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Sample records for developing tooth germ

  1. Morphometric approach to pulp fibroblast development in tooth germ.

    PubMed

    Căruntu, Irina-Draga; Săvinescu, Sergiu Daniel; Amălinei, Cornelia

    2014-01-01

    This paper builds a morphometric framework for the analysis of dental pulp fibroblast evolution during tooth development. We investigated 15 tooth germs (cases) organized, by histological criteria, in three groups corresponding to cap, early bell, and late bell stages, respectively. Each group comprised five cases. The morphometric description used the following parameters: area (A), perimeter (P)--automatically extracted by a color segmentation technique, and form factor (FF)--calculated as 4πA/P (2). The designed framework operated at inter- and intragroup levels. The intergroup analysis quantified the differences between groups, in the sense of a relative distance (RD) adequately defined by mean-value scaling. We showed that the stage of early bell is approximately 5 times closer to late bell than to cap. The quantification procedure required concomitant information about A, P parameters (as P versus A dependences, or FF values), whereas the procedure failed for A or P separately used. The intragroup analysis quantified the similarity of the cases belonging to the same stage. We proved that, unlike the intergroup tests, the individual exploitation of all three descriptors A, P, and FF is effective, yielding highly compatible results. Within any group, most cases presented RDs less than 10% from the group mean value, regardless of the descriptor type. PMID:25057501

  2. Multiple functional involvement of thymosin beta-4 in tooth germ development.

    PubMed

    Ookuma, Yukiko F; Kiyoshima, Tamotsu; Kobayashi, Ieyoshi; Nagata, Kengo; Wada, Hiroko; Fujiwara, Hiroaki; Yamaza, Haruyoshi; Nonaka, Kazuaki; Sakai, Hidetaka

    2013-02-01

    Thymosin beta-4 (Tβ4) is known to be ubiquitously involved in the actin monomer sequestering on the cytoskeleton. Our previous study showed specific temporal and special in situ expression pattern of Tβ4 mRNA in dental epithelial and mesenchymal cells in the developing tooth germ of the mouse lower first molar. In this study, we examined the functional implications of Tβ4 in the developmental course of the mouse lower first molar. An inhibition assay using Tβ4 antisense sulfur-substituted oligodeoxynucleotide (AS S-ODN) in cultured embryonic day 11.0 (E11.0) mandibles showed a significant growth inhibition of the tooth germ. However, no growth arrest of the cultured E15.0 tooth germ was observed by using Tβ4 AS S-ODN. The Tβ4 knockdown led to significantly decreased expression levels of type II/III runt-related transcription factor 2 (Runx2) and nucleolin (Ncl) in the cultured E11.0 mandibles. Since our previous studies proved that the inhibition of type II/III Runx2 and Ncl translations resulted in the developmental arrest of the tooth germ in the cultured E11.0 mandible, Tβ4 appears to play roles in tooth germ development via the regulation of the type II/III Runx2 and Ncl expressions. Tβ4 knockdown also resulted in decreased secretion of matrix metalloproteinase (Mmp)-2, a reduced cell motility activity and upregulation of E-cadherin in dental epithelial mDE6 cells. These results suggest that Tβ4 plays multiple functional roles in odontogenic epithelial cells in the early stages of tooth germ development by regulating the expression of odontogenesis-related genes. PMID:23052839

  3. The Slice Culture Method for Following Development of Tooth Germs In Explant Culture

    PubMed Central

    Alfaqeeh, Sarah A.; Tucker, Abigail S.

    2013-01-01

    Explant culture allows manipulation of developing organs at specific time points and is therefore an important method for the developmental biologist. For many organs it is difficult to access developing tissue to allow monitoring during ex vivo culture. The slice culture method allows access to tissue so that morphogenetic movements can be followed and specific cell populations can be targeted for manipulation or lineage tracing. In this paper we describe a method of slice culture that has been very successful for culture of tooth germs in a range of species. The method provides excellent access to the tooth germs, which develop at a similar rate to that observed in vivo, surrounded by the other jaw tissues. This allows tissue interactions between the tooth and surrounding tissue to be monitored. Although this paper concentrates on tooth germs, the same protocol can be applied to follow development of a number of other organs, such as salivary glands, Meckel's cartilage, nasal glands, tongue, and ear. PMID:24300332

  4. 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

  5. Development of rotation of mandibular premolar tooth germs in the dog.

    PubMed

    Esaka, S

    1982-01-01

    The development of premolar tooth germs in dogs, particularly their rotation and crowding, was examined on radiographs, dissected specimens of tooth germs, serial sections stained by Masson-Goldner's technique and reconstructed models. The materials used were the mandibles of 32 puppies from birth to 6 months, and the species was a highly pedigreed Shiba Inu which has no crowding of the premolars in the mature stage. The results obtained are as follows. (1) Rotations and crowdings of premolars, similar to those in brachygnathus dogs and wolves raised in captivity, were observed during ontogenesis of dolichocephalic dogs, whose adult state exhibits no crowding of teeth. (2) The type of rotation was B (the mesial portion is rotated buccally) for the second and third premolars and L (the mesial portion lingually) for the fourth premolar. (3) The rotations of the premolars did not coincide with those of their deciduous predecessors. (4) These rotations appeared in the bud and cap stages of premolars, before the formation of roots of deciduous molars. The premolars developed crowding at 5 months when they increased in dimension. PMID:7158282

  6. Quantitative analysis of fluoride-induced hypermineralization of developing enamel in neonatal hamster tooth germs

    NASA Astrophysics Data System (ADS)

    Tros, G. H. J.; Lyaruu, D. M.; Vis, R. D.

    1993-10-01

    A procedure was developed for analysing the effect of fluoride on mineralization in the enamel of neonatal hamster molars during amelogenesis by means of the quantitative determination of the mineral content. In this procedure the distribution of calcium and mineral concentration was determined in sections containing developing tooth enamel mineral embedded in an organic epoxy resin matrix by means of the micro-PIXE technique. This allowed the determination of the calcium content along preselected tracks with a spatial resolution of 2 μm using a microprobe PIXE setup with a 3 MeV proton beam of 10 to 50 pA with a spot size of 2 μm in the track direction. In this procedure the X-ray yield is used as a measure for the calcium content. The thickness of each sample section is determined independently by measuring the energy loss of α-particles from a calibration source upon passing through the sample. The sample is considered as consisting of two bulk materials, allowing the correction for X-ray self-absorption and the calculation of the calcium concentration. The procedure was applied for measuring the distribution of mineral concentration in 2 μm thick sections taken from tooth germs of hamsters administered with NaF. The measurements indicated that a single intraperitoneal administration of 20 mg NaF/kg body weight to 4-to-5-day-old hamsters leads within 24 h to hypermineralization of certain focal enamel surface areas containing cystic lesions under transitional and early secretory ameloblasts. The mineral concentration there is substantially increased due to the fluoride treatment (35%, instead of 5 to 10% as in the controls), indicating that the normal mineralization process has been seriously disturbed. Furthermore it is found that using this technique the mineral concentration peaks at about 70% at the dentine-enamel junction, which is comparable to that reported for human dentine using other techniques.

  7. The effect of fluoride on mineralization during tooth germ development in neonatal hamsters

    NASA Astrophysics Data System (ADS)

    Tros, G. H. J.; Lyaruu, D. M.; Vis, R. D.

    1990-04-01

    The effect of fluoride on calcium and phosphorus content (a measure for mineralization) in maxillary first molar tooth germs from neonatal hamsters (4 to 5 days old, 4 to 5 g body weight) was analysed using the proton nuclear microprobe PIXE setup of the Vrije Universiteit. A 3 MeV proton beam of about 500 pA with a spot size of 5 × 20 μm 2 was used to perform scans of about 400 μm, each taking about 20 to 30 minutes. The smaller beam dimension was always tuned parallel to the scan direction. Line scans with a lateral resolution of 5 μm were made across the enamel organ of germs from animals injected with 20 mg NaF/kg body weight 24 h prior to dissection. The control animals were injected with NaCl. Fluoride administration induced the formation of sub-ameloblastic cystic lesions under some (but not all) populations of transitional and secretory ameloblasts, accompanied by hypermineralization (deposition of more mineral than that found in the controls) of the underlying enamel surface. These hypermineralized regions had been shown in earlier studies to contain elevated fluorine content [1,2].

  8. MicroRNAome and Expression Profile of Developing Tooth Germ in Miniature Pigs

    PubMed Central

    Li, Ang; Song, Tieli; Wang, Fu; Liu, Dayong; Fan, Zhipeng; Zhang, Chunmei; He, Junqi; Wang, Songlin

    2012-01-01

    MicroRNAs (miRNAs) play important roles in the regulation of rodent tooth development, but little is known about their role in tooth development in large mammals. We identified 637 unique miRNA sequences in a large-scale screen for miRNA expression profiles in the developing lower deciduous molars of miniature pigs (Sus scrofa) using Illumina Solexa deep sequencing. These candidate miRNAs and another 105 known Sus scrofa miRNAs were included in the custom-designed microarray and used to analyze the miRNA expression profile in the bud, cap, early bell, and late bell stages of tooth development. Microarray analysis revealed 166 transcripts that were differentially expressed in the four stages. Bioinformatic analysis identified 18 key miRNAs, including let-7f, miR-128, miR-200b, and miR-200c, that might play key roles in tooth development. Taken together, our results not only identified the specific microRNAome and expression profile in developing lower deciduous molars of the miniature pig, but they also provided useful information for investigating the molecular mechanism of tooth development in the miniature pig. PMID:23272230

  9. Facioscapulohumeral muscular dystrophy (FSHD) region gene 1 (FRG1) expression and possible function in mouse tooth germ development.

    PubMed

    Hasegawa, Kana; Wada, Hiroko; Nagata, Kengo; Fujiwara, Hiroaki; Wada, Naohisa; Someya, Hirotaka; Mikami, Yurie; Sakai, Hidetaka; Kiyoshima, Tamotsu

    2016-08-01

    Abnormal expression of Facioscapulohumeral muscular dystrophy (FSHD) region gene 1 (FRG1) is involved in the pathogenesis of FSHD. FRG1 is also important for the normal muscular and vascular development. Our previous study showed that FRG1 is one of the highly expressed genes in the mandible on embryonic day 10.5 (E10.5) than on E12.0. In this study, we investigated the temporospatial expression pattern of FRG1 mRNA and protein during the development of the mouse lower first molar, and also evaluated the subcellular localization of the FRG1 protein in mouse dental epithelial (mDE6) cells. The FRG1 expression was identified in the dental epithelial and mesenchymal cells at the initiation and bud stages. It was detected in the inner enamel epithelium at the cap and early bell stages. At the late bell and root formation stages, these signals were detected in ameloblasts and odontoblasts during the formation of enamel and dentin matrices, respectively. The FRG1 protein was localized in the cytoplasm in the mouse tooth germ in vivo, while FRG1 was detected predominantly in the nucleus and faintly in the cytoplasm in mDE6 cells in vitro. In mDE6 cells treated with bone morphogenetic protein 4 (BMP4), the protein expression of FRG1 increased in cytoplasm, suggesting that FRG1 may translocate to the cytoplasm. These findings suggest that FRG1 is involved in the morphogenesis of the tooth germ, as well as in the formation of enamel and dentin matrices and that FRG1 may play a role in the odontogenesis in the mouse following BMP4 stimulation. PMID:27234941

  10. TLR signalling can modify the mineralization of tooth germ.

    PubMed

    Papp, Tamas; Hollo, Krisztina; Meszar-Katona, Eva; Nagy, Zoltan; Polyak, Angela; Miko, Edit; Bai, Peter; Felszeghy, Szabolcs

    2016-05-01

    Objective The aim of this work is to investigate the possible role of Toll-like receptor 4 (TLR4) during the development of mouse tooth germ. TLR4 is well known to inhibit mineralization and cause inflammation in mature odontoblasts and dental pulp cells. However, unlike these pathological functions of TLR4, little is known about the developmental function(s) of TLR4 during tooth development. Materials and methods TLR4 expression was studied via Western blot in developing lower mouse incisors from E13.5 to E18.5. To generate functional data about the effects of TLR4, a specific agonist (LPS) was applied to the medium of in vitro tooth germ cultures, followed by Western blot, histochemical staining, ELISA assay, in situ hybridization and RT-qPCR. Results Increased accumulation of biotin-labelled LPS was detected in the enamel organ and in preodontoblasts. LPS treatment induced degradation of the inhibitor molecule (IκB) of the NF-κB signalling pathway. However, no morphological alterations were detected in cultured tissue after LPS addition at the applied dosage. Activation of TLR4 inhibited the mineralization of enamel and dentin, as demonstrated by alizarin red staining and as decreased levels of collagen type X. mRNA expression of ameloblastin was elevated after LPS administration. Conclusion These results demonstrate that TLR4 may decrease the mineralization of hard tissues of the tooth germ and may trigger the maturation of ameloblasts; it can give valuable information to understand better congenital tooth abnormalities. PMID:26763602

  11. X-ray micro-analysis of the mineralization patterns in developing enamel in hamster tooth germs exposed to fluoride in vitro during the secretory phase of amelogenesis

    SciTech Connect

    Lyaruu, D.M.; Blijleven, N.; Hoeben-Schornagel, K.; Bronckers, A.L.; Woeltgens, J.H.

    1989-09-01

    The developing enamel from three-day-old hamster first maxillary (M1) molar tooth germs exposed to fluoride (F-) in vitro was analyzed for its mineral content by means of the energy-dispersive x-ray microanalysis technique. The aim of this study was to obtain semi-quantitative data on the F(-)-induced hypermineralization patterns in the enamel and to confirm that the increase in electron density observed in micrographs of F(-)-treated enamel is indeed due to an increase in mineral content in the fluorotic enamel. The tooth germs were explanted during the early stages of secretory amelogenesis and initially cultured for 24 hr in the presence of 10 ppm F- in the culture medium. The germs were then cultured for another 24 hr without F-. In order to compare the ultrastructural results directly with the microprobe data, we used the same specimens for both investigations. The net calcium counts (measurement minus background counts) in the analyses were used as a measure of the mineral content in the enamel. The aprismatic pre-exposure enamel, deposited in vivo before the onset of culture, was the most hypermineralized region in the fluorotic enamel, i.e., it contained the highest amount of calcium measured. The degree of the F(-)-induced hypermineralization gradually decreased (but was not abolished) in the more mature regions of the enamel. The unmineralized enamel matrix secreted during the initial F- treatment in vitro mineralized during the subsequent culture without F-. The calcium content in this enamel layer was in the same order of magnitude as that recorded for the newly deposited enamel in control tooth germs cultured without F-.

  12. Tooth Germ-Like Construct Transplantation for Whole-Tooth Regeneration: An In Vivo Study in the Miniature Pig.

    PubMed

    Yang, Kai-Chiang; Kitamura, Yutaka; Wu, Chang-Chin; Chang, Hao-Hueng; Ling, Thai-Yen; Kuo, Tzong-Fu

    2016-04-01

    The purpose of this study was to demonstrate the feasibility of whole-tooth regeneration using a tooth germ-like construct. Dental pulp from upper incisors, canines, premolars, and molars were extracted from sexually mature miniature pigs. Pulp tissues were cultured and expanded in vitro to obtain dental pulp stem cells (DPSCs), and cells were differentiated into odontoblasts and osteoblasts. Epithelial cells were isolated from gingival epithelium. The epithelial cells, odontoblasts, and osteoblasts were seeded onto the surface, upper, and lower layers, respectively, of a bioactive scaffold. The lower first and second molar tooth germs were removed bilaterally and the layered cell/scaffold constructs were transplanted to the mandibular alveolar socket of a pig. At 13.5 months postimplantation, seven of eight pigs developed two teeth with crown, root, and pulp structures. Enamel-like tissues, dentin, cementum, odontoblasts, and periodontal tissues were found upon histological inspection. The regenerated tooth expressed dentin matrix protein-1 and osteopontin. All pigs had regenerated molar teeth regardless of the original tooth used to procure the DPSCs. Pigs that had tooth germs removed or who received empty scaffolds did not develop teeth. Although periodontal ligaments were generated, ankylosis was found in some animals. This study revealed that implantation of a tooth germ-like structure generated a complete tooth with a high success rate. The implant location may influence the morphology of the regenerated tooth. PMID:26582651

  13. Fetal age estimation using MSCT scans of deciduous tooth germs.

    PubMed

    Minier, Marie; Maret, Delphine; Dedouit, Fabrice; Vergnault, Marion; Mokrane, Fathima-Zohra; Rousseau, Hervé; Adalian, Pascal; Telmon, Norbert; Rougé, Daniel

    2014-01-01

    Evaluation of fetal age is an essential element in many fields such as anthropology, odontology, paleopathology, and forensic sciences. This study examines the correlation between fetal age, femoral diaphyseal length (considered as the gold standard), and deciduous tooth germs of fetuses aged 22 to 40 weeks amenorrhea (WA) based on computed tomography (MSCT) reconstructions. Qualitative and quantitative studies of femoral and deciduous tooth germ lengths were performed on 81 fetuses (39 females and 42 males). R software was used for statistical analyses. Intra-observer and inter-observer variabilities and the interclass correlation coefficient (ICC) were calculated. Correlation coefficients (R (2)) and linear regression equations were calculated. Intra- and inter-observer variabilities were very satisfactory (intra-observer ICC ≥ 0.96, inter-observer ICC ≥ 0.95). Femoral length was significantly correlated with age (R (2) = 0.9). The correlation coefficient between age and height, width, and dental volume was R (2) ≥ 0.73. Tooth germs were good indicators of fetal age. Our method appears to be reliable and reproducible, and the results of this study agreed with those of the literature. The dental formula provided a precise estimation of fetal age between 25 and 32 WA. Tooth germs were reliable indicators of fetal age, and multislice computed tomography was shown to be an innovative and reliable technology for this purpose. PMID:23828625

  14. Appearance pattern of tooth germs with developmental process in Mylopharyngodon piceus

    NASA Astrophysics Data System (ADS)

    Yue, Pei-Qi; Nakajima, Tsuneo

    1995-06-01

    The pharyngeal dental formula of Mylopharyngodon piceus is 4 5 as a rule, and the dentition is asymmetrical. It is difficult to identify each tooth in the larval dentition. In this paper the appearance pattern of tooth germ with development process in this fish is described in detail. The formation pattern of the left dentition is contrasted with that of the right one. In the developmental process, the left pharyngeal dentition lacks teeth at position An3. Thus the left dentition is D-type as designated by Nakajima (1984), while the right one is A-type.

  15. PKA regulatory subunit expression in tooth development.

    PubMed

    de Sousa, Sílvia Ferreira; Kawasaki, Katsushige; Kawasaki, Maiko; Volponi, Ana Angelova; Gomez, Ricardo Santiago; Gomes, Carolina Cavaliéri; Sharpe, Paul T; Ohazama, Atsushi

    2014-05-01

    Protein kinase A (PKA) plays critical roles in many biological processes including cell proliferation, cell differentiation, cellular metabolism and gene regulation. Mutation in PKA regulatory subunit, PRKAR1A has previously been identified in odontogenic myxomas, but it is unclear whether PKA is involved in tooth development. The aim of the present study was to assess the expression of alpha isoforms of PKA regulatory subunit (Prkar1a and Prkar2a) in mouse and human odontogenesis by in situ hybridization. PRKAR1A and PRKAR2A mRNA transcription was further confirmed in a human deciduous germ by qRT-PCR. Mouse Prkar1a and human PRKAR2A exhibited a dynamic spatio-temporal expression in tooth development, whereas neither human PRKAR1A nor mouse Prkar2a showed their expression in odontogenesis. These isoforms thus showed different expression pattern between human and mouse tooth germs. PMID:24755349

  16. On the analysis of neonatal hamster tooth germs with the photon microprobe at Daresbury, UK

    NASA Astrophysics Data System (ADS)

    Tros, G. H. J.; Van Langevelde, F.; Vis, R. D.

    1990-04-01

    Complementary to the micro-PIXE experiments performed on hamster tooth germs to elucidate the role of fluoride during the growth, the photon microprobe at Daresbury was used to obtain information on the distribution of Zn. The germs of fluoride-administered hamsters, together with a control group, were analyzed with the micro-synchrotron radiation fluorescence method (micro-SXRF).

  17. Developmental changes in primary cilia in the mouse tooth germ and oral cavity.

    PubMed

    Hisamoto, Meri; Goto, Marie; Muto, Mami; Nio-Kobayashi, Junko; Iwanaga, Toshihiko; Yokoyama, Atsuro

    2016-01-01

    The primary cilium, a sensory apparatus, functions as both a chemical and mechanical sensor to receive environmental stimuli. The present study focused on the primary cilia in the epithelialmesenchymal interaction during tooth development. We examined the localization and direction of projection of primary cilia in the tooth germ and oral cavity of mice by immunohistochemical observation. Adenylyl cyclase 3 (ACIII)-immunolabeled cilia were visible in the inner/outer enamel epithelium of molars at the fetal stage and then conspicuously developed in the odontoblast layer postnatally. The primary cilia in ameloblasts and odontoblasts-shown by the double staining of acetylated tubulin and γ-tubulin-were regularly arranged from postnatal Day12, projecting apart from each other. The periodontal ligament possessed ACIII-positive cilia, which gathered on both sides of the dentin/cement and alveolar bone in postnatal days. In the oral cavity, numerous long primary cilia immunoreactive for ACIII were condensed at subepithelial stromal cells in the oral processes in fetuses, while postnatally a small number of short cilia were dispersed throughout the stroma of the oral cavity. These findings suggest that the primary cilia showing stage- and regionspecific morphology are involved in the epithelial-mesenchymal interaction during tooth development via mechano- and/or chemoreception for growth factors. PMID:27356608

  18. Interactions of the tooth and bone during development.

    PubMed

    Alfaqeeh, S A; Gaete, M; Tucker, A S

    2013-12-01

    The tooth works as a functional unit with its surrounding bony socket, the alveolar bone. The growth of the tooth and alveolar bone is co-ordinated so that a studied distance always separates the 2, known as the tooth-bone interface (TBI). Lack of mineralization, a crucial feature of the TBI, creates the space for the developing tooth to grow and the soft tissues of the periodontium to develop. We have investigated the interactions between the tooth and its surrounding bone during development, focusing on the impact of the developing alveolar bone on the development of the mouse first molar (M1). During development, TRAP-positive osteoclasts are found to line the TBI as bone starts to be deposited around the tooth, removing the bone as the tooth expands. An enhancement of osteoclastogenesis through RANK-RANKL signaling results in an expansion of the TBI, showing that osteoclasts are essential for defining the size of this region. Isolation of the M1 from the surrounding mesenchyme and alveolar bone leads to an expansion of the tooth germ, driven by increased proliferation, indicating that, during normal development, the growth of the tooth germ is constrained by the surrounding tissues. PMID:24155263

  19. Dpysl4 Is Involved in Tooth Germ Morphogenesis through Growth Regulation, Polarization and Differentiation of Dental Epithelial Cells

    PubMed Central

    Yasukawa, Masato; Ishida, Kentaro; Yuge, Yohei; Hanaoka, Mai; Minami, Yoko; Ogawa, Miho; Sasaki, Takashi; Saito, Masahiro; Tsuji, Takashi

    2013-01-01

    Dihydropyrimidinase-related protein 4 (Dpysl4) is a known regulator of hippocampal neuron development. Here, we report that Dpysl4 is involved in growth regulation, polarization and differentiation of dental epithelial cells during tooth germ morphogenesis. A reduction in Dpysl4 gene expression in the tooth germ produced a loss of ameloblasts, resulting in the decrease of synthesis and secretion of enamel. The inhibition of Dpysl4 gene expression led to promotion of cell proliferation of inner enamel epithelial cells and inhibition of the differentiation of these cells into pre-ameloblasts, which was confirmed by analyzing cell polarization, columnar cell structure formation and the expression of ameloblast marker genes. By contrast, overexpression of Dpysl4 in dental epithelial cells induces inhibition of growth and increases the expression of the inner enamel epithelial cell marker gene, Msx2. These findings suggest that Dpysl4 plays essential roles in tooth germ morphogenesis through the regulation of dental epithelial cell proliferation, cell polarization and differentiation. PMID:23630450

  20. Modification of tooth development by heat shock protein 60.

    PubMed

    Papp, Tamas; Polyak, Angela; Papp, Krisztina; Meszar, Zoltan; Zakany, Roza; Meszar-Katona, Eva; Tünde, Palne Terdik; Ham, Chang Hwa; Felszeghy, Szabolcs

    2016-01-01

    Although several heat shock proteins have been investigated in relation to tooth development, no available information is available about the spatial and temporal expression pattern of heat shock protein 60 (Hsp 60). To characterize Hsp 60 expression in the structures of the developing tooth germ, we used Western blotting, immunohistochemistry and in situ hybridization. Hsp 60 was present in high amounts in the inner and outer enamel epithelia, enamel knot (EK) and stratum intermedium (SI). Hsp 60 also appeared in odontoblasts beginning in the bell stage. To obtain data on the possible effect of Hsp 60 on isolated lower incisors from mice, we performed in vitro culturing. To investigate the effect of exogenous Hsp 60 on the cell cycle during culturing, we used the 5-bromo-2-deoxyuridine (BrdU) incorporation test on dental cells. Exogenously administered Hsp 60 caused bluntness at the apical part of the 16.5-day-old tooth germs, but it did not influence the proliferation rate of dental cells. We identified the expression of Hsp 60 in the developing tooth germ, which was present in high concentrations in the inner and outer enamel epithelia, EK, SI and odontoblasts. High concentration of exogenous Hsp 60 can cause abnormal morphology of the tooth germ, but it did not influence the proliferation rate of the dental cells. Our results suggest that increased levels of Hsp 60 may cause abnormalities in the morphological development of the tooth germ and support the data on the significance of Hsp during the developmental processes. PMID:27025262

  1. Modification of tooth development by heat shock protein 60

    PubMed Central

    Papp, Tamas; Polyak, Angela; Papp, Krisztina; Meszar, Zoltan; Zakany, Roza; Meszar-Katona, Eva; Tünde, Palne Terdik; Ham, Chang Hwa; Felszeghy, Szabolcs

    2016-01-01

    Although several heat shock proteins have been investigated in relation to tooth development, no available information is available about the spatial and temporal expression pattern of heat shock protein 60 (Hsp 60). To characterize Hsp 60 expression in the structures of the developing tooth germ, we used Western blotting, immunohistochemistry and in situ hybridization. Hsp 60 was present in high amounts in the inner and outer enamel epithelia, enamel knot (EK) and stratum intermedium (SI). Hsp 60 also appeared in odontoblasts beginning in the bell stage. To obtain data on the possible effect of Hsp 60 on isolated lower incisors from mice, we performed in vitro culturing. To investigate the effect of exogenous Hsp 60 on the cell cycle during culturing, we used the 5-bromo-2-deoxyuridine (BrdU) incorporation test on dental cells. Exogenously administered Hsp 60 caused bluntness at the apical part of the 16.5-day-old tooth germs, but it did not influence the proliferation rate of dental cells. We identified the expression of Hsp 60 in the developing tooth germ, which was present in high concentrations in the inner and outer enamel epithelia, EK, SI and odontoblasts. High concentration of exogenous Hsp 60 can cause abnormal morphology of the tooth germ, but it did not influence the proliferation rate of the dental cells. Our results suggest that increased levels of Hsp 60 may cause abnormalities in the morphological development of the tooth germ and support the data on the significance of Hsp during the developmental processes. PMID:27025262

  2. ClC-7 Deficiency Impairs Tooth Development and Eruption

    PubMed Central

    Wang, He; Pan, Meng; Ni, Jinwen; Zhang, Yanli; Zhang, Yutao; Gao, Shan; Liu, Jin; Wang, Zhe; Zhang, Rong; He, Huiming; Wu, Buling; Duan, Xiaohong

    2016-01-01

    CLCN7 gene encodes the voltage gated chloride channel 7 (ClC-7) in humans. The mutations in CLCN7 have been associated with osteopetrosis in connection to the abnormal osteoclasts functions. Previously, we found that some osteopetrosis patients with CLCN7 mutations suffered from impacted teeth and root dysplasia. Here we set up two in vivo models under a normal or an osteoclast-poor environment to investigate how ClC-7 affects tooth development and tooth eruption. Firstly, chitosan-Clcn7-siRNA nanoparticles were injected around the first maxillary molar germ of newborn mice and caused the delay of tooth eruption and deformed tooth with root dysplasia. Secondly, E13.5 molar germs infected with Clcn7 shRNA lentivirus were transplanted under the kidney capsule and presented the abnormal changes in dentin structure, periodontal tissue and cementum. All these teeth changes have been reported in the patients with CLCN7 mutation. In vitro studies of ameloblasts, odontoblasts and dental follicle cells (DFCs) were conducted to explore the involved mechanism. We found that Clcn7 deficiency affect the differentiation of these cells, as well as the interaction between DFCs and osteoclasts through RANKL/OPG pathway. We conclude that ClC-7 may affect tooth development by directly targeting tooth cells, and regulate tooth eruption through DFC mediated osteoclast pathway. PMID:26829236

  3. ClC-7 Deficiency Impairs Tooth Development and Eruption.

    PubMed

    Wang, He; Pan, Meng; Ni, Jinwen; Zhang, Yanli; Zhang, Yutao; Gao, Shan; Liu, Jin; Wang, Zhe; Zhang, Rong; He, Huiming; Wu, Buling; Duan, Xiaohong

    2016-01-01

    CLCN7 gene encodes the voltage gated chloride channel 7 (ClC-7) in humans. The mutations in CLCN7 have been associated with osteopetrosis in connection to the abnormal osteoclasts functions. Previously, we found that some osteopetrosis patients with CLCN7 mutations suffered from impacted teeth and root dysplasia. Here we set up two in vivo models under a normal or an osteoclast-poor environment to investigate how ClC-7 affects tooth development and tooth eruption. Firstly, chitosan-Clcn7-siRNA nanoparticles were injected around the first maxillary molar germ of newborn mice and caused the delay of tooth eruption and deformed tooth with root dysplasia. Secondly, E13.5 molar germs infected with Clcn7 shRNA lentivirus were transplanted under the kidney capsule and presented the abnormal changes in dentin structure, periodontal tissue and cementum. All these teeth changes have been reported in the patients with CLCN7 mutation. In vitro studies of ameloblasts, odontoblasts and dental follicle cells (DFCs) were conducted to explore the involved mechanism. We found that Clcn7 deficiency affect the differentiation of these cells, as well as the interaction between DFCs and osteoclasts through RANKL/OPG pathway. We conclude that ClC-7 may affect tooth development by directly targeting tooth cells, and regulate tooth eruption through DFC mediated osteoclast pathway. PMID:26829236

  4. Transcriptomic profiling comparison of YAP over-expression and conditional knockout mouse tooth germs

    PubMed Central

    Liu, Ming; Wang, Xiu-Ping

    2015-01-01

    To identify the downstream target genes of YAP, we used RNA-Seq technology to compare the transcriptomic profilings of Yap conditional knockout (Yap CKO) and YAP over-expression mouse tooth germs. Our results showed that some Hox, Wnt and Laminin family genes had concurrent changes with YAP transcripts, indicating that the expression of these genes may be regulated by YAP. Here, we provide the detailed experimental procedure for the transcriptomic profiling results (NCBI GEO accession number GSE65524). The associated study on the regulation of Hoxa1 and Hoxc13 genes by YAP was published in Molecular Cellular Biology in 2015 [Liu et al., 2015]. PMID:26484260

  5. Molecular Genetics of Tooth Development

    PubMed Central

    Bei, Marianna

    2009-01-01

    Organogenesis depends upon a well-ordered series of inductive events involving coordination of molecular pathways that regulate the generation and patterning of specific cell types. Key questions in organogenesis involve the identification of the molecular mechanisms by which proteins interact to organize distinct pattern formation and cell fate determination. Tooth development is an excellent context for investigating this complex problem because of the wealth of information emerging from studies of model organisms and human mutations. Since there are no obvious sources of stem cells in adult human teeth, any attempt to create teeth de novo will likely require the re-programming of other cell types. Thus, the fundamental understanding of the control mechanisms responsible for normal tooth patterning in the embryo will help us understand cell fate specificity and may provide valuable information towards tooth organ regeneration. PMID:19875280

  6. Current knowledge of tooth development: patterning and mineralization of the murine dentition

    PubMed Central

    Catón, Javier; Tucker, Abigail S

    2009-01-01

    The integument forms a number of different types of mineralized element, including dermal denticles, scutes, ganoid scales, elasmoid scales, fin rays and osteoderms found in certain fish, reptiles, amphibians and xenarthran mammals. To this list can be added teeth, which are far more widely represented and studied than any of the other mineralized elements mentioned above, and as such can be thought of as a model mineralized system. In recent years the focus for studies on tooth development has been the mouse, with a wealth of genetic information accrued and the availability of cutting edge techniques. It is the mouse dentition that this review will concentrate on. The development of the tooth will be followed, looking at what controls the shape of the tooth and how signals from the mesenchyme and epithelium interact to lead to formation of a molar or incisor. The number of teeth generated will then be investigated, looking at how tooth germ number can be reduced or increased by apoptosis, fusion of tooth germs, creation of new tooth germs, and the generation of additional teeth from existing tooth germs. The development of mineralized tissue will then be detailed, looking at how the asymmetrical deposition of enamel is controlled in the mouse incisor. The continued importance of epithelial–mesenchymal interactions at these later stages of tooth development will also be discussed. Tooth anomalies and human disorders have been well covered by recent reviews, therefore in this paper we wish to present a classical review of current knowledge of tooth development, fitting together data from a large number of recent research papers to draw general conclusions about tooth development. PMID:19422427

  7. Genomic Landscape of Developing Male Germ Cells

    PubMed Central

    Lee, Tin-Lap; Pang, Alan Lap-Yin; Rennert, Owen M.; Chan, Wai-Yee

    2010-01-01

    Spermatogenesis is a highly orchestrated developmental process by which spermatogonia develop into mature spermatozoa. This process involves many testis- or male germ cell-specific gene products whose expressions are strictly regulated. In the past decade the advent of high-throughput gene expression analytical techniques has made functional genomic studies of this process, particularly in model animals such as mice and rats, feasible and practical. These studies have just begun to reveal the complexity of the genomic landscape of the developing male germ cells. Over 50% of the mouse and rat genome are expressed during testicular development. Among transcripts present in germ cells, 40% – 60% are uncharacterized. A number of genes, and consequently their associated biological pathways, are differentially expressed at different stages of spermatogenesis. Developing male germ cells present a rich repertoire of genetic processes. Tissue-specific as well as spermatogenesis stage-specific alternative splicing of genes exemplifies the complexity of genome expression. In addition to this layer of control, discoveries of abundant presence of antisense transcripts, expressed psuedogenes, non-coding RNAs (ncRNA) including long ncRNAs, microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs), and retrogenes all point to the presence of multiple layers of expression and functional regulation in male germ cells. It is anticipated that application of systems biology approaches will further our understanding of the regulatory mechanism of spermatogenesis.† PMID:19306351

  8. Epithelial histogenesis during tooth development.

    PubMed

    Lesot, H; Brook, A H

    2009-12-01

    This paper reviews the current understanding of the progressive changes mediating dental epithelial histogenesis as a basis for future collaborative studies. Tooth development involves morphogenesis, epithelial histogenesis and cell differentiation. The consecutive morphological stages of lamina, bud, cap and bell are also characterized by changes in epithelial histogenesis. Differential cell proliferation rates, apoptosis, and alterations in adhesion and shape lead to the positioning of groups of cells with different functions. During tooth histo-morphogenesis changes occur in basement membrane composition, expression of signalling molecules and the localization of cell surface components. Cell positional identity may be related to cell history. Another important parameter is cell plasticity. Independently of signalling molecules, which play a major role in inducing or modulating specific steps, cell-cell and cell-matrix interactions regulate the plasticity/rigidity of particular domains of the enamel organ. This involves specifying in space the differential growth and influences the progressive tooth morphogenesis by shaping the epithelial-mesenchymal junction. Deposition of a mineralized matrix determines the final shape of the crown. All data reviewed in this paper were investigated in the mouse. PMID:18656852

  9. Expression of cytokeratin 8, vimentin, syndecan-1 and Ki-67 during human tooth development.

    PubMed

    Kero, D; Kalibovic Govorko, D; Vukojevic, K; Cubela, M; Soljic, V; Saraga-Babic, M

    2014-12-01

    Spatio-temporal immunolocalizations of cytokeratin 8 (CK8), vimentin, syndecan-1 and Ki-67 were analyzed in ten human incisors and canine tooth germs between the 7th and 20th developmental weeks. CK8 expression was mild to moderate in the epithelial tooth parts, while it shifted from absent or mild in its mesenchymal parts, but few cells, sparsely distributed throughout the tooth germ, strongly expressed CK8. As development progressed, CK8 expression increased to strong in preameloblasts, while expression of vimentin increased to moderate in the epithelial and mesenchymal tooth parts, particularly in the dental papilla and sac. Co-expression of CK8 and vimentin was observed in some parts of the tooth germ, and was increasing in the differentiating preameloblasts and preodontoblasts. Syndecan-1 showed characteristic shift of expression from epithelial to mesenchymal tooth parts, being particularly strong in dental papilla, sac and cervical loops, while co-expression of Ki-67/syndecan-1 was strong in the dental papilla. Our study demonstrated spatio-temporal expression and restricted co-expression of the investigated markers, indicating participation of CK8 and vimentin in cell proliferation and migration, and differentiation of preodontoblasts and preameloblasts. Our data also suggest involvement of syndecan-1 in morphogenesis of the developing tooth crown and cervical loops, and together with CK8 and vimentin in differentiation of preameloblasts and preodontoblasts. PMID:25120060

