Nicholas H.; Clokie, Martha R. J.; Millard, Andrew; Cook, Annabel; Wilson, William H.; Wheatley, Peter J.; Letarov, Andrey; Krisch, H. M.

2005-01-01

Bacteriophage S-PM2 infects several strains of the abundant and ecologically important marine cyanobacterium Synechococcus. A large lytic phage with an isometric icosahedral head, S-PM2 has a contractile tail and by this criterion is classified as a myovirus (1). The linear, circularly permuted, 196,280-bp double-stranded DNA genome of S-PM2 contains 37.8% G+C residues. It encodes 239 open reading frames (ORFs) and 25 tRNAs. Of these ORFs, 19 appear to encode proteins associated with the cell envelope, including a putative S-layer-associated protein. Twenty additional S-PM2 ORFs have homologues in the genomes of their cyanobacterial hosts. There is a group I self-splicing intron within the gene encoding the D1 protein. A total of 40 ORFs, organized into discrete clusters, encode homologues of T4 proteins involved in virion morphogenesis, nucleotide metabolism, gene regulation, and DNA replication and repair. The S-PM2 genome encodes a few surprisingly large (e.g., 3,779 amino acids) ORFs of unknown function. Our analysis of the S-PM2 genome suggests that many of the unknown S-PM2 functions may be involved in the adaptation of the metabolism of the host cell to the requirements of phage infection. This hypothesis originates from the identification of multiple phage-mediated modifications of the host's photosynthetic apparatus that appear to be essential for maintaining energy production during the lytic cycle. PMID:15838046

Genome Sequence of African Swine Fever Virus BA71, the Virulent Parental Strain of the Nonpathogenic and Tissue-Culture Adapted BA71V

PubMed Central

Rodríguez, Javier M.; Moreno, Leticia Tais; Alejo, Alí; Lacasta, Anna; Rodríguez, Fernando; Salas, María L.

2015-01-01

The strain BA71V has played a key role in African swine fever virus (ASFV) research. It was the first genome sequenced, and remains the only genome completely determined. A large part of the studies on the function of ASFV genes, viral transcription, replication, DNA repair and morphogenesis, has been performed using this model. This avirulent strain was obtained by adaptation to grow in Vero cells of the highly virulent BA71 strain. We report here the analysis of the genome sequence of BA71 in comparison with that of BA71V. They possess the smallest genomes for a virulent or an attenuated ASFV, and are essentially identical except for a relatively small number of changes. We discuss the possible contribution of these changes to virulence. Analysis of the BA71 sequence allowed us to identify new similarities among ASFV proteins, and with database proteins including two ASFV proteins that could function as a two-component signaling network. PMID:26618713

Control of Arabidopsis leaf morphogenesis through regulation of the YABBY and KNOX families of transcription factors

USDA-ARS?s Scientific Manuscript database

The patterning of initiating organs along specific axes of polarity is critical for the proper development of all higher organisms. Plant lateral organs, such as leaves, are derived from the shoot apical meristems located at the growing tips. After initiation, the leaf primordia of species such as A...

Effect of Levonorgestrel (NORPLANT) on the Immune Regulation of Bone Morphogenesis in Calvarial Cultures from the Laboratory Mouse (Mus muscularis).

DTIC Science & Technology

1995-10-01

continually releases a synthetic progestin, levonorgestrel , for five years. In order to assess the impact of levonorgestrel on bone cells, murine calvarial...cell cultures were harvested, grown to confluence and treated with levonorgestrel , progesterone and estrogen. The majority of the cells grown in these

Deletion of the "OPHN1" Gene Detected by aCGH

ERIC Educational Resources Information Center

Madrigal, I.; Rodriguez-Revenga, L.; Badenas, C.; Sanchez, A.; Mila, M.

2008-01-01

Background: The oligophrenin 1 gene ("OPHN1") is an Rho-GTPase-activating protein involved in the regulation of the G-protein cycle required for dendritic spine morphogenesis. Mutations in this gene are implicated in X-linked mental retardation (XLMR). Methods: We report a deletion spanning exons 21 and 22 of the "OPHN1" gene identified by a…

Asymmetric cell division of stem cells in the lung and other systems

PubMed Central

Berika, Mohamed; Elgayyar, Marwa E.; El-Hashash, Ahmed H. K.

2014-01-01

New insights have been added to identification, behavior and cellular properties of embryonic and tissue-specific stem cells over the last few years. The modes of stem cell division, asymmetric vs. symmetric, are tightly regulated during development and regeneration. The proper choice of a stem cell to divide asymmetrically or symmetrically has great consequences for development and disease because inappropriate asymmetric division disrupts organ morphogenesis, whereas uncontrolled symmetric division induces tumorigenesis. Therefore, understanding the behavior of lung stem cells could identify innovative solutions for restoring normal morphogenesis and/or regeneration of different organs. In this concise review, we describe recent studies in our laboratory about the mode of division of lung epithelial stem cells. We also compare asymmetric cell division (ACD) in the lung stem cells with other tissues in different organisms. PMID:25364740

Apical constriction: themes and variations on a cellular mechanism driving morphogenesis

PubMed Central

Martin, Adam C.; Goldstein, Bob

2014-01-01

Apical constriction is a cell shape change that promotes tissue remodeling in a variety of homeostatic and developmental contexts, including gastrulation in many organisms and neural tube formation in vertebrates. In recent years, progress has been made towards understanding how the distinct cell biological processes that together drive apical constriction are coordinated. These processes include the contraction of actin-myosin networks, which generates force, and the attachment of actin networks to cell-cell junctions, which allows forces to be transmitted between cells. Different cell types regulate contractility and adhesion in unique ways, resulting in apical constriction with varying dynamics and subcellular organizations, as well as a variety of resulting tissue shape changes. Understanding both the common themes and the variations in apical constriction mechanisms promises to provide insight into the mechanics that underlie tissue morphogenesis. PMID:24803648

Dynamin 2 regulation of integrin endocytosis, but not VEGF signaling, is crucial for developmental angiogenesis

PubMed Central

Lee, Monica Y.; Skoura, Athanasia; Park, Eon Joo; Landskroner-Eiger, Shira; Jozsef, Levente; Luciano, Amelia K.; Murata, Takahisa; Pasula, Satish; Dong, Yunzhou; Bouaouina, Mohamed; Calderwood, David A.; Ferguson, Shawn M.; De Camilli, Pietro; Sessa, William C.

2014-01-01

Here we show that dynamin 2 (Dnm2) is essential for angiogenesis in vitro and in vivo. In cultured endothelial cells lacking Dnm2, vascular endothelial growth factor (VEGF) signaling and receptor levels are augmented whereas cell migration and morphogenesis are impaired. Mechanistically, the loss of Dnm2 increases focal adhesion size and the surface levels of multiple integrins and reduces the activation state of β1 integrin. In vivo, the constitutive or inducible loss of Dnm2 in endothelium impairs branching morphogenesis and promotes the accumulation of β1 integrin at sites of failed angiogenic sprouting. Collectively, our data show that Dnm2 uncouples VEGF signaling from function and coordinates the endocytic turnover of integrins in a manner that is crucially important for angiogenesis in vitro and in vivo. PMID:24598168

N-myc regulates growth and fiber cell differentiation in lens development

PubMed Central

Cavalheiro, Gabriel R.; Matos-Rodrigues, Gabriel E.; Zhao, Yilin; Gomes, Anielle L.; Anand, Deepti; Predes, Danilo; de Lima, Silmara; Abreu, Jose G.; Zheng, Deyou; Lachke, Salil A.; Cvekl, Ales; Martins, Rodrigo A. P.

2017-01-01

Myc proto-oncogenes regulate diverse cellular processes during development, but their roles during morphogenesis of specific tissues are not fully understood. We found that c-myc regulates cell proliferation in mouse lens development and previous genome-wide studies suggested functional roles for N-myc in developing lens. Here, we examined the role of N-myc in mouse lens development. Genetic inactivation of N-myc in the surface ectoderm or lens vesicle impaired eye and lens growth, while "late" inactivation in lens fibers had no effect. Unexpectedly, defective growth of N-myc--deficient lenses was not associated with alterations in lens progenitor cell proliferation or survival. Notably, N-myc-deficient lens exhibited a delay in degradation of DNA in terminally differentiating lens fiber cells. RNA-sequencing analysis of N-myc--deficient lenses identified a cohort of down-regulated genes associated with fiber cell differentiation that included DNaseIIβ. Further, an integrated analysis of differentially expressed genes in N-myc-deficient lens using normal lens expression patterns of iSyTE, N-myc-binding motif analysis and molecular interaction data from the String database led to the derivation of an N-myc-based gene regulatory network in the lens. Finally, analysis of N-myc and c-myc double-deficient lens demonstrated that these Myc genes cooperate to drive lens growth prior to lens vesicle stage. Together, these findings provide evidence for exclusive and cooperative functions of Myc transcription factors in mouse lens development and identify novel mechanisms by which N-myc regulates cell differentiation during eye morphogenesis. PMID:28716713

WAVE2 regulates epithelial morphology and cadherin isoform switching through regulation of Twist and Abl.

PubMed

Bryce, Nicole S; Reynolds, Albert B; Koleske, Anthony J; Weaver, Alissa M

2013-01-01

Epithelial morphogenesis is a dynamic process that involves coordination of signaling and actin cytoskeletal rearrangements. We analyzed the contribution of the branched actin regulator WAVE2 in the development of 3-dimensional (3D) epithelial structures. WAVE2-knockdown (WAVE2-KD) cells formed large multi-lobular acini that continued to proliferate at an abnormally late stage compared to control acini. Immunostaining of the cell-cell junctions of WAVE2-KD acini revealed weak and heterogeneous E-cadherin staining despite little change in actin filament localization to the same junctions. Analysis of cadherin expression demonstrated a decrease in E-cadherin and an increase in N-cadherin protein and mRNA abundance in total cell lysates. In addition, WAVE2-KD cells exhibited an increase in the mRNA levels of the epithelial-mesenchymal transition (EMT)-associated transcription factor Twist1. KD of Twist1 expression in WAVE2-KD cells reversed the cadherin switching and completely rescued the aberrant 3D morphological phenotype. Activity of the WAVE2 complex binding partner Abl kinase was also increased in WAVE2-KD cells, as assessed by tyrosine phosphorylation of the Abl substrate CrkL. Inhibition of Abl with STI571 rescued the multi-lobular WAVE2-KD 3D phenotype whereas overexpression of Abl kinase phenocopied the WAVE2-KD phenotype. The WAVE2 complex regulates breast epithelial morphology by a complex mechanism involving repression of Twist1 expression and Abl kinase activity. These data reveal a critical role for WAVE2 complex in regulation of cellular signaling and epithelial morphogenesis.

The N- or C-terminal domains of DSH-2 can activate the C. elegans Wnt/β-catenin asymmetry pathway

PubMed Central

King, Ryan S.; Maiden, Stephanie L.; Hawkins, Nancy C.; Kidd, Ambrose R.; Kimble, Judith; Hardin, Jeff; Walston, Timothy D.

2015-01-01

Dishevelleds are modular proteins that lie at the crossroads of divergent Wnt signaling pathways. The DIX domain of dishevelleds modulates a β-catenin destruction complex, and thereby mediates cell fate decisions through differential activation of Tcf transcription factors. The DEP domain of dishevelleds mediates planar polarity of cells within a sheet through regulation of actin modulators. In Caenorhabditis elegans asymmetric cell fate decisions are regulated by asymmetric localization of signaling components in a pathway termed the Wnt/β-catenin asymmetry pathway. Which domain(s) of Disheveled regulate this pathway is unknown. We show that C. elegans embryos from dsh-2(or302) mutant mothers fail to successfully undergo morphogenesis, but transgenes containing either the DIX or the DEP domain of DSH-2 are sufficient to rescue the mutant phenotype. Embryos lacking zygotic function of SYS-1/β-catenin, WRM-1/β-catenin, or POP-1/Tcf show defects similar to dsh-2 mutants, including a loss of asymmetry in some cell fate decisions. Removal of two dishevelleds (dsh-2 and mig-5) leads to a global loss of POP-1 asymmetry, which can be rescued by addition of transgenes containing either the DIX or DEP domain of DSH-2. These results indicate that either the DIX or DEP domain of DSH-2 is capable of activating the Wnt/β-catenin asymmetry pathway and regulating anterior–posterior fate decisions required for proper morphogenesis. PMID:19298786

Conserved developmental alternative splicing of muscleblind-like (MBNL) transcripts regulates MBNL localization and activity.

PubMed

Terenzi, Fulvia; Ladd, Andrea N

2010-01-01

Muscleblind-like (MBNL) proteins have been shown to regulate pre-mRNA alternative splicing, and MBNL1 has been implicated in regulating fetal-to-adult transitions in alternative splicing in the heart. MBNL1 is highly conserved, exhibiting more than 95% identity at the amino acid level between birds and mammals. To investigate MBNL1 expression during embryonic heart development, we examined MBNL1 transcript and protein expression in the embryonic chicken heart from the formation of the primitive heart tube through cardiac morphogenesis (embryonic days 1.5 through 8). MBNL1 transcript levels remained steady throughout these stages, whereas MBNL1 protein levels increased and exhibited a shift in isoforms. MBNL1 has several alternatively spliced exons. Using RT-PCR, we determined that the inclusion of one of these, exon 5, decreases dramatically during cardiac morphogenesis. This developmental transition is conserved in mice. Functional analyses of MBNL1 isoforms containing or lacking exon 5-encoded sequences revealed that exon 5 is important for the regulation of the subcellular localization, RNA binding affinity, and alternative splicing activity of MBNL1 proteins. A second MBNL protein, MBNL2, is also expressed in the embryonic heart. We found that MBNL2 exon 5, which is paralogous to MBNL1 exon 5, is similarly regulated during embryonic heart development. Analysis of MBNL1 and MBNL2 transcripts in several embryonic tissues in chicken and mouse indicate that exon 5 alternative splicing is highly conserved and tissue-specific. Thus, we propose that conserved developmental stage- and tissue-specific alternative splicing of MBNL transcripts is an important mechanism by which MBNL activity is regulated during embryonic development.

Epidermal growth factor system is a physiological regulator of development of the mouse fetal submandibular gland and regulates expression of the alpha6-integrin subunit.

PubMed

Kashimata, M; Gresik, E W

1997-02-01

Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) regulate branching morphogenesis of fetal mouse submandibular gland (SMG) rudiments in vitro. The EGF system (EGF, TGF-alpha, and their shared receptor, EGFR) also regulates expression of integrins and their ligands in the extracellular matrix. We show here that inhibition of EGFR tyrosine-kinase activity by a tyrphostin retards in vitro development of SMGs. Using total RNA isolated from pooled SMGs taken from intact mouse fetuses, mRNA transcripts for EGF, TGF-alpha, and EGFR were detected by reverse transcription-polymerase chain reaction (RT-PCR), and age-dependent variations in the levels of these mRNA were quantitatively determined by nuclease protection assays. These findings suggest that the EGF system is operative in the in vivo development of this gland. alpha6-Integrin subunit was localized by immunofluorescence at the basal surface of epithelial cells. Branching morphogenesis of cultured SMG rudiments was inhibited by anti-alpha6 antibodies. Synthesis of alpha6-subunit in cultured SMGs, detected by metabolic labeling and immunoprecipitation, was increased by EGF and drastically reduced by tyrphostin. RT-PCR revealed that mRNAs for alpha6- and beta1- and beta4-integrin subunits are expressed at all ages between embryonic day 13 and postnatal day 7. These findings suggest that 1) the EGF system is a physiologic regulator of development of fetal mouse SMG, and 2) one mechanism by which it acts may be by regulating expression of integrins, which in turn control interaction of epithelial cells with the extracellular matrix.

Expression of Pleiotrophin in the Prostate is Androgen Regulated and it Functions as an Autocrine Regulator of Mesenchyme and Cancer Associated Fibroblasts and as a Paracrine Regulator of Epithelia

PubMed Central

Orr, Brigid; Vanpoucke, Griet; Grace, O Cathal; Smith, Lee; Anderson, Richard A; Riddick, Antony CP; Franco, Omar E; Hayward, Simon W; Thomson, Axel A

2011-01-01

BACKGROUND Androgens and paracrine signaling from mesenchyme/stroma regulate development and disease of the prostate, and gene profiling studies of inductive prostate mesenchyme have identified candidate molecules such as pleiotrophin (Ptn). METHODS Ptn transcripts and protein were localized by in situ and immunohistochemistry and Ptn mRNA was quantitated by Northern blot and qRT-PCR. Ptn function was examined by addition of hPTN protein to rat ventral prostate organ cultures, primary human fetal prostate fibroblasts, prostate cancer associated fibroblasts, and BPH1 epithelia. RESULTS During development, Ptn transcripts and protein were expressed in ventral mesenchymal pad (VMP) and prostatic mesenchyme. Ptn was localized to mesenchyme surrounding ductal epithelial tips undergoing branching morphogenesis, and was located on the surface of epithelia. hPTN protein stimulated branching morphogenesis and stromal and epithelial proliferation, when added to rat VP cultures, and also stimulated growth of fetal human prostate fibroblasts, prostate cancer associated fibroblasts, and BPH1 epithelia. PTN mRNA was enriched in patient-matched normal prostate fibroblasts versus prostate cancer associated fibroblasts. PTN also showed male enriched expression in fetal human male urethra versus female, and between wt male and ARKO male mice. Transcripts for PTN were upregulated by testosterone in fetal human prostate fibroblasts and organ cultures of female rat VMP. Ptn protein was increased by testosterone in organ cultures of female rat VMP and in rat male urethra compared to female. CONCLUSIONS Our data suggest that in the prostate Ptn functions as a regulator of both mesenchymal and epithelial proliferation, and that androgens regulate Ptn levels. Prostate 71:305–317, 2011. © 2010 Wiley-Liss, Inc. PMID:20812209

The DCL gene of tomato is required for chloroplast development and palisade cell morphogenesis in leaves.

PubMed

Keddie, J S; Carroll, B; Jones, J D; Gruissem, W

1996-08-15

The defective chloroplasts and leaves-mutable (dcl-m) mutation of tomato was identified in a Ds mutagenesis screen. This unstable mutation affects both chloroplast development and palisade cell morphogenesis in leaves. Mutant plants are clonally variegated as a result of somatic excision of Ds and have albino leaves with green sectors. Leaf midribs and stems are light green with sectors of dark green tissue but fruit and petals are wild-type in appearance. Within dark green sectors of dcl-m leaves, palisade cells are normal, whereas in albino areas of dcl-m leaves, palisade cells do not expand to become their characteristic columnar shape. The development of chloroplasts from proplastids in albino areas is apparently blocked at an early stage. DCL was cloned using Ds as a tag and encodes a novel protein of approximately 25 kDa, containing a chloroplast transit peptide and an acidic alpha-helical region. DCL protein was imported into chloroplasts in vitro and processed to a mature form. Because of the ubiquitous expression of DCL and the proplastid-like appearance of dcl-affected plastids, the DCL protein may regulate a basic and universal function of the plastid. The novel dcl-m phenotype suggests that chloroplast development is required for correct palisade cell morphogenesis during leaf development.

The metabolic response of Candida albicans to farnesol under hyphae-inducing conditions.

PubMed

Han, Ting-Li; Cannon, Richard D; Villas-Bôas, Silas G

2012-12-01

Farnesol is a quorum-sensing molecule (QSM) produced, and sensed, by the polymorphic fungus, Candida albicans. This cell-to-cell communication molecule is known to suppress the hyphal formation of C. albicans at high cell density. Despite many studies investigating the signalling mechanisms by which QSMs influence the morphogenesis of C. albicans, the downstream metabolic effect of these signalling pathways in response to farnesol-mediated morphogenesis remains obscure. Here, we have used metabolomics to investigate the metabolic response of C. albicans upon exposure to farnesol under hyphae-inducing conditions. We have found a general up-regulation of central carbon metabolic pathways when hyphal formation was suppressed by farnesol evidenced by a considerably larger number of central carbon metabolic intermediates detected under this condition at an overall lower intracellular level. By combining the metabolic profiles from farnesol-exposed cells with previous metabolomics data for C. albicans undergoing morphogenesis, we have identified several metabolic pathways that are likely to be associated with the morphogenetic process of C. albicans, as well as metabolic pathways such as those involved in lipid metabolism that appeared to be specifically affected by farnesol. Therefore, our results provide important new insights into the metabolic role of farnesol in C. albicans metabolism. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Deposition of collagen type I onto skeletal endothelium reveals a new role for blood vessels in regulating bone morphology

PubMed Central

Ben Shoham, Adi; Rot, Chagai; Stern, Tomer; Krief, Sharon; Akiva, Anat; Dadosh, Tali; Sabany, Helena; Lu, Yinhui; Kadler, Karl E.

2016-01-01

Recently, blood vessels have been implicated in the morphogenesis of various organs. The vasculature is also known to be essential for endochondral bone development, yet the underlying mechanism has remained elusive. We show that a unique composition of blood vessels facilitates the role of the endothelium in bone mineralization and morphogenesis. Immunostaining and electron microscopy showed that the endothelium in developing bones lacks basement membrane, which normally isolates the blood vessel from its surroundings. Further analysis revealed the presence of collagen type I on the endothelial wall of these vessels. Because collagen type I is the main component of the osteoid, we hypothesized that the bone vasculature guides the formation of the collagenous template and consequently of the mature bone. Indeed, some of the bone vessels were found to undergo mineralization. Moreover, the vascular pattern at each embryonic stage prefigured the mineral distribution pattern observed one day later. Finally, perturbation of vascular patterning by overexpressing Vegf in osteoblasts resulted in abnormal bone morphology, supporting a role for blood vessels in bone morphogenesis. These data reveal the unique composition of the endothelium in developing bones and indicate that vascular patterning plays a role in determining bone shape by forming a template for deposition of bone matrix. PMID:27621060

Fucus as a Model System to Study the Role of Auxin Transport and the Actin Cytoskeleton in Gravity Response

NASA Technical Reports Server (NTRS)

Muday, Gloria K.

2003-01-01

The overarching goal of this proposal was to examine the mechanisms for the cellular asymmetry in auxin transport proteins. As auxin transport polarity changes in response to reorientation of algal and plant cells relative to the gravity vector, it was critical to ask how auxin transport polarity is established and how this transport polarity may change in response to gravity stimulation. The experiments conducted with this NASA grant fell into two categories. The first area of experimentation was to explore the biochemical interactions between an auxin transport protein and the actin cytoskeleton. These experiments used biochemical techniques, including actin affinity chromatography, to demonstrate that one auxin transport protein interacts with the actin cytoskeleton. The second line of experiments examined whether in the initially symmetrical single celled embryos of Fucus distichus, whether auxin regulates development and whether gravity is a cue to control the morphogenesis of these embryos and whether gravi-morphogenesis is auxin dependent. Results in these two areas are summarized separately below. As a result of this funding, in combination with results from other investigators, we have strong evidence for an important role for the actin cytoskeleton in both establishing and change auxin transport polarity. It is also clear that Fucus distichus embryos are auxin responsive and gravity controls their morphogenesis.

Solitary waves in morphogenesis: Determination fronts as strain-cued strain transformations among automatous cells

NASA Astrophysics Data System (ADS)

Cox, Brian N.; Landis, Chad M.

2018-02-01

We present a simple theory of a strain pulse propagating as a solitary wave through a continuous two-dimensional population of cells. A critical strain is assumed to trigger a strain transformation, while, simultaneously, cells move as automata to tend to restore a preferred cell density. We consider systems in which the strain transformation is a shape change, a burst of proliferation, or the commencement of growth (which changes the shape of the population sheet), and demonstrate isomorphism among these cases. Numerical and analytical solutions describe a strain pulse whose height does not depend on how the strain disturbance was first launched, or the rate at which the strain transformation is achieved, or the rate constant in the rule for the restorative cell motion. The strain pulse is therefore very stable, surviving the imposition of strong perturbations: it would serve well as a timing signal in development. The automatous wave formulation is simple, with few model parameters. A strong case exists for the presence of a strain pulse during amelogenesis. Quantitative analysis reveals a simple relationship between the velocity of the leading edge of the pulse in amelogenesis and the known speed of migration of ameloblast cells. This result and energy arguments support the depiction of wave motion as an automatous cell response to strain, rather than as a response to an elastic energy gradient. The theory may also contribute to understanding the determination front in somitogenesis, moving fronts of convergent-extension transformation, and mitotic wavefronts in the syncytial drosophila embryo.

Candida krusei and Candida glabrata reduce the filamentation of Candida albicans by downregulating expression of HWP1 gene.

PubMed

de Barros, Patrícia Pimentel; Freire, Fernanda; Rossoni, Rodnei Dennis; Junqueira, Juliana Campos; Jorge, Antonio Olavo Cardoso

2017-07-01

Pathogenicity of Candida albicans is associated with its capacity switch from yeast-like to hyphal growth. The hyphal form is capable to penetrate the epithelial surfaces and to damage the host tissues. Therefore, many investigations have focused on mechanisms that control the morphological transitions of C. albicans. Recently, certain studies have showed that non-albicans Candida species can reduce the capacity of C. albicans to form biofilms and to develop candidiasis in animal models. Then, the objective of this study was to evaluate the effects of Candida krusei and Candida glabrata on the morphogenesis of C. albicans. Firstly, the capacity of reference and clinical strains of C. albicans in forming hyphae was tested in vitro. After that, the expression of HWP1 (hyphal wall protein 1) gene was determined by quantitative real-time PCR (polymerase chain reaction) assay. For both reference and clinical strains, a significant inhibition of the hyphae formation was observed when C. albicans was incubated in the presence of C. krusei or C. glabrata compared to the control group composed only by C. albicans. In addition, the culture mixed of C. albicans-C. krusei or C. albicans-C. glabrata reduced significantly the expression of HWP1 gene of C. albicans in relation to single cultures of this specie. In both filamentation and gene expression assays, C. krusei showed the higher inhibitory activity on the morphogenesis of C. albicans compared to C. glabrata. C. krusei and C. glabrata are capable to reduce the filamentation of C. albicans and consequently decrease the expression of the HWP1 gene.

The transcription factor FgStuAp influences spore development, pathogenicity, and secondary metabolism in Fusarium graminearum

USDA-ARS?s Scientific Manuscript database

Members of the APSES family of fungal proteins regulate morphogenesis and virulence in ascomycetes. We deleted the FgStuA gene in Fusarium graminearum and demonstrate its involvement in several different processes. FgStuA is closely related to FoStuA in F. oxysporum and StuA in Aspergillus. Unlike F...

Nrk2b-mediated NAD+ production regulates cell adhesion and is required for muscle morphogenesis in vivo

PubMed Central

Goody, Michelle F.; Kelly, Meghan W.; Lessard, Kevin N.; Khalil, Andre; Henry, Clarissa A.

2010-01-01

Cell-matrix adhesion complexes (CMACs) play fundamental roles during morphogenesis. Given the ubiquitous nature of CMACs and their roles in many cellular processes, one question is how specificity of CMAC function is modulated. The clearly defined cell behaviors that generate segmentally reiterated axial skeletal muscle during zebrafish development comprise an ideal system with which to investigate CMAC function during morphogenesis. We found that Nicotinamide riboside kinase 2b (Nrk2b) cell autonomously modulates the molecular composition of CMACs in vivo. Nrk2b is required for normal Laminin polymerization at the myotendinous junction (MTJ). In Nrk2b-deficient embryos, at MTJ loci where Laminin is not properly polymerized, muscle fibers elongate into adjacent myotomes and are abnormally long. In yeast and human cells, Nrk2 phosphorylates Nicotinamide Riboside and generates NAD+ through an alternative salvage pathway. Exogenous NAD+ treatment rescues MTJ development in Nrk2b-deficient embryos, but not in laminin mutant embryos. Both Nrk2b and Laminin are required for localization of Paxillin, but not β-Dystroglycan, to CMACs at the MTJ. Overexpression of Paxillin in Nrk2b-deficient embryos is sufficient to rescue MTJ integrity. Taken together, these data show that Nrk2b plays a specific role in modulating subcellular localization of discrete CMAC components that in turn play roles in musculoskeletal development. Furthermore, these data suggest that Nrk2b-mediated synthesis of NAD+ is functionally upstream of Laminin adhesion and Paxillin subcellular localization during MTJ development. These results indicate a previously unrecognized complexity to CMAC assembly in vivo and also elucidate a novel role for NAD+ during morphogenesis. PMID:20566368

NFIB regulates embryonic development of submandibular glands.

PubMed

Mellas, R E; Kim, H; Osinski, J; Sadibasic, S; Gronostajski, R M; Cho, M; Baker, O J

2015-02-01

NFIB (nuclear factor I B) is a NFI transcription factor family member, which is essential for the development of a variety of organ systems. Salivary gland development occurs through several stages, including prebud, bud, pseudoglandular, canalicular, and terminal. Although many studies have been done to understand mouse submandibular gland (SMG) branching morphogenesis, little is known about SMG cell differentiation during the terminal stages. The goal of this study was to determine the role of NFIB during SMG development. We analyzed SMGs from wild-type and Nfib-deficient mice (Nfib (-/-)). At embryonic (E) day 18.5, SMGs from wild-type mice showed duct branching morphogenesis and differentiation of tubule ductal cells into tubule secretory cells. In contrast, SMGs from Nfib (-/-) mice at E18.5 failed to differentiate into tubule secretory cells while branching morphogenesis was unaffected. SMGs from wild-type mice at E16.5 displayed well-organized cuboidal inner terminal tubule cells. However, SMGs from Nfib (-/-) at E16.5 displayed disorganized inner terminal tubule cells. SMGs from wild-type mice at E18.5 became fully differentiated, as indicated by a high degree of apicobasal polarization (i.e., presence of apical ZO-1 and basolateral E-cadherin) and columnar shape. Furthermore, SMGs from wild-type mice at E18.5 expressed the protein SMGC, a marker for tubule secretory cells. However, SMGs from Nfib (-/-) mice at E18.5 showed apicobasal polarity, but they were disorganized and lost the ability to secrete SMGC. These findings indicate that the transcription factor NFIB is not required for branching morphogenesis but plays a key role in tubule cell differentiation during mouse SMG development. © International & American Associations for Dental Research 2014.

The Bmp signaling pathway regulates development of left-right asymmetry in amphioxus.

PubMed

Soukup, Vladimir; Kozmik, Zbynek

2018-02-01

Establishment of asymmetry along the left-right (LR) body axis in vertebrates requires interplay between Nodal and Bmp signaling pathways. In the basal chordate amphioxus, the left-sided activity of the Nodal signaling has been attributed to the asymmetric morphogenesis of paraxial structures and pharyngeal organs, however the role of Bmp signaling in LR asymmetry establishment has not been addressed to date. Here, we show that Bmp signaling is necessary for the development of LR asymmetric morphogenesis of amphioxus larvae through regulation of Nodal signaling. Loss of Bmp signaling results in loss of the left-sided expression of Nodal, Gdf1/3, Lefty and Pitx and in gain of ectopic expression of Cerberus on the left side. As a consequence, the larvae display loss of the offset arrangement of axial structures, loss of the left-sided pharyngeal organs including the mouth, and ectopic development of the right-sided organs on the left side. Bmp inhibition thus phenocopies inhibition of Nodal signaling and results in the right isomerism. We conclude that Bmp and Nodal pathways act in concert to specify the left side and that Bmp signaling plays a fundamental role during LR development in amphioxus. Copyright © 2017 Elsevier Inc. All rights reserved.

Geometric control of capillary architecture via cell-matrix mechanical interactions.

PubMed

Sun, Jian; Jamilpour, Nima; Wang, Fei-Yue; Wong, Pak Kin

2014-03-01

Capillary morphogenesis is a multistage, multicellular activity that plays a pivotal role in various developmental and pathological situations. In-depth understanding of the regulatory mechanism along with the capability of controlling the morphogenic process will have direct implications on tissue engineering and therapeutic angiogenesis. Extensive research has been devoted to elucidate the biochemical factors that regulate capillary morphogenesis. The roles of geometric confinement and cell-matrix mechanical interactions on the capillary architecture, nevertheless, remain largely unknown. Here, we show geometric control of endothelial network topology by creating physical confinements with microfabricated fences and wells. Decreasing the thickness of the matrix also results in comparable modulation of the network architecture, supporting the boundary effect is mediated mechanically. The regulatory role of cell-matrix mechanical interaction on the network topology is further supported by alternating the matrix stiffness by a cell-inert PEG-dextran hydrogel. Furthermore, reducing the cell traction force with a Rho-associated protein kinase inhibitor diminishes the boundary effect. Computational biomechanical analysis delineates the relationship between geometric confinement and cell-matrix mechanical interaction. Collectively, these results reveal a mechanoregulation scheme of endothelial cells to regulate the capillary network architecture via cell-matrix mechanical interactions. Copyright © 2014 Elsevier Ltd. All rights reserved.

In vivo imaging of emerging endocrine cells reveals a requirement for PI3K-regulated motility in pancreatic islet morphogenesis

PubMed Central

Freudenblum, Julia; Iglesias, José A.; Hermann, Martin; Walsen, Tanja; Wilfinger, Armin; Meyer, Dirk

2018-01-01

ABSTRACT The three-dimensional architecture of the pancreatic islet is integral to beta cell function, but the process of islet formation remains poorly understood due to the difficulties of imaging internal organs with cellular resolution. Within transparent zebrafish larvae, the developing pancreas is relatively superficial and thus amenable to live imaging approaches. We performed in vivo time-lapse and longitudinal imaging studies to follow islet development, visualizing both naturally occurring islet cells and cells arising with an accelerated timecourse following an induction approach. These studies revealed previously unappreciated fine dynamic protrusions projecting between neighboring and distant endocrine cells. Using pharmacological compound and toxin interference approaches, and single-cell analysis of morphology and cell dynamics, we determined that endocrine cell motility is regulated by phosphoinositide 3-kinase (PI3K) and G-protein-coupled receptor (GPCR) signaling. Linking cell dynamics to islet formation, perturbation of protrusion formation disrupted endocrine cell coalescence, and correlated with decreased islet cell differentiation. These studies identified novel cell behaviors contributing to islet morphogenesis, and suggest a model in which dynamic exploratory filopodia establish cell-cell contacts that subsequently promote cell clustering. PMID:29386244

Spm1, a stress-activated MAP kinase that regulates morphogenesis in S.pombe.

PubMed Central

Zaitsevskaya-Carter, T; Cooper, J A

1997-01-01

A gene encoding a novel MAP kinase family member, Spm1, was isolated from the fission yeast Schizosaccharomyces pombe. Overproduction of Spm1 inhibits proliferation. Disruption of the spm1+ gene interferes with cell separation and morphogenesis. Under conditions of nutrient limitation, hypertonic stress or elevated temperature, spm1 delta cells grow as short branched filaments in which the cell walls and septa are thickened, suggesting defects in polarized growth and cell wall remodeling. At high osmolarity, spm1 delta cells fail to form colonies. The Spm1 protein is tyrosine phosphorylated and activated in response to osmotic and heat stress, consistent with a role for Spm1 in adaptation to these conditions. Two other S.pombe MAP kinases are known, Spk1, required for sexual differentiation and sporulation, and Spc1/Sty1/Phh1, which is activated in hypertonic conditions. However, the distinctive features of the spm1 delta mutant phenotype and direct biochemical assays suggest that Spm1 does not lie on other known MAP kinase pathways. Our results demonstrate the existence of a new MAP kinase pathway that regulates cell wall remodeling and cytokinesis in response to environmental stresses. PMID:9135147

Coordinating cell and tissue behavior during zebrafish neural tube morphogenesis.

PubMed

Araya, Claudio; Ward, Laura C; Girdler, Gemma C; Miranda, Miguel

2016-03-01

The development of a vertebrate neural epithelium with well-organized apico-basal polarity and a central lumen is essential for its proper function. However, how this polarity is established during embryonic development and the potential influence of surrounding signals and tissues on such organization has remained less understood. In recent years the combined superior transparency and genetics of the zebrafish embryo has allowed for in vivo visualization and quantification of the cellular and molecular dynamics that govern neural tube structure. Here, we discuss recent studies revealing how co-ordinated cell-cell interactions coupled with adjacent tissue dynamics are critical to regulate final neural tissue architecture. Furthermore, new findings show how the spatial regulation and timing of orientated cell division is key in defining precise lumen formation at the tissue midline. In addition, we compare zebrafish neurulation with that of amniotes and amphibians in an attempt to understand the conserved cellular mechanisms driving neurulation and resolve the apparent differences among animals. Zebrafish neurulation not only offers fundamental insights into early vertebrate brain development but also the opportunity to explore in vivo cell and tissue dynamics during complex three-dimensional animal morphogenesis. © 2015 Wiley Periodicals, Inc.

Zebrafish bcl2l is a survival factor in thyroid development.

PubMed

Porreca, Immacolata; De Felice, Elena; Fagman, Henrik; Di Lauro, Roberto; Sordino, Paolo

2012-06-15

Regulated cell death, defined in morphological terms as apoptosis, is crucial for organ morphogenesis. While differentiation of the thyroid gland has been extensively studied, nothing is yet known about the survival mechanisms involved in the development of this endocrine gland. Using the zebrafish model system, we aim to understand whether genes belonging to the Bcl-2 family that control apoptosis are implicated in regulation of cell survival during thyroid development. Evidence of strong Bcl-2 gene expression in mouse thyroid precursors prompted us to investigate the functions played by its zebrafish homologs during thyroid development. We show that the bcl2-like (bcl2l) gene is expressed in the zebrafish thyroid primordium. Morpholino-mediated knockdown and mutant analyses revealed that bcl2l is crucial for thyroid cell survival and that this function is tightly modulated by the transcription factors pax2a, nk2.1a and hhex. Also, the bcl2l gene appears to control a caspase-3-dependent apoptotic mechanism during thyroid development. Thyroid precursor cells require an actively maintained survival mechanism to properly proceed through development. The bcl2l gene operates in the inhibition of cell death under direct regulation of a thyroid specific set of transcription factors. This is the first demonstration of an active mechanism to ensure survival of the thyroid primordium during morphogenesis. Copyright © 2012 Elsevier Inc. All rights reserved.

STRIP1, a core component of STRIPAK complexes, is essential for normal mesoderm migration in the mouse embryo.

PubMed

Bazzi, Hisham; Soroka, Ekaterina; Alcorn, Heather L; Anderson, Kathryn V

2017-12-19

Regulated mesoderm migration is necessary for the proper morphogenesis and organ formation during embryonic development. Cell migration and its dependence on the cytoskeleton and signaling machines have been studied extensively in cultured cells; in contrast, remarkably little is known about the mechanisms that regulate mesoderm cell migration in vivo. Here, we report the identification and characterization of a mouse mutation in striatin-interacting protein 1 ( Strip1 ) that disrupts migration of the mesoderm after the gastrulation epithelial-to-mesenchymal transition (EMT). STRIP1 is a core component of the biochemically defined mammalian striatin-interacting phosphatases and kinase (STRIPAK) complexes that appear to act through regulation of protein phosphatase 2A (PP2A), but their functions in mammals in vivo have not been examined. Strip1 -null mutants arrest development at midgestation with profound disruptions in the organization of the mesoderm and its derivatives, including a complete failure of the anterior extension of axial mesoderm. Analysis of cultured mesoderm explants and mouse embryonic fibroblasts from null mutants shows that the mesoderm migration defect is correlated with decreased cell spreading, abnormal focal adhesions, changes in the organization of the actin cytoskeleton, and decreased velocity of cell migration. The results show that STRIPAK complexes are essential for cell migration and tissue morphogenesis in vivo. Copyright © 2017 the Author(s). Published by PNAS.

BMPs and FGFs target Notch signalling via jagged 2 to regulate tooth morphogenesis and cytodifferentiation

PubMed Central

Mitsiadis, Thimios A.; Graf, Daniel; Luder, Hansueli; Gridley, Thomas; Bluteau, Gilles

2010-01-01

The Notch signalling pathway is an evolutionarily conserved intercellular signalling mechanism that is essential for cell fate specification and proper embryonic development. We have analysed the expression, regulation and function of the jagged 2 (Jag2) gene, which encodes a ligand for the Notch family of receptors, in developing mouse teeth. Jag2 is expressed in epithelial cells that give rise to the enamel-producing ameloblasts from the earliest stages of tooth development. Tissue recombination experiments showed that its expression in epithelium is regulated by mesenchyme-derived signals. In dental explants cultured in vitro, the local application of fibroblast growth factors upregulated Jag2 expression, whereas bone morphogenetic proteins provoked the opposite effect. Mice homozygous for a deletion in the Notch-interaction domain of Jag2 presented a variety of severe dental abnormalities. In molars, the crown morphology was misshapen, with additional cusps being formed. This was due to alterations in the enamel knot, an epithelial signalling structure involved in molar crown morphogenesis, in which Bmp4 expression and apoptosis were altered. In incisors, cytodifferentiation and enamel matrix deposition were inhibited. The expression of Tbx1 in ameloblast progenitors, which is a hallmark for ameloblast differentiation and enamel formation, was dramatically reduced in Jag2−/− teeth. Together, these results demonstrate that Notch signalling mediated by Jag2 is indispensable for normal tooth development. PMID:20685737

Dynein-Dependent Transport of nanos RNA in Drosophila Sensory Neurons Requires Rumpelstiltskin and the Germ Plasm Organizer Oskar

PubMed Central

Xu, Xin; Brechbiel, Jillian L.

2013-01-01

Intracellular mRNA localization is a conserved mechanism for spatially regulating protein production in polarized cells, such as neurons. The mRNA encoding the translational repressor Nanos (Nos) forms ribonucleoprotein (RNP) particles that are dendritically localized in Drosophila larval class IV dendritic arborization (da) neurons. In nos mutants, class IV da neurons exhibit reduced dendritic branching complexity, which is rescued by transgenic expression of wild-type nos mRNA but not by a localization-compromised nos derivative. While localization is essential for nos function in dendrite morphogenesis, the mechanism underlying the transport of nos RNP particles was unknown. We investigated the mechanism of dendritic nos mRNA localization by analyzing requirements for nos RNP particle motility in class IV da neuron dendrites through live imaging of fluorescently labeled nos mRNA. We show that dynein motor machinery components mediate transport of nos mRNA in proximal dendrites. Two factors, the RNA-binding protein Rumpelstiltskin and the germ plasm protein Oskar, which are required for diffusion/entrapment-mediated localization of nos during oogenesis, also function in da neurons for formation and transport of nos RNP particles. Additionally, we show that nos regulates neuronal function, most likely independent of its dendritic localization and function in morphogenesis. Our results reveal adaptability of localization factors for regulation of a target transcript in different cellular contexts. PMID:24027279

Dynein-dependent transport of nanos RNA in Drosophila sensory neurons requires Rumpelstiltskin and the germ plasm organizer Oskar.

PubMed

Xu, Xin; Brechbiel, Jillian L; Gavis, Elizabeth R

2013-09-11

Intracellular mRNA localization is a conserved mechanism for spatially regulating protein production in polarized cells, such as neurons. The mRNA encoding the translational repressor Nanos (Nos) forms ribonucleoprotein (RNP) particles that are dendritically localized in Drosophila larval class IV dendritic arborization (da) neurons. In nos mutants, class IV da neurons exhibit reduced dendritic branching complexity, which is rescued by transgenic expression of wild-type nos mRNA but not by a localization-compromised nos derivative. While localization is essential for nos function in dendrite morphogenesis, the mechanism underlying the transport of nos RNP particles was unknown. We investigated the mechanism of dendritic nos mRNA localization by analyzing requirements for nos RNP particle motility in class IV da neuron dendrites through live imaging of fluorescently labeled nos mRNA. We show that dynein motor machinery components mediate transport of nos mRNA in proximal dendrites. Two factors, the RNA-binding protein Rumpelstiltskin and the germ plasm protein Oskar, which are required for diffusion/entrapment-mediated localization of nos during oogenesis, also function in da neurons for formation and transport of nos RNP particles. Additionally, we show that nos regulates neuronal function, most likely independent of its dendritic localization and function in morphogenesis. Our results reveal adaptability of localization factors for regulation of a target transcript in different cellular contexts.

