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Sample records for basic helix-loop-helix protein-mediated

  1. A Classification of Basic Helix-Loop-Helix Transcription Factors of Soybean

    PubMed Central

    Hudson, Karen A.; Hudson, Matthew E.

    2015-01-01

    The complete genome sequence of soybean allows an unprecedented opportunity for the discovery of the genes controlling important traits. In particular, the potential functions of regulatory genes are a priority for analysis. The basic helix-loop-helix (bHLH) family of transcription factors is known to be involved in controlling a wide range of systems critical for crop adaptation and quality, including photosynthesis, light signalling, pigment biosynthesis, and seed pod development. Using a hidden Markov model search algorithm, 319 genes with basic helix-loop-helix transcription factor domains were identified within the soybean genome sequence. These were classified with respect to their predicted DNA binding potential, intron/exon structure, and the phylogeny of the bHLH domain. Evidence is presented that the vast majority (281) of these 319 soybean bHLH genes are expressed at the mRNA level. Of these soybean bHLH genes, 67% were found to exist in two or more homeologous copies. This dataset provides a framework for future studies on bHLH gene function in soybean. The challenge for future research remains to define functions for the bHLH factors encoded in the soybean genome, which may allow greater flexibility for genetic selection of growth and environmental adaptation in this widely grown crop. PMID:25763382

  2. Basic helix-loop-helix transcription factors and epidermal cell fate determination in Arabidopsis

    PubMed Central

    Zhao, Hongtao; Li, Xia; Ma, Ligeng

    2012-01-01

    Cell fate determination is an important process in multicellular organisms. Plant epidermis is a readily-accessible, well-used model for the study of cell fate determination. Our knowledge of cell fate determination is growing steadily due to genetic and molecular analyses of root hairs, trichomes, and stomata, which are derived from the epidermal cells of roots and aerial tissues. Studies have shown that a large number of factors are involved in the establishment of these cell types, especially members of the basic helix-loop-helix (bHLH) superfamily, which is an important family of transcription factors. In this mini-review, we focus on the role of bHLH transcription factors in cell fate determination in Arabidopsis. PMID:23073001

  3. The Basic Helix-Loop-Helix Transcription Factor PIF5 Acts on Ethylene Biosynthesis and Phytochrome Signaling by Distinct Mechanisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    HYTOCHROME-INTERACTING FACTOR5 (PIF5), a basic helix-loop-helix transcription factor, interacts specifically with the photoactivated form of phytochrome B (phyB). Here, we report that dark-grown Arabidopsis thaliana seedlings overexpressing PIF5 (PIF5-OX) exhibit exaggerated apical hooks and short h...

  4. The basic helix-loop-helix transcription factor, Mist1, induces maturation of mouse fetal hepatoblasts.

    PubMed

    Chikada, Hiromi; Ito, Keiichi; Yanagida, Ayaka; Nakauchi, Hiromitsu; Kamiya, Akihide

    2015-01-01

    Hepatic stem/progenitor cells, hepatoblasts, have a high proliferative ability and can differentiate into mature hepatocytes and cholangiocytes. Therefore, these cells are considered to be useful for regenerative medicine and drug screening for liver diseases. However, it is problem that in vitro maturation of hepatoblasts is insufficient in the present culture system. In this study, a novel regulator to induce hepatic differentiation was identified and the molecular function of this factor was examined in embryonic day 13 hepatoblast culture with maturation factor, oncostatin M and extracellular matrices. Overexpression of the basic helix-loop-helix type transcription factor, Mist1, induced expression of mature hepatocytic markers such as carbamoyl-phosphate synthetase1 and several cytochrome P450 (CYP) genes in this culture system. In contrast, Mist1 suppressed expression of cholangiocytic markers such as Sox9, Sox17, Ck19, and Grhl2. CYP3A metabolic activity was significantly induced by Mist1 in this hepatoblast culture. In addition, Mist1 induced liver-enriched transcription factors, CCAAT/enhancer-binding protein α and Hepatocyte nuclear factor 1α, which are known to be involved in liver functions. These results suggest that Mist1 partially induces mature hepatocytic expression and function accompanied by the down-regulation of cholangiocytic markers. PMID:26456005

  5. Basic helix-loop-helix transcription factor gene family phylogenetics and nomenclature.

    PubMed

    Skinner, Michael K; Rawls, Alan; Wilson-Rawls, Jeanne; Roalson, Eric H

    2010-07-01

    A phylogenetic analysis of the basic helix-loop-helix (bHLH) gene superfamily was performed using seven different species (human, mouse, rat, worm, fly, yeast, and plant Arabidopsis) and involving over 600 bHLH genes (Stevens et al., 2008). All bHLH genes were identified in the genomes of the various species, including expressed sequence tags, and the entire coding sequence was used in the analysis. Nearly 15% of the gene family has been updated or added since the original publication. A super-tree involving six clades and all structural relationships was established and is now presented for four of the species. The wealth of functional data available for members of the bHLH gene superfamily provides us with the opportunity to use this exhaustive phylogenetic tree to predict potential functions of uncharacterized members of the family. This phylogenetic and genomic analysis of the bHLH gene family has revealed unique elements of the evolution and functional relationships of the different genes in the bHLH gene family. PMID:20219281

  6. Origin and Diversification of Basic-Helix-Loop-Helix Proteins in Plants

    PubMed Central

    Pires, Nuno; Dolan, Liam

    2010-01-01

    Basic helix-loop-helix (bHLH) proteins are a class of transcription factors found throughout eukaryotic organisms. Classification of the complete sets of bHLH proteins in the sequenced genomes of Arabidopsis thaliana and Oryza sativa (rice) has defined the diversity of these proteins among flowering plants. However, the evolutionary relationships of different plant bHLH groups and the diversity of bHLH proteins in more ancestral groups of plants are currently unknown. In this study, we use whole-genome sequences from nine species of land plants and algae to define the relationships between these proteins in plants. We show that few (less than 5) bHLH proteins are encoded in the genomes of chlorophytes and red algae. In contrast, many bHLH proteins (100–170) are encoded in the genomes of land plants (embryophytes). Phylogenetic analyses suggest that plant bHLH proteins are monophyletic and constitute 26 subfamilies. Twenty of these subfamilies existed in the common ancestors of extant mosses and vascular plants, whereas six further subfamilies evolved among the vascular plants. In addition to the conserved bHLH domains, most subfamilies are characterized by the presence of highly conserved short amino acid motifs. We conclude that much of the diversity of plant bHLH proteins was established in early land plants, over 440 million years ago. PMID:19942615

  7. The basic helix-loop-helix transcription factor, Mist1, induces maturation of mouse fetal hepatoblasts

    PubMed Central

    Chikada, Hiromi; Ito, Keiichi; Yanagida, Ayaka; Nakauchi, Hiromitsu; Kamiya, Akihide

    2015-01-01

    Hepatic stem/progenitor cells, hepatoblasts, have a high proliferative ability and can differentiate into mature hepatocytes and cholangiocytes. Therefore, these cells are considered to be useful for regenerative medicine and drug screening for liver diseases. However, it is problem that in vitro maturation of hepatoblasts is insufficient in the present culture system. In this study, a novel regulator to induce hepatic differentiation was identified and the molecular function of this factor was examined in embryonic day 13 hepatoblast culture with maturation factor, oncostatin M and extracellular matrices. Overexpression of the basic helix-loop-helix type transcription factor, Mist1, induced expression of mature hepatocytic markers such as carbamoyl-phosphate synthetase1 and several cytochrome P450 (CYP) genes in this culture system. In contrast, Mist1 suppressed expression of cholangiocytic markers such as Sox9, Sox17, Ck19, and Grhl2. CYP3A metabolic activity was significantly induced by Mist1 in this hepatoblast culture. In addition, Mist1 induced liver-enriched transcription factors, CCAAT/enhancer-binding protein α and Hepatocyte nuclear factor 1α, which are known to be involved in liver functions. These results suggest that Mist1 partially induces mature hepatocytic expression and function accompanied by the down-regulation of cholangiocytic markers. PMID:26456005

  8. Regulation of Arabidopsis Brassinosteroid Signaling by Atypical Basic Helix-Loop-Helix Proteins[C][W

    PubMed Central

    Wang, Hao; Zhu, Yongyou; Fujioka, Shozo; Asami, Tadao; Li, Jiayang; Li, Jianming

    2009-01-01

    Basic helix-loop-helix (bHLH) proteins are highly conserved transcription factors critical for cell proliferation and differentiation. Recent studies have implicated bHLH proteins in many plant signaling processes, including brassinosteroid (BR) signaling. Here, we report identification of two families of atypical bHLH proteins capable of modulating BR signaling. We found that activation-tagged bri1 suppressor 1-Dominant (atbs1-D), previously identified as a dominant suppressor of a weak BR receptor mutant bri1-301, was caused by overexpression of a 93–amino acid atypical bHLH protein lacking amino acids critical for DNA binding. Interestingly, atbs1-D only suppresses weak BR mutants, while overexpression of a truncated ATBS1 lacking the basic motif also rescues bri1-301, suggesting that ATBS1 likely stimulates BR signaling by sequestering negative BR signaling components. A yeast two-hybrid screen using ATBS1 as bait discovered four ATBS1-Interacting Factors (AIFs) that are members of another atypical bHLH protein subfamily. AIF1 exhibits an overlapping expression pattern with ATBS1 and its homologs and interacts with ATBS1 in vitro and in vivo. AIF1 overexpression nullifies the suppressive effect of atbs1-D on bri1-301 and results in dwarf transgenic plants resembling BR mutants. By contrast, silencing of AIF1 partially suppressed the bri1-301 phenotype. Our results suggested that plants use these atypical bHLH proteins to regulate BR signaling. PMID:20023194

  9. Regulatory module network of basic/helix-loop-helix transcription factors in mouse brain

    PubMed Central

    Li, Jing; Liu, Zijing J; Pan, Yuchun C; Liu, Qi; Fu, Xing; Cooper, Nigel GF; Li, Yixue; Qiu, Mengsheng; Shi, Tieliu

    2007-01-01

    Background The basic/helix-loop-helix (bHLH) proteins are important components of the transcriptional regulatory network, controlling a variety of biological processes, especially the development of the central nervous system. Until now, reports describing the regulatory network of the bHLH transcription factor (TF) family have been scarce. In order to understand the regulatory mechanisms of bHLH TFs in mouse brain, we inferred their regulatory network from genome-wide gene expression profiles with the module networks method. Results A regulatory network comprising 15 important bHLH TFs and 153 target genes was constructed. The network was divided into 28 modules based on expression profiles. A regulatory-motif search shows the complexity and diversity of the network. In addition, 26 cooperative bHLH TF pairs were also detected in the network. This cooperation suggests possible physical interactions or genetic regulation between TFs. Interestingly, some TFs in the network regulate more than one module. A novel cross-repression between Neurod6 and Hey2 was identified, which may control various functions in different brain regions. The presence of TF binding sites (TFBSs) in the promoter regions of their target genes validates more than 70% of TF-target gene pairs of the network. Literature mining provides additional support for five modules. More importantly, the regulatory relationships among selected key components are all validated in mutant mice. Conclusion Our network is reliable and very informative for understanding the role of bHLH TFs in mouse brain development and function. It provides a framework for future experimental analyses. PMID:18021424

  10. Phylogenetic analyses of vector mosquito basic helix-loop-helix transcription factors.

    PubMed

    Zhang, D B; Wang, Y; Liu, A K; Wang, X H; Dang, C W; Yao, Q; Chen, K P

    2013-10-01

    Basic helix-loop-helix (bHLH) transcription factors play critical roles in the regulation of a wide range of developmental processes in higher organisms and have been identified in more than 20 organisms. Mosquitoes are important vectors of certain human diseases. In this study, Aedes aegypti, Anopheles gambiae str. PEST and Culex quinquefasciatus genomes were found to encode 55, 55 and 57 bHLH genes, respectively. Further phylogenetic analyses and OrthoDB and Kyoto encyclopedia of genes and genomes orthology database searches led us to define orthology for all the identified mosquito bHLHs successfully. This provides useful information with which to update annotations to 40 Ae. aegypti, 55 An. gambiae and 38 C. quinquefasciatus bHLH genes in VectorBase. The mosquito lineage has more bHLH genes in the Atonal, neurogenin (Ngn) and Hes-related with YRPW motif (Hey) families than do other insect species, suggesting that mosquitoes have evolved to be more sensitive to vibration, light and chemicals. Mosquito bHLH genes generally have higher evolutionary rates than other insect species. However, no pervasive positive selection occurred in the evolution of insect bHLH genes. Only episodic positive selection was found to affect evolution of bHLH genes in 11 families. Besides, coding regions of several Ae. aegypti bHLH motifs have unusually long introns in which multiple copies of transposable elements have been identified. These data provide a solid basis for further studies on structures and functions of bHLH proteins in the regulation of mosquito development and for prevention and control of mosquito-mediated human diseases. PMID:23906262

  11. A basic helix-loop-helix transcription factor, PhFBH4, regulates flower senescence by modulating ethylene biosynthesis pathway in petunia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The basic helix-loop-helix (bHLH) transcription factors (TFs) play important roles in regulating multiple biological processes in plants. However, there are few reports about the function of bHLHs in flower senescence. In this study, a bHLH TF, PhFBH4, was found to be dramatically upregulated during...

  12. A novel basic helix-loop-helix protein is expressed in muscle attachment sites of the Drosophila epidermis.

    PubMed Central

    Armand, P; Knapp, A C; Hirsch, A J; Wieschaus, E F; Cole, M D

    1994-01-01

    We have found that a novel basic helix-loop-helix (bHLH) protein is expressed almost exclusively in the epidermal attachments sites for the somatic muscles of Drosophila melanogaster. A Drosophila cDNA library was screened with radioactively labeled E12 protein, which can dimerize with many HLH proteins. One clone that emerged from this screen encoded a previously unknown protein of 360 amino acids, named delilah, that contains both basic and HLH domains, similar to a group of cellular transcription factors implicated in cell type determination. Delilah protein formed heterodimers with E12 that bind to the muscle creatine kinase promoter. In situ hybridization with the delilah cDNA localized the expression of the gene to a subset of cells in the epidermis which form a distinct pattern involving both the segmental boundaries and intrasegmental clusters. This pattern was coincident with the known sites of attachment of the somatic muscles to tendon cells in the epidermis. delilah expression persists in snail mutant embryos which lack mesoderm, indicating that expression of the gene was not induced by attachment of the underlying muscles. The similarity of this gene to other bHLH genes suggests that it plays an important role in the differentiation of epidermal cells into muscle attachment sites. Images PMID:8196652

  13. Genome-wide features of neuroendocrine regulation in Drosophila by the basic helix-loop-helix transcription factor DIMMED

    PubMed Central

    Hadžić, Tarik; Park, Dongkook; Abruzzi, Katharine C.; Yang, Lin; Trigg, Jennifer S.; Rohs, Remo; Rosbash, Michael; Taghert, Paul H.