  10. Immunohistochemical Expression of GLUT-1 and HIF-1α in Tooth Germ, Ameloblastoma, and Ameloblastic Carcinoma.

    PubMed

    Sánchez-Romero, Celeste; Bologna-Molina, Ronell; Mosqueda-Taylor, Adalberto; Paes de Almeida, Oslei

    2016-08-01

    Hypoxia-inducible factor-1α (HIF-1α) promotes proteins that enable cell survival during hypoxia, such as glucose transporter 1 (GLUT-1). Their coexpression has been associated with aggressiveness in malignancies and has not been studied in odontogenic tumors. Immunohistochemical expression of HIF-1α and GLUT-1 was analyzed in 13 tooth germs (TGs), 55 ameloblastomas (AMs), and 3 ameloblastic carcinomas (ACs). HIF-1α was negative in all TGs, and just 1 case of AM and 1 of AC had nuclear positivity. GLUT-1 expressed in ameloblastic cells of all TGs, AMs, and ACs, with an increasing intensity, respectively, and was significantly higher in solid AM than in unicystic AM (P = .041). Absence of nuclear HIF-1α in TGs and most AMs suggest that GLUT-1 may be induced by alternative pathways to hypoxia. However, in ACs, HIF-1α may be activated; however, to confirm this, additional cases are needed. GLUT-1 overexpression could be related to aggressiveness in AMs and ACs and must represent a normal metabolite in TGs. PMID:27020375

  11. Two-step oligoclonal development of male germ cells.

    PubMed

    Ueno, Hiroo; Turnbull, Brit B; Weissman, Irving L

    2009-01-01

    During mouse development, primordial germ cells (PGCs) that give rise to the entire germ line are first identified within the proximal epiblast. However, long-term tracing of the fate of the cells has not been done wherein all cells in and around the germ-cell lineage are identified. Also, quantitative estimates of the number of founder PGCs using different models have come up with various numbers. Here, we use tetrachimeric mice to show that the progenitor numbers for the entire germ line in adult testis, and for the initiating embryonic PGCs, are both 4 cells. Although they proliferate to form polyclonal germ-cell populations in fetal and neonatal testes, germ cells that actually contribute to adult spermatogenesis originate from a small number of secondary founder cells that originate in the fetal period. The rest of the "deciduous" germ cells are lost, most likely by apoptosis, before the reproductive period. The second "actual" founder germ cells generally form small numbers of large monoclonal areas in testes by the reproductive period. Our results also demonstrate that there is no contribution of somatic cells to the male germ cell pool during development or in adulthood. These results suggest a model of 2-step oligoclonal development of male germ cells in mice, the second step distinguishing the heritable germ line from cells selected not to participate in forming the next generation. PMID:19098099

  12. Molecular regulatory mechanism of tooth root development

    PubMed Central

    Huang, Xiao-Feng; Chai, Yang

    2012-01-01

    The root is crucial for the physiological function of the tooth, and a healthy root allows an artificial crown to function as required clinically. Tooth crown development has been studied intensively during the last few decades, but root development remains not well understood. Here we review the root development processes, including cell fate determination, induction of odontoblast and cementoblast differentiation, interaction of root epithelium and mesenchyme, and other molecular mechanisms. This review summarizes our current understanding of the signaling cascades and mechanisms involved in root development. It also sets the stage for de novo tooth regeneration. PMID:23222990

  13. Elucidating human male germ cell development by studying germ cell cancer.

    PubMed

    Nettersheim, Daniel; Jostes, Sina; Schneider, Simon; Schorle, Hubert

    2016-10-01

    Human germ cell development is regulated in a spatio-temporal manner by complex regulatory networks. Here, we summarize results obtained in germ cell tumors and respective cell lines and try to pinpoint similarities to normal germ cell development. This comparison allows speculating about the critical and error-prone mechanisms, which when disturbed, lead to the development of germ cell tumors. Short after specification, primordial germ cells express markers of pluripotency, which, in humans, persists up to the stage of fetal/infantile spermatogonia. Aside from the rare spermatocytic tumors, virtually all seminomas and embryonal carcinomas express markers of pluripotency and show signs of pluripotency or totipotency. Therefore, it appears that proper handling of the pluripotency program appears to be the most critical step in germ cell development in terms of tumor biology. Furthermore, data from mice reveal that germline cells display an epigenetic signature, which is highly similar to pluripotent cells. This signature (poised histone code, DNA hypomethylation) is required for the rapid induction of toti- and pluripotency upon fertilization. We propose that adult spermatogonial cells, when exposed to endocrine disruptors or epigenetic active substances, are prone to reinitiate the pluripotency program, giving rise to a germ cell tumor. The fact that pluripotent cells can be derived from adult murine and human testicular cells further corroborates this idea. PMID:27512122

  14. Tissue Interactions Regulating Tooth Development and Renewal.

    PubMed

    Balic, Anamaria; Thesleff, Irma

    2015-01-01

    Reciprocal interactions between epithelial and mesenchymal tissues play a fundamental role in the morphogenesis of teeth and regulate all aspects of tooth development. Extensive studies on mouse tooth development over the past 25 years have uncovered the molecular details of the signaling networks mediating these interactions (reviewed by Jussila & Thesleff, 2012; Lan, Jia, & Jiang, 2014). Five conserved signaling pathways, namely, the Wnt, BMP, FGF, Shh, and Eda, are involved in the mediation of the successive reciprocal epithelial-mesenchymal cross talk which follows the general principle of morphogenetic interactions (Davidson, 1993). The pathways regulate the expression of transcription factors which confer the identity of dental epithelium and mesenchyme. The signals and transcription factors are integrated in complex signaling networks whose fine-tuning allows the generation of the variation in tooth morphologies. In this review, we describe the principles and molecular mechanisms of the epithelial-mesenchymal interactions regulating successive stages of tooth formation: (i) the initiation of tooth development, with special reference to the shift of tooth-forming potential from epithelium to mesenchyme; (ii) the morphogenesis of the tooth crown, focusing on the roles of epithelial signaling centers; (iii) the differentiation of odontoblasts and ameloblasts, which produce dentin and enamel, respectively; and (iv) the maintenance of dental stem cells, which support the continuous growth of teeth. PMID:26589925

  15. Coordination of tooth morphogenesis and neuronal development through tissue interactions: lessons from mouse models.

    PubMed

    Luukko, Keijo; Kettunen, Päivi

    2014-07-15

    In addition to being an advantageous model to investigate general molecular mechanisms of organ formation, the tooth is a distinct target organ for peripheral nerve innervation. These nerves are required for the function and protection of the teeth and, as shown in fish, also for their regeneration. This review focuses on recent findings of the local tissue interactions and molecular signaling mechanisms that regulate the early nerve arrival and patterning of mouse mandibular molar tooth sensory innervation. Dental sensory nerve growth and patterning is a stepwise process that is intimately linked to advancing tooth morphogenesis. In particular, nerve growth factor and semaphorin 3A serve as essential functions during and are iteratively used at different stages of tooth innervation. The tooth germ controls development of its own nerve supply, and similar to the development of the tooth organ proper, tissue interactions between dental epithelial and mesenchymal tissues control the establishment of tooth innervation. Tgf-β, Wnt, and Fgf signaling, which regulate tooth formation, are implicated to mediate these interactions. Therefore, tissue interactions mediated by conserved signal families may constitute key mechanism for the integration of tooth organogenesis and development of its peripheral nerve supply. PMID:24631295

  16. Human tooth germ stem cell response to calcium-silicate based endodontic cements

    PubMed Central

    PAMUKÇU GÜVEN, Esra; YALVAÇ, Mehmet Emir; KAYAHAN, Mehmet Baybora; SUNAY, Hakkı; ŞAHİN, Fikrettin; BAYIRLI, Gündüz

    2013-01-01

    Objective The aim of this study was to compare the cytotoxic effects of endodontic cements on human tooth germ stem cells (hTGSCs). MTA Fillapex, a mineral trioxide aggregate (MTA)-based, salicylate resin containing root canal sealer, was compared with iRoot SP, a bioceramic sealer, and AH Plus Jet, an epoxy resin-based root canal sealer. Material and Methods To evaluate cytotoxicity, all materials were packed into Teflon rings (4 mmµ3 mm) and co-cultured with hTGSCs with the aid of 24-well Transwell permeable supports, which had a pore size of 0.4 µm. Coverslips were coated with MTA Fillapex, iRoot SP and AH Plus Jet and each coverslip was placed onto the bottom of one well of a six-well plate for scanning electron microscopy (SEM) analysis. Before the cytotoxicity and SEM analysis, all samples were stored at 37ºC and at 95% humidity and 5% CO2 for 24 hours to set. The cellular viability was analyzed using MTS test (3-(4,5-dimethyl-thiazol-2-yl)-5-(3-carboxy-methoxy-phenyl)-2-(4-sulfo-phenyl)-2H-tetrazolium). The cytotoxic effects and SEM visualization of the tested materials were analyzed at 24-hour, 72-hour, one-week and two-week periods. Results On the 1st day, only MTA Fillapex caused cytotoxicity compared to negative control (NC) group (p<0.008). No significant difference was observed between the other tested materials at this period (p>0.05). After 14 days of incubation with the test materials, MTA Fillapex exhibited significantly higher cytotoxicity compared with iRoot SP, AH Plus Jet and the NC group (P<0.008). In the SEM analysis, the highest levels of cell attachment were observed for iRoot SP and the control group. After 24 hours, MTA Fillapex reduced the number of cells attached to the surface. Conclusions Within the limitations of this study, sealers exerted different cytotoxic effects on hTGSCs. Although all materials have exerted cellular toxicity, iRoot SP and AH Plus Jet may promote better attachment to hTGSCs. PMID:24037075

  17. On the development of extragonadal and gonadal human germ cells

    PubMed Central

    Heeren, A. Marijne; He, Nannan; de Souza, Aline F.; Goercharn-Ramlal, Angelique; van Iperen, Liesbeth; Roost, Matthias S.; Gomes Fernandes, Maria M.; van der Westerlaken, Lucette A. J.; Chuva de Sousa Lopes, Susana M.

    2016-01-01

    ABSTRACT Human germ cells originate in an extragonadal location and have to migrate to colonize the gonadal primordia at around seven weeks of gestation (W7, or five weeks post conception). Many germ cells are lost along the way and should enter apoptosis, but some escape and can give rise to extragonadal germ cell tumors. Due to the common somatic origin of gonads and adrenal cortex, we investigated whether ectopic germ cells were present in the human adrenals. Germ cells expressing DDX4 and/or POU5F1 were present in male and female human adrenals in the first and second trimester. However, in contrast to what has been described in mice, where ‘adrenal’ and ‘ovarian’ germ cells seem to enter meiosis in synchrony, we were unable to observe meiotic entry in human ‘adrenal’ germ cells until W22. By contrast, ‘ovarian’ germ cells at W22 showed a pronounced asynchronous meiotic entry. Interestingly, we observed that immature POU5F1+ germ cells in both first and second trimester ovaries still expressed the neural crest marker TUBB3, reminiscent of their migratory phase. Our findings highlight species-specific differences in early gametogenesis between mice and humans. We report the presence of a population of ectopic germ cells in the human adrenals during development. PMID:26834021

  18. Germ line development: lessons learned from pluripotent stem cells.

    PubMed

    Martínez-Arroyo, Ana M; Medrano, Jose V; Remohí, José; Simón, Carlos

    2014-10-01

    Current knowledge about mammalian germ line development is mainly based on the mouse model and little is known about how this fundamental process occurs in humans. This review summarizes our current knowledge of genetic and epigenetic germ line development in mammals, mainly focusing on primordial germ cell (PGC) specification events, comparing the differences between mouse and human models. We also emphasize the knowledge derived from the most successful strategies used to generate germ cell-like cells in vitro in both models and major obstacles to obtaining bona fide in vitro-derived gametes are considered. PMID:25461452

  19. [Tooth germ transplantation or gap closure--a comparative study in the loss of the first molar].

    PubMed

    Bauer, W; Wehrbein, H; Schulte-Lünzum, H; Diedrich, P

    1991-04-01

    In our study 37 transplanted and 33 mesialized molars by orthodontics were clinically and radiologically compared. The teeth moved by orthodontics showed a better long-term prognosis. As vital teeth with functioning periodontal structures and only slightly shortened roots they were equivalent to healthy teeth. However, the disadvantage of orthodontic space closure is the requirement of a good compliance due to long treatment time. The prognosis of maintaining a transplanted tooth germ is uncertain. One third of the teeth showed an altered periodontium with resorption areas. The danger of a continuing resorption, as well as a late external resorption is still a risk after a long period of time and can eventually lead to tooth loss. As a treatment alternative, germ transplantation may serve as a replacement of a single missing 6-year-molar in adolescence. Orthodontic space closure is indicated at any age with an existing dysgnathia, the loss of several first molars, the loss of space and mesial tipping of the second molars. PMID:2066041

  20. Differential expression of decorin and biglycan genes during mouse tooth development

    NASA Technical Reports Server (NTRS)

    Matsuura, T.; Duarte, W. R.; Cheng, H.; Uzawa, K.; Yamauchi, M.

    2001-01-01

    Small leucine-rich proteoglycans (SLRPs) have a number of biological functions and some of them are thought to regulate collagen mineralizaton in bone and tooth. We have previously identified and immunolocalized two members of the SLRPs family, decorin and biglycan, in bovine tooth/periodontium. To investigate their potential roles in tooth development, we examined the mRNA expression patterns of decorin, biglycan and type I collagen in newborn (day 19) mice tooth germs by in situ hybridization. At this developmental stage, the first maxillary and mandibular molars include stages before and after secretion of the predentin matrix, respectively. The expression of decorin mRNA coincided with that of type I collagen mRNA and was mostly observed in secretory odontoblasts, while the biglycan mRNA was expressed throughout the tooth germ, including pre-secretory odontoblasts/ameloblasts, dental papilla and stellate reticulum. However, its signal in secretory odontoblasts was not as evident as that of decorin. In mandibular incisors, where a significant amount of predentin matrix and a small amount of enamel matrix were already secreted, a similar differential expression pattern was observed. In secretory ameloblasts the biglycan mRNA expression was apparent, while that of decorin was not. These differential expression patterns suggest the distinct roles of biglycan and decorin in the process of tooth development.

  1. Hedgehog signaling is required at multiple stages of zebrafish tooth development

    PubMed Central

    2010-01-01

    Background The accessibility of the developing zebrafish pharyngeal dentition makes it an advantageous system in which to study many aspects of tooth development from early initiation to late morphogenesis. In mammals, hedgehog signaling is known to be essential for multiple stages of odontogenesis; however, potential roles for the pathway during initiation of tooth development or in later morphogenesis are incompletely understood. Results We have identified mRNA expression of the hedgehog ligands shha and the receptors ptc1 and ptc2 during zebrafish pharyngeal tooth development. We looked for, but did not detect, tooth germ expression of the other known zebrafish hedgehog ligands shhb, dhh, ihha, or ihhb, suggesting that as in mammals, only Shh participates in zebrafish tooth development. Supporting this idea, we found that morphological and gene expression evidence of tooth initiation is eliminated in shha mutant embryos, and that morpholino antisense oligonucleotide knockdown of shha, but not shhb, function prevents mature tooth formation. Hedgehog pathway inhibition with the antagonist compound cyclopamine affected tooth formation at each stage in which we applied it: arresting development at early stages and disrupting mature tooth morphology when applied later. These results suggest that hedgehog signaling is required continuously during odontogenesis. In contrast, over-expression of shha had no effect on the developing dentition, possibly because shha is normally extensively expressed in the zebrafish pharyngeal region. Conclusion We have identified previously unknown requirements for hedgehog signaling for early tooth initiation and later morphogenesis. The similarity of our results with data from mouse and other vertebrates suggests that despite gene duplication and changes in the location of where teeth form, the roles of hedgehog signaling in tooth development have been largely conserved during evolution. PMID:21118524

  2. A germ cell determinant reveals parallel pathways for germ line development in Caenorhabditis elegans.

    PubMed

    Mainpal, Rana; Nance, Jeremy; Yanowitz, Judith L

    2015-10-15

    Despite the central importance of germ cells for transmission of genetic material, our understanding of the molecular programs that control primordial germ cell (PGC) specification and differentiation are limited. Here, we present findings that X chromosome NonDisjunction factor-1 (XND-1), known for its role in regulating meiotic crossover formation, is an early determinant of germ cell fates in Caenorhabditis elegans. xnd-1 mutant embryos display a novel 'one PGC' phenotype as a result of G2 cell cycle arrest of the P4 blastomere. Larvae and adults display smaller germ lines and reduced brood size consistent with a role for XND-1 in germ cell proliferation. Maternal XND-1 proteins are found in the P4 lineage and are exclusively localized to the nucleus in PGCs, Z2 and Z3. Zygotic XND-1 turns on shortly thereafter, at the ∼300-cell stage, making XND-1 the earliest zygotically expressed gene in worm PGCs. Strikingly, a subset of xnd-1 mutants lack germ cells, a phenotype shared with nos-2, a member of the conserved Nanos family of germline determinants. We generated a nos-2 null allele and show that nos-2; xnd-1 double mutants display synthetic sterility. Further removal of nos-1 leads to almost complete sterility, with the vast majority of animals without germ cells. Sterility in xnd-1 mutants is correlated with an increase in transcriptional activation-associated histone modification and aberrant expression of somatic transgenes. Together, these data strongly suggest that xnd-1 defines a new branch for PGC development that functions redundantly with nos-2 and nos-1 to promote germline fates by maintaining transcriptional quiescence and regulating germ cell proliferation. PMID:26395476

  3. Development without germ cells: the role of the germ line in zebrafish sex differentiation.

    PubMed

    Slanchev, Krasimir; Stebler, Jürg; de la Cueva-Méndez, Guillermo; Raz, Erez

    2005-03-15

    The progenitors of the gametes, the primordial germ cells (PGCs) are typically specified early in the development in positions, which are distinct from the gonad. These cells then migrate toward the gonad where they differentiate into sperms and eggs. Here, we study the role of the germ cells in somatic development and particularly the role of the germ line in the sex differentiation in zebrafish. To this end, we ablated the germ cells using two independent methods and followed the development of the experimental fish. First, PGCs were ablated by knocking down the function of dead end, a gene important for the survival of this lineage. Second, a method to eliminate the PGCs using the toxin-antitoxin components of the parD bacterial genetic system was used. Specifically, we expressed a bacterial toxin Kid preferentially in the PGCs and at the same time protected somatic cells by uniformly expressing the specific antidote Kis. Our results demonstrate an unexpected role for the germ line in promoting female development because PGC-ablated fish invariably developed as males. PMID:15728735

  4. Development without germ cells: The role of the germ line in zebrafish sex differentiation

    PubMed Central

    Slanchev, Krasimir; Stebler, Jürg; de la Cueva-Méndez, Guillermo; Raz, Erez

    2005-01-01

    The progenitors of the gametes, the primordial germ cells (PGCs) are typically specified early in the development in positions, which are distinct from the gonad. These cells then migrate toward the gonad where they differentiate into sperms and eggs. Here, we study the role of the germ cells in somatic development and particularly the role of the germ line in the sex differentiation in zebrafish. To this end, we ablated the germ cells using two independent methods and followed the development of the experimental fish. First, PGCs were ablated by knocking down the function of dead end, a gene important for the survival of this lineage. Second, a method to eliminate the PGCs using the toxin–antitoxin components of the parD bacterial genetic system was used. Specifically, we expressed a bacterial toxin Kid preferentially in the PGCs and at the same time protected somatic cells by uniformly expressing the specific antidote Kis. Our results demonstrate an unexpected role for the germ line in promoting female development because PGC-ablated fish invariably developed as males. PMID:15728735

  5. Origin and development of the germ line in sea stars.

    PubMed

    Wessel, Gary M; Fresques, Tara; Kiyomoto, Masato; Yajima, Mamiko; Zazueta, Vanesa

    2014-05-01

    This review summarizes and integrates our current understanding of how sea stars make gametes. Although little is known of the mechanism of germ line formation in these animals, recent results point to specific cells and to cohorts of molecules in the embryos and larvae that may lay the ground work for future research efforts. A coelomic outpocketing forms in the posterior of the gut in larvae, referred to as the posterior enterocoel (PE), that when removed, significantly reduces the number of germ cell later in larval growth. This same PE structure also selectively accumulates several germ-line associated factors-vasa, nanos, piwi-and excludes factors involved in somatic cell fate. Since its formation is relatively late in development, these germ cells may form by inductive mechanisms. When integrated into the morphological observations of germ cells and gonad development in larvae, juveniles, and adults, the field of germ line determination appears to have a good model system to study inductive germ line determination to complement the recent work on the molecular mechanisms in mice. We hope this review will also guide investigators interested in germ line determination and regulation of the germ line into how these animals can help in this research field. The review is not intended to be comprehensive-sea star reproduction has been studied for over 100 years and many reviews are comprehensive in their coverage of, for example, seasonal growth of the gonads in response to light, nutrient, and temperature. Rather the intent of this review is to help the reader focus on new experimental results attached to the historical underpinnings of how the germ cell functions in sea stars with particular emphasis to clarify the important areas of priority for future research. PMID:24648114

  6. Development of malignant germ cells - the genvironmental hypothesis.

    PubMed

    Looijenga, Leendert H J; Van Agthoven, Ton; Biermann, Katharina

    2013-01-01

    Human germ cell tumors are of interest because of their epidemiology, clinic and patho-biology. Histologically, they are subdivided into various elements, with similarities to embryogenesis. Recent insight triggered development of a higher order division into five types of human germ cell tumors. In the context of male germ cells, only three are relevant; Type I: teratomas and yolk sac tumors of neonates and infants; Type II: seminomas and nonseminomas of (predominantly) adolescents and adults; and Type III: spermatocytic seminomas of the elderly. Various animal models, both occurring spontaneous or induced, are reported, of which their relevance is still a matter of debate. Recent multidisciplinary studies have led to a significant increase in our understanding of the parameters involved in the earliest pathogenetic steps of human germ cells tumors, particularly the seminomas and nonseminomas (Type II). This paper will discuss a number of interesting insights into the normal and aberrant regulation of germ cell development, resulting in the so-called genvironmental hypothesis. This assumes a subtle interaction between environmental- and (epi)genetic parameters, resulting in clinical/phenotypical characteristics. These influence signaling pathways and thereby developmental processes, including gonadal development, germ cell proliferation, maturation and apoptosis. In the case of a disturbed physiology, either due to the germ cell itself, or the micro-environment, embryonic germ cells, during a specific window of sensitization, might be blocked in their maturation, resulting in carcinoma in situ or gonadoblastoma, the precursors of seminomas and nonseminomas. The level of testicularization of the gonad determines the histological composition of the precursor. These insights will allow a better definition of individuals at risk of developing a germ cell malignancy, and allow a better selection of scientific approaches to elucidate the corresponding pathogenesis. PMID

  7. Dynamic expression of Six family genes in the dental mesenchyme and the epithelial ameloblast stem/progenitor cells during murine tooth development

    PubMed Central

    Nonomura, Koji; Takahashi, Masanori; Wakamatsu, Yoshio; Takano-Yamamoto, Teruko; Osumi, Noriko

    2010-01-01

    Six family transcription factor genes play multiple and crucial roles in the development of the vertebrate sensory system including the eye, olfactory epithelium and otic vesicle, and these genes are highly expressed in the neural crest-derived cranial mesenchymal cells in the mouse embryo. However, expression patterns have yet to be determined for the Six family genes in the developing tooth germ. In this study, we examined expression of six members of the Six family genes in the dental mesenchyme and the dental epithelium of the developing tooth germs in mice by in situ hybridization. We found dynamic expression patterns for Six1, Six2, Six4 and Six5 in the oral epithelium and mesenchymal cells with distinct expression patterns at the early stage before invagination of the dental epithelium. In addition, expression of Six1 and Six4 was observed in the inner enamel epithelium of the incisor and molar tooth germs at the cap stage. Expression of Six5 was maintained in the bell stage tooth germs, and intense expression of Six1 and Six4 was detected not only in the mesenchyme-derived dental follicle but also in the proliferating inner enamel epithelium of the labial cervical loop of the incisor tooth germ. Taken together, our results suggest that dynamic expression of Six family genes represents specific stages of the developing tooth germ. This dynamic expression is embodied in changes in both space and over time, and these changes in expression suggest that Six family genes may participate in tooth germ morphogenesis and the proliferation and/or differentiation of the incisor ameloblast stem/progenitor cells. PMID:19900183

  8. Spatiotemporal expression of caveolin-1 and EMMPRIN during mouse tooth development.

    PubMed

    Shi, Lu; Li, Lingyun; Wang, Ding; Li, Shu; Chen, Zhi; An, Zhengwen

    2016-06-01

    Caveolin-1 is a scaffolding protein involved in the formation of cholesterol-rich caveolae lipid rafts within the plasma membrane and is capable of collecting signaling molecules into the caveolae and regulating their activity, including extracellular matrix metalloproteinase inducer (EMMPRIN). However, detailed expression patterns of caveolin-1 and EMMPRIN in the developing dental germ are largely unknown. The present study investigated the expression patterns of caveolin-1 and EMMPRIN in the developing mouse tooth germ by immunohistochemistry and real-time polymerase chain reaction. At the bud stage, caveolin-1 expression was initiated in the epithelium bud and mesenchymal cells, while EMMPRIN was weakly expressed at this stage. At the cap stage, caveolin-1 protein was located in the lingual part of the tooth germ; however, EMMPRIN protein was located in the labial part. From the bell stage to 2 days postnatal, caveolin-1 expression was detected in the ameloblasts and cervical loop area; with EMMPRIN expression in the ameloblasts and odontoblasts. Real-time polymerase chain reaction results showed that both caveolin-1 and EMMPRIN mRNA levels increased gradually with progression of developmental stages, and peaked at day two postnatal. The current finding suggests that both caveolin-1 and EMMPRIN take part in mouse tooth development, especially in the differentiation and organization of odontogenic tissues. PMID:27075451

  9. Topology of the germ plasm and development of primordial germ cells in inverted amphibian eggs

    NASA Technical Reports Server (NTRS)

    Wakahara, M.; Neff, A. W.; Malacinski, G. M.

    1984-01-01

    Inverted Xenopus eggs have reduced numbers of primordial germ cells (PGCs). The extent of the reduction varies from spawning to spawning. Histologic examination revealed that PGC counts were lowest in inverted eggs which displayed the greatest amount of shift in the vegetal mass of large yolk platelets, although the germ plasm itself always remained localized in the egg's original vegetal hemisphere. Even at blastulation the germ plasm continued to be localized in the egg's original vegetal hemisphere. In many cases, however, it was confined to the periphery of the embryo, which probably accounts for the reduced PGC number in some tadpoles. In other cases it may have been dispersed and therefore not detectable in histologic analyses. Although the altered site of involution in inverted embryos did not influence PGC development, subsequent cell movement patterns apparently did. Those embryos which displayed the largest degree of pattern reversal at the tail-bud stage also exhibited the most extreme reduction in PGC numbers. A brief cold shock (4 degrees C, 10 min) prior to first cleavage leads to a further reduction in PGC numbers in inverted embryos, probably as a result of the displacement of the germ plasm away from its original vegetal pole location.

  10. Antagonistic Functions of USAG-1 and RUNX2 during Tooth Development.

    PubMed

    Togo, Yumiko; Takahashi, Katsu; Saito, Kazuyuki; Kiso, Honoka; Tsukamoto, Hiroko; Huang, Boyen; Yanagita, Motoko; Sugai, Manabu; Harada, Hidemitsu; Komori, Toshihisa; Shimizu, Akira; MacDougall, Mary; Bessho, Kazuhisa

    2016-01-01

    Supernumerary teeth and tooth agenesis are common morphological anomalies in humans. We previously obtained evidence that supernumerary maxillary incisors form as a result of the successive development of the rudimentary maxillary incisor tooth germ in Usag-1 null mice. The development of tooth germs is arrested in Runx2 null mice, and such mice also exhibit lingual epithelial buds associated with the upper molars and incisors. The aim of this study is to investigate the potential crosstalk between Usag-1 and Runx2 during tooth development. In the present study, three interesting phenomena were observed in double null Usag-1-/-/Runx2-/- mice: the prevalence of supernumerary teeth was lower than in Usag-1 null mice; tooth development progressed further compared than in Runx2 null mice; and the frequency of molar lingual buds was lower than in Runx2 null mice. Therefore, we suggest that RUNX2 and USAG-1 act in an antagonistic manner. The lingual bud was completely filled with odontogenic epithelial Sox2-positive cells in the Usag-1+/+/Runx2-/- mice, whereas almost no odontogenic epithelial Sox2-positive cells contributed to supernumerary tooth formation in the rudimentary maxillary incisors of the Usag-1-/-/Runx2+/+ mice. Our findings suggest that RUNX2 directly or indirectly prevents the differentiation and/or proliferation of odontogenic epithelial Sox2-positive cells. We hypothesize that RUNX2 inhibits the bone morphogenetic protein (BMP) and/or Wnt signaling pathways regulated by USAG-1, whereas RUNX2 expression is induced by BMP signaling independently of USAG-1. PMID:27518316

  11. Antagonistic Functions of USAG-1 and RUNX2 during Tooth Development

    PubMed Central

    Togo, Yumiko; Takahashi, Katsu; Saito, Kazuyuki; Kiso, Honoka; Tsukamoto, Hiroko; Huang, Boyen; Yanagita, Motoko; Sugai, Manabu; Harada, Hidemitsu; Komori, Toshihisa; Shimizu, Akira; MacDougall, Mary; Bessho, Kazuhisa

    2016-01-01

    Supernumerary teeth and tooth agenesis are common morphological anomalies in humans. We previously obtained evidence that supernumerary maxillary incisors form as a result of the successive development of the rudimentary maxillary incisor tooth germ in Usag-1 null mice. The development of tooth germs is arrested in Runx2 null mice, and such mice also exhibit lingual epithelial buds associated with the upper molars and incisors. The aim of this study is to investigate the potential crosstalk between Usag-1 and Runx2 during tooth development. In the present study, three interesting phenomena were observed in double null Usag-1-/-/Runx2-/- mice: the prevalence of supernumerary teeth was lower than in Usag-1 null mice; tooth development progressed further compared than in Runx2 null mice; and the frequency of molar lingual buds was lower than in Runx2 null mice. Therefore, we suggest that RUNX2 and USAG-1 act in an antagonistic manner. The lingual bud was completely filled with odontogenic epithelial Sox2-positive cells in the Usag-1+/+/Runx2-/- mice, whereas almost no odontogenic epithelial Sox2-positive cells contributed to supernumerary tooth formation in the rudimentary maxillary incisors of the Usag-1-/-/Runx2+/+ mice. Our findings suggest that RUNX2 directly or indirectly prevents the differentiation and/or proliferation of odontogenic epithelial Sox2-positive cells. We hypothesize that RUNX2 inhibits the bone morphogenetic protein (BMP) and/or Wnt signaling pathways regulated by USAG-1, whereas RUNX2 expression is induced by BMP signaling independently of USAG-1. PMID:27518316

  12. Perspectives of germ cell development in vitro in mammals

    PubMed Central

    Hayashi, Katsuhiko; Saitou, Mitinori

    2014-01-01

    Pluripotent stem cells, such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are able to differentiate into all cell lineages of the embryo proper, including germ cells. This pluripotent property has a huge impact on the fields of regenerative medicine, developmental biology and reproductive engineering. Establishing the germ cell lineage from ESCs/iPSCs is the key biological subject, since it would contribute not only to dissection of the biological processes of germ cell development but also to production of unlimited numbers of functional gametes in vitro. Toward this goal, we recently established a culture system that induces functional mouse primordial germ cells (PGCs), precursors of all germ cells, from mouse ESCs/iPSCs. The successful in vitro production of PGCs arose from the study of pluripotent cell state, the signals inducing PGCs and the technology of transplantation. However, there are many obstacles to be overcome for the robust generation of mature gametes or for application of the culture system to other species, including humans and livestock. In this review, we discuss the requirements for a culture system to generate the germ cell lineage from ESCs/iPSCs. PMID:24725251

  13. Fate of HERS during Tooth Root Development

    PubMed Central

    Huang, Xiaofeng; Bringas, Pablo; Slavkin, Harold C.; Chai, Yang

    2009-01-01

    Tooth root development begins after the completion of crown formation in mammals. Previous studies have shown that Hertwig's epithelial root sheath (HERS) plays an important role in root development, but the fate of HERS has remained unknown. In order to investigate the morphological fate and analyze the dynamic movement of HERS cells in vivo, we generated K14-Cre;R26R mice. HERS cells are detectable on the surface of the root throughout root formation and do not disappear. Most of the HERS cells are attached to the surface of the cementum, and others separate to become the epithelial rest of Malasez. HERS cells secrete extracellular matrix components onto the surface of the dentin before dental follicle cells penetrate the HERS network to contact dentin. HERS cells also participate in the cementum development and may differentiate into cementocytes. During root development, the HERS is not interrupted, and instead the HERS cells continue to communicate with each other through the network structure. Furthermore, HERS cells interact with cranial neural crest derived mesenchyme to guide root development. Taken together, the network of HERS cells is crucial for tooth root development. PMID:19576204

  14. Germ Cell Nuclear Factor Regulates Gametogenesis in Developing Gonads

    PubMed Central

    Sabour, Davood; Xu, Xueping; Chung, Arthur C. K.; Le Menuet, Damien; Ko, Kinarm; Tapia, Natalia; Araúzo-Bravo, Marcos J.; Gentile, Luca; Greber, Boris; Hübner, Karin; Sebastiano, Vittorio; Wu, Guangming; Schöler, Hans R.; Cooney, Austin J.

    2014-01-01

    Expression of germ cell nuclear factor (GCNF; Nr6a1), an orphan member of the nuclear receptor gene family of transcription factors, during gastrulation and neurulation is critical for normal embryogenesis in mice. Gcnf represses the expression of the POU-domain transcription factor Oct4 (Pou5f1) during mouse post-implantation development. Although Gcnf expression is not critical for the embryonic segregation of the germ cell lineage, we found that sexually dimorphic expression of Gcnf in germ cells correlates with the expression of pluripotency-associated genes, such as Oct4, Sox2, and Nanog, as well as the early meiotic marker gene Stra8. To elucidate the role of Gcnf during mouse germ cell differentiation, we generated an ex vivo Gcnf-knockdown model in combination with a regulated CreLox mutation of Gcnf. Lack of Gcnf impairs normal spermatogenesis and oogenesis in vivo, as well as the derivation of germ cells from embryonic stem cells (ESCs) in vitro. Inactivation of the Gcnf gene in vivo leads to loss of repression of Oct4 expression in both male and female gonads. PMID:25140725

  15. Fus Expression Patterns in Developing Tooth

    PubMed Central

    Kim, Eun-Jung; Lee, Jong-Min; Jung, Han-Sung

    2013-01-01

    Recently, the RNA/DNA-binding protein FUS, Fused in sarcoma, was shown to play a role in growth, differentiation, and morphogenesis in vertebrates. Because little is known about Fus, we investigated its expression pattern in murine tooth development. In situ hybridization of mouse mandibles at specific developmental stages was performed with a DIG-labeled RNA probe. During early tooth development, Fus was detected in the dental epithelium and dental mesenchyme at 11 days postcoitum (dpc) and 12 dpc. From 14 dpc, Fus was strongly expressed in the dental papilla and the cervical loop of the dental epithelium. At postnatal day 4 (PN4), Fus expression was observed in the odontoblasts, ameloblasts, the proliferation zone of the pulp, and the cervical loop. At PN14, the expression pattern of Fus was found to be maintained in the odontoblasts and the proliferation zone of the pulp. Furthermore, Fus expression was especially strong in the Hertwig’s epithelial root sheath (HERS). Therefore, this study suggests that Fus may play a role in the HERS during root development. PMID:25949136

  16. 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

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

    PubMed

    Miyazaki, Kanako; Yoshizaki, Keigo; 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

  18. Deletion of Osr2 Partially Rescues Tooth Development in Runx2 Mutant Mice.

    PubMed

    Kwon, H J E; Park, E K; Jia, S; Liu, H; Lan, Y; Jiang, R

    2015-08-01

    Tooth organogenesis depends on genetically programmed sequential and reciprocal inductive interactions between the dental epithelium and neural crest-derived mesenchyme. Previous studies showed that the Msx1 and Runx2 transcription factors are required for activation of odontogenic signals, including Bmp4 and Fgf3, in the early tooth mesenchyme to drive tooth morphogenesis through the bud-to-cap transition and that Runx2 acts downstream of Msx1 to activate Fgf3 expression. Recent studies identified Osr2 as a repressor of tooth development and showed that inactivation of Osr2 rescued molar tooth morphogenesis in the Msx1(-/-) mutant mice as well as in mice with neural crest-specific inactivation of Bmp4. Here we show that Runx2 expression is expanded in the tooth bud mesenchyme in Osr2(-/-) mutant mouse embryos and is partially restored in the tooth mesenchyme in Msx1(-/-)Osr2(-/-) mutants in comparison with Msx1(-/-) and wild-type embryos. Whereas mandibular molar development arrested at the bud stage and maxillary molar development arrested at the bud-to-cap transition in Runx2(-/-) mutant mice, both mandibular and maxillary molar tooth germs progressed to the early bell stage, with rescued expression of Msx1 and Bmp4 in the dental papilla as well as expression of Bmp4, p21, and Shh in the primary enamel knot in the Osr2(-/-)Runx2(-/-) compound mutants. In contrast to the Msx1(-/-)Osr2(-/-) compound mutants, which exhibit nearly normal first molar morphogenesis, the Osr2(-/-)Runx2(-/-) compound mutant embryos failed to activate the expression of Fgf3 and Fgf10 in the dental papilla and exhibited significant deficit in cell proliferation in both the dental epithelium and mesenchyme in comparison with the control embryos. These data indicate that Runx2 synergizes with Msx1 to drive tooth morphogenesis through the bud-to-cap transition and that Runx2 controls continued tooth growth and morphogenesis beyond the cap stage through activation of Fgf3 and Fgf10 expression

  19. A functional genomic screen in planarians identifies novel regulators of germ cell development

    PubMed Central

    Wang, Yuying; Stary, Joel M.; Wilhelm, James E.; Newmark, Phillip A.