Expression of Iroquois genes is up-regulated during early lung development in the nitrofen-induced pulmonary hypoplasia.

PubMed

Doi, Takashi; Lukošiūtė, Aušra; Ruttenstock, Elke; Dingemann, Jens; Puri, Prem

2011-01-01

Iroquois homeobox (Irx) genes have been implicated in the early lung morphogenesis of vertebrates. Irx1-3 and Irx5 gene expression is seen in fetal lung in rodents up to day (D) 18.5 of gestation. Fetal lung in Irx knockdown mice shows loss of mesenchyme and dilated airspaces, whereas nitrofen-induced hypoplastic lung displays thickened mesenchyme and diminished airspaces. We hypothesized that the Irx genes are up-regulated during early lung morphogenesis in the nitrofen-induced hypoplastic lung. Pregnant rats were exposed either to olive oil or nitrofen on D9. Fetal lungs harvested on D15 were divided into control and nitrofen groups; and the lungs harvested on D18 were divided into control, nitrofen without congenital diaphragmatic hernia (CDH[-]), and nitrofen with CDH (CDH[+]). Irx gene expression levels were analyzed by reverse transcriptase polymerase chain reaction. Immunohistochemistry was performed to evaluate protein expression of Irx family. Pulmonary Irx1-3 and Irx5 messenger RNA expression levels were significantly up-regulated in nitrofen group compared with controls at D15. On D15, Irx immunoreactivity was increased in nitrofen-induced hypoplastic lung compared with controls. Overexpression of Irx genes in the early lung development may cause pulmonary hypoplasia in the nitrofen CDH model by inducing lung dysmorphogenesis with thickened mesenchyme and diminished airspaces. Copyright © 2011 Elsevier Inc. All rights reserved.

Cellular control lies in the balance of forces

NASA Technical Reports Server (NTRS)

Chicurel, M. E.; Chen, C. S.; Ingber, D. E.

1998-01-01

Mechanical tension generated within the cytoskeleton of living cells is emerging as a critical regulator of biological function in diverse situations ranging from the control of chromosome movement to the morphogenesis of the vertebrate brain. In this article, we review recent advances that have been made in terms of understanding how cells generate, transmit and sense mechanical tension, as well as how they use these forces to control their shape and behavior. An integrated view of cell regulation that incorporates mechanics and structure as well as chemistry is beginning to emerge.

Network patterns in exponentially growing two-dimensional biofilms

NASA Astrophysics Data System (ADS)

Zachreson, Cameron; Yap, Xinhui; Gloag, Erin S.; Shimoni, Raz; Whitchurch, Cynthia B.; Toth, Milos

2017-10-01

Anisotropic collective patterns occur frequently in the morphogenesis of two-dimensional biofilms. These patterns are often attributed to growth regulation mechanisms and differentiation based on gradients of diffusing nutrients and signaling molecules. Here, we employ a model of bacterial growth dynamics to show that even in the absence of growth regulation or differentiation, confinement by an enclosing medium such as agar can itself lead to stable pattern formation over time scales that are employed in experiments. The underlying mechanism relies on path formation through physical deformation of the enclosing environment.

Axial protocadherin (AXPC) regulates cell fate during notochordal morphogenesis.

PubMed

Yoder, Michael D; Gumbiner, Barry M

2011-11-01

The separation and specification of mesoderm into the notochord and somites involves members of the non-clustered δ-protocadherins. Axial (AXPC) and paraxial (PAPC) protocadherins are expressed in the early dorsal mesoderm and later become refined to the developing notochordal and somitic mesoderm, respectively. The role of PAPC in this process has been studied extensively, but the role of AXPC is poorly understood. Partial knockdown of AXPC causes a specific bent-axis phenotype, while more severe knockdown results in the loss of notochord formation. The inability of these embryos to develop a notochord is not due to a cell-sorting event via changes in cell adhesion during gastrulation, but rather this defect is manifested through the loss of axial mesoderm specification, but not general mesoderm induction. The results presented here show that AXPC functions in notochord morphogenesis by directing cell-fate decisions rather than cell-cell adhesion. Copyright © 2011 Wiley Periodicals, Inc.

Of smuts, blasts, mildews, and blights: cAMP signaling in phytopathogenic fungi.

PubMed

Lee, Nancy; D'Souza, Cletus A; Kronstad, James W

2003-01-01

cAMP regulates morphogenesis and virulence in a wide variety of fungi including the plant pathogens. In saprophytic yeasts such as Saccharomyces cerevisiae, cAMP signaling plays an important role in nutrient sensing. In filamentous saprophytes, the cAMP pathway appears to play an integral role in vegetative growth and sporulation, with possible connections to mating. Infection-related morphogenesis includes sporulation (conidia and teliospores), formation of appressoria, infection hyphae, and sclerotia. Here, we review studies of cAMP signaling in a variety of plant fungal pathogens. The primary fungi to be considered include Ustilago maydis, Magnaporthe grisea, Cryphonectria parasitica, Colletotrichum and Fusarium species, and Erisyphe graminis. We also include related information on Trichoderma species that act as mycoparasites and biocontrol agents of phytopathogenic fungi. We point out similarities in infection mechanisms, conservation of signaling components, as well as instances of cross-talk with other signaling pathways.

Regulation of Facial Morphogenesis by Endothelin Signaling: Insights from Mice and Fish

PubMed Central

Clouthier, David E.; Garcia, Elvin; Schilling, Thomas F.

2010-01-01

Craniofacial morphogenesis is accomplished through a complex set of developmental events, most of which are initiated in neural crest cells within the pharyngeal arches. Local patterning cues from the surrounding environment induce gene expression within neural crest cells, leading to formation of a diverse set of skeletal elements. Endothelin-1 (Edn1) is one of the primary signals that establish the identities of neural crest cells within the mandibular portion of the first pharyngeal arch. Signaling through its cognate receptor, the endothelin-A receptor, is critical for patterning the ventral/distal portion of the arch (lower jaw) and also participates with Hox genes in patterning more posterior arches. Edn1/Ednra signaling is highly conserved between mouse and zebrafish, and genetic analyses in these two species have provided complementary insights into the patterning cues responsible for establishing the craniofacial complex as well as the genetic basis of facial birth defect syndromes. PMID:20684004

Integration of actomyosin contractility with cell-cell adhesion during dorsal closure.

PubMed

Duque, Julia; Gorfinkiel, Nicole

2016-12-15

In this work, we combine genetic perturbation, time-lapse imaging and quantitative image analysis to investigate how pulsatile actomyosin contractility drives cell oscillations, apical cell contraction and tissue closure during morphogenesis of the amnioserosa, the main force-generating tissue during the dorsal closure in Drosophila We show that Myosin activity determines the oscillatory and contractile behaviour of amnioserosa cells. Reducing Myosin activity prevents cell shape oscillations and reduces cell contractility. By contrast, increasing Myosin activity increases the amplitude of cell shape oscillations and the time cells spend in the contracted phase relative to the expanded phase during an oscillatory cycle, promoting cell contractility and tissue closure. Furthermore, we show that in AS cells, Rok controls Myosin foci formation and Mbs regulates not only Myosin phosphorylation but also adhesion dynamics through control of Moesin phosphorylation, showing that Mbs coordinates actomyosin contractility with cell-cell adhesion during amnioserosa morphogenesis. © 2016. Published by The Company of Biologists Ltd.

Inversin relays Frizzled-8 signals to promote proximal pronephros development

PubMed Central

Lienkamp, Soeren; Ganner, Athina; Boehlke, Christopher; Schmidt, Thorsten; Arnold, Sebastian J.; Schäfer, Tobias; Romaker, Daniel; Schuler, Julia; Hoff, Sylvia; Powelske, Christian; Eifler, Annekathrin; Krönig, Corinna; Bullerkotte, Axel; Nitschke, Roland; Kuehn, E. Wolfgang; Kim, Emily; Burkhardt, Hans; Brox, Thomas; Ronneberger, Olaf; Gloy, Joachim; Walz, Gerd

2010-01-01

Mutations of inversin cause type II nephronophthisis, an infantile autosomal recessive disease characterized by cystic kidney disease and developmental defects. Inversin regulates Wnt signaling and is required for convergent extension movements during early embryogenesis. We now show that Inversin is essential for Xenopus pronephros formation, involving two distinct and opposing forms of cell movements. Knockdown of Inversin abrogated both proximal pronephros extension and distal tubule differentiation, phenotypes similar to that of Xenopus deficient in Frizzled-8. Exogenous Inversin rescued the pronephric defects caused by lack of Frizzled-8, indicating that Inversin acts downstream of Frizzled-8 in pronephros morphogenesis. Depletion of Inversin prevents the recruitment of Dishevelled in response to Frizzled-8 and impeded the accumulation of Dishevelled at the apical membrane of tubular epithelial cells in vivo. Thus, defective tubule morphogenesis seems to contribute to the renal pathology observed in patients with nephronophthisis type II. PMID:21059920

PcFKH1, a novel regulatory factor from the forkhead family, controls the biosynthesis of penicillin in Penicillium chrysogenum.

PubMed

Domínguez-Santos, Rebeca; García-Estrada, Carlos; Kosalková, Katarina; Prieto, Carlos; Santamarta, Irene; Martín, Juan-Francisco

2015-08-01

Penicillin biosynthesis in Penicillium chrysogenum (re-identified as Penicillium rubens) is a good example of a biological process subjected to complex global regulatory networks and serves as a model to study fungal secondary metabolism. The winged-helix family of transcription factors recently described, which includes the forkhead type of proteins, is a key type of regulatory proteins involved in this process. In yeasts and humans, forkhead transcription factors are involved in different processes (cell cycle regulation, cell death control, pre-mRNA processing and morphogenesis); one member of this family of proteins has been identified in the P. chrysogenum genome (Pc18g00430). In this work, we have characterized this novel transcription factor (named PcFKH1) by generating knock-down mutants and overexpression strains. Results clearly indicate that PcFKH1 positively controls antibiotic biosynthesis through the specific interaction with the promoter region of the penDE gene, thus regulating penDE mRNA levels. PcFKH1 also binds to the pcbC promoter, but with low affinity. In addition, it also controls other ancillary genes of the penicillin biosynthetic process, such as phlA (encoding phenylacetyl CoA ligase) and ppt (encoding phosphopantetheinyl transferase). PcFKH1 also plays a role in conidiation and spore pigmentation, but it does not seem to be involved in hyphal morphology or cell division in the improved laboratory reference strain Wisconsin 54-1255. A genome-wide analysis of processes putatively coregulated by PcFKH1 and PcRFX1 (another winged-helix transcription factor) in P. chrysogenum provided evidence of the global effect of these transcription factors in P. chrysogenum metabolism. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

WAVE2 Regulates Epithelial Morphology and Cadherin Isoform Switching through Regulation of Twist and Abl

PubMed Central

Bryce, Nicole S.; Reynolds, Albert B.; Koleske, Anthony J.; Weaver, Alissa M.

2013-01-01

Background Epithelial morphogenesis is a dynamic process that involves coordination of signaling and actin cytoskeletal rearrangements. Principal Findings We analyzed the contribution of the branched actin regulator WAVE2 in the development of 3-dimensional (3D) epithelial structures. WAVE2-knockdown (WAVE2-KD) cells formed large multi-lobular acini that continued to proliferate at an abnormally late stage compared to control acini. Immunostaining of the cell-cell junctions of WAVE2-KD acini revealed weak and heterogeneous E-cadherin staining despite little change in actin filament localization to the same junctions. Analysis of cadherin expression demonstrated a decrease in E-cadherin and an increase in N-cadherin protein and mRNA abundance in total cell lysates. In addition, WAVE2-KD cells exhibited an increase in the mRNA levels of the epithelial-mesenchymal transition (EMT)-associated transcription factor Twist1. KD of Twist1 expression in WAVE2-KD cells reversed the cadherin switching and completely rescued the aberrant 3D morphological phenotype. Activity of the WAVE2 complex binding partner Abl kinase was also increased in WAVE2-KD cells, as assessed by tyrosine phosphorylation of the Abl substrate CrkL. Inhibition of Abl with STI571 rescued the multi-lobular WAVE2-KD 3D phenotype whereas overexpression of Abl kinase phenocopied the WAVE2-KD phenotype. Conclusions The WAVE2 complex regulates breast epithelial morphology by a complex mechanism involving repression of Twist1 expression and Abl kinase activity. These data reveal a critical role for WAVE2 complex in regulation of cellular signaling and epithelial morphogenesis. PMID:23691243

Down-regulation of lung Kruppel-like factor in the nitrofen-induced hypoplastic lung.

PubMed

Lukošiūtė, A; Doi, T; Dingemann, J; Ruttenstock, E M; Puri, P

2011-01-01

Pulmonary hypoplasia is a primary cause of high morbidity and mortality in neonates with Congenital Diaphragmatic Hernia (CDH). However, the precise pathogenesis of PH associated with CDH is still not clearly understood. It has been recently reported that lung Kruppel-like factor (LKLF), a member of the Kruppel-like factor family of transcription factors, is predominantly expressed in lungs and plays an important role in lung morphogenesis and functional maturation. It has been reported that homozygous deletion of LKLF gene in mice results in reduced lung morphogenesis. It is further reported that chimeric mice derived from LKLF (-/-) embryonic stem cells exhibit delayed lung development especially in the later gestational stages. We therefore designed this study to test the hypothesis that the LKLF gene is down-regulated during later stages of lung development in nitrofen-induced hypoplastic lungs. Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). Fetal lungs were harvested on D15, D18, and D21 and divided into 3 groups:control, nitrofen without CDH(CDH(-)) and nitrofen with CDH(CDH(+)) (n=24 for each group). Real-time RT-PCR analysis was performed to investigate pulmonary gene expression levels of LKLF. Differences between the 3 groups at each time point were tested statistically and significance was accepted at p<0.05. Immunohistochemistry was also performed to evaluate LKLF protein expression and distribution. The relative mRNA expression levels of LKLF on D18 and D21 were significantly decreased (p<0.01) in CDH(-) and CDH(+) groups compared to controls. The gene expression levels of LKLF on D15 did not differ significantly between the nitrofen group and controls. Immunohistochemical study showed strong LKLF immunoreactivity on D18 and D21 in nitrofen-induced hypoplastic lung compared to controls, whereas no difference was seen on D15. Our results provide evidence for the first time that LKLF is down-regulated in the later stages of lung development in nitrofen-induced hypoplastic lungs. These data suggest that the down-regulation of LKLF during this critical period of lung morphogenesis may impair lung development and maturation, resulting in pulmonary hypoplasia in the nitrofen CDH model. © Georg Thieme Verlag KG Stuttgart · New York.

Exploiting a Molecular Gleason Grade for Prostate Cancer Therapy

DTIC Science & Technology

2009-03-01

P. (2008) The an- drogen-regulated type II serine protease TMPRSS2 is differentially expressed and mislocal- ized in prostate adenocarcinoma . J...program associated with key points of murine prostate organogenesis spanning the initial in utero induction of prostate budding through maturity. We...studies, we found no significant associations with stages of lung morphogenesis. Genes altered in murine prostate adenocarcinoma map to the branching

Candida species differ in their interactions with immature human gastrointestinal epithelial cells

PubMed Central

Falgier, Christina; Kegley, Sara; Podgorski, Heather; Heisel, Timothy; Storey, Kathleen; Bendel, Catherine M.; Gale, Cheryl A.

2011-01-01

Life-threatening gastrointestinal (GI) diseases of prematurity are highly associated with systemic candidiasis. This implicates the premature GI tract as an important site for invasion by Candida. Invasive interactions of Candida spp. with immature enterocytes have heretofore not been analyzed. Using a primary immature human enterocyte line, we compared the ability of multiple isolates of different Candida spp. to penetrate, injure, and induce a cytokine response from host cells. Of all the Candida spp. analyzed, C. albicans had the greatest ability to penetrate and injure immature enterocytes and to elicit interleukin-8 (IL-8) release (p < 0.01). In addition, C. albicans was the only Candida spp. to form filamentous hyphae when in contact with immature enterocytes. Similarly, a C. albicans mutant with defective hyphal morphogenesis and invasiveness had attenuated cytotoxicity for immature enterocytes (p < 0.003). Thus, hyphal morphogenesis correlates with immature enterocyte penetration, injury and inflammatory responses. Furthermore, variability in enterocyte injury was observed among hyphal-producing C. albicans strains suggesting that individual organism genotypes also influence host-pathogen interactions. Overall, the finding that Candida spp. differed in their interactions with immature enterocytes implicates that individual spp. may employ different pathogenesis mechanisms. PMID:21283049

Ontogeny and Molecular Phylogeny of Apoamphisiella vernalis Reveal Unclear Separation between Genera Apoamphisiella and Paraurostyla (Protozoa, Ciliophora, Hypotricha)

PubMed Central

Fernandes, Noemi Mendes; Schlegel, Martin; Paiva, Thiago da Silva

2016-01-01

Morphology and divisional morphogenesis of the hypotrich ciliate Apoamphisiella vernalis are investigated based on two populations from Brazil. Typical specimens of A. vernalis replicates its ventral ciliature from six fronto-ventral-transverse (FVT) anlagen independently formed for proter and opisthe, plus one or more short anlagen located between IV and V, which form surplus transverse cirri. Dorsal morphogenesis occurs as in typical oxytrichid dorsomarginalians, viz., with formation of three anlagen and fragmentation of the rightmost one. Dorsomarginal kineties are formed near anterior end of right marginal cirral row anlagen. Various anomalous specimens exhibiting more than two long ventral rows were found, which are explained by increasing the number of FVT anlagen and/or the number of cirri produced by anlagen. Comparative ontogeny and phylogenetic analyses based on the 18S rDNA reveal that Apoamphisiella vernalis is closely affine to North American and European strains of the Paraurostyla weissei complex. Their reduced genetic distances and conspicuous morphological variability show that both genera can overlap, which implies the necessity of re-evaluating the contextual relevance of some morphological characters commonly used for genus-level separation within hypotrich taxa. PMID:27196427

Epithelial tricellular junctions act as interphase cell shape sensors to orient mitosis

PubMed Central

Bosveld, Floris; Markova, Olga; Guirao, Boris; Martin, Charlotte; Wang, Zhimin; Pierre, Anaëlle; Balakireva, Maria; Gaugue, Isabelle; Ainslie, Anna; Christophorou, Nicolas; Lubensky, David K.; Minc, Nicolas; Bellaïche, Yohanns

2017-01-01

The orientation of cell division along the interphase cell long-axis, the century old Hertwig’s rule, has profound roles in tissue proliferation, morphogenesis, architecture and mechanics1,2. In epithelial tissues, the shape of the interphase cell is influenced by cell adhesion, mechanical stress, neighbour topology, and planar polarity pathways3–12. At mitosis, epithelial cells usually round up to ensure faithful chromosome segregation and to promote morphogenesis1. The mechanisms underlying interphase cell shape sensing in tissues are therefore unknown. We found that in Drosophila epithelia, tricellular junctions (TCJ) localize microtubule force generators, orienting cell division via the Dynein associated protein Mud independently of the classical Pins/Gαi pathway. Moreover, as cells round up during mitosis, TCJs serve as spatial landmarks, encoding information about interphase cell shape anisotropy to orient division in the rounded mitotic cell. Finally, experimental and simulation data show that shape and mechanical strain sensing by the TCJ emerge from a general geometric property of TCJ distributions in epithelial tissues. Thus, in addition to their function as epithelial barrier structures, TCJs serve as polarity cues promoting geometry and mechanical sensing in epithelial tissues. PMID:26886796

Description and Phylogeny of Urostyla grandis wiackowskii subsp. nov. (Ciliophora, Hypotricha) from an Estuarine Mangrove in Brazil.

PubMed

Paiva, Thiago da Silva; Shao, Chen; Fernandes, Noemi Mendes; Borges, Bárbara do Nascimento; da Silva-Neto, Inácio Domingos

2016-01-01

Interphase specimens, aspects of physiological reorganization and divisional morphogenesis were investigated in a strain of a hypotrichous ciliate highly similar to Urostyla grandis Ehrenberg, (type species of Urostyla), collected from a mangrove area in the estuary of the Paraíba do Sul river (Rio de Janeiro, Brazil). The results revealed that albeit interphase specimens match with the known morphologic variability in U. grandis, morphogenetic processes have conspicuous differences. Parental adoral zone is entirely renewed during morphogenesis, and marginal cirri exhibit a unique combination of developmental modes, in which left marginal rows originate from multiple anlagen arising from innermost left marginal cirral row, whereas right marginal ciliature originates from individual within-row anlagen. Based on such characteristics, a new subspecies, namely U. grandis wiackowskii subsp. nov. is proposed, and consequently, U. grandis grandis Ehrenberg, stat. nov. is established. Bayesian and maximum-likelihood analyses of the 18S rDNA unambiguously placed U. grandis wiackowskii as adelphotaxon of a cluster formed by other U. grandis sequences. The implications of such findings to the systematics of Urostyla are discussed. © 2015 The Author(s) Journal of Eukaryotic Microbiology © 2015 International Society of Protistologists.

Interaction between Two Timing MicroRNAs Controls Trichome Distribution in Arabidopsis

PubMed Central

Xue, Xue-Yi; Zhao, Bo; Chao, Lu-Men; Chen, Dian-Yang; Cui, Wen-Rui; Mao, Ying-Bo; Wang, Ling-Jian; Chen, Xiao-Ya

2014-01-01

The miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) transcription factors function as an endogenous age cue in regulating plant phase transition and phase-dependent morphogenesis, but the control of SPL output remains poorly understood. In Arabidopsis thaliana the spatial pattern of trichome is a hallmark of phase transition and governed by SPLs. Here, by dissecting the regulatory network controlling trichome formation on stem, we show that the miR171-targeted LOST MERISTEMS 1 (LOM1), LOM2 and LOM3, encoding GRAS family members previously known to maintain meristem cell polarity, are involved in regulating the SPL activity. Reduced LOM abundance by overexpression of miR171 led to decreased trichome density on stems and floral organs, and conversely, constitutive expression of the miR171-resistant LOM (rLOM) genes promoted trichome production, indicating that LOMs enhance trichome initiation at reproductive stage. Genetic analysis demonstrated LOMs shaping trichome distribution is dependent on SPLs, which positively regulate trichome repressor genes TRICHOMELESS 1 (TCL1) and TRIPTYCHON (TRY). Physical interaction between the N-terminus of LOMs and SPLs underpins the repression of SPL activity. Importantly, other growth and developmental events, such as flowering, are also modulated by LOM-SPL interaction, indicating a broad effect of the LOM-SPL interplay. Furthermore, we provide evidence that MIR171 gene expression is regulated by its targeted LOMs, forming a homeostatic feedback loop. Our data uncover an antagonistic interplay between the two timing miRNAs in controlling plant growth, phase transition and morphogenesis through direct interaction of their targets. PMID:24699192

Mechanisms of Regulating Tissue Elongation in Drosophila Wing: Impact of Oriented Cell Divisions, Oriented Mechanical Forces, and Reduced Cell Size

PubMed Central

Li, Yingzi; Naveed, Hammad; Kachalo, Sema; Xu, Lisa X.; Liang, Jie

2014-01-01

Regulation of cell growth and cell division plays fundamental roles in tissue morphogenesis. However, the mechanisms of regulating tissue elongation through cell growth and cell division are still not well understood. The wing imaginal disc of Drosophila provides a model system that has been widely used to study tissue morphogenesis. Here we use a recently developed two-dimensional cellular model to study the mechanisms of regulating tissue elongation in Drosophila wing. We simulate the effects of directional cues on tissue elongation. We also computationally analyze the role of reduced cell size. Our simulation results indicate that oriented cell divisions, oriented mechanical forces, and reduced cell size can all mediate tissue elongation, but they function differently. We show that oriented cell divisions and oriented mechanical forces act as directional cues during tissue elongation. Between these two directional cues, oriented mechanical forces have a stronger influence than oriented cell divisions. In addition, we raise the novel hypothesis that reduced cell size may significantly promote tissue elongation. We find that reduced cell size alone cannot drive tissue elongation. However, when combined with directional cues, such as oriented cell divisions or oriented mechanical forces, reduced cell size can significantly enhance tissue elongation in Drosophila wing. Furthermore, our simulation results suggest that reduced cell size has a short-term effect on cell topology by decreasing the frequency of hexagonal cells, which is consistent with experimental observations. Our simulation results suggest that cell divisions without cell growth play essential roles in tissue elongation. PMID:24504016

The activities of the C-terminal regions of the formin protein disheveled-associated activator of morphogenesis (DAAM) in actin dynamics.

PubMed

Vig, Andrea Teréz; Földi, István; Szikora, Szilárd; Migh, Ede; Gombos, Rita; Tóth, Mónika Ágnes; Huber, Tamás; Pintér, Réka; Talián, Gábor Csaba; Mihály, József; Bugyi, Beáta

2017-08-18

Disheveled-associated activator of morphogenesis (DAAM) is a diaphanous-related formin protein essential for the regulation of actin cytoskeleton dynamics in diverse biological processes. The conserved formin homology 1 and 2 (FH1-FH2) domains of DAAM catalyze actin nucleation and processively mediate filament elongation. These activities are indirectly regulated by the N- and C-terminal regions flanking the FH1-FH2 domains. Recently, the C-terminal diaphanous-autoregulatory domain (DAD) and the C terminus (CT) of formins have also been shown to regulate actin assembly by directly interacting with actin. Here, to better understand the biological activities of DAAM, we studied the role of DAD-CT regions of Drosophila DAAM in its interaction with actin with in vitro biochemical and in vivo genetic approaches. We found that the DAD-CT region binds actin in vitro and that its main actin-binding element is the CT region, which does not influence actin dynamics on its own. However, we also found that it can tune the nucleating activity and the filament end-interaction properties of DAAM in an FH2 domain-dependent manner. We also demonstrate that DAD-CT makes the FH2 domain more efficient in antagonizing with capping protein. Consistently, in vivo data suggested that the CT region contributes to DAAM-mediated filopodia formation and dynamics in primary neurons. In conclusion, our results demonstrate that the CT region of DAAM plays an important role in actin assembly regulation in a biological context. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Physics and the canalization of morphogenesis: a grand challenge in organismal biology

PubMed Central

von Dassow, Michelangelo; Davidson, Lance A.

2011-01-01

Morphogenesis takes place in a background of organism-to-organism and environmental variation. Therefore, a fundamental question in the study of morphogenesis is how the mechanical processes of tissue movement and deformation are affected by that variability, and in turn, how the mechanics of the system modulates phenotypic variation. We highlight a few key factors, including environmental temperature, embryo size, and environmental chemistry that might perturb the mechanics of morphogenesis in natural populations. Then we discuss several ways in which mechanics – including feedback from mechanical cues – might influence intra-specific variation in morphogenesis. To understand morphogenesis it will be necessary to consider whole-organism, environment, and evolutionary scales because these larger scales present the challenges that developmental mechanisms have evolved to cope with. Studying the variation organisms express and the variation organisms experience will aid in deciphering the causes of birth defects. PMID:21750364

The Putative C2H2 Transcription Factor MtfA Is a Novel Regulator of Secondary Metabolism and Morphogenesis in Aspergillus nidulans

PubMed Central

Ramamoorthy, Vellaisamy; Dhingra, Sourabh; Kincaid, Alexander; Shantappa, Sourabha; Feng, Xuehuan; Calvo, Ana M.

2013-01-01

Secondary metabolism in the model fungus Aspergillus nidulans is controlled by the conserved global regulator VeA, which also governs morphological differentiation. Among the secondary metabolites regulated by VeA is the mycotoxin sterigmatocystin (ST). The presence of VeA is necessary for the biosynthesis of this carcinogenic compound. We identified a revertant mutant able to synthesize ST intermediates in the absence of VeA. The point mutation occurred at the coding region of a gene encoding a novel putative C2H2 zinc finger domain transcription factor that we denominated mtfA. The A. nidulans mtfA gene product localizes at nuclei independently of the illumination regime. Deletion of the mtfA gene restores mycotoxin biosynthesis in the absence of veA, but drastically reduced mycotoxin production when mtfA gene expression was altered, by deletion or overexpression, in A. nidulans strains with a veA wild-type allele. Our study revealed that mtfA regulates ST production by affecting the expression of the specific ST gene cluster activator aflR. Importantly, mtfA is also a regulator of other secondary metabolism gene clusters, such as genes responsible for the synthesis of terrequinone and penicillin. As in the case of ST, deletion or overexpression of mtfA was also detrimental for the expression of terrequinone genes. Deletion of mtfA also decreased the expression of the genes in the penicillin gene cluster, reducing penicillin production. However, in this case, over-expression of mtfA enhanced the transcription of penicillin genes, increasing penicillin production more than 5 fold with respect to the control. Importantly, in addition to its effect on secondary metabolism, mtfA also affects asexual and sexual development in A. nidulans. Deletion of mtfA results in a reduction of conidiation and sexual stage. We found mtfA putative orthologs conserved in other fungal species. PMID:24066102

Normal morphogenesis of epithelial tissues and progression of epithelial tumors

PubMed Central

Wang, Chun-Chao; Jamal, Leen; Janes, Kevin A.

2011-01-01

Epithelial cells organize into various tissue architectures that largely maintain their structure throughout the life of an organism. For decades, the morphogenesis of epithelial tissues has fascinated scientists at the interface of cell, developmental, and molecular biology. Systems biology offers ways to combine knowledge from these disciplines by building integrative models that are quantitative and predictive. Can such models be useful for gaining a deeper understanding of epithelial morphogenesis? Here, we take inventory of some recurring themes in epithelial morphogenesis that systems approaches could strive to capture. Predictive understanding of morphogenesis at the systems level would prove especially valuable for diseases such as cancer, where epithelial tissue architecture is profoundly disrupted. PMID:21898857

A Rapid CRISPR/Cas-based Mutagenesis Assay in Zebrafish for Identification of Genes Involved in Thyroid Morphogenesis and Function.

PubMed

Trubiroha, A; Gillotay, P; Giusti, N; Gacquer, D; Libert, F; Lefort, A; Haerlingen, B; De Deken, X; Opitz, R; Costagliola, S

2018-04-04

The foregut endoderm gives rise to several organs including liver, pancreas, lung and thyroid with important roles in human physiology. Understanding which genes and signalling pathways regulate their development is crucial for understanding developmental disorders as well as diseases in adulthood. We exploited unique advantages of the zebrafish model to develop a rapid and scalable CRISPR/Cas-based mutagenesis strategy aiming at the identification of genes involved in morphogenesis and function of the thyroid. Core elements of the mutagenesis assay comprise bi-allelic gene invalidation in somatic mutants, a non-invasive monitoring of thyroid development in live transgenic fish, complementary analyses of thyroid function in fixed specimens and quantitative analyses of mutagenesis efficiency by Illumina sequencing of individual fish. We successfully validated our mutagenesis-phenotyping strategy in experiments targeting genes with known functions in early thyroid morphogenesis (pax2a, nkx2.4b) and thyroid functional differentiation (duox, duoxa, tshr). We also demonstrate that duox and duoxa crispants phenocopy thyroid phenotypes previously observed in human patients with bi-allelic DUOX2 and DUOXA2 mutations. The proposed combination of efficient mutagenesis protocols, rapid non-invasive phenotyping and sensitive genotyping holds great potential to systematically characterize the function of larger candidate gene panels during thyroid development and is applicable to other organs and tissues.

Endoderm-specific deletion of Tbx1 reveals an FGF-independent role for Tbx1 in pharyngeal apparatus morphogenesis

PubMed Central

Jackson, Abigail; Kasah, Sahrunizam; Mansour, Suzanne L.; Morrow, Bernice; Basson, M. Albert

2015-01-01

Background The T-box transcription factor Tbx1, is essential for the normal development of multiple organ systems in the embryo. One of the most striking phenotypes in Tbx1−/− embryos is the failure of the caudal pharyngeal pouches to evaginate from the foregut endoderm. Despite considerable interest in the role of Tbx1 in development, the mechanisms whereby Tbx1 controls caudal pouch formation have remained elusive. In particular, the question as to how Tbx1 expression in the pharyngeal endoderm regulates pharyngeal pouch morphogenesis in the mouse embryo is not known. Results To address this question, we produced mouse embryos in which Tbx1 was specifically deleted from the pharyngeal endoderm and as expected, embryos failed to form caudal pharyngeal pouches. To determine the molecular mechanism, we examined expression of Fgf3 and Fgf8 ligands and downstream effectors. Although Fgf8 expression is greatly reduced in Tbx1-deficient endoderm, FGF signaling levels are unaffected. Furthermore, pouch morphogenesis is only partially perturbed by the loss of both Fgf3 and Fgf8 from the endoderm, indicating that neither are required for pouch formation. Conclusions Tbx1 deletion from the pharyngeal endoderm is sufficient to cause caudal pharyngeal arch segmentation defects by FGF-independent effectors that remain to be identified. PMID:24812002

The cell shape proteins MreB and MreC control cell morphogenesis by positioning cell wall synthetic complexes.

PubMed

Divakaruni, Arun V; Baida, Cyril; White, Courtney L; Gober, James W

2007-10-01

MreB, the bacterial actin homologue, is thought to function in spatially co-ordinating cell morphogenesis in conjunction with MreC, a protein that wraps around the outside of the cell within the periplasmic space. In Caulobacter crescentus, MreC physically associates with penicillin-binding proteins (PBPs) which catalyse the insertion of intracellularly synthesized precursors into the peptidoglycan cell wall. Here we show that MreC is required for the spatial organization of components of the peptidoglycan-synthesizing holoenzyme in the periplasm and MreB directs the localization of a peptidoglycan precursor synthesis protein in the cytosol. Additionally, fluorescent vancomycin (Van-FL) labelling revealed that the bacterial cytoskeletal proteins MreB and FtsZ, as well as MreC and RodA, were required for peptidoglycan synthetic activity. MreB and FtsZ were found to be required for morphogenesis of the polar stalk. FtsZ was required for a cell cycle-regulated burst of peptidoglycan synthesis early in the cell cycle resulting in the synthesis of cross-band structures, whereas MreB was required for lengthening of the stalk. Thus, the bacterial cytoskeleton and cell shape-determining proteins such as MreC, function in concert to orchestrate the localization of cell wall synthetic complexes resulting in spatially co-ordinated and efficient peptidoglycan synthetic activity.

A Secreted Peptide and Its Receptors Shape the Auxin Response Pattern and Leaf Margin Morphogenesis.

PubMed

Tameshige, Toshiaki; Okamoto, Satoshi; Lee, Jin Suk; Aida, Mitsuhiro; Tasaka, Masao; Torii, Keiko U; Uchida, Naoyuki

2016-09-26

Secreted peptides mediate intercellular communication [1, 2]. Several secreted peptides in the EPIDERMAL PATTERNING FACTOR-LIKE (EPFL) family regulate morphogenesis of tissues, such as stomata and inflorescences in plants [3-15]. The biological functions of other EPFL family members remain unknown. Here, we show that the EPFL2 gene is required for growth of leaf teeth. EPFL2 peptide physically interacts with ERECTA (ER) family receptor-kinases and, accordingly, the attenuation of ER family activities leads to formation of toothless leaves. During the tooth growth process, responses to the phytohormone auxin are maintained at tips of the teeth to promote their growth [16-19]. In the growing tooth tip of epfl2 and multiple er family mutants, the auxin response becomes broader. Conversely, overexpression of EPFL2 diminishes the auxin response, indicating that the EPFL2 signal restricts the auxin response to the tooth tip. Interestingly, the tip-specific auxin response in turn organizes characteristic expression patterns of ER family and EPFL2 by enhancing ER family expression at the tip while eliminating the EPFL2 expression from the tip. Our findings identify the novel ligand-receptor pairs promoting the tooth growth, and further reveal a feedback circuit between the peptide-receptor system and auxin response as a mechanism for maintaining proper auxin maxima during leaf margin morphogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Feedback control of growth, differentiation, and morphogenesis of pancreatic endocrine progenitors in an epithelial plexus niche

PubMed Central

Bankaitis, Eric D.; Bechard, Matthew E.; Wright, Christopher V.E.

2015-01-01

In the mammalian pancreas, endocrine cells undergo lineage allocation upon emergence from a bipotent duct/endocrine progenitor pool, which resides in the “trunk epithelium.” Major questions remain regarding how niche environments are organized within this epithelium to coordinate endocrine differentiation with programs of epithelial growth, maturation, and morphogenesis. We used EdU pulse-chase and tissue-reconstruction approaches to analyze how endocrine progenitors and their differentiating progeny are assembled within the trunk as it undergoes remodeling from an irregular plexus of tubules to form the eventual mature, branched ductal arbor. The bulk of endocrine progenitors is maintained in an epithelial “plexus state,” which is a transient intermediate during epithelial maturation within which endocrine cell differentiation is continually robust and surprisingly long-lived. Within the plexus, local feedback effects derived from the differentiating and delaminating endocrine cells nonautonomously regulate the flux of endocrine cell birth as well as proliferative growth of the bipotent cell population using Notch-dependent and Notch-independent influences, respectively. These feedback effects in turn maintain the plexus state to ensure prolonged allocation of endocrine cells late into gestation. These findings begin to define a niche-like environment guiding the genesis of the endocrine pancreas and advance current models for how differentiation is coordinated with the growth and morphogenesis of the developing pancreatic epithelium. PMID:26494792

Ott1 (Rbm15) is essential for placental vascular branching morphogenesis and embryonic development of the heart and spleen.

PubMed

Raffel, Glen D; Chu, Gerald C; Jesneck, Jonathan L; Cullen, Dana E; Bronson, Roderick T; Bernard, Olivier A; Gilliland, D Gary

2009-01-01

The infant leukemia-associated gene Ott1 (Rbm15) has broad regulatory effects within murine hematopoiesis. However, germ line Ott1 deletion results in fetal demise prior to embryonic day 10.5, indicating additional developmental requirements for Ott1. The spen gene family, to which Ott1 belongs, has a transcriptional activation/repression domain and RNA recognition motifs and has a significant role in the development of the head and thorax in Drosophila melanogaster. Early Ott1-deficient embryos show growth retardation and incomplete closure of the notochord. Further analysis demonstrated placental defects in the spongiotrophoblast and syncytiotrophoblast layers, resulting in an arrest of vascular branching morphogenesis. The rescue of the placental defect using a conditional allele with a trophoblast-sparing cre transgene allowed embryos to form a normal placenta and survive gestation. This outcome showed that the process of vascular branching morphogenesis in Ott1-deficient animals was regulated by the trophoblast compartment rather than the fetal vasculature. Mice surviving to term manifested hyposplenia and abnormal cardiac development. Analysis of global gene expression of Ott1-deficient embryonic hearts showed an enrichment of hypoxia-related genes and a significant alteration of several candidate genes critical for cardiac development. Thus, Ott1-dependent pathways, in addition to being implicated in leukemogenesis, may also be important for the pathogenesis of placental insufficiency and cardiac malformations.

The ADAMTS5 Metzincin Regulates Zebrafish Somite Differentiation

PubMed Central

Dancevic, Carolyn M.; Gibert, Yann; Smith, Adam D.; Ward, Alister C.; McCulloch, Daniel R.

2018-01-01

The ADAMTS5 metzincin, a secreted zinc-dependent metalloproteinase, modulates the extracellular matrix (ECM) during limb morphogenesis and other developmental processes. Here, the role of ADAMTS5 was investigated by knockdown of zebrafish adamts5 during embryogenesis. This revealed impaired Sonic Hedgehog (Shh) signaling during somite patterning and early myogenesis. Notably, synergistic regulation of myod expression by ADAMTS5 and Shh during somite differentiation was observed. These roles were not dependent upon the catalytic activity of ADAMTS5. These data identify a non-enzymatic function for ADAMTS5 in regulating an important cell signaling pathway that impacts on muscle development, with implications for musculoskeletal diseases in which ADAMTS5 and Shh have been associated. PMID:29518972

Functional Analysis of the Aspergillus nidulans Kinome

PubMed Central

De Souza, Colin P.; Hashmi, Shahr B.; Osmani, Aysha H.; Andrews, Peter; Ringelberg, Carol S.; Dunlap, Jay C.; Osmani, Stephen A.

2013-01-01

The filamentous fungi are an ecologically important group of organisms which also have important industrial applications but devastating effects as pathogens and agents of food spoilage. Protein kinases have been implicated in the regulation of virtually all biological processes but how they regulate filamentous fungal specific processes is not understood. The filamentous fungus Aspergillus nidulans has long been utilized as a powerful molecular genetic system and recent technical advances have made systematic approaches to study large gene sets possible. To enhance A. nidulans functional genomics we have created gene deletion constructs for 9851 genes representing 93.3% of the encoding genome. To illustrate the utility of these constructs, and advance the understanding of fungal kinases, we have systematically generated deletion strains for 128 A. nidulans kinases including expanded groups of 15 histidine kinases, 7 SRPK (serine-arginine protein kinases) kinases and an interesting group of 11 filamentous fungal specific kinases. We defined the terminal phenotype of 23 of the 25 essential kinases by heterokaryon rescue and identified phenotypes for 43 of the 103 non-essential kinases. Uncovered phenotypes ranged from almost no growth for a small number of essential kinases implicated in processes such as ribosomal biosynthesis, to conditional defects in response to cellular stresses. The data provide experimental evidence that previously uncharacterized kinases function in the septation initiation network, the cell wall integrity and the morphogenesis Orb6 kinase signaling pathways, as well as in pathways regulating vesicular trafficking, sexual development and secondary metabolism. Finally, we identify ChkC as a third effector kinase functioning in the cellular response to genotoxic stress. The identification of many previously unknown functions for kinases through the functional analysis of the A. nidulans kinome illustrates the utility of the A. nidulans gene deletion constructs. PMID:23505451

The Dictyostelium MAP kinase kinase DdMEK1 regulates chemotaxis and is essential for chemoattractant-mediated activation of guanylyl cyclase.

PubMed Central

Ma, H; Gamper, M; Parent, C; Firtel, R A

1997-01-01

We have identified a MAP kinase kinase (DdMEK1) that is required for proper aggregation in Dictyostelium. Null mutations produce extremely small aggregate sizes, resulting in the formation of slugs and terminal fruiting bodies that are significantly smaller than those of wild-type cells. Time-lapse video microscopy and in vitro assays indicate that the cells are able to produce cAMP waves that move through the aggregation domains. However, these cells are unable to undergo chemotaxis properly during aggregation in response to the chemoattractant cAMP or activate guanylyl cyclase, a known regulator of chemotaxis in Dictyostelium. The activation of guanylyl cyclase in response to osmotic stress is, however, normal. Expression of putative constitutively active forms of DdMEK1 in a ddmek1 null background is capable, at least partially, of complementing the small aggregate size defect and the ability to activate guanylyl cyclase. However, this does not result in constitutive activation of guanylyl cyclase, suggesting that DdMEK1 activity is necessary, but not sufficient, for cAMP activation of guanylyl cyclase. Analysis of a temperature-sensitive DdMEK1 mutant suggests that DdMEK1 activity is required throughout aggregation at the time of guanylyl cyclase activation, but is not essential for proper morphogenesis during the later multicellular stages. The activation of the MAP kinase ERK2, which is essential for chemoattractant activation of adenylyl cyclase, is not affected in ddmek1 null strains, indicating that DdMEK1 does not regulate ERK2 and suggesting that at least two independent MAP kinase cascades control aggregation in Dictyostelium. PMID:9250676

Fatty Acid Oxidation Is Required for Myxococcus xanthus Development.