    2015-01-01

    Neuroendocrine (NE) cells use large dense core vesicles (LDCVs) to traffic, process, store and secrete neuropeptide hormones through the regulated secretory pathway. The dimmed (DIMM) basic helix-loop-helix transcription factor of Drosophila controls the level of regulated secretory activity in NE cells. To pursue its mechanisms, we have performed two independent genome-wide analyses of DIMM's activities: (i) in vivo chromatin immunoprecipitation (ChIP) to define genomic sites of DIMM occupancy and (ii) deep sequencing of purified DIMM neurons to characterize their transcriptional profile. By this combined approach, we showed that DIMM binds to conserved E-boxes in enhancers of 212 genes whose expression is enriched in DIMM-expressing NE cells. DIMM binds preferentially to certain E-boxes within first introns of specific gene isoforms. Statistical machine learning revealed that flanking regions of putative DIMM binding sites contribute to its DNA binding specificity. DIMM's transcriptional repertoire features at least 20 LDCV constituents. In addition, DIMM notably targets the pro-secretory transcription factor, creb-A, but significantly, DIMM does not target any neuropeptide genes. DIMM therefore prescribes the scale of secretory activity in NE neurons, by a systematic control of both proximal and distal points in the regulated secretory pathway. PMID:25634895

  14. Selective utilization of basic helix-loop-helix-leucine zipper proteins at the immunoglobulin heavy-chain enhancer.

    PubMed

    Carter, R S; Ordentlich, P; Kadesch, T

    1997-01-01

    The microE3 E box within the immunoglobulin heavy-chain (IgH) enhancer binds several proteins of the basic helix-loop-helix-leucine zipper (bHLHzip) class, including TFE3, USF1, and Max. Both TFE3 and USF have been described as transcriptional activators, and so we investigated their possible roles in activating the IgH enhancer in vivo. Although TFE3 activated various enhancer-based reporters, both USF1 and Max effectively inhibited transcription. Inhibition by USF correlated with the lack of a strong activation domain and was the result of the protein neutralizing the microE3 site. The effects of dominant-negative derivatives of TFE3 and USF1 confirmed that TFE3, or a TFE3-like protein, is the primary cellular bHLHzip protein that activates the IgH enhancer. In addition to providing a physiological role for TFE3, our results call into question the traditional view of USF1 as an obligate transcriptional activator. PMID:8972181

  15. GLABRA2 Directly Suppresses Basic Helix-Loop-Helix Transcription Factor Genes with Diverse Functions in Root Hair Development

    PubMed Central

    Lin, Qing; Ohashi, Yohei; Kato, Mariko; Tsuge, Tomohiko; Gu, Hongya; Qu, Li-Jia; Aoyama, Takashi

    2015-01-01

    The Arabidopsis thaliana GLABRA2 (GL2) gene encodes a transcription factor involved in the cell differentiation of various epidermal tissues. During root hair pattern formation, GL2 suppresses root hair development in non-hair cells, acting as a node between the gene regulatory networks for cell fate determination and cell differentiation. Despite the importance of GL2 function, its molecular basis remains obscure because the GL2 target genes leading to the network for cell differentiation are unknown. We identified five basic helix-loop-helix (bHLH) transcription factor genes—ROOT HAIR DEFECTIVE6 (RHD6), RHD6-LIKE1 (RSL1), RSL2, LjRHL1-LIKE1 (LRL1), and LRL2—as GL2 direct targets using transcriptional and post-translational induction systems. Chromatin immunoprecipitation analysis confirmed GL2 binding to upstream regions of these genes in planta. Reporter gene analyses showed that these genes are expressed in various stages of root hair development and are suppressed by GL2 in non-hair cells. GL2 promoter-driven green fluorescent protein fusions of LRL1 and LRL2, but not those of the other bHLH proteins, conferred root hair development on non-hair cells. These results indicate that GL2 directly suppresses bHLH genes with diverse functions in root hair development. PMID:26486447

  16. Conservation of lotus and Arabidopsis basic helix-loop-helix proteins reveals new players in root hair development.

    PubMed

    Karas, Bogumil; Amyot, Lisa; Johansen, Christopher; Sato, Shusei; Tabata, Satoshi; Kawaguchi, Masayoshi; Szczyglowski, Krzysztof

    2009-11-01

    Basic helix-loop-helix (bHLH) proteins constitute a large family of transcriptional regulators in plants. Although they have been shown to play important roles in a wide variety of developmental processes, relatively few have been functionally characterized. Here, we describe the map-based cloning of the Lotus japonicus ROOTHAIRLESS1 (LjRHL1) locus. Deleterious mutations in this locus prevent root hair development, which also aborts root hair-dependent colonization of the host root by nitrogen-fixing bacteria. We show that the LjRHL1 gene encodes a presumed bHLH transcription factor that functions in a nonredundant manner to control root hair development in L. japonicus. Homology search and cross-species complementation experiments defined three members of the Arabidopsis (Arabidopsis thaliana) bHLH protein family, At2g24260, At4g30980, and At5g58010, as functionally equivalent to LjRHL1. Curiously, At2g24260 and At4g30980 mRNA species accumulate independently from the known positive regulators of root hair cell fate, while all three genes act in a partially redundant manner to regulate root hair development in Arabidopsis. PMID:19675148

  17. Genome-Wide Analysis of Basic/Helix-Loop-Helix Transcription Factor Family in Rice and Arabidopsis1[W

    PubMed Central

    Li, Xiaoxing; Duan, Xuepeng; Jiang, Haixiong; Sun, Yujin; Tang, Yuanping; Yuan, Zheng; Guo, Jingkang; Liang, Wanqi; Chen, Liang; Yin, Jingyuan; Ma, Hong; Wang, Jian; Zhang, Dabing

    2006-01-01

    The basic/helix-loop-helix (bHLH) transcription factors and their homologs form a large family in plant and animal genomes. They are known to play important roles in the specification of tissue types in animals. On the other hand, few plant bHLH proteins have been studied functionally. Recent completion of whole genome sequences of model plants Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) allows genome-wide analysis and comparison of the bHLH family in flowering plants. We have identified 167 bHLH genes in the rice genome, and their phylogenetic analysis indicates that they form well-supported clades, which are defined as subfamilies. In addition, sequence analysis of potential DNA-binding activity, the sequence motifs outside the bHLH domain, and the conservation of intron/exon structural patterns further support the evolutionary relationships among these proteins. The genome distribution of rice bHLH genes strongly supports the hypothesis that genome-wide and tandem duplication contributed to the expansion of the bHLH gene family, consistent with the birth-and-death theory of gene family evolution. Bioinformatics analysis suggests that rice bHLH proteins can potentially participate in a variety of combinatorial interactions, endowing them with the capacity to regulate a multitude of transcriptional programs. In addition, similar expression patterns suggest functional conservation between some rice bHLH genes and their close Arabidopsis homologs. PMID:16896230

  18. The basic helix loop helix transcription factor Twist1 is a novel regulator of ATF4 in osteoblasts.

    PubMed

    Danciu, Theodora E; Li, Yan; Koh, Amy; Xiao, Guozhi; McCauley, Laurie K; Franceschi, Renny T

    2012-01-01

    Parathyroid hormone (PTH) is an essential regulator of endochondral bone formation and an important anabolic agent for the reversal of bone loss. PTH mediates its functions in part by regulating binding of the bone-related activating transcription factor 4 (ATF4) to the osteoblast-specific gene, osteocalcin. The basic helix-loop-helix (bHLH) factors Twist1 and Twist2 also regulate osteocalcin transcription in part through the interaction of the C-terminal "box" domain in these factors and Runx2. In this study, we discovered a novel function of PTH: its ability to dramatically decrease Twist1 transcription. Since ATF4 is a major regulator of the PTH response in osteoblasts, we assessed the mutual regulation between these factors and determined that Twist proteins and ATF4 physically interact in a manner that affects ATF4 DNA binding function. We mapped the interaction domain of Twist proteins to the C-terminal "box" domain and of ATF4, to the N-terminus. Furthermore, we demonstrate that Twist1 overexpression in osteoblasts attenuates ATF4 binding to the osteocalcin promoter in response to PTH. This study thus identifies Twist proteins as novel inhibitory binding partners of ATF4 and explores the functional significance of this interaction. PMID:21866569

  19. The basic helix loop helix transcription factor Twist1 is a novel regulator of ATF4 in osteoblasts

    PubMed Central

    Danciu, Theodora E.; Li, Yan; Koh, Amy; Xiao, Guozhi; McCauley, Laurie K.; Franceschi, Renny T.

    2011-01-01

    Parathyroid hormone (PTH) is an essential regulator of endochondral bone formation and an important anabolic agent for the reversal of bone loss. PTH mediates its functions in part by regulating binding of the bone-related activating transcription factor 4 (ATF4) to the osteoblast-specific gene, osteocalcin. The basic helix-loop-helix (bHLH) factors Twist1 and Twist2 also regulate osteocalcin transcription in part through the interaction of the C-terminal “box” domain in these factors and Runx2. In this study, we discovered a novel function of PTH: its ability to dramatically decrease Twist1 transcription. Since ATF4 is a major regulator of the PTH response in osteoblasts, we assessed the mutual regulation between these factors and determined that Twist proteins and ATF4 physically interact in a manner that affects ATF4 DNA binding function. We mapped the interaction domain of Twist proteins to the C-terminal “box” domain and of ATF4, to the N-terminus. Furthermore, we demonstrate that Twist1 overexpression in osteoblasts attenuates ATF4 binding to the osteocalcin promoter in response to PTH. This study thus identifies Twist proteins as novel inhibitory binding partners of ATF4 and explores the functional significance of this interaction. PMID:21866569

  20. Phylogeny, Functional Annotation, and Protein Interaction Network Analyses of the Xenopus tropicalis Basic Helix-Loop-Helix Transcription Factors

    PubMed Central

    Chen, Deyu

    2013-01-01

    The previous survey identified 70 basic helix-loop-helix (bHLH) proteins, but it was proved to be incomplete, and the functional information and regulatory networks of frog bHLH transcription factors were not fully known. Therefore, we conducted an updated genome-wide survey in the Xenopus tropicalis genome project databases and identified 105 bHLH sequences. Among the retrieved 105 sequences, phylogenetic analyses revealed that 103 bHLH proteins belonged to 43 families or subfamilies with 46, 26, 11, 3, 15, and 4 members in the corresponding supergroups. Next, gene ontology (GO) enrichment analyses showed 65 significant GO annotations of biological processes and molecular functions and KEGG pathways counted in frequency. To explore the functional pathways, regulatory gene networks, and/or related gene groups coding for Xenopus tropicalis bHLH proteins, the identified bHLH genes were put into the databases KOBAS and STRING to get the signaling information of pathways and protein interaction networks according to available public databases and known protein interactions. From the genome annotation and pathway analysis using KOBAS, we identified 16 pathways in the Xenopus tropicalis genome. From the STRING interaction analysis, 68 hub proteins were identified, and many hub proteins created a tight network or a functional module within the protein families. PMID:24312906

  1. A genome-wide identification of basic helix-loop-helix motifs in Pediculus humanus corporis (Phthiraptera: Pediculidae).

    PubMed

    Wang, Xu-Hua; Wang, Yong; Zhang, De-Bao; Liu, A-Ke; Yao, Qin; Chen, Ke-Ping

    2014-01-01

    Basic helix-loop-helix (bHLH) proteins comprise a large superfamily of transcription factors, which are involved in the regulation of various developmental processes. bHLH family members are widely distributed in various eukaryotes including yeast, fruit fly, zebrafish, mouse, and human. In this study, we identified 55 bHLH motifs encoded in genome sequence of the human body louse, Pediculus humanus corporis (Phthiraptera: Pediculidae). Phylogenetic analyses of the identified P. humanus corporis bHLH (PhcbHLH) motifs revealed that there are 23, 11, 9, 1, 10, and 1 member(s) in groups A, B, C, D, E, and F, respectively. Examination to GenBank annotations of the 55 PhcbHLH members indicated that 29 PhcbHLH proteins were annotated in consistence with our analytical result, 8 were annotated different with our analytical result, 12 were merely annotated as hypothetical protein, and the rest 6 were not deposited in GenBank. A comparison on insect bHLH gene composition revealed that human body louse possibly has more hairy and E(spl) genes than other insect species. Because hairy and E(spl) genes have been found to negatively regulate the differentiation of insect preneural cells, it is suggested that the existence of additional hairy and E(spl) genes in human body louse is probably the consequence of its long period adaptation to the relatively dark and stable environment. These data provide good references for further studies on regulatory functions of bHLH proteins in the growth and development of human body louse. PMID:25434030

  2. The Basic/Helix-Loop-Helix Protein Family in Gossypium: Reference Genes and Their Evolution during Tetraploidization

    PubMed Central

    Yan, Qian; Liu, Hou-Sheng; Yao, Dan; Li, Xin; Chen, Han; Dou, Yang; Wang, Yi; Pei, Yan; Xiao, Yue-Hua

    2015-01-01

    Basic/helix-loop-helix (bHLH) proteins comprise one of the largest transcription factor families and play important roles in diverse cellular and molecular processes. Comprehensive analyses of the composition and evolution of the bHLH family in cotton are essential to elucidate their functions and the molecular basis of cotton development. By searching bHLH homologous genes in sequenced diploid cotton genomes (Gossypium raimondii and G. arboreum), a set of cotton bHLH reference genes containing 289 paralogs were identified and named as GobHLH001-289. Based on their phylogenetic relationships, these cotton bHLH proteins were clustered into 27 subfamilies. Compared to those in Arabidopsis and cacao, cotton bHLH proteins generally increased in number, but unevenly in different subfamilies. To further uncover evolutionary changes of bHLH genes during tetraploidization of cotton, all genes of S5a and S5b subfamilies in upland cotton and its diploid progenitors were cloned and compared, and their transcript profiles were determined in upland cotton. A total of 10 genes of S5a and S5b subfamilies (doubled from A- and D-genome progenitors) maintained in tetraploid cottons. The major sequence changes in upland cotton included a 15-bp in-frame deletion in GhbHLH130D and a long terminal repeat retrotransposon inserted in GhbHLH062A, which eliminated GhbHLH062A expression in various tissues. The S5a and S5b bHLH genes of A and D genomes (except GobHLH062) showed similar transcription patterns in various tissues including roots, stems, leaves, petals, ovules, and fibers, while the A- and D-genome genes of GobHLH110 and GobHLH130 displayed clearly different transcript profiles during fiber development. In total, this study represented a genome-wide analysis of cotton bHLH family, and revealed significant changes in sequence and expression of these genes in tetraploid cottons, which paved the way for further functional analyses of bHLH genes in the cotton genus. PMID:25992947

  3. The Basic/Helix-Loop-Helix Protein Family in Gossypium: Reference Genes and Their Evolution during Tetraploidization.

    PubMed

    Yan, Qian; Liu, Hou-Sheng; Yao, Dan; Li, Xin; Chen, Han; Dou, Yang; Wang, Yi; Pei, Yan; Xiao, Yue-Hua