    2010-01-01

    Germ cells serve as intriguing examples of differentiated cells that retain the capacity to generate all cell types of an organism. Here we used functional genomic approaches in planarians to identify genes required for proper germ cell development. We conducted microarray analyses and in situ hybridization to discover and validate germ cell-enriched transcripts, and then used RNAi to screen for genes required for discrete stages of germ cell development. The majority of genes we identified encode conserved RNA-binding proteins, several of which have not been implicated previously in germ cell development. We also show that a germ cell-specific subunit of the conserved transcription factor CCAAT-binding protein/nuclear factor-Y is required for maintaining spermatogonial stem cells. Our results demonstrate that conserved transcriptional and post-transcriptional mechanisms regulate germ cell development in planarians. These findings suggest that studies of planarians will inform our understanding of germ cell biology in higher organisms. PMID:20844018

  20. PGC-Enriched miRNAs Control Germ Cell Development

    PubMed Central

    Bhin, Jinhyuk; Jeong, Hoe-Su; Kim, Jong Soo; Shin, Jeong Oh; Hong, Ki Sung; Jung, Han-Sung; Kim, Changhoon; Hwang, Daehee; Kim, Kye-Seong

    2015-01-01

    Non-coding microRNAs (miRNAs) regulate the translation of target messenger RNAs (mRNAs) involved in the growth and development of a variety of cells, including primordial germ cells (PGCs) which play an essential role in germ cell development. However, the target mRNAs and the regulatory networks influenced by miRNAs in PGCs remain unclear. Here, we demonstrate a novel miRNAs control PGC development through targeting mRNAs involved in various cellular pathways. We reveal the PGC-enriched expression patterns of nine miRNAs, including miR-10b, -18a, -93, -106b, -126-3p, -127, -181a, -181b, and -301, using miRNA expression analysis along with mRNA microarray analysis in PGCs, embryonic gonads, and postnatal testes. These miRNAs are highly expressed in PGCs, as demonstrated by Northern blotting, miRNA in situ hybridization assay, and miRNA qPCR analysis. This integrative study utilizing mRNA microarray analysis and miRNA target prediction demonstrates the regulatory networks through which these miRNAs regulate their potential target genes during PGC development. The elucidated networks of miRNAs disclose a coordinated molecular mechanism by which these miRNAs regulate distinct cellular pathways in PGCs that determine germ cell development. PMID:26442865

  1. Development of germ cell neoplasia in situ in chinchilla rabbits.

    PubMed

    Vigueras-Villaseñor, Rosa María; Montelongo Solís, Paola; Chávez-Saldaña, Margarita; Gutiérrez-Pérez, Oscar; Cortés Trujillo, Lucero; Rojas-Castañeda, Julio César

    2016-05-01

    The present study was designed to describe the development of germ cell neoplasia in situ in Chinchilla rabbit by administration of estradiol. The study was performed in rabbits distributed into two groups: control and 17 β-estradiol. The determination of histological alterations and POU5F1 and c-kit proteins employed as biomarkers for the diagnosis of this neoplasia was carried out. Testicular descent and complete spermatogenesis were observed in the control group. The protein biomarkers were negative. However, in the rabbits treated with estradiol, the testes remained undescended with the gonocytes undifferentiated to spermatogonia. There were histological lesions owing to germ cell neoplasia in situ and positive to POU5F1 and c-kit proteins. These findings indicate that the chinchilla rabbit is an ideal model to study this neoplasia in which the histological characteristics and biomarkers of the disease could be clearly observed. Using this model we suggested that the persisting gonocytes could be responsible for the development of germ cell neoplasia in situ. PMID:26617392

  2. Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta

    PubMed Central

    Zahradnicek, Oldrich; Horacek, Ivan; Tucker, Abigail S

    2012-01-01

    This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. Here we document the dental pattern and development of non-functional (null generation) and functional generations of teeth during embryonic development. Tooth development is followed from initiation to cytodifferentiation and ankylosis, as the tooth germs develop from bud, through cap to bell stages. The fate of the single generation of non-functional (null generation) teeth is shown to be variable, with some teeth being expelled from the oral cavity, while others are incorporated into the functional bone and teeth, or are absorbed. Fate appears to depend on the initiation site within the oral cavity, with the first null generation teeth forming before formation of the dental lamina. We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals. PMID:22780101

  3. Selective accumulation of germ-line associated gene products in early development of the sea star and distinct differences from germ-line development in the sea urchin

    PubMed Central

    Fresques, Tara; Zazueta-Novoa, Vanesa; Reich, Adrian; Wessel, Gary M.

    2014-01-01

    Background Echinodermata is a diverse Phylum, a sister group to chordates, and contains diverse organisms that may be useful to understand varied mechanisms of germ-line specification. Results We tested 23 genes in development of the sea star Patiria miniata that fall into five categories: 1) Conserved germ-line factors; 2) Genes involved in the inductive mechanism of germ-line specification; 3) Germ-line associated genes; 4) Molecules involved in left-right asymmetry; and 5) Genes involved in regulation and maintenance of the genome during early embryogenesis. Overall, our results support the contention that the posterior enterocoel is a source of the germ line in the sea star P. miniata. Conclusion The germ line in this organism appears to be specified late in embryogenesis, and in a pattern more consistent with inductive interactions amongst cells. This is distinct from the mechanism seen in sea urchins, a close relative of the sea star clad. We propose that P. miniata may serve as a valuable model to study inductive mechanisms of germ-cell specification and when compared to germ-line formation in the sea urchin S. purpuratus may reveal developmental transitions that occur in the evolution of inherited and inductive mechanisms of germ-line specification. PMID:24038550

  4. The role of dead-end in germ-cell tumor development.

    PubMed

    Zhu, Rui; Bhattacharya, Chitralekha; Matin, Angabin

    2007-12-01

    Testicular germ-cell tumors occur in human males of all age groups, from infants to men over 50 years old. Most commonly, germ-cell tumors (generally known as testicular cancer) occur in young males between the ages of 15 to 35 years. The tumor tissues are usually histologically diverse, and testicular tumors that occur in the different age groups tend to be of specific histological subtypes. Most germ-cell tumors originate from primordial germ cells during embryonic development, although the progression and eventual detection of the disease occurs decades later in humans. Mouse strains spontaneously develop a specific subtype of testicular germ-cell tumors, the type I germ-cell tumors, and these tumors are similar to the germ-cell tumors (or teratomas) that occur in human infants. Some mouse strains, such as the 129-Ter strain, have extremely high germ-cell tumor incidences, making such strains ideal for genetic and biological studies of germ cell-tumor development. Here a brief overview of the recently identified genetic defect in the Ter strain, inactivation of the dead-end (Dnd1) gene, and the ongoing studies on Dnd1 to understand its role in germ-cell and germ cell-tumor development, are provided. PMID:17905939

  5. Models of germ cell development and their application for toxicity studies.

    PubMed

    Ferreira, Daniel W; Allard, Patrick

    2015-10-01

    Germ cells are unique in their ability to transfer genetic information and traits from generation to generation. As such, the proper development of germ cells and the integrity of their genome are paramount to the health of organisms and the survival of species. Germ cells are also exquisitely sensitive to environmental influences although the testing of germ cell toxicity, especially in females, has proven particularly challenging. In this review, we first describe the remarkable odyssey of germ cells in mammals, with an emphasis on the female germline, from their initial specification early during embryogenesis to the generation of mature gametes in adults. We also describe the current methods used in germ cell toxicity testing and their limitations in examining the complex features of mammalian germ cell development. To bypass these challenges, we propose the use of alternative model systems such as Saccharomyces cerevisiae, Drosophila melanogaster, Caenorhabditis elegans, and in vitro germ cell methods that have distinct advantages over traditional toxicity models. We discuss the benefits and limitations of each approach, their application to germ cell toxicity studies, and the need for computational approaches to maximize the usefulness of these models. Together, the inclusion of these alternative germ cell toxicity models will be invaluable for the examination of stages not easily accessible in mammals as well as the large scale, high-throughput investigation of germ cell toxicity. PMID:25821157

  6. Chemerin-ChemR23 Signaling in Tooth Development

    PubMed Central

    Ohira, T.; Spear, D.; Azimi, N.; Andreeva, V.; Yelick, P.C.

    2012-01-01

    Our long-term goal is to identify and characterize molecular mechanisms regulating tooth development, including those mediating the critical dental epithelial-dental mesenchymal (DE-DM) cell interactions required for normal tooth development. The goal of this study was to investigate Chemerin (Rarres2)/ChemR23(Cmklr1) signaling in DE-DM cell interactions in normal tooth development. Here we present, for the first time, tissue-specific expression patterns of Chemerin and ChemR23 in mouse tooth development. We show that Chemerin is expressed in cultured DE progenitor cells, while ChemR23 is expressed in cultured DM cells. Moreover, we demonstrate that ribosomal protein S6 (rS6) and Akt, downstream targets of Chemerin/ChemR23 signaling, are phosphorylated in response to Chemerin/ChemR23 signaling in vitro and are expressed in mouse tooth development. Together, these results suggest roles for Chemerin/ChemR23-mediated DE-DM cell signaling during tooth morphogenesis. PMID:23053848

  7. FHL2 mediates tooth development and human dental pulp cell differentiation into odontoblasts, partially by interacting with Runx2.

    PubMed

    Du, Jianxin; Wang, Qiang; Yang, Pishan; Wang, Xiaoying

    2016-04-01

    The differentiation of mesenchymal cells in tooth germ and dental pulp cells into odontoblasts is crucial for dentin formation, and the transcription factor runt-related transcription factor (Runx2) is necessary for odontoblast differentiation. Our previous study demonstrated that four and a half LIM domains 2 (FHL2) may play an important role in tooth development and human dental pulp cell differentiation. This study aimed to determine whether FHL2 mediated the mesenchymal cells in tooth development and human dental pulp cell differentiation into odontoblasts by interacting with Runx2. The expression patterns of FHL2 and Runx2 were examined at the early stages of mouse molar development using double immunofluorescence staining. Western blot analysis and co-immunoprecipitation (Co-IP) were conducted for the preliminary study of the relationship between FHL2 and Runx2 in human dental pulp cell differentiation into odontoblasts. Results of double immunofluorescence staining showed that FHL2 and Runx2 exhibited similar expression patterns at the early stages of tooth development. Western blot analysis indicated that the expression patterns of FHL2 and Runx2 were synchronized on day 7 of induction, whereas those on day 14 differed. Co-IP analysis revealed positive bands of protein complexes, revealing the interaction of FHL2 and Runx2 on days 0, 7 and 14 of induction. Our data suggested that FHL2 might interact with Runx2 to mediate mesenchymal cell differentiation at the early stages of tooth development and human dental pulp cell differentiation. PMID:26759258

  8. Localization of type IV collagen a 1 to a 6 chains in basement membrane during mouse molar germ development.

    PubMed

    Nagai, N; Nakano, K; Sado, Y; Naito, I; Gunduz, M; Tsujigiwa, H; Nagatsuka, H; Ninomiya, Y; Siar, C H

    2001-10-01

    The dental basement membrane (BM) putatively mediates epithelial-mesenchymal interactions during tooth morphogenesis and cytodifferentiation. Type IV collagen alpha chains, a major network-forming protein of the dental BM, was studied and results disclosed distinct expression patterns at different stages of mouse molar germ development. At the dental placode and bud stage, the BM of the oral epithelium expressed alpha 1, alpha 2, alpha 5 and alpha 6 chains while the gubernaculum dentis, in addition to the above four chains, also expressed a 4 chain. An asymmetrical expression for alpha 4, alpha 5 and alpha 6 chains was observed at the bud stage. At the early bell stage, the BM associated with the inner enamel epithelium (IEE) of molar germ expressed alpha 1, alpha 2 and alpha 4 chains while the BM of the outer enamel epithelium (OEE) expressed only alpha 1 and a 2 chains. With the onset of dentinogenesis, the collagen a chain profile of the IEE BM gradually disappeared. Howeverfrom the early to late bell stage, the gubernaculum dentis consistently expressed alpha 1, alpha 2, alpha 5 and a 6 chains resembling fetal oral mucosa. These findings suggest that stage- and position-specific distribution of type IV collagen alpha subunits occur during molar germ development and that these changes are essential for molar morphogenesis and cytodifferentiation. PMID:11732842

  9. Insights into female germ cell biology: from in vivo development to in vitro derivations

    PubMed Central

    Jung, Dajung; Kee, Kehkooi

    2015-01-01

    Understanding the mechanisms of human germ cell biology is important for developing infertility treatments. However, little is known about the mechanisms that regulate human gametogenesis due to the difficulties in collecting samples, especially germ cells during fetal development. In contrast to the mitotic arrest of spermatogonia stem cells in the fetal testis, female germ cells proceed into meiosis and began folliculogenesis in fetal ovaries. Regulations of these developmental events, including the initiation of meiosis and the endowment of primordial follicles, remain an enigma. Studying the molecular mechanisms of female germ cell biology in the human ovary has been mostly limited to spatiotemporal characterizations of genes or proteins. Recent efforts in utilizing in vitro differentiation system of stem cells to derive germ cells have allowed researchers to begin studying molecular mechanisms during human germ cell development. Meanwhile, the possibility of isolating female germline stem cells in adult ovaries also excites researchers and generates many debates. This review will mainly focus on presenting and discussing recent in vivo and in vitro studies on female germ cell biology in human. The topics will highlight the progress made in understanding the three main stages of germ cell developments: namely, primordial germ cell formation, meiotic initiation, and folliculogenesis. PMID:25652637

  10. Stem Cell Property of Postmigratory Cranial Neural Crest Cells and Their Utility in Alveolar Bone Regeneration and Tooth Development

    PubMed Central

    Chung, Il-Hyuk; Yamaza, Takayoshi; Zhao, Hu; Choung, Pill-Hoon; Shi, Songtao; Chai, Yang

    2010-01-01

    The vertebrate neural crest is a multipotent cell population that gives rise to a variety of different cell types. We have discovered that postmigratory cranial neural crest cells (CNCCs) maintain mesenchymal stem cell characteristics and show potential utility for the regeneration of craniofacial structures. We are able to induce the osteogenic differentiation of postmigratory CNCCs, and this differentiation is regulated by bone morphogenetic protein (BMP) and transforming growth factor-β signaling pathways. After transplantation into a host animal, postmigratory CNCCs form bone matrix. CNCC-formed bones are distinct from bones regenerated by bone marrow mesenchymal stem cells. In addition, CNCCs support tooth germ survival via BMP signaling in our CNCC-tooth germ cotransplantation system. Thus, we conclude that postmigratory CNCCs preserve stem cell features, contribute to craniofacial bone formation, and play a fundamental role in supporting tooth organ development. These findings reveal a novel function for postmigratory CNCCs in organ development, and demonstrate the utility of these CNCCs in regenerating craniofacial structures. PMID:19350689

  11. The development of complex tooth shape in reptiles

    PubMed Central

    Zahradnicek, Oldrich; Buchtova, Marcela; Dosedelova, Hana; Tucker, Abigail S.

    2014-01-01

    Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid, and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus, and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development. PMID:24611053

  12. The development of complex tooth shape in reptiles.

    PubMed

    Zahradnicek, Oldrich; Buchtova, Marcela; Dosedelova, Hana; Tucker, Abigail S

    2014-01-01

    Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid, and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus, and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development. PMID:24611053

  13. nanos function is essential for development and regeneration of planarian germ cells.

    PubMed

    Wang, Yuying; Zayas, Ricardo M; Guo, Tingxia; Newmark, Phillip A

    2007-04-01

    Germ cells are required for the successful propagation of sexually reproducing species. Understanding the mechanisms by which these cells are specified and how their totipotency is established and maintained has important biomedical and evolutionary implications. Freshwater planarians serve as fascinating models for studying these questions. They can regenerate germ cells from fragments of adult tissues that lack reproductive structures, suggesting that inductive signaling is involved in planarian germ cell specification. To study the development and regeneration of planarian germ cells, we have functionally characterized an ortholog of nanos, a gene required for germ cell development in diverse organisms, from Schmidtea mediterranea. In the hermaphroditic strain of this species, Smed-nanos mRNA is detected in developing, regenerating, and mature ovaries and testes. However, it is not detected in the vast majority of newly hatched planarians or in small tissue fragments that will ultimately regenerate germ cells, consistent with an epigenetic origin of germ cells. We show that Smed-nanos RNA interference (RNAi) results in failure to develop, regenerate, or maintain gonads in sexual planarians. Unexpectedly, Smed-nanos mRNA is also detected in presumptive testes primordia of asexual individuals that reproduce strictly by fission. These presumptive germ cells are lost after Smed-nanos RNAi, suggesting that asexual planarians specify germ cells, but their differentiation is blocked downstream of Smed-nanos function. Our results reveal a conserved function of nanos in germ cell development in planarians and suggest that these animals will serve as useful models for dissecting the molecular basis of epigenetic germ cell specification. PMID:17376870

  14. Sox2 contributes to tooth development via Wnt signaling.

    PubMed

    Lee, Min-Jung; Kim, Eun-Jung; Otsu, Keishi; Harada, Hidemitsu; Jung, Han-Sung

    2016-07-01

    The transcription factor Sox2 is a stem cell marker that dictates cell lineage. It has been shown to mark the epithelial stem cells of the continuously growing mouse incisors. Sox2 also interferes with Wnt signaling by binding to β-catenin, a central mediator of the Wnt pathway. We show that these functions of Sox2 are essential for mouse molar development. Sox2 has previously been shown to play a role in the formation of new teeth from the existing dental epithelium. To assess Sox2 function related to cell migration within a tooth, we monitored cell movement by using a DiI system and observed that DiI moves from molar 1 to molar 2 during tooth development. However, upon temporal knockdown of Sox2, DiI remains in the molar 1 region. This study also provides novel insights into the role of Sox2 and the important validation of Sox2 as a potent target in Wnt signaling during tooth development. Our data reveal that the degradation of Wnt signaling caused by the knockdown of Sox2 results in a lack of cell migration during tooth development. PMID:26846112

  15. Whole Tooth Regeneration as a Future Dental Treatment.

    PubMed

    Oshima, Masamitsu; Tsuji, Takashi

    2015-01-01

    Dental problems caused by dental caries, periodontal disease and tooth injury compromise the oral and general health issues. Current advances for the development of regenerative therapy have been influenced by our understanding of embryonic development, stem cell biology, and tissue engineering technology. Tooth regenerative therapy for tooth tissue repair and whole tooth replacement is currently expected a novel therapeutic concept with the full recovery of tooth physiological functions. Dental stem cells and cell-activating cytokines are thought to be candidate approach for tooth tissue regeneration because they have the potential to differentiate into tooth tissues in vitro and in vivo. Whole tooth replacement therapy is considered to be an attractive concept for next generation regenerative therapy as a form of bioengineered organ replacement. For realization of whole tooth regeneration, we have developed a novel three-dimensional cell manipulation method designated the "organ germ method". This method involves compartmentalisation of epithelial and mesenchymal cells at a high cell density to mimic multicellular assembly conditions and epithelial-mesenchymal interactions in organogenesis. The bioengineered tooth germ generates a structurally correct tooth in vitro, and erupted successfully with correct tooth structure when transplanted into the oral cavity. We have ectopically generated a bioengineered tooth unit composed of a mature tooth, periodontal ligament and alveolar bone, and that tooth unit was engrafted into an adult jawbone through bone integration. Bioengineered teeth were also able to perform physiological tooth functions such as mastication, periodontal ligament function and response to noxious stimuli. In this review, we describe recent findings and technologies underpinning whole tooth regenerative therapy. PMID:26545754

  16. An Nfic-hedgehog signaling cascade regulates tooth root development.

    PubMed

    Liu, Yang; Feng, Jifan; Li, Jingyuan; Zhao, Hu; Ho, Thach-Vu; Chai, Yang

    2015-10-01

    Coordination between the Hertwig's epithelial root sheath (HERS) and apical papilla (AP) is crucial for proper tooth root development. The hedgehog (Hh) signaling pathway and Nfic are both involved in tooth root development; however, their relationship has yet to be elucidated. Here, we establish a timecourse of mouse molar root development by histological staining of sections, and we demonstrate that Hh signaling is active before and during root development in the AP and HERS using Gli1 reporter mice. The proper pattern of Hh signaling activity in the AP is crucial for the proliferation of dental mesenchymal cells, because either inhibition with Hh inhibitors or constitutive activation of Hh signaling activity in transgenic mice leads to decreased proliferation in the AP and shorter roots. Moreover, Hh activity is elevated in Nfic(-/-) mice, a root defect model, whereas RNA sequencing and in situ hybridization show that the Hh attenuator Hhip is downregulated. ChIP and RNAscope analyses suggest that Nfic binds to the promoter region of Hhip. Treatment of Nfic(-/-) mice with Hh inhibitor partially restores cell proliferation, AP growth and root development. Taken together, our results demonstrate that an Nfic-Hhip-Hh signaling pathway is crucial for apical papilla growth and proper root formation. This discovery provides insight into the molecular mechanisms regulating tooth root development. PMID:26293299

  17. Control over the morphology and segregation of Zebrafish germ cell granules during embryonic development

    PubMed Central

    Strasser, Markus J; Mackenzie, Natalia C; Dumstrei, Karin; Nakkrasae, La-Iad; Stebler, Jürg; Raz, Erez

    2008-01-01

    Background Zebrafish germ cells contain granular-like structures, organized around the cell nucleus. These structures share common features with polar granules in Drosophila, germinal granules in Xenopus and chromatoid bodies in mice germ cells, such as the localization of the zebrafish Vasa, Piwi and Nanos proteins, among others. Little is known about the structure of these granules as well as their segregation in mitosis during early germ-cell development. Results Using transgenic fish expressing a fluorescently labeled novel component of Zebrafish germ cell granules termed Granulito, we followed the morphology and distribution of the granules. We show that whereas these granules initially exhibit a wide size variation, by the end of the first day of development they become a homogeneous population of medium size granules. We investigated this resizing event and demonstrated the role of microtubules and the minus-end microtubule dependent motor protein Dynein in the process. Last, we show that the function of the germ cell granule resident protein the Tudor domain containing protein-7 (Tdrd7) is required for determination of granule morphology and number. Conclusion Our results suggest that Zebrafish germ cell granules undergo a transformation process, which involves germ cell specific proteins as well as the microtubular network. PMID:18507824

  18. The lateral enamel lamina--component of tooth primordia in selected mammalian species.

    PubMed

    Witter, K; Matulová, P; Mísek, I

    2002-01-01

    The lateral enamel lamina (LEL) is a part of the enamel organ, which is probably not involved in tooth formation. It represents, besides the "stalk" of the tooth primordium, a second interconnection between enamel organ and oral epithelium or vestibular lamina. We detected the LEL in the sheep (Ovis aries), the dolphin (Stenella attenuata), and the vole (Microtus agrestis) by light microscopy and computer-aided three-dimensional reconstruction. The LEL could be found in cap to bell stage tooth primordia, most clearly in slowly developing tooth germs. LEL-like structures have been furthermore described or depicted in tooth germs of the mouse, the elk (Alces alces), the dugong (Dugong dugong), the elephant (Loxodonta africana), and the human. Probably it is a part of all mammalian tooth primordia that undergoes regression during morphogenesis of the enamel organ. As a reducing structure, it should be considered in studies of tooth development. PMID:12494916

  19. Germ cells of the centipede Strigamia maritima are specified early in embryonic development.

    PubMed

    Green, Jack E; Akam, Michael

    2014-08-15

    We provide the first systematic description of germ cell development with molecular markers in a myriapod, the centipede Strigamia maritima. By examining the expression of Strigamia vasa and nanos orthologues, we find that the primordial germ cells are specified from at least the blastoderm stage. This is a much earlier embryonic stage than previously described for centipedes, or any other member of the Myriapoda. Using these genes as markers, and taking advantage of the developmental synchrony of Strigamia embryos within single clutches, we are able to track the development of the germ cells throughout embryogenesis. We find that the germ cells accumulate at the blastopore; that the cells do not internalize through the hindgut, but rather through the closing blastopore; and that the cells undergo a long-range migration to the embryonic gonad. This is the first evidence for primordial germ cells displaying these behaviours in any myriapod. The myriapods are a phylogenetically important group in the arthropod radiation for which relatively little developmental data is currently available. Our study provides valuable comparative data that complements the growing number of studies in insects, crustaceans and chelicerates, and is important for the correct reconstruction of ancestral states and a fuller understanding of how germ cell development has evolved in different arthropod lineages. PMID:24930702

  20. Primary Cilia Integrate Hedgehog and Wnt Signaling during Tooth Development

    PubMed Central

    Liu, B.; Chen, S.; Cheng, D.; Jing, W.; Helms, J.A.

    2014-01-01

    Many ciliopathies have clinical features that include tooth malformations but how these defects come about is not clear. Here we show that genetic deletion of the motor protein Kif3a in dental mesenchyme results in an arrest in odontogenesis. Incisors are completely missing, and molars are enlarged in Wnt1Cre+Kif3afl/fl embryos. Although amelogenesis and dentinogenesis initiate in the molar tooth bud, both processes terminate prematurely. We demonstrate that loss of Kif3a in dental mesenchyme results in loss of Hedgehog signaling and gain of Wnt signaling in this same tissue. The defective dental mesenchyme then aberrantly signals to the dental epithelia, which prompts an up-regulation in the Hedgehog and Wnt responses in the epithelia and leads to multiple attempts at invagination and an expanded enamel organ. Thus, the primary cilium integrates Hedgehog and Wnt signaling between dental epithelia and mesenchyme, and this cilia-dependent integration is required for proper tooth development. PMID:24659776

  1. Expression of dynamin II in odontoblast during mouse tooth development.

    PubMed

    Oh, Jong-Hwa; Choi, Baik-Dong; Park, Jin-Ju; Jeong, Soon-Jeong; Kim, Jin-Soo; Kim, Jae-Duk; Lim, Do-Seon; Kim, Byung-Hoon; Cho, Yong-Ick; Jeong, Moon-Jin

    2011-08-01

    Odontoblasts secrete a collagen-based matrix and release numerous membrane-bound matrix vesicles, which are involved in dentin formation during tooth development. Dynamin II is a GTPase protein that contributes a variety of vesicular budding events, such as endocytotic membrane fission, caveolae internalization and protein trafficking in the Golgi apparatus. However, the expression and function of dynamin II in odontoblasts has not been reported. Therefore, this study examined the expression and possible role of dynamin II in odontoblasts during tooth development and mineralization. The levels of mRNA and protein expression in MDPC23 cells were significantly high at the early stages of differentiation and then decreased gradually thereafter. Immunohistochemistry showed that dynamin II was not expressed near the region of the odontoblasts at embryonic day 17 (E17) and E21. However, dynamin II was expressed strongly in the odontoblast layer at postnatal day 1 (PN1) and decreased gradually at PN3 and PN5. In addition, at PN15 in the functional stage, the dynamin II protein was also expressed in the odontoblast process as well as adjacent to the nuclear region. In conclusion, dynamin II may be involved in the transport of vesicles containing collageneous and non-collageneous proteins for dentin formation in odontoblast, suggesting that it is a good nanomolecule as a candidate to regulate the secretion of collagen on the bone and other nano material. PMID:22103132

  2. Development of interspecies testicular germ-cell transplantation in flatfish.

    PubMed

    Pacchiarini, Tiziana; Sarasquete, Carmen; Cabrita, Elsa

    2014-06-01

    Interspecific testicular germ cell (TGC) transplantation was investigated in two commercial flatfish species. Testes from donor species (Senegalese sole) were evaluated using classical histological techniques (haematoxylin-eosin staining and haematoxylin-light green-orange G-acid fuchsine staining), in situ hybridisation and immunohistochemical analysis. Both Ssvasa1-2 mRNAs and SsVasa protein allowed the characterisation of TGCs, confirming the usefulness of the vasa gene in the detection of Senegalese sole TGCs. Xenogenic transplants were carried out using TGCs from one-year-old Senegalese sole into turbot larvae. Propidium iodide-SYBR-14 and 4',6'-diamidino-2-phenylindole (DAPI) staining showed that 87.98% of the extracted testicular cells were viable for microinjection and that 15.63% of the total recovered cells were spermatogonia. The vasa gene was characterised in turbot recipients using cDNA cloning. Smvasa mRNA was confirmed as a germ cell-specific molecular marker in this species. Smvasa expression analysis during turbot ontogeny was carried out before Senegalese sole TGC transplants into turbot larvae. Turbot larvae at 18 days after hatching (DAH) proved to be susceptible to manipulation procedures. High survival rates (83.75±15.90-100%) were obtained for turbot larvae at 27, 34 and 42 DAH. These data highlight the huge potential of this species for transplantation studies. Quantitative PCR was employed to detect Senegalese sole vasa mRNAs (Ssvasa1-2) in the recipient turbot larvae. The Ssvasa mRNAs showed a significant increase in relative expression in 42-DAH microinjected larvae three weeks after treatment, showing the proliferation of Senegalese sole spermatogonia in transplanted turbot larvae. PMID:23735683

  3. Germ cell development in the postnatal testis: the key to prevent malignancy in cryptorchidism?

    PubMed Central

    Hutson, John M.; Li, Ruili; Southwell, Bridget R.; Petersen, Bodil L.; Thorup, Jorgen; Cortes, Dina

    2013-01-01

    To permit normal postnatal germ cell development, the mammalian testis undergoes a complex, multi-staged process of descent to the scrotum. Failure of any part of this process leads to congenital cryptorchidism, wherein the malpositioned testis finds itself at the wrong temperature after birth, which leads to secondary germ cell loss and later infertility and risk of cancer. Recent studies suggest that neonatal gonocytes transform into the putative spermatogenic stem cells between 3 and 9 months, and this initial postnatal step is deranged in cryptorchid testes. In addition, it is thought the abnormality high temperature may also impair apoptosis of remaining gonocytes, allowing some to persist to become the possible source of carcinoma in situ and malignancy after puberty. The biology of postnatal germ cell development is of intense interest, as it is likely to be the key to the optimal timing for orchidopexy. PMID:23316184

  4. Sufficient Numbers of Early Germ Cells Are Essential for Female Sex Development in Zebrafish

    PubMed Central

    Dai, Xiangyan; Jin, Xia; Chen, Xiaowen; He, Jiangyan; Yin, Zhan

    2015-01-01

    The sex determination for zebrafish is controlled by a combination of genetic and environmental factors. The determination of sex in zebrafish has been suggested to rely on a mechanism that is affected by germ cell-derived signals. To begin our current study, a simplified and efficient germ cell-specific promoter of the dead end (dnd) gene was identified. Utilizing the metrodinazole (MTZ)/ bacterial nitroreductase (NTR) system for inducible germ cell ablation, several stable Tg (dnd:NTR-EGFP-3'UTR) and Tg (dnd:NTR-EGFP+3'UTR) zebrafish lines were then generated with the identified promoter. A thorough comparison of the expression patterns and tissue distributions of endogenous dnd and ntr-egfp transcripts in vivo revealed that the identified 2032-bp zebrafish dnd promoter can recapitulate dnd expression faithfully in stable transgenic zebrafish. The correlation between the levels of the germ cell-derived signals and requirement for maintaining the female fate has been also explored with different durations of the MTZ treatments. Our results revealed the decreasing ratios of female presented in the treated transgenic group are fairly associated with the reducing levels of the early germ cell-derived signals. After the juvenile transgenic fish treated with 5 mM MTZ for 20 days, all MTZ-treated transgenic fish exclusively developed into males with subfertilities. Taken together, our results identified here a simplified and efficient dnd promoter, and provide clear evidence indicating that it was not the presence but the sufficiency of signals derived from germ cells that is essential for female sex development in zebrafish. Our model also provides a unique system for sex control in zebrafish studies. PMID:25679390

  5. GermlncRNA: a unique catalogue of long non-coding RNAs and associated regulations in male germ cell development.

    PubMed

    Luk, Alfred Chun-Shui; Gao, Huayan; Xiao, Sizhe; Liao, Jinyue; Wang, Daxi; Tu, Jiajie; Rennert, Owen M; Chan, Wai-Yee; Lee, Tin-Lap

    2015-01-01

    Spermatogenic failure is a major cause of male infertility, which affects millions of couples worldwide. Recent discovery of long non-coding RNAs (lncRNAs) as critical regulators in normal and disease development provides new clues for delineating the molecular regulation in male germ cell development. However, few functional lncRNAs have been characterized to date. A major limitation in studying lncRNA in male germ cell development is the absence of germ cell-specific lncRNA annotation. Current lncRNA annotations are assembled by transcriptome data from heterogeneous tissue sources; specific germ cell transcript information of various developmental stages is therefore under-represented, which may lead to biased prediction or fail to identity important germ cell-specific lncRNAs. GermlncRNA provides the first comprehensive web-based and open-access lncRNA catalogue for three key male germ cell stages, including type A spermatogonia, pachytene spermatocytes and round spermatids. This information has been developed by integrating male germ transcriptome resources derived from RNA-Seq, tiling microarray and GermSAGE. Characterizations on lncRNA-associated regulatory features, potential coding gene and microRNA targets are also provided. Search results from GermlncRNA can be exported to Galaxy for downstream analysis or downloaded locally. Taken together, GermlncRNA offers a new avenue to better understand the role of lncRNAs and associated targets during spermatogenesis. Database URL: http://germlncrna.cbiit.cuhk.edu.hk/ PMID:25982314

  6. GermlncRNA: a unique catalogue of long non-coding RNAs and associated regulations in male germ cell development

    PubMed Central

    Luk, Alfred Chun-Shui; Gao, Huayan; Xiao, Sizhe; Liao, Jinyue; Wang, Daxi; Tu, Jiajie; Rennert, Owen M.; Chan, Wai-Yee; Lee, Tin-Lap

    2015-01-01

    Spermatogenic failure is a major cause of male infertility, which affects millions of couples worldwide. Recent discovery of long non-coding RNAs (lncRNAs) as critical regulators in normal and disease development provides new clues for delineating the molecular regulation in male germ cell development. However, few functional lncRNAs have been characterized to date. A major limitation in studying lncRNA in male germ cell development is the absence of germ cell-specific lncRNA annotation. Current lncRNA annotations are assembled by transcriptome data from heterogeneous tissue sources; specific germ cell transcript information of various developmental stages is therefore under-represented, which may lead to biased prediction or fail to identity important germ cell-specific lncRNAs. GermlncRNA provides the first comprehensive web-based and open-access lncRNA catalogue for three key male germ cell stages, including type A spermatogonia, pachytene spermatocytes and round spermatids. This information has been developed by integrating male germ transcriptome resources derived from RNA-Seq, tiling microarray and GermSAGE. Characterizations on lncRNA-associated regulatory features, potential coding gene and microRNA targets are also provided. Search results from GermlncRNA can be exported to Galaxy for downstream analysis or downloaded locally. Taken together, GermlncRNA offers a new avenue to better understand the role of lncRNAs and associated targets during spermatogenesis. Database URL: http://germlncrna.cbiit.cuhk.edu.hk/ PMID:25982314

  7. Identification of Grandchildless Loci Whose Products Are Required for Normal Germ-Line Development in the Nematode Caenorhabditis Elegans

    PubMed Central

    Capowski, E. E.; Martin, P.; Garvin, C.; Strome, S.