PubMed

Bullock, Hannah A; Shen, Huifeng; Boynton, Tye O; Shimkets, Lawrence J

2018-05-15

Myxococcus xanthus cells produce lipid bodies containing triacylglycerides during fruiting body development. Fatty acid β-oxidation is the most energy-efficient pathway for lipid body catabolism. In this study, we used mutants in fadJ (MXAN_5371 and MXAN_6987) and fadI (MXAN_5372) homologs to examine whether β-oxidation serves an essential developmental function. These mutants contained more lipid bodies than the wild-type strain DK1622 and 2-fold more flavin adenine dinucleotide (FAD), consistent with the reduced consumption of fatty acids by β-oxidation. The β-oxidation pathway mutants exhibited differences in fruiting body morphogenesis and produced spores with thinner coats and a greater susceptibility to thermal stress and UV radiation. The MXAN_5372/5371 operon is upregulated in sporulating cells, and its expression could not be detected in csgA , fruA , or mrpC mutants. Lipid bodies were found to persist in mature spores of DK1622 and wild strain DK851, suggesting that the roles of lipid bodies and β-oxidation may extend to spore germination. IMPORTANCE Lipid bodies act as a reserve of triacylglycerides for use when other sources of carbon and energy become scarce. β-Oxidation is essential for the efficient metabolism of fatty acids associated with triacylglycerides. Indeed, the disruption of genes in this pathway has been associated with severe disorders in animals and plants. Myxococcus xanthus , a model organism for the study of development, is ideal for investigating the complex effects of altered lipid metabolism on cell physiology. Here, we show that β-oxidation is used to consume fatty acids associated with lipid bodies and that the disruption of the β-oxidation pathway is detrimental to multicellular morphogenesis and spore formation. Copyright © 2018 American Society for Microbiology.

TGF-β Family Signaling in Embryonic and Somatic Stem Cell Renewal and Differentiation

PubMed Central

Mullen, Alan C.; Wrana, Jeffrey L.

2017-01-01

Soon after the discovery of Transforming Growth Factor-beta (TGF-β), seminal work in vertebrate and invertebrate models revealed the TGF-β family to be central regulators of tissue morphogenesis. Members of the family direct some of the earliest cell fate decisions in animal development, coordinate complex organogenesis and contribute to tissue homeostasis in the adult. Here we focus on the role of the TGF-β family in mammalian stem cell biology and discuss its wide and varied activities both in the regulation of pluripotency and in cell fate commitment. PMID:28108485

Laminin and Matrix metalloproteinase 11 regulate Fibronectin levels in the zebrafish myotendinous junction.

PubMed

Jenkins, Molly H; Alrowaished, Sarah S; Goody, Michelle F; Crawford, Bryan D; Henry, Clarissa A

2016-01-01

Remodeling of the extracellular matrix (ECM) regulates cell adhesion as well as signaling between cells and their microenvironment. Despite the importance of tightly regulated ECM remodeling for normal muscle development and function, mechanisms underlying ECM remodeling in vivo remain elusive. One excellent paradigm in which to study ECM remodeling in vivo is morphogenesis of the myotendinous junction (MTJ) during zebrafish skeletal muscle development. During MTJ development, there are dramatic shifts in the primary components comprising the MTJ matrix. One such shift involves the replacement of Fibronectin (Fn)-rich matrix, which is essential for both somite and early muscle development, with laminin-rich matrix essential for normal function of the myotome. Here, we investigate the mechanism underlying this transition. We show that laminin polymerization indirectly promotes Fn downregulation at the MTJ, via a matrix metalloproteinase 11 (Mmp11)-dependent mechanism. Laminin deposition and organization is required for localization of Mmp11 to the MTJ, where Mmp11 is both necessary and sufficient for Fn downregulation in vivo. Furthermore, reduction of residual Mmp11 in laminin mutants promotes a Fn-rich MTJ that partially rescues skeletal muscle architecture. These results identify a mechanism for Fn downregulation at the MTJ, highlight crosstalk between laminin and Fn, and identify a new in vivo function for Mmp11. Taken together, our data demonstrate a novel signaling pathway mediating Fn downregulation. Our data revealing new regulatory mechanisms that guide ECM remodeling during morphogenesis in vivo may inform pathological conditions in which Fn is dysregulated.

EGFR signaling regulates cell proliferation, differentiation and morphogenesis during planarian regeneration and homeostasis.

PubMed

Fraguas, Susanna; Barberán, Sara; Cebrià, Francesc

2011-06-01

Similarly to development, the process of regeneration requires that cells accurately sense and respond to their external environment. Thus, intrinsic cues must be integrated with signals from the surrounding environment to ensure appropriate temporal and spatial regulation of tissue regeneration. Identifying the signaling pathways that control these events will not only provide insights into a fascinating biological phenomenon but may also yield new molecular targets for use in regenerative medicine. Among classical models to study regeneration, freshwater planarians represent an attractive system in which to investigate the signals that regulate cell proliferation and differentiation, as well as the proper patterning of the structures being regenerated. Recent studies in planarians have begun to define the role of conserved signaling pathways during regeneration. Here, we extend these analyses to the epidermal growth factor (EGF) receptor pathway. We report the characterization of three epidermal growth factor (EGF) receptors in the planarian Schmidtea mediterranea. Silencing of these genes by RNA interference (RNAi) yielded multiple defects in intact and regenerating planarians. Smed-egfr-1(RNAi) resulted in decreased differentiation of eye pigment cells, abnormal pharynx regeneration and maintenance, and the development of dorsal outgrowths. In contrast, Smed-egfr-3(RNAi) animals produced smaller blastemas associated with abnormal differentiation of certain cell types. Our results suggest important roles for the EGFR signaling in controlling cell proliferation, differentiation and morphogenesis during planarian regeneration and homeostasis. Copyright © 2011 Elsevier Inc. All rights reserved.

Nonmuscle Myosin II Regulates the Morphogenesis of Metanephric Mesenchyme–Derived Immature Nephrons

PubMed Central

Recuenco, Mariam C.; Ohmori, Tomoko; Tanigawa, Shunsuke; Taguchi, Atsuhiro; Fujimura, Sayoko; Conti, Mary Anne; Wei, Qize; Kiyonari, Hiroshi; Abe, Takaya; Adelstein, Robert S.

2015-01-01

The kidney develops from reciprocal interactions between the metanephric mesenchyme and ureteric bud. The mesenchyme transforms into epithelia and forms complicated nephron structures, whereas the ureteric bud extends its pre-existing epithelial ducts. Although the roles are well established for extracellular stimuli, such as Wnt and Notch, it is unclear how the intracellular cytoskeleton regulates these morphogenetic processes. Myh9 and Myh10 encode nonmuscle myosin II heavy chains, and Myh9 mutations in humans are implicated in congenital kidney diseases and focal segmental glomerulosclerosis in adults. Here, we analyzed the roles of Myh9 and Myh10 in the developing kidney. Ureteric bud-specific depletion of Myh9 resulted in no apparent phenotypes, whereas mesenchyme-specific Myh9 deletion caused proximal tubule dilations and renal failure. Mesenchyme-specific Myh9/Myh10 mutant mice died shortly after birth and showed a severe defect in nephron formation. The nascent mutant nephrons failed to form a continuous lumen, which likely resulted from impaired apical constriction of the elongating tubules. In addition, nephron progenitors lacking Myh9/Myh10 or the possible interactor Kif26b were less condensed at midgestation and reduced at birth. Taken together, nonmuscle myosin II regulates the morphogenesis of immature nephrons derived from the metanephric mesenchyme and the maintenance of nephron progenitors. Our data also suggest that Myh9 deletion in mice results in failure to maintain renal tubules but not in glomerulosclerosis. PMID:25168025

Cftr controls lumen expansion and function of Kupffer’s vesicle in zebrafish

PubMed Central

Navis, Adam; Marjoram, Lindsay; Bagnat, Michel

2013-01-01

Regulated fluid secretion is crucial for the function of most organs. In vertebrates, the chloride channel cystic fibrosis transmembrane conductance regulator (CFTR) is a master regulator of fluid secretion. Although the biophysical properties of CFTR have been well characterized in vitro, little is known about its in vivo role during development. Here, we investigated the function of Cftr during zebrafish development by generating several cftr mutant alleles using TAL effector nucleases. We found that loss of cftr function leads to organ laterality defects. In zebrafish, left-right (LR) asymmetry requires cilia-driven fluid flow within the lumen of Kupffer’s vesicle (KV). Using live imaging we found that KV morphogenesis is disrupted in cftr mutants. Loss of Cftr-mediated fluid secretion impairs KV lumen expansion leading to defects in organ laterality. Using bacterial artificial chromosome recombineering, we generated transgenic fish expressing functional Cftr fusion proteins with fluorescent tags under the control of the cftr promoter. The transgenes completely rescued the cftr mutant phenotype. Live imaging of these transgenic lines showed that Cftr is localized to the apical membrane of the epithelial cells in KV during lumen formation. Pharmacological stimulation of Cftr-dependent fluid secretion led to an expansion of the KV lumen. Conversely, inhibition of ion gradient formation impaired KV lumen inflation. Interestingly, cilia formation and motility in KV were not affected, suggesting that fluid secretion and flow are independently controlled in KV. These findings uncover a new role for cftr in KV morphogenesis and function during zebrafish development. PMID:23487313

Differentially-dimensioned furrow formation by zygotic gene expression and the MBT

PubMed Central

Xie, Yi

2018-01-01

Despite extensive work on the mechanisms that generate plasma membrane furrows, understanding how cells are able to dynamically regulate furrow dimensions is an unresolved question. Here, we present an in-depth characterization of furrow behaviors and their regulation in vivo during early Drosophila morphogenesis. We show that the deepening in furrow dimensions with successive nuclear cycles is largely due to the introduction of a new, rapid ingression phase (Ingression II). Blocking the midblastula transition (MBT) by suppressing zygotic transcription through pharmacological or genetic means causes the absence of Ingression II, and consequently reduces furrow dimensions. The analysis of compound chromosomes that produce chromosomal aneuploidies suggests that multiple loci on the X, II, and III chromosomes contribute to the production of differentially-dimensioned furrows, and we track the X-chromosomal contribution to furrow lengthening to the nullo gene product. We further show that checkpoint proteins are required for furrow lengthening; however, mitotic phases of the cell cycle are not strictly deterministic for furrow dimensions, as a decoupling of mitotic phases with periods of active ingression occurs as syncytial furrow cycles progress. Finally, we examined the turnover of maternal gene products and find that this is a minor contributor to the developmental regulation of furrow morphologies. Our results suggest that cellularization dynamics during cycle 14 are a continuation of dynamics established during the syncytial cycles and provide a more nuanced view of developmental- and MBT-driven morphogenesis. PMID:29337989

Exogenous Cellulase Switches Cell Interdigitation to Cell Elongation in an RIC1-dependent Manner in Arabidopsis thaliana Cotyledon Pavement Cells.

PubMed

Higaki, Takumi; Takigawa-Imamura, Hisako; Akita, Kae; Kutsuna, Natsumaro; Kobayashi, Ryo; Hasezawa, Seiichiro; Miura, Takashi

2017-01-01

Pavement cells in cotyledons and true leaves exhibit a jigsaw puzzle-like morphology in most dicotyledonous plants. Among the molecular mechanisms mediating cell morphogenesis, two antagonistic Rho-like GTPases regulate local cell outgrowth via cytoskeletal rearrangements. Analyses of several cell wall-related mutants suggest the importance of cell wall mechanics in the formation of interdigitated patterns. However, how these factors are integrated is unknown. In this study, we observed that the application of exogenous cellulase to hydroponically grown Arabidopsis thaliana cotyledons switched the interdigitation of pavement cells to the production of smoothly elongated cells. The cellulase-induced inhibition of cell interdigitation was not observed in a RIC1 knockout mutant. This gene encodes a Rho-like GTPase-interacting protein important for localized cell growth suppression via microtubule bundling on concave cell interfaces. Additionally, to characterize pavement cell morphologies, we developed a mathematical model that considers the balance between cell and cell wall growth, restricted global cell growth orientation, and regulation of local cell outgrowth mediated by a Rho-like GTPase-cytoskeleton system. Our computational simulations fully support our experimental observations, and suggest that interdigitated patterns form because of mechanical buckling in the absence of Rho-like GTPase-dependent regulation of local cell outgrowth. Our model clarifies the cell wall mechanics influencing pavement cell morphogenesis. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Plakophilin-1, a Novel Wnt Signaling Regulator, Is Critical for Tooth Development and Ameloblast Differentiation

PubMed Central

Arai, Chieko; Yamada, Aya; Saito, Kan; Ishikawa, Masaki; Xue, Han; Funada, Keita; Haruyama, Naoto; Yamada, Yoshihiko; Fukumoto, Satoshi; Takahashi, Ichiro

2016-01-01

Tooth morphogenesis is initiated by reciprocal interactions between the ectoderm and neural crest-derived mesenchyme, and the Wnt signaling pathway is involved in this process. We found that Plakophilin (PKP)1, which is associated with diseases such as ectodermal dysplasia/skin fragility syndrome, was highly expressed in teeth and skin, and was upregulated during tooth development. We hypothesized that PKP1 regulates Wnt signaling via its armadillo repeat domain in a manner similar to β-catenin. To determine its role in tooth development, we performed Pkp1 knockdown experiments using ex vivo organ cultures and cell cultures. Loss of Pkp1 reduced the size of tooth germs and inhibited dental epithelial cell proliferation, which was stimulated by Wnt3a. Furthermore, transfected PKP1-emerald green fluorescent protein was translocated from the plasma membrane to the nucleus upon stimulation with Wnt3a and LiCl, which required the PKP1 N terminus (amino acids 161 to 270). Localization of PKP1, which is known as an adhesion-related desmosome component, shifted to the plasma membrane during ameloblast differentiation. In addition, Pkp1 knockdown disrupted the localization of Zona occludens 1 in tight junctions and inhibited ameloblast differentiation; the two proteins were shown to directly interact by immunoprecipitation. These results implicate the participation of PKP1 in early tooth morphogenesis as an effector of canonical Wnt signaling that controls ameloblast differentiation via regulation of the cell adhesion complex. PMID:27015268

Ecdysone signaling induces two phases of cell cycle exit in Drosophila cells

PubMed Central

Guo, Yongfeng; Flegel, Kerry; Kumar, Jayashree; McKay, Daniel J.

2016-01-01

ABSTRACT During development, cell proliferation and differentiation must be tightly coordinated to ensure proper tissue morphogenesis. Because steroid hormones are central regulators of developmental timing, understanding the links between steroid hormone signaling and cell proliferation is crucial to understanding the molecular basis of morphogenesis. Here we examined the mechanism by which the steroid hormone ecdysone regulates the cell cycle in Drosophila. We find that a cell cycle arrest induced by ecdysone in Drosophila cell culture is analogous to a G2 cell cycle arrest observed in the early pupa wing. We show that in the wing, ecdysone signaling at the larva-to-puparium transition induces Broad which in turn represses the cdc25c phosphatase String. The repression of String generates a temporary G2 arrest that synchronizes the cell cycle in the wing epithelium during early pupa wing elongation and flattening. As ecdysone levels decline after the larva-to-puparium pulse during early metamorphosis, Broad expression plummets, allowing String to become re-activated, which promotes rapid G2/M progression and a subsequent synchronized final cell cycle in the wing. In this manner, pulses of ecdysone can both synchronize the final cell cycle and promote the coordinated acquisition of terminal differentiation characteristics in the wing. PMID:27737823

Inactivation of the Catalytic Subunit of cAMP-Dependent Protein Kinase A Causes Delayed Appressorium Formation and Reduced Pathogenicity of Colletotrichum gloeosporioides

PubMed Central

Priyatno, Tri Puji; Abu Bakar, Farah Diba; Kamaruddin, Nurhaida; Mahadi, Nor Muhammad; Abdul Murad, Abdul Munir

2012-01-01

The cyclic AMP- (cAMP-) dependent protein kinase A signaling pathway is one of the major signaling pathways responsible for regulation of the morphogenesis and pathogenesis of several pathogenic fungi. To evaluate the role of this pathway in the plant pathogenic fungus, Colletotrichum gloeosporioides, the gene encoding the catalytic subunit of cAMP-dependent protein kinase A, CgPKAC, was cloned, inactivated, and the mutant was analyzed. Analysis of the Cgpkac mutant generated via gene replacement showed that the mutants were able to form appressoria; however, their formation was delayed compared to the wild type. In addition, the mutant conidia underwent bipolar germination after appressoria formation, but no appressoria were generated from the second germ tube. The mutants also showed reduced ability to adhere to a hydrophobic surface and to degrade lipids localized in the appressoria. Based on the number of lesions produced during a pathogenicity test, the mutant's ability to cause disease in healthy mango fruits was reduced, which may be due to failure to penetrate into the fruit. These findings indicate that cAMP-dependent protein kinase A has an important role in regulating morphogenesis and is required for pathogenicity of C. gloeosporioides. PMID:22666136

Dysbindin-1, WAVE2 and Abi-1 form a complex that regulates dendritic spine formation.

PubMed

Ito, H; Morishita, R; Shinoda, T; Iwamoto, I; Sudo, K; Okamoto, K; Nagata, K

2010-10-01

Genetic variations in dysbindin-1 (dystrobrevin-binding protein-1) are one of the most commonly reported variations associated with schizophrenia. As schizophrenia could be regarded as a neurodevelopmental disorder resulting from abnormalities of synaptic connectivity, we attempted to clarify the function of dysbindin-1 in neuronal development. We examined the developmental change of dysbindin-1 in rat brain by western blotting and found that a 50 kDa isoform is highly expressed during the embryonic stage, whereas a 40 kDa one is detected at postnatal day 11 and increased thereafter. Immunofluorescent analyses revealed that dysbindin-1 is enriched at the spine-like structure of primary cultured rat hippocampal neurons. We identified WAVE2, but not N-WASP, as a binding partner for dysbindin-1. We also found that Abi-1, a binding molecule for WAVE2 involved in spine morphogenesis, interacts with dysbindin-1. Although dysbindin-1, WAVE2 and Abi-1 form a ternary complex, dysbindin-1 promoted the binding of WAVE2 to Abi-1. RNA interference-mediated knockdown of dysbindin-1 led to the generation of abnormally elongated immature dendritic protrusions. The present results indicate possible functions of dysbindin-1 at the postsynapse in the regulation of dendritic spine morphogenesis through the interaction with WAVE2 and Abi-1.

Expression of genes responsible for cell morphogenesis involved in differentiation in porcine buccal pouch mucosal cells during long-term primary culture and real-time proliferation in vitro.

PubMed

Dyszkiewicz-Konwińska, M; Bryja, A; Jopek, K; Budna, J; Khozmi, R; Jeseta, M; Bukowska, D; Antosik, P; Bruska, M; Nowicki, M; Zabel, M; Kempisty, B

2017-01-01

Recently, using experimental animal model, we demonstrated that porcine buccal pouch mucosal cells reflect increased proliferation capability during primary cultivation in vitro. Although the histological structure and morphogenesis in oral cavity is well recognized, the molecular mechanisms which regulate this process still need further investigation. This study was aimed to analyze the molecular marker expression profile involved in morphogenesis and differentiation capacity of porcine buccal pouch mucosal cells during their long-term primary cultivation in vitro. The experiment was performed on buccal pouch mucosal cells isolated from 80 pubertal crossbred Landrace gilts. After collection, the cells were treated enzymatically and transferred into a primary in vitro culture (IVC) system and cultured for 30 days. The cells were collected for RNA isolation after 7, 15 and 30 days of IVC and were checked for their real-time proliferative status using the RTCA system. We found an increased expression of FN1 and SOX9 genes when calculated against ACTB after 7, and 30 days of IVC, (P less than 0.01, P less than 0.001, respectively). The CXCL12 mRNA was down-regulated after 7, 15 and 30 days of IVC, but not statistically significant. Similar expression profile was observed when calculated against HPRT, however, DAB2 was found to be higher expressed at day 15 of IVC, (P less than 0.05). The cell index measured during real-time cell proliferation was substantially increased between 96 h and 147h of IVC and reached the log phase. Since FN1 and SOX9 revealed significant increase of expression after long-term culture in vitro, it is suggested that expression of these differentiation and stemness genes is accompanied by cell proliferation. Moreover, FN1 and SOX9 might be recognized as new markers of buccal pouch mucosal cell proliferation and differentiation in pigs in in vitro primary culture model.

ETS transcription factor ELF5 induces lumen formation in a 3D model of mammary morphogenesis and its expression is inhibited by Jak2 inhibitor TG101348.

PubMed

Chean, Jennifer; Chen, Charng-Jui; Shively, John E

2017-10-01

The loss of expression of a single gene can revert normal tissue to a malignant phenotype. For example, while normal breast has high lumenal expression of CEACAM1, the majority of breast cancers exhibit the early loss of this gene with the concurrent loss of their lumenal phenotype. MCF7 cells that lack CEACAM1 expression and fail to form lumena in 3D culture, regain the normal phenotype when transfected with CEACAM1. In order to probe the mechanism of this gain of function, we treated these cells with the clinically relevant Jak2 inhibitor TG101348 (TG), expecting that disruption of the prolactin receptor signaling pathway would interfere with the positive effects of transfection of MCF7 cells with CEACAM1. Indeed, lumen formation was inhibited, resulting in the down regulation of a set of genes, likely involved in the complex process of lumen formation. As expected, inhibition of the expression of many of these genes also inhibited lumen formation, confirming their involvement in a single pathway. Among the genes identified by the inhibition assay, ETS transcription factor ELF5 stood out, since it has been identified as a master regulator of mammary morphogenesis, and is associated with prolactin receptor signaling. When ELF5 was transfected into the parental MCF7 cells that lack CEACAM1, lumen formation was restored, indicating that ELF5 can replace CEACAM1 in this model system of lumenogenesis. We conclude that the event(s) that led to the loss of expression of CEACAM1 is epistatic in that multiple genes associated with a critical pathway were affected, but that restoration of the normal phenotype can be achieved with reactivation of certain genes at various nodal points in tissue morphogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

The pleiotropic roles of transforming growth factor beta inhomeostasis and carcinogenesis of endocrine organs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleisch, Markus C.; Maxwell, Christopher A.; Barcellos-Hoff,Mary-Helen

2006-01-13

Transforming growth factor beta (TGF-beta) is a ubiquitous cytokine that plays a critical role in numerous pathways regulating cellular and tissue homeostasis. TGF-beta is regulated by hormones and is a primary mediator of hormone response in uterus, prostate and mammary gland. This review will address the role of TGF-beta in regulating hormone dependent proliferation and morphogenesis. The subversion of TGF-beta regulation during the processes of carcinogenesis, with particular emphasis on its effects on genetic stability and epithelial to mesenchymal transition (EMT), will also be examined. An understanding of the multiple and complex mechanisms of TGF-beta regulation of epithelial function, andmore » the ultimate loss of TGF-beta function during carcinogenesis, will be critical in the design of novel therapeutic interventions for endocrine-related cancers.« less

High sequence variations in the region containing genes encoding a cellular morphogenesis protein and the repressor of sexual development help to reveal origins of Aspergillus oryzae.

PubMed

Chang, Perng-Kuang; Scharfenstein, Leslie L; Solorzano, Cesar D; Abbas, Hamed K; Hua, Sui-Sheng T; Jones, Walker A; Zablotowicz, Robert M

2015-05-04

Aspergillus oryzae and Aspergillus flavus are closely related fungal species. The A. flavus morphotype that produces numerous small sclerotia (S strain) and aflatoxin has a unique 1.5 kb deletion in the norB-cypA region of the aflatoxin gene cluster (i.e. the S genotype). Phylogenetic studies have indicated that an isolate of the nonaflatoxigenic A. flavus with the S genotype is the ancestor of A. oryzae. Genome sequence comparison between A. flavus NRRL3357, which produces large sclerotia (L strain), and S-strain A. flavus 70S identified a region (samA-rosA) that was highly variable in the two morphotypes. A third type of samA-rosA region was found in A. oryzae RIB40. The three samA-rosA types were later revealed to be commonly present in A. flavus L-strain populations. Of the 182 L-strain A. flavus field isolates examined, 46%, 15% and 39% had the samA-rosA type of NRRL3357, 70S and RIB40, respectively. The three types also were found in 18 S-strain A. flavus isolates with different proportions. For A. oryzae, however, the majority (80%) of the 16 strains examined had the RIB40 type and none had the NRRL3357 type. The results suggested that A. oryzae strains in the current culture collections were mostly derived from the samA-rosA/RIB40 lineage of the nonaflatoxigenic A. flavus with the S genotype. Published by Elsevier B.V.

VEGF signaling inside vascular endothelial cells and beyond

PubMed Central

Eichmann, Anne; Simons, Michael

2014-01-01

Vascular endothelial growth factor-A (VEGF-A) has long been recognized as the key regulator of vascular development and function in health and disease. VEGF is a secreted polypeptide that binds to transmembrane tyrosine kinase VEGF receptors on the plasma membrane, inducing their dimerization, activation and assembly of a membrane-proximal signaling complex. Recent studies have revealed that many key events of VEGFR signaling occur inside the endothelial cell and are regulated by endosomal receptor trafficking. Plasma membrane VEGFR interacting molecules, including vascular guidance receptors Neuropilins and Ephrins also regulate VEGFR endocytosis and trafficking. VEGF signaling is increasingly recognized for its roles outside of the vascular system, notably during neural development, and blood vessels regulate epithelial branching morphogenesis. We review here recent advances in our understanding of VEGF signaling and its biological roles. PMID:22366328

Tegument Protein ORF45 Plays an Essential Role in Virion Morphogenesis of Murine Gammaherpesvirus 68

PubMed Central

Jia, Xing; Shen, Sheng; Lv, Ying; Zhang, Ziwei; Guo, Haitao

2016-01-01

Tegument proteins play critical roles in herpesvirus morphogenesis. ORF45 is a conserved tegument protein of gammaherpesviruses; however, its role in virion morphogenesis is largely unknown. In this work, we determined the ultrastructural localization of murine gammaherpesvirus 68 (MHV-68) ORF45 and found that this protein was incorporated into virions around the site of host-derived vesicles. Notably, the absence of ORF45 inhibited nucleocapsid egress and blocked cytoplasmic virion maturation, demonstrating that ORF45 is essential for MHV-68 virion morphogenesis. PMID:27226376

Evolution-development congruence in pattern formation dynamics: Bifurcations in gene expression and regulation of networks structures.

PubMed

Kohsokabe, Takahiro; Kaneko, Kunihiko

2016-01-01

Search for possible relationships between phylogeny and ontogeny is important in evolutionary-developmental biology. Here we uncover such relationships by numerical evolution and unveil their origin in terms of dynamical systems theory. By representing developmental dynamics of spatially located cells with gene expression dynamics with cell-to-cell interaction under external morphogen gradient, gene regulation networks are evolved under mutation and selection with the fitness to approach a prescribed spatial pattern of expressed genes. For most numerical evolution experiments, evolution of pattern over generations and development of pattern by an evolved network exhibit remarkable congruence. Both in the evolution and development pattern changes consist of several epochs where stripes are formed in a short time, while for other temporal regimes, pattern hardly changes. In evolution, these quasi-stationary regimes are generations needed to hit relevant mutations, while in development, they are due to some gene expression that varies slowly and controls the pattern change. The morphogenesis is regulated by combinations of feedback or feedforward regulations, where the upstream feedforward network reads the external morphogen gradient, and generates a pattern used as a boundary condition for the later patterns. The ordering from up to downstream is common in evolution and development, while the successive epochal changes in development and evolution are represented as common bifurcations in dynamical-systems theory, which lead to the evolution-development congruence. Mechanism of exceptional violation of the congruence is also unveiled. Our results provide a new look on developmental stages, punctuated equilibrium, developmental bottlenecks, and evolutionary acquisition of novelty in morphogenesis. © 2015 The Authors. Journal of Experimental Zoology Part B: Molecular and Developmental Evolution Published by Wiley Periodicals, Inc.

Evolution‐development congruence in pattern formation dynamics: Bifurcations in gene expression and regulation of networks structures

PubMed Central

Kohsokabe, Takahiro

2016-01-01

ABSTRACT Search for possible relationships between phylogeny and ontogeny is important in evolutionary‐developmental biology. Here we uncover such relationships by numerical evolution and unveil their origin in terms of dynamical systems theory. By representing developmental dynamics of spatially located cells with gene expression dynamics with cell‐to‐cell interaction under external morphogen gradient, gene regulation networks are evolved under mutation and selection with the fitness to approach a prescribed spatial pattern of expressed genes. For most numerical evolution experiments, evolution of pattern over generations and development of pattern by an evolved network exhibit remarkable congruence. Both in the evolution and development pattern changes consist of several epochs where stripes are formed in a short time, while for other temporal regimes, pattern hardly changes. In evolution, these quasi‐stationary regimes are generations needed to hit relevant mutations, while in development, they are due to some gene expression that varies slowly and controls the pattern change. The morphogenesis is regulated by combinations of feedback or feedforward regulations, where the upstream feedforward network reads the external morphogen gradient, and generates a pattern used as a boundary condition for the later patterns. The ordering from up to downstream is common in evolution and development, while the successive epochal changes in development and evolution are represented as common bifurcations in dynamical‐systems theory, which lead to the evolution‐development congruence. Mechanism of exceptional violation of the congruence is also unveiled. Our results provide a new look on developmental stages, punctuated equilibrium, developmental bottlenecks, and evolutionary acquisition of novelty in morphogenesis. J. Exp. Zool. (Mol. Dev. Evol.) 326B:61–84, 2016. © 2015 The Authors. Journal of Experimental Zoology Part B: Molecular and Developmental Evolution Published by Wiley Periodicals, Inc. PMID:26678220

Prx1 and Prx2 cooperatively regulate the morphogenesis of the medial region of the mandibular process

PubMed Central

Balic, Anamaria; Adams, Douglas; Mina, Mina

2009-01-01

Mice lacking both Prx1 and Prx2 display severe abnormalities in the mandible. Our analysis showed that complete loss of Prx gene products leads to growth abnormalities in the mandibular processes evident as early as E10.5 associated with changes in the survival of the mesenchyme in the medial region. Changes in the gene expression in the medial and lateral regions were related to gradual loss of a subpopulation of mesenchyme in the medial region expressing eHand. Our analysis also showed that Prx gene products are required for the initiation and maintenance of chondrogenesis and terminal differentiation of the chondrocytes in the caudal and rostral ends of Meckel’s cartilage. The fusion of the mandibular processes in the Prx1/Prx2 double mutants is caused by accelerated ossification. These observations together show that during mandibular morphogenesis Prx gene products play multiple roles including the cell survival, the region-specific terminal differentiation of Meckelian chondrocytes and osteogenesis. PMID:19777594

A transcriptomics resource reveals a transcriptional transition during ordered sarcomere morphogenesis in flight muscle.

PubMed

Spletter, Maria L; Barz, Christiane; Yeroslaviz, Assa; Zhang, Xu; Lemke, Sandra B; Bonnard, Adrien; Brunner, Erich; Cardone, Giovanni; Basler, Konrad; Habermann, Bianca H; Schnorrer, Frank

2018-05-30

Muscles organise pseudo-crystalline arrays of actin, myosin and titin filaments to build force-producing sarcomeres. To study sarcomerogenesis, we have generated a transcriptomics resource of developing Drosophila flight muscles and identified 40 distinct expression profile clusters. Strikingly, most sarcomeric components group in two clusters, which are strongly induced after all myofibrils have been assembled, indicating a transcriptional transition during myofibrillogenesis. Following myofibril assembly, many short sarcomeres are added to each myofibril. Subsequently, all sarcomeres mature, reaching 1.5 µm diameter and 3.2 µm length and acquiring stretch-sensitivity. The efficient induction of the transcriptional transition during myofibrillogenesis, including the transcriptional boost of sarcomeric components, requires in part the transcriptional regulator Spalt major. As a consequence of Spalt knock-down, sarcomere maturation is defective and fibers fail to gain stretch-sensitivity. Together, this defines an ordered sarcomere morphogenesis process under precise transcriptional control - a concept that may also apply to vertebrate muscle or heart development. © 2018, Spletter et al.

Anti-Urokinase Receptor Antisense Oligonucleotide (uPAR-aODN) to Prevent and Cure Long-Term Space Exploration-Related Retinal Pathological Angiogenesis

NASA Astrophysics Data System (ADS)

Lazzarano, Stefano; Lulli, Matteo; Fibbi, Gabriella; Margheri, Francesca; Papucci, Laura; Serrati, Simona; Witort, Ewa; Chilla, Anastasia; Lapucci, Andrea; Donnini, Martino; Quaglierini, Paolo; Romiti, Alice; Specogna, Rebecca; Del Rosso, Mario; Capaccioli, Sergio

2008-06-01

Angiogenesis underlies a variety of physiological processes and its possible deregulation during long term space exploration needs to be investigated. Angiogenesis is a multistep process of new blood capillary formation, where degradation of the extracellular matrix (ECM) by proteolytic enzymes, including uPA (urokinase plasminogen activator) and opening the way to migration of endothelial cells (EC), is critical. Plasminogen activation system regulates angiogenesis by both uPA-driven ECM degradation and uPA receptor (uPAR). Microgravity and low dose irradiations promote tissue neoangiogeenesis and neovascularization is often common occurence in ophthalmologic pathologies. We have designed and patented the uPAR antisense oligonucleotide (aODN) and evaluated its antiangiogenetic activity by EC cellular migration and capillary morphogenesis assays. The uPAR aODN treatment caused a 75% inhibition of human microvascular EC migration and a complete inhibition of capillary morphogenesis, suggesting its therapeutic application to prevent neoangiogenesis-related ophthalmologic pathologies during space exploration.

Bone morphogenetic protein-4 strongly potentiates growth factor-induced proliferation of mammary epithelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montesano, Roberto; Sarkoezi, Rita; Schramek, Herbert

2008-09-12

Bone morphogenetic proteins (BMPs) are multifunctional cytokines that elicit pleiotropic effects on biological processes such as cell proliferation, cell differentiation and tissue morphogenesis. With respect to cell proliferation, BMPs can exert either mitogenic or anti-mitogenic activities, depending on the target cells and their context. Here, we report that in low-density cultures of immortalized mammary epithelial cells, BMP-4 did not stimulate cell proliferation by itself. However, when added in combination with suboptimal concentrations of fibroblast growth factor (FGF)-2, FGF-7, FGF-10, epidermal growth factor (EGF) or hepatocyte growth factor (HGF), BMP-4 potently enhanced growth factor-induced cell proliferation. These results reveal a hithertomore » unsuspected interplay between BMP-4 and growth factors in the regulation of mammary epithelial cell proliferation. We suggest that the ability of BMP-4 to potentiate the mitogenic activity of multiple growth factors may contribute to mammary gland ductal morphogenesis as well as to breast cancer progression.« less

Mechanical Forces Program the Orientation of Cell Division during Airway Tube Morphogenesis.

PubMed

Tang, Zan; Hu, Yucheng; Wang, Zheng; Jiang, Kewu; Zhan, Cheng; Marshall, Wallace F; Tang, Nan

2018-02-05

Oriented cell division plays a key role in controlling organogenesis. The mechanisms for regulating division orientation at the whole-organ level are only starting to become understood. By combining 3D time-lapse imaging, mouse genetics, and mathematical modeling, we find that global orientation of cell division is the result of a combination of two types of spindles with distinct spindle dynamic behaviors in the developing airway epithelium. Fixed spindles follow the classic long-axis rule and establish their division orientation before metaphase. In contrast, rotating spindles do not strictly follow the long-axis rule and determine their division orientation during metaphase. By using both a cell-based mechanical model and stretching-lung-explant experiments, we showed that mechanical force can function as a regulatory signal in maintaining the stable ratio between fixed spindles and rotating spindles. Our findings demonstrate that mechanical forces, cell geometry, and oriented cell division function together in a highly coordinated manner to ensure normal airway tube morphogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Myosin-II controls cellular branching morphogenesis and migration in 3D by minimizing cell surface curvature

PubMed Central

Elliott, Hunter; Fischer, Robert A.; Myers, Kenneth A.; Desai, Ravi A.; Gao, Lin; Chen, Christopher S.; Adelstein, Robert; Waterman, Clare M.; Danuser, Gaudenz

2014-01-01

In many cases cell function is intimately linked to cell shape control. We utilized endothelial cell branching morphogenesis as a model to understand the role of myosin-II in shape control of invasive cells migrating in 3D collagen gels. We applied principles of differential geometry and mathematical morphology to 3D image sets to parameterize cell branch structure and local cell surface curvature. We find that Rho/ROCK-stimulated myosin-II contractility minimizes cell-scale branching by recognizing and minimizing local cell surface curvature. Utilizing micro-fabrication to constrain cell shape identifies a positive feedback mechanism in which low curvature stabilizes myosin-II cortical association, where it acts to maintain minimal curvature. The feedback between myosin-II regulation by and control of curvature drives cycles of localized cortical myosin-II assembly and disassembly. These cycles in turn mediate alternating phases of directionally biased branch initiation and retraction to guide 3D cell migration. PMID:25621949

LGN plays distinct roles in oral epithelial stratification, filiform papilla morphogenesis and hair follicle development

PubMed Central

Lough, Kendall J.; Patel, Jeet H.; Descovich, Carlos Patiño; Curtis, T. Anthony

2016-01-01

Oral epithelia protect against constant challenges by bacteria, viruses, toxins and injury while also contributing to the formation of ectodermal appendages such as teeth, salivary glands and lingual papillae. Despite increasing evidence that differentiation pathway genes are frequently mutated in oral cancers, comparatively little is known about the mechanisms that regulate normal oral epithelial development. Here, we characterize oral epithelial stratification and describe multiple distinct functions for the mitotic spindle orientation gene LGN (Gpsm2) in promoting differentiation and tissue patterning in the mouse oral cavity. Similar to its function in epidermis, apically localized LGN directs perpendicular divisions that promote stratification of the palatal, buccogingival and ventral tongue epithelia. Surprisingly, however, in dorsal tongue LGN is predominantly localized basally, circumferentially or bilaterally and promotes planar divisions. Loss of LGN disrupts the organization and morphogenesis of filiform papillae but appears to be dispensable for embryonic hair follicle development. Thus, LGN has crucial tissue-specific functions in patterning surface ectoderm and its appendages by controlling division orientation. PMID:27317810

Autonomy and Non-autonomy of Angiogenic Cell Movements Revealed by Experiment-Driven Mathematical Modeling.

PubMed

Sugihara, Kei; Nishiyama, Koichi; Fukuhara, Shigetomo; Uemura, Akiyoshi; Arima, Satoshi; Kobayashi, Ryo; Köhn-Luque, Alvaro; Mochizuki, Naoki; Suda, Toshio; Ogawa, Hisao; Kurihara, Hiroki

2015-12-01

Angiogenesis is a multicellular phenomenon driven by morphogenetic cell movements. We recently reported morphogenetic vascular endothelial cell (EC) behaviors to be dynamic and complex. However, the principal mechanisms orchestrating individual EC movements in angiogenic morphogenesis remain largely unknown. Here we present an experiment-driven mathematical model that enables us to systematically dissect cellular mechanisms in branch elongation. We found that cell-autonomous and coordinated actions governed these multicellular behaviors, and a cell-autonomous process sufficiently illustrated essential features of the morphogenetic EC dynamics at both the single-cell and cell-population levels. Through refining our model and experimental verification, we further identified a coordinated mode of tip EC behaviors regulated via a spatial relationship between tip and follower ECs, which facilitates the forward motility of tip ECs. These findings provide insights that enhance our mechanistic understanding of not only angiogenic morphogenesis, but also other types of multicellular phenomenon. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

YAP is essential for mechanical force production and epithelial cell proliferation during lung branching morphogenesis

PubMed Central

Lin, Chuwen; Yao, Erica; Zhang, Kuan; Jiang, Xuan; Croll, Stacey; Thompson-Peer, Katherine; Chuang, Pao-Tien

2017-01-01

Branching morphogenesis is a fundamental program for tissue patterning. We show that active YAP, a key mediator of Hippo signaling, is distributed throughout the murine lung epithelium and loss of epithelial YAP severely disrupts branching. Failure to branch is restricted to regions where YAP activity is removed. This suggests that YAP controls local epithelial cell properties. In support of this model, mechanical force production is compromised and cell proliferation is reduced in Yap mutant lungs. We propose that defective force generation and insufficient epithelial cell number underlie the branching defects. Through genomic analysis, we also uncovered a feedback control of pMLC levels, which is critical for mechanical force production, likely through the direct induction of multiple regulators by YAP. Our work provides a molecular pathway that could control epithelial cell properties required for proper morphogenetic movement and pattern formation. DOI: http://dx.doi.org/10.7554/eLife.21130.001 PMID:28323616

Intestinal development and differentiation

PubMed Central

Noah, Taeko K.; Donahue, Bridgitte; Shroyer, Noah F.

2011-01-01

In this review, we present an overview of intestinal development and cellular differentiation of the intestinal epithelium. The review is separated into two sections: Section one summarizes organogenesis of the small and large intestines, including endoderm and gut tube formation in early embryogenesis, villus morphogenesis, and crypt formation. Section two reviews cell fate specification and differentiation of each cell type within the intestinal epithelium. Growth factor and transcriptional networks that regulate these developmental processes are summarized. PMID:21978911

Developmental expression of Hsp90, Hsp70 and HSF during morphogenesis in the vetigastropod Haliotis asinina.

PubMed

Gunter, Helen M; Degnan, Bernard M

2007-08-01

Heat shock proteins (Hsps) have dual functions, participating in both the stress response and a broad range of developmental processes. At physiological temperatures, it has been demonstrated in deuterostomes (vertebrates) and ecdysozoans (insects) that Hsps are expressed in tissues that are undergoing differentiation and morphogenesis. Here we investigate the developmental expression of Hsp70, Hsp90 and their regulatory transcription factor heat shock transcription factor (HSF) in the marine gastropod Haliotis asinina, a representative of the 3rd major lineage of bilaterian animals, the Lophotrochozoa. HasHsp70, HasHsp90 and HasHSF are maternally expressed in H. asinina and are progressively restricted to the micromere lineage during cleavage. During larval morphogenesis, they are expressed in unique and overlapping patterns in the prototroch, foot, and mantle. Hsp expression peaked in these tissues during periods of cell differentiation and morphogenesis, returning to lower levels after morphogenesis was complete. These patterns of Hsp and HSF expression in H. asinina are akin to those observed in ecdysozoans and deuterostomes, with Hsps being activated in cells and tissues undergoing morphogenesis.

Morphogenesis and Biomechanics of Engineered Skin Cultured Under Uniaxial Strain.