    2015-01-01

    Basic/helix-loop-helix (bHLH) proteins comprise one of the largest transcription factor families and play important roles in diverse cellular and molecular processes. Comprehensive analyses of the composition and evolution of the bHLH family in cotton are essential to elucidate their functions and the molecular basis of cotton development. By searching bHLH homologous genes in sequenced diploid cotton genomes (Gossypium raimondii and G. arboreum), a set of cotton bHLH reference genes containing 289 paralogs were identified and named as GobHLH001-289. Based on their phylogenetic relationships, these cotton bHLH proteins were clustered into 27 subfamilies. Compared to those in Arabidopsis and cacao, cotton bHLH proteins generally increased in number, but unevenly in different subfamilies. To further uncover evolutionary changes of bHLH genes during tetraploidization of cotton, all genes of S5a and S5b subfamilies in upland cotton and its diploid progenitors were cloned and compared, and their transcript profiles were determined in upland cotton. A total of 10 genes of S5a and S5b subfamilies (doubled from A- and D-genome progenitors) maintained in tetraploid cottons. The major sequence changes in upland cotton included a 15-bp in-frame deletion in GhbHLH130D and a long terminal repeat retrotransposon inserted in GhbHLH062A, which eliminated GhbHLH062A expression in various tissues. The S5a and S5b bHLH genes of A and D genomes (except GobHLH062) showed similar transcription patterns in various tissues including roots, stems, leaves, petals, ovules, and fibers, while the A- and D-genome genes of GobHLH110 and GobHLH130 displayed clearly different transcript profiles during fiber development. In total, this study represented a genome-wide analysis of cotton bHLH family, and revealed significant changes in sequence and expression of these genes in tetraploid cottons, which paved the way for further functional analyses of bHLH genes in the cotton genus. PMID:25992947

  4. Role of the basic helix-loop-helix protein ITF2 in the hormonal regulation of Sertoli cell differentiation.

    PubMed

    Muir, Terla; Sadler-Riggleman, Ingrid; Stevens, Jeffrey D; Skinner, Michael K

    2006-04-01

    Sertoli cells are a post-mitotic terminally differentiated cell population that forms the seminiferous tubules in the adult testis and provides the microenvironment and structural support for developing germ cells. During pubertal development, Sertoli cells are responsive to follicle-stimulating hormone (FSH) to promote the expression of differentiated gene products. The basic helix-loop-helix (bHLH) and inhibitors of differentiation (Id) transcription factors are involved in the differentiation of a variety of cell lineages during development. Both bHLH and Id transcription factors have been identified in Sertoli cells. A yeast two-hybrid screen was conducted using a rat Sertoli cell cDNA library to identify bHLH dimerization partners for the Id1 transcription factor. The ubiquitous bHLH protein ITF2 (i.e., E2-2) was identified as one of the interacting partners. The current study investigates the expression and function of ITF2 in Sertoli cells. ITF2 was found to be ubiquitously expressed in all testicular cell types including germ cells, peritubular myoid cells, and Sertoli cells. Stimulation of cultured Sertoli cells with FSH or dibutryl cAMP resulted in a transient decrease in expression of ITF2 mRNA levels followed by a rise in expression with FSH treatment. ITF2 expression was at its highest in mid-pubertal 20-day-old rat Sertoli cells. ITF2 was found to directly bind to negative acting Id HLH proteins and positive acting bHLH proteins such as scleraxis. Transient overexpression of ITF2 protein in cultured Sertoli cells stimulated transferrin promoter activity, which is a marker of Sertoli cell differentiation. Co-transfections of ITF2 and Id proteins sequestered the inhibitory effects of the Id family of proteins. Observations suggest ITF2 can enhance FSH actions through suppressing the inhibitory actions of the Id family of proteins and increasing the actions of stimulatory bHLH proteins (i.e., scleraxis) in Sertoli cells. PMID:16425294

  5. The basic helix-loop-helix differentiation factor Nex1/MATH-2 functions as a key activator of the GAP-43 gene.

    PubMed

    Uittenbogaard, Martine; Martinka, Debra L; Chiaramello, Anne

    2003-02-01

    Nex1/MATH-2 is a neurogenic basic Helix-Loop-Helix (bHLH) transcription factor that belongs to the NeuroD subfamily. Its expression parallels that of the GAP-43 gene and peaks during brain development, when neurite outgrowth and synaptogenesis are highly active. We previously observed a direct correlation between the levels of expression of Nex1 and GAP-43 proteins, which resulted in extensive neurite outgrowth and neuronal differentiation of PC12 cells in the absence of nerve growth factor. Since the GAP-43 gene is a target for bHLH regulation, we investigated whether Nex1 could regulate the activity of the GAP-43 promoter. We found that among the members of the NeuroD subfamily, Nex1 promoted maximal activity of the GAP-43 promoter. The Nex1-mediated activity is restricted to the conserved E1-E2 cluster located near the major transcription start sites. By electrophoretic mobility shift assay and site-directed mutagenesis, we showed that Nex1 binds as homodimers and that the E1 E-box is a high affinity binding site. We further found that Nex1 released the ME1 E-protein-mediated repression in a concentration dependent manner. Thus, the E1-E2 cluster has a dual function: it can mediate activation or repression depending on the interacting bHLH proteins. Finally, a series of N-terminal and C-terminal deletions revealed that Nex1 transcriptional activity is linked to two distinct transactivation domains, TAD1 and TAD2, with TAD1 being unique to Nex1. Together, our results suggest that Nex1 may engage in selective interactions with components of the core transcriptional machinery whose assembly is dictated by the architecture of the GAP-43 promoter and cellular environment. PMID:12562512

  6. The basic helix-loop-helix differentiation factor Nex1/MATH-2 functions as a key activator of the GAP-43 gene

    PubMed Central

    Uittenbogaard, Martine; Martinka, Debra L.; Chiaramello, Anne

    2006-01-01

    Nex1/MATH-2 is a neurogenic basic Helix-Loop-Helix (bHLH) transcription factor that belongs to the NeuroD subfamily. Its expression parallels that of the GAP-43 gene and peaks during brain development, when neurite outgrowth and synaptogenesis are highly active. We previously observed a direct correlation between the levels of expression of Nex1 and GAP-43 proteins, which resulted in extensive neurite outgrowth and neuronal differentiation of PC12 cells in the absence of nerve growth factor. Since the GAP-43 gene is a target for bHLH regulation, we investigated whether Nex1 could regulate the activity of the GAP-43 promoter. We found that among the members of the NeuroD subfamily, Nex1 promoted maximal activity of the GAP-43 promoter. The Nex1-mediated activity is restricted to the conserved E1–E2 cluster located near the major transcription start sites. By electrophoretic mobility shift assay and site-directed mutagenesis, we showed that Nex1 binds as homodimers and that the E1 E-box is a high affinity binding site. We further found that Nex1 released the ME1 E-protein-mediated repression in a concentration dependent manner. Thus, the E1–E2 cluster has a dual function: it can mediate activation or repression depending on the interacting bHLH proteins. Finally, a series of N-terminal and C-terminal deletions revealed that Nex1 transcriptional activity is linked to two distinct transactivation domains, TAD1 and TAD2, with TAD1 being unique to Nex1. Together, our results suggest that Nex1 may engage in selective interactions with components of the core transcriptional machinery whose assembly is dictated by the architecture of the GAP-43 promoter and cellular environment. PMID:12562512

  7. TCFL4: a gene at 17q21.1 encoding a putative basic helix-loop-helix leucine-zipper transcription factor.

    PubMed

    Bjerknes, M; Cheng, H

    1996-11-28

    TCFL4 (transcription factor like 4) is the HGMW-approved symbol for the gene of a widely expressed putative basic helix-loop-helix leucine-zipper (bHLH-zip) transcription factor which is located 3' to HSD17B1 (17-beta-hydroxysteroid dehydrogenase gene) at 17q21.1, centromeric to the BRCA1 (a gene implicated in familial breast cancer) locus. We report the human gene structure and the murine cDNA sequence of two variants, about 1.5 and 2.2 kb in size. The deduced protein is highly conserved between mouse and man. PMID:8973301

  8. Iron-Binding E3 Ligase Mediates Iron Response in Plants by Targeting Basic Helix-Loop-Helix Transcription Factors1[OPEN

    PubMed Central

    Selote, Devarshi; Samira, Rozalynne; Matthiadis, Anna; Gillikin, Jeffrey W.; Long, Terri A.

    2015-01-01

    Iron uptake and metabolism are tightly regulated in both plants and animals. In Arabidopsis (Arabidopsis thaliana), BRUTUS (BTS), which contains three hemerythrin (HHE) domains and a Really Interesting New Gene (RING) domain, interacts with basic helix-loop-helix transcription factors that are capable of forming heterodimers with POPEYE (PYE), a positive regulator of the iron deficiency response. BTS has been shown to have E3 ligase capacity and to play a role in root growth, rhizosphere acidification, and iron reductase activity in response to iron deprivation. To further characterize the function of this protein, we examined the expression pattern of recombinant ProBTS::β-GLUCURONIDASE and found that it is expressed in developing embryos and other reproductive tissues, corresponding with its apparent role in reproductive growth and development. Our findings also indicate that the interactions between BTS and PYE-like (PYEL) basic helix-loop-helix transcription factors occur within the nucleus and are dependent on the presence of the RING domain. We provide evidence that BTS facilitates 26S proteasome-mediated degradation of PYEL proteins in the absence of iron. We also determined that, upon binding iron at the HHE domains, BTS is destabilized and that this destabilization relies on specific residues within the HHE domains. This study reveals an important and unique mechanism for plant iron homeostasis whereby an E3 ubiquitin ligase may posttranslationally control components of the transcriptional regulatory network involved in the iron deficiency response. PMID:25452667

  9. The Drosophila dysfusion basic helix-loop-helix (bHLH)-PAS gene controls tracheal fusion and levels of the trachealess bHLH-PAS protein.

    PubMed

    Jiang, Lan; Crews, Stephen T

    2003-08-01

    The development of the mature insect trachea requires a complex series of cellular events, including tracheal cell specification, cell migration, tubule branching, and tubule fusion. Here we describe the identification of the Drosophila melanogaster dysfusion gene, which encodes a novel basic helix-loop-helix (bHLH)-PAS protein conserved between Caenorhabditis elegans, insects, and humans, and controls tracheal fusion events. The Dysfusion protein functions as a heterodimer with the Tango bHLH-PAS protein in vivo to form a putative DNA-binding complex. The dysfusion gene is expressed in a variety of embryonic cell types, including tracheal-fusion, leading-edge, foregut atrium cells, nervous system, hindgut, and anal pad cells. RNAi experiments indicate that dysfusion is required for dorsal branch, lateral trunk, and ganglionic branch fusion but not for fusion of the dorsal trunk. The escargot gene, which is also expressed in fusion cells and is required for tracheal fusion, precedes dysfusion expression. Analysis of escargot mutants indicates a complex pattern of dysfusion regulation, such that dysfusion expression is dependent on escargot in the dorsal and ganglionic branches but not the dorsal trunk. Early in tracheal development, the Trachealess bHLH-PAS protein is present at uniformly high levels in all tracheal cells, but since the levels of Dysfusion rise in wild-type fusion cells, the levels of Trachealess in fusion cells decline. The downregulation of Trachealess is dependent on dysfusion function. These results suggest the possibility that competitive interactions between basic helix-loop-helix-PAS proteins (Dysfusion, Trachealess, and possibly Similar) may be important for the proper development of the trachea. PMID:12897136

  10. Dynamic Antagonism between Phytochromes and PIF Family Basic Helix-Loop-Helix Factors Induces Selective Reciprocal Responses to Light and Shade in a Rapidly Responsive Transcriptional Network in Arabidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants respond to shade-modulated light signals via phytochrome (phy)-induced adaptive changes, termed shade avoidance. To examine the roles of Phytochrome-Interacting basic helix-loop-helix Factors, PIF1, 3, 4, and 5, in relaying such signals to the transcriptional network, we compared the shade-re...

  11. Mutations of TCF12, encoding a basic-helix-loop-helix partner of TWIST1, are a frequent cause of coronal craniosynostosis

    PubMed Central

    Sharma, Vikram P; Fenwick, Aimée L; Brockop, Mia S; McGowan, Simon J; Goos, Jacqueline A C; Hoogeboom, A Jeannette M; Brady, Angela F; Jeelani, N u Owase; Lynch, Sally Ann; Mulliken, John B; Murray, Dylan J; Phipps, Julie M; Sweeney, Elizabeth; Tomkins, Susan E; Wilson, Louise C; Bennett, Sophia; Cornall, Richard J; Broxholme, John; Kanapin, Alexander; Johnson, David; Wall, Steven A; van der Spek, Peter J; Mathijssen, Irene M J; Maxson, Robert E; Twigg, Stephen R F; Wilkie, Andrew O M

    2013-01-01

    Craniosynostosis, the premature fusion of the cranial sutures, is a heterogeneous disorder with a prevalence of ~1 in 2,200 (refs. 1,2). A specific genetic etiology can be identified in ~21% of cases3, including mutations of TWIST1, which encodes a class II basic helix-loop-helix (bHLH) transcription factor, and causes Saethre-Chotzen syndrome, typically associated with coronal synostosis4-6. Starting with an exome sequencing screen, we identified 38 heterozygous TCF12 mutations in 347 samples from unrelated individuals with craniosynostosis. The mutations predominantly occurred in patients with coronal synostosis and accounted for 32% and 10% of subjects with bilateral and unilateral pathology, respectively. TCF12 encodes one of three class I E-proteins that heterodimerize with class II bHLH proteins such as TWIST1. We show that TCF12 and TWIST1 act synergistically in a transactivation assay, and that mice doubly heterozygous for loss-of-function mutations in Tcf12 and Twist1 exhibit severe coronal synostosis. Hence, the dosage of TCF12/TWIST1 heterodimers is critical for coronal suture development. PMID:23354436

  12. Mutations in TCF12, encoding a basic helix-loop-helix partner of TWIST1, are a frequent cause of coronal craniosynostosis.

    PubMed

    Sharma, Vikram P; Fenwick, Aimée L; Brockop, Mia S; McGowan, Simon J; Goos, Jacqueline A C; Hoogeboom, A Jeannette M; Brady, Angela F; Jeelani, Nu Owase; Lynch, Sally Ann; Mulliken, John B; Murray, Dylan J; Phipps, Julie M; Sweeney, Elizabeth; Tomkins, Susan E; Wilson, Louise C; Bennett, Sophia; Cornall, Richard J; Broxholme, John; Kanapin, Alexander; Johnson, David; Wall, Steven A; van der Spek, Peter J; Mathijssen, Irene M J; Maxson, Robert E; Twigg, Stephen R F; Wilkie, Andrew O M

    2013-03-01

    Craniosynostosis, the premature fusion of the cranial sutures, is a heterogeneous disorder with a prevalence of ∼1 in 2,200 (refs. 1,2). A specific genetic etiology can be identified in ∼21% of cases, including mutations of TWIST1, which encodes a class II basic helix-loop-helix (bHLH) transcription factor, and causes Saethre-Chotzen syndrome, typically associated with coronal synostosis. Using exome sequencing, we identified 38 heterozygous TCF12 mutations in 347 samples from unrelated individuals with craniosynostosis. The mutations predominantly occurred in individuals with coronal synostosis and accounted for 32% and 10% of subjects with bilateral and unilateral pathology, respectively. TCF12 encodes one of three class I E proteins that heterodimerize with class II bHLH proteins such as TWIST1. We show that TCF12 and TWIST1 act synergistically in a transactivation assay and that mice doubly heterozygous for loss-of-function mutations in Tcf12 and Twist1 have severe coronal synostosis. Hence, the dosage of TCF12-TWIST1 heterodimers is critical for normal coronal suture development. PMID:23354436

  13. B-lymphocyte development is regulated by the combined dosage of three basic helix-loop-helix genes, E2A, E2-2, and HEB.