    1991-01-01

    To identify genes that encode maternal components required for development of the germ line in the nematode Caenorhabditis elegans, we have screened for mutations that confer a maternal-effect sterile or ``grandchildless'' phenotype: homozygous mutant hermaphrodites produced by heterozygous mothers are themselves fertile, but produce sterile progeny. Our screens have identified six loci, defined by 21 mutations. This paper presents genetic and phenotypic characterization of four of the loci. The majority of mutations, those in mes-2, mes-3 and mes-4, affect postembryonic germ-line development; the progeny of mutant mothers undergo apparently normal embryogenesis but develop into agametic adults with 10-1000-fold reductions in number of germ cells. In contrast, mutations in mes-1 cause defects in cytoplasmic partitioning during embryogenesis, and the resulting larvae lack germ-line progenitor cells. Mutations in all of the mes loci primarily affect the germ line, and none disrupt the structural integrity of germ granules. This is in contrast to grandchildless mutations in Drosophila melanogaster, all of which disrupt germ granules and affect abdominal as well as germ-line development. PMID:1783292

  8. DAZL limits pluripotency, differentiation, and apoptosis in developing primordial germ cells.

    PubMed

    Chen, Hsu-Hsin; Welling, Maaike; Bloch, Donald B; Muñoz, Javier; Mientjes, Edwin; Chen, Xinjie; Tramp, Cody; Wu, Jie; Yabuuchi, Akiko; Chou, Yu-Fen; Buecker, Christa; Krainer, Adrian; Willemsen, Rob; Heck, Albert J; Geijsen, Niels

    2014-11-11

    The scarcity of primordial germ cells (PGCs) in the developing mammalian embryo hampers robust biochemical analysis of the processes that underlie early germ cell formation. Here, we demonstrate that DAZL, a germ cell-specific RNA binding protein, is a robust PGC marker during in vitro germ cell development. Using Dazl-GFP reporter ESCs, we demonstrate that DAZL plays a central role in a large mRNA/protein interactive network that blocks the translation of core pluripotency factors, including Sox2 and Sall4, as well as of Suz12, a polycomb family member required for differentiation of pluripotent cells. Thus, DAZL limits both pluripotency and somatic differentiation in nascent PGCs. In addition, we observed that DAZL associates with mRNAs of key Caspases and similarly inhibits their translation. This elegant fail-safe mechanism ensures that, whereas loss of DAZL results in prolonged expression of pluripotency factors, teratoma formation is avoided due to the concomitant activation of the apoptotic cascade. PMID:25418731

  9. Beta-Catenin and Plakoglobin Expression during Zebrafish Tooth Development and Replacement

    PubMed Central

    Verstraeten, Barbara; van Hengel, Jolanda; Huysseune, Ann

    2016-01-01

    We analyzed the protein distribution of two cadherin-associated molecules, plakoglobin and β-catenin, during the different stages of tooth development and tooth replacement in zebrafish. Plakoglobin was detected at the plasma membrane already at the onset of tooth development in the epithelial cells of the tooth. This pattern remained unaltered during further tooth development. The mesenchymal cells only showed plakoglobin from cytodifferentiation onwards. Plakoglobin 1a morpholino-injected embryos showed normal tooth development with proper initiation and differentiation. Although plakoglobin is clearly present during normal odontogenesis, the loss of plakoglobin 1a does not influence tooth development. β-catenin was found at the cell borders of all cells of the successional lamina but also in the nuclei of surrounding mesenchymal cells. Only membranous, not nuclear, β-catenin, was found during morphogenesis stage. However, during cytodifferentiation stage, both nuclear and membrane-bound β-catenin was detected in the layers of the enamel organ as well as in the differentiating odontoblasts. Nuclear β-catenin is an indication of an activated Wnt pathway, therefore suggesting a possible role for Wnt signalling during zebrafish tooth development and replacement. PMID:26938059

  10. Beta-Catenin and Plakoglobin Expression during Zebrafish Tooth Development and Replacement.

    PubMed

    Verstraeten, Barbara; van Hengel, Jolanda; Huysseune, Ann

    2016-01-01

    We analyzed the protein distribution of two cadherin-associated molecules, plakoglobin and β-catenin, during the different stages of tooth development and tooth replacement in zebrafish. Plakoglobin was detected at the plasma membrane already at the onset of tooth development in the epithelial cells of the tooth. This pattern remained unaltered during further tooth development. The mesenchymal cells only showed plakoglobin from cytodifferentiation onwards. Plakoglobin 1a morpholino-injected embryos showed normal tooth development with proper initiation and differentiation. Although plakoglobin is clearly present during normal odontogenesis, the loss of plakoglobin 1a does not influence tooth development. β-catenin was found at the cell borders of all cells of the successional lamina but also in the nuclei of surrounding mesenchymal cells. Only membranous, not nuclear, β-catenin, was found during morphogenesis stage. However, during cytodifferentiation stage, both nuclear and membrane-bound β-catenin was detected in the layers of the enamel organ as well as in the differentiating odontoblasts. Nuclear β-catenin is an indication of an activated Wnt pathway, therefore suggesting a possible role for Wnt signalling during zebrafish tooth development and replacement. PMID:26938059

  11. Germ line development in the grasshopper Schistocerca gregaria: vasa as a marker.

    PubMed

    Chang, Chun-che; Dearden, Peter; Akam, Michael

    2002-12-01

    Vasa is a widely conserved germline marker, both in vertebrates and invertebrates. We identify a vasa orthologue, Sgvasa, and use it to study germline development in the grasshopper Schistocerca gregaria, a species in which no germ plasm has been identified. In adults, Sgvasa is specifically expressed in the ovary and testis. It is expressed at high levels during early oogenesis, but no detectable vasa RNA and little Vasa protein are present in mature unlaid eggs. None appears to be localized to any defined region of the egg cortex, suggesting that germline specification may not depend on maternal germ plasm expressing vasa. Vasa protein is expressed in most cleavage energids as they reach the egg surface and persists at high levels in most cells aggregating to form the embryonic primordium. However, after gastrulation, Vasa protein persists only in extraembryonic membranes and in cells at the outer margin of the late heart-stage embryo. In the embryo, it then become restricted to cells at the dorsal margin of the forming abdomen. In older embryos, these Vasa-positive cells move toward the midline; Vasa protein accumulates asymmetrically in their cytoplasm, a pattern closely resembling that of germ cells in late embryonic gonads. Thus, we suggest that the Vasa-stained cells in the abdominal margin are germ cells, as proposed by Nelson (1934), and not cardioblasts, as has been proposed by others. PMID:12453463

  12. Gene Expression Analysis during Conidial Germ Tube and Appressorium Development in Colletotrichum trifolii

    PubMed Central

    Buhr, T. L.; Dickman, M. B.

    1997-01-01

    Preinfection development in Colletotrichum spp. exhibits three morphologies (conidia, germ tubes, and appressoria) and is directed by a complex interplay of environmental signals. Germ tube morphogenesis for Colletotrichum trifolii and the related fungus Colletotrichum gloeosporioides f. sp. aeschynomene was shown to be partially dependent on a balance between self-germination inhibitors and environmental nutrients or cutin. The degree of responsiveness to these environmental signals was strikingly different between the two fungal species. A solid contact surface stimulated germ tube morphogenesis and was the only apparent requirement for appressorium morphogenesis in both fungi. A population of C. trifolii conidia was incubated on a solid surface in the presence of cutin to stimulate nearly synchronous preinfection morphogenesis for gene expression analysis. RNA analysis of signal-transducing genes from C. trifolii, including genes for a serine-threonine kinase (TB3), calmodulin, and protein kinase C, showed that maximum transcription of all three genes occurred in conidia prior to or during germ tube morphogenesis. Transcription of melanin biosynthetic genes THR1 and SCD1 (Y. Kubo, Y. Takano, and I. Furusawa, Colletotrichum Newsl. II:5-10, 1996; N. S. Perpetua, Y. Kubo, N. Yasuda, Y. Takano, and I. Furusawa, Mol. Plant-Microbe Interact. 9:323-329, 1996) was highest prior to and during appressorium morphogenesis. PMID:16535630

  13. DDX4 (VASA) is conserved in germ cell development in marsupials and monotremes.

    PubMed

    Hickford, Danielle E; Frankenberg, Stephen; Pask, Andrew J; Shaw, Geoff; Renfree, Marilyn B

    2011-10-01

    DDX4 (VASA) is an RNA helicase expressed in the germ cells of all animals. To gain greater insight into the role of this gene in mammalian germ cell development, we characterized DDX4 in both a marsupial (the tammar wallaby) and a monotreme (the platypus). DDX4 is highly conserved between eutherian, marsupial, and monotreme mammals. DDX4 protein is absent from tammar fetal germ cells but is present from Day 1 postpartum in both sexes. The distribution of DDX4 protein during oogenesis and spermatogenesis in the tammar is similar to eutherians. Female tammar germ cells contain DDX4 protein throughout all stages of postnatal oogenesis. In males, DDX4 is in gonocytes, and during spermatogenesis it is present in spermatocytes and round spermatids. A similar distribution of DDX4 occurs in the platypus during spermatogenesis. There are several DDX4 isoforms in the tammar, resulting from both pre- and posttranslational modifications. DDX4 in marsupials and monotremes has multiple splice variants and polyadenylation motifs. Using in silico analyses of genomic databases, we found that these previously unreported splice variants also occur in eutherians. In addition, several elements implicated in the control of Ddx4 expression in the mouse, including RGG (arginine-glycine-glycine) and dimethylation of arginine motifs and CpG islands within the Ddx4 promoter, are also highly conserved. Collectively these data suggest that DDX4 is essential for the regulation of germ cell proliferation and differentiation across all three extant mammalian groups-eutherians, marsupials, and monotremes. PMID:21653890

  14. Germline development in amniotes: A paradigm shift in primordial germ cell specification.

    PubMed

    Bertocchini, Federica; Chuva de Sousa Lopes, Susana M

    2016-08-01

    In the field of germline development in amniote vertebrates, primordial germ cell (PGC) specification in birds and reptiles remains controversial. Avians are believed to adopt a predetermination or maternal specification mode of PGC formation, contrary to an inductive mode employed by mammals and, supposedly, reptiles. Here, we revisit and review some key aspects of PGC development that channelled the current subdivision, and challenge the position of birds and reptiles as well as the 'binary' evolutionary model of PGC development in vertebrates. We propose an alternative view on PGC specification where germ plasm plays a role in laying the foundation for the formation of PGC precursors (pPGC), but not necessarily of PGCs. Moreover, inductive mechanisms may be necessary for the transition from pPGCs to PGCs. Within this framework, the implementation of data from birds and reptiles could provide new insights on the evolution of PGC specification in amniotes. PMID:27273724

  15. Photoreversible inhibition by ultraviolet light of germ line development in Smittia sp. (Chironomidae, Diptera)

    SciTech Connect

    von Brunn, A.; Kalthoff, K.

    1983-12-01

    Pole cell formation in embryos of the parthenogenetic midge, Smittia sp., can be delayed or inhibited by irradiation of the posterior egg pole with ultraviolet light (uv). This leaves the schedule of nuclear divisions and chromosome eliminations virtually unaffected. However, uv irradiation delays the precocious migration to the posterior pole of one nucleus, which normally becomes included in the first pole cell. This effect is photoreversible, i.e., mitigated by application of blue light after uv. Photoreversibility indicates that a nucleic acid component is involved as an effective target. During normal development of Smittia a number of chromosomes are eliminated during mitosis V, not only from somatic nuclei but also in the germ line. In the latter, this mitosis takes place during the first gonial division in the larva. After uv irradiation, the first pole cell nucleus has undergone supernumerary mitoses before pole cell formation and, as a result, is driven into mitosis V precociously as the pole cell divides. This is frequently associated with chromosome elimination from pole cells, which in turn is correlated with subsequent disappearance of already formed pole cells. Adults derived from embryos without pole cells do not form ovaries. Pole cell formation, pole cell preservation, and ovary development are separately inhibited by uv, and inhibition of each step is photoreversible. The results are discussed in the context of germ cell determination, protection against chromosome elimination, and the role of chromosomes limited to the germ line.

  16. Exome Sequencing of Bilateral Testicular Germ Cell Tumors Suggests Independent Development Lineages12

    PubMed Central

    Brabrand, Sigmund; Johannessen, Bjarne; Axcrona, Ulrika; Kraggerud, Sigrid M.; Berg, Kaja G.; Bakken, Anne C.; Bruun, Jarle; Fosså, Sophie D.; Lothe, Ragnhild A.; Lehne, Gustav; Skotheim, Rolf I.

    2015-01-01

    Intratubular germ cell neoplasia, the precursor of testicular germ cell tumors (TGCTs), is hypothesized to arise during embryogenesis from developmentally arrested primordial germ cells (PGCs) or gonocytes. In early embryonal life, the PGCs migrate from the yolk sac to the dorsal body wall where the cell population separates before colonizing the genital ridges. However, whether the malignant transformation takes place before or after this separation is controversial. We have explored the somatic exome-wide mutational spectra of bilateral TGCT to provide novel insight into the in utero critical time frame of malignant transformation and TGCT pathogenesis. Exome sequencing was performed in five patients with bilateral TGCT (eight tumors), of these three patients in whom both tumors were available (six tumors) and two patients each with only one available tumor (two tumors). Selected loci were explored by Sanger sequencing in 71 patients with bilateral TGCT. From the exome-wide mutational spectra, no identical mutations in any of the three bilateral tumor pairs were identified. Exome sequencing of all eight tumors revealed 87 somatic non-synonymous mutations (median 10 per tumor; range 5-21), some in already known cancer genes such as CIITA, NEB, platelet-derived growth factor receptor α (PDGFRA), and WHSC1. SUPT6H was found recurrently mutated in two tumors. We suggest independent development lineages of bilateral TGCT. Thus, malignant transformation into intratubular germ cell neoplasia is likely to occur after the migration of PGCs. We reveal possible drivers of TGCT pathogenesis, such as mutated PDGFRA, potentially with therapeutic implications for TGCT patients. PMID:25748235

  17. Exome sequencing of bilateral testicular germ cell tumors suggests independent development lineages.

    PubMed

    Brabrand, Sigmund; Johannessen, Bjarne; Axcrona, Ulrika; Kraggerud, Sigrid M; Berg, Kaja G; Bakken, Anne C; Bruun, Jarle; Fosså, Sophie D; Lothe, Ragnhild A; Lehne, Gustav; Skotheim, Rolf I

    2015-02-01

    Intratubular germ cell neoplasia, the precursor of testicular germ cell tumors (TGCTs), is hypothesized to arise during embryogenesis from developmentally arrested primordial germ cells (PGCs) or gonocytes. In early embryonal life, the PGCs migrate from the yolk sac to the dorsal body wall where the cell population separates before colonizing the genital ridges. However, whether the malignant transformation takes place before or after this separation is controversial. We have explored the somatic exome-wide mutational spectra of bilateral TGCT to provide novel insight into the in utero critical time frame of malignant transformation and TGCT pathogenesis. Exome sequencing was performed in five patients with bilateral TGCT (eight tumors), of these three patients in whom both tumors were available (six tumors) and two patients each with only one available tumor (two tumors). Selected loci were explored by Sanger sequencing in 71 patients with bilateral TGCT. From the exome-wide mutational spectra, no identical mutations in any of the three bilateral tumor pairs were identified. Exome sequencing of all eight tumors revealed 87 somatic non-synonymous mutations (median 10 per tumor; range 5-21), some in already known cancer genes such as CIITA, NEB, platelet-derived growth factor receptor α (PDGFRA), and WHSC1. SUPT6H was found recurrently mutated in two tumors. We suggest independent development lineages of bilateral TGCT. Thus, malignant transformation into intratubular germ cell neoplasia is likely to occur after the migration of PGCs. We reveal possible drivers of TGCT pathogenesis, such as mutated PDGFRA, potentially with therapeutic implications for TGCT patients. PMID:25748235

  18. A simple rule governs the evolution and development of hominin tooth size.

    PubMed

    Evans, Alistair R; Daly, E Susanne; Catlett, Kierstin K; Paul, Kathleen S; King, Stephen J; Skinner, Matthew M; Nesse, Hans P; Hublin, Jean-Jacques; Townsend, Grant C; Schwartz, Gary T; Jernvall, Jukka

    2016-02-25

    The variation in molar tooth size in humans and our closest relatives (hominins) has strongly influenced our view of human evolution. The reduction in overall size and disproportionate decrease in third molar size have been noted for over a century, and have been attributed to reduced selection for large dentitions owing to changes in diet or the acquisition of cooking. The systematic pattern of size variation along the tooth row has been described as a 'morphogenetic gradient' in mammal, and more specifically hominin, teeth since Butler and Dahlberg. However, the underlying controls of tooth size have not been well understood, with hypotheses ranging from morphogenetic fields to the clone theory. In this study we address the following question: are there rules that govern how hominin tooth size evolves? Here we propose that the inhibitory cascade, an activator-inhibitor mechanism that affects relative tooth size in mammals, produces the default pattern of tooth sizes for all lower primary postcanine teeth (deciduous premolars and permanent molars) in hominins. This configuration is also equivalent to a morphogenetic gradient, finally pointing to a mechanism that can generate this gradient. The pattern of tooth size remains constant with absolute size in australopiths (including Ardipithecus, Australopithecus and Paranthropus). However, in species of Homo, including modern humans, there is a tight link between tooth proportions and absolute size such that a single developmental parameter can explain both the relative and absolute sizes of primary postcanine teeth. On the basis of the relationship of inhibitory cascade patterning with size, we can use the size at one tooth position to predict the sizes of the remaining four primary postcanine teeth in the row for hominins. Our study provides a development-based expectation to examine the evolution of the unique proportions of human teeth. PMID:26911784

  19. RNA Granules in Germ Cells

    PubMed Central

    Voronina, Ekaterina; Seydoux, Geraldine; Sassone-Corsi, Paolo; Nagamori, Ippei

    2011-01-01

    Germ granules” are cytoplasmic, nonmembrane-bound organelles unique to germline. Germ granules share components with the P bodies and stress granules of somatic cells, but also contain proteins and RNAs uniquely required for germ cell development. In this review, we focus on recent advances in our understanding of germ granule assembly, dynamics, and function. One hypothesis is that germ granules operate as hubs for the posttranscriptional control of gene expression, a function at the core of the germ cell differentiation program. PMID:21768607

  20. Molecular and biological aspects of early germ cell development in interspecies hybrids between chickens and pheasants.

    PubMed

    Kang, Seok Jin; Sohn, Sea Hwan; Kang, Kyung Soo; Lee, Hyung Chul; Lee, Seul Ki; Choi, Jin Won; Han, Jae Yong

    2011-03-01

    Interspecific hybrids provide insights into fundamental genetic principles, and may prove useful for biotechnological applications and as tools for the conservation of endangered species. In the present study, interspecies hybrids were generated between the Korean ring-necked pheasant (Phasianus colchicus) and the White Leghorn chicken (Gallus gallus domesticus). We determined whether these hybrids were good recipients for the production of germline chimeric birds. PCR-based species-specific amplification and karyotype analyses showed that the hybrids inherited genetic material from both parents. Evaluation of biological function indicated that the growth rates of hybrids during the exponential phase (body weight/week) were similar to those of the pheasant but not the chicken, and that the incubation period for hatching was significantly different from that of both parents. Primordial germ cells (PGCs) of hybrids reacted with a pheasant PGC-specific antibody and circulated normally in blood vessels. The peak time of hybrid PGC migration was equivalent to that of the pheasant. In late embryonic stages, germ cells were detected by the QCR1 antibody on 15 d male gonads and were normally localized in the seminiferous cords. We examined the migration ability and developmental localization of exogenous PGCs transferred into the blood vessels of 63 h hybrid embryos. Donor-derived PGCs reacted with a donor-specific antibody were detected on 7 d gonads and the seminiferous tubules of hatchlings. Therefore, germ cell transfer into developing embryos of an interspecies hybrid can be efficiently used for the conservation of threatened animals and endangered species, and many biotechnological applications. PMID:21111472

  1. Genome-wide association study reveals multiple loci associated with primary tooth development during infancy.

    PubMed

    Pillas, Demetris; Hoggart, Clive J; Evans, David M; O'Reilly, Paul F; Sipilä, Kirsi; Lähdesmäki, Raija; Millwood, Iona Y; Kaakinen, Marika; Netuveli, Gopalakrishnan; Blane, David; Charoen, Pimphen; Sovio, Ulla; Pouta, Anneli; Freimer, Nelson; Hartikainen, Anna-Liisa; Laitinen, Jaana; Vaara, Sarianna; Glaser, Beate; Crawford, Peter; Timpson, Nicholas J; Ring, Susan M; Deng, Guohong; Zhang, Weihua; McCarthy, Mark I; Deloukas, Panos; Peltonen, Leena; Elliott, Paul; Coin, Lachlan J M; Smith, George Davey; Jarvelin, Marjo-Riitta

    2010-02-01

    Tooth development is a highly heritable process which relates to other growth and developmental processes, and which interacts with the development of the entire craniofacial complex. Abnormalities of tooth development are common, with tooth agenesis being the most common developmental anomaly in humans. We performed a genome-wide association study of time to first tooth eruption and number of teeth at one year in 4,564 individuals from the 1966 Northern Finland Birth Cohort (NFBC1966) and 1,518 individuals from the Avon Longitudinal Study of Parents and Children (ALSPAC). We identified 5 loci at P<5x10(-8), and 5 with suggestive association (P<5x10(-6)). The loci included several genes with links to tooth and other organ development (KCNJ2, EDA, HOXB2, RAD51L1, IGF2BP1, HMGA2, MSRB3). Genes at four of the identified loci are implicated in the development of cancer. A variant within the HOXB gene cluster associated with occlusion defects requiring orthodontic treatment by age 31 years. PMID:20195514

  2. Functional Cues in the Development of Osseous Tooth Support in the Pig, Sus scrofa

    PubMed Central

    Popowics, T.; Yeh, K.; Rafferty, K.; Herring, S.

    2009-01-01

    Alveolar bone supports teeth during chewing through a ligamentous interface with tooth roots. Although tooth loads are presumed to direct the development and adaptation of these tissues, strain distribution in the alveolar bone at different stages of tooth eruption and periodontal development is unknown. This study investigates the biomechanical effects of tooth loading on developing alveolar bone as a tooth erupts into occlusion. Mandibular segments from miniature pigs, Sus scrofa, containing M1 either erupting or in functional occlusion, were loaded in compression. Simultaneous recordings were made from rosette strain gages affixed to the lingual alveolar bone and the M2 crypt. Overall, specimens with erupting M1's were more deformable than specimens with occluding M1's (mean stiffness of 246 vs. 944 Mpa, respectively, p=0.004). The major difference in alveolar strain between the two stages was in orientation. The vertically applied compressive loads were more directly reflected in the alveolar bone strains of erupting M1's, than those of occluding M1's, presumably because of the mediation of a more mature periodontal ligament (PDL) in the latter. The PDL interface between occluding teeth and alveolar bone is likely to stiffen the system, allowing transmission of occlusal loads. Alveolar strains may provide a stimulus for bone growth in the alveolar process and crest. PMID:19501361

  3. Telomeric repeat silencing in germ cells is essential for early development in Drosophila

    PubMed Central

    Morgunova, Valeriya; Akulenko, Natalia; Radion, Elizaveta; Olovnikov, Ivan; Abramov, Yuri; Olenina, Ludmila V.; Shpiz, Sergey; Kopytova, Daria V.; Georgieva, Sofia G.; Kalmykova, Alla

    2015-01-01

    The germline-specific role of telomeres consists of chromosome end elongation and proper chromosome segregation during early developmental stages. Despite the crucial role of telomeres in germ cells, little is known about telomere biology in the germline. We analyzed telomere homeostasis in the Drosophila female germline and early embryos. A novel germline-specific function of deadenylase complex Ccr4-Not in the telomeric transcript surveillance mechanism is reported. Depletion of Ccr4-Not complex components causes strong derepression of the telomeric retroelement HeT-A in the germ cells, accompanied by elongation of the HeT-A poly(A) tail. Dysfunction of transcription factors Woc and Trf2, as well as RNA-binding protein Ars2, also results in the accumulation of excessively polyadenylated HeT-A transcripts in ovaries. Germline knockdowns of Ccr4-Not components, Woc, Trf2 and Ars2, lead to abnormal mitosis in early embryos, characterized by chromosome missegregation, centrosome dysfunction and spindle multipolarity. Moreover, the observed phenotype is accompanied by the accumulation of HeT-A transcripts around the centrosomes in early embryos, suggesting the putative relationship between overexpression of telomeric transcripts and mitotic defects. Our data demonstrate that Ccr4-Not, Woc, Trf2 and Ars2, components of different regulatory pathways, are required for telomere protection in the germline in order to guarantee normal development. PMID:26240377

  4. A model of growth restraints to explain the development and evolution of tooth shapes in mammals.

    PubMed

    Osborn, Jeffrey W

    2008-12-01

    The problem investigated here is control of the development of tooth shape. Cells at the growing soft tissue interface between the ectoderm and mesoderm in a tooth anlage are observed to buckle and fold into a template for the shape of the tooth crown. The final shape is created by enamel secreted onto the folds. The pattern in which the folds develop is generally explained as a response to the pattern in which genes are locally expressed at the interface. This congruence leaves the problem of control unanswered because it does not explain how either pattern is controlled. Obviously, cells are subject to Newton's laws of motion so that mechanical forces and constraints must ultimately cause the movements of cells during tooth morphogenesis. A computer model is used to test the hypothesis that directional resistances to growth of the epithelial part of the interface could account for the shape into which the interface folds. The model starts with a single epithelial cell whose growth is constrained by 4 constant directional resistances (anterior, posterior, medial and lateral). The constraints force the growing epithelium to buckle and fold. By entering into the model different values for these constraints the modeled epithelium is induced to buckle and fold into the different shapes associated with the evolution of a human upper molar from that of a reptilian ancestor. The patterns and sizes of cusps and the sequences in which they develop are all correctly reproduced. The model predicts the changes in the 4 directional constraints necessary to develop and evolve from one tooth shape into another. I conclude more generally expressed genes that control directional resistances to growth, not locally expressed genes, may provide the information for the shape into which a tooth develops. PMID:18838080

  5. Roles of Bmp4 during tooth morphogenesis and sequential tooth formation

    PubMed Central

    Jia, Shihai; Zhou, Jing; Gao, Yang; Baek, Jin-A; Martin, James F.; Lan, Yu; Jiang, Rulang

    2013-01-01

    Previous studies have suggested that Bmp4 is a key Msx1-dependent mesenchymal odontogenic signal for driving tooth morphogenesis through the bud-to-cap transition. Whereas all tooth germs were arrested at the bud stage in Msx1–/– mice, we show that depleting functional Bmp4 mRNAs in the tooth mesenchyme, through neural crest-specific gene inactivation in Bmp4f/f;Wnt1Cre mice, caused mandibular molar developmental arrest at the bud stage but allowed maxillary molars and incisors to develop to mineralized teeth. We found that expression of Osr2, which encodes a zinc finger protein that antagonizes Msx1-mediated activation of odontogenic mesenchyme, was significantly upregulated in the molar tooth mesenchyme in Bmp4f/f;Wnt1Cre embryos. Msx1 heterozygosity enhanced maxillary molar developmental defects whereas Osr2 heterozygosity partially rescued mandibular first molar morphogenesis in Bmp4f/f;Wnt1Cre mice. Moreover, in contrast to complete lack of supernumerary tooth initiation in Msx1–/–Osr2–/– mice, Osr2–/–Bmp4f/f;Wnt1Cre compound mutant mice exhibited formation and subsequent arrest of supernumerary tooth germs that correlated with downregulation of Msx1 expression in the tooth mesenchyme. In addition, we found that the Wnt inhibitors Dkk2 and Wif1 were much more abundantly expressed in the mandibular than maxillary molar mesenchyme in wild-type embryos and that Dkk2 expression was significantly upregulated in the molar mesenchyme in Bmp4f/f;Wnt1Cre embryos, which correlated with the dramatic differences in maxillary and mandibular molar phenotypes in Bmp4f/f;Wnt1Cre mice. Together, these data indicate that Bmp4 signaling suppresses tooth developmental inhibitors in the tooth mesenchyme, including Dkk2 and Osr2, and synergizes with Msx1 to activate mesenchymal odontogenic potential for tooth morphogenesis and sequential tooth formation. PMID:23250216

  6. Testicular germ cell tumors.

    PubMed

    Looijenga, Leendert H J

    2014-02-01

    Human germ cell tumors are of interest because of their epidemiology, clinical behavior and pathobiology. Histologically, they are subdivided into various elements, with similarities to embryogenesis. Recent insights resulted in a division of five types of human germ cell tumors. In the context of male germ cells, three are relevant; Type I: teratomas and yolk sac tumors of neonates and infants; Type II: seminomas and nonseminomas of (predominantly) adolescents and adults; and Type III: spermatocytic seminomas of the elderly. Recent studies led to significant increases in understanding of the parameters involved in the earliest pathogenetic steps of human germ cells tumors, in particularly the seminomas and nonseminomas (Type II). In case of a disturbed gonadal physiology, either due to the germ cell itself, or the micro-environment, embryonic germ cells during a specific window of sensitization can be blocked in their maturation, resulting in carcinoma in situ or gonadoblastoma, the precursors of seminomas and nonseminomas. The level of testicularization of the gonad determines the histological composition of the precursor. These insights will allow better definition of individuals at risk to develop a germ cell malignancy, with putative preventive measurements, and allow better selection of scientific approaches to elucidate the pathogenesis. PMID:24683949

  7. Germ-granule components prevent somatic development in the C. elegans germline

    PubMed Central

    Knutson, Andrew Kekūpa'a; Egelhofer, Thea A.; Campbell, Anne C.; Strome, Susan

    2014-01-01

    Summary Specialized ribonucleoprotein organelles collectively known as germ granules are found in the germline cytoplasm from worms to humans [1]. In Drosophila, germ granules have been implicated in germline determination [2]. C. elegans germ granules, known as P granules, do not appear to be required for primordial germ cell (PGC) determination [3], but their components are still needed for fertility [4–6]. One potential role for P granules is to maintain germline fate and totipotency. This is suggested by the loss of P granules from germ cells that transform into somatic cell types, e.g. in germlines lacking MEX-3 and GLD-1 or upon neuronal induction by CHE-1 [7, 8]. However, it has not been established whether loss of P granules is the cause or effect of cell-fate transformation. To test cause-effect, we severely compromised P granules by simultaneously knocking down factors that nucleate granule formation (PGL-1 and PGL-3) and promote their perinuclear localization (GLH-1 and GLH-4) [9], and investigated if that causes germ cells to lose totipotency and initiate somatic reprogramming. We found that compromising P granules causes germ cells to express neuronal and muscle markers and send out neurite-like projections, suggesting that P granules maintain totipotency and germline identity by antagonizing somatic fate. PMID:24746798

  8. The mouse homolog of Drosophila Vasa is required for the development of male germ cells

    PubMed Central

    Tanaka, Satomi S.; Toyooka, Yayoi; Akasu, Ryuko; Katoh-Fukui, Yuko; Nakahara, Yoko; Suzuki, Rika; Yokoyama, Minesuke; Noce, Toshiaki

    2000-01-01

    Restricted expression of a mouse Vasa homolog gene (Mvh) expression is first detected in primordial germ cells (PGCs) after colonization of the genital ridges. Subsequently, Mvh is maintained until postmeiotic germ cells are formed. Here, we demonstrate that male mice homozygous for a targeted mutation of Mvh exhibit a reproductive deficiency. Male homozygotes produce no sperm in the testes, where premeiotic germ cells cease differentiation by the zygotene stage and undergo apoptotic death. In addition, the proliferation of PGCs that colonize homozygous male gonads is significantly hampered, and OCT-3/4 expression appears to be reduced. These results indicate that the loss of Mvh function causes a deficiency in the proliferation and differentiation of mouse male germ cells. PMID:10766740

  9. Development and Evolution of Dentition Pattern and Tooth Order in the Skates And Rays (Batoidea; Chondrichthyes)

    PubMed Central

    Underwood, Charlie J.; Johanson, Zerina; Welten, Monique; Metscher, Brian; Rasch, Liam J.; Fraser, Gareth J.; Smith, Moya Meredith

    2015-01-01

    Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays), hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic) spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files), presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth) and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as well as the

  10. Development of space-fertilized eggs and formation of primordial germ cells in the embryos of medaka fish

    NASA Astrophysics Data System (ADS)

    Ijiri, K.

    In the second International Microgravity Laboratory (IML-2) mission in 1994, four small Japanese killifish (Medaka, Oryzias latipes) made a space travel of 15 days aboard a space shuttle. These four adult Medaka fish successfully mated in space for the first time among vertebrate animals. Moreover, the eggs they laid developed normally, at least in their external appearance, hatching as fry (baby fish) in space. Fish mated and laid eggs every day during the first week. Near the end of the mission most of the eggs had a well-developed body with two pigmented eyes. In total, 43 eggs were laid (detected), out of which 8 fry hatched in space, as truly `space-originated' babies. A further 30 fry hatched within 3 days after landing. This is the normal hatching rate, compared with the ground-based data. Among the 8 space-originated fry, four were killed for histological sections, and germ cells at the gonadal region were counted for each fry. Their numbers were in the range of the germ cells of the normal control fry (ground-kept samples). Thus, as embryos developed normally in their external appearance, inside the embryos the formation of primordial germ cells took place normally in space, and their migration to the genital ridges was not hindered by microgravity. The two of the remaining space-originated fry have grown up and been creating their offspring in the laboratory. This proved that the primordial germ cells formed in space were also normal from a functional point of view. The four space-travelled adult fish re-started mating and laying eggs on the 7th day after landing and continued to do so every day afterward. Fertilization rate and hatchability of these eggs were as high as the eggs laid by the laboratory-kept fish. This fact implies that in gametogenesis of adult fish, there are no specific stages of germ cells extremely susceptible to microgravity.

  11. NANOG promoter methylation and expression correlation during normal and malignant human germ cell development

    PubMed Central

    Nettersheim, Daniel; Bierman, Katharina; Gillis, Ad JM; Steger, Klaus; Looijenga, Leendert HJ

    2011-01-01

    Testicular germ cell tumors are the most frequent malignant tumors in young Caucasian males, with increasing incidence. The actual model of tumorigenesis is based on the theory that a block in maturation of fetal germ cells lead to formation of the intratubular germ cell neoplasia unclassified. Early fetal germ cells and undifferentiated germ cell tumors express pluripotency markers such as the transcription factor NANOG. It has been demonstrated that epigenetic modifications, such as promoter DNA methylation, are able to silence gene expression in normal and cancer cells. Here we show that OCT3/4-SOX2 mediated expression of NANOG can be silenced by methylation of promoter CpG-sites. We found that global methylation of DNA decreased from fetal spermatogonia to mature sperm. In contrast, CpGs in the NANOG promoter were found hypomethylated in spermatogonia and hypermethylated in sperm. This selective repression might reflect the cells need to suppress pluripotency in order to prevent malignant transformation. Finally, methylation of CpGs in the NANOG promoter in germ cell tumors and derived cell lines correlated to differentiation state. PMID:20930529

  12. Comparative Effects of Di(n-Butyl) Phthalate Exposure on Fetal Germ Cell Development in the Rat and in Human Fetal Testis Xenografts

    PubMed Central

    McKinnell, Chris; Calarrão, Ana; Kennedy, Laura; Hutchison, Gary R.; Hrabalkova, Lenka; Jobling, Matthew S.; Macpherson, Sheila; Anderson, Richard A.; Sharpe, Richard M.; Mitchell, Rod T.

    2014-01-01

    , Sharpe RM, Mitchell RT. 2015. Comparative effects of di(n-butyl) phthalate exposure on fetal germ cell development in the rat and in human fetal testis xenografts. Environ Health Perspect 123:223–230; http://dx.doi.org/10.1289/ehp.1408248 PMID:25514601

  13. Analgesic exposure in pregnant rats affects fetal germ cell development with inter-generational reproductive consequences

    PubMed Central

    Dean, Afshan; van den Driesche, Sander; Wang, Yili; McKinnell, Chris; Macpherson, Sheila; Eddie, Sharon L.; Kinnell, Hazel; Hurtado-Gonzalez, Pablo; Chambers, Tom J.; Stevenson, Kerrie; Wolfinger, Elke; Hrabalkova, Lenka; Calarrao, Ana; Bayne, Rosey AL; Hagen, Casper P.; Mitchell, Rod T.; Anderson, Richard A.; Sharpe, Richard M.

    2016-01-01

    Analgesics which affect prostaglandin (PG) pathways are used by most pregnant women. As germ cells (GC) undergo developmental and epigenetic changes in fetal life and are PG targets, we investigated if exposure of pregnant rats to analgesics (indomethacin or acetaminophen) affected GC development and reproductive function in resulting offspring (F1) or in the F2 generation. Exposure to either analgesic reduced F1 fetal GC number in both sexes and altered the tempo of fetal GC development sex-dependently, with delayed meiotic entry in oogonia but accelerated GC differentiation in males. These effects persisted in adult F1 females as reduced ovarian and litter size, whereas F1 males recovered normal GC numbers and fertility by adulthood. F2 offspring deriving from an analgesic-exposed F1 parent also exhibited sex-specific changes. F2 males exhibited normal reproductive development whereas F2 females had smaller ovaries and reduced follicle numbers during puberty/adulthood; as similar changes were found for F2 offspring of analgesic-exposed F1 fathers or mothers, we interpret this as potentially indicating an analgesic-induced change to GC in F1. Assuming our results are translatable to humans, they raise concerns that analgesic use in pregnancy could potentially affect fertility of resulting daughters and grand-daughters. PMID:26813099

  14. Bisphosphonates: Pharmacokinetics, bioavailability, mechanisms of action, clinical applications in children, and effects on tooth development.