PubMed

Blackstone, Britani N; Powell, Heather M

2012-04-01

Split-thickness autograft is the standard wound treatment for full-thickness burns. In large burns, sparse availability of uninjured skin prevents rapid closure of the wound, resulting in increased scar tissue formation or mortality. Tissue-engineered skin (ES) offers promise when autografts are not available. ES, constructed from a polymeric scaffold and skin cells, has been shown to reduce donor site area required to permanently close wounds, mortality, and morbidity from scarring but cannot restore all skin functions. Current generations of ES are orders of magnitude weaker than normal human skin, leading to difficulty in surgical application, greater susceptibility to mechanical damage during fabrication and application, and less elasticity and strength once engrafted. Previous studies to improve ES biomechanics focus on altering the scaffolding material, which resulted in modest improvements but often inhibited proper skin development. As the skin is naturally under static strain, adding these mechanical cues to the culture environment is hypothesized to improve ES biomechanics. ES was cultured under applied static strains ranging from 0% to 40% strain for a total of 10 days. Strain magnitudes of 10% and 20% strain resulted in significantly stronger ES than unstrained controls, showed upregulation of many genes encoding structural extracellular matrix proteins, and exhibited increased epidermal cell proliferation and differentiation. Enhanced biomechanical properties of ES can allow for facile surgical application and less damage during dressing changes. These findings suggest that mechanical cues play a significant role in skin development and should be further explored.

The case for applying tissue engineering methodologies to instruct human organoid morphogenesis.

PubMed

Marti-Figueroa, Carlos R; Ashton, Randolph S

2017-05-01

Three-dimensional organoids derived from human pluripotent stem cell (hPSC) derivatives have become widely used in vitro models for studying development and disease. Their ability to recapitulate facets of normal human development during in vitro morphogenesis produces tissue structures with unprecedented biomimicry. Current organoid derivation protocols primarily rely on spontaneous morphogenesis processes to occur within 3-D spherical cell aggregates with minimal to no exogenous control. This yields organoids containing microscale regions of biomimetic tissues, but at the macroscale (i.e. 100's of microns to millimeters), the organoids' morphology, cytoarchitecture, and cellular composition are non-biomimetic and variable. The current lack of control over in vitro organoid morphogenesis at the microscale induces aberrations at the macroscale, which impedes realization of the technology's potential to reproducibly form anatomically correct human tissue units that could serve as optimal human in vitro models and even transplants. Here, we review tissue engineering methodologies that could be used to develop powerful approaches for instructing multiscale, 3-D human organoid morphogenesis. Such technological mergers are critically needed to harness organoid morphogenesis as a tool for engineering functional human tissues with biomimetic anatomy and physiology. Human PSC-derived 3-D organoids are revolutionizing the biomedical sciences. They enable the study of development and disease within patient-specific genetic backgrounds and unprecedented biomimetic tissue microenvironments. However, their uncontrolled, spontaneous morphogenesis at the microscale yields inconsistences in macroscale organoid morphology, cytoarchitecture, and cellular composition that limits their standardization and application. Integration of tissue engineering methods with organoid derivation protocols could allow us to harness their potential by instructing standardized in vitro morphogenesis to generate organoids with biomimicry at all scales. Such advancements would enable the use of organoids as a basis for 'next-generation' tissue engineering of functional, anatomically mimetic human tissues and potentially novel organ transplants. Here, we discuss critical aspects of organoid morphogenesis where application of innovative tissue engineering methodologies would yield significant advancement towards this goal. Copyright © 2017. Published by Elsevier Ltd.

Reprogramming cells and tissue patterning via bioelectrical pathways: molecular mechanisms and biomedical opportunities

PubMed Central

Levin, Michael

2013-01-01

Transformative impact in regenerative medicine requires more than the reprogramming of individual cells: advances in repair strategies for birth defects or injuries, tumor normalization, and the construction of bioengineered organs and tissues all require the ability to control large-scale anatomical shape. Much recent work has focused on the transcriptional and biochemical regulation of cell behaviour and morphogenesis. However, exciting new data reveal that bioelectrical properties of cells and their microenvironment exert a profound influence on cell differentiation, proliferation, and migration. Ion channels and pumps expressed in all cells, not just excitable nerve and muscle, establish resting potentials that vary across tissues and change with significant developmental events. Most importantly, the spatio-temporal gradients of these endogenous transmembrane voltage potentials (Vmem) serve as instructive patterning cues for large-scale anatomy, providing organ identity, positional information, and prepattern template cues for morphogenesis. New genetic and pharmacological techniques for molecular modulation of bioelectric gradients in vivo have revealed the ability to initiate complex organogenesis, change tissue identity, and trigger regeneration of whole vertebrate appendages. A large segment of the spatial information processing that orchestrates individual cells’ programs towards the anatomical needs of the host organism is electrical; this blurs the line between memory and decision-making in neural networks and morphogenesis in non-neural tissues. Advances in cracking this bioelectric code will enable the rational reprogramming of shape in whole tissues and organs, revolutionizing regenerative medicine, developmental biology, and synthetic bioengineering. PMID:23897652

Comparative transcriptome analysis reveals conserved branching morphogenesis related genes involved in chamber formation of catfish swimbladder.

PubMed

Yang, Yujia; Fu, Qiang; Liu, Yang; Wang, Xiaozhu; Dunham, Rex; Liu, Shikai; Bao, Lisui; Zeng, Qifan; Zhou, Tao; Li, Ning; Qin, Zhenkui; Jiang, Chen; Gao, Dongya; Liu, Zhanjiang

2018-01-01

The swimbladder is an internal gas-filled organ in teleosts. Its major function is to regulate buoyancy. The swimbladder exhibits great variation in size, shape, and number of compartments or chambers among teleosts. However, genomic control of swimbladder variation is unknown. Channel catfish ( Ictalurus punctatus), blue catfish ( Ictalurus furcatus), and their F1 hybrids of female channel catfish × male blue catfish (C × B hybrid catfish) provide a good model in which to investigate the swimbladder morphology, because channel catfish possess a single-chambered swimbladder, whereas blue catfish possess a bichambered swimbladder; C × B hybrid catfish possess a bichambered swimbladder but with a significantly reduced posterior chamber. Here we determined the transcriptional profiles of swimbladder from channel catfish, blue catfish, and C × B hybrid catfish. We examined their transcriptomes at both the fingerling and adult stages. Through comparative transcriptome analysis, ~4,000 differentially expressed genes (DEGs) were identified. Among these DEGs, members of the Wnt signaling pathway ( wnt1, wnt2, nfatc1, rac2), Hedgehog signaling pathway ( shh), and growth factors ( fgf10, igf-1) were identified. As these genes were known to be important for branching morphogenesis of mammalian lung and of mammary glands, their association with budding of the posterior chamber primordium and progressive development of bichambered swimbladder in fish suggest that these branching morphogenesis-related genes and their functions in branching are evolutionarily conserved across a broad spectrum of species.

Drosophila glypican Dally-like acts in FGF-receiving cells to modulate FGF signaling during tracheal morphogenesis

PubMed Central

Yan, Dong; Lin, Xinhua

2007-01-01

Summary Previous studies in Drosophila have shown that heparan sulfate proteoglycans (HSPGs) are involved in both breathless (btl)- and heartless (htl)-mediated FGF signaling during embryogenesis. However, the mechanism(s) by which HSPGs control Btl and Htl signaling is unknown. Here we show that dally-like (dlp, a Drosophila glypican) mutant embryos exhibit severe defects in tracheal morphogenesis and show a reduction in btl-mediated FGF signaling activity. However, htl-dependent mesodermal cell migration is not affected in dlp mutant embryos. Furthermore, expression of Dlp, but not other Drosophila HSPGs, can restore effectively the tracheal morphogenesis in dlp embryos. Rescue experiments in dlp embryos demonstrate that Dlp functions only in Bnl/FGF receiving cells in a cell-autonomous manner, but is not essential for Bnl/FGF expression cells. To further dissect the mechanism(s) of Dlp in Btl signaling, we analyzed the role of Dlp in Btl-mediated air sac tracheoblast formation in wing discs. Mosaic analysis experiments show that removal of HSPG activity in FGF-producing or other surrounding cells does not affect tracheoblasts migration, while HSPG mutant tracheoblast cells fail to receive FGF signaling. Together, our results argue strongly that HSPGs regulate Btl signaling exclusively in FGF-receiving cells as co-receptors, but are not essential for the secretion and distribution of the FGF ligand. This mechanism is distinct from HSPG functions in morphogen distribution, and is likely a general paradigm for HSPG functions in FGF signaling in Drosophila. PMID:17959166

A Computational Framework for 3D Mechanical Modeling of Plant Morphogenesis with Cellular Resolution

PubMed Central

Gilles, Benjamin; Hamant, Olivier; Boudaoud, Arezki; Traas, Jan; Godin, Christophe

2015-01-01

The link between genetic regulation and the definition of form and size during morphogenesis remains largely an open question in both plant and animal biology. This is partially due to the complexity of the process, involving extensive molecular networks, multiple feedbacks between different scales of organization and physical forces operating at multiple levels. Here we present a conceptual and modeling framework aimed at generating an integrated understanding of morphogenesis in plants. This framework is based on the biophysical properties of plant cells, which are under high internal turgor pressure, and are prevented from bursting because of the presence of a rigid cell wall. To control cell growth, the underlying molecular networks must interfere locally with the elastic and/or plastic extensibility of this cell wall. We present a model in the form of a three dimensional (3D) virtual tissue, where growth depends on the local modulation of wall mechanical properties and turgor pressure. The model shows how forces generated by turgor-pressure can act both cell autonomously and non-cell autonomously to drive growth in different directions. We use simulations to explore lateral organ formation at the shoot apical meristem. Although different scenarios lead to similar shape changes, they are not equivalent and lead to different, testable predictions regarding the mechanical and geometrical properties of the growing lateral organs. Using flower development as an example, we further show how a limited number of gene activities can explain the complex shape changes that accompany organ outgrowth. PMID:25569615

Reprogramming cells and tissue patterning via bioelectrical pathways: molecular mechanisms and biomedical opportunities.

PubMed

Levin, Michael

2013-01-01

Transformative impact in regenerative medicine requires more than the reprogramming of individual cells: advances in repair strategies for birth defects or injuries, tumor normalization, and the construction of bioengineered organs and tissues all require the ability to control large-scale anatomical shape. Much recent work has focused on the transcriptional and biochemical regulation of cell behavior and morphogenesis. However, exciting new data reveal that bioelectrical properties of cells and their microenvironment exert a profound influence on cell differentiation, proliferation, and migration. Ion channels and pumps expressed in all cells, not just excitable nerve and muscle, establish resting potentials that vary across tissues and change with significant developmental events. Most importantly, the spatiotemporal gradients of these endogenous transmembrane voltage potentials (Vmem ) serve as instructive patterning cues for large-scale anatomy, providing organ identity, positional information, and prepattern template cues for morphogenesis. New genetic and pharmacological techniques for molecular modulation of bioelectric gradients in vivo have revealed the ability to initiate complex organogenesis, change tissue identity, and trigger regeneration of whole vertebrate appendages. A large segment of the spatial information processing that orchestrates individual cells' programs toward the anatomical needs of the host organism is electrical; this blurs the line between memory and decision-making in neural networks and morphogenesis in nonneural tissues. Advances in cracking this bioelectric code will enable the rational reprogramming of shape in whole tissues and organs, revolutionizing regenerative medicine, developmental biology, and synthetic bioengineering. Copyright © 2013 Wiley Periodicals, Inc.

Casein Kinase I Isoform Hrr25 Is a Negative Regulator of Haa1 in the Weak Acid Stress Response Pathway in Saccharomyces cerevisiae

PubMed Central

Collins, Morgan E.; Black, Joshua J.

2017-01-01

ABSTRACT Haa1 is a transcription factor that adapts Saccharomyces cerevisiae cells to weak organic acid stresses by activating the expression of various genes. Many of these genes encode membrane proteins, such as TPO2 and YRO2. How Haa1 is activated by weak acids is not clear. Here, we show that casein kinase I isoform Hrr25 is an important negative regulator of Haa1. Haa1 is known to be multiply phosphorylated. We found that mutations in HRR25 lead to reduced Haa1 phosphorylation and increased expression of Haa1 target genes and that Hrr25 interacts with Haa1. The other three casein kinase I isoforms, Yck1, Yck2, and Yck3, do not seem to play critical roles in Haa1 regulation. Hrr25 has a 200-residue C-terminal region, including a proline- and glutamine-rich domain. Our data suggest that the C-terminal region of Hrr25 is required for normal inhibition of expression of Haa1 target genes TPO2 and YRO2 and is important for cell growth but is not required for cell morphogenesis. We propose that Hrr25 is an important regulator of cellular adaptation to weak acid stress by inhibiting Haa1 through phosphorylation. IMPORTANCE Our study has revealed the casein kinase I protein Hrr25 to be a negative regulator of Haa1, a transcription factor mediating the cellular response to stresses caused by weak acids. Many studies have focused on the target genes of Haa1 and their roles in weak acid stress responses, but little has been reported on the regulatory mechanism of Haa1. Weak acids, such as acetic acid, have long been used for food preservation by slowing down the growth of fungal species, including S. cerevisiae. In the biofuel industry, acetic acid in the lignocellulosic hydrolysates limits the production of ethanol, which is undesirable. By understanding how Haa1 is regulated, we can make advances in the field of food sciences to better preserve food and engineer acetic acid-resistant strains that will increase productivity in the biofuel industry. PMID:28432100

Dicer-dependent endothelial microRNAs are necessary for postnatal angiogenesis.

PubMed

Suárez, Yajaira; Fernández-Hernando, Carlos; Yu, Jun; Gerber, Scott A; Harrison, Kenneth D; Pober, Jordan S; Iruela-Arispe, M Luisa; Merkenschlager, Matthias; Sessa, William C

2008-09-16

Posttranscriptional gene regulation by microRNAs (miRNAs) is important for many aspects of development, homeostasis, and disease. Here, we show that reduction of endothelial miRNAs by cell-specific inactivation of Dicer, the terminal endonuclease responsible for the generation of miRNAs, reduces postnatal angiogenic response to a variety of stimuli, including exogenous VEGF, tumors, limb ischemia, and wound healing. Furthermore, VEGF regulated the expression of several miRNAs, including the up-regulation of components of the c-Myc oncogenic cluster miR-17-92. Transfection of endothelial cells with components of the miR-17-92 cluster, induced by VEGF treatment, rescued the induced expression of thrombospondin-1 and the defect in endothelial cell proliferation and morphogenesis initiated by the loss of Dicer. Thus, endothelial miRNAs regulate postnatal angiogenesis and VEGF induces the expression of miRNAs implicated in the regulation of an integrated angiogenic response.

The Developmental Regulator SEEDSTICK Controls Structural and Mechanical Properties of the Arabidopsis Seed Coat

PubMed Central

Beauzamy, Léna; Caporali, Elisabetta; Koroney, Abdoul-Salam

2016-01-01

Although many transcription factors involved in cell wall morphogenesis have been identified and studied, it is still unknown how genetic and molecular regulation of cell wall biosynthesis is integrated into developmental programs. We demonstrate by molecular genetic studies that SEEDSTICK (STK), a transcription factor controlling ovule and seed integument identity, directly regulates PMEI6 and other genes involved in the biogenesis of the cellulose-pectin matrix of the cell wall. Based on atomic force microscopy, immunocytochemistry, and chemical analyses, we propose that structural modifications of the cell wall matrix in the stk mutant contribute to defects in mucilage release and seed germination under water-stress conditions. Our studies reveal a molecular network controlled by STK that regulates cell wall properties of the seed coat, demonstrating that developmental regulators controlling organ identity also coordinate specific aspects of cell wall characteristics. PMID:27624758

Protein Kinase D1 Signaling in Angiogenic Gene Expression and VEGF-Mediated Angiogenesis.

PubMed

Ren, Bin

2016-01-01

Protein kinase D 1 (PKD-1) is a signaling kinase important in fundamental cell functions including migration, proliferation, and differentiation. PKD-1 is also a key regulator of gene expression and angiogenesis that is essential for cardiovascular development and tumor progression. Further understanding molecular aspects of PKD-1 signaling in the regulation of angiogenesis may have translational implications in obesity, cardiovascular disease, and cancer. The author will summarize and provide the insights into molecular mechanisms by which PKD-1 regulates transcriptional expression of angiogenic genes, focusing on the transcriptional regulation of CD36 by PKD-1-FoxO1 signaling axis along with the potential implications of this axis in arterial differentiation and morphogenesis. He will also discuss a new concept of dynamic balance between proangiogenic and antiangiogenic signaling in determining angiogenic switch, and stress how PKD-1 signaling regulates VEGF signaling-mediated angiogenesis.

Protein Kinase D1 Signaling in Angiogenic Gene Expression and VEGF-Mediated Angiogenesis

PubMed Central

Ren, Bin

2016-01-01

Protein kinase D 1 (PKD-1) is a signaling kinase important in fundamental cell functions including migration, proliferation, and differentiation. PKD-1 is also a key regulator of gene expression and angiogenesis that is essential for cardiovascular development and tumor progression. Further understanding molecular aspects of PKD-1 signaling in the regulation of angiogenesis may have translational implications in obesity, cardiovascular disease, and cancer. The author will summarize and provide the insights into molecular mechanisms by which PKD-1 regulates transcriptional expression of angiogenic genes, focusing on the transcriptional regulation of CD36 by PKD-1-FoxO1 signaling axis along with the potential implications of this axis in arterial differentiation and morphogenesis. He will also discuss a new concept of dynamic balance between proangiogenic and antiangiogenic signaling in determining angiogenic switch, and stress how PKD-1 signaling regulates VEGF signaling-mediated angiogenesis. PMID:27200349

Interference by 2,3,7,8-tetrachlorodibenzo-p-dioxin with cultured mouse submandibular gland branching morphogenesis involves reduced epidermal growth factor receptor signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiukkonen, Anu; Sahlberg, Carin; Partanen, Anna-Maija

2006-05-01

Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to mouse embryonic teeth, sharing features of early development with salivary glands in common, involves enhanced apoptosis and depends on the expression of epidermal growth factor (EGF) receptor. EGF receptor signaling, on the other hand, is essential for salivary gland branching morphogenesis. To see if TCDD impairs salivary gland morphogenesis and if the impairment is associated with EGF receptor signaling, we cultured mouse (NMRI) E13 submandibular glands with TCDD or TCDD in combination with EGF or fibronectin (FN), both previously found to enhance branching morphogenesis. Explants were examined stereomicroscopically and processed to paraffin sections. TCDD exposuremore » impaired epithelial branching and cleft formation, resulting in enlarged buds. The glands were smaller than normal. EGF and FN alone concentration-dependently stimulated or inhibited branching morphogenesis but when co-administered with TCDD, failed to compensate for its effect. TCDD induced cytochrome P4501A1 expression in the glandular epithelium, indicating activation of the aryl hydrocarbon receptor. TCDD somewhat increased epithelial apoptosis as observed by terminal deoxynucleotidyl transferase (TdT)-mediated nick end-labeling method but the increase could not be correlated with morphological changes. The frequency of proliferating cells was not altered. Corresponding to the reduced cleft sites in TCDD-exposed explants, FN immunoreactivity in the epithelium was reduced. The results show that TCDD, comparably with EGF and FN at morphogenesis-inhibiting concentrations, impaired salivary gland branching morphogenesis in vitro. Together with the failure of EGF and FN at morphogenesis-stimulating concentrations to compensate for the effect of TCDD this implies that TCDD toxicity to developing salivary gland involves reduced EGF receptor signaling.« less

Arp2/3 and VASP Are Essential for Fear Memory Formation in Lateral Amygdala.

PubMed

Basu, Sreetama; Kustanovich, Irina; Lamprecht, Raphael

2016-01-01

The actin cytoskeleton is involved in key neuronal functions such as synaptic transmission and morphogenesis. However, the roles and regulation of actin cytoskeleton in memory formation remain to be clarified. In this study, we unveil the mechanism whereby actin cytoskeleton is regulated to form memory by exploring the roles of the major actin-regulatory proteins Arp2/3, VASP, and formins in long-term memory formation. Inhibition of Arp2/3, involved in actin filament branching and neuronal morphogenesis, in lateral amygdala (LA) with the specific inhibitor CK-666 during fear conditioning impaired long-term, but not short-term, fear memory. The inactive isomer CK-689 had no effect on memory formation. We observed that Arp2/3 is colocalized with the actin-regulatory protein profilin in LA neurons of fear-conditioned rats. VASP binding to profilin is needed for profilin-mediated stabilization of actin cytoskeleton and dendritic spine morphology. Microinjection of poly-proline peptide [G(GP 5 ) 3 ] into LA, to interfere with VASP binding to profilin, impaired long-term but not short-term fear memory formation. Control peptide [G(GA 5 ) 3 ] had no effect. Inhibiting formins, which regulate linear actin elongation, in LA during fear conditioning by microinjecting the formin-specific inhibitor SMIFH2 into LA had no effect on long-term fear memory formation. We conclude that Arp2/3 and VASP, through the profilin binding site, are essential for the formation of long-term fear memory in LA and propose a model whereby these proteins subserve cellular events, leading to memory consolidation.

Pax2 regulates a fadd-dependent molecular switch that drives tissue fusion during eye development.

PubMed

Viringipurampeer, Ishaq A; Ferreira, Todd; DeMaria, Shannon; Yoon, Jookyung J; Shan, Xianghong; Moosajee, Mariya; Gregory-Evans, Kevin; Ngai, John; Gregory-Evans, Cheryl Y

2012-05-15

Tissue fusion is an essential morphogenetic mechanism in development, playing a fundamental role in developing neural tube, palate and the optic fissure. Disruption of genes associated with the tissue fusion can lead to congenital malformations, such as spina bifida, cleft lip/palate and ocular coloboma. For instance, the Pax2 transcription factor is required for optic fissure closure, although the mechanism of Pax2 action leading to tissue fusion remains elusive. This lack of information defining how transcription factors drive tissue morphogenesis at the cellular level is hampering new treatments options. Through loss- and gain-of-function analysis, we now establish that pax2 in combination with vax2 directly regulate the fas-associated death domain (fadd) gene. In the presence of fadd, cell proliferation is restricted in the developing eye through a caspase-dependent pathway. However, the loss of fadd results in a proliferation defect and concomitant activation of the necroptosis pathway through RIP1/RIP3 activity, leading to an abnormal open fissure. Inhibition of RIP1 with the small molecule drug necrostatin-1 rescues the pax2 eye fusion defect, thereby overcoming the underlying genetic defect. Thus, fadd has an essential physiological function in protecting the developing optic fissure neuroepithelium from RIP3-dependent necroptosis. This study demonstrates the molecular hierarchies that regulate a cellular switch between proliferation and the apoptotic and necroptotic cell death pathways, which in combination drive tissue morphogenesis. Furthermore, our data suggest that future therapeutic strategies may be based on small molecule drugs that can bypass the gene defects causing common congenital tissue fusion defects.

TSH Receptor Function Is Required for Normal Thyroid Differentiation in Zebrafish

PubMed Central

Opitz, Robert; Maquet, Emilie; Zoenen, Maxime; Dadhich, Rajesh

2011-01-01

TSH is the primary physiological regulator of thyroid gland function. The effects of TSH on thyroid cells are mediated via activation of its membrane receptor [TSH receptor (TSHR)]. In this study, we examined functional thyroid differentiation in zebrafish and characterized the role of TSHR signaling during thyroid organogenesis. Cloning of a cDNA encoding zebrafish Tshr showed conservation of primary structure and functional properties between zebrafish and mammalian TSHR. In situ hybridization confirmed that the thyroid is the major site of tshr expression during zebrafish development. In addition, we identified tpo, iyd, duox, and duoxa as novel thyroid differentiation markers in zebrafish. Temporal analyses of differentiation marker expression demonstrated the induction of an early thyroid differentiation program along with thyroid budding, followed by a delayed onset of duox and duoxa expression coincident with thyroid hormone synthesis. Furthermore, comparative analyses in mouse and zebrafish revealed for the first time a thyroid-enriched expression of cell death regulators of the B-cell lymphoma 2 family during early thyroid morphogenesis. Knockdown of tshr function by morpholino microinjection into embryos did not affect early thyroid morphogenesis but caused defects in later functional differentiation. The thyroid phenotype observed in tshr morphants at later stages comprised a reduction in number and size of functional follicles, down-regulation of differentiation markers, as well as reduced thyroid transcription factor expression. A comparison of our results with phenotypes observed in mouse models of defective TSHR and cAMP signaling highlights the value of zebrafish as a model to enhance the understanding of functional differentiation in the vertebrate thyroid. PMID:21737742

Overexpression of microRNA319 impacts leaf morphogenesis and leads to enhanced cold tolerance in rice (Oryza sativa L.).

PubMed

Yang, Chunhua; Li, Dayong; Mao, Donghai; Liu, Xue; Ji, Chengjun; Li, Xiaobing; Zhao, Xianfeng; Cheng, Zhukuan; Chen, Caiyan; Zhu, Lihuang

2013-12-01

MicroRNA319 (miR319) family is one of the conserved microRNA (miRNA) families among diverse plant species. It has been reported that miR319 regulates plant development in dicotyledons, but little is known at present about its functions in monocotyledons. In rice (Oryza sativa L.), the MIR319 gene family comprises two members, Osa-MIR319a and Osa-MIR319b. Here, we report an expression pattern analysis and a functional characterization of the two Osa-MIR319 genes in rice. We found that overexpressing Osa-MIR319a and Osa-MIR319b in rice both resulted in wider leaf blades. Leaves of osa-miR319 overexpression transgenic plants showed an increased number of longitudinal small veins, which probably accounted for the increased leaf blade width. In addition, we observed that overexpressing osa-miR319 led to enhanced cold tolerance (4 °C) after chilling acclimation (12 °C) in transgenic rice seedlings. Notably, under both 4 and 12 °C low temperatures, Osa-MIR319a and Osa-MIR319b were down-regulated while the expression of miR319-targeted genes was induced. Furthermore, genetically down-regulating the expression of either of the two miR319-targeted genes, OsPCF5 and OsPCF8, in RNA interference (RNAi) plants also resulted in enhanced cold tolerance after chilling acclimation. Our findings in this study demonstrate that miR319 plays important roles in leaf morphogenesis and cold tolerance in rice. © 2013 John Wiley & Sons Ltd.

Live imaging of heart tube development in mouse reveals alternating phases of cardiac differentiation and morphogenesis

PubMed Central

Ivanovitch, Kenzo; Temiño, Susana

2017-01-01

During vertebrate heart development, two progenitor populations, first and second heart fields (FHF, SHF), sequentially contribute to longitudinal subdivisions of the heart tube (HT), with the FHF contributing the left ventricle and part of the atria, and the SHF the rest of the heart. Here, we study the dynamics of cardiac differentiation and morphogenesis by tracking individual cells in live analysis of mouse embryos. We report that during an initial phase, FHF precursors differentiate rapidly to form a cardiac crescent, while limited morphogenesis takes place. In a second phase, no differentiation occurs while extensive morphogenesis, including splanchnic mesoderm sliding over the endoderm, results in HT formation. In a third phase, cardiac precursor differentiation resumes and contributes to SHF-derived regions and the dorsal closure of the HT. These results reveal tissue-level coordination between morphogenesis and differentiation during HT formation and provide a new framework to understand heart development. PMID:29202929

The Role of Sonic Hedgehog in Craniofacial Patterning, Morphogenesis and Cranial Neural Crest Survival

PubMed Central

Dworkin, Sebastian; Boglev, Yeliz; Owens, Harley; Goldie, Stephen J.

2016-01-01

Craniofacial defects (CFD) are a significant healthcare problem worldwide. Understanding both the morphogenetic movements which underpin normal facial development, as well as the molecular factors which regulate these processes, forms the cornerstone of future diagnostic, and ultimately, preventative therapies. The soluble morphogen Sonic hedgehog (Shh), a vertebrate orthologue of Drosophila hedgehog, is a key signalling factor in the regulation of craniofacial skeleton development in vertebrates, operating within numerous tissue types in the craniofacial primordia to spatiotemporally regulate the formation of the face and jaws. This review will provide an overview of normal craniofacial skeleton development, and focus specifically on the known roles of Shh in regulating the development and progression of the first pharyngeal arch, which in turn gives rise to both the upper jaw (maxilla) and lower jaw (mandible). PMID:29615588

The Role of Sonic Hedgehog in Craniofacial Patterning, Morphogenesis and Cranial Neural Crest Survival.

PubMed

Dworkin, Sebastian; Boglev, Yeliz; Owens, Harley; Goldie, Stephen J

2016-08-03

Craniofacial defects (CFD) are a significant healthcare problem worldwide. Understanding both the morphogenetic movements which underpin normal facial development, as well as the molecular factors which regulate these processes, forms the cornerstone of future diagnostic, and ultimately, preventative therapies. The soluble morphogen Sonic hedgehog ( Shh ), a vertebrate orthologue of Drosophila hedgehog , is a key signalling factor in the regulation of craniofacial skeleton development in vertebrates, operating within numerous tissue types in the craniofacial primordia to spatiotemporally regulate the formation of the face and jaws. This review will provide an overview of normal craniofacial skeleton development, and focus specifically on the known roles of Shh in regulating the development and progression of the first pharyngeal arch, which in turn gives rise to both the upper jaw (maxilla) and lower jaw (mandible).

VEGF signaling inside vascular endothelial cells and beyond.

PubMed

Eichmann, Anne; Simons, Michael

2012-04-01

Vascular endothelial growth factor-A (VEGF-A) has long been recognized as the key regulator of vascular development and function in health and disease. VEGF is a secreted polypeptide that binds to transmembrane tyrosine kinase VEGF receptors on the plasma membrane, inducing their dimerization, activation and assembly of a membrane-proximal signaling complex. Recent studies have revealed that many key events of VEGFR signaling occur inside the endothelial cell and are regulated by endosomal receptor trafficking. Plasma membrane VEGFR interacting molecules, including vascular guidance receptors Neuropilins and Ephrins also regulate VEGFR endocytosis and trafficking. VEGF signaling is increasingly recognized for its roles outside of the vascular system, notably during neural development, and blood vessels regulate epithelial branching morphogenesis. We review here recent advances in our understanding of VEGF signaling and its biological roles. Copyright © 2012 Elsevier Ltd. All rights reserved.

Asymmetric leaves1 mediates leaf patterning and stem cell function in Arabidopsis.

PubMed

Byrne, M E; Barley, R; Curtis, M; Arroyo, J M; Dunham, M; Hudson, A; Martienssen, R A

Meristem function in plants requires both the maintenance of stem cells and the specification of founder cells from which lateral organs arise. Lateral organs are patterned along proximodistal, dorsoventral and mediolateral axes. Here we show that the Arabidopsis mutant asymmetric leaves1 (as1) disrupts this process. AS1 encodes a myb domain protein, closely related to PHANTASTICA in Antirrhinum and ROUGH SHEATH2 in maize, both of which negatively regulate knotted-class homeobox genes. AS1 negatively regulates the homeobox genes KNAT1 and KNAT2 and is, in turn, negatively regulated by the meristematic homeobox gene SHOOT MERISTEMLESS. This genetic pathway defines a mechanism for differentiating between stem cells and organ founder cells within the shoot apical meristem and demonstrates that genes expressed in organ primordia interact with meristematic genes to regulate shoot morphogenesis.

The canonical Wnt signaling activator, R-spondin2, regulates craniofacial patterning and morphogenesis within the branchial arch through ectodermal-mesenchymal interaction

PubMed Central

Jin, Yong-Ri; Turcotte, Taryn J.; Crocker, Alison L.; Han, Xiang Hua; Yoon, Jeong Kyo

2011-01-01

R-spondins are a recently characterized family of secreted proteins that activate Wnt/β-catenin signaling. Herein, we determine R-spondin2 (Rspo2) function in craniofacial development in mice. Mice lacking a functional Rspo2 gene exhibit craniofacial abnormalities such as mandibular hypoplasia, maxillary and mandibular skeletal deformation, and cleft palate. We found that loss of the mouse Rspo2 gene significantly disrupted Wnt/β-catenin signaling and gene expression within the first branchial arch (BA1). Rspo2, which is normally expressed in BA1 mesenchymal cells, regulates gene expression through a unique ectoderm-mesenchyme interaction loop. The Rspo2 protein, potentially in combination with ectoderm-derived Wnt ligands, up-regulates Msx1 and Msx2 expression within mesenchymal cells. In contrast, Rspo2 regulates expression of the Dlx5, Dlx6, and Hand2 genes in mesenchymal cells via inducing expression of their upstream activator, Endothelin1 (Edn1), within ectodermal cells. Loss of Rspo2 also causes increased cell apoptosis, especially within the aboral (or caudal) domain of the BA1, resulting in hypoplasia of the BA1. Severely reduced expression of Fgf8, a survival factor for mesenchymal cells, in the ectoderm of Rspo2−/− embryos is likely responsible for increased cell apoptosis. Additionally, we found that cleft palate in Rspo2−/− mice is not associated with defects intrinsic to the palatal shelves. A possible cause of cleft palate is a delay of proper palatal shelf elevation that may result from the small mandible and a failure of lowering the tongue. Thus, our study identifies Rspo2 as a mesenchyme-derived factor that plays critical roles in regulating BA1 patterning and morphogenesis through ectodermal-mesenchymal interaction and a novel genetic factor for cleft palate. PMID:21237142

Temporal regulation of epithelium formation mediated by FoxA, MKLP1, MgcRacGAP, and PAR-6

PubMed Central

Von Stetina, Stephen E.; Liang, Jennifer; Marnellos, Georgios; Mango, Susan E.

2017-01-01

To establish the animal body plan, embryos link the external epidermis to the internal digestive tract. In Caenorhabditis elegans, this linkage is achieved by the arcade cells, which form an epithelial bridge between the foregut and epidermis, but little is known about how development of these three epithelia is coordinated temporally. The arcade cell epithelium is generated after the epidermis and digestive tract epithelia have matured, ensuring that both organs can withstand the mechanical stress of embryo elongation; mistiming of epithelium formation leads to defects in morphogenesis. Using a combination of genetic, bioinformatic, and imaging approaches, we find that temporal regulation of the arcade cell epithelium is mediated by the pioneer transcription factor and master regulator PHA-4/FoxA, followed by the cytoskeletal regulator and kinesin ZEN-4/MKLP1 and the polarity protein PAR-6. We show that PHA-4 directly activates mRNA expression of a broad cohort of epithelial genes, including junctional factor dlg-1. Accumulation of DLG-1 protein is delayed by ZEN-4, acting in concert with its binding partner CYK-4/MgcRacGAP. Our structure–function analysis suggests that nuclear and kinesin functions are dispensable, whereas binding to CYK-4 is essential, for ZEN-4 function in polarity. Finally, PAR-6 is necessary to localize polarity proteins such as DLG-1 within adherens junctions and at the apical surface, thereby generating arcade cell polarity. Our results reveal that the timing of a landmark event during embryonic morphogenesis is mediated by the concerted action of four proteins that delay the formation of an epithelial bridge until the appropriate time. In addition, we find that mammalian FoxA associates with many epithelial genes, suggesting that direct regulation of epithelial identity may be a conserved feature of FoxA factors and a contributor to FoxA function in development and cancer. PMID:28539408

Un(MaSC)ing Stem Cell Dynamics in Mammary Branching Morphogenesis.

PubMed

Greenwood, Erin; Wrenn, Emma D; Cheung, Kevin J

2017-02-27

The properties of stem cells that participate in mammary gland branching morphogenesis remain contested. Reporting in Nature, Scheele et al. (2017) establish a model for post-pubertal mammary branching morphogenesis in which position-dependent, lineage-restricted stem cells undergo cell mixing in order to contribute to long-term growth. Copyright © 2017 Elsevier Inc. All rights reserved.

Identification of Sonic Hedgehog-Induced Stromal Factors That Stimulate Prostate Tumor Growth

DTIC Science & Technology

2007-11-01

Regulates Prostate Tumor Growth by a Paracrine Mechanism. Poster at The 4th International Conference on Tumor Microenvironment, Florence, Italy ...transcription in a prostate smooth muscle cell line (PS-1). Endocrinology 137:864-872. Grishina, I.B., Kim, S.Y., Ferrara , C., Makarenkova, H.P., and Walden...Endocrinology 137:864-872. Grishina, I.B., Kim, S.Y., Ferrara , C., Makarenkova, H.P., and Walden, P.D. (2005) BMP7 inhibits branching morphogenesis in the

Development of the cardiac pacemaker

PubMed Central

Liang, Xingqun; Evans, Sylvia M.

2017-01-01

The sinoatrial node (SAN) is the dominant pacemaker of the heart. Abnormalities in SAN formation and function can cause sinus arrhythmia, including sick sinus syndrome and sudden death. A better understanding of genes and signaling pathways that regulate SAN development and function is essential to develop more effective treatment to sinus arrhythmia, including biological pacemakers. In this review, we briefly summarize the key processes of SAN morphogenesis during development, and focus on the transcriptional network that drives SAN development. PMID:27770149

Integrin-extracellular matrix interactions in connective tissue remodeling and osteoblast differentiation

NASA Technical Reports Server (NTRS)

Globus, R. K.; Moursi, A.; Zimmerman, D.; Lull, J.; Damsky, C.

1995-01-01

The differentiaton of bone cells is a complex multistep process. Bone is somewhat unusual in that it is very actively and continually remodeled in the adult and that maintenance of its mass in the mature organism is exquisitely sensitive to mechanical as well as chemical signals. Bone is also unique because it consists of a very large amount of extracellular matrix (ECM) that is mineralized. The integrin family of ECM receptors has been shown to play an important role in tissue morphogenesis in several systems. Our studies on the regulation of matrix remodeling enzymes by integrins in rabbit synovial fibroblasts show that two b1 integrin fibronectin (FN) receptor complexes (alpha 5 beta 1 and alpha 4 beta 1) cooperate in detecting subtle changes in the composition of the ECM. As a result of signal transduction by these integrins, the levels of mRNA and protein for several members of the metalloproteinase family are regulated in these cells. We have also used antibody and RGD peptide perturbation studies to determine the significance of cell/ECM interactions to normal osteogenesis. We found that interactions between the cell binding domain of FN and integrins are required for both normal morphogenesis and gene expression in cultured osteoblasts that differentiate to form bone-like tissue in culture. These data lead us to propose that beta 1 integrins play an important role in osteoblast differentiation as well as in bone remodeling.

The Rap GTPase Activator Drosophila PDZ-GEF Regulates Cell Shape in Epithelial Migration and Morphogenesis▿

PubMed Central

Boettner, Benjamin; Van Aelst, Linda

2007-01-01

Epithelial morphogenesis is characterized by an exquisite control of cell shape and position. Progression through dorsal closure in Drosophila gastrulation depends on the ability of Rap1 GTPase to signal through the adherens junctional multidomain protein Canoe. Here, we provide genetic evidence that epithelial Rap activation and Canoe effector usage are conferred by the Drosophila PDZ-GEF (dPDZ-GEF) exchange factor. We demonstrate that dPDZ-GEF/Rap/Canoe signaling modulates cell shape and apicolateral cell constriction in embryonic and wing disc epithelia. In dPDZ-GEF mutant embryos with strong dorsal closure defects, cells in the lateral ectoderm fail to properly elongate. Postembryonic dPDZ-GEF mutant cells generated in mosaic tissue display a striking extension of lateral cell perimeters in the proximity of junctional complexes, suggesting a loss of normal cell contractility. Furthermore, our data indicate that dPDZ-GEF signaling is linked to myosin II function. Both dPDZ-GEF and cno show strong genetic interactions with the myosin II-encoding gene, and myosin II distribution is severely perturbed in epithelia of both mutants. These findings provide the first insight into the molecular machinery targeted by Rap signaling to modulate epithelial plasticity. We propose that dPDZ-GEF-dependent signaling functions as a rheostat linking Rap activity to the regulation of cell shape in epithelial morphogenesis at different developmental stages. PMID:17846121

Interaction of the receptor FGFRL1 with the negative regulator Spred1.

PubMed

Zhuang, Lei; Villiger, Peter; Trueb, Beat

2011-09-01

FGFRL1 is a member of the fibroblast growth factor receptor family. It plays an essential role during branching morphogenesis of the metanephric kidneys, as mice with a targeted deletion of the Fgfrl1 gene show severe kidney dysplasia. Here we used the yeast two-hybrid system to demonstrate that FGFRL1 binds with its C-terminal, histidine-rich domain to Spred1 and to other proteins of the Sprouty/Spred family. Members of this family are known to act as negative regulators of the Ras/Raf/Erk signaling pathway. Truncation experiments further showed that FGFRL1 interacts with the SPR domain of Spred1, a domain that is shared by all members of the Sprouty/Spred family. The interaction could be verified by coprecipitation of the interaction partners from solution and by codistribution at the cell membrane of COS1 and HEK293 cells. Interestingly, Spred1 increased the retention time of FGFRL1 at the plasma membrane where the receptor might interact with ligands. FGFRL1 and members of the Sprouty/Spred family belong to the FGF synexpression group, which also includes FGF3, FGF8, Sef and Isthmin. It is conceivable that FGFRL1, Sef and some Sprouty/Spred proteins work in concert to control growth factor signaling during branching morphogenesis of the kidneys and other organs. Copyright © 2011 Elsevier Inc. All rights reserved.

ApoA-II directs morphogenetic movements of zebrafish embryo by preventing chromosome fusion during nuclear division in yolk syncytial layer.

PubMed

Zhang, Ting; Yao, Shaohua; Wang, Ping; Yin, Chaoran; Xiao, Chun; Qian, Meilin; Liu, Donghui; Zheng, Lemin; Meng, Wentong; Zhu, Hongyan; Liu, Jin; Xu, Hong; Mo, Xianming

2011-03-18

The high density lipoprotein (HDL) represents a class of lipid- and protein-containing particles and consists of two major apolipoproteins apoA-I and apoA-II. ApoA-II has been shown to be involved in the pathogenesis of insulin resistance, adiposity, diabetes, and metabolic syndrome. In embryo, apoa2 mRNAs are abundant in the liver, brain, lung, placenta, and in fish yolk syncytial layer (YSL), suggesting that apoa2 may perform a function during embryonic development. Here we find out that apoa2 modulates zebrafish embryonic development by regulating the organization of YSL. Disruption of apoa2 function in zebrafish caused chromosome fusing, which strongly blocked YSL nuclear division, inducing disorders in YSL organization and finally disturbing the embryonic epiboly. Purified native human apoA-II was able specifically to rescue the defects and induced nuclear division in zebrafish embryos and in human HeLa cells. The C terminus of apoA-II was required for the proper chromosome separation during nuclear division of YSL in zebrafish embryos and in human HeLa cells. Our data indicate that organization of YSL is required for blastoderm patterning and morphogenesis and suggest that apolipoprotein apoA-II is a novel factor of nuclear division in YSL involved in the regulation of early zebrafish embryonic morphogenesis and in mammalian cells for proliferation.