    PubMed Central

    Zhuang, Y; Cheng, P; Weintraub, H

    1996-01-01

    B-lymphocyte development requires the basic helix-loop-helix proteins encoded by the E2A gene. In this study, the control mechanism of E2A was further explored by disruption of the E2A-related genes, E2-2 and HEB. In contrast to E2A, E2-2 and HEB are not essential for the establishment of the B-cell lineage. However, both E2-2 and HEB are required for the generation of the normal numbers of pro-B cells in mouse embryos. Breeding tests among mice carrying different mutations revealed that E2-2 and HEB interact with E2A in many developmental processes including generation of B cells. Specifically, mice transheterozygous for any two mutations of these three genes produced fewer pro-B cells than the singly heterozygous littermates. This study indicates that B-cell development is dependent not only on an essential function provided by the E2A gene but also on a combined dosage set by E2A, E2-2, and HEB. PMID:8649400

  14. RETARDED GROWTH OF EMBRYO1, a New Basic Helix-Loop-Helix Protein, Expresses in Endosperm to Control Embryo Growth1[W

    PubMed Central

    Kondou, Youichi; Nakazawa, Miki; Kawashima, Mika; Ichikawa, Takanari; Yoshizumi, Takeshi; Suzuki, Kumiko; Ishikawa, Akie; Koshi, Tomoko; Matsui, Ryo; Muto, Shu; Matsui, Minami

    2008-01-01

    We have isolated two dominant mutants from screening approximately 50,000 RIKEN activation-tagging lines that have short inflorescence internodes. The activation T-DNAs were inserted near a putative basic helix-loop-helix (bHLH) gene and expression of this gene was increased in the mutant lines. Overexpression of this bHLH gene produced the original mutant phenotype, indicating it was responsible for the mutants. Specific expression was observed during seed development. The loss-of-function mutation of the RETARDED GROWTH OF EMBRYO1 (RGE1) gene caused small and shriveled seeds. The embryo of the loss-of-function mutant showed retarded growth after the heart stage although abnormal morphogenesis and pattern formation of the embryo and endosperm was not observed. We named this bHLH gene RGE1. RGE1 expression was determined in endosperm cells using the β-glucuronidase reporter gene and reverse transcription-polymerase chain reaction. Microarray and real-time reverse transcription-polymerase chain reaction analysis showed specific down-regulation of putative GDSL motif lipase genes in the rge1-1 mutant, indicating possible involvement of these genes in seed morphology. These data suggest that RGE1 expression in the endosperm at the heart stage of embryo development plays an important role in controlling embryo growth. PMID:18567831

  15. The Rice Basic Helix-Loop-Helix Transcription Factor TDR INTERACTING PROTEIN2 Is a Central Switch in Early Anther Development[C][W

    PubMed Central

    Fu, Zhenzhen; Yu, Jing; Cheng, Xiaowei; Zong, Xu; Xu, Jie; Chen, Mingjiao; Li, Zongyun; Zhang, Dabing; Liang, Wanqi

    2014-01-01

    In male reproductive development in plants, meristemoid precursor cells possessing transient, stem cell–like features undergo cell divisions and differentiation to produce the anther, the male reproductive organ. The anther contains centrally positioned microsporocytes surrounded by four distinct layers of wall: the epidermis, endothecium, middle layer, and tapetum. Here, we report that the rice (Oryza sativa) basic helix-loop-helix (bHLH) protein TDR INTERACTING PROTEIN2 (TIP2) functions as a crucial switch in the meristemoid transition and differentiation during early anther development. The tip2 mutants display undifferentiated inner three anther wall layers and abort tapetal programmed cell death, causing complete male sterility. TIP2 has two paralogs in rice, TDR and EAT1, which are key regulators of tapetal programmed cell death. We revealed that TIP2 acts upstream of TDR and EAT1 and directly regulates the expression of TDR and EAT1. In addition, TIP2 can interact with TDR, indicating a role of TIP2 in later anther development. Our findings suggest that the bHLH proteins TIP2, TDR, and EAT1 play a central role in regulating differentiation, morphogenesis, and degradation of anther somatic cell layers, highlighting the role of paralogous bHLH proteins in regulating distinct steps of plant cell–type determination. PMID:24755456

  16. The Basic Helix-Loop-Helix Transcription Factor E47 Reprograms Human Pancreatic Cancer Cells to a Quiescent Acinar State With Reduced Tumorigenic Potential

    PubMed Central

    Kim, SangWun; Lahmy, Reyhaneh; Riha, Chelsea; Yang, Challeng; Jakubison, Brad L.; van Niekerk, Jaco; Staub, Claudio; Wu, Yifan; Gates, Keith; Dong, Duc Si; Konieczny, Stephen F.; Itkin-Ansari, Pamela

    2015-01-01

    Objectives Pancreatic ductal adenocarcinoma (PDA) initiates from quiescent acinar cells that attain a Kras mutation, lose signaling from basic helix-loop-helix (bHLH) transcription factors, undergo acinar-ductal metaplasia, and rapidly acquire increased growth potential. We queried whether PDA cells can be reprogrammed to revert to their original quiescent acinar cell state by shifting key transcription programs. Methods Human PDA cell lines were engineered to express an inducible form of the bHLH protein E47. Gene expression, growth, and functional studies were investigated using microarray, quantitative polymerase chain reaction, immunoblots, immunohistochemistry, small interfering RNA, chromatin immunoprecipitation analyses, and cell transplantation into mice. Results In human PDA cells, E47 activity triggers stable G0/G1 arrest, which requires the cyclin-dependent kinase inhibitor p21 and the stress response protein TP53INP1. Concurrently, E47 induces high level expression of acinar digestive enzymes and feed forward activation of the acinar maturation network regulated by the bHLH factor MIST1. Moreover, induction of E47 in human PDA cells in vitro is sufficient to inhibit tumorigenesis. Conclusions Human PDA cells retain a high degree of plasticity, which can be exploited to induce a quiescent acinar cell state with reduced tumorigenic potential. Moreover, bHLH activity is a critical node coordinately regulating human PDA cell growth versus cell fate. PMID:25894862

  17. Basic helix-loop-helix transcription factor from wild rice (OrbHLH2) improves tolerance to salt- and osmotic stress in Arabidopsis.

    PubMed

    Zhou, Jing; Li, Fei; Wang, Jin-Lan; Ma, Yun; Chong, Kang; Xu, Yun-yuan

    2009-08-15

    Salt stress adversely affects plant growth and development. Some plants reduce the damage of high-salt stress by expressing a series of salt-responsive genes. Studies of the molecular mechanism of the salt-stress response have focused on the characterization of components involved in signal perception and transduction. In the present work, we cloned and characterized a basic helix-loop-helix (bHLH) encoding gene, OrbHLH2, from wild rice (Oryza rufipogon), which encodes a homologue protein of ICE1 in Arabidopsis. OrbHLH2 protein localized in the nucleus. Overexpression of OrbHLH2 in Arabidopsis conferred increased tolerance to salt and osmotic stress, and the stress-responsive genes DREB1A/CBF3, RD29A, COR15A and KIN1 were upregulated in transgenic plants. Abscisic acid (ABA) treatment showed a similar effect on the seed germination or transcriptional expression of stress-responsive genes in both wild type and OrbHLH2-overexpressed plants, which implies that OrbHLH2 does not depend on ABA in responding to salt stress. OrbHLH2 may function as a transcription factor and positively regulate salt-stress signals independent of ABA in Arabidopsis, which provides some useful data for improving salt tolerance in crops. PMID:19324458

  18. Endosperm breakdown in Arabidopsis requires heterodimers of the basic helix-loop-helix proteins ZHOUPI and INDUCER OF CBP EXPRESSION 1.

    PubMed

    Denay, Grégoire; Creff, Audrey; Moussu, Steven; Wagnon, Pauline; Thévenin, Johanne; Gérentes, Marie-France; Chambrier, Pierre; Dubreucq, Bertrand; Ingram, Gwyneth

    2014-03-01

    In Arabidopsis seeds, embryo growth is coordinated with endosperm breakdown. Mutants in the endosperm-specific gene ZHOUPI (ZOU), which encodes a unique basic helix-loop-helix (bHLH) transcription factor, have an abnormal endosperm that persists throughout seed development, significantly impeding embryo growth. Here we show that loss of function of the bHLH-encoding gene INDUCER OF CBP EXPRESSION 1 (ICE1) causes an identical endosperm persistence phenotype. We show that ZOU and ICE1 are co-expressed in the endosperm and interact in yeast via their bHLH domains. We show both genetically and in a heterologous plant system that, despite the fact that both ZOU and ICE1 can form homodimers in yeast, their role in endosperm breakdown requires their heterodimerization. Consistent with this conclusion, we confirm that ZOU and ICE1 regulate the expression of common target genes in the developing endosperm. Finally, we show that heterodimerization of ZOU and ICE1 is likely to be necessary for their binding to specific targets, rather than for their nuclear localization in the endosperm. By comparing our results with paradigms of bHLH function and evolution in animal systems we propose that the ZOU/ICE1 complex might have ancient origins, acquiring novel megagametophyte-specific functions in heterosporous land plants that were conserved in the angiosperm endosperm. PMID:24553285

  19. Identification and functional analysis of porcine basic helix-loop-helix transcriptional factor 3 (TCF3) and its alternative splicing isoforms.

    PubMed

    Yang, Fan; Wang, Ning; Liu, Yajun; Wang, Huayan

    2016-04-01

    The transcription factor 3 (TCF3) is a basic helix-loop-helix transcription factor and is essential for lymphocyte development and epithelial-mesenchymal transition. The splicing isoform, genomic organization and physiological roles of TCF3 have not been elucidated well in pig. Based on RNA-seq database, four alternative splicing isoforms were identified. Splicing isoforms TCF3(E12), TCF3(E47), and TCF3A expressed globally in porcine tissues, but TCF3B mainly expressed in spleen and endoderm derived tissues, such as pancreas and lung. The functional analysis showed that TCF3(E12), TCF3(E47), and TCF3B were translocated exclusively into nuclei, yet TCF3A was distributed in cytoplasm. The investigation of clinical specimens showed that TCF3 expression was significantly reduced in spleen tissues that were infected by classical swine fever virus (CSFV). This study is for the first time to report two novel splicing isoforms TCF3A and TCF3B, which may play an important role in lymphocyte maturation and have the correlation with CSFV evasion. PMID:27033898

  20. Arabidopsis Basic Helix-Loop-Helix Transcription Factors MYC2, MYC3, and MYC4 Regulate Glucosinolate Biosynthesis, Insect Performance, and Feeding Behavior[W][OPEN

    PubMed Central

    Schweizer, Fabian; Fernández-Calvo, Patricia; Zander, Mark; Diez-Diaz, Monica; Fonseca, Sandra; Glauser, Gaétan; Lewsey, Mathew G.; Ecker, Joseph R.; Solano, Roberto; Reymond, Philippe

    2013-01-01

    Arabidopsis thaliana plants fend off insect attack by constitutive and inducible production of toxic metabolites, such as glucosinolates (GSs). A triple mutant lacking MYC2, MYC3, and MYC4, three basic helix-loop-helix transcription factors that are known to additively control jasmonate-related defense responses, was shown to have a highly reduced expression of GS biosynthesis genes. The myc2 myc3 myc4 (myc234) triple mutant was almost completely devoid of GS and was extremely susceptible to the generalist herbivore Spodoptera littoralis. On the contrary, the specialist Pieris brassicae was unaffected by the presence of GS and preferred to feed on wild-type plants. In addition, lack of GS in myc234 drastically modified S. littoralis feeding behavior. Surprisingly, the expression of MYB factors known to regulate GS biosynthesis genes was not altered in myc234, suggesting that MYC2/MYC3/MYC4 are necessary for direct transcriptional activation of GS biosynthesis genes. To support this, chromatin immunoprecipitation analysis showed that MYC2 binds directly to the promoter of several GS biosynthesis genes in vivo. Furthermore, yeast two-hybrid and pull-down experiments indicated that MYC2/MYC3/MYC4 interact directly with GS-related MYBs. This specific MYC–MYB interaction plays a crucial role in the regulation of defense secondary metabolite production and underlines the importance of GS in shaping plant interactions with adapted and nonadapted herbivores. PMID:23943862

  1. Effects of postweaning administration of conjugated linoleic acid on development of obesity in nescient basic helix-loop-helix 2 knockout mice.

    PubMed

    Kim, Yoo; Kim, Daeyoung; Good, Deborah J; Park, Yeonhwa

    2015-06-01

    Conjugated linoleic acid (CLA) has been reported to prevent body weight gain and fat accumulation in part by improving physical activity in mice. However, the effects of postweaning administration of CLA on the development of obesity later in life have not yet been demonstrated. The current study investigated the role of postweaning CLA treatment on skeletal muscle energy metabolism in genetically induced inactive adult-onset obese model, nescient basic helix-loop-helix 2 knockout (N2KO) mice. Four-week-old male N2KO and wild type mice were fed either control or a CLA-containing diet (0.5%) for 4 weeks, and then CLA was withdrawn and control diet provided to all mice for the following 8 weeks. Postweaning CLA supplementation in wild type animals, but not N2KO mice, may activate AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-δ (PPARδ) as well as promote desensitization of phosphatase and tensin homologue (PTEN) and sensitization of protein kinase B (AKT) at threonine 308 in gastrocnemius skeletal muscle, improving voluntary activity and glucose homeostasis. We suggest that postweaning administration of CLA may in part stimulate the underlying molecular targets involved in muscle energy metabolism to reduce weight gain in normal animals, but not in the genetically induced inactive adult-onset animal model. PMID:25976059

  2. PIL5, a Phytochrome-Interacting Basic Helix-Loop-Helix Protein, Is a Key Negative Regulator of Seed Germination in Arabidopsis thalianaW⃞

    PubMed Central

    Oh, Eunkyoo; Kim, Jonghyun; Park, Eunae; Kim, Jeong-Il; Kang, Changwon; Choi, Giltsu

    2004-01-01

    The first decision made by an angiosperm seed, whether to germinate or not, is based on integration of various environmental signals such as water and light. The phytochromes (Phys) act as red and far-red light (Pfr) photoreceptors to mediate light signaling through yet uncharacterized pathways. We report here that the PIF3-like 5 (PIL5) protein, a basic helix-loop-helix transcription factor, is a key negative regulator of phytochrome-mediated seed germination. PIL5 preferentially interacts with the Pfr forms of Phytochrome A (PhyA) and Phytochrome B (PhyB). Analyses of a pil5 mutant in conjunction with phyA and phyB mutants, a pif3 pil5 double mutant, and PIL5 overexpression lines indicate that PIL5 is a negative factor in Phy-mediated promotion of seed germination, inhibition of hypocotyl negative gravitropism, and inhibition of hypocotyl elongation. Our data identify PIL5 as the first Phy-interacting protein that regulates seed germination. PMID:15486102

  3. Identification of a novel basic helix-loop-helix-PAS factor, NXF, reveals a Sim2 competitive, positive regulatory role in dendritic-cytoskeleton modulator drebrin gene expression.