    PubMed

    Soares, Ana Prates; do Espírito Santo, Renan Fernandes; Line, Sérgio Roberto Peres; Pinto, Maria das Graças Farias; Santos, Pablo de Moura; Toralles, Maria Betânia Pereira; do Espírito Santo, Alexandre Ribeiro

    2016-03-01

    Bisphosphonates (BPs) avidly bind to calcium crystals and inhibit osteoclastic bone resorption, making them useful for treatment of skeletal disorders such as osteoporosis, Paget's disease, osteogenesis imperfecta and metastatic bone diseases. BPs therapeutically act by causing toxic effects on osteoclasts or interfering with specific intracellular pathways in those cells. BPs that possess nitrogen in their composition are called nitrogen-containing BPs (NBPs) and include alendronate, pamidronate, risedronate, ibandronate, and zoledronate. Simple BPs or non-NBPs do not have nitrogen in their composition, include etiodronate and clodronate, and were the first to be tested in animals and clinically used. Because BPs may be administered to pregnant women or children during deciduous and permanent teeth development, it is expected that they might disturb tooth eruption and development. A review of current literature on pharmacokinetics, bioavailability, mechanisms of action, and clinical applications of BPs in children, and their effects on tooth eruption and development is presented. PMID:26895384

  15. Impairment of Bony Crypt Development Associated With Hexavalent Chromium Exposure During Tooth Eruption.

    PubMed

    Sánchez, Luciana M; Lewicki, Marianela; De Lucca, Romina C; Ubios, Ángela M

    2015-12-01

    Improperly treated hexavalent chromium-containing industrial wastes contaminate drinking water, potentially affecting children taking breast milk or baby bottles prepared with infant formula. Thus, the aim of the present work was to determine the effect of this toxic on bone activity in the developing alveolus during tooth eruption of suckling Wistar rats intoxicated with potassium dichromate. Experimental animals received a daily dose of 12.5mg/kg body weight of potassium dichromate by gavage for 10 days; controls received an equivalent volume of saline solution. Histologic and histomorphometric studies of the mandible were performed. The data were statistically analyzed using Student's t test; statistical significance was set at a value of p <0.05. Experimental animals exhibited delayed tooth eruption, decreased periodontal width and bone volume, a lower percentage of bone formation surfaces, and higher percentage of quiescent surfaces (p<0.05) compared to controls. The delay in tooth eruption observed after exposure to hexavalent chromium is the result of a lower rate of bone remodeling in the developing alveolus. The obtained results show the importance of controlling toxic substances in drinking water, since their effects may alter the growth and development of subjects who were exposed during early infancy. PMID:27095619

  16. Redeployment of germ layers related TFs shows regionalized expression during two non-embryonic developments.

    PubMed

    Ricci, Lorenzo; Cabrera, Fabien; Lotito, Sonia; Tiozzo, Stefano

    2016-08-01

    In all non-vertebrate metazoan phyla, species that evolved non-embryonic developmental pathways as means of propagation or regeneration can be found. In this context, new bodies arise through asexual reproduction processes (such as budding) or whole body regeneration, that lack the familiar temporal and spatial cues classically associated with embryogenesis, like maternal determinants, or gastrulation. The molecular mechanisms underlying those non-embryonic developments (i.e., regeneration and asexual reproduction), and their relationship to those deployed during embryogenesis are poorly understood. We have addressed this question in the colonial ascidian Botryllus schlosseri, which undergoes an asexual reproductive process via palleal budding (PB), as well as a whole body regeneration by vascular budding (VB). We identified early regenerative structures during VB and then followed the fate of differentiating tissues during both non-embryonic developments (PB and VB) by monitoring the expression of genes known to play key functions in germ layer specification with well conserved expression patterns in solitary ascidian embryogenesis. The expression patterns of FoxA1, GATAa, GATAb, Otx, Bra, Gsc and Tbx2/3 were analysed during both PB and VB. We found that the majority of these transcription factors were expressed during both non-embryonic developmental processes, revealing a regionalization of the palleal and vascular buds. Knockdown of GATAa by siRNA in palleal buds confirmed that preventing the correct development of one of these regions blocks further tissue specification. Our results indicate that during both normal and injury-induced budding, a similar alternative developmental program operates via early commitment of epithelial regions. PMID:27208394

  17. Analysis of TET Expression/Activity and 5mC Oxidation during Normal and Malignant Germ Cell Development

    PubMed Central

    Nettersheim, Daniel; Heukamp, Lukas C.; Fronhoffs, Florian; Grewe, Marc J.; Haas, Natalie; Waha, Anke; Honecker, Friedemann; Waha, Andreas; Kristiansen, Glen; Schorle, Hubert

    2013-01-01

    During mammalian development the fertilized zygote and primordial germ cells lose their DNA methylation within one cell cycle leading to the concept of active DNA demethylation. Recent studies identified the TET hydroxylases as key enzymes responsible for active DNA demethylation, catalyzing the oxidation of 5-methylcytosine to 5-hydroxymethylcytosine. Further oxidation and activation of the base excision repair mechanism leads to replacement of a modified cytosine by an unmodified one. In this study, we analyzed the expression/activity of TET1-3 and screened for the presence of 5mC oxidation products in adult human testis and in germ cell cancers. By analyzing human testis sections, we show that levels of 5-hydroxymethylcytosine, 5-formylcytosine and 5-carboxylcytosine are decreasing as spermatogenesis proceeds, while 5-methylcytosine levels remain constant. These data indicate that during spermatogenesis active DNA demethylation becomes downregulated leading to a conservation of the methylation marks in mature sperm. We demonstrate that all carcinoma in situ and the majority of seminomas are hypomethylated and hypohydroxymethylated compared to non-seminomas. Interestingly, 5-formylcytosine and 5-carboxylcytosine were detectable in all germ cell cancer entities analyzed, but levels did not correlate to the 5-methylcytosine or 5-hydroxymethylcytosine status. A meta-analysis of gene expression data of germ cell cancer tissues and corresponding cell lines demonstrates high expression of TET1 and the DNA glycosylase TDG, suggesting that germ cell cancers utilize the oxidation pathway for active DNA demethylation. During xenograft experiments, where seminoma-like TCam-2 cells transit to an embryonal carcinoma-like state DNMT3B and DNMT3L where strongly upregulated, which correlated to increasing 5-methylcytosine levels. Additionally, 5-hydroxymethylcytosine levels were elevated, demonstrating that de novo methylation and active demethylation accompanies this transition

  18. Development of dental charts according to tooth development and eruption for Turkish children and young adults

    PubMed Central

    Afşin, Hüseyin; Ozaslan, Abdi; Karadayı, Şükriye

    2014-01-01

    Purpose In this study, we aimed to develop dental charts for Turkish children and young adults of both genders within the age group of 4.5-22.5 years according to tooth mineralization and eruption in a format similar to that proposed by AlQahtani et al. Materials and Methods In total, 753 digital panoramic radiographs from 350 males and 403 females were assessed. The permanent teeth were evaluated according to the classification system described by Demirjian et al. The eruption stage was assessed with Bengston's system, which was modified by AlQahtani et al at four points. Results Teeth generally developed earlier in females than in males. This was particularly notable in the age group of 5-14 years. However, this difference was usually visible in only one stage, not in all teeth. It has been determined that the mixed dentition period ended with the shedding of the second deciduous molars in both genders. Conclusion The dental charts presented here included information that could be beneficial to dental clinicians in making appropriate diagnosis and planning orthodontic and surgical procedures. These charts also provided datasets for preliminary dental age estimation in Turkish children and young adults. PMID:24944959

  19. The development of a "Green" aqueous enzymatic process to extract corn oil from corn germ

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Approximately 2.4 million tons of commercial corn oil were produced worldwide in 2012, compared to 2012 world production of palm oil (53.3 MT) and soybean oil (43.1 MT) according to FAS, USDA. Most commercial corn oil (~90%) is produced from corn germ that is expeller pressed and/or hexane extracte...

  20. Natural selection and molecular evolution in primate PAX9 gene, a major determinant of tooth development

    PubMed Central

    Pereira, Tiago V.; Salzano, Francisco M.; Mostowska, Adrianna; Trzeciak, Wieslaw H.; Ruiz-Linares, Andrés; Chies, José A. B.; Saavedra, Carmen; Nagamachi, Cleusa; Hurtado, Ana M.; Hill, Kim; Castro-de-Guerra, Dinorah; Silva-Júnior, Wilson A.; Bortolini, Maria-Cátira

    2006-01-01

    Large differences in relation to dental size, number, and morphology among and within modern human populations and between modern humans and other primate species have been observed. Molecular studies have demonstrated that tooth development is under strict genetic control, but, the genetic basis of primate tooth variation remains unknown. The PAX9 gene, which codes for a paired domain-containing transcription factor that plays an essential role in the development of mammal dentition, has been associated with selective tooth agenesis in humans and mice, which mainly involves the posterior teeth. To determine whether this gene is polymorphic in humans, we sequenced ≈2.1 kb of the entire four-exon region (exons 1, 2, 3 and 4; 1,026 bp) and exon-intron (1.1 kb) boundaries of 86 individuals sampled from Asian, European, and Native American populations. We provided evidence that human PAX9 polymorphisms are limited to exon 3 only and furnished details about the distribution of a mutation there in 350 Polish subjects. To investigate the pattern of selective pressure on exon 3, we sequenced ortholog regions of this exon in four species of New World monkeys and one gorilla. In addition, orthologous sequences of PAX9 available in public databases were also analyzed. Although several differences were identified between humans and other species, our findings support the view that strong purifying selection is acting on PAX9. New World and Old World primate lineages may, however, have different degrees of restriction for changes in this DNA region. PMID:16585527

  1. Twist1 Is Essential for Tooth Morphogenesis and Odontoblast Differentiation.

    PubMed

    Meng, Tian; Huang, Yanyu; Wang, Suzhen; Zhang, Hua; Dechow, Paul C; Wang, Xiaofang; Qin, Chunlin; Shi, Bing; D'Souza, Rena N; Lu, Yongbo

    2015-12-01

    Twist1 is a basic helix-loop-helix-containing transcription factor that is expressed in the dental mesenchyme during the early stages of tooth development. To better delineate its roles in tooth development, we generated Twist1 conditional knockout embryos (Twist2(Cre) (/+);Twist1(fl/fl)) by breeding Twist1 floxed mice (Twist1(fl/fl)) with Twist2-Cre recombinase knockin mice (Twist2(Cre) (/+)). The Twist2(Cre) (/+);Twist1(fl/fl) embryos formed smaller tooth germs and abnormal cusps during early tooth morphogenesis. Molecular and histological analyses showed that the developing molars of the Twist2(Cre) (/+);Twist1(fl/fl) embryos had reduced cell proliferation and expression of fibroblast growth factors 3, 4, 9, and 10 and FGF receptors 1 and 2 in the dental epithelium and mesenchyme. In addition, 3-week-old renal capsular transplants of embryonic day 18.5 Twist2(Cre) (/+);Twist1(fl/fl) molars showed malformed crowns and cusps with defective crown dentin and enamel. Immunohistochemical analyses revealed that the implanted mutant molars had defects in odontoblast differentiation and delayed ameloblast differentiation. Furthermore, in vitro ChIP assays demonstrated that Twist1 was able to bind to a specific region of the Fgf10 promoter. In conclusion, our findings suggest that Twist1 plays crucial roles in regulating tooth development and that it may exert its functions through the FGF signaling pathway. PMID:26487719

  2. Extraction and characterization of corn germ proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our study was conducted to develop methods to extract corn germ protein economically and characterize and identify potential applications of the recovered protein. Protein was extracted from both wet germ and finished (dried) germ using 0.1M NaCl as solvent. The method involved homogenization, sti...

  3. Identification of Potential Germ-Cell Mutagens

    EPA Science Inventory

    The existence of agents that can induce germ-cell mutations in experimental systems has been recognized since 1927 with the discovery of the ability of X-rays to induce such mutations in Drosophila. Various rodent-based germ-cell mutation assays have been developed, and ~50 germ...

  4. Expression of FGFR3 during human testis development and in germ cell-derived tumours of young adults.

    PubMed

    Ewen, Katherine A; Olesen, Inge A; Winge, Sofia B; Nielsen, Ana R; Nielsen, John E; Graem, Niels; Juul, Anders; Rajpert-De Meyts, Ewa

    2013-01-01

    Observations in patients with an activating mutation of fibroblast growth factor receptor 3 (FGFR3) suggest a role for FGFR3 signalling in promoting proliferation or survival of germ cells. In this study, we aimed to identify the FGFR3 subtype and the ontogeny of expression during human testis development and to ascertain whether FGFR3 signalling is linked to germ cell proliferation and the pathogenesis of testicular germ cell tumours (TGCTs) of young adult men. Using RT-PCR, immunohistochemistry and Western blotting, we examined 58 specimens of human testes throughout development for FGFR3 expression, and then compared expression of FGFR3 with proliferation markers (PCNA or Ki67). We also analysed for FGFR3 expression 30 TGCTs and 28 testes containing the tumour precursor cell, carcinoma in situ (CIS). Fetal and adult testes expressed exclusively the FGFR3IIIc isoform. FGFR3 protein expression was restricted to the cytoplasm/plasma membrane of spermatogonia and was most prevalent at mid-gestation, infancy and from puberty onwards. Phosphorylated (p)FGFR was detected in pre-spermatogonia at mid-gestation and in spermatogonia during puberty and in the adult testis. Throughout normal human testis development, expression of FGFR3 did not directly correlate with proliferation markers. In preinvasive CIS cells and in TGCTs, including classical seminoma and embryonal carcinoma, FGFR3IIIc was detected only in a small number of cells, with a heterogeneous expression pattern. FGFR3 is an excellent marker for human pre-/spermatogonia throughout development. Signalling through this receptor is likely associated with spermatogonial survival rather than proliferation. FGFR3 is not expressed in gonocytes and may not be essential to the aetiology of TGCTs stemming from CIS. PMID:23784824

  5. Disruption of Wnt/β-catenin Signaling in Odontoblasts and Cementoblasts Arrests Tooth Root Development in Postnatal Mouse Teeth

    PubMed Central

    Zhang, Ran; Yang, Guan; Wu, Ximei; Xie, Jing; Yang, Xiao; Li, Tiejun

    2013-01-01

    Tooth development undergoes a series of complex reciprocal interactions between dental epithelium and the underlying mesenchymal cells. Compared with the study in tooth crown formation, little is known about the molecular mechanism underlying the development of tooth roots. In the present study, we conditionally knock out β-catenin gene (Ctnnb1) within developing odontoblasts and cementoblasts during the development of tooth roots, and observed rootless molars as well as incomplete incisors. Histological analyses revealed intact structure of molar crown and labial side of incisor, however, as for the molar roots and the lingual portion of incisor, the formation of dentin and periodontal tissues were greatly hampered. In situ hybridization experiments using probes of odontoblastic marker genes collagen type I, alpha 1 (Col1a1), osteocalcin (OC) and dentin sialophosphoprotein (Dspp) manifested striking undifferentiation of root odontoblasts in which Ctnnb1 was eliminated. Bromodeoxyuridine (BrdU) labeling and proliferating cell nuclear antigen (PCNA) immunohistochemical experiments also showed retarded proliferation of pre-odontoblasts in mutant mice. However, cell apoptosis was not affected. Additionally, a disrupted formation of cementoblasts, suggested by the absence of transcripts of bone sialoprotein (Bsp) in follicle mesenchyme, was also evident in mutant mice. Our study provides strong in vivo evidence to confirm that Wnt/β-catenin signaling is functionally significant to root odontogenesis and cementogenesis during the tooth root development. PMID:23494738

  6. Tooth Disorders

    MedlinePlus

    ... made of a hard, bonelike material. Inside the tooth are nerves and blood vessels. You need your ... These include eating, speaking and even smiling. But tooth disorders are nothing to smile about. They include ...

  7. Tooth abscess

    MedlinePlus

    ... swelling within the tooth. This causes a painful toothache . The toothache may stop if the pulp of the tooth ... tissue. Symptoms The main symptom is a severe toothache. The pain is continuous. It can be described ...

  8. Tooth anatomy

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002214.htm Tooth anatomy To use the sharing features on this page, ... upper jawbone is called the maxilla. Images Tooth anatomy References Lingen MW. Head and neck. In: Kumar ...

  9. Tooth Disorders

    MedlinePlus

    ... These include eating, speaking and even smiling. But tooth disorders are nothing to smile about. They include problems ... with your teeth. Fortunately, you can prevent many tooth disorders by taking care of your teeth and keeping ...

  10. Limb, tooth, beak: three modes of development and evolutionary innovation of form.

    PubMed

    Linde-Medina, Marta; Newman, Stuart A

    2014-04-01

    The standard model of evolutionary change of form, deriving from Darwin's theory via the Modern Synthesis, assumes a gradualistic reshaping of anatomical structures, with major changes only occurring by many cycles of natural selection for marginal adaptive advantage. This model, with its assertion that a single mechanism underlies both micro- and macroevolutionary change, contains an implicit notion of development which is only applicable in some cases. Here we compare the embryological processes that shape the vertebrate limb bud, the mammalian tooth and the avian beak. The implied notion of development in the standard evolutionary picture is met only in the case of the vertebrate limb, a single-primordium organ with morphostatic shaping, in which cells rearrange in response to signalling centres which are essentially unchanged by cell movement. In the case of the tooth, a single-primordium organ with morphodynamic shaping in which the strengths and relationships between signalling centres is influenced by the cell and tissue movements they induce, and the beak, in which the final form is influenced by the collision and rearrangement of multiple tissue primordia, abrupt appearance of qualitatively different forms (i.e. morphological novelties) can occur with small changes in system parameters induced by a genetic change, or by an environmental factor whose effects can be subsequently canalized genetically. Bringing developmental mechanisms and, specifically, the material properties of tissues as excitable media into the evolutionary picture, demonstrates that gradualistic change for incremental adaptive advantage is only one of the possible modes of morphological evolution. PMID:24736155

  11. Development of In Vivo Tooth EPR for Individual Radiation Dose Estimation and Screening

    PubMed Central

    Williams, Benjamin B.; Dong, Ruhong; Kmiec, Maciej; Burke, Greg; Demidenko, Eugene; Gladstone, David; Nicolalde, Roberto J; Sucheta, Artur; Lesniewski, Piotr; Swartz, Harold M

    2009-01-01

    The development of in vivo EPR has made it feasible to perform tooth dosimetry measurements in situ, greatly expanding the potential for using this approach for immediate screening after radiation exposures. The ability of in vivo tooth dosimetry to provide estimates of absorbed dose has been established through a series of experiments using unirradiated volunteers with specifically irradiated molar teeth placed in situ within gaps in their dentition and in natural canine teeth of patients who have completed courses of radiation therapy for head and neck cancers. Multiple measurements in patients who have received radiation therapy demonstrate the expected heterogeneous dose distributions. Dose response curves have been generated using both populations and, using the current methodology and instrument, the standard error of prediction based on single 4.5 minute measurements is approximately 1.5 Gy for inserted molar teeth and between 2.0 and 2.5 Gy in the more irregularly shaped canine teeth. Averaging of independent measurements can reduce this error significantly to values near 1 Gy. Developments to reduce these errors are underway, focusing on geometric optimization of the resonators, detector positioning techniques, and optimal data averaging approaches. In summary, it seems plausible that the EPR dosimetry techniques will have an important role in retrospective dosimetry for exposures involving large numbers of individuals. PMID:20065702

  12. New Developed Cylindrical TM010 Mode EPR Cavity for X-Band In Vivo Tooth Dosimetry

    PubMed Central

    Junwang, Guo; Qingquan, Yuan; Jianbo, Cong; Lei, Ma; Guofu, Dong; Guoshan, Yang; Ke, Wu

    2014-01-01

    EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity’s cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed. Theoretical calculations and simulations were used to design and optimize the cavity parameters. The cavity features were evaluated by measuring DPPH sample, intact incisor samples embed in a gum model and the rhesus monkey teeth. The results showed that the cavity worked at designed frequency and had the ability to make EPR spectroscopy in relative high sensitivity. Sufficient modulation amplitude and microwave power could be applied into the aperture. Radiation induced EPR signal could be observed remarkably from 1 Gy irradiated intact incisor within only 30 seconds, which was among the best in scan time and detection limit. The in vivo spectroscopy was also realized by acquiring the radiation induced EPR signal from teeth of rhesus monkey whose teeth was irradiated by dose of 2 Gy. The results suggested that the cavity was sensitive to meet the demand to assess doses of significant level in short time. This cavity provided a very potential option for the development of X-band in vivo dosimetry. PMID:25222483

  13. New developed cylindrical TM010 mode EPR cavity for X-band in vivo tooth dosimetry.

    PubMed

    Junwang, Guo; Qingquan, Yuan; Jianbo, Cong; Lei, Ma; Guofu, Dong; Guoshan, Yang; Ke, Wu

    2014-01-01

    EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity's cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed. Theoretical calculations and simulations were used to design and optimize the cavity parameters. The cavity features were evaluated by measuring DPPH sample, intact incisor samples embed in a gum model and the rhesus monkey teeth. The results showed that the cavity worked at designed frequency and had the ability to make EPR spectroscopy in relative high sensitivity. Sufficient modulation amplitude and microwave power could be applied into the aperture. Radiation induced EPR signal could be observed remarkably from 1 Gy irradiated intact incisor within only 30 seconds, which was among the best in scan time and detection limit. The in vivo spectroscopy was also realized by acquiring the radiation induced EPR signal from teeth of rhesus monkey whose teeth was irradiated by dose of 2 Gy. The results suggested that the cavity was sensitive to meet the demand to assess doses of significant level in short time. This cavity provided a very potential option for the development of X-band in vivo dosimetry. PMID:25222483

  14. Tooth anatomy

    MedlinePlus

    The part of the tooth you can see is called the crown. The outer surface of the crown is made of enamel. Just beneath the ... The gum surrounds the base (root) of the tooth. The root of the tooth extends down into ...

  15. Involvement of doublesex and mab-3-related transcription factors in human female germ cell development demonstrated by xenograft and interference RNA strategies.

    PubMed

    Poulain, Marine; Frydman, Nelly; Tourpin, Sophie; Muczynski, Vincent; Mucsynski, Vincent; Souquet, Benoit; Benachi, Alexandra; Habert, René; Rouiller-Fabre, Virginie; Livera, Gabriel

    2014-10-01

    We identified three doublesex and mab-3-related transcription factors (DMRT) that were sexually differentially expressed in human fetal gonads and present in the ovaries at the time of meiotic initiation. These were also identified in murine embryonic female germ cells. Among these, we focused on DMRTA2 (DMRT5), whose function is unknown in the developing gonads, and clarified its role in human female fetal germ cells, using an original xenograft model. Early human fetal ovaries (8-11 weeks post-fertilization) were grafted into nude mice. Grafted ovaries developed normally, with no apparent overt changes, when compared with ungrafted ovaries at equivalent developmental stages. Appropriate germ cell density, mitotic/meiotic transition, markers of meiotic progression and follicle formation were evident. Four weeks after grafting, mice were treated with siRNA, specifically targeting human DMRTA2 mRNA. DMRTA2 inhibition triggered an increase in undifferentiated FUT4-positive germ cells and a decrease in the percentage of meiotic γH2AX-positive germ cells, when compared with mice that were injected with control siRNA. Interestingly, the expression of markers associated with pre-meiotic germ cell differentiation was also impaired, as was the expression of DMRTB1 (DMRT6) and DMRTC2 (DMRT7). This study reveals, for the first time, the requirement of DMRTA2 for normal human female embryonic germ cell development. DMRTA2 appears to be necessary for proper differentiation of oogonia, prior to entry into meiosis, in the human species. Additionally, we developed a new model of organ xenografting, coupled with RNA interference, which provides a useful tool for genetic investigations of human germline development. PMID:25082981

  16. Melatonin promotes development of haploid germ cells from early developing spermatogenic cells of Suffolk sheep under in vitro condition.

    PubMed

    Deng, Shou-Long; Chen, Su-Ren; Wang, Zhi-Peng; Zhang, Yan; Tang, Ji-Xin; Li, Jian; Wang, Xiu-Xia; Cheng, Jin-Mei; Jin, Cheng; Li, Xiao-Yu; Zhang, Bao-Lu; Yu, Kun; Lian, Zheng-Xing; Liu, Guo-Shi; Liu, Yi-Xun

    2016-05-01

    Promotion of spermatogonial stem cell (SSC) differentiation into functional sperms under in vitro conditions is a great challenge for reproductive physiologists. In this study, we observed that melatonin (10(-7) m) supplementation significantly enhanced the cultured SSCs differentiation into haploid germ cells. This was confirmed by the expression of sperm special protein, acrosin. The rate of SSCs differentiation into sperm with melatonin supplementation was 11.85 ± 0.93% which was twofold higher than that in the control. The level of testosterone, the transcriptions of luteinizing hormone receptor (LHR), and the steroidogenic acute regulatory protein (StAR) were upregulated with melatonin treatment. At the early stage of SSCs culture, melatonin suppressed the level of cAMP, while at the later stage, it promoted cAMP production. The similar pattern was observed in testosterone content. Expressions for marker genes of meiosis anaphase, Dnmt3a, and Bcl-2 were upregulated by melatonin. In contrast, Bax expression was downregulated. Importantly, the in vitro-generated sperms were functional and they were capable to fertilize oocytes. These fertilized oocytes have successfully developed to the blastula stage. PMID:26993286

  17. Accuracy of developing tooth length as an estimate of age in human skeletal remains: the deciduous dentition.

    PubMed

    Cardoso, Hugo F V

    2007-10-01

    Dental age assessments are widely used to estimate age of immature skeletal remains. Most methods have relied on fractional stages of tooth emergence and formation, particularly of the permanent dentition, for predicting the age of infants and very young children. In this study, the accuracy of regression equations of developing deciduous tooth length for age estimation (Liversidge et al.) is tested on a sample of 30 Portuguese subadult skeletons of known age at death. Overall the method shows high accuracy and the average difference between estimated and chronological age is between 0.20 and -0.14 years when using single teeth, and 0.06 years, when using all available teeth. However, there is a tendency for the deciduous molars to provide overestimates of chronological age. Results show that age estimates can be obtained within +/-0.10 years with a 95% confidence interval when several teeth are used. Overall between-tooth agreement in age estimates decreases with increasing age but there is less variability of estimates with more teeth contributing to overall mean age. One seemingly limitation of this method may be the fact that it was developed by combining the maxillary and mandibular teeth. The other is related to the accuracy with which radiographic tooth length can be used as a valid surrogate for actual tooth length. Nevertheless, the advantages of this metric method surpass the limitations of chronologies based on stages of dental development. PMID:17174050

  18. Altered miRNA Signature of Developing Germ-cells in Infertile Patients Relates to the Severity of Spermatogenic Failure and Persists in Spermatozoa

    PubMed Central

    Muñoz, Xavier; Mata, Ana; Bassas, Lluís; Larriba, Sara

    2015-01-01

    The aim of this study was to assess the cellular miRNA expression behaviour in testes with spermatogenic failure (SpF). We performed a high-throughput screen of 623 mature miRNAs by a quantitative RT-qPCR-based approach in histologically well-defined testicular samples with spermatogenic disruption at different germ-cell stages, which revealed altered patterns of miRNA expression. We focussed on the differentially expressed miRNAs whose expression correlated with the number of testicular mature germ-cells and described the combined expression values of a panel of three miRNAs (miR-449a, miR-34c-5p and miR-122) as a predictive test for the presence of mature germ-cells in testicular biopsy. Additionally, we determined decreased cellular miRNA content in developing germ-cells of SpF testis; this was more noticeable the earlier the stage of germ-cell differentiation was affected by maturation failure. Furthermore, we showed that the miRNA expression profile in mature sperm from mild SpF patients was widely altered. Our results suggest that the cellular miRNA content of developed germ-cells depends heavily on the efficacy of the spermatogenic process. What is more, spermatozoa that have fulfilled the differentiation process still retain the dysregulated miRNA pattern observed in the developing SpF germ-cells. This altered miRNA molecular signature may have functional implications for the male gamete. PMID:26648257

  19. Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur.

    PubMed

    Liu, Min; Reed, David A; Cecchini, Giancarlo M; Lu, Xuanyu; Ganjawalla, Karan; Gonzales, Carol S; Monahan, Richard; Luan, Xianghong; Diekwisch, Thomas G H

    2016-01-01

    Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here, we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids vs. snakes: (i) the orientation of replacement teeth compared to the major tooth axis, (ii) the occurrence of resorption pits, and (iii) the mode of tooth implantation/attachment to the tooth bearing element (TBE). The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as Heloderma. In

  20. Varanoid Tooth Eruption and Implantation Modes in a Late Cretaceous Mosasaur

    PubMed Central

    Liu, Min; Reed, David A.; Cecchini, Giancarlo M.; Lu, Xuanyu; Ganjawalla, Karan; Gonzales, Carol S.; Monahan, Richard; Luan, Xianghong

    2016-01-01

    Erupting teeth are some of the oldest witnesses of developmental processes in the vertebrate fossil record and provide an important resource for vertebrate cladistics. Here, we have examined a mosasaur jaw fragment from central Texas using ultrathin ground section histology and 3D tomographic imaging to assess features critical for the cladistic placement of mosasaurs among varanoids vs. snakes: (i) the orientation of replacement teeth compared to the major tooth axis, (ii) the occurrence of resorption pits, and (iii) the mode of tooth implantation/attachment to the tooth bearing element (TBE). The replacement tooth studied here developed in an inclined position slightly distal of the deciduous parent tooth, similar to another varanoid squamate, the Gila monster Heloderma suspectum. Ground sections and tomographs also demonstrated that the replacement tooth attachment apparatus was entirely intact and that there was no evidence of mechanical deformation. Sections and tomographs further illustrated that the replacement tooth was located within a bony crypt and the inclination of the crypt matched the inclination of the replacement tooth. These preparations also revealed the presence of a resorption pit within the boundaries of the deciduous tooth that surrounded the developing replacement tooth. This finding suggests that developing mosasaur teeth developed within the walls of resorption pits similar to varanoid tooth germs and unlike developing snake teeth which are surrounded by fibrous connective tissue integuments. Finally, mosasaurs featured pseudo-thecodont tooth implantation with teeth anchored within a socket of mineralized tissue by means of a mineralized periodontal ligament. Together, these data indicate that the moderate inclination of the erupting mosasaur tooth studied here is neither a result of postmortem displacement nor a character representative of snakes, but rather a shared character between Mosasaurs and other varanoids such as Heloderma. In

  1. The role of evolutionarily conserved germ-line DH sequence in B-1 cell development and natural antibody production.

    PubMed

    Vale, Andre M; Nobrega, Alberto; Schroeder, Harry W

    2015-12-01

    Because of N addition and variation in the site of VDJ joining, the third complementarity-determining region of the heavy chain (CDR-H3) is the most diverse component of the initial immunoglobulin antigen-binding site repertoire. A large component of the peritoneal cavity B-1 cell component is the product of fetal and perinatal B cell production. The CDR-H3 repertoire is thus depleted of N addition, which increases dependency on germ-line sequence. Cross-species comparisons have shown that DH gene sequence demonstrates conservation of amino acid preferences by reading frame. Preference for reading frame 1, which is enriched for tyrosine and glycine, is created both by rearrangement patterns and by pre-BCR and BCR selection. In previous studies, we have assessed the role of conserved DH sequence by examining peritoneal cavity B-1 cell numbers and antibody production in BALB/c mice with altered DH loci. Here, we review our finding that changes in the constraints normally imposed by germ-line-encoded amino acids within the CDR-H3 repertoire profoundly affect B-1 cell development, especially B-1a cells, and thus natural antibody immunity. Our studies suggest that both natural and somatic selection operate to create a restricted B-1 cell CDR-H3 repertoire. PMID:26104486

  2. The Geochemical Earth Reference Model (GERM)

    SciTech Connect

    Staudigel, H.; Albarede, F.; Shaw, H.; McDonough, B.; White, W.

    1996-12-01

    The Geochemical Earth Reference Model (GERM) initiative is a grass- roots effort with the goal of establishing a community consensus on a chemical characterization of the Earth, its major reservoirs, and the fluxes between them. Long term goal of GERM is a chemical reservoir characterization analogous to the geophysical effort of the Preliminary Reference Earth Model (PREM). Chemical fluxes between reservoirs are included into GERM to illuminate the long-term chemical evolution of the Earth and to characterize the Earth as a dynamic chemical system. In turn, these fluxes control geological processes and influence hydrosphere-atmosphere-climate dynamics. While these long-term goals are clearly the focus of GERM, the process of establishing GERM itself is just as important as its ultimate goal. The GERM initiative is developed in an open community discussion on the World Wide Web (GERM home page is at http://www-ep.es.llnl. gov/germ/germ-home.html) that is mediated by a series of editors with responsibilities for distinct reservoirs and fluxes. Beginning with the original workshop in Lyons (March 1996) GERM is continued to be developed on the Internet, punctuated by workshops and special sessions at professional meetings. It is planned to complete the first model by mid-1997, followed by a call for papers for a February 1998 GERM conference in La Jolla, California.

  3. The role of APCDD1 in epithelial rearrangement in tooth morphogenesis.

    PubMed

    Neupane, Sanjiv; Sohn, Wern-Joo; Gwon, Gi-Jeong; Kim, Ki-Rim; Lee, Sanggyu; An, Chang-Hyeon; Suh, Jo-Young; Shin, Hong-In; Yamamoto, Hitoshi; Cho, Sung-Won; Lee, Youngkyun; Kim, Jae-Young

    2015-10-01

    Adenomatosis polyposis coli downregulated 1 (APCDD1), a negative regulator of Wnt signaling, was examined to understand detailed mechanisms underlying Wnt signaling tooth development. In situ hybridization showed that Apcdd1 was expressed in the condensed mesenchyme at the bud stage, and in the inner enamel epithelium (IEE), including enamel knot (EK) at the cap stage. In vitro organ cultivation by using Apcdd1 antisense oligodeoxynucleotides was performed at E13.5 for 2 days to define the developmental functions of APCDD1 during tooth development. Analysis of histogenesis and cellular events such as cell adhesion, proliferation, apoptosis and epithelial rearrangement after Apcdd1 knockdown showed altered morphogenesis of the tooth germ with decreased cell proliferation and altered localization of cell adhesion molecules. Actin filament staining and 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) labeling of IEE cells showed that Apcdd1 knockdown enhanced epithelial rearrangement in the IEE and EK. To understand the precise signaling regulations of Apcdd1, we evaluated the altered expression patterns of signaling molecules, related with Wnt and enamel knot signalings using RT-qPCR. Tooth germs at cap stage were transplanted into the kidney capsules and were allowed to develop into calcified teeth for 3 weeks. Apcdd1 knockdown increased the number of ectopic cusps on the mesial side of the tooth. Our results suggested that APCDD1 modulates the gene expression of Wnt- and EK-related signaling molecules at the cap stage of tooth development, and is involved in tooth cusp patterning by modulating the epithelial rearrangement in the IEE. PMID:26170146

  4. Transcription factor Sp3 is essential for post-natal survival and late tooth development

    PubMed Central

    Bouwman, Peter; Göllner, Heike; Elsässer, Hans-Peter; Eckhoff, Gabriele; Karis, Alar; Grosveld, Frank; Philipsen, Sjaak; Suske, Guntram

    2000-01-01

    Sp3 is a ubiquitously expressed transcription factor closely related to Sp1 (specificity protein 1). We have disrupted the mouse Sp3 gene by homologous recombination. Sp3-deficient embryos are growth retarded and invariably die at birth of respiratory failure. The cause for the observed breathing defect remains obscure since only minor morphological alterations were observed in the lung, and surfactant protein expression is indistinguishable from that in wild-type mice. Histological examinations of individual organs in Sp3–/– mice show a pronounced defect in late tooth formation. In Sp3 null mice, the dentin/enamel layer of the developing teeth is impaired due to the lack of ameloblast-specific gene products. Comparison of the Sp1 and Sp3 knockout phenotype shows that Sp1 and Sp3 have distinct functions in vivo, but also suggests a degree of functional redundancy. PMID:10675334

  5. Role of Osterix and MicroRNAs in Bone Formation and Tooth Development

    PubMed Central

    Wang, Chuan; Liao, Haiqing; Cao, Zhengguo

    2016-01-01

    Osterix (Osx) is an osteoblast-specific transcription factor that is essential for bone formation. MicroRNAs (miRNAs) are ~22-nucleotide-long noncoding RNAs that play important regulatory roles in animals and plants by targeting mRNAs for cleavage or translational repression. They can also control osteoblast-mediated bone formation and osteoclast-related bone remodeling. The vital roles of Osx and miRNAs during bone formation have been well studied, but very few studies have discussed their co-functions and the relationships between them. In this review, we outline the significant functions of Osx and miRNAs on certain cell types during osteogenesis and illustrate their roles during tooth development. More importantly, we discuss the relationship between Osx and miRNAs, which we believe could lead to a new treatment for skeletal and periodontal diseases. PMID:27543160

  6. The effects of periradicular inflamation and infection on a primary tooth and permanent successor.

    PubMed

    Cordeiro, Mabel Mariela Rodriguez; Rocha, Maria Jose de Carvalho

    2005-01-01

    Primary teeth and the permanent successors must be understood as interdependent units, where each one of them interacts with and depends on each other. Pulpal inflammation/infection of a primary tooth and the spread of this condition over the periradicular tissues can lead to alterations in the dental germ of the permanent successor and to the surrounding structures if no therapy is done, i.e. endodontics or extraction. This work will present cases of permanent teeth that showed alteration in eruption and / or in development, as a consequence of inflammation / infection of the preceding primary teeth, such as: hypoplasia, morphological alteration on the dental crown or total arrest of. radicular formation. The teeth analysed in this study belong to patients who attended the Universidade Federal de Santa Catarina Children's Dentistry Clinic. The earlier these lesions are diagnosed, the less were the destructive effects and the consequences on the primary tooth/permanent germ unit. PMID:15926433

  7. Wnt signaling during tooth replacement in zebrafish (Danio rerio): pitfalls and perspectives.

    PubMed

    Huysseune, Ann; Soenens, Mieke; Elderweirdt, Fien

    2014-01-01

    The canonical (β-catenin dependent) Wnt signaling pathway has emerged as a likely candidate for regulating tooth replacement in continuously renewing dentitions. So far, the involvement of canonical Wnt signaling has been experimentally demonstrated predominantly in amniotes. These studies tend to show stimulation of tooth formation by activation of the Wnt pathway, and inhibition of tooth formation when blocking the pathway. Here, we report a strong and dynamic expression of the soluble Wnt inhibitor dickkopf1 (dkk1) in developing zebrafish (Danio rerio) tooth germs, suggesting an active repression of Wnt signaling during morphogenesis and cytodifferentiation of a tooth, and derepression of Wnt signaling during start of replacement tooth formation. To further analyse the role of Wnt signaling, we used different gain-of-function approaches. These yielded disjunct results, yet none of them indicating enhanced tooth replacement. Thus, masterblind (mbl) mutants, defective in axin1, mimic overexpression of Wnt, but display a normally patterned dentition in which teeth are replaced at the appropriate times and positions. Activating the pathway with LiCl had variable outcomes, either resulting in the absence, or the delayed formation, of first-generation teeth, or yielding a regular dentition with normal replacement, but no supernumerary teeth or accelerated tooth replacement. The failure so far to influence tooth replacement in the zebrafish by perturbing Wnt signaling is discussed in the light of (i) potential technical pitfalls related to dose- or time-dependency, (ii) the complexity of the canonical Wnt pathway, and (iii) species-specific differences in the nature and activity of pathway components. Finally, we emphasize the importance of in-depth knowledge of the wild-type pattern for reliable interpretations. It is hoped that our analysis can be inspiring to critically assess and elucidate the role of Wnt signaling in tooth development in polyphyodonts. PMID

  8. Wnt signaling during tooth replacement in zebrafish (Danio rerio): pitfalls and perspectives

    PubMed Central

    Huysseune, Ann; Soenens, Mieke; Elderweirdt, Fien

    2014-01-01

    The canonical (β-catenin dependent) Wnt signaling pathway has emerged as a likely candidate for regulating tooth replacement in continuously renewing dentitions. So far, the involvement of canonical Wnt signaling has been experimentally demonstrated predominantly in amniotes. These studies tend to show stimulation of tooth formation by activation of the Wnt pathway, and inhibition of tooth formation when blocking the pathway. Here, we report a strong and dynamic expression of the soluble Wnt inhibitor dickkopf1 (dkk1) in developing zebrafish (Danio rerio) tooth germs, suggesting an active repression of Wnt signaling during morphogenesis and cytodifferentiation of a tooth, and derepression of Wnt signaling during start of replacement tooth formation. To further analyse the role of Wnt signaling, we used different gain-of-function approaches. These yielded disjunct results, yet none of them indicating enhanced tooth replacement. Thus, masterblind (mbl) mutants, defective in axin1, mimic overexpression of Wnt, but display a normally patterned dentition in which teeth are replaced at the appropriate times and positions. Activating the pathway with LiCl had variable outcomes, either resulting in the absence, or the delayed formation, of first-generation teeth, or yielding a regular dentition with normal replacement, but no supernumerary teeth or accelerated tooth replacement. The failure so far to influence tooth replacement in the zebrafish by perturbing Wnt signaling is discussed in the light of (i) potential technical pitfalls related to dose- or time-dependency, (ii) the complexity of the canonical Wnt pathway, and (iii) species-specific differences in the nature and activity of pathway components. Finally, we emphasize the importance of in-depth knowledge of the wild-type pattern for reliable interpretations. It is hoped that our analysis can be inspiring to critically assess and elucidate the role of Wnt signaling in tooth development in polyphyodonts. PMID

  9. [Tooth regeneration in the guinea pig (Cavia porcellus)].