ApoA-II Directs Morphogenetic Movements of Zebrafish Embryo by Preventing Chromosome Fusion during Nuclear Division in Yolk Syncytial Layer*

PubMed Central

Zhang, Ting; Yao, Shaohua; Wang, Ping; Yin, Chaoran; Xiao, Chun; Qian, Meilin; Liu, Donghui; Zheng, Lemin; Meng, Wentong; Zhu, Hongyan; Liu, Jin; Xu, Hong; Mo, Xianming

2011-01-01

The high density lipoprotein (HDL) represents a class of lipid- and protein-containing particles and consists of two major apolipoproteins apoA-I and apoA-II. ApoA-II has been shown to be involved in the pathogenesis of insulin resistance, adiposity, diabetes, and metabolic syndrome. In embryo, apoa2 mRNAs are abundant in the liver, brain, lung, placenta, and in fish yolk syncytial layer (YSL), suggesting that apoa2 may perform a function during embryonic development. Here we find out that apoa2 modulates zebrafish embryonic development by regulating the organization of YSL. Disruption of apoa2 function in zebrafish caused chromosome fusing, which strongly blocked YSL nuclear division, inducing disorders in YSL organization and finally disturbing the embryonic epiboly. Purified native human apoA-II was able specifically to rescue the defects and induced nuclear division in zebrafish embryos and in human HeLa cells. The C terminus of apoA-II was required for the proper chromosome separation during nuclear division of YSL in zebrafish embryos and in human HeLa cells. Our data indicate that organization of YSL is required for blastoderm patterning and morphogenesis and suggest that apolipoprotein apoA-II is a novel factor of nuclear division in YSL involved in the regulation of early zebrafish embryonic morphogenesis and in mammalian cells for proliferation. PMID:21212265

Regulating temporospatial dynamics of morphogen for structure formation of the lacrimal gland by chitosan biomaterials.

PubMed

Hsiao, Ya-Chuan; Yang, Tsung-Lin

2017-01-01

The lacrimal gland is an important organ responsible for regulating tear synthesis and secretion. The major work of lacrimal gland (LG) is to lubricate the ocular surface and maintain the health of eyes. Functional deterioration of the lacrimal gland happens because of aging, diseases, or therapeutic complications, but without effective treatments till now. The LG originates from the epithelium of ocular surface and develops by branching morphogenesis. To regenerate functional LGs, it is required to explore the way of recapitulating and facilitating the organ to establish the intricate and ramified structure. In this study, we proposed an approach using chitosan biomaterials to create a biomimetic environment beneficial to the branching structure formation of developing LG. The morphogenetic effect of chitosan was specific and optimized to promote LG branching. With chitosan, increase in temporal expression and local concentration of endogenous HGF-related molecules creates an environment around the emerging tip of LG epithelia. By efficiently enhancing downstream signaling of HGF pathways, the cellular activities and behaviors were activated to contribute to LG branching morphogenesis. The morphogenetic effect of chitosan was abolished by either ligand or receptor deprivation, or inhibition of downstream signaling transduction. Our results elucidated the underlying mechanism accounting for chitosan morphogenetic effects on LG, and also proposed promising approaches with chitosan to assist tissue structure formation of the LG. Copyright © 2016 Elsevier Ltd. All rights reserved.

A global regulatory system links virulence and antibiotic resistance to envelope homeostasis in Acinetobacter baumannii.

PubMed

Geisinger, Edward; Mortman, Nadav J; Vargas-Cuebas, Germán; Tai, Albert K; Isberg, Ralph R

2018-05-01

The nosocomial pathogen Acinetobacter baumannii is a significant threat due to its ability to cause infections refractory to a broad range of antibiotic treatments. We show here that a highly conserved sensory-transduction system, BfmRS, mediates the coordinate development of both enhanced virulence and resistance in this microorganism. Hyperactive alleles of BfmRS conferred increased protection from serum complement killing and allowed lethal systemic disease in mice. BfmRS also augmented resistance and tolerance against an expansive set of antibiotics, including dramatic protection from β-lactam toxicity. Through transcriptome profiling, we showed that BfmRS governs these phenotypes through global transcriptional regulation of a post-exponential-phase-like program of gene expression, a key feature of which is modulation of envelope biogenesis and defense pathways. BfmRS activity defended against cell-wall lesions through both β-lactamase-dependent and -independent mechanisms, with the latter being connected to control of lytic transglycosylase production and proper coordination of morphogenesis and division. In addition, hypersensitivity of bfmRS knockouts could be suppressed by unlinked mutations restoring a short, rod cell morphology, indicating that regulation of drug resistance, pathogenicity, and envelope morphogenesis are intimately linked by this central regulatory system in A. baumannii. This work demonstrates that BfmRS controls a global regulatory network coupling cellular physiology to the ability to cause invasive, drug-resistant infections.

Rho2 Palmitoylation Is Required for Plasma Membrane Localization and Proper Signaling to the Fission Yeast Cell Integrity Mitogen-Activated Protein Kinase Pathway

PubMed Central

Sánchez-Mir, Laura; Franco, Alejandro; Martín-García, Rebeca; Madrid, Marisa; Vicente-Soler, Jero; Soto, Teresa; Gacto, Mariano; Pérez, Pilar

2014-01-01

The fission yeast small GTPase Rho2 regulates morphogenesis and is an upstream activator of the cell integrity pathway, whose key element, mitogen-activated protein kinase (MAPK) Pmk1, becomes activated by multiple environmental stimuli and controls several cellular functions. Here we demonstrate that farnesylated Rho2 becomes palmitoylated in vivo at cysteine-196 within its carboxyl end and that this modification allows its specific targeting to the plasma membrane. Unlike that of other palmitoylated and prenylated GTPases, the Rho2 control of morphogenesis and Pmk1 activity is strictly dependent upon plasma membrane localization and is not found in other cellular membranes. Indeed, artificial plasma membrane targeting bypassed the Rho2 need for palmitoylation in order to signal. Detailed functional analysis of Rho2 chimeras fused to the carboxyl end from the essential GTPase Rho1 showed that GTPase palmitoylation is partially dependent on the prenylation context and confirmed that Rho2 signaling is independent of Rho GTP dissociation inhibitor (GDI) function. We further demonstrate that Rho2 is an in vivo substrate for DHHC family acyltransferase Erf2 palmitoyltransferase. Remarkably, Rho3, another Erf2 target, negatively regulates Pmk1 activity in a Rho2-independent fashion, thus revealing the existence of cross talk whereby both GTPases antagonistically modulate the activity of this MAPK cascade. PMID:24820419

Regulation of neurite morphogenesis by interaction between R7 regulator of G protein signaling complexes and G protein subunit Gα13.

PubMed

Scherer, Stephanie L; Cain, Matthew D; Kanai, Stanley M; Kaltenbronn, Kevin M; Blumer, Kendall J

2017-06-16

The R7 regulator of G protein signaling family (R7-RGS) critically regulates nervous system development and function. Mice lacking all R7-RGS subtypes exhibit diverse neurological phenotypes, and humans bearing mutations in the retinal R7-RGS isoform RGS9-1 have vision deficits. Although each R7-RGS subtype forms heterotrimeric complexes with Gβ 5 and R7-RGS-binding protein (R7BP) that regulate G protein-coupled receptor signaling by accelerating deactivation of G i/o α-subunits, several neurological phenotypes of R7-RGS knock-out mice are not readily explained by dysregulated G i/o signaling. Accordingly, we used tandem affinity purification and LC-MS/MS to search for novel proteins that interact with R7-RGS heterotrimers in the mouse brain. Among several proteins detected, we focused on Gα 13 because it had not been linked to R7-RGS complexes before. Split-luciferase complementation assays indicated that Gα 13 in its active or inactive state interacts with R7-RGS heterotrimers containing any R7-RGS isoform. LARG (leukemia-associated Rho guanine nucleotide exchange factor (GEF)), PDZ-RhoGEF, and p115RhoGEF augmented interaction between activated Gα 13 and R7-RGS heterotrimers, indicating that these effector RhoGEFs can engage Gα 13 ·R7-RGS complexes. Because Gα 13 /R7-RGS interaction required R7BP, we analyzed phenotypes of neuronal cell lines expressing RGS7 and Gβ 5 with or without R7BP. We found that neurite retraction evoked by Gα 12/13 -dependent lysophosphatidic acid receptors was augmented in R7BP-expressing cells. R7BP expression blunted neurite formation evoked by serum starvation by signaling mechanisms involving Gα 12/13 but not Gα i/o These findings provide the first evidence that R7-RGS heterotrimers interact with Gα 13 to augment signaling pathways that regulate neurite morphogenesis. This mechanism expands the diversity of functions whereby R7-RGS complexes regulate critical aspects of nervous system development and function. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Requirement of Phosphoinositides Containing Stearic Acid To Control Cell Polarity.

PubMed

Doignon, François; Laquel, Patricia; Testet, Eric; Tuphile, Karine; Fouillen, Laetitia; Bessoule, Jean-Jacques

2015-12-28

Phosphoinositides (PIPs) are present in very small amounts but are essential for cell signaling, morphogenesis, and polarity. By mass spectrometry, we demonstrated that some PIPs with stearic acyl chains were strongly disturbed in a psi1Δ Saccharomyces cerevisiae yeast strain deficient in the specific incorporation of a stearoyl chain at the sn-1 position of phosphatidylinositol. The absence of PIPs containing stearic acid induced disturbances in intracellular trafficking, although the total amount of PIPs was not diminished. Changes in PIPs also induced alterations in the budding pattern and defects in actin cytoskeleton organization (cables and patches). Moreover, when the PSI1 gene was impaired, a high proportion of cells with bipolar cortical actin patches that occurred concomitantly with the bipolar localization of Cdc42p was specifically found among diploid cells. This bipolar cortical actin phenotype, never previously described, was also detected in a bud9Δ/bud9Δ strain. Very interestingly, overexpression of PSI1 reversed this phenotype. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Computational Modeling of Morphogenesis Regulated by Mechanical Feedback

PubMed Central

Ramasubramanian, Ashok; Taber, Larry A.

2008-01-01

Mechanical forces cause changes in form during embryogenesis and likely play a role in regulating these changes. This paper explores the idea that changes in homeostatic tissue stress (target stress), possibly modulated by genes, drive some morphogenetic processes. Computational models are presented to illustrate how regional variations in target stress can cause a range of complex behaviors involving the bending of epithelia. These models include growth and cytoskeletal contraction regulated by stress-based mechanical feedback. All simulations were carried out using the commercial finite element code ABAQUS, with growth and contraction included by modifying the zero-stress state in the material constitutive relations. Results presented for bending of bilayered beams and invagination of cylindrical and spherical shells provide insight into some of the mechanical aspects that must be considered in studying morphogenetic mechanisms. PMID:17318485

Remodelling the extracellular matrix in development and disease

PubMed Central

Bonnans, Caroline; Chou, Jonathan; Werb, Zena

2015-01-01

The extracellular matrix (ECM) is a highly dynamic structure that is present in all tissues and continuously undergoes controlled remodelling. This process involves quantitative and qualitative changes in the ECM, mediated by specific enzymes that are responsible for ECM degradation, such as metalloproteinases. The ECM interacts with cells to regulate diverse functions, including proliferation, migration and differentiation. ECM remodelling is crucial for regulating the morphogenesis of the intestine and lungs, as well as of the mammary and submandibular glands. Dysregulation of ECM composition, structure, stiffness and abundance contributes to several pathological conditions, such as fibrosis and invasive cancer. A better understanding of how the ECM regulates organ structure and function and of how ECM remodelling affects disease progression will contribute to the development of new therapeutics. PMID:25415508

36th Annual David W. Smith Workshop on Malformations and Morphogenesis: Abstracts of the 2015 annual meeting.

PubMed

Gripp, Karen W; Adam, Margaret P; Hudgins, Louanne; Carey, John C

2016-07-01

The 36th Annual David W Smith Workshop on Malformations and Morphogenesis was held on August 14-19, 2015 at the Harbourtowne Conference Center in St. Michaels Maryland. The Workshop, which honors the legacy of David W Smith, brought together over 120 clinicians and researchers interested in congenital malformations and their underlying mechanisms of morphogenesis. As is the tradition of the meeting, the Workshop highlighted five themes besides mechanisms of morphogenesis: Rasopathies, Eye Malformations, Therapeutics, Prenatal Diagnosis, and Disorders of Sex Development. This Conference Report includes the abstracts presented at the 2015 Workshop. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Extracellular matrix motion and early morphogenesis

PubMed Central

Loganathan, Rajprasad; Rongish, Brenda J.; Smith, Christopher M.; Filla, Michael B.; Czirok, Andras; Bénazéraf, Bertrand

2016-01-01

For over a century, embryologists who studied cellular motion in early amniotes generally assumed that morphogenetic movement reflected migration relative to a static extracellular matrix (ECM) scaffold. However, as we discuss in this Review, recent investigations reveal that the ECM is also moving during morphogenesis. Time-lapse studies show how convective tissue displacement patterns, as visualized by ECM markers, contribute to morphogenesis and organogenesis. Computational image analysis distinguishes between cell-autonomous (active) displacements and convection caused by large-scale (composite) tissue movements. Modern quantification of large-scale ‘total’ cellular motion and the accompanying ECM motion in the embryo demonstrates that a dynamic ECM is required for generation of the emergent motion patterns that drive amniote morphogenesis. PMID:27302396

Bacteriophage prevalence in the genus Azospirillum and analysis of the first genome sequence of an Azospirillum brasilense integrative phage.

PubMed

Boyer, Mickaël; Haurat, Jacqueline; Samain, Sylvie; Segurens, Béatrice; Gavory, Frédérick; González, Víctor; Mavingui, Patrick; Rohr, René; Bally, René; Wisniewski-Dyé, Florence

2008-02-01

The prevalence of bacteriophages was investigated in 24 strains of four species of plant growth-promoting rhizobacteria belonging to the genus Azospirillum. Upon induction by mitomycin C, the release of phage particles was observed in 11 strains from three species. Transmission electron microscopy revealed two distinct sizes of particles, depending on the identity of the Azospirillum species, typical of the Siphoviridae family. Pulsed-field gel electrophoresis and hybridization experiments carried out on phage-encapsidated DNAs revealed that all phages isolated from A. lipoferum and A. doebereinerae strains had a size of about 10 kb whereas all phages isolated from A. brasilense strains displayed genome sizes ranging from 62 to 65 kb. Strong DNA hybridizing signals were shown for most phages hosted by the same species whereas no homology was found between phages harbored by different species. Moreover, the complete sequence of the A. brasilense Cd bacteriophage (phiAb-Cd) genome was determined as a double-stranded DNA circular molecule of 62,337 pb that encodes 95 predicted proteins. Only 14 of the predicted proteins could be assigned functions, some of which were involved in DNA processing, phage morphogenesis, and bacterial lysis. In addition, the phiAb-Cd complete genome was mapped as a prophage on a 570-kb replicon of strain A. brasilense Cd, and a region of 27.3 kb of phiAb-Cd was found to be duplicated on the 130-kb pRhico plasmid previously sequenced from A. brasilense Sp7, the parental strain of A. brasilense Cd.

Bacteriophage Prevalence in the Genus Azospirillum and Analysis of the First Genome Sequence of an Azospirillum brasilense Integrative Phage▿

PubMed Central

Boyer, Mickaël; Haurat, Jacqueline; Samain, Sylvie; Segurens, Béatrice; Gavory, Frédérick; González, Víctor; Mavingui, Patrick; Rohr, René; Bally, René; Wisniewski-Dyé, Florence

2008-01-01

The prevalence of bacteriophages was investigated in 24 strains of four species of plant growth-promoting rhizobacteria belonging to the genus Azospirillum. Upon induction by mitomycin C, the release of phage particles was observed in 11 strains from three species. Transmission electron microscopy revealed two distinct sizes of particles, depending on the identity of the Azospirillum species, typical of the Siphoviridae family. Pulsed-field gel electrophoresis and hybridization experiments carried out on phage-encapsidated DNAs revealed that all phages isolated from A. lipoferum and A. doebereinerae strains had a size of about 10 kb whereas all phages isolated from A. brasilense strains displayed genome sizes ranging from 62 to 65 kb. Strong DNA hybridizing signals were shown for most phages hosted by the same species whereas no homology was found between phages harbored by different species. Moreover, the complete sequence of the A. brasilense Cd bacteriophage (ΦAb-Cd) genome was determined as a double-stranded DNA circular molecule of 62,337 pb that encodes 95 predicted proteins. Only 14 of the predicted proteins could be assigned functions, some of which were involved in DNA processing, phage morphogenesis, and bacterial lysis. In addition, the ΦAb-Cd complete genome was mapped as a prophage on a 570-kb replicon of strain A. brasilense Cd, and a region of 27.3 kb of ΦAb-Cd was found to be duplicated on the 130-kb pRhico plasmid previously sequenced from A. brasilense Sp7, the parental strain of A. brasilense Cd. PMID:18065619

Morphogenesis and Biomechanics of Engineered Skin Cultured Under Uniaxial Strain

PubMed Central

Blackstone, Britani N.; Powell, Heather M.

2012-01-01

Background Split-thickness autograft is the standard wound treatment for full-thickness burns. In large burns, sparse availability of uninjured skin prevents rapid closure of the wound, resulting in increased scar tissue formation or mortality. Tissue-engineered skin (ES) offers promise when autografts are not available. The Problem ES, constructed from a polymeric scaffold and skin cells, has been shown to reduce donor site area required to permanently close wounds, mortality, and morbidity from scarring but cannot restore all skin functions. Current generations of ES are orders of magnitude weaker than normal human skin, leading to difficulty in surgical application, greater susceptibility to mechanical damage during fabrication and application, and less elasticity and strength once engrafted. Basic/Clinical Science Advances Previous studies to improve ES biomechanics focus on altering the scaffolding material, which resulted in modest improvements but often inhibited proper skin development. As the skin is naturally under static strain, adding these mechanical cues to the culture environment is hypothesized to improve ES biomechanics. ES was cultured under applied static strains ranging from 0% to 40% strain for a total of 10 days. Strain magnitudes of 10% and 20% strain resulted in significantly stronger ES than unstrained controls, showed upregulation of many genes encoding structural extracellular matrix proteins, and exhibited increased epidermal cell proliferation and differentiation. Clinical Care Relevance Enhanced biomechanical properties of ES can allow for facile surgical application and less damage during dressing changes. Conclusion These findings suggest that mechanical cues play a significant role in skin development and should be further explored. PMID:24527283

Stromal–epithelial cell interactions and alteration of branching morphogenesis in macromastic mammary glands

PubMed Central

Zhong, Aimei; Wang, Guohua; Yang, Jie; Xu, Qijun; Yuan, Quan; Yang, Yanqing; Xia, Yun; Guo, Ke; Horch, Raymund E; Sun, Jiaming

2014-01-01

True macromastia is a rare but disabling condition characterized by massive breast growth. The aetiology and pathogenic mechanisms for this disorder remain largely unexplored because of the lack of in vivo or in vitro models. Previous studies suggested that regulation of epithelial cell growth and development by oestrogen was dependent on paracrine growth factors from the stroma. In this study, a co-culture model containing epithelial and stromal cells was used to investigate the interactions of these cells in macromastia. Epithelial cell proliferation and branching morphogenesis were measured to assess the effect of macromastic stromal cells on epithelial cells. We analysed the cytokines secreted by stromal cells and identified molecules that were critical for effects on epithelial cells. Our results indicated a significant increase in cell proliferation and branching morphogenesis of macromastic and non-macromastic epithelial cells when co-cultured with macromastic stromal cells or in conditioned medium from macromastic stromal cells. Hepatocyte growth factor (HGF) is a key factor in epithelial–stromal interactions of macromastia-derived cell cultures. Blockade of HGF with neutralizing antibodies dramatically attenuated epithelial cell proliferation in conditioned medium from macromastic stromal cells. The epithelial–stromal cell co-culture model demonstrated reliability for studying interactions of mammary stromal and epithelial cells in macromastia. In this model, HGF secreted by macromastic stromal cells was found to play an important role in modifying the behaviour of co-cultured epithelial cells. This model allows further studies to investigate basic cellular and molecular mechanisms in tissue from patients with true breast hypertrophy. PMID:24720804

Turing mechanism underlying a branching model for lung morphogenesis.

PubMed

Xu, Hui; Sun, Mingzhu; Zhao, Xin

2017-01-01

The mammalian lung develops through branching morphogenesis. Two primary forms of branching, which occur in order, in the lung have been identified: tip bifurcation and side branching. However, the mechanisms of lung branching morphogenesis remain to be explored. In our previous study, a biological mechanism was presented for lung branching pattern formation through a branching model. Here, we provide a mathematical mechanism underlying the branching patterns. By decoupling the branching model, we demonstrated the existence of Turing instability. We performed Turing instability analysis to reveal the mathematical mechanism of the branching patterns. Our simulation results show that the Turing patterns underlying the branching patterns are spot patterns that exhibit high local morphogen concentration. The high local morphogen concentration induces the growth of branching. Furthermore, we found that the sparse spot patterns underlie the tip bifurcation patterns, while the dense spot patterns underlies the side branching patterns. The dispersion relation analysis shows that the Turing wavelength affects the branching structure. As the wavelength decreases, the spot patterns change from sparse to dense, the rate of tip bifurcation decreases and side branching eventually occurs instead. In the process of transformation, there may exists hybrid branching that mixes tip bifurcation and side branching. Since experimental studies have reported that branching mode switching from side branching to tip bifurcation in the lung is under genetic control, our simulation results suggest that genes control the switch of the branching mode by regulating the Turing wavelength. Our results provide a novel insight into and understanding of the formation of branching patterns in the lung and other biological systems.

Foxi3 deficiency compromises hair follicle stem cell specification and activation

PubMed Central

Shirokova, Vera; Biggs, Leah C.; Jussila, Maria; Ohyama, Takahiro; Groves, Andrew K.; Mikkola, Marja L.

2017-01-01

The hair follicle is an ideal system to study stem cell specification and homeostasis due to its well characterized morphogenesis and stereotypic cycles of stem cell activation upon each hair cycle to produce a new hair shaft. The adult hair follicle stem cell niche consists of two distinct populations, the bulge and the more activation-prone secondary hair germ. Hair follicle stem cells are set aside during early stages of morphogenesis. This process is known to depend on the Sox9 transcription factor, but otherwise the establishment of the hair follicle stem cell niche is poorly understood. Here we show that that mutation of Foxi3, a Forkhead family transcription factor mutated in several hairless dog breeds, compromises stem cell specification. Further, loss of Foxi3 impedes hair follicle downgrowth and progression of the hair cycle. Genome-wide profiling revealed a number of downstream effectors of Foxi3 including transcription factors with a recognized function in hair follicle stem cells such as Lhx2, Runx1, and Nfatc1, suggesting that the Foxi3 mutant phenotype results from simultaneous downregulation of several stem cell signature genes. We show that Foxi3 displays a highly dynamic expression pattern during hair morphogenesis and cycling, and identify Foxi3 as a novel secondary hair germ marker. Absence of Foxi3 results in poor hair regeneration upon hair plucking, and a sparse fur phenotype in unperturbed mice that exacerbates with age, caused by impaired secondary hair germ activation leading to progressive depletion of stem cells. Thus, Foxi3 regulates multiple aspects of hair follicle development and homeostasis. PMID:26992132

Ectopic expression of Msx-2 in posterior limb bud mesoderm impairs limb morphogenesis while inducing BMP-4 expression, inhibiting cell proliferation, and promoting apoptosis.

PubMed

Ferrari, D; Lichtler, A C; Pan, Z Z; Dealy, C N; Upholt, W B; Kosher, R A

1998-05-01

During early stages of chick limb development, the homeobox-containing gene Msx-2 is expressed in the mesoderm at the anterior margin of the limb bud and in a discrete group of mesodermal cells at the midproximal posterior margin. These domains of Msx-2 expression roughly demarcate the anterior and posterior boundaries of the progress zone, the highly proliferating posterior mesodermal cells underneath the apical ectodermal ridge (AER) that give rise to the skeletal elements of the limb and associated structures. Later in development as the AER loses its activity, Msx-2 expression expands into the distal mesoderm and subsequently into the interdigital mesenchyme which demarcates the developing digits. The domains of Msx-2 expression exhibit considerably less proliferation than the cells of the progress zone and also encompass several regions of programmed cell death including the anterior and posterior necrotic zones and interdigital mesenchyme. We have thus suggested that Msx-2 may be in a regulatory network that delimits the progress zone by suppressing the morphogenesis of the regions of the limb mesoderm in which it is highly expressed. In the present study we show that ectopic expression of Msx-2 via a retroviral expression vector in the posterior mesoderm of the progress zone from the time of initial formation of the limb bud severely impairs limb morphogenesis. Msx-2-infected limbs are typically very narrow along the anteroposterior axis, are occasionally truncated, and exhibit alterations in the pattern of formation of skeletal elements, indicating that as a consequence of ectopic Msx-2 expression the morphogenesis of large portions of the posterior mesoderm has been suppressed. We further show that Msx-2 impairs limb morphogenesis by reducing cell proliferation and promoting apoptosis in the regions of the posterior mesoderm in which it is ectopically expressed. The domains of ectopic Msx-2 expression in the posterior mesoderm also exhibit ectopic expression of BMP-4, a secreted signaling molecule that is coexpressed with Msx-2 during normal limb development in the anterior limb mesoderm, the posterior necrotic zone, and interdigital mesenchyme. This indicates that Msx-2 regulates BMP-4 expression and that the suppressive effects of Msx-2 on limb morphogenesis might be mediated in part by BMP-4. These studies indicate that during normal limb development Msx-2 is a key component of a regulatory network that delimits the boundaries of the progress zone by suppressing the morphogenesis of the regions of the limb mesoderm in which it is highly expressed, thus restricting the outgrowth and formation of skeletal elements and associated structures to the progress zone. We also report that rather large numbers of apoptotic cells as well as proliferating cells are present throughout the AER during all stages of normal limb development we have examined, indicating that many of the cells of the AER are continuously undergoing programmed cell death at the same time that new AER cells are being generated by cell proliferation. Thus, a balance between cell proliferation and programmed cell death may play a very important role in maintaining the activity of the AER. Copyright 1998 Academic Press.

Active cell-matrix coupling regulates cellular force landscapes of cohesive epithelial monolayers

NASA Astrophysics Data System (ADS)

Zhao, Tiankai; Zhang, Yao; Wei, Qiong; Shi, Xuechen; Zhao, Peng; Chen, Long-Qing; Zhang, Sulin

2018-03-01

Epithelial cells can assemble into cohesive monolayers with rich morphologies on substrates due to competition between elastic, edge, and interfacial effects. Here we present a molecularly based thermodynamic model, integrating monolayer and substrate elasticity, and force-mediated focal adhesion formation, to elucidate the active biochemical regulation over the cellular force landscapes in cohesive epithelial monolayers, corroborated by microscopy and immunofluorescence studies. The predicted extracellular traction and intercellular tension are both monolayer size and substrate stiffness dependent, suggestive of cross-talks between intercellular and extracellular activities. Our model sets a firm ground toward a versatile computational framework to uncover the molecular origins of morphogenesis and disease in multicellular epithelia.

The fungus Ustilago maydis, from the aztec cuisine to the research laboratory.

PubMed

Ruiz-Herrera, J; Martínez-Espinoza, A D

1998-06-01

Ustilago maydis is a plant pathogen fungus responsible for corn smut. It has a complex life cycle. In its saprophitic stage, it grows as haploid yeast cells, while in the invasive stage it grows as a mycelium formed by diploid cells. Thus, a correlation exists between genetic ploidy, pathogenicity and morphogenesis. Dimorphism can be modulated in vitro by changing environmental parameters such as pH. Studies with auxotrophic mutants have shown that polyamines play a central role in regulating dimorphism. Molecular biology approaches are being employed for the analysis of fundamental aspects of the biology of this fungus, such as mating type regulation, dimorphism or cell wall biogenesis.

Role of citron kinase in dendritic morphogenesis of cortical neurons.

PubMed

Di Cunto, Ferdinando; Ferrara, Luciana; Curtetti, Roberta; Imarisio, Sara; Guazzone, Simona; Broccoli, Vania; Bulfone, Alessandro; Altruda, Fiorella; Vercelli, Alessandro; Silengo, Lorenzo

2003-05-30

Small GTPases of the rho family regulate the extensive rearrangements of the cytoskeleton that characterize neuronal differentiation. Citron kinase is a target molecule for activated rhoA, previously implicated in control of cytokinesis. We have found that, in addition, it could play an important role in modulating the extension of neuronal processes. Using constitutively active and dominant negative mutants, we showed that citron kinase is involved in the morphologic differentiation of N1E-115 neuroblastoma cells induced by serum starvation. More importantly, quantitative analysis of citron kinase knockout cerebral cortex displayed that this molecule may differentially regulate the morphology of the dendritic compartment in corticocollicular versus callosally-projecting pyramidal neurons.

The Ets transcription factor Elf5 specifies mammary alveolar cell fate

PubMed Central

Oakes, Samantha R.; Naylor, Matthew J.; Asselin-Labat, Marie-Liesse; Blazek, Katrina D.; Gardiner-Garden, Margaret; Hilton, Heidi N.; Kazlauskas, Michael; Pritchard, Melanie A.; Chodosh, Lewis A.; Pfeffer, Peter L.; Lindeman, Geoffrey J.; Visvader, Jane E.; Ormandy, Christopher J.

2008-01-01

Hormonal cues regulate mammary development, but the consequent transcriptional changes and cell fate decisions are largely undefined. We show that knockout of the prolactin-regulated Ets transcription factor Elf5 prevented formation of the secretory epithelium during pregnancy. Conversely, overexpression of Elf5 in an inducible transgenic model caused alveolar differentiation and milk secretion in virgin mice, disrupting ductal morphogenesis. CD61+ luminal progenitor cells accumulated in Elf5-deficient mammary glands and were diminished in glands with Elf5 overexpression. Thus Elf5 specifies the differentiation of CD61+ progenitors to establish the secretory alveolar lineage during pregnancy, providing a link between prolactin, transcriptional events, and alveolar development. PMID:18316476

Histone methylations in heart development, congenital and adult heart diseases.

PubMed

Zhang, Qing-Jun; Liu, Zhi-Ping

2015-01-01

Heart development comprises myocyte specification, differentiation and cardiac morphogenesis. These processes are regulated by a group of core cardiac transcription factors in a coordinated temporal and spatial manner. Histone methylation is an emerging epigenetic mechanism for regulating gene transcription. Interplay among cardiac transcription factors and histone lysine modifiers plays important role in heart development. Aberrant expression and mutation of the histone lysine modifiers during development and in adult life can cause either embryonic lethality or congenital heart diseases, and influences the response of adult hearts to pathological stresses. In this review, we describe current body of literature on the role of several common histone methylations and their modifying enzymes in heart development, congenital and adult heart diseases.

Patterned cortical tension mediated by N-cadherin controls cell geometric order in the Drosophila eye

PubMed Central

Chan, Eunice HoYee; Chavadimane Shivakumar, Pruthvi; Clément, Raphaël; Laugier, Edith; Lenne, Pierre-François

2017-01-01

Adhesion molecules hold cells together but also couple cell membranes to a contractile actomyosin network, which limits the expansion of cell contacts. Despite their fundamental role in tissue morphogenesis and tissue homeostasis, how adhesion molecules control cell shapes and cell patterns in tissues remains unclear. Here we address this question in vivo using the Drosophila eye. We show that cone cell shapes depend little on adhesion bonds and mostly on contractile forces. However, N-cadherin has an indirect control on cell shape. At homotypic contacts, junctional N-cadherin bonds downregulate Myosin-II contractility. At heterotypic contacts with E-cadherin, unbound N-cadherin induces an asymmetric accumulation of Myosin-II, which leads to a highly contractile cell interface. Such differential regulation of contractility is essential for morphogenesis as loss of N-cadherin disrupts cell rearrangements. Our results establish a quantitative link between adhesion and contractility and reveal an unprecedented role of N-cadherin on cell shapes and cell arrangements. DOI: http://dx.doi.org/10.7554/eLife.22796.001 PMID:28537220

Comparative inner ear transcriptome analysis between the Rickett's big-footed bats (Myotis ricketti) and the greater short-nosed fruit bats (Cynopterus sphinx).

PubMed

Dong, Dong; Lei, Ming; Liu, Yang; Zhang, Shuyi

2013-12-23

Bats have aroused great interests of researchers for the sake of their advanced echolocation system. However, this highly specialized trait is not characteristic of Old World fruit bats. To comprehensively explore the underlying molecular basis between echolocating and non-echolocating bats, we employed a sequence-based approach to compare the inner ear expression difference between the Rickett's big-footed bat (Myotis ricketti, echolocating bat) and the Greater short-nosed fruit bat (Cynopterus sphinx, non-echolocating bat). De novo sequence assemblies were developed for both species. The results showed that the biological implications of up-regulated genes in M. ricketti were significantly over-represented in biological process categories such as 'cochlea morphogenesis', 'inner ear morphogenesis' and 'sensory perception of sound', which are consistent with the inner ear morphological and physiological differentiation between the two bat species. Moreover, the expression of TMC1 gene confirmed its important function in echolocating bats. Our work presents the first transcriptome comparison between echolocating and non-echolocating bats, and provides information about the genetic basis of their distinct hearing traits.

The tumor suppressor PTEN and the PDK1 kinase regulate formation of the columnar neural epithelium

PubMed Central

Grego-Bessa, Joaquim; Bloomekatz, Joshua; Castel, Pau; Omelchenko, Tatiana; Baselga, José; Anderson, Kathryn V

2016-01-01

Epithelial morphogenesis and stability are essential for normal development and organ homeostasis. The mouse neural plate is a cuboidal epithelium that remodels into a columnar pseudostratified epithelium over the course of 24 hr. Here we show that the transition to a columnar epithelium fails in mutant embryos that lack the tumor suppressor PTEN, although proliferation, patterning and apical-basal polarity markers are normal in the mutants. The Pten phenotype is mimicked by constitutive activation of PI3 kinase and is rescued by the removal of PDK1 (PDPK1), but does not depend on the downstream kinases AKT and mTORC1. High resolution imaging shows that PTEN is required for stabilization of planar cell packing in the neural plate and for the formation of stable apical-basal microtubule arrays. The data suggest that appropriate levels of membrane-associated PDPK1 are required for stabilization of apical junctions, which promotes cell elongation, during epithelial morphogenesis. DOI: http://dx.doi.org/10.7554/eLife.12034.001 PMID:26809587

Mechanical control of notochord morphogenesis by extra-embryonic tissues in mouse embryos.

PubMed

Imuta, Yu; Koyama, Hiroshi; Shi, Dongbo; Eiraku, Mototsugu; Fujimori, Toshihiko; Sasaki, Hiroshi

2014-05-01

Mammalian embryos develop in coordination with extraembryonic tissues, which support embryonic development by implanting embryos into the uterus, supplying nutrition, providing a confined niche, and also providing patterning signals to embryos. Here, we show that in mouse embryos, the expansion of the amniotic cavity (AC), which is formed between embryonic and extraembryonic tissues, provides the mechanical forces required for a type of morphogenetic movement of the notochord known as convergent extension (CE) in which the cells converge to the midline and the tissue elongates along the antero-posterior (AP) axis. The notochord is stretched along the AP axis, and the expansion of the AC is required for CE. Both mathematical modeling and physical simulation showed that a rectangular morphology of the early notochord caused the application of anisotropic force along the AP axis to the notochord through the isotropic expansion of the AC. AC expansion acts upstream of planar cell polarity (PCP) signaling, which regulates CE movement. Our results highlight the importance of extraembryonic tissues as a source of the forces that control the morphogenesis of embryos. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

MpWIP regulates air pore complex development in the liverwort Marchantia polymorpha

PubMed Central

Jones, Victor A. S.

2017-01-01

The colonisation of the land by plants was accompanied by the evolution of complex tissues and multicellular structures comprising different cell types as morphological adaptations to the terrestrial environment. Here, we show that the single WIP protein in the early-diverging land plant Marchantia polymorpha L. is required for the development of the multicellular gas exchange structure: the air pore complex. This 16-cell barrel-shaped structure surrounds an opening between epidermal cells that facilitates the exchange of gases between the chamber containing the photosynthetic cells inside the plant and the air outside. MpWIP is expressed in cells of the developing air pore complex and the morphogenesis of the complex is defective in plants with reduced MpWIP function. The role of WIP proteins in the control of different multicellular structures in M. polymorpha and the flowering plant Arabidopsis thaliana suggests that these proteins controlled the development of multicellular structures in the common ancestor of land plants. We hypothesise that WIP genes were subsequently co-opted in the control of morphogenesis of novel multicellular structures that evolved during the diversification of land plants. PMID:28174248

Endometrial Expression of Steroidogenic Factor 1 Promotes Cystic Glandular Morphogenesis

PubMed Central

Vasquez, Yasmin M.; Wu, San-Pin; Anderson, Matthew L.; Hawkins, Shannon M.; Creighton, Chad J.; Ray, Madhumita; Tsai, Sophia Y.; Tsai, Ming-Jer; Lydon, John P.

2016-01-01

Epigenetic silencing of steroidogenic factor 1 (SF1) is lost in endometriosis, potentially contributing to de novo local steroidogenesis favoring inflammation and growth of ectopic endometrial tissue. In this study, we examine the impact of SF1 expression in the eutopic uterus by a novel mouse model that conditionally expresses SF1 in endometrium. In vivo SF1 expression promoted the development of enlarged endometrial glands and attenuated estrogen and progesterone responsiveness. Endometriosis induction by autotransplantation of uterine tissue to the mesenteric membrane resulted in the increase in size of ectopic lesions from SF1-expressing mice. By integrating the SF1-dependent transcriptome with the whole genome binding profile of SF1, we identified uterine-specific SF1-regulated genes involved in Wingless and Progesterone receptor-Hedgehog-Chicken ovalbumin upstream promoter transcription factor II signaling for gland development and epithelium-stroma interaction, respectively. The present results indicate that SF1 directly contributes to the abnormal uterine gland morphogenesis, an inhibition of steroid hormone signaling and activation of an immune response, in addition to previously postulated estrogen production. PMID:27018534

CNS Macrophages Control Neurovascular Development via CD95L.

PubMed

Chen, Si; Tisch, Nathalie; Kegel, Marcel; Yerbes, Rosario; Hermann, Robert; Hudalla, Hannes; Zuliani, Cecilia; Gülcüler, Gülce Sila; Zwadlo, Klara; von Engelhardt, Jakob; Ruiz de Almodóvar, Carmen; Martin-Villalba, Ana

2017-05-16

The development of neurons and vessels shares striking anatomical and molecular features, and it is presumably orchestrated by an overlapping repertoire of extracellular signals. CNS macrophages have been implicated in various developmental functions, including the morphogenesis of neurons and vessels. However, whether CNS macrophages can coordinately influence neurovascular development and the identity of the signals involved therein is unclear. Here, we demonstrate that activity of the cell surface receptor CD95 regulates neuronal and vascular morphogenesis in the post-natal brain and retina. Furthermore, we identify CNS macrophages as the main source of CD95L, and macrophage-specific deletion thereof reduces both neurovascular complexity and synaptic activity in the brain. CD95L-induced neuronal and vascular growth is mediated through src-family kinase (SFK) and PI3K signaling. Together, our study highlights a coordinated neurovascular development instructed by CNS macrophage-derived CD95L, and it underlines the importance of macrophages for the establishment of the neurovascular network during CNS development. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Spatial control of translation repression and polarized growth by conserved NDR kinase Orb6 and RNA-binding protein Sts5.

PubMed

Nuñez, Illyce; Rodriguez Pino, Marbelys; Wiley, David J; Das, Maitreyi E; Chen, Chuan; Goshima, Tetsuya; Kume, Kazunori; Hirata, Dai; Toda, Takashi; Verde, Fulvia

2016-07-30

RNA-binding proteins contribute to the formation of ribonucleoprotein (RNP) granules by phase transition, but regulatory mechanisms are not fully understood. Conserved fission yeast NDR (Nuclear Dbf2-Related) kinase Orb6 governs cell morphogenesis in part by spatially controlling Cdc42 GTPase. Here we describe a novel, independent function for Orb6 kinase in negatively regulating the recruitment of RNA-binding protein Sts5 into RNPs to promote polarized cell growth. We find that Orb6 kinase inhibits Sts5 recruitment into granules, its association with processing (P) bodies, and degradation of Sts5-bound mRNAs by promoting Sts5 interaction with 14-3-3 protein Rad24. Many Sts5-bound mRNAs encode essential factors for polarized cell growth, and Orb6 kinase spatially and temporally controls the extent of Sts5 granule formation. Disruption of this control system affects cell morphology and alters the pattern of polarized cell growth, revealing a role for Orb6 kinase in the spatial control of translational repression that enables normal cell morphogenesis.

Integrating high-throughput genetic interaction mapping and high-content screening to explore yeast spindle morphogenesis

PubMed Central

Vizeacoumar, Franco J.; van Dyk, Nydia; S.Vizeacoumar, Frederick; Cheung, Vincent; Li, Jingjing; Sydorskyy, Yaroslav; Case, Nicolle; Li, Zhijian; Datti, Alessandro; Nislow, Corey; Raught, Brian; Zhang, Zhaolei; Frey, Brendan; Bloom, Kerry

2010-01-01

We describe the application of a novel screening approach that combines automated yeast genetics, synthetic genetic array (SGA) analysis, and a high-content screening (HCS) system to examine mitotic spindle morphogenesis. We measured numerous spindle and cellular morphological parameters in thousands of single mutants and corresponding sensitized double mutants lacking genes known to be involved in spindle function. We focused on a subset of genes that appear to define a highly conserved mitotic spindle disassembly pathway, which is known to involve Ipl1p, the yeast aurora B kinase, as well as the cell cycle regulatory networks mitotic exit network (MEN) and fourteen early anaphase release (FEAR). We also dissected the function of the kinetochore protein Mcm21p, showing that sumoylation of Mcm21p regulates the enrichment of Ipl1p and other chromosomal passenger proteins to the spindle midzone to mediate spindle disassembly. Although we focused on spindle disassembly in a proof-of-principle study, our integrated HCS-SGA method can be applied to virtually any pathway, making it a powerful means for identifying specific cellular functions. PMID:20065090

MET receptor tyrosine kinase controls dendritic complexity, spine morphogenesis, and glutamatergic synapse maturation in the hippocampus.

PubMed

Qiu, Shenfeng; Lu, Zhongming; Levitt, Pat

2014-12-03

The MET receptor tyrosine kinase (RTK), implicated in risk for autism spectrum disorder (ASD) and in functional and structural circuit integrity in humans, is a temporally and spatially regulated receptor enriched in dorsal pallial-derived structures during mouse forebrain development. Here we report that loss or gain of function of MET in vitro or in vivo leads to changes, opposite in nature, in dendritic complexity, spine morphogenesis, and the timing of glutamatergic synapse maturation onto hippocampus CA1 neurons. Consistent with the morphological and biochemical changes, deletion of Met in mutant mice results in precocious maturation of excitatory synapse, as indicated by a reduction of the proportion of silent synapses, a faster GluN2A subunit switch, and an enhanced acquisition of AMPA receptors at synaptic sites. Thus, MET-mediated signaling appears to serve as a mechanism for controlling the timing of neuronal growth and functional maturation. These studies suggest that mistimed maturation of glutamatergic synapses leads to the aberrant neural circuits that may be associated with ASD risk. Copyright © 2014 the authors 0270-6474/14/3416166-14$15.00/0.