    PubMed

    Ooe, Norihisa; Saito, Koichi; Mikami, Nobuyoshi; Nakatuka, Iwao; Kaneko, Hideo

    2004-01-01

    Sim2, a basic helix-loop-helix (bHLH)-PAS transcriptional repressor, is thought to be involved in some symptoms of Down's syndrome. In the course of searching for hypothetical Sim2 relatives, we isolated another bHLH-PAS factor, NXF. NXF was a novel gene and was selectively expressed in neuronal tissues. While no striking homolog of NXF was found in vertebrates, a Caenorhabditis elegans putative transcription factor, C15C8.2, showed similarity in the bHLH-PAS domain. NXF had an activation domain as a transcription activator, and Arnt-type bHLH-PAS subfamily members were identified as the heterodimer partners of NXF. The NXF/Arnt heterodimer was capable of binding and activating a subset of Sim2/Arnt target DNA variants, and Sim2 could compete with the NXF activity on the elements. We showed that Drebrin had several such NXF/Arnt binding elements on the promoter, which could be direct or indirect cross talking points between NXF (activation) and Sim2 (repression) action. Drebrin has been reported to be engaged in dendritic-cytoskeleton modulation at synapses, and such a novel NXF signaling system on neural gene promoter may be a molecular target of the adverse effects of Sim2 in the mental retardation of Down's syndrome. PMID:14701734

  4. MicroRNA-212 Post-Transcriptionally Regulates Oocyte-Specific Basic-Helix-Loop-Helix Transcription Factor, Factor in the Germline Alpha (FIGLA), during Bovine Early Embryogenesis

    PubMed Central

    Tripurani, Swamy K.; Wee, Gabbine; Lee, Kyung-Bon; Smith, George W.; Wang, Lei; JianboYao

    2013-01-01

    Factor in the germline alpha (FIGLA) is an oocyte-specific basic helix-loop-helix transcription factor essential for primordial follicle formation and expression of many genes required for folliculogenesis, fertilization and early embryonic survival. Here we report the characterization of bovine FIGLA gene and its regulation during early embryogenesis. Bovine FIGLA mRNA expression is restricted to gonads and is detected in fetal ovaries harvested as early as 90 days of gestation. FIGLA mRNA and protein are abundant in germinal vesicle and metaphase II stage oocytes, as well as in embryos from pronuclear to eight-cell stage but barely detectable at morula and blastocyst stages, suggesting that FIGLA might be a maternal effect gene. Recent studies in zebrafish and mice have highlighted the importance of non-coding small RNAs (microRNAs) as key regulatory molecules targeting maternal mRNAs for degradation during embryonic development. We hypothesized that FIGLA, as a maternal transcript, is regulated by microRNAs during early embryogenesis. Computational predictions identified a potential microRNA recognition element (MRE) for miR-212 in the 3’ UTR of the bovine FIGLA mRNA. Bovine miR-212 is expressed in oocytes and tends to increase in four-cell and eight-cell stage embryos followed by a decline at morula and blastocyst stages. Transient transfection and reporter assays revealed that miR-212 represses the expression of FIGLA in a MRE dependent manner. In addition, ectopic expression of miR-212 mimic in bovine early embryos dramatically reduced the expression of FIGLA protein. Collectively, our results demonstrate that FIGLA is temporally regulated during bovine early embryogenesis and miR-212 is an important negative regulator of FIGLA during the maternal to zygotic transition in bovine embryos. PMID:24086699

  5. A basic-region helix-loop-helix protein-encoding gene (devR) involved in the development of Aspergillus nidulans.

    PubMed

    Tüncher, André; Reinke, Hans; Martic, Goran; Caruso, Maria Louise; Brakhage, Axel A

    2004-04-01

    Basic-region helix-loop-helix (bHLH) proteins form an interesting class of eukaryotic transcription factors often involved in developmental processes. Here, a so far unknown bHLH protein-encoding gene of the filamentous ascomycete Aspergillus nidulans was isolated and designated devR for regulator of development. Deletion of devR revealed that the gene is non-essential for vegetative growth. However, the deletion mutant produced wrinkled colonies, a yellow pigment and did not form conidia on minimal agar plates. Conidiophore development was initiated normally, and colonies produced conidiophores with metulae and phialides. However, the phialides continued to grow filamentously and produced a second conidiophore with a vesicle at its end. The addition of KCl (0.6 M) to the medium suppressed the knock-out phenotype. The DeltadevR phenotype resembled that of a mutation in the tcsA gene encoding a histidine kinase domain and a response regulator domain. Here, we generated a tcsA deletion mutant. In a DeltatcsA strain, a DevR-Egfp protein fusion was detected in the cytoplasm, whereas in the wild type, the protein fusion was exclusively located in the nuclei, indicating that TcsA is required for nuclear localization of DevR. devR mRNA steady-state levels were similar in sporulating and vegetatively growing mycelia, and independent of a functional brlA gene. Moreover, under all conditions tested, self-crossing of the DeltadevR mutant strain was never observed. Taken together, devR encodes a bHLH regulatory protein that is part of the tcsA signal transduction network and required for development under standard growth conditions. PMID:15049823

  6. The basic helix-loop-helix transcription factor HEBAlt is expressed in pro-T cells and enhances the generation of T cell precursors.

    PubMed

    Wang, Duncheng; Claus, Carol L; Vaccarelli, Giovanna; Braunstein, Marsela; Schmitt, Thomas M; Zúñiga-Pflücker, Juan Carlos; Rothenberg, Ellen V; Anderson, Michele K

    2006-07-01

    The basic helix-loop-helix (bHLH) transcription factors HEB and E2A are critical mediators of gene regulation during lymphocyte development. We have cloned a new transcription factor, called HEBAlt, from a pro-T cell cDNA library. HEBAlt is generated by alternative transcriptional initiation and splicing from the HEB gene locus, which also encodes the previously characterized E box protein HEBCan. HEBAlt contains a unique N-terminal coding exon (the Alt domain) that replaces the first transactivation domain of HEBCan. Downstream of the Alt domain, HEBAlt is identical to HEBCan, including the DNA binding domain. HEBAlt is induced in early thymocyte precursors and down-regulated permanently at the double negative to double positive (DP) transition, whereas HEBCan mRNA expression peaks at the DP stage of thymocyte development. HEBAlt mRNA is up-regulated synergistically by a combination of HEBCan activity and Delta-Notch signaling. Retroviral transduction of HEBAlt or HEBCan into hemopoietic stem cells followed by OP9-DL1 coculture revealed that HEBAlt-transduced precursors generated more early T lineage precursors and more DP pre-T cells than control transduced cells. By contrast, HEBCan-transduced cells that maintained high level expression of the HEBCan transgene were inhibited in expansion and progression through T cell development. HEB(-/-) fetal liver precursors transduced with HEBAlt were rescued from delayed T cell specification, but HEBCan-transduced HEB(-/-) precursors were not. Therefore, HEBAlt and HEBCan are functionally distinct transcription factors, and HEBAlt is specifically required for the efficient generation of early T cell precursors. PMID:16785505

  7. The cold-induced basic helix-loop-helix transcription factor gene MdCIbHLH1 encodes an ICE-like protein in apple

    PubMed Central

    2012-01-01

    Background Plant growth is greatly affected by low temperatures, and the expression of a number of genes is induced by cold stress. Although many genes in the cold signaling pathway have been identified in Arabidopsis, little is known about the transcription factors involved in the cold stress response in apple. Results Here, we show that the apple bHLH (basic helix-loop-helix) gene MdCIbHLH1 (Cold-Induced bHLH1), which encodes an ICE-like protein, was noticeably induced in response to cold stress. The MdCIbHLH1 protein specifically bound to the MYC recognition sequences in the AtCBF3 promoter, and MdCIbHLH1 overexpression enhanced cold tolerance in transgenic Arabidopsis. In addition, the MdCIbHLH1 protein bound to the promoters of MdCBF2 and favorably contributed to cold tolerance in transgenic apple plants by upregulating the expression of MdCBF2 through the CBF (C-repeat-binding factor) pathway. Our findings indicate that MdCIbHLH1 functions in stress tolerance in different species. For example, ectopic MdCIbHLH1 expression conferred enhanced chilling tolerance in transgenic tobacco. Finally, we observed that cold induces the degradation of the MdCIbHLH1 protein in apple and that this degradation was potentially mediated by ubiquitination and sumoylation. Conclusions Based on these findings, MdCIbHLH1 encodes a transcription factor that is important for the cold tolerance response in apple. PMID:22336381

  8. Basic helix-loop-helix transcription factor BcbHLHpol functions as a positive regulator of pollen development in non-heading Chinese cabbage.

    PubMed

    Liu, Tongkun; Li, Ying; Zhang, Changwei; Duan, Weike; Huang, Feiyi; Hou, Xilin

    2014-12-01

    Cytoplasmic male sterility (CMS) is a common trait in higher plants, and several transcription factors regulate pollen development. Previously, we obtained a basic helix-loop-helix transcription factor, BcbHLHpol, via suppression subtractive hybridization in non-heading Chinese cabbage. However, the regulatory function of BcbHLHpol during anther and pollen development remains unclear. In this study, BcbHLHpol was cloned, and its tissue-specific expression profile was analyzed. The results of real-time polymerase chain reaction showed that BcbHLHpol was highly expressed in maintainer buds and that the transcripts of BcbHLHpol significantly decreased in the buds of pol CMS. A virus-induced gene silencing vector that targets BcbHLHpol was constructed and transformed into Brassica campestris plants to further explore the function of BcbHLHpol. Male sterility and short stature were observed in BcbHLHpol-silenced plants. The degradation of tapetal cells was inhibited in BcbHLHpol-silenced plants, and nutrients were insufficiently supplied to the microspore. These phenomena resulted in pollen abortion. This result indicates that BcbHLHpol functions as a positive regulator in pollen development. Yeast two-hybrid and bimolecular fluorescence complementation assays revealed that BcbHLHpol interacted with BcSKP1 in the nucleus. This finding suggests that BcbHLHpol and BcSKP1 are positive coordinating regulators of pollen development. Quantitative real-time PCR indicated that BcbHLHpol and BcSKP1 can be induced at low temperatures. Thus, we propose that BcbHLHpol is necessary for meiosis. This study provides insights into the regulatory functions of the BcbHLHpol network during anther development. PMID:25147023

  9. The poplar basic helix-loop-helix transcription factor BEE3 – Like gene affects biomass production by enhancing proliferation of xylem cells in poplar

    SciTech Connect

    Noh, Seol Ah Choi, Young-Im Cho, Jin-Seong Lee, Hyoshin

    2015-06-19

    Brassinosteroids (BRs) play important roles in many aspects of plant growth and development, including regulation of vascular cambium activities and cell elongation. BR-induced BEE3 (brassinosteroid enhanced expression 3) is required for a proper BR response. Here, we identified a poplar (Populus alba × Populus glandulosa) BEE3-like gene, PagBEE3L, encoding a putative basic helix-loop-helix (bHLH)-type transcription factor. Expression of PagBEE3L was induced by brassinolide (BL). Transcripts of PagBEE3L were mainly detected in stems, with the internode having a low level of transcription and the node having a relatively higher level. The function of the PagBEE3L gene was investigated through phenotypic analyses with PagBEE3L-overexpressing (ox) transgenic lines. This work particularly focused on a potential role of PagBEE3L in stem growth and development of polar. The PagBEE3L-ox poplar showed thicker and longer stems than wild-type plants. The xylem cells from the stems of PagBEE3L-ox plants revealed remarkably enhanced proliferation, resulting in an earlier thickening growth than wild-type plants. Therefore, this work suggests that xylem development of poplar is accelerated in PagBEE3L-ox plants and PagBEE3L plays a role in stem growth by increasing the proliferation of xylem cells to promote the initial thickening growth of poplar stems. - Highlights: • We identify the BEE3-like gene form hybrid poplar (Populus alba × Populus glandulosa). • We examine effects of overexpression of PagBEE3L on growth in poplar. • We found that 35S:BEE3L transgenic plants showed more rapid growth than wild-type plants. • BEE3L protein plays an important role in the development of plant stem.

  10. A basic helix-loop-helix transcription factor, PhFBH4, regulates flower senescence by modulating ethylene biosynthesis pathway in petunia

    PubMed Central

    Yin, Jing; Chang, Xiaoxiao; Kasuga, Takao; Bui, Mai; Reid, Michael S; Jiang, Cai-Zhong

    2015-01-01

    The basic helix-loop-helix (bHLH) transcription factors (TFs) play important roles in regulating multiple biological processes in plants. However, there are few reports about the function of bHLHs in flower senescence. In this study, a bHLH TF, PhFBH4, was found to be dramatically upregulated during flower senescence. Transcription of PhFBH4 is induced by plant hormones and abiotic stress treatments. Silencing of PhFBH4 using virus-induced gene silencing or an antisense approach extended flower longevity, while transgenic petunia flowers with an overexpression construct showed a reduction in flower lifespan. Abundance of transcripts of senescence-related genes (SAG12, SAG29) was significantly changed in petunia PhFBH4 transgenic flowers. Furthermore, silencing or overexpression of PhFBH4 reduced or increased, respectively, transcript abundances of important ethylene biosynthesis-related genes, ACS1 and ACO1, thereby influencing ethylene production. An electrophoretic mobility shift assay showed that the PhFBH4 protein physically interacted with the G-box cis-element in the promoter of ACS1, suggesting that ACS1 was a direct target of the PhFBH4 protein. In addition, ectopic expression of this gene altered plant development including plant height, internode length, and size of leaves and flowers, accompanied by alteration of transcript abundance of the gibberellin biosynthesis-related gene GA2OX3. Our results indicate that PhFBH4 plays an important role in regulating plant growth and development through modulating the ethylene biosynthesis pathway. PMID:26715989

  11. A Novel Molecular Recognition Motif Necessary for Targeting Photoactivated Phytochrome Signaling to Specific Basic Helix-Loop-Helix Transcription FactorsW⃞

    PubMed Central

    Khanna, Rajnish; Huq, Enamul; Kikis, Elise A.; Al-Sady, Bassem; Lanzatella, Christina; Quail, Peter H.