    PubMed

    Stephan, F; Artis, J P; Lanot, R

    1977-01-01

    The first inferior molar has been extracted, a part of its being reimplanted or not. A new molar of normal form regenerated, apparently from the apex of the tooth germ, in all cases in which the alveolus was left free or implanted with a tooth freagment deprived of pulpa. PMID:145296

  10. SKAP, an outer kinetochore protein, is required for mouse germ cell development

    PubMed Central

    Grey, Corinne; Espeut, Julien; Ametsitsi, Rachel; Kumar, Rajeev; Luksza, Malgorzata; Brun, Christine; Verlhac, Marie-Hélene; Suja, José Angél; de Massy, Bernard

    2016-01-01

    In sexually reproducing organisms, accurate gametogenesis is crucial for the transmission of genetic material from one generation to the next. This requires the faithful segregation of chromosomes during mitotic and meiotic divisions. One of the main players in this process is the kinetochore, a large multi-protein complex that forms at the interface of centromeres and microtubules. Here, we analyzed the expression profile and function of small kinetochore-associated protein (SKAP) in the mouse. We found that two distinct SKAP isoforms are specifically expressed in the germline: a smaller isoform, which is detected in spermatogonia and spermatocytes and localized in the outer mitotic and meiotic kinetochores from metaphase to telophase, and a larger isoform, which is expressed in the cytoplasm of elongating spermatids. We generated SKAP-deficient mice and found that testis size and sperm production were severely reduced in mutant males. This phenotype was partially caused by defects during spermatogonia proliferation before entry into meiosis. We conclude that mouse SKAP, while being dispensable for somatic cell divisions, has an important role in the successful outcome of male gametogenesis. In germ cells, analogous to what has been suggested in studies using immortalized cells, SKAP most likely stabilizes the interaction between kinetochores and microtubules, where it might be needed as an extra safeguard to ensure the correct segregation of mitotic and meiotic chromosomes. PMID:26667018

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

    SciTech Connect

    Ishida, Kentaro; Murofushi, Mayumi; Nakao, Kazuhisa; Morita, Ritsuko; Ogawa, Miho; Tsuji, Takashi

    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 number 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.

  12. Role of Hertwig's epithelial root sheath cells in tooth root development.

    PubMed

    Zeichner-David, Margarita; Oishi, Keiji; Su, Zhengyan; Zakartchenko, Vassili; Chen, Li-Sha; Arzate, Higinio; Bringas, Pablo

    2003-12-01

    During tooth development, after the completion of crown formation, the apical mesenchyme forms the developing periodontium while the inner and outer enamel epithelia fuse below the level of the crown cervical margin to produce a bilayered epithelial sheath termed Hertwig's epithelial root sheath (HERS). The role of HERS cells in root formation is widely accepted; however, the precise function of these cells remains controversial. Functions suggested have ranged from structural (subdivide the dental ectomesenchymal tissues into dental papilla and dental follicle), regulators of timing of root development, inducers of mesenchymal cell differentiation into odontoblasts and cementoblasts, to cementoblast cell precursors. The characterization of the HERS phenotype has been hindered by the small amount of tissue present at a given time during root formation. In this study, we report the establishment of an immortal HERS-derived cell line that can be maintained in culture and then induced to differentiate in vitro. Characterization of the HERS phenotype using reverse transcriptase-polymerase chain reaction and Western blot immunostaining suggests that HERS cells initially synthesize and secrete some enamel-related proteins such as ameloblastin, and then these cells appear to change their morphology and produce a mineralized extracellular matrix resembling acellular cementum. These studies suggest that the acellular and cellular cementum are synthesized by two different types of cells, the first one by HERS-derived cementoblasts and the later by neural crest-derived cementoblasts. PMID:14648842

  13. Is tooth agenesis related to brainstem anomalies in myelomeningocele patients with Chiari II malformations?

    PubMed

    Linderström, Annelie; Samuelsson, Lars; Huggare, Jan

    2002-12-01

    Defects in the prenatal development of the brainstem can result in cranial nerve deficiencies. As the development of tooth germ is dependent on n. trigeminus, which originates from the brainstem, the hypothesis underlying this study was that anomalies of the brainstem would lead to an increased prevalence of tooth agenesis. Twenty-three patients (13 F and 10 M, age range 6-37 years) were studied, all with myclomeningocele and brainstem anomalies (Chiari II). They were examined retrospectively from the data in journals and dental radiographs and compared to available data on the prevalence of tooth agenesis in the Swedish population. Our hypothesis was rejected, since there was insignificant difference in the frequency of agenesis in our material (8.7%) compared with that of the Swedish population (7.4%). PMID:12512882

  14. Development of a Risk Stratification System to Guide Treatment for Female Germ Cell Tumors

    PubMed Central

    Meisel, Jane L.; Woo, Kaitlin M.; Sudarsan, Nora; Eng, Jana; Patil, Sujata; Jacobsen, Erin P.; Murali, Rajmohan; Gardner, Ginger J.; Bosl, George J.; Aghajanian, Carol; Feldman, Darren R.

    2016-01-01

    Objective Due to their rarity, little is known about prognostic factors in female germ cell tumors (GCTs) or outcomes following systemic therapy. Management is largely based on studies of male GCT and epithelial ovarian cancer. Methods Chart review was performed for all females with GCT seen at Memorial Sloan Kettering Cancer Center (MSKCC) from 1990 to 2012. Patients receiving chemotherapy were stratified using a modification of the male IGCCCG risk system, and the classifier was correlated with outcome. Results Of 93 patients, 92 (99%) underwent primary surgery and 85 (92%) received chemotherapy. Modified IGCCCG classification was significantly associated with progression-free survival (PFS) and overall survival (OS), both when applied preoperatively and pre-chemotherapy (p<0.001 for all four analyses). Progression after initial chemotherapy (n=29) was detected by imaging in 14 (48%) patients, by serum tumor markers in 6 (21%) patients, and by multiple methods in the rest. Seven (29%) of 24 patients treated with salvage chemotherapy achieved long-term PFS, including 4/6 who received high-dose chemotherapy (HDCT) as initial salvage versus 3/16 treated with other initial salvage regimens. The estimated 3-year OS rate was 84% (95% CI, 76-92%), with a trend favoring dysgerminoma over non-dysgerminoma histologies (p=0.12). Conclusions Modified IGCCCG classification was prognostic for female GCT patients in this cohort and identified a poor-risk group who may benefit from more intensive first-line chemotherapy. Both imaging and tumor marker evaluation were important in identifying relapses after first-line chemotherapy. The majority of long-term remissions with salvage therapy were achieved with initial salvage HDCT. PMID:26115974

  15. Lhx8 Mediated Wnt and TGFβ Pathways in Tooth Development and Regeneration

    PubMed Central

    Zhou, Chen; Yang, Guodong; Chen, Mo; Wang, Chenglin; He, Ling; Xiang, Lusai; Chen, Danying; Ling, Junqi; Mao, Jeremy J.

    2015-01-01

    LIM homeobox 8 (Lhx8) is a highly conserved transcriptional factor with recently illustrated roles in cholinergic and GABAergic differentiation, and is expressed in neural crest derived craniofacial tissues during development. However, Lhx8 functions and signaling pathways are largely elusive. Here we showed that Lhx8 regulates dental mesenchyme differentiation and function via Wnt and TGFβ pathways. Lhx8 expression was restricted to dental mesenchyme from E11.5 to a peak at E14.5, and absent in dental epithelium. By reconstituting dental epithelium and mesenchyme in an E16.5 tooth organ, Lhx8 knockdown accelerated dental mesenchyme differentiation; conversely, Lhx8 overexpression attenuated dentin formation. Lhx8 overexpressed adult human dental pulp stem/progenitor cells in β-tricalcium phosphate cubes attenuated mineralized matrix production in vivo. Gene profiling revealed that postnatal dental pulp stem/progenitor cells upon Lhx8 overexpression modified several matrix related gene expression including Dspp, Cola1 and osteocalcin. Lhx8 transcriptionally activates Wnt and TGFβ pathways, and its attenuation upregulates multiple dentinogenesis genes. Together, Lhx8 regulates dentin development and regeneration by fine-turning Wnt and TGFβ signaling. PMID:26081866

  16. Lhx8 mediated Wnt and TGFβ pathways in tooth development and regeneration.

    PubMed

    Zhou, Chen; Yang, Guodong; Chen, Mo; Wang, Chenglin; He, Ling; Xiang, Lusai; Chen, Danying; Ling, Junqi; Mao, Jeremy J

    2015-09-01

    LIM homeobox 8 (Lhx8) is a highly conserved transcriptional factor with recently illustrated roles in cholinergic and GABAergic differentiation, and is expressed in neural crest derived craniofacial tissues during development. However, Lhx8 functions and signaling pathways are largely elusive. Here we showed that Lhx8 regulates dental mesenchyme differentiation and function via Wnt and TGFβ pathways. Lhx8 expression was restricted to dental mesenchyme from E11.5 to a peak at E14.5, and absent in dental epithelium. By reconstituting dental epithelium and mesenchyme in an E16.5 tooth organ, Lhx8 knockdown accelerated dental mesenchyme differentiation; conversely, Lhx8 overexpression attenuated dentin formation. Lhx8 overexpressed adult human dental pulp stem/progenitor cells in β-tricalcium phosphate cubes attenuated mineralized matrix production in vivo. Gene profiling revealed that postnatal dental pulp stem/progenitor cells upon Lhx8 overexpression modified matrix related gene expression including Dspp, Cola1 and osteocalcin. Lhx8 transcriptionally activated Wnt and TGFβ pathways, and its attenuation upregulated multiple dentinogenesis genes. Together, Lhx8 regulates dentin development and regeneration by fine-turning Wnt and TGFβ signaling. PMID:26081866

  17. Development of mouse and rat oocytes in chimeric reaggregated ovaries after interspecific exchange of somatic and germ cell components.

    PubMed

    Eppig, J J; Wigglesworth, K

    2000-10-01

    The germ cell and somatic cell compartments of newborn rat and mouse ovaries, which contain only primordial stage follicles, were completely exchanged and reaggregated to produce xenogeneic chimeric ovaries. The reaggregated ovaries were grafted beneath the renal capsules of ovariectomized SCID mice to develop for periods up to 21 days. Xenogeneic follicles developed with essentially normal morphological characteristics. Both rat and mouse oocytes with species-specific characteristics grew within follicles that were composed of somatic cells exclusively of the alternative species. Rat oocytes grown in mouse follicles became competent to resume meiosis, and progressed to metaphase II when they were removed from follicles and cultured. In addition, mouse oocytes grown in rat follicles underwent fertilization and preimplantation development in vitro, and developed to term after embryos were transferred to pseudopregnant mouse foster mothers. Therefore, despite an estimated 11 million years of divergent evolution, oocytes and somatic cells of rat and mouse ovaries can be exchanged and can produce functional oocytes. It is concluded that factors involved in oocyte-somatic cell interactions necessary to support oocyte development and appropriate differentiation of the oocyte-associated granulosa cells are conserved between rats and mice. Moreover, although granulosa cells play important roles in oocyte development, the development of species-specific characteristics of oocytes occurs without apparent modification by a xenogeneic follicular environment. PMID:10993822

  18. Hedgehog signaling regulates dental papilla formation and tooth size during zebrafish odontogenesis

    PubMed Central

    Yu, Jeffrey C.; Fox, Zachary D.B.; Crimp, James L.; Littleford, Hana E.; Jowdry, Andrea L.; Jackman, William R.

    2015-01-01

    Background Intercellular communication by the hedgehog cell signaling pathway is necessary for tooth development throughout the vertebrates, but it remains unclear which specific developmental signals control cell behavior at different stages of odontogenesis. To address this issue, we have manipulated hedgehog activity during zebrafish tooth development and visualized the results using confocal microscopy. Results We first established that reporter lines for dlx2b, fli1, NF-κB, and prdm1a are markers for specific subsets of tooth germ tissues. We then blocked hedgehog signaling with cyclopamine and observed a reduction or elimination of the cranial neural crest derived dental papilla, which normally contains the cells that later give rise to dentin-producing odontoblasts. Upon further investigation we observed that the dental papilla begins to form and then regresses in the absence of hedgehog signaling, through a mechanism unrelated to cell proliferation or apoptosis. We also found evidence of an isometric reduction in tooth size that correlates with the time of earliest hedgehog inhibition. Conclusions We hypothesize that these results reveal a previously uncharacterized function of hedgehog signaling during tooth morphogenesis, regulating the number of cells in the dental papilla and thereby controlling tooth size. PMID:25645398

  19. Tooth extraction

    MedlinePlus

    ... hole where the tooth was, causing bleeding and pain. This is called dry socket. To care for your mouth: Begin gently brushing and flossing your other teeth the day after your surgery. Avoid the area near the open ...

  20. Tooth Problems

    MedlinePlus

    ... to determine if you need to see your dentist right away. SYMPTOMS DIAGNOSIS SELF-CARE Begin Here ... You have TOOTH LOSS. DENTAL EMERGENCY See your dentist or go to the emergency room right away. ...

  1. [Tooth-pick? Picking the Right Tooth].

    PubMed

    Apicella, Lysann; Cassis, Paola Rodoni; Balestra, Brenno

    2016-01-20

    We report about an 80-year-old patient, who underwent the extraction of an upper molar tooth because of facial pain. In the course of time the patient developed a maxillary sinusitis in presence of an ectopic tooth. Given that the patient got fever, neck pain and -stiffness, a purulent meningitis was first suspected. The liquor analysis was normal and the CT-scan showed a calcification around the dens axis. We finally diagnosed a “Crowned Dens”-syndrome. PMID:26787332

  2. Tools for the genetic analysis of germ cells.

    PubMed

    Hammond, Shirley S; Matin, Angabin

    2009-09-01

    Germ cells are essential for the propagation of individual species. Studies on germ cell development in mice highlight important biological paradigms. Beginning with their first appearance around embryonic day 7 (E7), germ cells undergo specific cellular changes at different stages of their embryonic and adult development. Germ cells migrate through the hind-regions of the embryo to eventually home into the developing gonads. Further differentiation and development of germ cells differ in males and females. The processes involved in germ cell development and their eventual differentiation into sperm and oocytes have been under extensive investigation in recent years. Studies on germ cells have shed light on the cellular and molecular processes involved in their specification, migration, proliferation, death, and differentiation. These studies have also revealed much about maintenance of stem cell populations and fertility. Here we review the genetic tools that are at present available to study germ cells in the mouse. PMID:19548313

  3. Interaction between Fibronectin and β1 Integrin Is Essential for Tooth Development

    PubMed Central

    Yamada, Aya; Yuasa, Kenji; Yoshizaki, Keigo; Iwamoto, Tsutomu; Saito, Masahiro; Nakamura, Takashi; Fukumoto, Satoshi

    2015-01-01

    The dental epithelium and extracellular matrix interact to ensure that cell growth and differentiation lead to the formation of teeth of appropriate size and quality. To determine the role of fibronectin in differentiation of the dental epithelium and tooth formation, we analyzed its expression in developing incisors. Fibronectin mRNA was expressed during the presecretory stage in developing dental epithelium, decreased in the secretory and early maturation stages, and then reappeared during the late maturation stage. The binding of dental epithelial cells derived from postnatal day-1 molars to a fibronectin-coated dish was inhibited by the RGD but not RAD peptide, and by a β1 integrin-neutralizing antibody, suggesting that fibronectin-β1 integrin interactions contribute to dental epithelial-cell binding. Because fibronectin and β1 integrin are highly expressed in the dental mesenchyme, it is difficult to determine precisely how their interactions influence dental epithelial differentiation in vivo. Therefore, we analyzed β1 integrin conditional knockout mice (Intβ1lox-/lox-/K14-Cre) and found that they exhibited partial enamel hypoplasia, and delayed eruption of molars and differentiation of ameloblasts, but not of odontoblasts. Furthermore, a cyst-like structure was observed during late ameloblast maturation. Dental epithelial cells from knockout mice did not bind to fibronectin, and induction of ameloblastin expression in these cells by neurotrophic factor-4 was inhibited by treatment with RGD peptide or a fibronectin siRNA, suggesting that the epithelial interaction between fibronectin and β1 integrin is important for ameloblast differentiation and enamel formation. PMID:25830530

  4. Inhibition of NOS-NO System Prevents Autoimmune Orchitis Development in Rats: Relevance of NO Released by Testicular Macrophages in Germ Cell Apoptosis and Testosterone Secretion

    PubMed Central

    Jarazo Dietrich, Sabrina; Fass, Mónica Irina; Jacobo, Patricia Verónica; Sobarzo, Cristian Marcelo Alejandro; Lustig, Livia; Theas, María Susana

    2015-01-01

    Background Although the testis is considered an immunoprivileged organ it can orchestrate immune responses against pathological insults such as infection and trauma. Experimental autoimmune orchitis (EAO) is a model of chronic inflammation whose main histopathological features it shares with human orchitis. In EAO an increased number of macrophages infiltrate the interstitium concomitantly with progressive germ cell degeneration and impaired steroidogenesis. Up-regulation of nitric oxide (NO)-NO synthase (NOS) system occurs, macrophages being the main producers of NO. Objective The aim of our study was to evaluate the role of NO-NOS system in orchitis development and determine the involvement of NO released by testicular macrophages on germ cell apoptosis and testosterone secretion. Method and Results EAO was induced in rats by immunization with testicular homogenate and adjuvants (E group) and a group of untreated normal rats (N) was also studied. Blockage of NOS by i.p. injection of E rats with a competitive inhibitor of NOS, L-NAME (8mg/kg), significantly reduced the incidence and severity of orchitis and lowered testicular nitrite content. L-NAME reduced germ cell apoptosis and restored intratesticular testosterone levels, without variations in serum LH. Co-culture of N testicular fragments with testicular macrophages obtained from EAO rats significantly increased germ cell apoptosis and testosterone secretion, whereas addition of L-NAME lowered both effects and reduced nitrite content. Incubation of testicular fragments from N rats with a NO donor DETA-NOnoate (DETA-NO) induced germ cell apoptosis through external and internal apoptotic pathways, an effect prevented by N-acetyl-L-cysteine (NAC). DETA-NO inhibited testosterone released from Leydig cells, whereas NAC (from 2.5 to 15 mM) did not prevent this effect. Conclusions We demonstrated that NO-NOS system is involved in the impairment of testicular function in orchitis. NO secreted mainly by testicular

  5. GERM as a tool for space station documentation

    NASA Technical Reports Server (NTRS)

    Crouse, Ken; Hardwick, Charles

    1990-01-01

    GERM as a tool for space station documentation is presented in the form of viewgraphs. The following subject areas are covered: problem statement, hypermedia as a tool for documentation, description of GERM, technical approach, application development, and results and conclusions.

  6. Recommendations to enable drug development for inherited neuropathies: Charcot-Marie-Tooth and Giant Axonal Neuropathy

    PubMed Central

    Sames, Lori; Moore, Allison; Arnold, Renee; Ekins, Sean

    2014-01-01

    Approximately 1 in 2500 Americans suffer from Charcot-Marie-Tooth (CMT) disease. The underlying disease mechanisms are unique in most forms of CMT, with many point mutations on various genes causing a toxic accumulation of misfolded proteins. Symptoms of the disease often present within the first two decades of life, with CMT1A patients having reduced compound muscle and sensory action potentials, slow nerve conduction velocities, sensory loss, progressive distal weakness, foot and hand deformities, decreased reflexes, bilateral foot drop and about 5% become wheelchair bound. In contrast, the ultra-rare disease Giant Axonal Neuropathy (GAN) is frequently described as a recessively inherited condition that results in progressive nerve death. GAN usually appears in early childhood and progresses slowly as neuronal injury becomes more severe and leads to death in the second or third decade. There are currently no treatments for any of the forms of CMTs or GAN. We suggest that further clinical studies should analyse electrical impedance myography as an outcome measure for CMT. Further, additional quality of life (QoL) assessments for these CMTs are required, and we need to identify GAN biomarkers as well as develop new genetic testing panels for both diseases. We propose that using the Global Registry of Inherited Neuropathy (GRIN) could be useful for many of these studies. Patient advocacy groups and professional organizations (such as the Hereditary Neuropathy Foundation (HNF), Hannah's Hope Fund (HHF), The Neuropathy Association (TNA) and the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM) can play a central role in educating clinicians and patients. Undertaking these studies will assist in the correct diagnosis of disease recruiting patients for clinical studies, and will ultimately improve the endpoints for clinical trials. By addressing obstacles that prevent industry investment in various forms of inherited neuropathies, we can

  7. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... from many different conditions. Specific diseases can affect tooth shape, tooth color, time of appearance, or absence ...

  8. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

  9. Development of a new approach for targeted gene editing in primordial germ cells using TALENs in Xenopus

    PubMed Central

    Nakajima, Keisuke; Yaoita, Yoshio

    2015-01-01

    ABSTRACT A gene of interest can be efficiently modified using transcription activator-like effector nucleases (TALENs) (Christian et al., 2010;Li et al., 2011). However, if a target gene is essential for development, growth and fertility, use of TALENs with high mutagenic activity in F0 frogs could result in developmental disorders or sterility, which would reduce the number of F1 progeny and make F1 phenotypical analysis difficult. We used the 3′ untranslated region of DEADSouth gene (DS-3′) of Xenopus tropicalis to solve this problem, because the addition of the DS-3′ to mRNA is known to induce primordial germ cell (PGC)-specific expression and reduce the stability in somatic cells of mRNA in Xenopus laevis. At first, we inserted the X. tropicalis DS-3′ downstream of the EGFP termination codon and confirmed that the EGFP expression was specifically detected in PGCs for three weeks. Therefore, we inserted the DS-3′ downstream of the termination codon of the TALEN coding sequence. The tyrosinase gene was selected as the target gene for TALEN because the bi-allelic mutation of this gene is easily discernible by the albino phenotype. When fertilized eggs were microinjected with TALEN mRNAs fused to the DS-3′, their sperm and oocytes had a high rate (84–100%) of target-gene modification in contrast to the lower rate (0–45%) of nucleotide alteration observed in somatic cells. PMID:25661867

  10. Development and prospects of organ replacement regenerative therapy.

    PubMed

    Hirayama, Masatoshi; Oshima, Masamitsu; Tsuji, Takashi

    2013-11-01

    Current approaches for the development of regenerative therapies have been influenced by our understanding of embryonic development, stem cell biology, and tissue engineering technology. The ultimate goal of regenerative therapy is to develop fully functioning bioengineered organs to replace lost or damaged organs that result from disease, injury, or aging. Almost all organs including ectodermal organs, such as teeth, hair, salivary glands, and lacrimal glands, arise from organ germs induced by reciprocal epithelial-mesenchymal interactions in the developing embryo. A novel concept to generate a bioengineered organ is to recreate organogenesis and thereby develop fully functioning bioengineered organs from the resulting bioengineered organ germ generated via 3-dimensional cell manipulation using immature stem cells in vitro. We have previously developed a bioengineering method for forming a 3-dimensional organ germ in the early developmental stages, termed the "bioengineered organ germ method." Recently, we reported fully functioning bioengineered tooth replacements after transplantation of a bioengineered tooth germ or a mature tooth unit comprising the bioengineered tooth and periodontal tissues. This concept could be adopted to generate not only teeth but also bioengineered hair follicles, salivary glands, and lacrimal glands. These studies emphasize the potential for bioengineered organ replacement in future regenerative therapies. In this review, we will summarize the strategies and the recent progress of research and development for the establishment of organ replacement regenerative therapies. PMID:24104927

  11. Development and implementation of the Clinical Tooth Shade Differentiation Course – an evaluation over 3 years

    PubMed Central

    Olms, Constanze; Haak, Rainer; Jakstat, Holger A.

    2016-01-01

    Objective: Tooth shade differentiation concerns the identification and classification of tooth shades. The objective of this project was to implement the Clinical Tooth Shade Differentiation Course in the preclinical stage of studies and to evaluate the students' perspective over a period of 3 years. Methodology: The course is planned for a duration of 10 weeks with two 45-minute sessions per semester week. The entire attendance time was 10:15 h. 2 lectures of 90 minutes each, 2 seminars of 60 min each and 2 teaching units with the phantom head and role playing took place. In addition to the various parameters of tooth shade, changes in tooth shade and the basics of dental esthetics, clinical procedures for manual and digital tooth shade determination were explained and practiced. 96% (69 of 72) of the students participated in the first evaluation in 2012/2013 (T1), and 68% of these were women. In the following year, 2013/2014 (T2), 92% (45 of 48 students) took part; 62% of these were women and 38% men. The 2014/2015 evaluation (T3) comprised 94% (45 of 48 students). Of these, 67% were women. Results: In the evaluation, the students gave the course a positive grade. The questions in "General/Organization" were given a mean (M) of 1.5 (SD=0.7) in T1 and T2 , and 1.2 (SD=0.3) in T3. The "Overall Assessment" yielded MT1=1.6 (SD=0.6), MT2=1.5 (SD=0.5) and MT3=1.1 (SD=0.3). In T1 and T2, the item "The instructor actively involved the students in the course" was given a mean of 2.1 (SD=0.9), and in T3 a mean of 1.2 (SD=0.5). Conclusions: The course presented here conceptually shows how practical dental skills can be taught in a theoretical and clinical context. Educational objectives from the role of a dental expert were taken from the national competence-based catalog of educational objectives for dentistry and can also be supplemented. The objectives can be transferred to other dental faculties. PMID:26958650

  12. Tooth - abnormal colors

    MedlinePlus

    ... things can cause tooth discoloration. The change in color may affect the entire tooth, or appear as spots or ... the tooth enamel. Your genes affect your tooth color. Other things ... include: Congenital diseases Environmental factors Infections ...

  13. Tooth Decay

    MedlinePlus

    ... decay starts in the outer layer, called the enamel. Without a filling, the decay can get deep into the tooth and its nerves and cause a toothache or abscess. To help prevent cavities Brush your teeth every day with a fluoride toothpaste Clean between ...

  14. Impacted tooth

    MedlinePlus

    ... Unerupted tooth References Buttaravoli P, Leffler SM, eds. Dental pain, pericoronitis. Minor Emergencies . 3rd ed. Philadelphia, PA: Elsevier Mosby; 2012:chap 46. Read More Abscess ... Updated by: Ilona Fotek, DMD, MS, Palm Beach Prosthodontics Dental Associates, West Palm Beach, FL. Review provided by ...

  15. Extraction and demulsification of oil from wheat germ, barley germ, and rice bran using an aqueous enzymatic method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An aqueous enzymatic method was developed to extract oil from wheat germ. The parameters that influence oil yield were investigated, including wheat germ pretreatment, comparison of various industrial enzymes, pH, ratio of wheat germ to water, reaction time and demulsification. Pretreatment at 180ºC...

  16. Coordination of Cellular Dynamics Contributes to Tooth Epithelium Deformations.

    PubMed

    Morita, Ritsuko; Kihira, Miho; Nakatsu, Yousuke; Nomoto, Yohei; Ogawa, Miho; Ohashi, Kazumasa; Mizuno, Kensaku; Tachikawa, Tetsuhiko; Ishimoto, Yukitaka; Morishita, Yoshihiro; Tsuji, Takashi

    2016-01-01

    The morphologies of ectodermal organs are shaped by appropriate combinations of several deformation modes, such as invagination and anisotropic tissue elongation. However, how multicellular dynamics are coordinated during deformation processes remains to be elucidated. Here, we developed a four-dimensional (4D) analysis system for tracking cell movement and division at a single-cell resolution in developing tooth epithelium. The expression patterns of a Fucci probe clarified the region- and stage-specific cell cycle patterns within the tooth germ, which were in good agreement with the pattern of the volume growth rate estimated from tissue-level deformation analysis. Cellular motility was higher in the regions with higher growth rates, while the mitotic orientation was significantly biased along the direction of tissue elongation in the epithelium. Further, these spatio-temporal patterns of cellular dynamics and tissue-level deformation were highly correlated with that of the activity of cofilin, which is an actin depolymerization factor, suggesting that the coordination of cellular dynamics via actin remodeling plays an important role in tooth epithelial morphogenesis. Our system enhances the understanding of how cellular behaviors are coordinated during ectodermal organogenesis, which cannot be observed from histological analyses. PMID:27588418

  17. Continued research on gin saw tooth design

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toothed saws have been used to separate cotton fiber from the seed for over 200 years. There have been many saw tooth designs developed over the years. Most of these designs were developed by trial and error. A complete and scientific analysis of tooth design has never been published. It is not know...

  18. Interplay Between MMP-9 and TIMP-2 Regulates Ameloblastoma Behavior and Tooth Morphogenesis.

    PubMed

    Nunia, Kalpana; Urs, Aadithya B; Kumar, Priya

    2016-01-01

    Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) have been implicated in the local invasiveness of ameloblastoma. This study aims to assess the role of MMP-9 and TIMP-2 in regulating tumor progression in ameloblastomas, taking tooth germs as control. Formalin-fixed, paraffin-embedded tissue sections of 4 tooth germs and 32 ameloblastomas were immunohistochemically examined using antibodies against MMP-9 and TIMP-2. Strong MMP-9 positivity was seen in the epithelial component in both controls and solid multicystic ameloblastoma. Statistically significant difference was observed in the mean stromal MMP-9 immunoscores between follicular, acanthomatous, and granular ameloblastoma when compared with the tooth germ (P=0.004). TIMP-2 expression in the epithelial and mesenchymal components of solid multicystic ameloblastoma and tooth germ was weak as compared with MMP-9 expression. Highest mean epithelial TIMP-2 immunoscore was observed in follicular ameloblastoma and the difference was statistically significant between follicular and granular ameloblastoma (P=0.05). The comparison of mean stromal TIMP-2 immunoscores showed statistically significant difference between follicular subtype and tooth germ (P=0.048), with tooth germ showing least expression among the groups studied. Strong stromal expression of MMP-9 in ameloblastoma compared with tooth germ mesenchyme indicated the possibility of tumor induction with release of growth factors and cytokines, resulting in invasiveness of ameloblastoma. Epithelial TIMP-2 expression was associated with the least and most aggressive behavior of follicular and granular cell ameloblastoma, respectively. Stromal TIMP-2 expression reflected its role in regulating tumor progression in ameloblastoma and in regulating developmental processes in tooth germs by their inhibitory effect on MMP-9. PMID:26067137

  19. Sonic hedgehog signalling inhibits palatogenesis and arrests tooth development in a mouse model of the nevoid basal cell carcinoma syndrome.

    PubMed

    Cobourne, Martyn T; Xavier, Guilherme M; Depew, Michael; Hagan, Louise; Sealby, Jane; Webster, Zoe; Sharpe, Paul T

    2009-07-01

    Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant or spontaneous disorder characterized by multiple cutaneous basal cell carcinomas, odontogenic keratocysts, skeletal anomalies and facial dysmorphology, including cleft lip and palate. Causative mutations for NBCCS occur in the PTCH1 gene on chromosome 9q22.3-q31, which encodes the principle receptor for the Hedgehog signalling pathway. We have investigated the molecular basis of craniofacial defects seen in NBCCS using a transgenic mouse model expressing Shh in basal epithelium under a Keratin-14 promoter. These mice have an absence of flat bones within the skull vault, hypertelorism, open-bite malocclusion, cleft palate and arrested tooth development. Significantly, increased Hedgehog signal transduction in these mice can influence cell fate within the craniofacial region. In medial edge epithelium of the palate, Shh activity prevents apoptosis and subsequent palatal shelf fusion. In contrast, high levels of Shh in odontogenic epithelium arrests tooth development at the bud stage, secondary to a lack of cell proliferation in this region. These findings illustrate the importance of appropriately regulated Hedgehog signalling during early craniofacial development and demonstrate that oro-facial clefting and hypodontia seen in NBCCS can occur as a direct consequence of increased Shh signal activity within embryonic epithelial tissues. PMID:19394325

  20. Tooth patterning and evolution.

    PubMed

    Salazar-Ciudad, Isaac

    2012-12-01

    Teeth are a good system for studying development and evolution. Tooth development is largely independent of the rest of the body and teeth can be grown in culture to attain almost normal morphology. Their development is not affected by the patterns of movement or sensorial perception in the embryo. Teeth are hard and easily preserved. Thus, there is plenty of easily accessible information about the patterns of morphological variation occurring between and within species. This review summarises recent work and describes how tooth development can be understood as the coupling between a reaction-diffusion system and differential growth produced by diffusible growth factors: which growth factors are involved, how they affect each other's expression and how they affect the spatial patterns of proliferation that lead to final morphology. There are some aspects of tooth development, however, that do not conform to some common assumptions in many reaction-diffusion models. Those are discussed here since they provide clues about how reaction-diffusion systems may work in actual developmental systems. Mathematical models implementing what we know about tooth development are discussed. PMID:23266218

  1. Expression profile of critical genes involved in FGF signaling pathway in the developing human primary dentition.

    PubMed

    Huang, Feng; Hu, Xiaoxiao; Fang, Chunni; Liu, Hong; Lin, Chensheng; Zhang, Yanding; Hu, Xuefeng

    2015-11-01

    Mammalian tooth development is regulated by paracrine signal molecules of several conserved family interactions between epithelium and mesenchyme. The expression patterns and regulative roles of FGF signaling have been extensively studied in the mouse odontogenesis; however, that is not well known in human tooth development. In order to unveil the molecular mechanisms that regulate human tooth morphogenesis, we examined the expression patterns of the critical molecules involved in FGF signaling pathway in the developing human tooth germ by in situ hybridization, immunohistochemistry, and real-time RT-PCR, including FGF ligands, receptors, and intracellular transducer. We found overlapping but distinct expression pattern of FGF ligands and receptors in the different stages and components. Expression of FGF4, FGF7, FGF8, and FGF9 persists widespread in human tooth mesenchyme, which is quite different to that of in mouse. FGFR1 may be the major receptor in regulate mechanisms of FGF signals in human tooth development. Real-time RT-PCR indeed confirmed the results of in situ hybridization. Results of K-Ras, p-ERK1/2, p-p38, p-JNK, and p-PDK1 expression reveal spatial and temporal patterns of FGF signaling during morphogenesis and organogenesis of human tooth germ. Activity of the FGF signaling transducer protein in human tooth germ was much higher than that of in mouse. Our results provided important FGF singling information in the developing process, pinpoint to the domains where the downstream target genes of FGF signaling can be sought, and enlightened our knowledge about the nature of FGF signaling in human tooth germ. PMID:26266341

  2. dead end, a novel vertebrate germ plasm component, is required for zebrafish primordial germ cell migration and survival.