MET Receptor Tyrosine Kinase Controls Dendritic Complexity, Spine Morphogenesis, and Glutamatergic Synapse Maturation in the Hippocampus

PubMed Central

Lu, Zhongming; Levitt, Pat

2014-01-01

The MET receptor tyrosine kinase (RTK), implicated in risk for autism spectrum disorder (ASD) and in functional and structural circuit integrity in humans, is a temporally and spatially regulated receptor enriched in dorsal pallial-derived structures during mouse forebrain development. Here we report that loss or gain of function of MET in vitro or in vivo leads to changes, opposite in nature, in dendritic complexity, spine morphogenesis, and the timing of glutamatergic synapse maturation onto hippocampus CA1 neurons. Consistent with the morphological and biochemical changes, deletion of Met in mutant mice results in precocious maturation of excitatory synapse, as indicated by a reduction of the proportion of silent synapses, a faster GluN2A subunit switch, and an enhanced acquisition of AMPA receptors at synaptic sites. Thus, MET-mediated signaling appears to serve as a mechanism for controlling the timing of neuronal growth and functional maturation. These studies suggest that mistimed maturation of glutamatergic synapses leads to the aberrant neural circuits that may be associated with ASD risk. PMID:25471559

Cdc42 and formin activity control non-muscle myosin dynamics during Drosophila heart morphogenesis

PubMed Central

Vogler, Georg; Liu, Jiandong; Iafe, Timothy W.; Migh, Ede; Mihály, József

2014-01-01

During heart formation, a network of transcription factors and signaling pathways guide cardiac cell fate and differentiation, but the genetic mechanisms orchestrating heart assembly and lumen formation remain unclear. Here, we show that the small GTPase Cdc42 is essential for Drosophila melanogaster heart morphogenesis and lumen formation. Cdc42 genetically interacts with the cardiogenic transcription factor tinman; with dDAAM which belongs to the family of actin organizing formins; and with zipper, which encodes nonmuscle myosin II. Zipper is required for heart lumen formation, and its spatiotemporal activity at the prospective luminal surface is controlled by Cdc42. Heart-specific expression of activated Cdc42, or the regulatory formins dDAAM and Diaphanous caused mislocalization of Zipper and induced ectopic heart lumina, as characterized by luminal markers such as the extracellular matrix protein Slit. Placement of Slit at the lumen surface depends on Cdc42 and formin function. Thus, Cdc42 and formins play pivotal roles in heart lumen formation through the spatiotemporal regulation of the actomyosin network. PMID:25267295

PPFIA1 drives active α5β1 integrin recycling and controls fibronectin fibrillogenesis and vascular morphogenesis

PubMed Central

Mana, Giulia; Clapero, Fabiana; Panieri, Emiliano; Panero, Valentina; Böttcher, Ralph T.; Tseng, Hui-Yuan; Saltarin, Federico; Astanina, Elena; Wolanska, Katarzyna I.; Morgan, Mark R.; Humphries, Martin J.; Santoro, Massimo M.; Serini, Guido; Valdembri, Donatella

2016-01-01

Basolateral polymerization of cellular fibronectin (FN) into a meshwork drives endothelial cell (EC) polarity and vascular remodelling. However, mechanisms coordinating α5β1 integrin-mediated extracellular FN endocytosis and exocytosis of newly synthesized FN remain elusive. Here we show that, on Rab21-elicited internalization, FN-bound/active α5β1 is recycled to the EC surface. We identify a pathway, comprising the regulators of post-Golgi carrier formation PI4KB and AP-1A, the small GTPase Rab11B, the surface tyrosine phosphatase receptor PTPRF and its adaptor PPFIA1, which we propose acts as a funnel combining FN secretion and recycling of active α5β1 integrin from the trans-Golgi network (TGN) to the EC surface, thus allowing FN fibrillogenesis. In this framework, PPFIA1 interacts with active α5β1 integrin and localizes close to EC adhesions where post-Golgi carriers are targeted. We show that PPFIA1 is required for FN polymerization-dependent vascular morphogenesis, both in vitro and in the developing zebrafish embryo. PMID:27876801

Foxp1 Regulates Cortical Radial Migration and Neuronal Morphogenesis in Developing Cerebral Cortex

PubMed Central

Li, Xue; Xiao, Jian; Fröhlich, Henning; Tu, Xiaomeng; Li, Lianlian; Xu, Yue; Cao, Huateng; Qu, Jia; Rappold, Gudrun A.; Chen, Jie-Guang

2015-01-01

FOXP1 is a member of FOXP subfamily transcription factors. Mutations in FOXP1 gene have been found in various development-related cognitive disorders. However, little is known about the etiology of these symptoms, and specifically the function of FOXP1 in neuronal development. Here, we report that suppression of Foxp1 expression in mouse cerebral cortex led to a neuronal migration defect, which was rescued by overexpression of Foxp1. Mice with Foxp1 knockdown exhibited ectopic neurons in deep layers of the cortex postnatally. The neuronal differentiation of Foxp1-downregulated cells was normal. However, morphological analysis showed that the neurons with Foxp1 deficiency had an inhibited axonal growth in vitro and a weakened transition from multipolar to bipolar in vivo. Moreover, we found that the expression of Foxp1 modulated the dendritic maturation of neurons at a late postnatal date. Our results demonstrate critical roles of Foxp1 in the radial migration and morphogenesis of cortical neurons during development. This study may shed light on the complex relationship between neuronal development and the related cognitive disorders. PMID:26010426

BAF200 is required for heart morphogenesis and coronary artery development.

PubMed

He, Lingjuan; Tian, Xueying; Zhang, Hui; Hu, Tianyuan; Huang, Xiuzhen; Zhang, Libo; Wang, Zhong; Zhou, Bin

2014-01-01

ATP-dependent SWI/SNF chromatin remodeling complexes utilize ATP hydrolysis to non-covalently change nucleosome-DNA interactions and are essential in stem cell development, organogenesis, and tumorigenesis. Biochemical studies show that SWI/SNF in mammalian cells can be divided into two subcomplexes BAF and PBAF based on the subunit composition. ARID2 or BAF200 has been defined as an intrinsic subunit of PBAF complex. However, the function of BAF200 in vivo is not clear. To dissect the possible role of BAF200 in regulating embryogenesis and organ development, we generated BAF200 mutant mice and found they were embryonic lethal. BAF200 mutant embryos exhibited multiple cardiac defects including thin myocardium, ventricular septum defect, common atrioventricular valve, and double outlet right ventricle around E14.5. Moreover, we also detected reduced intramyocardial coronary arteries in BAF200 mutants, suggesting that BAF200 is required for proper migration and differentiation of subepicardial venous cells into arterial endothelial cells. Our work revealed that PBAF complex plays a critical role in heart morphogenesis and coronary artery angiogenesis.

Expression of Genes Involved in Drosophila Wing Morphogenesis and Vein Patterning Are Altered by Spaceflight

NASA Technical Reports Server (NTRS)

Parsons-Wingerter, Patricia A.; Hosamani, Ravikumar; Bhattacharya, Sharmila

2015-01-01

Imaginal wing discs of Drosophila melanogaster (fruit fly) defined during embryogenesis ultimately result in mature wings of stereotyped (specific) venation patterning. Major regulators of wing disc development are the epidermal growth factor receptor (EGF), Notch, Hedgehog (Hh), Wingless (Wg), and Dpp signaling pathways. Highly stereotyped vascular patterning is also characteristic of tissues in other organisms flown in space such as the mouse retina and leaves of Arabidopsis thaliana. Genetic and other adaptations of vascular patterning to space environmental factors have not yet been systematically quantified, despite widespread recognition of their critical importance for terrestrial and microgravity applications. Here we report changes in gene expression with space flight related to Drosophila wing morphogenesis and vein patterning. In addition, genetically modified phenotypes of increasingly abnormal ectopic wing venation in the Drosophila wing1 were analyzed by NASA's VESsel GENeration Analysis (VESGEN) software2. Our goal is to further develop insightful vascular mappings associated with bioinformatic dimensions of genetic or other molecular phenotypes for correlation with genetic and other molecular profiling relevant to NASA's GeneLab and other Space Biology exploration initiatives.

EMMPRIN (basigin/CD147) is involved in the morphogenesis of tooth germ in mouse molars.

PubMed

Xie, Ming; Jiao, Ting; Chen, Yuqin; Xu, Chun; Li, Jing; Jiang, Xinquan; Zhang, Fuqiang

2010-05-01

The pattern of gene expression for extracellular matrix metalloproteinase inducer (EMMPRIN) was revealed in the tooth germ of mouse mandibular molars using quantitative real-time PCR. In situ hybridization and immunohistochemical study demonstrated the characteristic distribution of EMMPRIN in the different stages of tooth germ development. To investigate the functional role played by EMMPRIN in tooth germ development, EMMPRIN siRNA interference approach was carried out in cultured mouse mandibles at embryonic day 11.0 (E11.0). The results showed that EMMPRIN siRNA-treated explants exhibited a marked growth inhibition of tooth germ compared to the control and scrambled siRNA-treated explants. Meanwhile, a significant increase in MT1-MMP mRNA expression and a reduction in MMP-2, MMP-3, MMP-9, MMP-13 and MT2-MMP mRNA expression were observed in the mouse mandibles following EMMPRIN abrogation. The current results indicate that EMMPRIN could thus be involved in the early stage of tooth germ development and morphogenesis, possibly by regulating the expression of MMP genes.

Extracellular matrix motion and early morphogenesis.

PubMed

Loganathan, Rajprasad; Rongish, Brenda J; Smith, Christopher M; Filla, Michael B; Czirok, Andras; Bénazéraf, Bertrand; Little, Charles D

2016-06-15

For over a century, embryologists who studied cellular motion in early amniotes generally assumed that morphogenetic movement reflected migration relative to a static extracellular matrix (ECM) scaffold. However, as we discuss in this Review, recent investigations reveal that the ECM is also moving during morphogenesis. Time-lapse studies show how convective tissue displacement patterns, as visualized by ECM markers, contribute to morphogenesis and organogenesis. Computational image analysis distinguishes between cell-autonomous (active) displacements and convection caused by large-scale (composite) tissue movements. Modern quantification of large-scale 'total' cellular motion and the accompanying ECM motion in the embryo demonstrates that a dynamic ECM is required for generation of the emergent motion patterns that drive amniote morphogenesis. © 2016. Published by The Company of Biologists Ltd.

Analysis of maternal-zygotic ugdh mutants reveals divergent roles for HSPGs in vertebrate embryogenesis and provides new insight into the initiation of left-right asymmetry.

PubMed

Superina, Simone; Borovina, Antonia; Ciruna, Brian

2014-03-15

Growth factors and morphogens regulate embryonic patterning, cell fate specification, cell migration, and morphogenesis. The activity and behavior of these signaling molecules are regulated in the extracellular space through interactions with proteoglycans (Bernfield et al., 1999; Perrimon and Bernfield 2000; Lander and Selleck 2000; Selleck 2000). Proteoglycans are high molecular-weight proteins consisting of a core protein with covalently linked glycosaminoglycan (GAG) side chains, which are thought to mediate ligand interaction. Drosophila mutant embryos deficient for UDP-glucose dehydrogenase activity (Ugdh, required for GAG synthesis) exhibit abnormal Fgf, Wnt and TGFß signaling and die during gastrulation, indicating a broad and critical role for proteoglycans during early embryonic development (Lin et al., 1999; Lin and Perrimon 2000) (Hacker et al., 1997). Mouse Ugdh mutants also die at gastrulation, however, only Fgf signaling appears disrupted (Garcia-Garcia and Anderson, 2003). These findings suggested a possible divergence in the requirement for proteoglycans during Drosophila and mouse embryogenesis, and that mammals may have evolved alternative means of regulating Wnt and TGFß activity. To further examine the function of proteoglycans in vertebrate development, we have characterized zebrafish mutants devoid of both maternal and zygotic Ugdh/Jekyll activity (MZjekyll). We demonstrate that MZjekyll mutant embryos display abnormal Fgf, Shh, and Wnt signaling activities, with concomitant defects in central nervous system patterning, cardiac ventricular fate specification and axial morphogenesis. Furthermore, we uncover a novel role for proteoglycans in left-right pattern formation. Our findings resolve longstanding questions into the evolutionary conservation of Ugdh function and provide new mechanistic insights into the initiation of left-right asymmetry. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Regulation of mouse lung development by the extracellular calcium-sensing receptor, CaR

PubMed Central

Finney, Brenda A; del Moral, Pierre M; Wilkinson, William J; Cayzac, Sebastien; Cole, Martin; Warburton, David; Kemp, Paul J; Riccardi, Daniela

2008-01-01

Postnatal lung function is critically dependent upon optimal embryonic lung development. As the free ionized plasma calcium concentration ([Ca2+]o) of the fetus is higher than that of the adult, the process of lung development occurs in a hypercalcaemic environment. In the adult, [Ca2+]o is monitored by the G-protein coupled, extracellular calcium-sensing receptor (CaR), but neither its ontogeny nor its potential role in lung development are known. Here, we demonstrate that CaR is expressed in the mouse lung epithelium, and that its expression is developmentally regulated, with a peak of expression at embryonic day 12.5 (E12.5) and a subsequent decrease by E18, after which the receptor is absent. Experiments carried out using the lung explant culture model in vitro show that lung branching morphogenesis is sensitive to [Ca2+]o, being maximal at physiological adult [Ca2+]o (i.e. 1.0–1.3 mm) and lowest at the higher, fetal (i.e. 1.7 mm) [Ca2+]o. Administration of the specific CaR positive allosteric modulator, the calcimimetic R-568, mimics the suppressive effects of high [Ca2+]o on branching morphogenesis while both phospholipase C and PI3 kinase inhibition reverse these effects. CaR activation suppresses cell proliferation while it enhances intracellular calcium signalling, lung distension and fluid secretion. Conditions which are restrictive either to branching or to secretion can be rescued by manipulating [Ca2+]o in the culture medium. In conclusion, fetal Cao2+, acting through a developmentally regulated CaR, is an important extrinsic factor that modulates the intrinsic lung developmental programme. Our observations support a novel role for the CaR in preventing hyperplastic lung disease in utero. PMID:18955379

Ovule identity mediated by pre-mRNA processing in Arabidopsis

PubMed Central

Rodríguez-Cazorla, Encarnación; Candela, Héctor; Bailey-Steinitz, Lindsay J.; Yanofsky, Martin F.; Martínez-Laborda, Antonio

2018-01-01

Ovules are fundamental for plant reproduction and crop yield as they are the precursors of seeds. Therefore, ovule specification is a critical developmental program. In Arabidopsis thaliana, ovule identity is redundantly conferred by the homeotic D-class genes SHATTERPROOF1 (SHP1), SHP2 and SEEDSTICK (STK), phylogenetically related to the MADS-domain regulatory gene AGAMOUS (AG), essential in floral organ specification. Previous studies have shown that the HUA-PEP activity, comprised of a suite of RNA-binding protein (RBP) encoding genes, regulates AG pre-mRNA processing and thus flower patterning and organ identity. Here, we report that the HUA-PEP activity additionally governs ovule morphogenesis. Accordingly, in severe hua-pep backgrounds ovules transform into flower organ-like structures. These homeotic transformations are most likely due to the dramatic reduction in SHP1, SHP2 and STK activity. Our molecular and genome-wide profiling strategies revealed the accumulation of prematurely terminated transcripts of D-class genes in hua-pep mutants and reduced amounts of their respective functional messengers, which points to pre-mRNA processing misregulation as the origin of the ovule developmental defects in such backgrounds. RNA processing and transcription are coordinated by the RNA polymerase II (RNAPII) carboxyl-terminal domain (CTD). Our results show that HUA-PEP activity members can interact with the CTD regulator C-TERMINAL DOMAIN PHOSPHATASE-LIKE1 (CPL1), supporting a co-transcriptional mode of action for the HUA-PEP activity. Our findings expand the portfolio of reproductive developmental programs in which HUA-PEP activity participates, and further substantiates the importance of RNA regulatory mechanisms (pre-mRNA co-transcriptional regulation) for correct gene expression during plant morphogenesis. PMID:29329291

Dynamic localization of MreB in Vibrio parahaemolyticus and in the ectopic host bacterium Escherichia coli.

PubMed

Chiu, Shen-Wen; Chen, Shau-Yan; Wong, Hin-chung

2008-11-01

MreB, a homolog of eukaryotic actin, participates in morphogenesis, cell division, cell polarity, and chromosome segregation in prokaryotes. In this study, a yellow fluorescent protein conjugate (YFP-MreB(Vp)) was generated to investigate the behavior of MreB in merodiploid strain SC9 of the enteropathogen Vibrio parahaemolyticus. Under normal growth conditions, YFP-MreB(Vp) formed helical filaments with a pitch of 0.64 +/- 0.09 microm in about 85% of exponential-phase cells, and different clusters, relaxed coils, and ring configurations were observed in a small proportion of the cells. Overexpression of YFP-MreB(Vp) substantially altered the structure of the MreB cytoskeleton and resulted in swollen and pleomorphic cells. Disturbing the activities of penicillin-binding proteins or adding magnesium suppressed the morphological distortions. These results indicate that mislocalization of cell wall-synthesizing machinery was responsible for morphological abnormality. By expressing YFP-MreB(Vp) in the ectopic host bacterium Escherichia coli, shrinkage, fragmentation, and annealing of MreB(Vp) filaments were directly observed. This work revealed the dynamic pattern of the localization of YFP-MreB(Vp) in V. parahaemolyticus and its relationship to cell morphogenesis, and the YFP-MreB(Vp)-E. coli system may be used to investigate the dynamic spatial structures of the MreB cytoskeleton in vivo.

The MET13 Methylenetetrahydrofolate Reductase Gene Is Essential for Infection-Related Morphogenesis in the Rice Blast Fungus Magnaporthe oryzae

PubMed Central

Wang, Hong; Wang, Congcong; Li, Ya; Yue, Xiaofeng; Ma, Zhonghua; Talbot, Nicholas J.; Wang, Zhengyi

2013-01-01

Methylenetetrahydrofolate reductases (MTHFRs) play a key role in the biosynthesis of methionine in both prokaryotic and eukaryotic organisms. In this study, we report the identification of a novel T-DNA-tagged mutant WH672 in the rice blast fungus Magnaporthe oryzae, which was defective in vegetative growth, conidiation and pathogenicity. Analysis of the mutation confirmed a single T-DNA insertion upstream of MET13, which encodes a 626-amino-acid protein encoding a MTHFR. Targeted gene deletion of MET13 resulted in mutants that were non-pathogenic and significantly impaired in aerial growth and melanin pigmentation. All phenotypes associated with Δmet13 mutants could be overcome by addition of exogenous methionine. The M. oryzae genome contains a second predicted MTHFR-encoding gene, MET12. The deduced amino acid sequences of Met13 and Met12 share 32% identity. Interestingly, Δmet12 mutants produced significantly less conidia compared with the isogenic wild-type strain and grew very poorly in the absence of methionine, but were fully pathogenic. Deletion of both genes resulted in Δmet13Δmet12 mutants that showed similar phenotypes to single Δmet13 mutants. Taken together, we conclude that the MTHFR gene, MET13, is essential for infection-related morphogenesis by the rice blast fungus M. oryzae. PMID:24116181

Distinct roles of cell wall biogenesis in yeast morphogenesis as revealed by multivariate analysis of high-dimensional morphometric data

PubMed Central

Okada, Hiroki; Ohnuki, Shinsuke; Roncero, Cesar; Konopka, James B.; Ohya, Yoshikazu

2014-01-01

The cell wall of budding yeast is a rigid structure composed of multiple components. To thoroughly understand its involvement in morphogenesis, we used the image analysis software CalMorph to quantitatively analyze cell morphology after treatment with drugs that inhibit different processes during cell wall synthesis. Cells treated with cell wall–affecting drugs exhibited broader necks and increased morphological variation. Tunicamycin, which inhibits the initial step of N-glycosylation of cell wall mannoproteins, induced morphologies similar to those of strains defective in α-mannosylation. The chitin synthase inhibitor nikkomycin Z induced morphological changes similar to those of mutants defective in chitin transglycosylase, possibly due to the critical role of chitin in anchoring the β-glucan network. To define the mode of action of echinocandin B, a 1,3-β-glucan synthase inhibitor, we compared the morphology it induced with mutants of Fks1 that contains the catalytic domain for 1,3-β-glucan synthesis. Echinocandin B exerted morphological effects similar to those observed in some fks1 mutants, with defects in cell polarity and reduced glucan synthesis activity, suggesting that echinocandin B affects not only 1,3-β-glucan synthesis, but also another functional domain. Thus our multivariate analyses reveal discrete functions of cell wall components and increase our understanding of the pharmacology of antifungal drugs. PMID:24258022

A global sensitivity analysis approach for morphogenesis models.

PubMed

Boas, Sonja E M; Navarro Jimenez, Maria I; Merks, Roeland M H; Blom, Joke G

2015-11-21

Morphogenesis is a developmental process in which cells organize into shapes and patterns. Complex, non-linear and multi-factorial models with images as output are commonly used to study morphogenesis. It is difficult to understand the relation between the uncertainty in the input and the output of such 'black-box' models, giving rise to the need for sensitivity analysis tools. In this paper, we introduce a workflow for a global sensitivity analysis approach to study the impact of single parameters and the interactions between them on the output of morphogenesis models. To demonstrate the workflow, we used a published, well-studied model of vascular morphogenesis. The parameters of this cellular Potts model (CPM) represent cell properties and behaviors that drive the mechanisms of angiogenic sprouting. The global sensitivity analysis correctly identified the dominant parameters in the model, consistent with previous studies. Additionally, the analysis provided information on the relative impact of single parameters and of interactions between them. This is very relevant because interactions of parameters impede the experimental verification of the predicted effect of single parameters. The parameter interactions, although of low impact, provided also new insights in the mechanisms of in silico sprouting. Finally, the analysis indicated that the model could be reduced by one parameter. We propose global sensitivity analysis as an alternative approach to study the mechanisms of morphogenesis. Comparison of the ranking of the impact of the model parameters to knowledge derived from experimental data and from manipulation experiments can help to falsify models and to find the operand mechanisms in morphogenesis. The workflow is applicable to all 'black-box' models, including high-throughput in vitro models in which output measures are affected by a set of experimental perturbations.

Extracellular matrix and growth factors in branching morphogenesis

NASA Technical Reports Server (NTRS)

Hardman, P.; Spooner, B. S.

1993-01-01

The unifying hypothesis of the NSCORT in gravitational biology postulates that the ECM and growth factors are key interrelated components of a macromolecular regulatory system. The ECM is known to be important in growth and branching morphogenesis of embryonic organs. Growth factors have been detected in the developing embryo, and often the pattern of localization is associated with areas undergoing epithelial-mesenchymal interactions. Causal relationships between these components may be of fundamental importance in control of branching morphogenesis.

Characterization of the genome of the dairy Lactobacillus helveticus bacteriophage {Phi}AQ113.

PubMed

Zago, Miriam; Scaltriti, Erika; Rossetti, Lia; Guffanti, Alessandro; Armiento, Angelarita; Fornasari, Maria Emanuela; Grolli, Stefano; Carminati, Domenico; Brini, Elena; Pavan, Paolo; Felsani, Armando; D'Urzo, Annalisa; Moles, Anna; Claude, Jean-Baptiste; Grandori, Rita; Ramoni, Roberto; Giraffa, Giorgio

2013-08-01

The complete genomic sequence of the dairy Lactobacillus helveticus bacteriophage ΦAQ113 was determined. Phage ΦAQ113 is a Myoviridae bacteriophage with an isometric capsid and a contractile tail. The final assembled consensus sequence revealed a linear, circularly permuted, double-stranded DNA genome with a size of 36,566 bp and a G+C content of 37%. Fifty-six open reading frames (ORFs) were predicted, and a putative function was assigned to approximately 90% of them. The ΦAQ113 genome shows functionally related genes clustered together in a genome structure composed of modules for DNA replication/regulation, DNA packaging, head and tail morphogenesis, cell lysis, and lysogeny. The identification of genes involved in the establishment of lysogeny indicates that it may have originated as a temperate phage, even if it was isolated from natural cheese whey starters as a virulent phage, because it is able to propagate in a sensitive host strain. Additionally, we discovered that the ΦAQ113 phage genome is closely related to Lactobacillus gasseri phage KC5a and Lactobacillus johnsonii phage Lj771 genomes. The phylogenetic similarities between L. helveticus phage ΦAQ113 and two phages that belong to gut species confirm a possible common ancestral origin and support the increasing consideration of L. helveticus as a health-promoting organism.

Characterization of the Genome of the Dairy Lactobacillus helveticus Bacteriophage ΦAQ113

PubMed Central

Scaltriti, Erika; Rossetti, Lia; Guffanti, Alessandro; Armiento, Angelarita; Fornasari, Maria Emanuela; Grolli, Stefano; Carminati, Domenico; Brini, Elena; Pavan, Paolo; Felsani, Armando; D'Urzo, Annalisa; Moles, Anna; Claude, Jean-Baptiste; Grandori, Rita; Ramoni, Roberto; Giraffa, Giorgio

2013-01-01

The complete genomic sequence of the dairy Lactobacillus helveticus bacteriophage ΦAQ113 was determined. Phage ΦAQ113 is a Myoviridae bacteriophage with an isometric capsid and a contractile tail. The final assembled consensus sequence revealed a linear, circularly permuted, double-stranded DNA genome with a size of 36,566 bp and a G+C content of 37%. Fifty-six open reading frames (ORFs) were predicted, and a putative function was assigned to approximately 90% of them. The ΦAQ113 genome shows functionally related genes clustered together in a genome structure composed of modules for DNA replication/regulation, DNA packaging, head and tail morphogenesis, cell lysis, and lysogeny. The identification of genes involved in the establishment of lysogeny indicates that it may have originated as a temperate phage, even if it was isolated from natural cheese whey starters as a virulent phage, because it is able to propagate in a sensitive host strain. Additionally, we discovered that the ΦAQ113 phage genome is closely related to Lactobacillus gasseri phage KC5a and Lactobacillus johnsonii phage Lj771 genomes. The phylogenetic similarities between L. helveticus phage ΦAQ113 and two phages that belong to gut species confirm a possible common ancestral origin and support the increasing consideration of L. helveticus as a health-promoting organism. PMID:23728811

Determinants of Swe1p Degradation in Saccharomyces cerevisiae

PubMed Central

McMillan, John N.; Theesfeld, Chandra L.; Harrison, Jacob C.; Bardes, Elaine S. G.; Lew, Daniel J.

2002-01-01

Swe1p, the sole Wee1-family kinase in Saccharomyces cerevisiae, is synthesized during late G1 and is then degraded as cells proceed through the cell cycle. However, Swe1p degradation is halted by the morphogenesis checkpoint, which responds to insults that perturb bud formation. The Swe1p stabilization promotes cell cycle arrest through Swe1p-mediated inhibitory phosphorylation of Cdc28p until the cells can recover from the perturbation and resume bud formation. Swe1p degradation involves the relocalization of Swe1p from the nucleus to the mother-bud neck, and neck targeting requires the Swe1p-interacting protein Hsl7p. In addition, Swe1p degradation is stimulated by its substrate, cyclin/Cdc28p, and Swe1p is thought to be a target of the ubiquitin ligase SCFMet30 acting with the ubiquitin-conjugating enzyme Cdc34p. The basis for regulation of Swe1p degradation by the morphogenesis checkpoint remains unclear, and in order to elucidate that regulation we have dissected the Swe1p degradation pathway in more detail, yielding several novel findings. First, we show here that Met30p (and by implication SCFMet30) is not, in fact, required for Swe1p degradation. Second, cyclin/Cdc28p does not influence Swe1p neck targeting, but can directly phosphorylate Swe1p, suggesting that it acts downstream of neck targeting in the Swe1p degradation pathway. Third, a screen for functional but nondegradable mutants of SWE1 identified two small regions of Swe1p that are key to its degradation. One of these regions mediates interaction of Swe1p with Hsl7p, showing that the Swe1p-Hsl7p interaction is critical for Swe1p neck targeting and degradation. The other region did not appear to affect interactions with known Swe1p regulators, suggesting that other as-yet-unknown regulators exist. PMID:12388757

Role of epimorphin in bile duct formation of rat liver epithelial stem-like cells: involvement of small G protein RhoA and C/EBPβ.

PubMed

Jia, Yali; Yao, Hailei; Zhou, Junnian; Chen, Lin; Zeng, Quan; Yuan, Hongfeng; Shi, Lei; Nan, Xue; Wang, Yunfang; Yue, Wen; Pei, Xuetao

2011-11-01

Epimorphin/syntaxin 2 is a high conserved and very abundant protein involved in epithelial morphogenesis in various organs. We have shown recently that epimorphin (EPM), a protein exclusively expressed on the surface of hepatic stellate cells and myofibroblasts of the liver, induces bile duct formation of hepatic stem-like cells (WB-F344 cells) in a putative biophysical way. Therefore, the aim of this study was to present some of the molecular mechanisms by which EPM mediates bile duct formation. We established a biliary differentiation model by co-culture of EPM-overexpressed mesenchymal cells (PT67(EPM)) with WB-F344 cells. Here, we showed that EPM could promote WB-F344 cells differentiation into bile duct-like structures. Biliary differentiation markers were also elevated by EPM including Yp, Cx43, aquaporin-1, CK19, and gamma glutamyl transpeptidase (GGT). Moreover, the signaling pathway of EPM was analyzed by focal adhesion kinase (FAK), extracellular regulated kinase 1/2 (ERK1/2), and RhoA Western blot. Also, a dominant negative (DN) RhoA-WB-F344 cell line (WB(RhoA-DN)) was constructed. We found that the levels of phosphorylation (p) of FAK and ERK1/2 were up-regulated by EPM. Most importantly, we also showed that RhoA is necessary for EPM-induced activation of FAK and ERK1/2 and bile duct formation. In addition, a dual luciferase-reporter assay and CHIP assay was performed to reveal that EPM regulates GGT IV and GGT V expression differentially, possibly mediated by C/EBPβ. Taken together, these data demonstrated that EPM regulates bile duct formation of WB-F344 cells through effects on RhoA and C/EBPβ, implicating a dual aspect of this morphoregulator in bile duct epithelial morphogenesis. Copyright © 2011 Wiley-Liss, Inc.

Sarm1 deficiency impairs synaptic function and leads to behavioral deficits, which can be ameliorated by an mGluR allosteric modulator.

PubMed

Lin, Chia-Wen; Chen, Chiung-Ya; Cheng, Sin-Jhong; Hu, Hsiao-Tang; Hsueh, Yi-Ping

2014-01-01

Innate immune responses have been shown to influence brain development and function. Dysregulation of innate immunity is significantly associated with psychiatric disorders such as autism spectrum disorders and schizophrenia, which are well-known neurodevelopmental disorders. Recent studies have revealed that critical players of the innate immune response are expressed in neuronal tissues and regulate neuronal function and activity. For example, Sarm1, a negative regulator that acts downstream of Toll-like receptor (TLR) 3 and 4, is predominantly expressed in neurons. We have previously shown that Sarm1 regulates neuronal morphogenesis and the expression of inflammatory cytokines in the brain, which then affects learning ability, cognitive flexibility, and social interaction. Because impaired neuronal morphogenesis and dysregulation of cytokine expression may disrupt neuronal activity, we investigated whether Sarm1 knockdown affects the synaptic responses of neurons. We here show that reduced Sarm1 expression impairs metabotropic glutamate receptor (mGluR)-dependent long-term depression (LTD) formation but enhances N-methyl-D-aspartate receptor (NMDAR)-dependent long-term potentiation production in hippocampal CA1 neurons. The expression levels of post-synaptic proteins, including NR2a, NR1, Shank1 and Shank3, are also altered in Sarm1 knockdown mice, suggesting a role for Sarm1 in the maintenance of synaptic homeostasis. The addition of a positive allosteric modulator of mGluR5, CDPPB, ameliorates the LTD defects in slice recording and the behavioral deficits in social interaction and associative memory. These results suggest an important role for mGluR5 signaling in the function of Sarm1. In conclusion, our study demonstrates a role for Sarm1 in the regulation of synaptic plasticity. Through these mechanisms, Sarm1 knockdown results in the impairment of associative memory and social interactions in mice.

Cell confinement controls centrosome positioning and lumen initiation during epithelial morphogenesis

PubMed Central

Rodríguez-Fraticelli, Alejo E.; Auzan, Muriel; Alonso, Miguel A.; Bornens, Michel

2012-01-01

Epithelial organ morphogenesis involves sequential acquisition of apicobasal polarity by epithelial cells and development of a functional lumen. In vivo, cells perceive signals from components of the extracellular matrix (ECM), such as laminin and collagens, as well as sense physical conditions, such as matrix stiffness and cell confinement. Alteration of the mechanical properties of the ECM has been shown to promote cell migration and invasion in cancer cells, but the effects on epithelial morphogenesis have not been characterized. We analyzed the effects of cell confinement on lumen morphogenesis using a novel, micropatterned, three-dimensional (3D) Madin-Darby canine kidney cell culture method. We show that cell confinement, by controlling cell spreading, limits peripheral actin contractility and promotes centrosome positioning and lumen initiation after the first cell division. In addition, peripheral actin contractility is mediated by master kinase Par-4/LKB1 via the RhoA–Rho kinase–myosin II pathway, and inhibition of this pathway restores lumen initiation in minimally confined cells. We conclude that cell confinement controls nuclear–centrosomal orientation and lumen initiation during 3D epithelial morphogenesis. PMID:22965908

Rac1 GTPase -deficient mouse lens exhibits defects in shape, suture formation, fiber cell migration and survival

PubMed Central

Maddala, Rupalatha; Chauhan, Bharesh K.; Walker, Christopher; Zheng, Yi; Robinson, Michael L.; Lang, Richard A.; Rao, Ponugoti V.

2011-01-01

Morphogenesis and shape of the ocular lens depend on epithelial cell elongation and differentiation into fiber cells, followed by the symmetric and compact organization of fiber cells within an enclosed extracellular matrix-enriched elastic capsule. The cellular mechanisms orchestrating these different events however, remain obscure. We investigated the role of the Rac1 GTPase in these processes by targeted deletion of expression using the conditional gene knockout (cKO) approach. Rac1 cKO mice were derived from two different Cre (Le-Cre and MLR-10) transgenic mice in which lens-specific Cre expression starts at embryonic day 8.75 and 10.5, respectively, in both the lens epithelium and fiber cells. The Le-Cre/Rac1 cKO mice exhibited an early-onset (E12.5) and severe lens phenotype compared to the MLR-10/Rac1 cKO (E15.5) mice. While the Le-Cre/Rac1 cKO lenses displayed delayed primary fiber cell elongation, lenses from both Rac1 cKO strains were characterized by abnormal shape, impaired secondary fiber cell migration, sutural defects and thinning of the posterior capsule which often led to rupture. Lens fiber cell N-cadherin/β-catenin/Rap1/Nectin-based cell-cell junction formation and WAVE-2/Abi-2/Nap1-regulated actin polymerization were impaired in the Rac1 deficient mice. Additionally, the Rac1 cKO lenses were characterized by a shortened epithelial sheet, reduced levels of extracellular matrix (ECM) proteins and increased apoptosis. Taken together, these data uncover the essential role of Rac1 GTPase activity in establishment and maintenance of lens shape, suture formation and capsule integrity, and in fiber cell migration, adhesion and survival, via regulation of actin cytoskeletal dynamics, cell adhesive interactions and ECM turnover. PMID:21945075

Arabidopsis TCH4, regulated by hormones and the environment, encodes a xyloglucan endotransglycosylase

NASA Technical Reports Server (NTRS)

Xu, W.; Purugganan, M. M.; Polisensky, D. H.; Antosiewicz, D. M.; Fry, S. C.; Braam, J.

1995-01-01

Adaptation of plants to environmental conditions requires that sensing of external stimuli be linked to mechanisms of morphogenesis. The Arabidopsis TCH (for touch) genes are rapidly upregulated in expression in response to environmental stimuli, but a connection between this molecular response and developmental alterations has not been established. We identified TCH4 as a xyloglucan endotransglycosylase by sequence similarity and enzyme activity. Xyloglucan endotransglycosylases most likely modify cell walls, a fundamental determinant of plant form. We determined that TCH4 expression is regulated by auxin and brassinosteroids, by environmental stimuli, and during development, by a 1-kb region. Expression was restricted to expanding tissues and organs that undergo cell wall modification. Regulation of genes encoding cell wall-modifying enzymes, such as TCH4, may underlie plant morphogenetic responses to the environment.

FGF8 coordinates tissue elongation and cell epithelialization during early kidney tubulogenesis

PubMed Central

Atsuta, Yuji; Takahashi, Yoshiko

2015-01-01

When a tubular structure forms during early embryogenesis, tubular elongation and lumen formation (epithelialization) proceed simultaneously in a spatiotemporally coordinated manner. We here demonstrate, using the Wolffian duct (WD) of early chicken embryos, that this coordination is regulated by the expression of FGF8, which shifts posteriorly during body axis elongation. FGF8 acts as a chemoattractant on the leader cells of the elongating WD and prevents them from epithelialization, whereas static (‘rear’) cells that receive progressively less FGF8 undergo epithelialization to form a lumen. Thus, FGF8 acts as a binary switch that distinguishes tubular elongation from lumen formation. The posteriorly shifting FGF8 is also known to regulate somite segmentation, suggesting that multiple types of tissue morphogenesis are coordinately regulated by macroscopic changes in body growth. PMID:26130757

Root gravitropism and root hair development constitute coupled developmental responses regulated by auxin homeostasis in the Arabidopsis root apex.

PubMed

Rigas, Stamatis; Ditengou, Franck Anicet; Ljung, Karin; Daras, Gerasimos; Tietz, Olaf; Palme, Klaus; Hatzopoulos, Polydefkis

2013-03-01

Active polar transport establishes directional auxin flow and the generation of local auxin gradients implicated in plant responses and development. Auxin modulates gravitropism at the root tip and root hair morphogenesis at the differentiation zone. Genetic and biochemical analyses provide evidence for defective basipetal auxin transport in trh1 roots. The trh1, pin2, axr2 and aux1 mutants, and transgenic plants overexpressing PIN1, all showing impaired gravity response and root hair development, revealed ectopic PIN1 localization. The auxin antagonist hypaphorine blocked root hair elongation and caused moderate agravitropic root growth, also leading to PIN1 mislocalization. These results suggest that auxin imbalance leads to proximal and distal developmental defects in Arabidopsis root apex, associated with agravitropic root growth and root hair phenotype, respectively, providing evidence that these two auxin-regulated processes are coupled. Cell-specific subcellular localization of TRH1-YFP in stele and epidermis supports TRH1 engagement in auxin transport, and hence impaired function in trh1 causes dual defects of auxin imbalance. The interplay between intrinsic cues determining root epidermal cell fate through the TTG/GL2 pathway and environmental cues including abiotic stresses modulates root hair morphogenesis. As a consequence of auxin imbalance in Arabidopsis root apex, ectopic PIN1 mislocalization could be a risk aversion mechanism to trigger root developmental responses ensuring root growth plasticity. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Kruppel-like factor 5 is Required for Formation and Differentiation of the Bladder Urothelium

PubMed Central

Bell, Sheila. M.; Zhang, Liqian; Mendell, Angela; Xu, Yan; Haitchi, Hans Michael; Lessard, James L.; Whitsett, Jeffrey A.

2011-01-01

SUMMARY Kruppel-like transcription factor 5 (Klf5) was detected in the developing and mature murine bladder urothelium. Herein we report a critical role of KLF5 in the formation and terminal differentiation of the urothelium. The ShhGfpCre transgene was used to delete the Klf5floxed alleles from bladder epithelial cells causing prenatal hydronephrosis, hydroureter, and vesicoureteric reflux. The bladder urothelium failed to stratify and did not express terminal differentiation markers characteristic of basal, intermediate, and umbrella cells including keratins 20, 14, and 5, and the uroplakins. The effects of Klf5 deletion were unique to the developing bladder epithelium since maturation of the epithelium comprising the bladder neck and urethra were unaffected by the lack of KLF5. mRNA analysis identified reductions in Pparγ, Grhl3, Elf3, and Ovol1expression in Klf5 deficient fetal bladders supporting their participation in a transcriptional network regulating bladder urothelial differentiation. KLF5 regulated expression of the mGrhl3 promoter in transient transfection assays. The absence of urothelial Klf5 altered epithelial-mesenchymal signaling leading to the formation of an ectopic alpha smooth muscle actin positive layer of cells subjacent to the epithelium and a thinner detrusor muscle that was not attributable to disruption of SHH signaling, a known mediator of detrusor morphogenesis. Deletion of Klf5 from the developing bladder urothelium blocked epithelial cell differentiation, impaired bladder morphogenesis and function causing hydroureter and hydronephrosis at birth. PMID:21803035

β-Catenin signaling regulates temporally discrete phases of anterior taste bud development

PubMed Central

Thirumangalathu, Shoba; Barlow, Linda A.

2015-01-01

The sense of taste is mediated by multicellular taste buds located within taste papillae on the tongue. In mice, individual taste buds reside in fungiform papillae, which develop at mid-gestation as epithelial placodes in the anterior tongue. Taste placodes comprise taste bud precursor cells, which express the secreted factor sonic hedgehog (Shh) and give rise to taste bud cells that differentiate around birth. We showed previously that epithelial activation of β-catenin is the primary inductive signal for taste placode formation, followed by taste papilla morphogenesis and taste bud differentiation, but the degree to which these later elements were direct or indirect consequences of β-catenin signaling was not explored. Here, we define discrete spatiotemporal functions of β-catenin in fungiform taste bud development. Specifically, we show that early epithelial activation of β-catenin, before taste placodes form, diverts lingual epithelial cells from a taste bud fate. By contrast, β-catenin activation a day later within Shh+ placodes, expands taste bud precursors directly, but enlarges papillae indirectly. Further, placodal activation of β-catenin drives precocious differentiation of Type I glial-like taste cells, but not other taste cell types. Later activation of β-catenin within Shh+ precursors during papilla morphogenesis also expands taste bud precursors and accelerates Type I cell differentiation, but papilla size is no longer enhanced. Finally, although Shh regulates taste placode patterning, we find that it is dispensable for the accelerated Type I cell differentiation induced by β-catenin. PMID:26525674

NF-kappaB signaling blockade by Bay 11-7085 during early cardiac morphogenesis induces alterations of the outflow tract in chicken heart.

PubMed

Hernández-Gutierrez, S; García-Peláez, I; Zentella-Dehesa, A; Ramos-Kuri, M; Hernández-Franco, P; Hernández-Sánchez, F; Rojas, E

2006-07-01

Nuclear factor kappaB (NF-kappaB) is a pleiotropic transcription factor implicated in the regulation of diverse morphologic cardiac alterations, for which the p50 and p65 subunits form the most prevalent dimeric form in the heart. NF-kappaB is inactivated by proteins of the IkappaB family, which trap it in the cytoplasm. It is not known whether NF-kappaB influences cardiac development. Here we investigated the role of NF-kappaB in regulating transcription in chicken heart morphogenesis. Specifically, we tested whether NF-kappaB activation is required for normal formation of the outflow tract (OFT) during a critical stage of heart development. We designed a reporter vector with kappaB binding sites for Rel family members in the promoter, upstream from the cDNA of Green Fluorescent Protein (GFP). This construct was injected directly into the developing heart of chicken embryos. NF-kappaB activation was subsequently inhibited by administration of the specific pharmacological agent Bay 11-7085. We found that forced NF-kappaB expression was associated with multiple congenital cardiac alterations of the OFT (mainly IVC, DORV and great arteries stenosis). These findings indicate that blockade of NF-kappaB induces apoptosis and is an important factor in the development of OFT during cardiogenesis. However, it remains unknown which members of the Rel family are relevant in this process.

Synthetic Morphogenesis.

PubMed

Teague, Brian P; Guye, Patrick; Weiss, Ron

2016-09-01

Throughout biology, function is intimately linked with form. Across scales ranging from subcellular to multiorganismal, the identity and organization of a biological structure's subunits dictate its properties. The field of molecular morphogenesis has traditionally been concerned with describing these links, decoding the molecular mechanisms that give rise to the shape and structure of cells, tissues, organs, and organisms. Recent advances in synthetic biology promise unprecedented control over these molecular mechanisms; this opens the path to not just probing morphogenesis but directing it. This review explores several frontiers in the nascent field of synthetic morphogenesis, including programmable tissues and organs, synthetic biomaterials and programmable matter, and engineering complex morphogenic systems de novo. We will discuss each frontier's objectives, current approaches, constraints and challenges, and future potential. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

Dmrt1 is necessary for male sexual development in zebrafish

PubMed Central

Webster, Kaitlyn A.; Schach, Ursula; Ordaz, Angel; Steinfeld, Jocelyn S.; Draper, Bruce W.; Siegfried, Kellee R.