    2004-01-01

    The phytochrome (phy) family of sensory photoreceptors (phyA to phyE) in Arabidopsis thaliana control plant developmental transitions in response to informational light signals throughout the life cycle. The photoactivated conformer of the photoreceptor Pfr has been shown to translocate into the nucleus where it induces changes in gene expression by an unknown mechanism. Here, we have identified two basic helix-loop-helix (bHLH) transcription factors, designated PHYTOCHROME-INTERACTING FACTOR5 (PIF5) and PIF6, which interact specifically with the Pfr form of phyB. These two factors cluster tightly with PIF3 and two other phy-interacting bHLH proteins in a phylogenetic subfamily within the large Arabidopsis bHLH (AtbHLH) family. We have identified a novel sequence motif (designated the active phytochrome binding [APB] motif) that is conserved in these phy-interacting AtbHLHs but not in other noninteractors. Using the isolated domain and site-directed mutagenesis, we have shown that this motif is both necessary and sufficient for binding to phyB. Transgenic expression of the native APB-containing AtbHLH protein, PIF4, in a pif4 null mutant, rescued the photoresponse defect in this mutant, whereas mutated PIF4 constructs with site-directed substitutions in conserved APB residues did not. These data indicate that the APB motif is necessary for PIF4 function in light-regulated seedling development and suggest that conformer-specific binding of phyB to PIF4 via the APB motif is necessary for this function in vivo. Binding assays with the isolated APB domain detected interaction with phyB, but none of the other four Arabidopsis phys. Collectively, the data suggest that the APB domain provides a phyB-specific recognition module within the AtbHLH family, thereby conferring photoreceptor target specificity on a subset of these transcription factors and, thus, the potential for selective signal channeling to segments of the transcriptional network. PMID:15486100

  12. Basic Helix-Loop-Helix Transcription Factors JASMONATE-ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3 Are Negative Regulators of Jasmonate Responses in Arabidopsis1[W][OPEN

    PubMed Central

    Sasaki-Sekimoto, Yuko; Jikumaru, Yusuke; Obayashi, Takeshi; Saito, Hikaru; Masuda, Shinji; Kamiya, Yuji; Ohta, Hiroyuki; Shirasu, Ken

    2013-01-01

    Jasmonates regulate transcriptional reprogramming during growth, development, and defense responses. Jasmonoyl-isoleucine, an amino acid conjugate of jasmonic acid (JA), is perceived by the protein complex composed of the F-box protein CORONATINE INSENSITIVE1 (COI1) and JASMONATE ZIM DOMAIN (JAZ) proteins, leading to the ubiquitin-dependent degradation of JAZ proteins. This activates basic helix-loop-helix-type MYC transcription factors to regulate JA-responsive genes. Here, we show that the expression of genes encoding other basic helix-loop-helix transcription factors, JASMONATE ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3, is positively regulated in a COI1- and MYC2-dependent manner in Arabidopsis (Arabidopsis thaliana). However, contrary to myc2, the jam1jam2jam3 triple mutant exhibited shorter roots when treated with methyl jasmonate (MJ), indicating enhanced responsiveness to JA. Our genome-wide expression analyses revealed that key jasmonate metabolic genes as well as a set of genes encoding transcription factors that regulate the JA-responsive metabolic genes are negatively regulated by JAMs after MJ treatment. Consistently, loss of JAM genes resulted in higher accumulation of anthocyanin in MJ-treated plants as well as higher accumulation of JA and 12-hydroxyjasmonic acid in wounded plants. These results show that JAMs negatively regulate the JA responses in a manner that is mostly antagonistic to MYC2. PMID:23852442

  13. A Composite Element that Binds Basic Helix Loop Helix and Basic Leucine Zipper Transcription Factors Is Important for Gonadotropin-Releasing Hormone Regulation of the Follicle-Stimulating Hormone β Gene

    PubMed Central

    Ciccone, Nick A.; Lacza, Charlemagne T.; Hou, Melody Y.; Gregory, Susan J.; Kam, Kyung-Yoon; Xu, Shuyun; Kaiser, Ursula B.

    2008-01-01

    Although FSH plays an essential role in controlling gametogenesis, the biology of FSHβ transcription remains poorly understood, but is known to involve the complex interplay of multiple endocrine factors including GnRH. We have identified a GnRH-responsive element within the rat FSHβ promoter containing an E-box and partial cAMP response element site that are bound by the basic helix loop helix transcription factor family members, upstream stimulating factor (USF)-1/USF-2, and the basic leucine zipper member, cAMP response element-binding protein (CREB), respectively. Expression studies with CREB, USF-1/USF-2, and activating protein-1 demonstrated that the USF transcription factors increased basal transcription, an effect not observed if the cognate binding site was mutated. Conversely, expression of a dominant negative CREB mutant or CREB knockdown attenuated induction by GnRH, whereas dominant negative Fos or USF had no effect on the GnRH response. GnRH stimulation specifically induced an increase in phosphorylated CREB occupation of the FSHβ promoter, leading to the recruitment of CREB-binding protein to enhance gene transcription. In conclusion, a composite element bound by both USF and CREB serves to integrate signals for basal and GnRH-stimulated transcription of the rat FSHβ gene. PMID:18550775

  14. The Basic Helix-Loop-Helix Transcription Factor MYC2 Directly Represses PLETHORA Expression during Jasmonate-Mediated Modulation of the Root Stem Cell Niche in Arabidopsis[W][OA

    PubMed Central

    Chen, Qian; Sun, Jiaqiang; Zhai, Qingzhe; Zhou, Wenkun; Qi, Linlin; Xu, Li; Wang, Bao; Chen, Rong; Jiang, Hongling; Qi, Jing; Li, Xugang; Palme, Klaus; Li, Chuanyou

    2011-01-01

    The root stem cell niche, which in the Arabidopsis thaliana root meristem is an area of four mitotically inactive quiescent cells (QCs) and the surrounding mitotically active stem cells, is critical for root development and growth. We report here that during jasmonate-induced inhibition of primary root growth, jasmonate reduces root meristem activity and leads to irregular QC division and columella stem cell differentiation. Consistently, jasmonate reduces the expression levels of the AP2-domain transcription factors PLETHORA1 (PLT1) and PLT2, which form a developmentally instructive protein gradient and mediate auxin-induced regulation of stem cell niche maintenance. Not surprisingly, the effects of jasmonate on root stem cell niche maintenance and PLT expression require the functioning of MYC2/JASMONATE INSENSITIVE1, a basic helix-loop-helix transcription factor that involves versatile aspects of jasmonate-regulated gene expression. Gel shift and chromatin immunoprecipitation experiments reveal that MYC2 directly binds the promoters of PLT1 and PLT2 and represses their expression. We propose that MYC2-mediated repression of PLT expression integrates jasmonate action into the auxin pathway in regulating root meristem activity and stem cell niche maintenance. This study illustrates a molecular framework for jasmonate-induced inhibition of root growth through interaction with the growth regulator auxin. PMID:21954460

  15. The basic helix-loop-helix transcription factor Nex-1/Math-2 promotes neuronal survival of PC12 cells by modulating the dynamic expression of anti-apoptotic and cell cycle regulators

    PubMed Central

    Uittenbogaard, Martine; Chiaramello, Anne

    2006-01-01

    The basic helix-loop-helix transcription factor Nex1/Math-2 belongs to the NeuroD subfamily, which plays a critical role during neuronal differentiation and maintenance of the differentiated state. Previously, we demonstrated that Nex1 is a key regulatory component of the nerve growth factor (NGF) pathway. Further supporting this hypothesis, this study shows that Nex1 has survival-inducing properties similar to NGF, as Nex1-overexpressing PC12 cells survive in the absence of trophic factors. We dissected the molecular mechanism by which Nex1 confers neuroprotection upon serum removal and found that constitutive expression of Nex1 maintained the expression of specific G1 phase cyclin-dependent kinase inhibitors and concomitantly induced a dynamic expression profile of key anti-apoptotic regulators. This study provides the first evidence of the underlying mechanism by which a member of the NeuroD-subfamily promotes an active anti-apoptotic program essential to the survival of neurons. Our results suggest that the survival program may be viewed as an integral component of the intrinsic programming of the differ entiated state. PMID:15659228

  16. Basic Helix-Loop-Helix Transcription Factor Heterocomplex of Yas1p and Yas2p Regulates Cytochrome P450 Expression in Response to Alkanes in the Yeast Yarrowia lipolytica▿

    PubMed Central

    Endoh-Yamagami, Setsu; Hirakawa, Kiyoshi; Morioka, Daisuke; Fukuda, Ryouichi; Ohta, Akinori

    2007-01-01

    The expression of the ALK1 gene, which encodes cytochrome P450, catalyzing the first step of alkane oxidation in the alkane-assimilating yeast Yarrowia lipolytica, is highly regulated and can be induced by alkanes. Previously, we identified a cis-acting element (alkane-responsive element 1 [ARE1]) in the ALK1 promoter. We showed that a basic helix-loop-helix (bHLH) protein, Yas1p, binds to ARE1 in vivo and mediates alkane-dependent transcription induction. Yas1p, however, does not bind to ARE1 by itself in vitro, suggesting that Yas1p requires another bHLH protein partner for its DNA binding, as many bHLH transcription factors function by forming heterodimers. To identify such a binding partner of Yas1p, here we screened open reading frames encoding proteins with the bHLH motif from the Y. lipolytica genome database and identified the YAS2 gene. The deletion of the YAS2 gene abolished the alkane-responsive induction of ALK1 transcription and the growth of the yeast on alkanes. We revealed that Yas2p has transactivation activity. Furthermore, Yas1p and Yas2p formed a protein complex that was required for the binding of these proteins to ARE1. These findings allow us to postulate a model in which bHLH transcription factors Yas1p and Yas2p form a heterocomplex and mediate the transcription induction in response to alkanes. PMID:17322346

  17. Dynamic Antagonism between Phytochromes and PIF Family Basic Helix-Loop-Helix Factors Induces Selective Reciprocal Responses to Light and Shade in a Rapidly Responsive Transcriptional Network in Arabidopsis[C][W

    PubMed Central

    Leivar, Pablo; Tepperman, James M.; Cohn, Megan M.; Monte, Elena; Al-Sady, Bassem; Erickson, Erika; Quail, Peter H.

    2012-01-01

    Plants respond to shade-modulated light signals via phytochrome (phy)-induced adaptive changes, termed shade avoidance. To examine the roles of Phytochrome-Interacting basic helix-loop-helix Factors, PIF1, 3, 4, and 5, in relaying such signals to the transcriptional network, we compared the shade-responsive transcriptome profiles of wild-type and quadruple pif (pifq) mutants. We identify a subset of genes, enriched in transcription factor–encoding loci, that respond rapidly to shade, in a PIF-dependent manner, and contain promoter G-box motifs, known to bind PIFs. These genes are potential direct targets of phy-PIF signaling that regulate the primary downstream transcriptional circuitry. A second subset of PIF-dependent, early response genes, lacking G-box motifs, are enriched for auxin-responsive loci, and are thus potentially indirect targets of phy-PIF signaling, mediating the rapid cell expansion induced by shade. Comparing deetiolation- and shade-responsive transcriptomes identifies another subset of G-box–containing genes that reciprocally display rapid repression and induction in response to light and shade signals. These data define a core set of transcriptional and hormonal processes that appear to be dynamically poised to react rapidly to light-environment changes via perturbations in the mutually antagonistic actions of the phys and PIFs. Comparing the responsiveness of the pifq and triple pif mutants to light and shade confirms that the PIFs act with overlapping redundancy on seedling morphogenesis and transcriptional regulation but that each PIF contributes differentially to these responses. PMID:22517317

  18. Inhibitor of differentiation 4 (ID4) acts as an inhibitor of ID-1, -2 and -3 and promotes basic helix loop helix (bHLH) E47 DNA binding and transcriptional activity.

    PubMed

    Sharma, Pankaj; Chinaranagari, Swathi; Chaudhary, Jaideep

    2015-05-01

    The four known ID proteins (ID1-4, Inhibitor of Differentiation) share a homologous helix loop helix (HLH) domain and act as dominant negative regulators of basic-HLH transcription factors. ID proteins also interact with many non-bHLH proteins in complex networks. The expression of ID proteins is increasingly observed in many cancers. Whereas ID-1, ID-2 and ID-3, are generally considered as tumor promoters, ID4 on the contrary has emerged as a tumor suppressor. In this study we demonstrate that ID4 heterodimerizes with ID-1, -2 and -3 and promote bHLH DNA binding, essentially acting as an inhibitor of inhibitors of differentiation proteins. Interaction of ID4 was observed with ID1, ID2 and ID3 that was dependent on intact HLH domain of ID4. Interaction with bHLH protein E47 required almost 3 fold higher concentration of ID4 as compared to ID1. Furthermore, inhibition of E47 DNA binding by ID1 was restored by ID4 in an EMSA binding assay. ID4 and ID1 were also colocalized in prostate cancer cell line LNCaP. The alpha helix forming alanine stretch N-terminal, unique to HLH ID4 domain was required for optimum interaction. Ectopic expression of ID4 in DU145 prostate cancer line promoted E47 dependent expression of CDKNI p21. Thus counteracting the biological activities of ID-1, -2 and -3 by forming inactive heterodimers appears to be a novel mechanism of action of ID4. These results could have far reaching consequences in developing strategies to target ID proteins for cancer therapy and understanding biologically relevant ID-interactions. PMID:25778840

  19. Backbone dynamics of a symmetric calmodulin dimer in complex with the calmodulin-binding domain of the basic-helix-loop-helix transcription factor SEF2-1/E2-2: a highly dynamic complex.

    PubMed

    Larsson, Göran; Schleucher, Jürgen; Onions, Jacqueline; Hermann, Stefan; Grundström, Thomas; Wijmenga, Sybren S

    2005-08-01

    Calmodulin (CaM) interacts specifically as a dimer with some dimeric basic-Helix-Loop-Helix (bHLH) transcription factors via a novel high affinity binding mode. Here we report a study of the backbone dynamics by (15)N-spin relaxation on the CaM dimer in complex with a dimeric peptide that mimics the CaM binding region of the bHLH transcription factor SEF2-1. The relaxation data were measured at multiple magnetic fields, and analyzed in a model-free manner using in-house written software designed to detect nanosecond internal motion. Besides picosecond motions, all residues also experience internal motion with an effective correlation time of approximately 2.5 ns with squared order parameter (S(2)) of approximately 0.75. Hydrodynamic calculations suggest that this can be attributed to motions of the N- and C-terminal domains of the CaM dimer in the complex. Moreover, residues with significant exchange broadening are found. They are clustered in the CaM:SEF2-1mp binding interface, the CaM:CaM dimer interface, and in the flexible helix connecting the CaM N- and C-terminal domains, and have similar exchange times (approximately 50 micros), suggesting a cooperative mechanism probably caused by protein:protein interactions. The dynamic features presented here support the conclusion that the conformationally heterogeneous bHLH mimicking peptide trapped inside the CaM dimer exchanges between different binding sites on both nanosecond and microsecond timescales. Nature has thus found a way to specifically recognize a relatively ill-fitting target. This novel mode of target-specific binding, which neither belongs to lock-and-key nor induced-fit binding, is characterized by dimerization and continuous exchange between multiple flexible binding alternatives. PMID:15894636

  20. Concise review: Blood relatives: formation and regulation of hematopoietic stem cells by the basic helix-loop-helix transcription factors stem cell leukemia and lymphoblastic leukemia-derived sequence 1.