    PubMed

    Weidinger, Gilbert; Stebler, Jürg; Slanchev, Krasimir; Dumstrei, Karin; Wise, Clare; Lovell-Badge, Robin; Thisse, Christine; Thisse, Bernard; Raz, Erez

    2003-08-19

    In most animals, primordial germ cell (PGC) specification and development depend on maternally provided cytoplasmic determinants that constitute the so-called germ plasm. Little is known about the role of germ plasm in vertebrate germ cell development, and its molecular mode of action remains elusive. While PGC specification in mammals occurs via different mechanisms, several germ plasm components required for early PGC development in lower organisms are expressed in mammalian germ cells after their migration to the gonad and are involved in gametogenesis. Here we show that the RNA of dead end, encoding a novel putative RNA binding protein, is a component of the germ plasm in zebrafish and is specifically expressed in PGCs throughout embryogenesis; Dead End protein is localized to perinuclear germ granules within PGCs. Knockdown of dead end blocks confinement of PGCs to the deep blastoderm shortly after their specification and results in failure of PGCs to exhibit motile behavior and to actively migrate thereafter. PGCs subsequently die, while somatic development is not effected. We have identified dead end orthologs in other vertebrates including Xenopus, mouse, and chick, where they are expressed in germ plasm and germ-line cells, suggesting a role in germ-line development in these organisms as well. PMID:12932328

  3. Biology of tooth replacement in amniotes

    PubMed Central

    Whitlock, John A; Richman, Joy M

    2013-01-01

    Tooth replacement is a common trait to most vertebrates, including mammals. Mammals, however, have lost the capacity for continuous tooth renewal seen in most other vertebrates, and typically have only 1–2 generations of teeth. Here, we review the mechanisms of tooth replacement in reptiles and mammals, and discuss in detail the current and historical theories on control of timing and pattern of tooth replacement and development. PMID:23788284

  4. Migratory ability of gonadal germ cells (GGCs) isolated from Ciconia boyciana and Geronticus eremita embryos into the gonad of developing chicken embryos

    PubMed Central

    NAKAJIMA, Yuki; FUKUDA, Haruka; ONUMA, Manabu; MURATA, Koichi; UEDA, Miya; SUNAGA, Emi; SHIRAISHI, Toshirou; TAJIMA, Atsushi

    2016-01-01

    We conducted experiments to evaluate the ability of gonadal germ cells (GGCs), isolated from the embryonic gonads of Ciconia boyciana or Geronticus eremita, to migrate into the gonads of developing chicken embryos. Fluorescently labeled GGCs, isolated by the PBS (−) method, were transferred into the dorsal aorta of 2-day-old chicken embryos. Five days after transfer, fluorescent GGCs were detected in the gonads of recipient embryos. Our results indicate that GGCs from Ciconia boyciana and Geronticus eremita are capable of migrating into the gonads of developing chicken embryos. PMID:26922915

  5. Specification of germ cell fate in mice.

    PubMed Central

    Saitou, Mitinori; Payer, Bernhard; Lange, Ulrike C; Erhardt, Sylvia; Barton, Sheila C; Surani, M Azim

    2003-01-01

    An early fundamental event during development is the segregation of germ cells from somatic cells. In many organisms, this is accomplished by the inheritance of preformed germ plasm, which apparently imposes transcriptional repression to prevent somatic cell fate. However, in mammals, pluripotent epiblast cells acquire germ cell fate in response to signalling molecules. We have used single cell analysis to study how epiblast cells acquire germ cell competence and undergo specification. Germ cell competent cells express Fragilis and initially progress towards a somatic mesodermal fate. However, a subset of these cells, the future primordial germ cells (PGCs), then shows rapid upregulation of Fragilis with concomitant transcriptional repression of a number of genes, including Hox and Smad genes. This repression may be a key event associated with germ cell specification. Furthermore, PGCs express Stella and other genes, such as Oct-4 that are associated with pluripotency. While these molecules are also detected in mature oocytes as maternally inherited factors, their early role is to regulate development and maintain pluripotency, and they do not serve the role of classical germline determinants. PMID:14511483

  6. Smad4-Shh-Nfic Signaling Cascade–Mediated Epithelial-Mesenchymal Interaction Is Crucial in Regulating Tooth Root Development

    PubMed Central

    Huang, Xiaofeng; Xu, Xun; Bringas, Pablo; Hung, Yee Ping; Chai, Yang

    2010-01-01

    Transforming growth factor β (TGF-β)/bone morphogenetic protein (BMP) signaling is crucial for regulating epithelial-mesenchymal interaction during organogenesis, and the canonical Smad pathway–mediated TGF-β/BMP signaling plays important roles during development and disease. During tooth development, dental epithelial cells, known as Hertwig's epithelial root sheath (HERS), participate in root formation following crown development. However, the functional significance of HERS in regulating root development remains unknown. In this study we investigated the signaling mechanism of Smad4, the common Smad for TGF-β/BMP signaling, in HERS in regulating root development. Tissue-specific inactivation of Smad4 in HERS results in abnormal enamel and dentin formation in K14-Cre;Smad4fl/fl mice. HERS enlarges but cannot elongate to guide root development without Smad4. At the molecular level, Smad4-mediated TGF-β/BMP signaling is required for Shh expression in HERS and Nfic (nuclear factor Ic) expression in the cranial neural crest (CNC)-derived dental mesenchyme. Nfic is crucial for root development, and loss of Nfic results in a CNC-derived dentin defect similar to the one of K14-Cre;Smad4fl/fl mice. Significantly, we show that ectopic Shh induces Nfic expression in dental mesenchyme and partially rescues root development in K14-Cre;Smad4fl/fl mice. Taken together, our study has revealed an important signaling mechanism in which TGF-β/BMP signaling relies on a Smad-dependent mechanism in regulating Nfic expression via Shh signaling to control root development. The interaction between HERS and the CNC-derived dental mesenchyme may guide the size, shape, and number of tooth roots. © 2010 American Society for Bone and Mineral Research. PMID:19888897

  7. Pneumomediastinum after Tooth Extraction

    PubMed Central

    Ocakcioglu, Ilhan; Koyuncu, Serhat; Kupeli, Mustafa; Bol, Oguzhan

    2016-01-01

    Pneumomediastinum is defined as the presence of air in mediastinum. Pneumomediastinum can sometimes occur after surgery. Pneumomediastinum seen after dental procedures is rare. We presented the case of subcutaneous emphysema developed in the neck and upper chest after tooth extraction and discussed the possible mechanisms of pneumomediastinum. PMID:26989552

  8. Pneumomediastinum after Tooth Extraction.

    PubMed

    Ocakcioglu, Ilhan; Koyuncu, Serhat; Kupeli, Mustafa; Bol, Oguzhan

    2016-01-01

    Pneumomediastinum is defined as the presence of air in mediastinum. Pneumomediastinum can sometimes occur after surgery. Pneumomediastinum seen after dental procedures is rare. We presented the case of subcutaneous emphysema developed in the neck and upper chest after tooth extraction and discussed the possible mechanisms of pneumomediastinum. PMID:26989552

  9. Development and microstructure of tooth histotypes in the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae) and the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae).

    PubMed

    Moyer, Joshua K; Riccio, Mark L; Bemis, William E

    2015-07-01

    Elasmobranchs exhibit two distinct arrangements of mineralized tissues in the teeth that are known as orthodont and osteodont histotypes. Traditionally, it has been said that orthodont teeth maintain a pulp cavity throughout tooth development whereas osteodont teeth are filled with osteodentine and lack a pulp cavity when fully developed. We used light microscopy, scanning electron microscopy, and high-resolution micro-computed tomography to compare the structure and development of elasmobranch teeth representing the two histotypes. As an example of the orthodont histotype, we studied teeth of the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae). For the osteodont histotype, we studied teeth of the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae). We document similarities and differences in tooth development and the microstructure of tissues in these two species and review the history of definitions and interpretations of elasmobranch tooth histotypes. We discuss a possible correlation between tooth histotype and tooth replacement and review the history of histotype differentiation in sharks. We find that contrary to a long held misconception, there is no orthodentine in the osteodont teeth of C. carcharias. PMID:25845614

  10. Orthodontic Tooth Movement: A Historic Prospective.

    PubMed

    Will, Leslie A

    2016-01-01

    The earliest report on orthodontic tooth movement in the English literature was published in 1911. Oppenheim carried out studies on baboons to determine what histologic changes occurred during tooth movement. Reitan and many others carried out research into the nature of tooth movement. The pressure-tension model of tooth movement developed from these studies, whereby the two sides of the tooth responded to forces as if in isolation. A second theory, proposed by Stuteville in 1938, was the hydraulic theory of tooth movement. In this theory, fluid from the vasculature, lymphatic system and intercellular spaces responds to the forces of tooth movement, damping the force and limiting movement. Bien and Baumrind expanded on this theory with their own studies in the 1960s. It is clear that both the pressure-tension and fluid flow concepts have merit, but considerable work needs to be done to ascertain the details so that tooth movement can be managed and controlled. PMID:26599117

  11. The pattern of histogenesis and growth of tooth plates in larval stages of extant lungfish.

    PubMed Central

    Smith, M M

    1985-01-01

    Comparison of new data obtained in this study on Protopterus aethiopicus with that published on Protopterus aethiopicus and Neoceratodus forsteri has confirmed the suggestion that the pattern of histogenesis of tooth plates in the early larval stages is very similar in the two genera. These similarities are more apparent both when a common terminology is adopted, based on a topogenic classification, and when the fundamental assumption is made that a single morphogenetic system operates for all odontodes. The model to explain the structure of all vertebrate dentitions with separate teeth in single or multiple tooth rows has been found to apply to dipnoan dentitions with fused teeth in a composite tooth plate. In this model, the epithelial invagination surrounding the margins of the tooth plate represents the dental lamina and, where this is in contact with mesenchymal cells, cell clusters (protogerms) arise. From these protogerms new odontodes (teeth) may develop if factors to inhibit differentiation are not present. Sites for initiation of odontodes become restricted to the labial margins of existing ridges on the tooth plate. Experimental studies on mammalian tooth germs are discussed and a model proposed for control of odontogenesis and histogenesis in dipnoan dentitions. Patterns of growth of hypermineralised petrodentine have been analysed and shown to depend initially on the arrangement of odontodes, and subsequently upon the ability of special cells in the pulp to generate new and wider layers of petrodentine. The initial pattern of petrodentine depends upon the position of odontodes in the forming ridges of the tooth plate. Subsequent patterns of petrodentine depend upon the extent of replacement growth beneath the tritural surface. Specialised cells, petroblasts, secrete the petrodentine within a shell of dentine. These cells differentiate from cells of the dental papilla after odontoblasts have begun to form dentine. They are regarded as a unique type of

  12. The pattern of histogenesis and growth of tooth plates in larval stages of extant lungfish.

    PubMed

    Smith, M M

    1985-06-01

    Comparison of new data obtained in this study on Protopterus aethiopicus with that published on Protopterus aethiopicus and Neoceratodus forsteri has confirmed the suggestion that the pattern of histogenesis of tooth plates in the early larval stages is very similar in the two genera. These similarities are more apparent both when a common terminology is adopted, based on a topogenic classification, and when the fundamental assumption is made that a single morphogenetic system operates for all odontodes. The model to explain the structure of all vertebrate dentitions with separate teeth in single or multiple tooth rows has been found to apply to dipnoan dentitions with fused teeth in a composite tooth plate. In this model, the epithelial invagination surrounding the margins of the tooth plate represents the dental lamina and, where this is in contact with mesenchymal cells, cell clusters (protogerms) arise. From these protogerms new odontodes (teeth) may develop if factors to inhibit differentiation are not present. Sites for initiation of odontodes become restricted to the labial margins of existing ridges on the tooth plate. Experimental studies on mammalian tooth germs are discussed and a model proposed for control of odontogenesis and histogenesis in dipnoan dentitions. Patterns of growth of hypermineralised petrodentine have been analysed and shown to depend initially on the arrangement of odontodes, and subsequently upon the ability of special cells in the pulp to generate new and wider layers of petrodentine. The initial pattern of petrodentine depends upon the position of odontodes in the forming ridges of the tooth plate. Subsequent patterns of petrodentine depend upon the extent of replacement growth beneath the tritural surface. Specialised cells, petroblasts, secrete the petrodentine within a shell of dentine. These cells differentiate from cells of the dental papilla after odontoblasts have begun to form dentine. They are regarded as a unique type of

  13. Germ cell specific overactivation of WNT/βcatenin signalling has no effect on folliculogenesis but causes fertility defects due to abnormal foetal development

    PubMed Central

    Kumar, Manish; Camlin, Nicole J.; Holt, Janet E.; Teixeira, Jose M.; McLaughlin, Eileen A.; Tanwar, Pradeep S.

    2016-01-01

    All the major components of the WNT signalling pathway are expressed in female germ cells and embryos. However, their functional relevance in oocyte biology is currently unclear. We examined ovaries collected from TCFGFP mice, a well-known Wnt reporter mouse model, and found dynamic changes in the Wnt/βcatenin signalling activity during different stages of oocyte development and maturation. To understand the functional importance of Wnt signalling in oocytes, we developed a mouse model with the germ cell-specific constitutive activation of βcatenin using cre recombinase driven by the DEAD (Asp-Glu-Ala-Asp) box protein 4 (Ddx4) gene promoter. Histopathological and functional analysis of ovaries from these mutant mice (Ctnnb1ex3cko) showed no defects in ovarian functions, oocytes, ovulation and early embryonic development. However, breeding of the Ctnnb1ex3cko female mice with males of known fertility never resulted in birth of mutant pups. Examination of uteri from time pregnant mutant females revealed defects in ectoderm differentiation leading to abnormal foetal development and premature death. Collectively, our work has established the role of active WNT/βcatenin signalling in oocyte biology and foetal development, and provides novel insights into the possible mechanisms of complications in human pregnancy such as repeated spontaneous abortion, sudden intrauterine unexpected foetal death syndrome and stillbirth. PMID:27265527

  14. Sexually dimorphic expression of Dmrt1 and γH2AX in germ stem cells during gonadal development in Xenopus laevis.

    PubMed

    Fujitani, Kazuko; Otomo, Asako; Wada, Mikako; Takamatsu, Nobuhiko; Ito, Michihiko

    2016-04-01

    In many animals, primordial germ cells (PGCs) migrate into developing gonads. There, they proliferate and differentiate into female and male germ stem cells (GSCs), oogonia and spermatogonia, respectively. Few studies have focused on the molecular mechanisms underlying the development of GSC sex determination. Here, we investigated the expression of the transcription factor Dmrt1 and a phosphorylated form of the histone variant H2AX (γH2AX) during gonadal development in Xenopus laevis. During early sexual differentiation, Dmrt1 was expressed in the GSCs of the ZW (female) and ZZ (male) gonads as well as somatic cells of the ZZ gonads. Notably, the PGCs and primary GSCs contained large, unstructured nuclei, whereas condensed, rounder nuclei appeared only in primary oogonia during tadpole development. After metamorphosis, Dmrt1 showed its expression in secondary spermatogonia, but not in secondary oogonia. Like Dmrt1, γH2AX was expressed in the nuclei of primary GSCs in early developing gonads. However, after metamorphosis, γH2AX expression continued in primary and secondary spermatogonia, but was barely detected in the condensed nuclei of primary oogonia. Taken together, these observations indicate that spermatogonia tend to retain PGC characteristics, compared to oogonia, which undergo substantial changes during gonadal differentiation in X. laevis. Our findings suggest that Dmrt1 and γH2AX may contribute to the maintenance of stem cell identity by controlling gene expression and epigenetic changes, respectively. PMID:27239441

  15. Germ cell specific overactivation of WNT/βcatenin signalling has no effect on folliculogenesis but causes fertility defects due to abnormal foetal development.

    PubMed

    Kumar, Manish; Camlin, Nicole J; Holt, Janet E; Teixeira, Jose M; McLaughlin, Eileen A; Tanwar, Pradeep S

    2016-01-01

    All the major components of the WNT signalling pathway are expressed in female germ cells and embryos. However, their functional relevance in oocyte biology is currently unclear. We examined ovaries collected from TCFGFP mice, a well-known Wnt reporter mouse model, and found dynamic changes in the Wnt/βcatenin signalling activity during different stages of oocyte development and maturation. To understand the functional importance of Wnt signalling in oocytes, we developed a mouse model with the germ cell-specific constitutive activation of βcatenin using cre recombinase driven by the DEAD (Asp-Glu-Ala-Asp) box protein 4 (Ddx4) gene promoter. Histopathological and functional analysis of ovaries from these mutant mice (Ctnnb1(ex3)cko) showed no defects in ovarian functions, oocytes, ovulation and early embryonic development. However, breeding of the Ctnnb1(ex3)cko female mice with males of known fertility never resulted in birth of mutant pups. Examination of uteri from time pregnant mutant females revealed defects in ectoderm differentiation leading to abnormal foetal development and premature death. Collectively, our work has established the role of active WNT/βcatenin signalling in oocyte biology and foetal development, and provides novel insights into the possible mechanisms of complications in human pregnancy such as repeated spontaneous abortion, sudden intrauterine unexpected foetal death syndrome and stillbirth. PMID:27265527

  16. Approaches for identifying germ cell mutagens: Report of the 2013 IWGT workshop on germ cell assays(☆).

    PubMed

    Yauk, Carole L; Aardema, Marilyn J; Benthem, Jan van; Bishop, Jack B; Dearfield, Kerry L; DeMarini, David M; Dubrova, Yuri E; Honma, Masamitsu; Lupski, James R; Marchetti, Francesco; Meistrich, Marvin L; Pacchierotti, Francesca; Stewart, Jane; Waters, Michael D; Douglas, George R

    2015-05-01

    This workshop reviewed the current science to inform and recommend the best evidence-based approaches on the use of germ cell genotoxicity tests. The workshop questions and key outcomes were as follows. (1) Do genotoxicity and mutagenicity assays in somatic cells predict germ cell effects? Limited data suggest that somatic cell tests detect most germ cell mutagens, but there are strong concerns that dictate caution in drawing conclusions. (2) Should germ cell tests be done, and when? If there is evidence that a chemical or its metabolite(s) will not reach target germ cells or gonadal tissue, it is not necessary to conduct germ cell tests, notwithstanding somatic outcomes. However, it was recommended that negative somatic cell mutagens with clear evidence for gonadal exposure and evidence of toxicity in germ cells could be considered for germ cell mutagenicity testing. For somatic mutagens that are known to reach the gonadal compartments and expose germ cells, the chemical could be assumed to be a germ cell mutagen without further testing. Nevertheless, germ cell mutagenicity testing would be needed for quantitative risk assessment. (3) What new assays should be implemented and how? There is an immediate need for research on the application of whole genome sequencing in heritable mutation analysis in humans and animals, and integration of germ cell assays with somatic cell genotoxicity tests. Focus should be on environmental exposures that can cause de novo mutations, particularly newly recognized types of genomic changes. Mutational events, which may occur by exposure of germ cells during embryonic development, should also be investigated. Finally, where there are indications of germ cell toxicity in repeat dose or reproductive toxicology tests, consideration should be given to leveraging those studies to inform of possible germ cell genotoxicity. PMID:25953399

  17. Evaluation of the non-functional tooth contact in patients with temporomandibular disorders by using newly developed electronic system

    PubMed Central

    Funato, M; Ono, Y; Baba, K; Kudo, Y

    2014-01-01

    The aims of this study were to introduce a novel electronic system for reliable evaluation of the non-functional tooth contact in patients with temporomandibular disorders (TMDs) and investigate the possible associations between the non-functional tooth contact and some characteristics of the patients with TMD. We designed and installed a software program to send emails regarding the non-functional tooth contact to the subjects' preregistered cellular phones at intervals of 20 ± 9 min daily for 10 consecutive days. Twelve patients with TMD and 12 gender- and age-matched healthy subjects responded via emails to one of 3 choices: no tooth contact, tooth contact during oral functions or tooth contact not associated with oral functions. The influence of subjective stress, anxiety, depression, personality and daily activities on tooth contact was then assessed. The frequency of the non-functional tooth contact was significantly higher in the patients with TMD than in the healthy subjects (35·0% vs. 9·6%, P < 0·001), while no significant group difference was found for the frequency of functional tooth contact, the stress, anxiety, depression and personality. PMID:24447128

  18. The biology of the germ line in echinoderms.

    PubMed

    Wessel, Gary M; Brayboy, Lynae; Fresques, Tara; Gustafson, Eric A; Oulhen, Nathalie; Ramos, Isabela; Reich, Adrian; Swartz, S Zachary; Yajima, Mamiko; Zazueta, Vanessa

    2014-08-01

    The formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ-line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ-line determination in echinoderms, an early-branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ-line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ-line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser-known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ-line fate determination. This enables a strongly contrasted picture for germ-line determination in this phylum, but one for which transitions between different modes of germ-line determination might now be experimentally addressed. PMID:23900765

  19. The Biology of the Germ line in Echinoderms

    PubMed Central

    Wessel, Gary M.; Brayboy, Lynae; Fresques, Tara; Gustafson, Eric A.; Oulhen, Nathalie; Ramos, Isabela; Reich, Adrian; Swartz, S. Zachary; Yajima, Mamiko; Zazueta, Vanessa

    2014-01-01

    SUMMARY The formation of the germ line in an embryo marks a fresh round of reproductive potential. The developmental stage and location within the embryo where the primordial germ cells (PGCs) form, however, differs markedly among species. In many animals, the germ line is formed by an inherited mechanism, in which molecules made and selectively partitioned within the oocyte drive the early development of cells that acquire this material to a germ-line fate. In contrast, the germ line of other animals is fated by an inductive mechanism that involves signaling between cells that directs this specialized fate. In this review, we explore the mechanisms of germ-line determination in echinoderms, an early-branching sister group to the chordates. One member of the phylum, sea urchins, appears to use an inherited mechanism of germ-line formation, whereas their relatives, the sea stars, appear to use an inductive mechanism. We first integrate the experimental results currently available for germ line determination in the sea urchin, for which considerable new information is available, and then broaden the investigation to the lesser-known mechanisms in sea stars and other echinoderms. Even with this limited insight, it appears that sea stars, and perhaps the majority of the echinoderm taxon, rely on inductive mechanisms for germ-line fate determination. This enables a strongly contrasted picture for germ-line determination in this phylum, but one for which transitions between different modes of germ-line determination might now be experimentally addressed. PMID:23900765

  20. Dental Caries (Tooth Decay)

    MedlinePlus

    ... Find Data by Topic > Dental Caries (Tooth Decay) Dental Caries (Tooth Decay) Main Content Dental caries (tooth decay) remains the most prevalent chronic ... important source of information on oral health and dental care in the United States since the early ...

  1. Seal Out Tooth Decay

    MedlinePlus

    ... Topics > Tooth Decay (Caries) > Seal Out Tooth Decay Seal Out Tooth Decay Main Content What are dental ... back teeth decay so easily? Who should get seal​ants? Should sealants be put on baby teeth? ...

  2. RNA binding protein Musashi-1 directly targets Msi2 and Erh during early testis germ cell development and interacts with IPO5 upon translocation to the nucleus.

    PubMed

    Sutherland, Jessie M; Sobinoff, Alexander P; Fraser, Barbara A; Redgrove, Kate A; Davidson, Tara-Lynne; Siddall, Nicole A; Koopman, Peter; Hime, Gary R; McLaughlin, Eileen A

    2015-07-01

    Controlled gene regulation during gamete development is vital for maintaining reproductive potential. During the process of gamete development, male germ cells experience extended periods of inactive transcription despite requirements for continued growth and differentiation. Spermatogenesis therefore provides an ideal model to study the effects of posttranscriptional control on gene regulation. During spermatogenesis posttranscriptional regulation is orchestrated by abundantly expressed RNA-binding proteins. One such group of RNA-binding proteins is the Musashi family, previously identified as a critical regulator of testis germ cell development and meiosis in Drosophila and also shown to be vital to sperm development and reproductive potential in the mouse. We focus in depth on the role and function of the vertebrate Musashi ortholog Musashi-1 (MSI1). Through detailed expression studies and utilizing our novel transgenic Msi1 testis-specific overexpression model, we have identified 2 unique RNA-binding targets of MSI1 in spermatogonia, Msi2 and Erh, and have demonstrated a role for MSI1 in translational regulation. We have also provided evidence to suggest that nuclear import protein, IPO5, facilitates the nuclear translocation of MSI1 to the transcriptionally silenced XY chromatin domain in meiotic pachytene spermatocytes, resulting in the release of MSI1 RNA-binding targets. This firmly establishes MSI1 as a master regulator of posttranscriptional control during early spermatogenesis and highlights the significance of the subcellular localization of RNA binding proteins in relation to their function. PMID:25782991

  3. [Tooth regeneration--dream to reality].

    PubMed

    Wang, Song-Ling; Wang, Xue-Jiu

    2008-04-01

    Tooth or dentition missing compromises human health physically and psychiatrically. Although several prosthesis methods are used to restore tooth loss, these restorations are still non-biological methods. It is a dream for human being to regenerate a real tooth for hundreds years. There are two ways to regenerate the tooth. One is application of conventional tissue engineering techniques including seed cells and scaffold. The other is regeneration tooth using dental epithelium and dental mesenchymal cells based on the knowledge of tooth initiation and development. Marked progress has been achieved in these two ways, while there is still a long way to go. Recently a new concept has been proposed for regeneration of a biological tooth root based on tooth-related stem cells and tissue engineering technique. A biological tooth root has been regenerated in swine. It may be a valuable method for restoration of tooth loss before successful whole tooth regeneration. A latest research showed that a subpopulation in bone marrow cells can give rise to ameloblast-like cells when mixed with embryonic epithelium and reassociation with integrated mesenchyme, which may provide a new seed cell source for tooth regeneration. PMID:18605442

  4. What Are Germs?

    MedlinePlus

    ... four major types of germs are: bacteria, viruses, fungi, and protozoa. They can invade plants, animals, and ... countertop, be sure to wash your hands regularly! Fungi (say: FUN-guy) are multi-celled (made of ...

  5. Microfluidics co-culture systems for studying tooth innervation

    PubMed Central

    Pagella, Pierfrancesco; Neto, Estrela; Jiménez-Rojo, Lucia; Lamghari, Meriem; Mitsiadis, Thimios A.

    2014-01-01

    Innervation plays a key role in the development and homeostasis of organs and tissues of the orofacial complex. Among these structures, teeth are peculiar organs as they are not innervated until later stages of development. Furthermore, the implication of neurons in tooth initiation, morphogenesis and differentiation is still controversial. Co-cultures constitute a valuable method to investigate and manipulate the interactions of nerve fibers with their target organs in a controlled and isolated environment. Conventional co-cultures between neurons and their target tissues have already been performed, but these cultures do not offer optimal conditions that are closely mimicking the in vivo situation. Indeed, specific cell populations require different culture media in order to preserve their physiological properties. In this study we evaluate the usefulness of a microfluidics system for co-culturing mouse trigeminal ganglia and developing teeth. This device allows the application of specific media for the appropriate development of both neuronal and dental tissues. The results show that mouse trigeminal ganglia and teeth survive for long culture periods in this microfluidics system, and that teeth maintain the attractive or repulsive effect on trigeminal neurites that has been observed in vivo. Neurites are repealed when co-cultured with embryonic tooth germs, while postnatal teeth exert an attractive effect to trigeminal ganglia-derived neurons. In conclusion, microfluidics system devices provide a valuable tool for studying the behavior of neurons during the development of orofacial tissues and organs, faithfully imitating the in vivo situation. PMID:25202282

  6. Specifying and protecting germ cell fate

    PubMed Central

    Strome, Susan; Updike, Dustin

    2015-01-01

    Germ cells are the special cells in the body that undergo meiosis to generate gametes and subsequently entire new organisms after fertilization, a process that continues generation after generation. Recent studies have expanded our understanding of the factors and mechanisms that specify germ cell fate, including the partitioning of maternally supplied ‘germ plasm’, inheritance of epigenetic memory and expression of transcription factors crucial for primordial germ cell (PGC) development. Even after PGCs are specified, germline fate is labile and thus requires protective mechanisms, such as global transcriptional repression, chromatin state alteration and translation of only germline-appropriate transcripts. Findings from diverse species continue to provide insights into the shared and divergent needs of these special reproductive cells. PMID:26122616

  7. Sex determination in mammalian germ cells

    PubMed Central

    Spiller, Cassy M; Bowles, Josephine

    2015-01-01

    Germ cells are the precursors of the sperm and oocytes and hence are critical for survival of the species. In mammals, they are specified during fetal life, migrate to the developing gonads and then undergo a critical period during which they are instructed, by the soma, to adopt the appropriate sexual fate. In a fetal ovary, germ cells enter meiosis and commit to oogenesis, whereas in a fetal testis, they avoid entry into meiosis and instead undergo mitotic arrest and mature toward spermatogenesis. Here, we discuss what we know so far about the regulation of sex-specific differentiation of germ cells, considering extrinsic molecular cues produced by somatic cells, as well as critical intrinsic changes within the germ cells. This review focuses almost exclusively on our understanding of these events in the mouse model. PMID:25791730

  8. Ultrastructural Studies of Germ Cell Development and the Functions of Leydig Cells and Sertoli Cells associated with Spermatogenesis in Kareius bicoloratus (Teleostei, Pleuronectiformes, Pleuronectidae)

    PubMed Central

    Kang, Hee-Woong; Kim, Sung Hwan; Chung, Jae Seung

    2016-01-01

    The ultrastructures of germ cells and the functions of Leydig cells and Sertoli cells during spermatogenesis inmale Kareius bicoloratus (Pleuronectidae) were investigated by electron microscope observation. Each of the well-developed Leydig cells during active maturation division and before spermiation contained an ovoid vesicular nucleus, a number of smooth endoplasmic reticula, well-developed tubular or vesicular mitochondrial cristae, and several lipid droplets in the cytoplasm. It is assumed that Leydig cells are typical steroidogenic cells showing cytological characteristics associated with male steroidogenesis. No cyclic structural changes in the Leydig cells were observed through the year. However, although no clear evidence of steroidogenesis or of any transfer of nutrients from the Sertoli cells to spermatogenic cells was observed, cyclic structural changes in the Sertoli cells were observed over the year. During the period of undischarged germ cell degeneration after spermiation, the Sertoli cells evidenced a lysosomal system associated with phagocytic function in the seminiferous lobules. In this study, the Sertoli cells function in phagocytosis and the resorption of products originating from degenerating spermatids and spermatozoa after spermiation. The spermatozoon lacks an acrosome, as have been shown in all teleost fish spermatozoa. The flagellum or sperm tail of this species evidences the typical 9+2 array of microtubules. PMID:27294207

  9. A Reappraisal of Developing Permanent Tooth Length as an Estimate of Age in Human Immature Skeletal Remains.

    PubMed

    Cardoso, Hugo F V; Spake, Laure; Liversidge, Helen M

    2016-09-01

    This study expands on existing juvenile age prediction models from tooth length by increasing sample size and using classical calibration. A sample of 178 individuals from two European known sex and age skeletal samples was used to calculate prediction formulae for each tooth for each sex separately and combined. Prediction errors, residuals, and percentage of individuals whose real age fell within the 95% prediction interval were calculated. An ANCOVA was used to test sex and sample differences. Tooth length for age does not differ between the samples except for the canine and second premolar, and no statistically significant sex differences were detected. The least prediction error was found in the incisors and the first molar, and the highest prediction error was found in the third molar. Age prediction formulae provided here can be easily used in a variety of contexts where tooth length is measured from any isolated tooth. PMID:27320642

  10. Conservation and variation in enamel protein distribution during vertebrate tooth development.

    PubMed

    Satchell, Paul G; Anderton, Xochitl; Ryu, Okhee H; Luan, Xianghong; Ortega, Adam J; Opamen, Rene; Berman, Brett J; Witherspoon, David E; Gutmann, James L; Yamane, Akira; Zeichner-David, Margerita; Simmer, James P; Shuler, Charles F; Diekwisch, Thomas G H

    2002-08-15

    Vertebrate enamel formation is a unique synthesis of the function of highly specialized enamel proteins and their effect on the growth and organization of apatite crystals. Among tetrapods, the physical structure of enamel is highly conserved, while there is a greater variety of enameloid tooth coverings in fish. In the present study, we postulated that in enamel microstructures of similar organization, the principle components of the enamel protein matrix would have to be highly conserved. In order to identify the enamel proteins that might be most highly conserved and thus potentially most essential to the process of mammalian enamel formation, we used immunoscreening with enamel protein antibodies as a means to assay for degrees of homology to mammalian enamel proteins. Enamel preparations from mouse, gecko, frog, lungfish, and shark were screened with mammalian enamel protein antibodies, including amelogenin, enamelin, tuftelin, MMP20, and EMSP1. Our results demonstrated that amelogenin was the most highly conserved enamel protein associated with the enamel organ, enamelin featured a distinct presence in shark enameloid but was also present in the enamel organ of other species, while the other enamel proteins, tuftelin, MMP20, and EMSP1, were detected in both in the enamel organ and in other tissues of all species investigated. We thus conclude that the investigated enamel proteins, amelogenin, enamelin, tuftelin, MMP20, and EMSP1, were highly conserved in a variety of vertebrate species. We speculate that there might be a unique correlation between amelogenin-rich tetrapod and lungfish enamel with long and parallel crystals and enamelin-rich basal vertebrate enameloid with diverse patterns of crystal organization. PMID:12210110

  11. Aubergine iCLIP Reveals piRNA-Dependent Decay of mRNAs Involved in Germ Cell Development in the Early Embryo

    PubMed Central

    Barckmann, Bridlin; Pierson, Stéphanie; Dufourt, Jérémy; Papin, Catherine; Armenise, Claudia; Port, Fillip; Grentzinger, Thomas; Chambeyron, Séverine; Baronian, Grégory; Desvignes, Jean-Pierre; Curk, Tomaz; Simonelig, Martine

    2015-01-01

    Summary The Piwi-interacting RNA (piRNA) pathway plays an essential role in the repression of transposons in the germline. Other functions of piRNAs such as post-transcriptional regulation of mRNAs are now emerging. Here, we perform iCLIP with the PIWI protein Aubergine (Aub) and identify hundreds of maternal mRNAs interacting with Aub in the early Drosophila embryo. Gene expression profiling reveals that a proportion of these mRNAs undergo Aub-dependent destabilization during the maternal-to-zygotic transition. Strikingly, Aub-dependent unstable mRNAs encode germ cell determinants. iCLIP with an Aub mutant that is unable to bind piRNAs confirms piRNA-dependent binding of Aub to mRNAs. Base pairing between piRNAs and mRNAs can induce mRNA cleavage and decay that are essential for embryonic development. These results suggest general regulation of maternal mRNAs by Aub and piRNAs, which plays a key developmental role in the embryo through decay and localization of mRNAs encoding germ cell determinants. PMID:26257181

  12. Utility of OCT3/4, TSPY and β-Catenin as Biological Markers for Gonadoblastoma Formation and Malignant Germ Cell Tumor Development in Dysgenetic Gonads

    PubMed Central

    Palma, Icela; Garibay, Nayely; Pena-Yolanda, Rocio; Contreras, Alejandra; Raya, Atlantida; Dominguez, Carolina; Romero, Mirna; Aristi, Gerardo; Queipo, Gloria

    2013-01-01

    BACKGROUND: Gonadoblastoma (GB) is regarded as an in situ form of germ cell tumor in dysgenetic gonads, and 30% of patients with GB develop a dysgerminoma/seminoma tumor. OBJECTIVE: Determine whether OCT3/4 and β-catenin are expressed in dysgenetic gonads before GB development and whether TSPY participates in the OCT3/4-β-catenin pathways in the malignant invasive behavior. METHODS: dysgenetic gonads of Disorders of sex differentiation (DSD) patients with mixed gonadal dysgenesis were analyzed by immunohistochemistry and immunofluorescence for comparison with GB and dysgerminoma/seminoma. RESULTS: Our results suggest that the development of GB is secondary to the interaction of OCT3/4 and TSPY, that β-catenin does not participate in this process. CONCLUSIONS: The use of this biological markers detects the potential high risk gonads. PMID:23396295

  13. Dissecting Germ Cell Metabolism through Network Modeling

    PubMed Central

    Whitmore, Leanne S.; Ye, Ping

    2015-01-01

    Metabolic pathways are increasingly postulated to be vital in programming cell fate, including stemness, differentiation, proliferation, and apoptosis. The commitment to meiosis is a critical fate decision for mammalian germ cells, and requires a metabolic derivative of vitamin A, retinoic acid (RA). Recent evidence showed that a pulse of RA is generated in the testis of male mice thereby triggering meiotic commitment. However, enzymes and reactions that regulate this RA pulse have yet to be identified. We developed a mouse germ cell-specific metabolic network with a curated vitamin A pathway. Using this network, we implemented flux balance analysis throughout the initial wave of spermatogenesis to elucidate important reactions and enzymes for the generation and degradation of RA. Our results indicate that primary RA sources in the germ cell include RA import from the extracellular region, release of RA from binding proteins, and metabolism of retinal to RA. Further, in silico knockouts of genes and reactions in the vitamin A pathway predict that deletion of Lipe, hormone-sensitive lipase, disrupts the RA pulse thereby causing spermatogenic defects. Examination of other metabolic pathways reveals that the citric acid cycle is the most active pathway. In addition, we discover that fatty acid synthesis/oxidation are the primary energy sources in the germ cell. In summary, this study predicts enzymes, reactions, and pathways important for germ cell commitment to meiosis. These findings enhance our understanding of the metabolic control of germ cell differentiation and will help guide future experiments to improve reproductive health. PMID:26367011

  14. Dissecting Germ Cell Metabolism through Network Modeling.

    PubMed

    Whitmore, Leanne S; Ye, Ping

    2015-01-01

    Metabolic pathways are increasingly postulated to be vital in programming cell fate, including stemness, differentiation, proliferation, and apoptosis. The commitment to meiosis is a critical fate decision for mammalian germ cells, and requires a metabolic derivative of vitamin A, retinoic acid (RA). Recent evidence showed that a pulse of RA is generated in the testis of male mice thereby triggering meiotic commitment. However, enzymes and reactions that regulate this RA pulse have yet to be identified. We developed a mouse germ cell-specific metabolic network with a curated vitamin A pathway. Using this network, we implemented flux balance analysis throughout the initial wave of spermatogenesis to elucidate important reactions and enzymes for the generation and degradation of RA. Our results indicate that primary RA sources in the germ cell include RA import from the extracellular region, release of RA from binding proteins, and metabolism of retinal to RA. Further, in silico knockouts of genes and reactions in the vitamin A pathway predict that deletion of Lipe, hormone-sensitive lipase, disrupts the RA pulse thereby causing spermatogenic defects. Examination of other metabolic pathways reveals that the citric acid cycle is the most active pathway. In addition, we discover that fatty acid synthesis/oxidation are the primary energy sources in the germ cell. In summary, this study predicts enzymes, reactions, and pathways important for germ cell commitment to meiosis. These findings enhance our understanding of the metabolic control of germ cell differentiation and will help guide future experiments to improve reproductive health. PMID:26367011

  15. Sex Specification and Heterogeneity of Primordial Germ Cells in Mice

    PubMed Central

    Sakashita, Akihiko; Kawabata, Yukiko; Jincho, Yuko; Tajima, Shiun; Kumamoto, Soichiro; Kobayashi, Hisato; Matsui, Yasuhisa; Kono, Tomohiro

    2015-01-01

    In mice, primordial germ cells migrate into the genital ridges by embryonic day 13.5 (E13.5), where they are then subjected to a sex-specific fate with female and male primordial germ cells undergoing mitotic arrest and meiosis, respectively. However, the sex-specific basis of primordial germ cell differentiation is poorly understood. The aim of this study was to investigate the sex-specific features of mouse primordial germ cells. We performed RNA-sequencing (seq) of E13.5 female and male mouse primordial germ cells using next-generation sequencing. We identified 651 and 428 differentially expressed transcripts (>2-fold, P < 0.05) in female and male primordial germ cells, respectively. Of these, many transcription factors were identified. Gene ontology and network analysis revealed differing functions of the identified female- and male-specific genes that were associated with primordial germ cell acquisition of sex-specific properties required for differentiation into germ cells. Furthermore, DNA methylation and ChIP-seq analysis of histone modifications showed that hypomethylated gene promoter regions were bound with H3K4me3 and H3K27me3. Our global transcriptome data showed that in mice, primordial germ cells are decisively assigned to a sex-specific differentiation program by E13.5, which is necessary for the development of vital germ cells. PMID:26700643

  16. Expression analysis of candidate genes regulating successional tooth formation in the human embryo

    PubMed Central

    Olley, Ryan; Xavier, Guilherme M.; Seppala, Maisa; Volponi, Ana A.; Geoghegan, Fin; Sharpe, Paul T.; Cobourne, Martyn T.