2018-01-01

The dmrt1 (doublesex and mab-3 related transcription factor 1) gene is a key regulator of sex determination and/or gonadal sex differentiation across metazoan animals. This is unusual given that sex determination genes are typically not well conserved. The mechanisms by which zebrafish sex is determined have remained elusive due to the lack of sex chromosomes and the complex polygenic nature of sex determination in domesticated strains. To investigate the role of dmrt1 in zebrafish sex determination and gonad development, we isolated mutations disrupting this gene. We found that the majority of dmrt1 mutant fish develop as fertile females suggesting a complete male-to-female sex reversal in mutant animals that would have otherwise developed as males. A small percentage of mutant animals became males, but were sterile and displayed testicular dysgenesis. Therefore zebrafish dmrt1 functions in male sex determination and testis development. Mutant males had aberrant gonadal development at the onset of gonadal sex-differentiation, displaying reduced oocyte apoptosis followed by development of intersex gonads and failed testis morphogenesis and spermatogenesis. By contrast, female ovaries developed normally. We found that Dmrt1 is necessary for normal transcriptional regulation of the amh (anti-Müllerian hormone) and foxl2 (forkhead box L2) genes, which are thought to be important for male or female sexual development respectively. Interestingly, we identified one dmrt1 mutant allele that cooperates with a linked segregation distorter locus to generate an apparent XY sex determination mechanism. We conclude that dmrt1 is dispensable for ovary development but necessary for testis development in zebrafish, and that dmrt1 promotes male development by transcriptionally regulating male and female genes as has been described in other animals. Furthermore, the strong sex-ratio bias caused by dmrt1 reduction-of-function points to potential mechanisms through which sex chromosomes may evolve. PMID:27940159

Palate morphogenesis in mouse embryos after x-irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Callas, Gerald; Walker, Bruce E.

1963-01-01

The development of cleft palate was investigated by irradiating pregnant female C57BL and A/Jax mice on the 11 1/3 day of gestation with 300-r, whole-body doses and examining the fetuses at subsequent intervals. When palate stage was compared with chronological age, morphological rating, or embryonic weight, it was obvious that intermediate stages of palate closure persisted in x-irradiated embryos long after such stages had been passed in normal embryos. Thus, movement of the palatine shelves from the sagittal to the horizontal plane was retarded by x irradiation. Measurements of head and palate did not show any consistent disproportionality of palatemore » growth in the xirradiated embryos except that which resulted from retardation of shelf movement. X irradiation affected A/Jax strain litters more severely than C57BL strain litters according to cleft palate frequency and average palate stage at 18 1/3 days postconception. Cleft palate was seen in 73.1% of strain C57BL fetuses and in 99.5% of A/Jax fetuses. A variety of malformations other than cleft palate were also observed in the offspring of treated mice. Morphologic analysis of cleft palate development after xray treatment gave essentially the same results as comparable analyses of cleft palates produced by cortisone, hypervitaminosis A, and riboflavin deficiency. (TCO)« less

Kidney and bladder calculi in spontaneously hypertensive rats.

PubMed Central

Wexler, B. C.; McMurtry, J. P.

1981-01-01

Naturally occurring kidney stones are rare in animals. The Japanese strains of spontaneously hypertensive rats (SHR) are normotensive at birth but develop high blood pressure, hyperglycaemia and hyperlipidaemia as they mature. The SHR strain is prone to develop kidney stones. A unique sub-strain of SHR has been developed in which some animals develop hypothalamic obesity concomitantly with their rising blood pressure, i.e. Obese/SHR. The Obese/SHR characteristically develop microscopic kidney stones which become detached at an early stage of formation, migrate to the bladder, and grow by concretion into huge, rounded calculi. The stone nidus starts as a subepithelial cyst-like focus containing oedema, colloidal acidic mucoprotein, and red and white blood cells suspended on a delicate network of fibrils. THe nidi grow by concretion of an admixture of calcium and acidic protein in a lamellar arrangement. The disparate morphogenesis and anatomic location of kidney stones in Obese is opposed to non-obese/SHR suggest that calculus formation may be governed by specific differences in genetic programming. The incidence of kidney stones parallels the severity and chronicity of the hypertension in SHR, non-obese and Obese/SHR, and the Cushingoid habitus in the Obese/SHR. Images Fig. 1 Fig. 3 Fig. 2 Fig. 4 Fig. 5 Fig. 6 PMID:7295530

A low-density culture method of cerebellar granule neurons with paracrine support applicable for the study of neuronal morphogenesis.

PubMed

Kubota, Kenta; Seno, Takeshi; Konishi, Yoshiyuki

2013-11-20

Cerebellar granule neuronal cultures have been used to study the molecular mechanisms underlying neuronal functions, including neuronal morphogenesis. However, a limitation of this system is the difficulty to analyze isolated neurons because these are required to be maintained at a high density. Therefore, in the present study, we aimed to develop a simple and cost-effective method for culturing low-density cerebellar granule neurons. Cerebellar granule cells at two different densities (low- and high-density) were co-cultivated in order for the low-density culture to be supported by the paracrine signals from the high-density culture. This method enabled morphology analysis of isolated cerebellar granule neurons without astrocytic feeder cultures or supplements such as B27. Using this method, we investigated the function of a polarity factor. Studies using hippocampal neurons suggested that glycogen synthase kinase-3 (GSK-3) is an essential regulator of neuronal polarity, and inhibition of GSK-3 results in the formation of multiple axons. Pharmacological inhibitors for GSK-3 (6-bromoindirubin-3'-oxime and lithium chloride) did not cause the formation of multiple axons of cerebellar granule neurons but significantly reduced their length. Consistent results were obtained by introducing kinase-dead form of GSK-3 beta (K85A). These results indicated that GSK-3 is not directly involved in the control of neuronal polarity in cerebellar granule neurons. Overall, this study provides a simple method for culturing low-density cerebellar granule neurons and insights in to the neuronal-type dependent function of GSK-3 in neuronal morphogenesis. © 2013 Elsevier B.V. All rights reserved.

PTEN induces apoptosis and cavitation via HIF-2-dependent Bnip3 upregulation during epithelial lumen formation.

PubMed

Qi, Y; Liu, J; Saadat, S; Tian, X; Han, Y; Fong, G-H; Pandolfi, P P; Lee, L Y; Li, S

2015-05-01

The tumor suppressor phosphatase and tensin homolog (PTEN) dephosphorylates PIP3 and antagonizes the prosurvival PI3K-Akt pathway. Targeted deletion of PTEN in mice led to early embryonic lethality. To elucidate its role in embryonic epithelial morphogenesis and the underlying mechanisms, we used embryonic stem cell-derived embryoid body (EB), an epithelial cyst structurally similar to the periimplantation embryo. PTEN is upregulated during EB morphogenesis in parallel with apoptosis of core cells, which mediates EB cavitation. Genetic ablation of PTEN causes Akt overactivation, apoptosis resistance and cavitation blockade. However, rescue experiments using mutant PTEN and pharmacological inhibition of Akt suggest that the phosphatase activity of PTEN and Akt are not involved in apoptosis-mediated cavitation. Instead, hypoxia-induced upregulation of Bnip3, a proapoptotic BH3-only protein, mediates PTEN-dependent apoptosis and cavitation. PTEN inactivation inhibits hypoxia- and reactive oxygen species-induced Bnip3 elevation. Overexpression of Bnip3 in PTEN-null EBs rescues apoptosis of the core cells. Mechanistically, suppression of Bnip3 following PTEN loss is likely due to reduction of hypoxia-inducible factor-2α (HIF-2α) because forced expression of an oxygen-stable HIF-2α mutant rescues Bnip3 expression and apoptosis. Lastly, we show that HIF-2α is upregulated by PTEN at both transcriptional and posttranscriptional levels. Ablation of prolyl hydroxylase domain-containing protein 2 (PHD2) in normal EBs or inhibition of PHD activities in PTEN-null EBs stabilizes HIF-2α and induces Bnip3 and caspase-3 activation. Altogether, these results suggest that PTEN is required for apoptosis-mediated cavitation during epithelial morphogenesis by regulating the expression of HIF-2α and Bnip3.

Rooster feathering, androgenic alopecia, and hormone dependent tumor growth: What is in common?

PubMed Central

Mayer, Julie Ann; Chuong, Cheng-Ming; Widelitz, Randall

2015-01-01

Different epithelial organs form as a result of epithelial - mesenchymal interactions and share a common theme modulated by variations (Chuong edit. In Molecular Basis of Epithelial Appendage Morphogenesis, 1998). One of the major modulators is the sex hormone pathway that acts on the prototype signaling pathway to alter organ phenotypes. Here we focus on how the sex hormone pathway interfaces with epithelia morphogenesis related signaling pathways. We first survey these sex hormone regulated morphogenetic processes in various epithelial organs. Sexual dimorphism of hairs and feathers has implications in sexual selection. Diseases of these pathways result in androgenic alopecia, hirsutism, henny feathering, etc. The growth and development of mammary glands, prostate glands and external genitalia essential for reproductive function are also dependent on sex hormones. Diseases affecting these organs include congenital anomalies and hormone dependent type of breast and prostate cancers. To study the role of sex hormones in new growth in the context of system biology / pathology, an in vivo model in which organ formation starts from stem cells is essential. With recent developments (Yu et al., The morphogenesis of feathers. Nature 420:308–312, 2002), the growth of tail feathers in roosters and hens has become a testable model in which experimental manipulations are possible. We show exemplary data of differences in their growth rate, proliferative cell population and signaling molecule expression. Working hypotheses are proposed on how the sex hormone pathways may interact with growth pathways. It is now possible to test these hypotheses using the chicken model to learn fundamental mechanisms on how sex hormones affect organogenesis, epithelial organ cycling, and growth related tumorigenesis. PMID:15617560

MiR-181a-5p is downregulated in hepatocellular carcinoma and suppresses motility, invasion and branching-morphogenesis by directly targeting c-Met.

PubMed

Korhan, Peyda; Erdal, Esra; Atabey, Neşe

2014-08-08

c-Met receptor tyrosine kinase has been regarded as a promising therapeutic target for hepatocellular carcinoma (HCC). Recently, microRNAs (miRNAs) have been shown as a novel mechanism to control c-Met expression in cancer. In this study, we investigate the potential contribution of miR-181a-5p dysregulation to the biology of c-Met overexpression in HCC. Herein, we found an inverse expression pattern between miR-181a-5p and c-Met expression in normal, cirrhotic and HCC liver tissues. Luciferase assay confirmed that miR-181a-5p binding to the 3'-UTR of c-Met downregulated the expression of c-Met in HCC cells. Overexpression of miR-181a-5p suppressed both HGF-independent and -dependent activation of c-Met and consequently diminished branching-morphogenesis and invasion. Combined treatment with miR-181a-5p and c-Met inhibitor led to a further inhibition of c-Met-driven cellular activities. Knockdown of miR-181a-5p promoted HGF-independent/-dependent signaling of c-Met and accelerated migration, invasion and branching-morphogenesis. In conclusion, our results demonstrated for the first time that c-Met is a functional target gene of miR-181a-5p and the loss of miR-181a-5p expression led to the activation of c-Met-mediated oncogenic signaling in hepatocarcinogenesis. These findings display a novel molecular mechanism of c-Met regulation in HCC and strategies to increase miR-181a5p level might be an alternative approach for the enhancement of the inhibitory effects of c-Met inhibitors. Copyright © 2014 Elsevier Inc. All rights reserved.

Unique patterns of organization and migration of FGF-expressing cells during Drosophila morphogenesis.

PubMed

Du, Lijuan; Zhou, Amy; Patel, Akshay; Rao, Mishal; Anderson, Kelsey; Roy, Sougata

2017-07-01

Fibroblast growth factors (FGF) are essential signaling proteins that regulate diverse cellular functions in developmental and metabolic processes. In Drosophila, the FGF homolog, branchless (bnl) is expressed in a dynamic and spatiotemporally restricted pattern to induce branching morphogenesis of the trachea, which expresses the Bnl-receptor, breathless (btl). Here we have developed a new strategy to determine bnl- expressing cells and study their interactions with the btl-expressing cells in the range of tissue patterning during Drosophila development. To enable targeted gene expression specifically in the bnl expressing cells, a new LexA based bnl enhancer trap line was generated using CRISPR/Cas9 based genome editing. Analyses of the spatiotemporal expression of the reporter in various embryonic stages, larval or adult tissues and in metabolic hypoxia, confirmed its target specificity and versatility. With this tool, new bnl expressing cells, their unique organization and functional interactions with the btl-expressing cells were uncovered in a larval tracheoblast niche in the leg imaginal discs, in larval photoreceptors of the developing retina, and in the embryonic central nervous system. The targeted expression system also facilitated live imaging of simultaneously labeled Bnl sources and tracheal cells, which revealed a unique morphogenetic movement of the embryonic bnl- source. Migration of bnl- expressing cells may create a dynamic spatiotemporal pattern of the signal source necessary for the directional growth of the tracheal branch. The genetic tool and the comprehensive profile of expression, organization, and activity of various types of bnl-expressing cells described in this study provided us with an important foundation for future research investigating the mechanisms underlying Bnl signaling in tissue morphogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

8-Oxoguanine DNA glycosylase 1 (ogg1) maintains the function of cardiac progenitor cells during heart formation in zebrafish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Lifeng; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 210029; Zhou, Yong

Genomic damage may devastate the potential of progenitor cells and consequently impair early organogenesis. We found that ogg1, a key enzyme initiating the base-excision repair, was enriched in the embryonic heart in zebrafish. So far, little is known about DNA repair in cardiogenesis. Here, we addressed the critical role of ogg1 in cardiogenesis for the first time. ogg1 mainly expressed in the anterior lateral plate mesoderm (ALPM), the primary heart tube, and subsequently the embryonic myocardium by in situ hybridisation. Loss of ogg1 resulted in severe cardiac morphogenesis and functional abnormalities, including the short heart length, arrhythmia, decreased cardiomyocytes andmore » nkx2.5{sup +} cardiac progenitor cells. Moreover, the increased apoptosis and repressed proliferation of progenitor cells caused by ogg1 deficiency might contribute to the heart phenotype. The microarray analysis showed that the expression of genes involved in embryonic heart tube morphogenesis and heart structure were significantly changed due to the lack of ogg1. Among those, foxh1 is an important partner of ogg1 in the cardiac development in response to DNA damage. Our work demonstrates the requirement of ogg1 in cardiac progenitors and heart development in zebrafish. These findings may be helpful for understanding the aetiology of congenital cardiac deficits. - Highlights: • A key DNA repair enzyme ogg1 is expressed in the embryonic heart in zebrafish. • We found that ogg1 is essential for normal cardiac morphogenesis in zebrafish. • The production of embryonic cardiomyocytes requires appropriate ogg1 expression. • Ogg1 critically regulated proliferation of cardiac progenitor cells in zebrafish. • foxh1 is a partner of ogg1 in the cardiac development in response to DNA damage.« less

Analysis of the role of the Spitzenkörper in fungal morphogenesis by computer simulation of apical branching in Aspergillus niger

PubMed Central

Reynaga-Peña, Cristina G.; Gierz, Gerhard; Bartnicki-Garcia, Salomon

1997-01-01

High-resolution video microscopy, image analysis, and computer simulation were used to study the role of the Spitzenkörper (Spk) in apical branching of ramosa-1, a temperature-sensitive mutant of Aspergillus niger. A shift to the restrictive temperature led to a cytoplasmic contraction that destabilized the Spk, causing its disappearance. After a short transition period, new Spk appeared where the two incipient apical branches emerged. Changes in cell shape, growth rate, and Spk position were recorded and transferred to the fungus simulator program to test the hypothesis that the Spk functions as a vesicle supply center (VSC). The simulation faithfully duplicated the elongation of the main hypha and the two apical branches. Elongating hyphae exhibited the growth pattern described by the hyphoid equation. During the transition phase, when no Spk was visible, the growth pattern was nonhyphoid, with consecutive periods of isometric and asymmetric expansion; the apex became enlarged and blunt before the apical branches emerged. Video microscopy images suggested that the branch Spk were formed anew by gradual condensation of vesicle clouds. Simulation exercises where the VSC was split into two new VSCs failed to produce realistic shapes, thus supporting the notion that the branch Spk did not originate by division of the original Spk. The best computer simulation of apical branching morphogenesis included simulations of the ontogeny of branch Spk via condensation of vesicle clouds. This study supports the hypothesis that the Spk plays a major role in hyphal morphogenesis by operating as a VSC—i.e., by regulating the traffic of wall-building vesicles in the manner predicted by the hyphoid model. PMID:9256441

Frazzled/DCC facilitates cardiac cell outgrowth and attachment during Drosophila dorsal vessel formation.

PubMed

Macabenta, Frank D; Jensen, Amber G; Cheng, Yi-Shan; Kramer, Joseph J; Kramer, Sunita G

2013-08-15

Drosophila embryonic dorsal vessel (DV) morphogenesis is a highly stereotyped process that involves the migration and morphogenesis of 52 pairs of cardioblasts (CBs) in order to form a linear tube. This process requires spatiotemporally-regulated localization of signaling and adhesive proteins in order to coordinate the formation of a central lumen while maintaining simultaneous adhesion between CBs. Previous studies have shown that the Slit/Roundabout and Netrin/Unc5 repulsive signaling pathways facilitate site-specific loss of adhesion between contralateral CBs in order to form a luminal space. However, the concomitant mechanism by which attraction initiates CB outgrowth and discrete localization of adhesive proteins remains poorly understood. Here we provide genetic evidence that Netrin signals through DCC (Deleted in Colorectal Carcinoma)/UNC-40/Frazzled (Fra) to mediate CB outgrowth and attachment and that this function occurs prior to and independently of Netrin/UNC-5 signaling. fra mRNA is expressed in the CBs prior to and during DV morphogenesis. Loss-of-fra-function results in significant defects in cell shape and alignment between contralateral CB rows. In addition, CB outgrowth and attachment is impaired in both fra loss- and gain-of-function mutants. Deletion of both Netrin genes (NetA and NetB) results in CB attachment phenotypes similar to fra mutants. Similar defects are also seen when both fra and unc5 are deleted. Finally we show that Fra accumulates at dorsal and ventral leading edges of paired CBs, and this localization is dependent upon Netrin. We propose that while repulsive guidance mechanisms contribute to lumen formation by preventing luminal domains from coming together, site-specific Netrin/Frazzled signaling mediates CB attachment. Copyright © 2013 Elsevier Inc. All rights reserved.

Ras1 interacts with multiple new signaling and cytoskeletal loci in Drosophila eggshell patterning and morphogenesis.

PubMed Central

Schnorr, J D; Holdcraft, R; Chevalier, B; Berg, C A

2001-01-01

Little is known about the genes that interact with Ras signaling pathways to regulate morphogenesis. The synthesis of dorsal eggshell structures in Drosophila melanogaster requires multiple rounds of Ras signaling followed by dramatic epithelial sheet movements. We took advantage of this process to identify genes that link patterning and morphogenesis; we screened lethal mutations on the second chromosome for those that could enhance a weak Ras1 eggshell phenotype. Of 1618 lethal P-element mutations tested, 13 showed significant enhancement, resulting in forked and fused dorsal appendages. Our genetic and molecular analyses together with information from the Berkeley Drosophila Genome Project reveal that 11 of these lines carry mutations in previously characterized genes. Three mutations disrupt the known Ras1 cell signaling components Star, Egfr, and Blistered, while one mutation disrupts Sec61beta, implicated in ligand secretion. Seven lines represent cell signaling and cytoskeletal components that are new to the Ras1 pathway; these are Chickadee (Profilin), Tec29, Dreadlocks, POSH, Peanut, Smt3, and MESK2, a suppressor of dominant-negative Ksr. A twelfth insertion disrupts two genes, Nrk, a "neurospecific" receptor tyrosine kinase, and Tpp, which encodes a neuropeptidase. These results suggest that Ras1 signaling during oogenesis involves novel components that may be intimately associated with additional signaling processes and with the reorganization of the cytoskeleton. To determine whether these Ras1 Enhancers function upstream or downstream of the Egf receptor, four mutations were tested for their ability to suppress an activated Egfr construct (lambdatop) expressed in oogenesis exclusively in the follicle cells. Mutations in Star and l(2)43Bb had no significant effect upon the lambdatop eggshell defect whereas smt3 and dock alleles significantly suppressed the lambdatop phenotype. PMID:11606538

Ras1 interacts with multiple new signaling and cytoskeletal loci in Drosophila eggshell patterning and morphogenesis.

PubMed

Schnorr, J D; Holdcraft, R; Chevalier, B; Berg, C A

2001-10-01

Little is known about the genes that interact with Ras signaling pathways to regulate morphogenesis. The synthesis of dorsal eggshell structures in Drosophila melanogaster requires multiple rounds of Ras signaling followed by dramatic epithelial sheet movements. We took advantage of this process to identify genes that link patterning and morphogenesis; we screened lethal mutations on the second chromosome for those that could enhance a weak Ras1 eggshell phenotype. Of 1618 lethal P-element mutations tested, 13 showed significant enhancement, resulting in forked and fused dorsal appendages. Our genetic and molecular analyses together with information from the Berkeley Drosophila Genome Project reveal that 11 of these lines carry mutations in previously characterized genes. Three mutations disrupt the known Ras1 cell signaling components Star, Egfr, and Blistered, while one mutation disrupts Sec61beta, implicated in ligand secretion. Seven lines represent cell signaling and cytoskeletal components that are new to the Ras1 pathway; these are Chickadee (Profilin), Tec29, Dreadlocks, POSH, Peanut, Smt3, and MESK2, a suppressor of dominant-negative Ksr. A twelfth insertion disrupts two genes, Nrk, a "neurospecific" receptor tyrosine kinase, and Tpp, which encodes a neuropeptidase. These results suggest that Ras1 signaling during oogenesis involves novel components that may be intimately associated with additional signaling processes and with the reorganization of the cytoskeleton. To determine whether these Ras1 Enhancers function upstream or downstream of the Egf receptor, four mutations were tested for their ability to suppress an activated Egfr construct (lambdatop) expressed in oogenesis exclusively in the follicle cells. Mutations in Star and l(2)43Bb had no significant effect upon the lambdatop eggshell defect whereas smt3 and dock alleles significantly suppressed the lambdatop phenotype.

Oriented cell division: new roles in guiding skin wound repair and regeneration

PubMed Central

Yang, Shaowei; Ma, Kui; Geng, Zhijun; Sun, Xiaoyan; Fu, Xiaobing

2015-01-01

Tissue morphogenesis depends on precise regulation and timely co-ordination of cell division and also on the control of the direction of cell division. Establishment of polarity division axis, correct alignment of the mitotic spindle, segregation of fate determinants equally or unequally between daughter cells, are essential for the realization of oriented cell division. Furthermore, oriented cell division is regulated by intrinsic cues, extrinsic cues and other cues, such as cell geometry and polarity. However, dysregulation of cell division orientation could lead to abnormal tissue development and function. In the present study, we review recent studies on the molecular mechanism of cell division orientation and explain their new roles in skin repair and regeneration. PMID:26582817

Oligosaccharins, brassinolides, and jasmonates: nontraditional regulators of plant growth, development, and gene expression.

PubMed

Creelman, R A; Mullet, J E

1997-07-01

Each of the nontraditional plant hormones reviewed in this article, oligosaccharins, brassinolides, and JA, can exert major effects on plant growth and development. However, in many cases, the mechanisms by which these compounds are involved in the endogenous regulation of morphogenesis remain to be established. Nevertheless, the use of mutant or transgenic plants with altered levels or perception of these hormones is leading to phenomenal increases in our understanding of the roles they play in the life cycle of plants. It is likely that in the future, novel modulators of plant growth and development will be identified; some will perhaps be related to the peptide encoded by ENOD40 (Van de Sande et al., 1996), which modifies the action of auxin.

Reactive oxygen species in the presence of high glucose alter ureteric bud morphogenesis.

PubMed

Zhang, Shao-Ling; Chen, Yun-Wen; Tran, Stella; Chenier, Isabelle; Hébert, Marie-Josée; Ingelfinger, Julie R

2007-07-01

Renal malformations are a major cause of childhood renal failure. During the development of the kidney, ureteric bud (UB) branching morphogenesis is critical for normal nephrogenesis. These studies investigated whether renal UB branching morphogenesis is altered by a high ambient glucose environment and studied underlying mechanism(s). Kidney explants that were isolated from different periods of gestation (embryonic days 12 to 18) from Hoxb7-green fluorescence protein mice were cultured for 24 h in either normal d-glucose (5 mM) or high d-glucose (25 mM) medium with or without various inhibitors. Alterations in renal morphogenesis were assessed by fluorescence microscopy. Paired-homeobox 2 (Pax-2) gene expression was determined by real-time quantitative PCR, Western blotting, and immunohistology. The results revealed that high d-glucose (25 mM) specifically stimulates UB branching morphogenesis via Pax-2 gene expression, whereas other glucose analogs, such as d-mannitol, l-glucose, and 2-deoxy-d-glucose, had no effect. The stimulatory effect of high glucose on UB branching was blocked in the presence of catalase and inhibitors of NADPH oxidase, mitochondrial electron transport chain complex I, and Akt signaling. Moreover, in in vivo studies, it seems that high glucose induces, via Pax-2 (mainly localized in UB), acceleration of UB branching but not nephron formation. Taken together, these data demonstrate that high glucose alters UB branching morphogenesis. This occurs, at least in part, via reactive oxygen species generation, activation of Akt signaling, and upregulation of Pax-2 gene expression.

A System for Modelling Cell–Cell Interactions during Plant Morphogenesis

PubMed Central

Dupuy, Lionel; Mackenzie, Jonathan; Rudge, Tim; Haseloff, Jim

2008-01-01

Background and aims During the development of multicellular organisms, cells are capable of interacting with each other through a range of biological and physical mechanisms. A description of these networks of cell–cell interactions is essential for an understanding of how cellular activity is co-ordinated in regionalized functional entities such as tissues or organs. The difficulty of experimenting on living tissues has been a major limitation to describing such systems, and computer modelling appears particularly helpful to characterize the behaviour of multicellular systems. The experimental difficulties inherent to the multitude of parallel interactions that underlie cellular morphogenesis have led to the need for computer models. Methods A new generic model of plant cellular morphogenesis is described that expresses interactions amongst cellular entities explicitly: the plant is described as a multi-scale structure, and interactions between distinct entities is established through a topological neighbourhood. Tissues are represented as 2D biphasic systems where the cell wall responds to turgor pressure through a viscous yielding of the cell wall. Key Results This principle was used in the development of the CellModeller software, a generic tool dedicated to the analysis and modelling of plant morphogenesis. The system was applied to three contrasting study cases illustrating genetic, hormonal and mechanical factors involved in plant morphogenesis. Conclusions Plant morphogenesis is fundamentally a cellular process and the CellModeller software, through its underlying generic model, provides an advanced research tool to analyse coupled physical and biological morphogenetic mechanisms. PMID:17921524

Synthesis and morphogenesis of organic and inorganic polymers by means of biominerals and biomimetic materials.

PubMed

Kijima, Misako; Oaki, Yuya; Munekawa, Yurika; Imai, Hiroaki

2013-02-11

We have studied the simultaneous synthesis and morphogenesis of polymer materials with hierarchical structures from nanoscopic to macroscopic scales. The morphologies of the original materials can be replicated to the polymer materials. In general, it is not easy to achieve the simultaneous synthesis and morphogenesis of polymer material even using host materials. In the present work, four biominerals and three biomimetic mesocrystal structures are used as the host materials or templates and polypyrrole, poly(3-hexylthiopehene), and silica were used as the precursors for the simultaneous syntheses and morphogenesis of polymer materials. The host materials with the hierarchical structure possess the nanospace for the incorporation of the monomers. After the incorporation of the monomers, the polymerization reaction proceeds in the nanospace with addition of the initiator agents. Then, the dissolution of the host materials leads to the formation and morphogenesis of the polymer materials. The scheme of the replication can be classified into the three types based on the structures of the host materials (types I-III). The type I template facilitates the hierarchical replication of the whole host material, type II mediates the hierarchical surface replication, and type III induces the formation of the two-dimensional nanosheets. Based on these results, the approach for the coupled synthesis and morphogenesis can be applied to a variety of combinations of the templates and polymer materials. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Genomic Diversity of Phages Infecting Probiotic Strains of Lactobacillus paracasei

PubMed Central

Rousseau, Geneviève M.; Capra, María L.; Quiberoni, Andrea; Tremblay, Denise M.; Labrie, Simon J.

2015-01-01

Strains of the Lactobacillus casei group have been extensively studied because some are used as probiotics in foods. Conversely, their phages have received much less attention. We analyzed the complete genome sequences of five L. paracasei temperate phages: CL1, CL2, iLp84, iLp1308, and iA2. Only phage iA2 could not replicate in an indicator strain. The genome lengths ranged from 34,155 bp (iA2) to 39,474 bp (CL1). Phages iA2 and iLp1308 (34,176 bp) possess the smallest genomes reported, thus far, for phages of the L. casei group. The GC contents of the five phage genomes ranged from 44.8 to 45.6%. As observed with many other phages, their genomes were organized as follows: genes coding for DNA packaging, morphogenesis, lysis, lysogeny, and replication. Phages CL1, CL2, and iLp1308 are highly related to each other. Phage iLp84 was also related to these three phages, but the similarities were limited to gene products involved in DNA packaging and structural proteins. Genomic fragments of phages CL1, CL2, iLp1308, and iLp84 were found in several genomes of L. casei strains. Prophage iA2 is unrelated to these four phages, but almost all of its genome was found in at least four L. casei strains. Overall, these phages are distinct from previously characterized Lactobacillus phages. Our results highlight the diversity of L. casei phages and indicate frequent DNA exchanges between phages and their hosts. PMID:26475105

Auxin-Mediated Transcriptional System with a Minimal Set of Components Is Critical for Morphogenesis through the Life Cycle in Marchantia polymorpha

PubMed Central

Kato, Hirotaka; Ishizaki, Kimitsune; Kouno, Masaru; Shirakawa, Makoto; Bowman, John L.; Nishihama, Ryuichi; Kohchi, Takayuki

2015-01-01

The plant hormone auxin regulates many aspects of plant growth and development. Recent progress in Arabidopsis provided a scheme that auxin receptors, TIR1/AFBs, target transcriptional co-repressors, AUX/IAAs, for degradation, allowing ARFs to regulate transcription of auxin responsive genes. The mechanism of auxin-mediated transcriptional regulation is considered to have evolved around the time plants adapted to land. However, little is known about the role of auxin-mediated transcription in basal land plant lineages. We focused on the liverwort Marchantia polymorpha, which belongs to the earliest diverging lineage of land plants. M. polymorpha has only a single TIR1/AFB (MpTIR1), a single AUX/IAA (MpIAA), and three ARFs (MpARF1, MpARF2, and MpARF3) in the genome. Expression of a dominant allele of MpIAA with mutations in its putative degron sequence conferred an auxin resistant phenotype and repressed auxin-dependent expression of the auxin response reporter proGH3:GUS. We next established a system for DEX-inducible auxin-response repression by expressing the putatively stabilized MpIAA protein fused with the glucocorticoid receptor domain (MpIAAmDII-GR). Repression of auxin responses in proMpIAA:MpIAAmDII-GR plants caused severe defects in various developmental processes, including gemmaling development, dorsiventrality, organogenesis, and tropic responses. Transient transactivation assays showed that the three MpARFs had different transcriptional activities, each corresponding to their phylogenetic classifications. Moreover, MpIAA and MpARF proteins interacted with each other with different affinities. This study provides evidence that pleiotropic auxin responses can be achieved by a minimal set of auxin signaling factors and suggests that the transcriptional regulation mediated by TIR1/AFB, AUX/IAA, and three types of ARFs might have been a key invention to establish body plans of land plants. We propose that M. polymorpha is a good model to investigate the principles and the evolution of auxin-mediated transcriptional regulation and its roles in land plant morphogenesis. PMID:26020919

Auxin-Mediated Transcriptional System with a Minimal Set of Components Is Critical for Morphogenesis through the Life Cycle in Marchantia polymorpha.

PubMed

Kato, Hirotaka; Ishizaki, Kimitsune; Kouno, Masaru; Shirakawa, Makoto; Bowman, John L; Nishihama, Ryuichi; Kohchi, Takayuki

2015-05-01

The plant hormone auxin regulates many aspects of plant growth and development. Recent progress in Arabidopsis provided a scheme that auxin receptors, TIR1/AFBs, target transcriptional co-repressors, AUX/IAAs, for degradation, allowing ARFs to regulate transcription of auxin responsive genes. The mechanism of auxin-mediated transcriptional regulation is considered to have evolved around the time plants adapted to land. However, little is known about the role of auxin-mediated transcription in basal land plant lineages. We focused on the liverwort Marchantia polymorpha, which belongs to the earliest diverging lineage of land plants. M. polymorpha has only a single TIR1/AFB (MpTIR1), a single AUX/IAA (MpIAA), and three ARFs (MpARF1, MpARF2, and MpARF3) in the genome. Expression of a dominant allele of MpIAA with mutations in its putative degron sequence conferred an auxin resistant phenotype and repressed auxin-dependent expression of the auxin response reporter proGH3:GUS. We next established a system for DEX-inducible auxin-response repression by expressing the putatively stabilized MpIAA protein fused with the glucocorticoid receptor domain (MpIAA(mDII)-GR). Repression of auxin responses in (pro)MpIAA:MpIAA(mDII)-GR plants caused severe defects in various developmental processes, including gemmaling development, dorsiventrality, organogenesis, and tropic responses. Transient transactivation assays showed that the three MpARFs had different transcriptional activities, each corresponding to their phylogenetic classifications. Moreover, MpIAA and MpARF proteins interacted with each other with different affinities. This study provides evidence that pleiotropic auxin responses can be achieved by a minimal set of auxin signaling factors and suggests that the transcriptional regulation mediated by TIR1/AFB, AUX/IAA, and three types of ARFs might have been a key invention to establish body plans of land plants. We propose that M. polymorpha is a good model to investigate the principles and the evolution of auxin-mediated transcriptional regulation and its roles in land plant morphogenesis.

Prostate organogenesis: tissue induction, hormonal regulation and cell type specification

PubMed Central

Toivanen, Roxanne

2017-01-01

Prostate organogenesis is a complex process that is primarily mediated by the presence of androgens and subsequent mesenchyme-epithelial interactions. The investigation of prostate development is partly driven by its potential relevance to prostate cancer, in particular the apparent re-awakening of key developmental programs that occur during tumorigenesis. However, our current knowledge of the mechanisms that drive prostate organogenesis is far from complete. Here, we provide a comprehensive overview of prostate development, focusing on recent findings regarding sexual dimorphism, bud induction, branching morphogenesis and cellular differentiation. PMID:28400434

Casein Kinase I Isoform Hrr25 Is a Negative Regulator of Haa1 in the Weak Acid Stress Response Pathway in Saccharomyces cerevisiae.

PubMed

Collins, Morgan E; Black, Joshua J; Liu, Zhengchang

2017-07-01

Haa1 is a transcription factor that adapts Saccharomyces cerevisiae cells to weak organic acid stresses by activating the expression of various genes. Many of these genes encode membrane proteins, such as TPO2 and YRO2 How Haa1 is activated by weak acids is not clear. Here, we show that casein kinase I isoform Hrr25 is an important negative regulator of Haa1. Haa1 is known to be multiply phosphorylated. We found that mutations in HRR25 lead to reduced Haa1 phosphorylation and increased expression of Haa1 target genes and that Hrr25 interacts with Haa1. The other three casein kinase I isoforms, Yck1, Yck2, and Yck3, do not seem to play critical roles in Haa1 regulation. Hrr25 has a 200-residue C-terminal region, including a proline- and glutamine-rich domain. Our data suggest that the C-terminal region of Hrr25 is required for normal inhibition of expression of Haa1 target genes TPO2 and YRO2 and is important for cell growth but is not required for cell morphogenesis. We propose that Hrr25 is an important regulator of cellular adaptation to weak acid stress by inhibiting Haa1 through phosphorylation. IMPORTANCE Our study has revealed the casein kinase I protein Hrr25 to be a negative regulator of Haa1, a transcription factor mediating the cellular response to stresses caused by weak acids. Many studies have focused on the target genes of Haa1 and their roles in weak acid stress responses, but little has been reported on the regulatory mechanism of Haa1. Weak acids, such as acetic acid, have long been used for food preservation by slowing down the growth of fungal species, including S. cerevisiae In the biofuel industry, acetic acid in the lignocellulosic hydrolysates limits the production of ethanol, which is undesirable. By understanding how Haa1 is regulated, we can make advances in the field of food sciences to better preserve food and engineer acetic acid-resistant strains that will increase productivity in the biofuel industry. Copyright © 2017 American Society for Microbiology.

Filament condition-specific response elements control the expression of NRG1 and UME6, key transcriptional regulators of morphology and virulence in Candida albicans.

PubMed

Childers, Delma S; Kadosh, David

2015-01-01

Candida albicans is the most frequently isolated human fungal pathogen and can cause a range of mucosal and systemic infections in immunocompromised individuals. Morphogenesis, the ability to undergo a reversible transition from budding yeast to elongated filaments, is an essential virulence trait. The yeast-to-filament transition is associated with expression of genes specifically important for filamentation as well as other virulence-related processes, and is controlled, in part, by the key transcriptional regulators Nrg1 and Ume6. Both of these regulators are themselves controlled at the transcriptional level by filament-inducing environmental cues, although little is known about how this process occurs. In order to address this question and determine whether environmental signals regulate transcription of UME6 and NRG1 via distinct and/or common promoter elements, we performed promoter deletion analyses. Strains bearing promoter deletion constructs were induced to form filaments in YEPD plus 10% serum at 37°C, Spider medium (nitrogen and carbon starvation) and/or Lee's medium pH 6.8 (neutral pH) and reporter gene expression was measured. In the NRG1 promoter we identified several distinct condition-specific response elements for YEPD plus 10% serum at 37°C and Spider medium. In the UME6 promoter we also identified response elements for YEPD plus 10% serum at 37°C. While a few of these elements are distinct, others overlap with those which respond to Lee's pH 6.8 medium. Consistent with UME6 possessing a very long 5' UTR, many response elements in the UME6 promoter are located significantly upstream from the coding sequence. Our data indicate that certain distinct condition-specific elements can control expression of C. albicans UME6 and NRG1 in response to key filament-inducing environmental cues. Because C. albicans encounters a variety of host microenvironments during infection, our results suggest that UME6 and NRG1 expression can be differentially modulated by multiple signaling pathways to control filamentation and virulence in vivo.

The control of branching morphogenesis

PubMed Central

Iber, Dagmar; Menshykau, Denis

2013-01-01

Many organs of higher organisms are heavily branched structures and arise by an apparently similar process of branching morphogenesis. Yet the regulatory components and local interactions that have been identified differ greatly in these organs. It is an open question whether the regulatory processes work according to a common principle and how far physical and geometrical constraints determine the branching process. Here, we review the known regulatory factors and physical constraints in lung, kidney, pancreas, prostate, mammary gland and salivary gland branching morphogenesis, and describe the models that have been formulated to analyse their impacts. PMID:24004663

Programming Morphogenesis through Systems and Synthetic Biology.

PubMed

Velazquez, Jeremy J; Su, Emily; Cahan, Patrick; Ebrahimkhani, Mo R

2018-04-01

Mammalian tissue development is an intricate, spatiotemporal process of self-organization that emerges from gene regulatory networks of differentiating stem cells. A major goal in stem cell biology is to gain a sufficient understanding of gene regulatory networks and cell-cell interactions to enable the reliable and robust engineering of morphogenesis. Here, we review advances in synthetic biology, single cell genomics, and multiscale modeling, which, when synthesized, provide a framework to achieve the ambitious goal of programming morphogenesis in complex tissues and organoids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Remodeling a tissue: subtraction adds insight.

PubMed

Axelrod, Jeffrey D

2012-11-27

Sculpting a body plan requires both patterning of gene expression and translating that pattern into morphogenesis. Developmental biologists have made remarkable strides in understanding gene expression patterning, but despite a long history of fascination with the mechanics of morphogenesis, knowledge of how patterned gene expression drives the emergence of even simple shapes and forms has grown at a slower pace. The successful merging of approaches from cell biology, developmental biology, imaging, engineering, and mathematical and computational sciences is now accelerating progress toward a fuller and better integrated understanding of the forces shaping morphogenesis.

Functional tooth restoration utilising split germs through re-regionalisation of the tooth-forming field

PubMed Central

Yamamoto, Naomi; Oshima, Masamitsu; Tanaka, Chie; Ogawa, Miho; Nakajima, Kei; Ishida, Kentaro; Moriyama, Keiji; Tsuji, Takashi

2015-01-01

The tooth is an ectodermal organ that arises from a tooth germ under the regulation of reciprocal epithelial-mesenchymal interactions. Tooth morphogenesis occurs in the tooth-forming field as a result of reaction-diffusion waves of specific gene expression patterns. Here, we developed a novel mechanical ligation method for splitting tooth germs to artificially regulate the molecules that control tooth morphology. The split tooth germs successfully developed into multiple correct teeth through the re-regionalisation of the tooth-forming field, which is regulated by reaction-diffusion waves in response to mechanical force. Furthermore, split teeth erupted into the oral cavity and restored physiological tooth function, including mastication, periodontal ligament function and responsiveness to noxious stimuli. Thus, this study presents a novel tooth regenerative technology based on split tooth germs and the re-regionalisation of the tooth-forming field by artificial mechanical force. PMID:26673152

The UV-B Photoreceptor UVR8: From Structure to Physiology

PubMed Central

Jenkins, Gareth I.

2014-01-01

Low doses of UV-B light (280 to 315 nm) elicit photomorphogenic responses in plants that modify biochemical composition, photosynthetic competence, morphogenesis, and defense. UV RESISTANCE LOCUS8 (UVR8) mediates photomorphogenic responses to UV-B by regulating transcription of a set of target genes. UVR8 differs from other known photoreceptors in that it uses specific Trp amino acids instead of a prosthetic chromophore for light absorption during UV-B photoreception. Absorption of UV-B dissociates the UVR8 dimer into monomers, initiating signal transduction through interaction with CONSTITUTIVELY PHOTOMORPHOGENIC1. However, much remains to be learned about the physiological role of UVR8 and its interaction with other signaling pathways, the molecular mechanism of UVR8 photoreception, how the UVR8 protein initiates signaling, how it is regulated, and how UVR8 regulates transcription of its target genes. PMID:24481075

Heart morphogenesis gene regulatory networks revealed by temporal expression analysis.