    PubMed

    Curtis, David J; Salmon, Jessica M; Pimanda, John E

    2012-06-01

    The basic helix-loop-helix (bHLH) proteins are a large family of transcription factors that regulate the formation and fate of tissue stem cells. In hematopoiesis, the two major bHLH factors are stem cell leukemia (SCL) and lymphoblastic leukemia-derived sequence 1 (LYL1), both identified more than 20 years ago in chromosomal translocations occurring in T-cell acute lymphoblastic leukemia. SCL was termed the master regulator of hematopoiesis following the observation that SCL knockout mice die from complete lack of blood formation. However, once established, SCL is no longer required for maintenance of hematopoiesis. Pull-down experiments together with add-back experiments in SCL-null embryonic stem cells and generation of mice carrying a germline DNA binding mutation of SCL demonstrates that most of SCL function is mediated through the formation of a large DNA binding multiprotein complex with both repressor and activator potential. Recent genome-wide binding studies in a hematopoietic stem progenitor cell line suggest that SCL and LYL1 preferentially bind target DNA sequences as components of a heptad of transcription factors. LYL1, a paralog of SCL has been the forgotten sibling until recent mouse studies demonstrated that LYL1 replaced the function of SCL in adult hematopoiesis. Why LYL1 can replace the function of SCL for the maintenance but not formation of hematopoiesis remains a fundamental question. This review will compare and contrast the roles of these two transcription factors in hematopoiesis focusing on recent functional and genome-wide binding studies. PMID:22593015

  1. Inhibitor of Differentiation 4 (ID4) Acts as an Inhibitor of ID-1, -2 and -3 and Promotes basic Helix Loop Helix (bHLH) E47 DNA Binding and Transcriptional Activity

    PubMed Central

    Sharma, Pankaj; Chinaranagari, Swathi; Chaudhary, Jaideep

    2015-01-01

    The four known ID proteins (ID1-4, Inhibitor of Differentiation) share a homologous helix loop helix (HLH) domain and act as dominant negative regulators of basic-HLH transcription factors. ID proteins also interact with many non-bHLH proteins in complex networks. The expression of ID proteins is increasingly observed in many cancers. Whereas ID-1, ID-2 and ID-3, are generally considered as tumor promoters, ID4 on the contrary has emerged as a tumor suppressor. In this study we demonstrate that ID4 heterodimerizes with ID-1, -2 and -3 and promote bHLH DNA binding, essentially acting as an inhibitor of inhibitors of differentiation proteins. Interaction of ID4 was observed with ID1, ID2 and ID3 that was dependent on intact HLH domain of ID4. Interaction with bHLH protein E47 required almost 3 fold higher concentration of ID4 as compared to ID1. Furthermore, inhibition of E47 DNA binding by ID1 was restored by ID4 in an EMSA binding assay. ID4 and ID1 were also colocalized in prostate cancer cell line LNCaP. The alpha helix forming alanine stretch N-terminal, unique to HLH ID4 domain was required for optimum interaction. Ectopic expression of ID4 in DU145 prostate cancer line promoted E47 dependent expression of CDKNI p21. Thus counteracting the biological activities of ID-1, -2 and -3 by forming inactive heterodimers appears to be a novel mechanism of action of ID4. These results could have far reaching consequences in developing strategies to target ID proteins for cancer therapy and understanding biologically relevant ID- interactions. PMID:25778840

  2. The neurogenic basic helix-loop-helix transcription factor NeuroD6 enhances mitochondrial biogenesis and bioenergetics to confer tolerance of neuronal PC12-NeuroD6 cells to the mitochondrial stressor rotenone

    SciTech Connect

    Baxter, Kristin Kathleen; Uittenbogaard, Martine; Chiaramello, Anne

    2012-10-15

    The fundamental question of how and which neuronal specific transcription factors tailor mitochondrial biogenesis and bioenergetics to the need of developing neuronal cells has remained largely unexplored. In this study, we report that the neurogenic basic helix-loop-helix transcription factor NeuroD6 possesses mitochondrial biogenic properties by amplifying the mitochondrial DNA content and TFAM expression levels, a key regulator for mitochondrial biogenesis. NeuroD6-mediated increase in mitochondrial biogenesis in the neuronal progenitor-like PC12-NEUROD6 cells is concomitant with enhanced mitochondrial bioenergetic functions, including increased expression levels of specific subunits of respiratory complexes of the electron transport chain, elevated mitochondrial membrane potential and ATP levels produced by oxidative phosphorylation. Thus, NeuroD6 augments the bioenergetic capacity of PC12-NEUROD6 cells to generate an energetic reserve, which confers tolerance to the mitochondrial stressor, rotenone. We found that NeuroD6 induces an adaptive bioenergetic response throughout rotenone treatment involving maintenance of the mitochondrial membrane potential and ATP levels in conjunction with preservation of the actin network. In conclusion, our results support the concept that NeuroD6 plays an integrative role in regulating and coordinating the onset of neuronal differentiation with acquisition of adequate mitochondrial mass and energetic capacity to ensure energy demanding events, such as cytoskeletal remodeling, plasmalemmal expansion, and growth cone formation. -- Highlights: Black-Right-Pointing-Pointer NeuroD6 induces mitochondrial biogenesis in neuroprogenitor-like cells. Black-Right-Pointing-Pointer NeuroD6 augments the bioenergetic reserve of the neuronal PC12-NeuroD6 cells. Black-Right-Pointing-Pointer NeuroD6 increases the mitochondrial membrane potential and ATP levels. Black-Right-Pointing-Pointer NeuroD6 confers tolerance to rotenone via an adaptive

  3. A Basic Helix-Loop-Helix Transcription Factor, PtrbHLH, of Poncirus trifoliata Confers Cold Tolerance and Modulates Peroxidase-Mediated Scavenging of Hydrogen Peroxide1[C][W

    PubMed Central

    Huang, Xiao-San; Wang, Wei; Zhang, Qian; Liu, Ji-Hong

    2013-01-01

    The basic helix-loop-helix (bHLH) transcription factors are involved in a variety of physiological processes. However, plant bHLHs functioning in cold tolerance and the underlying mechanisms remain poorly understood. Here, we report the identification and functional characterization of PtrbHLH isolated from trifoliate orange (Poncirus trifoliata). The transcript levels of PtrbHLH were up-regulated under various abiotic stresses, particularly cold. PtrbHLH was localized in the nucleus with transactivation activity. Overexpression of PtrbHLH in tobacco (Nicotiana tabacum) or lemon (Citrus limon) conferred enhanced tolerance to cold under chilling or freezing temperatures, whereas down-regulation of PtrbHLH in trifoliate orange by RNA interference (RNAi) resulted in elevated cold sensitivity. A range of stress-responsive genes was up-regulated or down-regulated in the transgenic lemon. Of special note, several peroxidase (POD) genes were induced after cold treatment. Compared with the wild type, POD activity was increased in the overexpression plants but decreased in the RNAi plants, which was inversely correlated with the hydrogen peroxide (H2O2) levels in the tested lines. Treatment of the transgenic tobacco plants with POD inhibitors elevated the H2O2 levels and greatly compromised their cold tolerance, while exogenous replenishment of POD enhanced cold tolerance of the RNAi line. In addition, transgenic tobacco and lemon plants were more tolerant to oxidative stresses. Yeast one-hybrid assay and transient expression analysis demonstrated that PtrbHLH could bind to the E-box elements in the promoter region of a POD gene. Taken together, these results demonstrate that PtrbHLH plays an important role in cold tolerance, at least in part, by positively regulating POD-mediated reactive oxygen species removal. PMID:23624854

  4. Differential activities of murine single minded 1 (SIM1) and SIM2 on a hypoxic response element. Cross-talk between basic helix-loop-helix/per-Arnt-Sim homology transcription factors.

    PubMed

    Woods, Susan L; Whitelaw, Murray L

    2002-03-22

    The basic helix-loop-helix/Per-Arnt-Sim homology (bHLH/PAS) protein family comprises a group of transcriptional regulators that often respond to a variety of developmental and environmental stimuli. Two murine members of this family, Single Minded 1 (SIM1) and Single Minded 2 (SIM2), are essential for postnatal survival but differ from other prototypical family members such as the dioxin receptor (DR) and hypoxia-inducible factors, in that they behave as transcriptional repressors in mammalian one-hybrid experiments and have yet to be ascribed a regulating signal. In cell lines engineered to stably express SIM1 and SIM2, we show that both are nuclear proteins that constitutively complex with the general bHLH/PAS partner factor, ARNT. We report that the murine SIM factors, in combination with ARNT, attenuate transcription from the hypoxia-inducible erythropoietin (EPO) enhancer during hypoxia. Such cross-talk between coexpressed bHLH/PAS factors can occur through competition for ARNT, which we find evident in SIM repression of DR-induced transcription from a xenobiotic response element reporter gene. However, SIM1/ARNT, but not SIM2/ARNT, can activate transcription from the EPO enhancer at normoxia, implying that the SIM proteins have the ability to bind hypoxia response elements and affect either activation or repression of transcription. This notion is supported by co-immunoprecipitation of EPO enhancer sequences with the SIM2 protein. SIM protein levels decrease with hypoxia treatment in our stable cell lines, although levels of the transcripts encoding SIM1 and SIM2 and the approximately 2-h half-lives of each protein are unchanged during hypoxia. Inhibition of protein synthesis, known to occur in cells during hypoxic stress in order to decrease ATP utilization, appears to account for the fall in SIM levels. Our data suggest the existence of a hypoxic switch mechanism in cells that coexpress hypoxia-inducible factor and SIM proteins, where up-regulation and

  5. E Proteins and ID Proteins: Helix-Loop-Helix Partners in Development and Disease.

    PubMed

    Wang, Lan-Hsin; Baker, Nicholas E

    2015-11-01

    The basic Helix-Loop-Helix (bHLH) proteins represent a well-known class of transcriptional regulators. Many bHLH proteins act as heterodimers with members of a class of ubiquitous partners, the E proteins. A widely expressed class of inhibitory heterodimer partners-the Inhibitor of DNA-binding (ID) proteins-also exists. Genetic and molecular analyses in humans and in knockout mice implicate E proteins and ID proteins in a wide variety of diseases, belying the notion that they are non-specific partner proteins. Here, we explore relationships of E proteins and ID proteins to a variety of disease processes and highlight gaps in knowledge of disease mechanisms. PMID:26555048

  6. Regulation of T cell receptor beta gene rearrangements and allelic exclusion by the helix-loop-helix protein, E47.

    PubMed

    Agata, Yasutoshi; Tamaki, Nobuyuki; Sakamoto, Shuji; Ikawa, Tomokatsu; Masuda, Kyoko; Kawamoto, Hiroshi; Murre, Cornelis

    2007-12-01

    Allelic exclusion of antigen-receptor genes is ensured primarily by monoallelic locus activation upon rearrangement and subsequently by feedback inhibition of continued rearrangement. Here, we demonstrated that the basic helix-loop-helix protein, E47, promoted T cell receptor beta (TCRbeta) gene rearrangement by directly binding to target gene segments to increase chromatin accessibility in a dosage-sensitive manner. Feedback signaling abrogated E47 binding, leading to a decline in accessibility. Conversely, enforced expression of E47 induced TCRbeta gene rearrangement by antagonizing feedback inhibition. Thus, the abundance of E47 is rate limiting in locus activation, and feedback signaling downregulates E47 activity to ensure allelic exclusion. PMID:18093539

  7. Suppression of mammary epithelial cell differentiation by the helix-loop-helix protein Id-1

    SciTech Connect

    Desprez, P.; Hara, E.; Bissell, M.J.

    1995-06-01

    Cell proliferation and differentiation are precisely coordinated during the development and maturation of the mammary gland, and this balance invariably is disrupted during carcinogenesis. Little is known about the cell-specific transcription factors that regulate these processes in the mammary gland. The mouse mammary epithelial cell line SCp2 grows well under standard culture conditions but arrests growth, forms alveolus-like structures, and expresses {beta}-casein, a differentiation marker, 4 to 5 days after exposure to basement membrane and lactogenic hormones (differentiation signals). The authors show that this differentiation entails a marked decline in the expression of Id-1, a helix-loop-helix (HLH) protein that inactivates basic HLH transcription factors in other cell types. SCp2 cells stably transfected with an Id-1 expression vector grew more rapidly than control cells under standard conditions, but in response to differentiation signals, they lost three-dimensional organization, invaded the basement membrane, and then resumed growth. SCp2 cells expressing an Id-1 antisense vector grew more slowly than controls; in response to differentiation signals, they remained stably growth arrested and fully differentiated, as did control cells. The authors suggest that Id-1 renders cells refractory to differentiation signals and receptive to growth signals by inactivating one or more basic HLH proteins that coordinate growth and differentiation in the mammary epithelium. 53 refs., 6 figs.

  8. Salvador-Warts-Hippo pathway in a developmental checkpoint monitoring Helix-Loop-Helix proteins

    PubMed Central

    Wang, Lan-Hsin; Baker, Nicholas E.

    2014-01-01

    The E-proteins and Id-proteins are, respectively, the positive and negative heterodimer partners for the basic-helix-loop-helix protein family, and as such contribute to a remarkably large number of cell fate decisions. E-proteins and Id-proteins also function to inhibit or promote cell proliferation and cancer. Using a genetic modifier screen in Drosophila, we show that the Id-protein Extramacrochaetae enables growth by suppressing activation of the Salvador-Warts-Hippo pathway of tumor suppressors, activation that requires transcriptional activation of the expanded gene by the E-protein Daughterless. Daughterless protein binds to an intronic enhancer in the expanded gene, both activating the SWH pathway independently of the transmembrane protein Crumbs, and bypassing the negative feedback regulation that targets the same expanded enhancer. Thus the Salvador-Warts-Hippo pathway has a cell-autonomous function to prevent inappropriate differentiation due to transcription factor imbalance, and monitors the intrinsic developmental status of progenitor cells, distinct from any responses to cell-cell interactions. PMID:25579975

  9. Helix-loop-helix transcription factors mediate activation and repression of the p75LNGFR gene.

    PubMed Central

    Chiaramello, A; Neuman, K; Palm, K; Metsis, M; Neuman, T

    1995-01-01

    Sequence analysis of rat and human low-affinity nerve growth factor receptor p75LNGFR gene promoter regions revealed a single E-box cis-acting element, located upstream of the major transcription start sites. Deletion analysis of the E-box sequence demonstrated that it significantly contributes to p75LNGFR promoter activity. This E box has a dual function; it mediates either activation or repression of the p75LNGFR promoter activity, depending on the interacting transcription factors. We showed that the two isoforms of the class A basic helix-loop-helix (bHLH) transcription factor ME1 (ME1a and ME1b), the murine homolog of the human HEB transcription factor, specifically repress p75LNGFR promoter activity. This repression can be released by coexpression of the HLH Id2 transcriptional regulator. In vitro analyses demonstrated that ME1a forms a stable complex with the p75LNGFR E box and likely competes with activating E-box-binding proteins. By using ME1a-overexpressing PC12 cells, we showed that the endogenous p75LNGFR gene is a target of ME1a repression. Together, these data demonstrate that the p75LNGFR E box and the interacting bHLH transcription factors are involved in the regulation of p75LNGFR gene expression. These results also show that class A bHLH transcription factors can repress and Id-like negative regulators can stimulate gene expression. PMID:7565756

  10. Enhancer of splitD, a dominant mutation of Drosophila, and its use in the study of functional domains of a helix-loop-helix protein.

    PubMed Central

    Tietze, K; Oellers, N; Knust, E

    1992-01-01

    Helix-loop-helix proteins play important roles in developmental processes, such as myogenesis, neurogenesis, and sex determination. The gene Enhancer of split [E(spl)] of Drosophila, a member of a gene complex that is involved in early neurogenesis, encodes a protein with a basic domain and a helix-loop-helix motif. We took advantage of a dominant mutation of this gene, E(spl)D, to define in vivo structural features of this protein for proper function. The mutation renders the otherwise recessive eye phenotype of spl dominant. By germ-line transformation of different in vitro mutagenized versions of the E(spl) gene, we could demonstrate that the basic domain of this helix-loop-helix protein is functional and necessary for expression of the dominant phenotype. These results are supported by in vitro DNA-binding assays, which showed that the basic domain is in fact necessary for DNA binding, despite the presence of a proline residue. Furthermore, we could show that the dominant enhancement of spl is caused by truncation of the E(SPL)D protein in combination with deletion of a putative regulatory element. Images PMID:1631102

  11. Suppression of Chondrogenesis by Id Helix-Loop-Helix Proteins in Murine Embryonic Orofacial Tissue

    PubMed Central

    Mukhopadhyay, Partha; Rezzoug, Francine; Webb, Cynthia L.; Pisano, M. Michele; Greene, Robert M.