    2014-01-01

    Human dental development is characterized by formation of primary teeth, which are subsequently replaced by the secondary dentition. The secondary dentition consists of incisors, canines, and premolars, which are derived from the successional dental lamina of the corresponding primary tooth germs; and molar teeth, which develop as a continuation of the dental lamina. Currently, very little is known about the molecular regulation of human successional tooth formation. Here, we have investigated expression of three candidate regulators for human successional tooth formation; the Fibroblast Growth Factor-antagonist SPROUTY2, the Hedgehog co-receptor GAS1 and the RUNT-related transcription factor RUNX2. At around 8 weeks of development, only SPROUTY2 showed strong expression in both epithelium and mesenchyme of the early bud. During the cap stage between 12–14 weeks, SPROUTY2 predominated in the dental papilla and inner enamel epithelium of the developing tooth. No specific expression was seen in the successional dental lamina. GAS1 was expressed in dental papilla and follicle, and associated with mesenchyme adjacent to the primary dental lamina during the late cap stage. In addition, GAS1 was identifiable in mesenchyme adjacent to the successional lamina, particularly in the developing primary first molar. For RUNX2, expression predominated in the dental papilla and follicle. Localized expression was seen in mesenchyme adjacent to the primary dental lamina at the late cap stage; but surprisingly, not in the early successional lamina at these stages. These findings confirm that SPROUTY2, GAS1, and RUNX2 are all expressed during early human tooth development. The domains of GAS1 and RUNX2 are consistent with a role influencing function of the primary dental lamina but only GAS1 transcripts were identifiable in the successional lamina at these early stages of development. PMID:25484868

  17. Evolution of High Tooth Replacement Rates in Sauropod Dinosaurs

    PubMed Central

    Smith, Kathlyn M.; Fisher, Daniel C.; Wilson, Jeffrey A.

    2013-01-01

    Background Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates. Methodology/Principal Findings We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days). Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section. Conclusions/Significance Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size), and derived titanosaurs and diplodocoids independently

  18. Dental implant as an option for tooth replacement: The awareness of patients at a tertiary hospital in a developing country

    PubMed Central

    Gbadebo, Olaide Shakeerah; Lawal, Folake Barakat; Sulaiman, Amidu Omotayo; Ajayi, Deborah Mojirade

    2014-01-01

    Aim: A survey was set out to evaluate the knowledge of patients about tooth replacement as a whole, and assess their awareness of implant-retained prosthesis as an option of tooth replacement. Materials and Methods: Information on sociodemographic characteristics, knowledge about implant-retained tooth as an option for missing tooth replacement, cost implication, source of information and knowledge about other options of tooth replacement were obtained from patients attending the dental clinics of the University College Hospital, Ibadan, using structured self-administered questionnaires. Data were analyzed using SPSS version 20. Result: A total of 220 patients aged 18-84 years with a mean age of 37.6 (±16.5) years participated in the study, with a male to female ratio of 1:1.1. The majority (92.5%) knew that missing teeth can be replaced, while a significantly lower proportion (28.9%) knew about dental implants as an option (P < 0.01). Dentists were the major source of information on dental implants (68%). Only 21 (36.8%) of those who had heard about dental implant had knowledge about the cost (P < 0.000). Conclusion: A low level of awareness about dental implant as tooth replacement option exist in this environment, although most of the study participants were aware that missing teeth can be replaced. PMID:25191063

  19. Extragonadal Germ Cell Cancer (EGC)

    MedlinePlus

    ... Testicular Cancer Resource Center Extragonadal Germ Cell Cancer (EGC) 95% of all testicular tumors are germ cell ... seen in young adults. Patients with mediastinal nonseminomatous EGC are typically classed as poor risk patients because ...

  20. Molecular Genetics of Supernumerary Tooth Formation

    PubMed Central

    Wang, Xiu-Ping; Fan, Jiabing

    2011-01-01

    Summary Despite advances in the knowledge of tooth morphogenesis and differentiation, relatively little is known about the aetiology and molecular mechanisms underlying supernumerary tooth formation. A small number of supernumerary teeth may be a common developmental dental anomaly, while multiple supernumerary teeth usually have a genetic component and they are sometimes thought to represent a partial third dentition in humans. Mice, which are commonly used for studying tooth development, only exhibit one dentition, with very few mouse models exhibiting supernumerary teeth similar to those in humans. Inactivation of Apc or forced activation of Wnt/β(catenin signalling results in multiple supernumerary tooth formation in both humans and in mice, but the key genes in these pathways are not very clear. Analysis of other model systems with continuous tooth replacement or secondary tooth formation, such as fish, snake, lizard, and ferret, is providing insights into the molecular and cellular mechanisms underlying succesional tooth development, and will assist in the studies on supernumerary tooth formation in humans. This information, together with the advances in stem cell biology and tissue engineering, will pave ways for the tooth regeneration and tooth bioengineering. PMID:21309064

  1. [Medicolegal considerations. Apropos of tooth germ transplantation between 2 twins].

    PubMed

    Cros, P; Vaillant, J M; Delaire, J; Freidel, M; Clerc, J P

    1991-01-01

    With regard to medicolegal problems, semantics are of considerable importance: indeed, depending on whether we call grafting or transplantation of an organ the operation that takes a living organ to reimplant it in the same person or the operation that takes a living organ from a donor to reimplant it in a recipient, the issues raised are completely different. The transposition of a dental organ does not raise any particular problems apart from the technical requirements to be met; there is no special problem of prevention or ethics to be taken into consideration. The problem is a completely different one when it means taking a living organ from a living or dead subject and reimplanting it in another subject. All measures decreed from the point of view of law and regulations that are dictated by considerations of prevention and ethics must then be strictly applied. PMID:1784985

  2. Histological observation of germ cell development and discovery of spermatophores in ovoviviparous black rockfish ( Sebastes schlegeli Hilgendorf) in reproductive season

    NASA Astrophysics Data System (ADS)

    Feng, Junrong; Liu, Liming; Jiang, Haibin; Wang, Maojian; Du, Rongbin

    2014-10-01

    Black rockfish ( Sebastes schlegeli) is an important species for culture; however, its reproductive characteristics have not been fully documented. In this study, we investigated the morphology and developmental process of germ cells in this ovoviviparous rockfish in reproductive season (October 2011-November 2012) with histological methods. We found that the gonad of mature fish showed notable seasonal changes in developmental characteristics and morphological structure. The sperm cells matured during a period lasting from October to December, significantly earlier than the oocytes did. A large number of spermatozoa and other cells occurred in testis at different developmental stages. Vitellogenesis in oocytes began in October, and gestation appeared in April next year. Spermatophores were discovered for the first time in Sebastes, which assembled in testis, main sperm duct, oviduct and genital tract, as well as ovarian cavity in October and April. These organs may serve either as production or hiding places for spermatophores and spermatozoa which were stored and transported in form of spermatophores. Testicular degeneration started from the distal part of testis in April, with spermatophores assembled in degenerating testis and waiting for transportation. The copulation probably lasted for a long period, during which the spermatozoa were discharged in batches as spermatophores. These spermatophores were coated with sticky materials secreted from the interstitial areas of testis and the main sperm duct, then transported into ovary.

  3. Chick tooth induction revisited.

    PubMed

    Cai, Jinglei; Cho, Sung-Won; Ishiyama, Mikio; Mikami, Masato; Hosoya, Akihiro; Kozawa, Yukishige; Ohshima, Hayato; Jung, Han-Sung

    2009-07-15

    Teeth have been missing from Aves for almost 100 million years. However, it is believed that the avian oral epithelium retains the molecular signaling required to induce odontogenesis, and this has been widely examined using heterospecific recombinations with mouse dental mesenchyme. It has also been argued that teeth can form from the avian oral epithelium owing to contamination of the mouse mesenchyme with mouse dental epithelial cells. To investigate the possibility of tooth formation from chick oral epithelium and the characteristics of possible chick enamel, we applied LacZ transgenic mice during heterospecific recombination and examined the further tooth formation. Transmission electron microscopy was used to identify the two tissues during development after heterospecific recombination. No mixing was detected between chick oral epithelium and mouse dental mesenchyme after 2 days, and secretory ameloblasts with Tomes' processes were observed after 1 week. Teeth were formed after 3 weeks with a single cusp pattern, possibly determined by epithelial factors, which is similar to that of the avian tooth in the late Jurassic period. These recombinant teeth were smaller than mouse molars, whereas perfect structures of both ameloblasts and enamel showed histological characteristics similar to those of mice. Together these observations consistent with previous report that odontogenesis is initially directed by species-specific mesenchymal signals interplaying with common epithelial signals. PMID:19226602

  4. AiGERM: A logic programming front end for GERM

    NASA Technical Reports Server (NTRS)

    Hashim, Safaa H.

    1990-01-01

    AiGerm (Artificially Intelligent Graphical Entity Relation Modeler) is a relational data base query and programming language front end for MCC (Mission Control Center)/STP's (Space Test Program) Germ (Graphical Entity Relational Modeling) system. It is intended as an add-on component of the Germ system to be used for navigating very large networks of information. It can also function as an expert system shell for prototyping knowledge-based systems. AiGerm provides an interface between the programming language and Germ.

  5. Testicular germ cell tumours.

    PubMed

    Rajpert-De Meyts, Ewa; McGlynn, Katherine A; Okamoto, Keisei; Jewett, Michael A S; Bokemeyer, Carsten

    2016-04-23

    Testicular germ cell tumours are at the crossroads of developmental and neoplastic processes. Their cause has not been fully elucidated but differences in incidences suggest that a combination of genetic and environment factors are involved, with environmental factors predominating early in life. Substantial progress has been made in understanding genetic susceptibility in the past 5 years on the basis of the results of large genome-wide association studies. Testicular germ cell tumours are highly sensitive to radiotherapy and chemotherapy and hence have among the best outcomes of all tumours. Because the tumours occur mainly in young men, preservation of reproductive function, quality of life after treatment, and late effects are crucial concerns. In this Seminar, we provide an overview of advances in the understanding of the epidemiology, genetics, and biology of testicular germ cell tumours. We also summarise the consensus on how to treat testicular germ cell tumours and focus on a few controversies and improvements in the understanding of late effects of treatment and quality of life for survivors. PMID:26651223

  6. αE-catenin inhibits YAP/TAZ activity to regulate signalling centre formation during tooth development.

    PubMed

    Li, Chun-Ying; Hu, Jimmy; Lu, Hongbing; Lan, Jing; Du, Wei; Galicia, Nicole; Klein, Ophir D

    2016-01-01

    Embryonic signalling centres are specialized clusters of non-proliferating cells that direct the development of many organs. However, the mechanisms that establish these essential structures in mammals are not well understood. Here we report, using the murine incisor as a model, that αE-catenin is essential for inhibiting nuclear YAP localization and cell proliferation. This function of αE-catenin is required for formation of the tooth signalling centre, the enamel knot (EK), which maintains dental mesenchymal condensation and epithelial invagination. EK formation depends primarily on the signalling function of αE-catenin through YAP and its homologue TAZ, as opposed to its adhesive function, and combined deletion of Yap and Taz rescues the EK defects caused by loss of αE-catenin. These findings point to a developmental mechanism by which αE-catenin restricts YAP/TAZ activity to establish a group of non-dividing and specialized cells that constitute a signalling centre. PMID:27405641

  7. αE-catenin inhibits YAP/TAZ activity to regulate signalling centre formation during tooth development

    PubMed Central

    Li, Chun-Ying; Hu, Jimmy; Lu, Hongbing; Lan, Jing; Du, Wei; Galicia, Nicole; Klein, Ophir D.

    2016-01-01

    Embryonic signalling centres are specialized clusters of non-proliferating cells that direct the development of many organs. However, the mechanisms that establish these essential structures in mammals are not well understood. Here we report, using the murine incisor as a model, that αE-catenin is essential for inhibiting nuclear YAP localization and cell proliferation. This function of αE-catenin is required for formation of the tooth signalling centre, the enamel knot (EK), which maintains dental mesenchymal condensation and epithelial invagination. EK formation depends primarily on the signalling function of αE-catenin through YAP and its homologue TAZ, as opposed to its adhesive function, and combined deletion of Yap and Taz rescues the EK defects caused by loss of αE-catenin. These findings point to a developmental mechanism by which αE-catenin restricts YAP/TAZ activity to establish a group of non-dividing and specialized cells that constitute a signalling centre. PMID:27405641

  8. Functional implication of nucleolin in the mouse first molar development.

    PubMed

    Xie, Ming; Kobayashi, Ieyoshi; Kiyoshima, Tamotsu; Yamaza, Haruyoshi; Honda, Jun-ya; Takahashi, Keiko; Enoki, Norio; Akamine, Akifumi; Sakai, Hidetaka

    2007-08-10

    We examined the functional implication of nucleolin in the mouse first molar development. Both the nucleolin mRNA and protein expressions were demonstrated in the odontogenic epithelial cells in the early stage and in the inner enamel epithelial layer in the late stage. The expression pattern of nucleolin corresponded to the proliferating cells in the tooth germ, thus showing that nucleolin could possibly be related to cell proliferation. No in situ signal of nucleolin was found in the primary enamel knot (PEK). Furthermore, nucleolin protein was demonstrated in the PEK by immunohistochemistry. The existence of nucleolin protein in the PEK may possibly be related to the apoptosis in the PEK cells. An inhibition assay using the hemagglutinating virus of Japan-liposome containing nucleolin antisense phosphorothioated oligonucleotide (AS S-ODN) in cultured mouse mandibles at embryonic day (E) 11.0 showed a marked growth inhibition of tooth germ. Moreover, no developmental arrest was found in the cultured tooth germ at E15.0 treated with nucleolin AS S-ODN. Real time PCR was performed to examine the mRNA expression of nucleolin-related genes, and a significant reduction in the midkine mRNA expression was thus observed in the mouse mandible after being treated with nucleolin AS S-ODN. This inhibition assay indicated that nucleolin could thus be involved in the early stage of tooth germ initiation and morphogenesis, possibly by regulating the midkine expression. PMID:17562718

  9. Development of germ-line-specific CRISPR-Cas9 systems to improve the production of heritable gene modifications in Arabidopsis.

    PubMed

    Mao, Yanfei; Zhang, Zhengjing; Feng, Zhengyan; Wei, Pengliang; Zhang, Hui; Botella, José Ramón; Zhu, Jian-Kang

    2016-02-01

    The Streptococcus-derived CRISPR/Cas9 system is being widely used to perform targeted gene modifications in plants. This customized endonuclease system has two components, the single-guide RNA (sgRNA) for target DNA recognition and the CRISPR-associated protein 9 (Cas9) for DNA cleavage. Ubiquitously expressed CRISPR/Cas9 systems (UC) generate targeted gene modifications with high efficiency but only those produced in reproductive cells are transmitted to the next generation. We report the design and characterization of a germ-line-specific Cas9 system (GSC) for Arabidopsis gene modification in male gametocytes, constructed using a SPOROCYTELESS (SPL) genomic expression cassette. Four loci in two endogenous genes were targeted by both systems for comparative analysis. Mutations generated by the GSC system were rare in T1 plants but were abundant (30%) in the T2 generation. The vast majority (70%) of the T2 mutant population generated using the UC system were chimeras while the newly developed GSC system produced only 29% chimeras, with 70% of the T2 mutants being heterozygous. Analysis of two loci in the T2 population showed that the abundance of heritable gene mutations was 37% higher in the GSC system compared to the UC system and the level of polymorphism of the mutations was also dramatically increased with the GSC system. Two additional systems based on germ-line-specific promoters (pDD45-GT and pLAT52-GT) were also tested, and one of them was capable of generating heritable homozygous T1 mutant plants. Our results suggest that future application of the described GSC system will facilitate the screening for targeted gene modifications, especially lethal mutations in the T2 population. PMID:26360626

  10. Identifying a novel role for X-prolyl aminopeptidase (Xpnpep) 2 in CrVI-induced adverse effects on germ cell nest breakdown and follicle development in rats.

    PubMed

    Banu, Sakhila K; Stanley, Jone A; Sivakumar, Kirthiram K; Arosh, Joe A; Barhoumi, Rola; Burghardt, Robert C

    2015-03-01

    Environmental exposure to endocrine-disrupting chemicals (EDCs) is one cause of premature ovarian failure (POF). Hexavalent chromium (CrVI) is a heavy metal EDC widely used in more than 50 industries, including chrome plating, welding, wood processing, and tanneries. Recent data from U.S. Environmental Protection Agency indicate increased levels of Cr in drinking water from several American cities, which potentially predispose residents to various health problems. Recently, we demonstrated that gestational exposure to CrVI caused POF in F1 offspring. The current study was performed to identify the molecular mechanism behind CrVI-induced POF. Pregnant rats were treated with 25 ppm of potassium dichromate from Gestational Day (GD) 9.5 to GD 14.5 through drinking water, and the fetuses were exposed to CrVI through transplacental transfer. Ovaries were removed from the fetuses or pups on Embryonic Day (ED) 15.5, ED 17.5, Postnatal Day (PND) 1, PND 4, or PND 25, and various analyses were performed. Results showed that gestational exposure to CrVI: 1) increased germ cell/oocyte apoptosis and advanced germ cell nest (GCN) breakdown; 2) increased X-prolyl aminopeptidase (Xpnpep) 2, a POF marker in humans, during GCN breakdown; 3) decreased Xpnpep2 during postnatal follicle development; and 4) increased colocalization of Xpnpep2 with Col3 and Col4. We also found that Xpnpep2 inversely regulated the expression of Col1, Col3, and Col4 in all the developmental stages studied. Thus, CrVI advanced GCN breakdown and increased follicle atresia in F1 female progeny by targeting Xpnpep2. PMID:25568306

  11. Genetic Mosaics and the Germ Line Lineage

    PubMed Central

    Samuels, Mark E.; Friedman, Jan M.

    2015-01-01

    Genetic mosaics provide information about cellular lineages that is otherwise difficult to obtain, especially in humans. De novo mutations act as cell markers, allowing the tracing of developmental trajectories of all descendants of the cell in which the new mutation arises. De novo mutations may arise at any time during development but are relatively rare. They have usually been observed through medical ascertainment, when the mutation causes unusual clinical signs or symptoms. Mutational events can include aneuploidies, large chromosomal rearrangements, copy number variants, or point mutations. In this review we focus primarily on the analysis of point mutations and their utility in addressing questions of germ line versus somatic lineages. Genetic mosaics demonstrate that the germ line and soma diverge early in development, since there are many examples of combined somatic and germ line mosaicism for de novo mutations. The occurrence of simultaneous mosaicism in both the germ line and soma also shows that the germ line is not strictly clonal but arises from at least two, and possibly multiple, cells in the embryo with different ancestries. Whole genome or exome DNA sequencing technologies promise to expand the range of studies of genetic mosaics, as de novo mutations can now be identified through sequencing alone in the absence of a medical ascertainment. These technologies have been used to study mutation patterns in nuclear families and in monozygotic twins, and in animal model developmental studies, but not yet for extensive cell lineage studies in humans. PMID:25898403

  12. Germ Line Mechanics--And Unfinished Business.

    PubMed

    Wessel, Gary M

    2016-01-01

    Primordial germ cells are usually made early in the development of an organism. These are the mother of all stem cells that are necessary for propagation of the species, yet use highly diverse mechanisms between organisms. How they are specified, and when and where they form, are central to developmental biology. Using diverse organisms to study this development is illuminating for understanding the mechanics these cells use in this essential function and for identifying the breadth of evolutionary changes that have occurred between species. This essay emphasizes how echinoderms may contribute to the patchwork quilt of our understanding of germ line formation during embryogenesis. PMID:26970000

  13. Tooth - abnormal colors

    MedlinePlus

    ... appear as spots or lines in the tooth enamel. Your genes affect your tooth color. Other things ... Infections Inherited diseases may affect the thickness of enamel or the calcium or protein content of the ...

  14. Overview of Tooth Disorders

    MedlinePlus

    ... as when chewing or when tapped by a dental instrument. Pain in a tooth suggests tooth decay or gum ... fractured. Sinus congestion can cause similar symptoms of pain in the area of the upper ... CONSUMERS: ...

  15. Impaired tooth root development after treatment of a cerebellar astrocytoma: A case report

    SciTech Connect

    Eckles, T.A.; Kalkwarf, K.L.

    1989-10-01

    A young man, previously treated by surgical resection of a grade III cerebellar astrocytoma in combination with irradiation and chemotherapy, was found to display severe generalized root agenesis. This patient also exhibited secondary hypothyroidism and decreased levels of growth hormone. These factors are discussed in relation to their possible role in impaired root development.

  16. Fractured tooth (image)

    MedlinePlus

    A tooth can be chipped or fractured during an accident or a bad fall. A tooth that is chipped or not badly fractured can usually be handled on a nonemergency basis. A tooth that is badly fractured may have exposed nerve ...

  17. Mouse tooth development time sequence determination for the ICR/Jcl strain.

    PubMed

    Gaete, Marcia; Lobos, Nelson; Torres-Quintana, María Angélica

    2004-09-01

    To establish the normal dental development pattern of the ICR/Jcl strain of mouse, we analyzed a significant number of observations of the different developmental stages of the first mandibular molar, accurately recording the chronology of their daily embryonic development. Proliferation of the dental sheet began at day 12.5 in utero (E-12.5), the bud stage appeared at days E-13.5 and E-14.5, the cap stage was observed at days E-14.5, E-15.5 and E-16.5 and the early bell stage at day E-17.5. The presence of predentin was observed at day E-18.5 and dentin was observed 1 and 2 days after birth (D-1 and D-2). The late bell stage with presence of enamel was detected more than 3 days after birth. Embryonic and dental development in the ICR/Jcl strain of mouse is faster than in other well-known strains. The establishment of this developmental pattern will be useful for future investigations of transgenic mice. PMID:15508745

  18. Supplemental tooth in primary dentition

    PubMed Central

    Mohan, Ravi Prakash Sasankoti; Verma, Sankalp; Singh, Udita; Agarwal, Neha

    2014-01-01

    An extra tooth causing numerical excess in dentition is described as supernumerary tooth, and the resultant condition is termed as hyperdontia. Hyperdontia is more commonly seen in the permanent dentition than primary one. Supernumerary tooth which resembles tooth shape and supplements for occlusion is called as supplemental tooth. We present a case with supplemental tooth in primary dentition. PMID:24913075

  19. "Life in a Germ-Free World":

    PubMed Central

    Kirk, Robert G. W.

    2012-01-01

    Summary: This article examines a specific technology, the germ-free "isolator," tracing its development across three sites: (1) the laboratory for the production of standard laboratory animals, (2) agriculture for the efficient production of farm animals, and (3) the hospital for the control and prevention of cross-infection and the protection of individuals from infection. Germ-free technology traveled across the laboratory sciences, clinical and veterinary medicine, and industry, yet failed to become institutionalized outside the laboratory. That germ-free technology worked was not at issue. Working, however, was not enough. Examining the history of a technology that failed to find widespread application reveals the labor involved in aligning cultural, societal, and material factors necessary for successful medical innovation. PMID:23000838

  20. Clinical measurement of tooth wear: Tooth wear indices

    PubMed Central

    López-Frías, Francisco J.; Castellanos-Cosano, Lizett; Martín-González, Jenifer; Llamas-Carreras, José M.

    2012-01-01

    Attrition, erosion, and abrasion result in alterations to the tooth and manifest as tooth wear. Each classification corresponds to a different process with specific clinical features. Classifications made so far have no accurate prevalence data because the indexes do not necessarily measure a specific etiology, or because the study populations can be diverse in age and characteristics. Tooth wears (attrition, erosion and abrasion) is perceived internationally as a growing problem. However, the interpretation and comparison of clinical and epidemiological studies, it is increasingly difficult because of differences in terminology and the large number of indicators/indices that have been developed for the diagnosis, classification and monitoring of the loss of dental hard tissue. These indices have been designed to identify increasing severity and are usually numerical, none have universal acceptance, complicating the evaluation of the true increase in prevalence reported. This article considers the ideal requirements for an erosion index. A literature review is conducted with the aim of analyzing the evolution of the indices used today and discuss whether they meet the clinical needs and research in dentistry. Key words:Tooth wear, tooth wear indices, attrition, erosion, abrasion, abfraction. PMID:24558525

  1. Identification of a putative germ plasm in the amphipod Parhyale hawaiensis

    PubMed Central

    2013-01-01

    Background Specification of the germ line is an essential event during the embryonic development of sexually reproducing animals, as germ line cells are uniquely capable of giving rise to the next generation. Animal germ cells arise through either inheritance of a specialized, maternally supplied cytoplasm called 'germ plasm’ or though inductive signaling by somatic cells. Our understanding of germ cell determination is based largely on a small number of model organisms. To better understand the evolution of germ cell specification, we are investigating this process in the amphipod crustacean Parhyale hawaiensis. Experimental evidence from previous studies demonstrated that Parhyale germ cells are specified through inheritance of a maternally supplied cytoplasmic determinant; however, this determinant has not been identified. Results Here we show that the one-cell stage Parhyale embryo has a distinct cytoplasmic region that can be identified by morphology as well as the localization of germ line-associated RNAs. Removal of this cytoplasmic region results in a loss of embryonic germ cells, supporting the hypothesis that it is required for specification of the germ line. Surprisingly, we found that removal of this distinct cytoplasm also results in aberrant somatic cell behaviors, as embryos fail to gastrulate. Conclusions Parhyale hawaiensis embryos have a specialized cytoplasm that is required for specification of the germ line. Our data provide the first functional evidence of a putative germ plasm in a crustacean and provide the basis for comparative functional analysis of germ plasm formation within non-insect arthropods. PMID:24314239

  2. A prospective study on the effectiveness of newly developed autogenous tooth bone graft material for sinus bone graft procedure

    PubMed Central

    Jun, Sang-Ho; Ahn, Jin-Soo; Lee, Jae-Il; Ahn, Kyo-Jin; Yun, Pil-Young

    2014-01-01

    PURPOSE The purpose of this prospective study was to evaluate the effectiveness of newly developed autogenous tooth bone graft material (AutoBT)application for sinus bone graft procedure. MATERIALS AND METHODS The patients with less than 5.0 mm of residual bone height in maxillary posterior area were enrolled. For the sinus bone graft procedure, Bio-Oss was grafted in control group and AutoBT powder was grafted in experimental group. Clinical and radiographic examination were done for the comparison of grafted materials in sinus cavity between groups. At 4 months after sinus bone graft procedure, biopsy specimens were analyzed by microcomputed tomography and histomorphometric examination for the evaluation of healing state of bone graft site. RESULTS In CT evaluation, there was no difference in bone density, bone height and sinus membrane thickness between groups. In microCT analysis, there was no difference in total bone volume, new bone volume, bone mineral density of new bone between groups. There was significant difference trabecular thickness (0.07 µm in Bio-Oss group Vs. 0.08 µm in AutoBT group) (P=.006). In histomorphometric analysis, there was no difference in new bone formation, residual graft material, bone marrow space between groups. There was significant difference osteoid thickness (8.35 µm in Bio-Oss group Vs. 13.12 µm in AutoBT group) (P=.025). CONCLUSION AutoBT could be considered a viable alternative to the autogenous bone or other bone graft materials in sinus bone graft procedure. PMID:25551014

  3. Impact of gin saw tooth design on textile processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toothed gin saws have been used to separate cotton fiber from the seed for over 200 years. There have been many saw tooth designs developed over the years. Most of these designs were developed by trial and error. A complete and scientific analysis of tooth design has never been done. It is not k...

  4. UTILIZING CORN GERM MEAL IN PLYWOOD GLUE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was conducted to evaluate the potential of corn germ meal as protein extender in plywood adhesive. This research is part of our laboratory’s efforts to develop new uses for the proteinaceous co-products from cereal and soybean processing. We were previously successful in formulating a s...

  5. RAN-Binding Protein 9 is Involved in Alternative Splicing and is Critical for Male Germ Cell Development and Male Fertility

    PubMed Central

    Bao, Jianqiang; Tang, Chong; Li, Jiachen; Zhang, Ying; Bhetwal, Bhupal P.; Zheng, Huili; Yan, Wei

    2014-01-01

    As a member of the large Ran-binding protein family, Ran-binding protein 9 (RANBP9) has been suggested to play a critical role in diverse cellular functions in somatic cell lineages in vitro, and this is further supported by the neonatal lethality phenotype in Ranbp9 global knockout mice. However, the exact molecular actions of RANBP9 remain largely unknown. By inactivation of Ranbp9 specifically in testicular somatic and spermatogenic cells, we discovered that Ranbp9 was dispensable for Sertoli cell development and functions, but critical for male germ cell development and male fertility. RIP-Seq and proteomic analyses revealed that RANBP9 was associated with multiple key splicing factors and directly targeted >2,300 mRNAs in spermatocytes and round spermatids. Many of the RANBP9 target and non-target mRNAs either displayed aberrant splicing patterns or were dysregulated in the absence of Ranbp9. Our data uncovered a novel role of Ranbp9 in regulating alternative splicing in spermatogenic cells, which is critical for normal spermatogenesis and male fertility. PMID:25474150

  6. Impacted tooth

    MedlinePlus

    ... usually successful when it does cause symptoms. Wisdom teeth removed before age 20 often have better results. This is because ... easier removal and better healing. As a person ages, the roots ... curved. Bone becomes more rigid and complications can develop.

  7. The proteasome inhibitor bortezomib induces testicular toxicity by upregulation of oxidative stress, AMP-activated protein kinase (AMPK) activation and deregulation of germ cell development in adult murine testis.

    PubMed

    Li, Wei; Fu, Jianfang; Zhang, Shun; Zhao, Jie; Xie, Nianlin; Cai, Guoqing

    2015-06-01

    Understanding how chemotherapeutic agents mediate testicular toxicity is crucial in light of compelling evidence that male infertility, one of the severe late side effects of intensive cancer treatment, occurs more often than they are expected to. Previous study demonstrated that bortezomib (BTZ), a 26S proteasome inhibitor used to treat refractory multiple myeloma (MM), exerts deleterious impacts on spermatogenesis in pubertal mice via unknown mechanisms. Here, we showed that intermittent treatment with BTZ resulted in fertility impairment in adult mice, evidenced by testicular atrophy, desquamation of immature germ cells and reduced caudal sperm storage. These deleterious effects may originate from the elevated apoptosis in distinct germ cells during the acute phase and the subsequent disruption of Sertoli-germ cell anchoring junctions (AJs) during the late recovery. Mechanistically, balance between AMP-activated protein kinase (AMPK) activation and Akt/ERK pathway appeared to be indispensable for AJ integrity during the late testicular recovery. Of particular interest, the upregulated testicular apoptosis and the following disturbance of Sertoli-germ cell interaction may both stem from the excessive oxidative stress elicited by BTZ exposure. We also provided the in vitro evidence that AMPK-dependent mechanisms counteract follicle-stimulating hormone (FSH) proliferative effects in BTZ-exposed Sertoli cells. Collectively, BTZ appeared to efficiently prevent germ cells from normal development via multiple mechanisms in adult mice. Employment of antioxidants and/or AMPK inhibitor may represent an attractive strategy of fertility preservation in male MM patients exposed to conventional BTZ therapy and warrants further investigation. PMID:25886977

  8. The proteasome inhibitor bortezomib induces testicular toxicity by upregulation of oxidative stress, AMP-activated protein kinase (AMPK) activation and deregulation of germ cell development in adult murine testis

    SciTech Connect

    Li, Wei; Fu, Jianfang; Zhang, Shun; Zhao, Jie; Xie, Nianlin; Cai, Guoqing

    2015-06-01

    Understanding how chemotherapeutic agents mediate testicular toxicity is crucial in light of compelling evidence that male infertility, one of the severe late side effects of intensive cancer treatment, occurs more often than they are expected to. Previous study demonstrated that bortezomib (BTZ), a 26S proteasome inhibitor used to treat refractory multiple myeloma (MM), exerts deleterious impacts on spermatogenesis in pubertal mice via unknown mechanisms. Here, we showed that intermittent treatment with BTZ resulted in fertility impairment in adult mice, evidenced by testicular atrophy, desquamation of immature germ cells and reduced caudal sperm storage. These deleterious effects may originate from the elevated apoptosis in distinct germ cells during the acute phase and the subsequent disruption of Sertoli–germ cell anchoring junctions (AJs) during the late recovery. Mechanistically, balance between AMP-activated protein kinase (AMPK) activation and Akt/ERK pathway appeared to be indispensable for AJ integrity during the late testicular recovery. Of particular interest, the upregulated testicular apoptosis and the following disturbance of Sertoli–germ cell interaction may both stem from the excessive oxidative stress elicited by BTZ exposure. We also provided the in vitro evidence that AMPK-dependent mechanisms counteract follicle-stimulating hormone (FSH) proliferative effects in BTZ-exposed Sertoli cells. Collectively, BTZ appeared to efficiently prevent germ cells from normal development via multiple mechanisms in adult mice. Employment of antioxidants and/or AMPK inhibitor may represent an attractive strategy of fertility preservation in male MM patients exposed to conventional BTZ therapy and warrants further investigation. - Highlights: • Intermittent treatment with BTZ caused fertility impairment in adult mice. • BTZ treatment elicited apoptosis during early phase of testicular recovery. • Up-regulation of oxidative stress by BTZ treatment

  9. Ion channels, channelopathies, and tooth formation.

    PubMed

    Duan, X

    2014-02-01

    The biological functions of ion channels in tooth development vary according to the nature of their gating, the species of ions passing through those gates, the number of gates, localization of channels, tissue expressing the channel, and interactions between cells and microenvironment. Ion channels feature unique and specific ion flux in ameloblasts, odontoblasts, and other tooth-specific cell lineages. Both enamel and dentin have active chemical systems orchestrating a variety of ion exchanges and demineralization and remineralization processes in a stage-dependent manner. An important role for ion channels is to regulate and maintain the calcium and pH homeostasis that are critical for proper enamel and dentin biomineralization. Specific functions of chloride channels, TRPVs, calcium channels, potassium channels, and solute carrier superfamily members in tooth formation have been gradually clarified in recent years. Mutations in these ion channels or transporters often result in disastrous changes in tooth development. The channelopathies of tooth include altered eruption (CLCN7, KCNJ2, TRPV3), root dysplasia (CLCN7, KCNJ2), amelogenesis imperfecta (KCNJ1, CFTR, AE2, CACNA1C, GJA1), dentin dysplasia (CLCN5), small teeth (CACNA1C, GJA1), tooth agenesis (CLCN7), and other impairments. The mechanisms leading to tooth channelopathies are primarily related to pH regulation, calcium homeostasis, or other alterations of the niche for tooth eruption and development. PMID:24076519

  10. Regenerative Applications Using Tooth Derived Stem Cells in Other Than Tooth Regeneration: A Literature Review

    PubMed Central

    Park, Yun-Jong; Cha, Seunghee; Park, Young-Seok

    2016-01-01

    Tooth derived stem cells or dental stem cells are categorized according to the location from which they are isolated and represent a promising source of cells for regenerative medicine. Originally, as one kind of mesenchymal stem cells, they are considered an alternative of bone marrow stromal cells. They share many commonalties but maintain differences. Considering their original function in development and the homeostasis of tooth structures, many applications of these cells in dentistry have aimed at tooth structure regeneration; however, the application in other than tooth structures has been attempted extensively. The availability from discarded or removed teeth can be an innate benefit as a source of autologous cells. Their origin from the neural crest results in exploitation of neurological and numerous other applications. This review briefly highlights current and future perspectives of the regenerative applications of tooth derived stem cells in areas beyond tooth regeneration. PMID:26798366