PubMed

Hill, Jonathon T; Demarest, Bradley; Gorsi, Bushra; Smith, Megan; Yost, H Joseph

2017-10-01

During embryogenesis the heart forms as a linear tube that then undergoes multiple simultaneous morphogenetic events to obtain its mature shape. To understand the gene regulatory networks (GRNs) driving this phase of heart development, during which many congenital heart disease malformations likely arise, we conducted an RNA-seq timecourse in zebrafish from 30 hpf to 72 hpf and identified 5861 genes with altered expression. We clustered the genes by temporal expression pattern, identified transcription factor binding motifs enriched in each cluster, and generated a model GRN for the major gene batteries in heart morphogenesis. This approach predicted hundreds of regulatory interactions and found batteries enriched in specific cell and tissue types, indicating that the approach can be used to narrow the search for novel genetic markers and regulatory interactions. Subsequent analyses confirmed the GRN using two mutants, Tbx5 and nkx2-5 , and identified sets of duplicated zebrafish genes that do not show temporal subfunctionalization. This dataset provides an essential resource for future studies on the genetic/epigenetic pathways implicated in congenital heart defects and the mechanisms of cardiac transcriptional regulation. © 2017. Published by The Company of Biologists Ltd.

A branching morphogenesis program governs embryonic growth of the thyroid gland

PubMed Central

Liang, Shawn; Johansson, Ellen; Barila, Guillermo; Altschuler, Daniel L.; Fagman, Henrik

2018-01-01

ABSTRACT The developmental program that regulates thyroid progenitor cell proliferation is largely unknown. Here, we show that branching-like morphogenesis is a driving force to attain final size of the embryonic thyroid gland in mice. Sox9, a key factor in branching organ development, distinguishes Nkx2-1+ cells in the thyroid bud from the progenitors that originally form the thyroid placode in anterior endoderm. As lobes develop the thyroid primordial tissue branches several generations. Sox9 and Fgfr2b are co-expressed distally in the branching epithelium prior to folliculogenesis. The thyroid in Fgf10 null mutants has a normal shape but is severely hypoplastic. Absence of Fgf10 leads to defective branching and disorganized angiofollicular units although Sox9/Fgfr2b expression and the ability of cells to differentiate and form nascent follicles are not impaired. These findings demonstrate a novel mechanism of thyroid development reminiscent of the Fgf10-Sox9 program that characterizes organogenesis in classical branching organs, and provide clues to aid understanding of how the endocrine thyroid gland once evolved from an exocrine ancestor present in the invertebrate endostyle. PMID:29361553

A branching morphogenesis program governs embryonic growth of the thyroid gland.

PubMed

Liang, Shawn; Johansson, Ellen; Barila, Guillermo; Altschuler, Daniel L; Fagman, Henrik; Nilsson, Mikael

2018-01-25

The developmental program that regulates thyroid progenitor cell proliferation is largely unknown. Here, we show that branching-like morphogenesis is a driving force to attain final size of the embryonic thyroid gland in mice. Sox9, a key factor in branching organ development, distinguishes Nkx2-1 + cells in the thyroid bud from the progenitors that originally form the thyroid placode in anterior endoderm. As lobes develop the thyroid primordial tissue branches several generations. Sox9 and Fgfr2b are co-expressed distally in the branching epithelium prior to folliculogenesis. The thyroid in Fgf10 null mutants has a normal shape but is severely hypoplastic. Absence of Fgf10 leads to defective branching and disorganized angiofollicular units although Sox9/Fgfr2b expression and the ability of cells to differentiate and form nascent follicles are not impaired. These findings demonstrate a novel mechanism of thyroid development reminiscent of the Fgf10-Sox9 program that characterizes organogenesis in classical branching organs, and provide clues to aid understanding of how the endocrine thyroid gland once evolved from an exocrine ancestor present in the invertebrate endostyle. © 2018. Published by The Company of Biologists Ltd.

In vivo genome-wide analysis of multiple tissues identifies gene regulatory networks, novel functions and downstream regulatory genes for Bapx1 and its co-regulation with Sox9 in the mammalian vertebral column.

PubMed

Chatterjee, Sumantra; Sivakamasundari, V; Yap, Sook Peng; Kraus, Petra; Kumar, Vibhor; Xing, Xing; Lim, Siew Lan; Sng, Joel; Prabhakar, Shyam; Lufkin, Thomas

2014-12-05

Vertebrate organogenesis is a highly complex process involving sequential cascades of transcription factor activation or repression. Interestingly a single developmental control gene can occasionally be essential for the morphogenesis and differentiation of tissues and organs arising from vastly disparate embryological lineages. Here we elucidated the role of the mammalian homeobox gene Bapx1 during the embryogenesis of five distinct organs at E12.5 - vertebral column, spleen, gut, forelimb and hindlimb - using expression profiling of sorted wildtype and mutant cells combined with genome wide binding site analysis. Furthermore we analyzed the development of the vertebral column at the molecular level by combining transcriptional profiling and genome wide binding data for Bapx1 with similarly generated data sets for Sox9 to assemble a detailed gene regulatory network revealing genes previously not reported to be controlled by either of these two transcription factors. The gene regulatory network appears to control cell fate decisions and morphogenesis in the vertebral column along with the prevention of premature chondrocyte differentiation thus providing a detailed molecular view of vertebral column development.

RhoA GTPase inhibition organizes contraction during epithelial morphogenesis

PubMed Central

Mason, Frank M.; Xie, Shicong; Vasquez, Claudia G.; Tworoger, Michael

2016-01-01

During morphogenesis, contraction of the actomyosin cytoskeleton within individual cells drives cell shape changes that fold tissues. Coordination of cytoskeletal contractility is mediated by regulating RhoA GTPase activity. Guanine nucleotide exchange factors (GEFs) activate and GTPase-activating proteins (GAPs) inhibit RhoA activity. Most studies of tissue folding, including apical constriction, have focused on how RhoA is activated by GEFs to promote cell contractility, with little investigation as to how GAPs may be important. Here, we identify a critical role for a RhoA GAP, Cumberland GAP (C-GAP), which coordinates with a RhoA GEF, RhoGEF2, to organize spatiotemporal contractility during Drosophila melanogaster apical constriction. C-GAP spatially restricts RhoA pathway activity to a central position in the apical cortex. RhoGEF2 pulses precede myosin, and C-GAP is required for pulsation, suggesting that contractile pulses result from RhoA activity cycling. Finally, C-GAP expression level influences the transition from reversible to irreversible cell shape change, which defines the onset of tissue shape change. Our data demonstrate that RhoA activity cycling and modulating the ratio of RhoGEF2 to C-GAP are required for tissue folding. PMID:27551058

A Novel Predicted Bromodomain-Related Protein Affects Coordination Between Meiosis and Spermiogenesis in Drosophila and Is Required for Male Meiotic Cytokinesis

PubMed Central

Bergner, Laura M.; Hickman, F. Edward; Wood, Kathleen H.; Wakeman, Carolyn M.; Stone, Hunter H.; Campbell, Tessa J.; Lightcap, Samantha B.; Favors, Sheena M.; Aldridge, Amanda C.

2010-01-01

Temporal coordination of meiosis with spermatid morphogenesis is crucial for successful generation of mature sperm cells. We identified a recessive male sterile Drosophila melanogaster mutant, mitoshell, in which events of spermatid morphogenesis are initiated too early, before meiotic onset. Premature mitochondrial aggregation and fusion lead to an aberrant mitochondrial shell around premeiotic nuclei. Despite successful meiotic karyokinesis, improper mitochondrial localization in mitoshell testes is associated with defective astral central spindles and a lack of contractile rings, leading to meiotic cytokinesis failure. We mapped and cloned the mitoshell gene and found that it encodes a novel protein with a bromodomain-related region. It is conserved in some insect lineages. Bromodomains typically bind to histone acetyl-lysine residues and therefore are often associated with chromatin. The Mitoshell bromodomain-related region is predicted to have an alpha helical structure similar to that of bromodomains, but not all the crucial residues in the ligand-binding loops are conserved. We speculate that Mitoshell may participate in transcriptional regulation of spermatogenesis-specific genes, though perhaps with different ligand specificity compared to traditional bromodomains. PMID:20491580

MpWIP regulates air pore complex development in the liverwort Marchantia polymorpha.

PubMed

Jones, Victor A S; Dolan, Liam

2017-04-15

The colonisation of the land by plants was accompanied by the evolution of complex tissues and multicellular structures comprising different cell types as morphological adaptations to the terrestrial environment. Here, we show that the single WIP protein in the early-diverging land plant Marchantia polymorpha L. is required for the development of the multicellular gas exchange structure: the air pore complex. This 16-cell barrel-shaped structure surrounds an opening between epidermal cells that facilitates the exchange of gases between the chamber containing the photosynthetic cells inside the plant and the air outside. Mp WIP is expressed in cells of the developing air pore complex and the morphogenesis of the complex is defective in plants with reduced Mp WIP function. The role of WIP proteins in the control of different multicellular structures in M. polymorpha and the flowering plant Arabidopsis thaliana suggests that these proteins controlled the development of multicellular structures in the common ancestor of land plants. We hypothesise that WIP genes were subsequently co-opted in the control of morphogenesis of novel multicellular structures that evolved during the diversification of land plants. © 2017. Published by The Company of Biologists Ltd.

The AMPA receptor subunit GluR1 regulates dendritic architecture of motor neurons

NASA Technical Reports Server (NTRS)

Inglis, Fiona M.; Crockett, Richard; Korada, Sailaja; Abraham, Wickliffe C.; Hollmann, Michael; Kalb, Robert G.

2002-01-01

The morphology of the mature motor neuron dendritic arbor is determined by activity-dependent processes occurring during a critical period in early postnatal life. The abundance of the AMPA receptor subunit GluR1 in motor neurons is very high during this period and subsequently falls to a negligible level. To test the role of GluR1 in dendrite morphogenesis, we reintroduced GluR1 into rat motor neurons at the end of the critical period and quantitatively studied the effects on dendrite architecture. Two versions of GluR1 were studied that differed by the amino acid in the "Q/R" editing site. The amino acid occupying this site determines single-channel conductance, ionic permeability, and other essential electrophysiologic properties of the resulting receptor channels. We found large-scale remodeling of dendritic architectures in a manner depending on the amino acid occupying the Q/R editing site. Alterations in the distribution of dendritic arbor were not prevented by blocking NMDA receptors. These observations suggest that the expression of GluR1 in motor neurons modulates a component of the molecular substrate of activity-dependent dendrite morphogenesis. The control of these events relies on subunit-specific properties of AMPA receptors.

Automated Image Analysis of Lung Branching Morphogenesis from Microscopic Images of Fetal Rat Explants

PubMed Central

Rodrigues, Pedro L.; Rodrigues, Nuno F.; Duque, Duarte; Granja, Sara; Correia-Pinto, Jorge; Vilaça, João L.

2014-01-01

Background. Regulating mechanisms of branching morphogenesis of fetal lung rat explants have been an essential tool for molecular research. This work presents a new methodology to accurately quantify the epithelial, outer contour, and peripheral airway buds of lung explants during cellular development from microscopic images. Methods. The outer contour was defined using an adaptive and multiscale threshold algorithm whose level was automatically calculated based on an entropy maximization criterion. The inner lung epithelium was defined by a clustering procedure that groups small image regions according to the minimum description length principle and local statistical properties. Finally, the number of peripheral buds was counted as the skeleton branched ends from a skeletonized image of the lung inner epithelia. Results. The time for lung branching morphometric analysis was reduced in 98% in contrast to the manual method. Best results were obtained in the first two days of cellular development, with lesser standard deviations. Nonsignificant differences were found between the automatic and manual results in all culture days. Conclusions. The proposed method introduces a series of advantages related to its intuitive use and accuracy, making the technique suitable to images with different lighting characteristics and allowing a reliable comparison between different researchers. PMID:25250057

The control of fruiting body formation in the ascomycete Sordaria macrospora Auersw. by regulation of hyphal development : An analysis based on scanning electron and light microscopic observations.

PubMed

Hock, B; Bahn, M; Walk, R A; Nitschke, U

1978-01-01

The morphological effects of biotin and L-arginine on fruiting body formation of the ascomycete Sordaria macrospora are investigated by scanning electron and light microscopy. Biotin is recognized as an elongation factor and arginine as a branching factor in vegetative and reproductive hyphae. In the absence of exogenous biotin, development is blocked after the ascogonium-core hypha stage of protoperithecial morphogenesis, whereas linear growth of the myceliar front is maintained. The addition of exogenous arginine to a biotin deficient culture induces the formation of numerous side branches even in the older mycelium. Fruiting body formation, however, remains blocked at the protoperithecial stage as before, because of the inability of the side branches to elongate. When biotin and arginine are administered simultaneously, a most vigorous branching and growth are induced in the older mycelium, accompanied by a rapid and maximal formation of fruiting bodies. The results are summarized in a model of the exogenous control of hyphal morphogenesis. The model is designed to explain the relationship between fruiting and hyphal density as well as the edge effect on fruiting body formation.

Stem/Progenitor Cell Proteoglycans Decorated with 7-D-4, 4-C-3 and 3-B-3(-) Chondroitin Sulphate Motifs Are Morphogenetic Markers Of Tissue Development.

PubMed

Hayes, Anthony J; Smith, Susan M; Caterson, Bruce; Melrose, James

2018-06-11

This study reviewed the occurrence of chondroitin sulphate (CS) motifs 4-C-3, 7-D-4 and 3-B-3(-) which are expressed by progenitor cells in tissues undergoing morphogenesis. These motifs have a transient early expression pattern during tissue development and also appear in mature tissues during pathological remodeling and attempted repair processes by activated adult stem cells. The CS motifs are information and recognition modules, which may regulate cellular behavior and delineate stem cell niches in developmental tissues. One of the difficulties in determining the precise role of stem cells in tissue development and repair processes is their short engraftment period and the lack of specific markers, which differentiate the activated stem cell lineages from the resident cells. The CS sulphation motifs 7-D-4, 4-C-3 and 3-B-3 (-) decorate cell surface proteoglycans on activated stem/progenitor cells and appear to identify these cells in transitional areas of tissue development and in tissue repair and may be applicable to determining a more precise role for stem cells in tissue morphogenesis. This article is protected by copyright. All rights reserved. © 2018 AlphaMed Press.

Robustness in Regulatory Interaction Networks. A Generic Approach with Applications at Different Levels: Physiologic, Metabolic and Genetic

PubMed Central

Demongeot, Jacques; Ben Amor, Hedi; Elena, Adrien; Gillois, Pierre; Noual, Mathilde; Sené, Sylvain

2009-01-01

Regulatory interaction networks are often studied on their dynamical side (existence of attractors, study of their stability). We focus here also on their robustness, that is their ability to offer the same spatiotemporal patterns and to resist to external perturbations such as losses of nodes or edges in the networks interactions architecture, changes in their environmental boundary conditions as well as changes in the update schedule (or updating mode) of the states of their elements (e.g., if these elements are genes, their synchronous coexpression mode versus their sequential expression). We define the generic notions of boundary, core, and critical vertex or edge of the underlying interaction graph of the regulatory network, whose disappearance causes dramatic changes in the number and nature of attractors (e.g., passage from a bistable behaviour to a unique periodic regime) or in the range of their basins of stability. The dynamic transition of states will be presented in the framework of threshold Boolean automata rules. A panorama of applications at different levels will be given: brain and plant morphogenesis, bulbar cardio-respiratory regulation, glycolytic/oxidative metabolic coupling, and eventually cell cycle and feather morphogenesis genetic control. PMID:20057955

Perithecium morphogenesis in Sordaria macrospora.

PubMed

Lord, Kathryn M; Read, Nick D

2011-04-01

The perithecium of the self-fertile ascomycete Sordaria macrospora provides an excellent model in which to analyse fungal multicellular development. This study provides a detailed analysis of perithecium morphogenesis in the wild type and eight developmental mutants of S. macrospora, using a range of correlative microscopical techniques. Fundamentally, perithecia and other complex multicellular structures produced by fungi arise by hyphal aggregation and adhesion, and these processes are followed by specialization and septation of hyphal compartments within the aggregates. Perithecial morphogenesis can be divided into the ascogonial, protoperithecial, and perithecial stages of development. At least 13 specialized, morphologically distinct cell-types are involved in perithecium morphogenesis, and these fall into three basic classes: hyphae, conglutinate cells and spores. Conglutinate cells arise from hyphal adhesion and certain perithecial hyphae develop from conglutinate cells. Various hypha-conglutinate cell transitions play important roles during the development of the perithecial wall and neck. Copyright © 2010. Published by Elsevier Inc.

Developmental Control of Cell-Cycle Compensation Provides a Switch for Patterned Mitosis at the Onset of Chordate Neurulation.

PubMed

Ogura, Yosuke; Sasakura, Yasunori

2016-04-18

During neurulation of chordate ascidians, the 11th mitotic division within the epidermal layer shows a posterior-to-anterior wave that is precisely coordinated with the unidirectional progression of the morphogenetic movement. Here we show that the first sign of this patterned mitosis is an asynchronous anterior-to-posterior S-phase length and that mitotic synchrony is reestablished by a compensatory asynchronous G2-phase length. Live imaging combined with genetic experiments demonstrated that compensatory G2-phase regulation requires transcriptional activation of the G2/M regulator cdc25 by the patterning genes GATA and AP-2. The downregulation of GATA and AP-2 at the onset of neurulation leads to loss of compensatory G2-phase regulation and promotes the transition to patterned mitosis. We propose that such developmentally regulated cell-cycle compensation provides an abrupt switch to spatially patterned mitosis in order to achieve the coordination between mitotic timing and morphogenesis. Copyright © 2016 Elsevier Inc. All rights reserved.

The Drosophila actin regulator ENABLED regulates cell shape and orientation during gonad morphogenesis.

PubMed

Sano, Hiroko; Kunwar, Prabhat S; Renault, Andrew D; Barbosa, Vitor; Clark, Ivan B N; Ishihara, Shuji; Sugimura, Kaoru; Lehmann, Ruth

2012-01-01

Organs develop distinctive morphologies to fulfill their unique functions. We used Drosophila embryonic gonads as a model to study how two different cell lineages, primordial germ cells (PGCs) and somatic gonadal precursors (SGPs), combine to form one organ. We developed a membrane GFP marker to image SGP behaviors live. These studies show that a combination of SGP cell shape changes and inward movement of anterior and posterior SGPs leads to the compaction of the spherical gonad. This process is disrupted in mutants of the actin regulator, enabled (ena). We show that Ena coordinates these cell shape changes and the inward movement of the SGPs, and Ena affects the intracellular localization of DE-cadherin (DE-cad). Mathematical simulation based on these observations suggests that changes in DE-cad localization can generate the forces needed to compact an elongated structure into a sphere. We propose that Ena regulates force balance in the SGPs by sequestering DE-cad, leading to the morphogenetic movement required for gonad compaction.

Laminin Levels Regulate Tissue Migration and Anterior-Posterior Polarity during Egg Morphogenesis in Drosophila.

PubMed

Díaz de la Loza, María C; Díaz-Torres, Alfonsa; Zurita, Federico; Rosales-Nieves, Alicia E; Moeendarbary, Emad; Franze, Kristian; Martín-Bermudo, María D; González-Reyes, Acaimo

2017-07-05

Basement membranes (BMs) are specialized extracellular matrices required for tissue organization and organ formation. We study the role of laminin and its integrin receptor in the regulation of tissue migration during Drosophila oogenesis. Egg production in Drosophila involves the collective migration of follicle cells (FCs) over the BM to shape the mature egg. We show that laminin content in the BM increases with time, whereas integrin amounts in FCs do not vary significantly. Manipulation of integrin and laminin levels reveals that a dynamic balance of integrin-laminin amounts determines the onset and speed of FC migration. Thus, the interplay of ligand-receptor levels regulates tissue migration in vivo. Laminin depletion also affects the ultrastructure and biophysical properties of the BM and results in anterior-posterior misorientation of developing follicles. Laminin emerges as a key player in the regulation of collective cell migration, tissue stiffness, and the organization of anterior-posterior polarity in Drosophila. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Complex Interdependence Regulates Heterotypic Transcription Factor Distribution and Coordinates Cardiogenesis.

PubMed

Luna-Zurita, Luis; Stirnimann, Christian U; Glatt, Sebastian; Kaynak, Bogac L; Thomas, Sean; Baudin, Florence; Samee, Md Abul Hassan; He, Daniel; Small, Eric M; Mileikovsky, Maria; Nagy, Andras; Holloway, Alisha K; Pollard, Katherine S; Müller, Christoph W; Bruneau, Benoit G

2016-02-25

Transcription factors (TFs) are thought to function with partners to achieve specificity and precise quantitative outputs. In the developing heart, heterotypic TF interactions, such as between the T-box TF TBX5 and the homeodomain TF NKX2-5, have been proposed as a mechanism for human congenital heart defects. We report extensive and complex interdependent genomic occupancy of TBX5, NKX2-5, and the zinc finger TF GATA4 coordinately controlling cardiac gene expression, differentiation, and morphogenesis. Interdependent binding serves not only to co-regulate gene expression but also to prevent TFs from distributing to ectopic loci and activate lineage-inappropriate genes. We define preferential motif arrangements for TBX5 and NKX2-5 cooperative binding sites, supported at the atomic level by their co-crystal structure bound to DNA, revealing a direct interaction between the two factors and induced DNA bending. Complex interdependent binding mechanisms reveal tightly regulated TF genomic distribution and define a combinatorial logic for heterotypic TF regulation of differentiation. Copyright © 2016 Elsevier Inc. All rights reserved.

Human Development VI: Supracellular Morphogenesis. The Origin of Biological and Cellular Order

PubMed Central

Ventegodt, Søren; Hermansen, Tyge Dahl; Flensborg-Madsen, Trine; Nielsen, Maj Lyck; Merrick, Joav

2006-01-01

Uninterrupted morphogenesis shows the informational potentials of biological organisms. Experimentally disturbed morphogenesis shows the compensational dynamics of the biological informational system, which is the rich informational redundancy. In this paper, we use these data to describe morphogenesis in terms of the development of supracellular levels of the organism, and we define complex epigenesis and supracellular differentiation. We review the phenomena of regeneration and induction of Hydra and amphibians, and the higher animals informational needs for developing their complex nervous systems. We argue, also building on the NO-GO theorem for ontogenesis as chemistry, that the traditional chemical explanations of high-level informational events in ontogenesis, such as transmutation, regeneration, and induction, are insufficient. We analyze the informational dynamics of three embryonic compensatory reactions to different types of disturbances: (1) transmutations of the imaginal discs of insects, (2) regeneration after removal of embryonic tissue, and (3) embryonic induction, where two tissues that normally are separated experimentally are made to influence each other. We describe morphogenesis as a complex bifurcation, and the resulting morphological levels of the organism as organized in a fractal manner and supported by positional information. We suggest that some kind of real nonchemical phenomenon must be taking form in living organisms as an information-carrying dynamic fractal field, causing morhogenesis and supporting the organisms morphology through time. We argue that only such a phenomenon that provides information-directed self-organization to the organism is able to explain the observed dynamic distribution of biological information through morphogenesis and the organism's ability to rejuvenate and heal. PMID:17115082

Direct activation of Shroom3 transcription by Pitx proteins drives epithelial morphogenesis in the developing gut

PubMed Central

Chung, Mei-I; Nascone-Yoder, Nanette M.; Grover, Stephanie A.; Drysdale, Thomas A.; Wallingford, John B.

2010-01-01

Individual cell shape changes are essential for epithelial morphogenesis. A transcriptional network for epithelial cell shape change is emerging in Drosophila, but this area remains largely unexplored in vertebrates. The distinction is important as so far, key downstream effectors of cell shape change in Drosophila appear not to be conserved. Rather, Shroom3 has emerged as a central effector of epithelial morphogenesis in vertebrates, driving both actin- and microtubule-based cell shape changes. To date, the morphogenetic role of Shroom3 has been explored only in the neural epithelium, so the broad expression of this gene raises two important questions: what are the requirements for Shroom3 in non-neural tissues and what factors control Shroom3 transcription? Here, we show in Xenopus that Shroom3 is essential for cell shape changes and morphogenesis in the developing vertebrate gut and that Shroom3 transcription in the gut requires the Pitx1 transcription factor. Moreover, we show that Pitx proteins directly activate Shroom3 transcription, and we identify Pitx-responsive regulatory elements in the genomic DNA upstream of Shroom3. Finally, we show that ectopic expression of Pitx proteins is sufficient to induce Shroom3-dependent cytoskeletal reorganization and epithelial cell shape change. These data demonstrate new breadth to the requirements for Shroom3 in morphogenesis, and they also provide a cell-biological basis for the role of Pitx transcription factors in morphogenesis. More generally, these results provide a foundation for deciphering the transcriptional network that underlies epithelial cell shape change in developing vertebrates. PMID:20332151

Fibronectin Deposition Participates in Extracellular Matrix Assembly and Vascular Morphogenesis

PubMed Central

Hielscher, Abigail; Ellis, Kim; Qiu, Connie; Porterfield, Josh; Gerecht, Sharon

2016-01-01

The extracellular matrix (ECM) has been demonstrated to facilitate angiogenesis. In particular, fibronectin has been documented to activate endothelial cells, resulting in their transition from a quiescent state to an active state in which the cells exhibit enhanced migration and proliferation. The goal of this study is to examine the role of polymerized fibronectin during vascular tubulogenesis using a 3 dimensional (3D) cell-derived de-cellularized matrix. A fibronectin-rich 3D de-cellularized ECM was used as a scaffold to study vascular morphogenesis of endothelial cells (ECs). Confocal analyses of several matrix proteins reveal high intra- and extra-cellular deposition of fibronectin in formed vascular structures. Using a small peptide inhibitor of fibronectin polymerization, we demonstrate that inhibition of fibronectin fibrillogenesis in ECs cultured atop de-cellularized ECM resulted in decreased vascular morphogenesis. Further, immunofluorescence and ultrastructural analyses reveal decreased expression of stromal matrix proteins in the absence of polymerized fibronectin with high co-localization of matrix proteins found in association with polymerized fibronectin. Evaluating vascular kinetics, live cell imaging showed that migration, migration velocity, and mean square displacement, are disrupted in structures grown in the absence of polymerized fibronectin. Additionally, vascular organization failed to occur in the absence of a polymerized fibronectin matrix. Consistent with these observations, we tested vascular morphogenesis following the disruption of EC adhesion to polymerized fibronectin, demonstrating that block of integrins α5β1 and αvβ3, abrogated vascular morphogenesis. Overall, fibronectin deposition in a 3D cell-derived de-cellularized ECM appears to be imperative for matrix assembly and vascular morphogenesis. PMID:26811931

β-lapachone and α-nor-lapachone modulate Candida albicans viability and virulence factors.

PubMed

Moraes, D C; Curvelo, J A R; Anjos, C A; Moura, K C G; Pinto, M C F R; Portela, M B; Soares, R M A

2018-03-26

Candida albicans is the most important fungal pathogen that causes infections in humans, and the search for new therapeutic strategies for its treatment is essential. The aim of this study was to evaluate the activity of seven naphthoquinones (β-lapachone, β-nor-lapachone, bromide-β-lapachone, hydroxy-β-lapachone, α-lapachone, α-nor-lapachone and α-xyloidone) on the growth of a fluconazole-resistant C. albicans oral clinical isolate and the effects of these compounds on the viability of mammalian cells, on yeast's morphogenesis, biofilm formation and cell wall mannoproteins availability. All the compounds were able to completely inhibit the yeast growth. β-lapachone and α-nor-lapachone were the less cytotoxic compounds against L929 and RAW 264.7 cells. At IC 50 , β-lapachone inhibited morphogenesis in 92%, while the treatment of yeast cells with α-nor-lapachone decreased yeast-to-hyphae transition in 42%. At 50μg/ml, β-lapachone inhibited biofilm formation by 84%, whereas α-nor-lapachone reduced biofilm formation by 64%. The treatment of yeast cells with β-lapachone decreased cell wall mannoproteins availability in 28.5%, while α-nor-lapachone was not able to interfere on this virulence factor. Taken together, data show that β-lapachone and α-nor-lapachone exhibited in vitro cytotoxicity against a fluconazole-resistant C. albicans strain, thus demonstrating to be promising candidates to be used in the treatment of infections caused by this fungus. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Specific serine-proline phosphorylation and glycogen synthase kinase 3β-directed subcellular targeting of stathmin 3/Sclip in neurons.

PubMed

Devaux, Sara; Poulain, Fabienne E; Devignot, Véronique; Lachkar, Sylvie; Irinopoulou, Theano; Sobel, André

2012-06-22

During nervous system development, neuronal growth, migration, and functional morphogenesis rely on the appropriate control of the subcellular cytoskeleton including microtubule dynamics. Stathmin family proteins play major roles during the various stages of neuronal differentiation, including axonal growth and branching, or dendritic development. We have shown previously that stathmins 2 (SCG10) and 3 (SCLIP) fulfill distinct, independent and complementary regulatory roles in axonal morphogenesis. Although the two proteins have been proposed to display the four conserved phosphorylation sites originally identified in stathmin 1, we show here that they possess distinct phosphorylation sites within their specific proline-rich domains (PRDs) that are differentially regulated by phosphorylation by proline-directed kinases involved in the control of neuronal differentiation. ERK2 or CDK5 phosphorylate the two proteins but with different site specificities. We also show for the first time that, unlike stathmin 2, stathmin 3 is a substrate for glycogen synthase kinase (GSK) 3β both in vitro and in vivo. Interestingly, stathmin 3 phosphorylated at its GSK-3β target site displays a specific subcellular localization at neuritic tips and within the actin-rich peripheral zone of the growth cone of differentiating hippocampal neurons in culture. Finally, pharmacological inhibition of GSK-3β induces a redistribution of stathmin 3, but not stathmin 2, from the periphery toward the Golgi region of neurons. Stathmin proteins can thus be either regulated locally or locally targeted by specific phosphorylation, each phosphoprotein of the stathmin family fulfilling distinct and specific roles in the control of neuronal differentiation.

β-Catenin signaling regulates temporally discrete phases of anterior taste bud development.

PubMed

Thirumangalathu, Shoba; Barlow, Linda A

2015-12-15

The sense of taste is mediated by multicellular taste buds located within taste papillae on the tongue. In mice, individual taste buds reside in fungiform papillae, which develop at mid-gestation as epithelial placodes in the anterior tongue. Taste placodes comprise taste bud precursor cells, which express the secreted factor sonic hedgehog (Shh) and give rise to taste bud cells that differentiate around birth. We showed previously that epithelial activation of β-catenin is the primary inductive signal for taste placode formation, followed by taste papilla morphogenesis and taste bud differentiation, but the degree to which these later elements were direct or indirect consequences of β-catenin signaling was not explored. Here, we define discrete spatiotemporal functions of β-catenin in fungiform taste bud development. Specifically, we show that early epithelial activation of β-catenin, before taste placodes form, diverts lingual epithelial cells from a taste bud fate. By contrast, β-catenin activation a day later within Shh(+) placodes, expands taste bud precursors directly, but enlarges papillae indirectly. Further, placodal activation of β-catenin drives precocious differentiation of Type I glial-like taste cells, but not other taste cell types. Later activation of β-catenin within Shh(+) precursors during papilla morphogenesis also expands taste bud precursors and accelerates Type I cell differentiation, but papilla size is no longer enhanced. Finally, although Shh regulates taste placode patterning, we find that it is dispensable for the accelerated Type I cell differentiation induced by β-catenin. © 2015. Published by The Company of Biologists Ltd.

ARABIDOPSIS HOMOLOG of TRITHORAX1 (ATX1) is required for cell production, patterning, and morphogenesis in root development

PubMed Central

Napsucialy-Mendivil, Selene; Alvarez-Venegas, Raúl; Shishkova, Svetlana; Dubrovsky, Joseph G.

2014-01-01

ARABIDOPSIS HOMOLOG of TRITHORAX1 (ATX1/SDG27), a known regulator of flower development, encodes a H3K4histone methyltransferase that maintains a number of genes in an active state. In this study, the role of ATX1 in root development was evaluated. The loss-of-function mutant atx1-1 was impaired in primary root growth. The data suggest that ATX1 controls root growth by regulating cell cycle duration, cell production, and the transition from cell proliferation in the root apical meristem (RAM) to cell elongation. In atx1-1, the quiescent centre (QC) cells were irregular in shape and more expanded than those of the wild type. This feature, together with the atypical distribution of T-divisions, the presence of oblique divisions, and the abnormal cell patterning in the RAM, suggests a lack of coordination between cell division and cell growth in the mutant. The expression domain of QC-specific markers was expanded both in the primary RAM and in the developing lateral root primordia of atx1-1 plants. These abnormalities were independent of auxin-response gradients. ATX1 was also found to be required for lateral root initiation, morphogenesis, and emergence. The time from lateral root initiation to emergence was significantly extended in the atx1-1 mutant. Overall, these data suggest that ATX1 is involved in the timing of root development, stem cell niche maintenance, and cell patterning during primary and lateral root development. Thus, ATX1 emerges as an important player in root system architecture. PMID:25205583

Limonene inhibits Candida albicans growth by inducing apoptosis.

PubMed

Thakre, Archana; Zore, Gajanan; Kodgire, Santosh; Kazi, Rubina; Mulange, Shradha; Patil, Rajendra; Shelar, Amruta; Santhakumari, Bayitigeri; Kulkarni, Mahesh; Kharat, Kiran; Karuppayil, Sankunny Mohan

2018-07-01

Anti-Candida potential of limonene was evaluated against planktonic growth, biofilm (adhesion, development and maturation) and morphogenesis of Candida albicans in this study. Limonene is a major constituent of citrus oil and most frequently used terpene in food and beverage industry due to its pleasant fragrance, nontoxic, and is generally recognized as safe (GRAS) flavoring agent as well as treatment option in many gastrointestinal diseases.Limonene exhibited excellent anti-Candida activity and was equally effective against planktonic growth of C. albicans isolates differentially susceptible to FLC (N = 35). Limonene inhibited morphogenesis significantly at low concentration. However, it showed stage dependent activity against biofilm formation, that is, it was more effective against adhesion followed by development and maturation. Limonene also exhibited excellent synergy with FLC against planktonic and biofilm growth. SWATH-MS analysis led to identification of limonene responsive proteins that provided molecular insight of its anti-Candida activity. Proteomic analysis revealed upregulation of proteins involved in cell wall glucan synthesis (Kre6); oxidative stress (Rhr2, Adh7 and Ebp1); DNA damage stress (Mbf1 and Npl3); nucleolar stress (Rpl11, Rpl7, Rpl29, Rpl15) and down regulation of cytoskeleton organization (Crn1, Pin3, Cct8, Rbl2), and so forth, in response to limonene. Limonene mediated down regulation of Tps3 indicates activation of caspase (CaMca1) and induction of apoptosis in C. albicans. These results suggest that limonene inhibits C. albicans growth by cell wall/membrane damage induced oxidative stress that leads to DNA damage resulting into modulation of cell cycle and induction of apoptosis through nucleolar stress and metacaspase dependent pathway.

Notch3 Signaling-Mediated Melanoma-Endothelial Crosstalk Regulates Melanoma Stem-Like Cell Homeostasis and Niche Morphogenesis

PubMed Central

Hsu, Mei-Yu; Yang, Moon Hee; Schnegg, Caroline I.; Hwang, Soonyean; Ryu, Byungwoo; Alani, Rhoda M.

2016-01-01

Melanoma is among the most virulent cancers, owing to its propensity to metastasize and its resistance to current therapies. The treatment failure is largely attributed to tumor heterogeneity, particularly subpopulations possessing stem cell-like properties, i.e., melanoma stem-like cells (MSLCs). Evidence indicates that the MSLC phenotype is malleable and may be acquired by non-MSLCs through phenotypic switching upon appropriate stimuli, the so–called “dynamic stemness”. Since the phenotypic characteristics and functional integrity of MSLCs depend on their vascular niche, using a two dimensional (2D) melanoma-endothelium co-culture model, where the MSLC niche is recapitulated in vitro, we identified Notch3 signaling pathway as a micro-environmental cue governing MSLC phenotypic plasticity via pathway-specific gene expression arrays. Accordingly, lentiviral shRNA-mediated Notch3 knockdown (KD) in melanoma cell lines exhibiting high levels of endogenous Notch3 led to retarded/abolished tumorigenicity in vivo through both depleting MSLC fractions, evinced by MSLC marker down-regulation (e.g., CD133 and CD271); and impeding the MSLC niche, corroborated by the attenuated tumor angiogenesis as well as vasculogenic mimicry. In contrast, Notch3 KD affected neither tumor growth nor MSLC subsets in a melanoma cell line with relatively low endogenous Notch3 expression. Thus, Notch3 signaling may facilitate MSLC plasticity and niche morphogenesis in a cell context-dependent fashion. Our findings illustrate Notch3 as a molecular switch driving melanoma heterogeneity, and provide the biological rationale for Notch inhibition as a promising therapeutic option. PMID:28165469

Cell-cell and cell-extracellular matrix adhesions cooperate to organize actomyosin networks and maintain force transmission during dorsal closure.

PubMed

Goodwin, Katharine; Lostchuck, Emily E; Cramb, Kaitlyn M L; Zulueta-Coarasa, Teresa; Fernandez-Gonzalez, Rodrigo; Tanentzapf, Guy

2017-05-15

Tissue morphogenesis relies on the coordinated action of actin networks, cell-cell adhesions, and cell-extracellular matrix (ECM) adhesions. Such coordination can be achieved through cross-talk between cell-cell and cell-ECM adhesions. Drosophila dorsal closure (DC), a morphogenetic process in which an extraembryonic tissue called the amnioserosa contracts and ingresses to close a discontinuity in the dorsal epidermis of the embryo, requires both cell-cell and cell-ECM adhesions. However, whether the functions of these two types of adhesions are coordinated during DC is not known. Here we analyzed possible interdependence between cell-cell and cell-ECM adhesions during DC and its effect on the actomyosin network. We find that loss of cell-ECM adhesion results in aberrant distributions of cadherin-mediated adhesions and actin networks in the amnioserosa and subsequent disruption of myosin recruitment and dynamics. Moreover, loss of cell-cell adhesion caused up-regulation of cell-ECM adhesion, leading to reduced cell deformation and force transmission across amnioserosa cells. Our results show how interdependence between cell-cell and cell-ECM adhesions is important in regulating cell behaviors, force generation, and force transmission critical for tissue morphogenesis. © 2017 Goodwin, Lostchuck, et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Solo and keratin filaments regulate epithelial tubule morphology.

PubMed

Nishimura, Ryosuke; Kato, Kagayaki; Fujiwara, Sachiko; Ohashi, Kazumasa; Mizuno, Kensaku

2018-04-28

Epithelial tubules, consisting of the epithelial cell sheet with a central lumen, are the basic structure of many organs. Mechanical forces play an important role in epithelial tubulogenesis; however, little is known about the mechanisms controlling the mechanical forces during epithelial tubule morphogenesis. Solo (also known as ARHGEF40) is a RhoA-targeting guanine-nucleotide exchange factor that is involved in mechanical force-induced RhoA activation and stress fiber formation. Solo binds to keratin-8/keratin-18 (K8/K18) filaments, and this interaction plays a crucial role in mechanotransduction. In this study, we examined the roles of Solo and K8/K18 filaments in epithelial tubulogenesis using MDCK cells cultured in 3D collagen gels. Knockdown of either Solo or K18 resulted in rounder tubules with increased lumen size, indicating that Solo and K8/K18 filaments play critical roles in forming the elongated morphology of epithelial tubules. Moreover, knockdown of Solo or K18 decreased the level of diphosphorylated myosin light chain (a marker of contractile force) at the luminal and outer surfaces of tubules, suggesting that Solo and K8/K18 filaments are involved in the generation of the myosin II-mediated contractile force during epithelial tubule morphogenesis. In addition, K18 filaments were normally oriented along the long axis of the tubule, but knockdown of Solo perturbed their orientation. These results suggest that Solo plays crucial roles in forming the elongated morphology of epithelial tubules and in regulating myosin II activity and K18 filament organization during epithelial tubule formation.

Active Cellular Mechanics and its Consequences for Animal Development

NASA Astrophysics Data System (ADS)

Noll, Nicholas B.

A central goal of developmental biology is to understand how an organism shapes itself, a process referred to as morphogenesis. While the molecular components critical to determining the initial body plan have been well characterized, the control of the subsequent dynamics of cellular rearrangements which ultimately shape the organism are far less understood. A major roadblock to a more complete picture of morphogenesis is the inability to measure tissue-scale mechanics throughout development and thus answer fundamental questions: How is the mechanical state of the cell regulated by local protein expression and global pattering? In what way does stress feedback onto the larger developmental program? In this dissertation, we begin to approach these questions through the introduction and analysis of a multi-scale model of epithelial mechanics which explicitly connects cytoskeletal protein activity to tissue-level stress. In Chapter 2, we introduce the discrete Active Tension Network (ATN) model of cellular mechanics. ATNs are tissues that satisfy two primary assumptions: that the mechanical balance of cells is dominated by cortical tension and that myosin actively remodels the actin cytoskeleton in a stress-dependent manner. Remarkably, the interplay of these features allows for angle-preserving, i.e. 'isogonal', dilations or contractions of local cell geometry that do not generate stress. Asymptotically this model is stabilized provided there is mechanical feedback on expression of myosin within the cell; we take this to be a strong prediction to be tested. The ATN model exposes a fundamental connection between equilibrium cell geometry and its underlying force network. In Chapter 3, we relax the tension-net approximation and demonstrate that at equilibrium, epithelial tissues with non-uniform pressure have non-trivial geometric constraints that imply the network is described by a weighted `dual' triangulation. We show that the dual triangulation encodes all information about the mechanical state of an epithelial tissue. Utilizing the stress-geometry 'duality', we formulate a local "Mechanical Inference" of cellular-level stress using solely cell geometry that dramatically improves over past image-based inference techniques. In Chapter 4, we generalize the ATN model to explore the controlled re-arrangement of cells within epithelial tissues. This requires us to explicitly consider the effects of cadherin mediated adhesion, and its regulation, on tissue morphogenesis. We find that positive feedback between myosin and cortical tension, along with traction-dependent depletion of cytoskeletal cadherin is sufficient to recapitulate the morphogenetic movement of cells observed during convergent extension of the lateral ectoderm during Drosophila embryogenesis. Statistical analyses of live-imaging data supports the fundamentals of the model. Chapter 5 focuses on morphogenesis at a mesoscopic scale by coarse-graining the cellular ATN model. Under this limit, we expect an epithelial tissue should behave as an effective viscous, compressible fluid driven by myosin gradients on intermediate time-scales. Theoretical predictions are empirically tested against in-toto microscopy data obtained during early Drosophila embryogenesis.

THE PENETRATION OF REOVIRUS RNA AND INITIATION OF ITS GENETIC FUNCTION IN L-STRAIN FIBROBLASTS

PubMed Central

Silverstein, Samuel C.; Dales, Samuel

1968-01-01

Reovirus type 3 is phagocytized by L cells and rapidly sequestered inside lysosomes. Hydrolases within these organelles are capable of stripping the viral coat proteins, but they fail to degrade the double-stranded RNA genome. These observations support the view that sojourn of reovirus in lysosomes, when the lytic enzymes uncoat its genome, is an obligatory step in the sequence of infection. Although the mechanism for transferring the uncoated RNA out of lysosomes remains to be elucidated, evidence is presented suggesting that progeny genomes are bound to site(s) possessing the fine structure of viral inclusions or factories. It appears that both the synthesis of single- and double-stranded viral RNA and the morphogenesis of progeny virus particles occur in such factories. PMID:19806702

Multicellular Models of Morphogenesis

EPA Science Inventory

EPA’s Virtual Embryo project (v-Embryo™), in collaboration with developers of CompuCell3D, aims to create computer models of morphogenesis that can be used to address the effects of chemical perturbation on embryo development at the cellular level. Such computational (in silico) ...