    2009-01-01

    Inhibitors of differentiation (Id) proteins are helix-loop-helix (HLH) transcription factors lacking a DNA binding domain. Id proteins modulate cell proliferation, apoptosis, and differentiation in embryonic/fetal tissue. Perturbation of any of these processes in cells of the developing orofacial region results in orofacial anomalies. Chondrogenesis, a process integral to normal orofacial ontogenesis, is known to be modulated, in part, by Id proteins. In the present study, the mRNA and protein expression patterns of Id1, Id2, Id3 and Id4 were examined in developing murine orofacial tissue in vivo, as well as in murine embryonic maxillary mesenchymal cells in vitro. The functional role of Ids during chondrogenesis was also explored in vitro. Results reveal that cells derived from developing murine orofacial tissue: (1) express Id1, Id2, Id3 and Id4 mRNAs and proteins on each of gestational days 12-14, (2) express all four Id proteins in a developmentally regulated manner, (3) undergo chondrogenesis and express genes encoding various chondrogenic marker proteins (e.g. Runx2, Type X collagen, Sox9) when cultured under micromass conditions, and (4) can have their chondrogenic potential regulated via alteration of Id protein function through overexpression of a basic HLH factor. In summary, results from the current report reveal for the first time, the expression of all four Id proteins in cells derived from developing murine orofacial tissue, and demonstrate a functional role for the Ids in regulating the ability of these cells to undergo chondrogenesis. PMID:19349107

  12. CHUK, a conserved helix-loop-helix ubiquitous kinase, maps to human chromosome 10 and mouse chromosome 19

    SciTech Connect

    Mock, B.A.; McBride, O.W.; Kozak, C.A.

    1995-05-20

    Helix-loop-helix proteins contain stretches of DNA that encode two amphipathic {alpha}-helices joined by a loop structure and are involved in protein dimerization and transcriptional regulation essential to a variety of cellular processes. CHUK, a newly described conserved helix-loop-helix ubiquitous kinase, was mapped by somatic cell hybrid analyses to human Chr 10q24-q25. Chuk and a related sequence, Chuk-rs1, were mapped to mouse chromosomes 19 and 16, respectively, by a combination of somatic cell hybrid, recombinant inbred, and backcross analyses. 17 refs., 2 figs., 1 tab.

  13. Recognition and binding of a helix-loop-helix peptide to carbonic anhydrase occurs via partly folded intermediate structures.

    PubMed

    Lignell, Martin; Becker, Hans-Christian

    2010-02-01

    We have studied the association of a helix-loop-helix peptide scaffold carrying a benzenesulfonamide ligand to carbonic anhydrase using steady-state and time-resolved fluorescence spectroscopy. The helix-loop-helix peptide, developed for biosensing applications, is labeled with the fluorescent probe dansyl, which serves as a polarity-sensitive reporter of the binding event. Using maximum entropy analysis of the fluorescence lifetime of dansyl at 1:1 stoichiometry reveals three characteristic fluorescence lifetime groups, interpreted as differently interacting peptide/protein structures. We characterize these peptide/protein complexes as mostly bound but unfolded, bound and partly folded, and strongly bound and folded. Furthermore, analysis of the fluorescence anisotropy decay resulted in three different dansyl rotational correlation times, namely 0.18, 1.2, and 23 ns. Using the amplitudes of these times, we can correlate the lifetime groups with the corresponding fluorescence anisotropy component. The 23-ns rotational correlation time, which appears with the same amplitude as a 17-ns fluorescence lifetime, shows that the dansyl fluorophore follows the rotational diffusion of carbonic anhydrase when it is a part of the folded peptide/protein complex. A partly folded and partly hydrated interfacial structure is manifested in an 8-ns dansyl fluorescence lifetime and a 1.2-ns rotational correlation time. This structure, we believe, is similar to a molten-globule-like interfacial structure, which allows segmental movement and has a higher degree of solvent exposure of dansyl. Indirect excitation of dansyl on the helix-loop-helix peptide through Förster energy transfer from one or several tryptophans in the carbonic anhydrase shows that the helix-loop-helix scaffold binds to a tryptophan-rich domain of the carbonic anhydrase. We conclude that binding of the peptide to carbonic anhydrase involves a transition from a disordered to an ordered structure of the helix-loop-helix

  14. Macrocyclization and labeling of helix-loop-helix peptide with intramolecular bis-thioether linkage.

    PubMed

    Nishihara, Toshio; Kitada, Hidekazu; Fujiwara, Daisuke; Fujii, Ikuo

    2016-11-01

    Conformationally constrained peptides have been developed as an inhibitor for protein-protein interactions (PPIs), and we have de novo designed cyclized helix-loop-helix (cHLH) peptide with a disulfide bond consisting of 40 amino acids to generate molecular-targeting peptides. However, synthesis of long peptides has sometimes resulted in low yield according to the respective amino acid sequences. Here we developed a method for efficient synthesis and labeling for cHLH peptides. First, we synthesized two peptide fragments and connected them by the copper-mediated alkyne and azide cycloaddition (CuAAC) reaction. Cyclization was performed by bis-thioether linkage using 1,3-dibromomethyl-5-propargyloxybenzene, and subsequently, the cHLH peptide was labeled with an azide-labeled probe. Finally, we designed and synthesized a peptide inhibitor for the p53-HDM2 interaction using a structure-guided design and successfully labeled it with a fluorescent probe or a functional peptide, respectively, by click chemistry. This macrocyclization and labeling method for cHLH peptide would facilitate the discovery of de novo bioactive ligands and therapeutic leads. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 415-421, 2016. PMID:26917088

  15. Two single nucleotide polymorphisms in the human nescient helix-loop-helix 2 (NHLH2) gene reduce mRNA stability and DNA binding.

    PubMed

    Al Rayyan, Numan; Wankhade, Umesh D; Bush, Korie; Good, Deborah J

    2013-01-01

    Nescient helix-loop-helix-2 (NHLH2) is a basic helix-loop-helix transcription factor, which has been implicated, using mouse knockouts, in adult body weight regulation and fertility. A scan of the known single nucleotide polymorphisms (SNPs) in the NHLH2 gene revealed one in the 3' untranslated region (3'UTR), which lies within an AUUUA RNA stability motif. A second SNP is nonsynonymous within the coding region of NHLH2, and was found in a genome-wide association study for obesity. Both of these SNPs were examined for their effect on NLHL2 by creating mouse mimics and examining mRNA stability, and protein function in mouse hypothalamic cell lines. The 3'UTR SNP causes increased instability and, when the SNP-containing Nhlh2 3'UTR is attached to luciferase mRNA, reduced protein levels in cells. The nonsynonymous SNP at position 83 in the protein changes an alanine residue, conserved in NHLH2 orthologs through the Drosophila sp. to a proline residue. This change affects migration of the protein on an SDS-PAGE gel, and appears to alter secondary structure of the protein, as predicted using in silico methods. These results provide functional information on two rare human SNPs in the NHLH2 gene. One of these has been linked to human obese phenotypes, while the other is present in a relatively high proportion of individuals. Given their effects on NHLH2 protein levels, both SNPs deserve further analysis in whether they are causative and/or additive for human body weight and fertility phenotypes. PMID:23026212

  16. The basic helix-loop-helix transcription factor family in the sacred lotus, Nelumbo nucifera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nelumbo nucifera (Sacred Lotus) is a basal eudicot with exceptional physiological and metabolic properties including seed longevity, adaptations for an aquatic habit, and floral thermiogenesis. It also occupies a unique position in the phylogeny of land plants and can be a useful species for studies...

  17. Net (ERP/SAP2) one of the Ras-inducible TCFs, has a novel inhibitory domain with resemblance to the helix-loop-helix motif.

    PubMed

    Maira, S M; Wurtz, J M; Wasylyk, B

    1996-11-01

    The three ternary complex factors (TCFs), Net (ERP/ SAP-2), ELK-1 and SAP-1, are highly related ets oncogene family members that participate in the response of the cell to Ras and growth signals. Understanding the different roles of these factors will provide insights into how the signals result in coordinate regulation of the cell. We show that Net inhibits transcription under basal conditions, in which SAP-1a is inactive and ELK-1 stimulates. Repression is mediated by the NID, the Net Inhibitory Domain of about 50 amino acids, which autoregulates the Net protein and also inhibits when it is isolated in a heterologous fusion protein. Net is particularly sensitive to Ras activation. Ras activates Net through the C-domain, which is conserved between the three TCFs, and the NID is an efficient inhibitor of Ras activation. The NID, as well as more C-terminal sequences, inhibit DNA binding. Net is more refractory to DNA binding than the other TCFs, possibly due to the presence of multiple inhibitory elements. The NID may adopt a helix-loop-helix (HLH) structure, as evidenced by homology to other HLH motifs, structure predictions, model building and mutagenesis of critical residues. The sequence resemblance with myogenic factors suggested that Net may form complexes with the same partners. Indeed, we found that Net can interact in vivo with the basic HLH factor, E47. We propose that Net is regulated at the level of its latent DNA-binding activity by protein interactions and/or phosphorylation. Net may form complexes with HLH proteins as well as SRF on specific promotor sequences. The identification of the novel inhibitory domain provides a new inroad into exploring the different roles of the ternary complex factors in growth control and transformation. PMID:8918463

  18. A novel initiator regulates expression of the nontissue-specific helix-loop-helix gene ME1.

    PubMed Central

    Shain, D H; Neuman, T; Zuber, M X

    1995-01-01

    The mouse ME1 gene (HEB, REB and GE1, homologues in human, rat and chick, respectively) is a member of the nontissue-specific helix-loop-helix (HLH) gene family that includes E2A, E2-2 and Drosophila daughterless. We have examined the factors that control ME1 gene expression. ME1 is a single copy gene that spans > or = 150 kb of DNA and contains > 10 exons. Transcription was directed by an unusual initiator element that contained a 13 bp poly d(A) tract flanked by palindromic and inverted repeat sequences. Both RNase protection and primer extension analyses mapped the ME1 transcriptional start site to the center of the 13 bp poly d(A) tract. The ME1 initiator and its proximal sequences were required for promoter activity, supported basal levels of transcription, and contributed to cell type-specific gene expression. Other cis-elements utilized by the TATA-less ME1 promoter included a cluster of Sp1 response elements, E-boxes and a strong repressor. Collectively, our results suggest that the ME1 initiator and other cis-elements in the proximal promoter play an important role in regulating ME1 gene expression. Images PMID:7784173

  19. Peptide and metal ion-dependent association of isolated helix-loop-helix calcium binding domains: studies of thrombic fragments of calmodulin.

    PubMed Central

    Brokx, R. D.; Vogel, H. J.

    2000-01-01

    Calmodulin (CaM), the ubiquitous, eukaryotic, bilobal calcium-binding regulatory protein, has been cleaved by thrombin to create two fragments. TM1 (1-106) and TM2 (107-148). NMR and CD results indicate that TMI and TM2 can associate in the presence of Ca2+ to form a complex similar to native CaM, even though the cleavage site is not in the linker region between two helix-loop-helix domains, but rather within an alpha-helix. Cadmium-113 NMR results show that this complex has enhanced metal-ion binding properties when compared to either TM1 or TM2 alone. This complex can bind several CaM-binding target peptides, as shown by gel bandshift assays, circular dichroism spectra, and 13C NMR spectra of biosynthetically methyl-13C-Met-labeled TM1 and TM2; moreover, gel bandshift assays show that the addition of a target peptide strengthens the interactions between TM1 and TM2 and increases the stability of the complex. Cadmium-113 NMR spectra indicate that the TM1:TM2 complex can also bind the antipsychotic drug trifluoperazine. However, in contrast to CaM:peptide complexes, the TM1:TM2:peptide complexes are disrupted by 4 M urea; moreover, TM1 and TM2 in combination are unable to activate CaM-dependent enzymes. This suggests that TM1:TM2 mixtures cannot bind target molecules as tightly as intact CaM, or perhaps that binding occurs but additional interactions with the target enzymes that are necessary for proper activation are perturbed by the proteolytic cleavage. The results presented here reflect the importance of the existence of helix-loop-helix Ca2+-binding domains in pairs in proteins such as CaM, and extend the understanding of the association of such domains in this class of proteins in general. PMID:10850806

  20. Characterization of npas3, a novel basic helix-loop-helix PAS gene expressed in the developing mouse nervous system.

    PubMed

    Brunskill, E W; Witte, D P; Shreiner, A B; Potter, S S

    1999-11-01

    Here we describe the cloning and expression pattern of a new bHLH-PAS domain gene, Npas3. Npas3 shares 50.2% amino acid sequence identity with Npas1 and a lesser similarity with other members of the bHLH-PAS domain family of transcription factors. Northern blot analysis detected Npas3 mRNA between 11.5 and 17.5 d.p.c. in embryonic development and exclusively in the adult brain. Whole-mount and section in situ hybridization assays revealed expression of Npas3 between 9.5 and 11.5 d.p.c. in the developing neural tube. In addition, Npas3 mRNA was expressed throughout the neuroepithelium of the developing central nervous system between 10. 5 and 12.5 d.p.c. Interestingly, at 14.5 d.p.c., the expression of Npas3 mRNA became restricted to the neopallial layer of the cortex. At 12.5 d.p.c., Npas3 mRNA was evident in nonneural tissues such as the developing dermis and mesenchyme surrounding the otic and nasal placodes. Expression was also detected in the developing cardiac valves, limb and developing kidney. PMID:10534623

  1. A Divalent Ion Is Crucial in the Structure and Dominant-Negative Function of ID Proteins, a Class of Helix-Loop-Helix Transcription Regulators

    PubMed Central

    Palasingam, Paaventhan; Kolatkar, Prasanna R.

    2012-01-01

    Inhibitors of DNA binding and differentiation (ID) proteins, a dominant-negative group of helix-loop-helix (HLH) transcription regulators, are well-characterized key players in cellular fate determination during development in mammals as well as Drosophila. Although not oncogenes themselves, their upregulation by various oncogenic proteins (such as Ras, Myc) and their inhibitory effects on cell cycle proteins (such as pRb) hint at their possible roles in tumorigenesis. Furthermore, their potency as inhibitors of cellular differentiation, through their heterodimerization with subsequent inactivation of the ubiquitous E proteins, suggest possible novel roles in engineering induced pluripotent stem cells (iPSCs). We present the high-resolution 2.1Å crystal structure of ID2 (HLH domain), coupled with novel biochemical insights in the presence of a divalent ion, possibly calcium (Ca2+), in the loop of ID proteins, which appear to be crucial for the structure and activity of ID proteins. These new insights will pave the way for new rational drug designs, in addition to current synthetic peptide options, against this potent player in tumorigenesis as well as more efficient ways for stem cells reprogramming. PMID:23119064

  2. A Cyclized Helix-Loop-Helix Peptide as a Molecular Scaffold for the Design of Inhibitors of Intracellular Protein-Protein Interactions by Epitope and Arginine Grafting.

    PubMed

    Fujiwara, Daisuke; Kitada, Hidekazu; Oguri, Masahiro; Nishihara, Toshio; Michigami, Masataka; Shiraishi, Kazunori; Yuba, Eiji; Nakase, Ikuhiko; Im, Haeri; Cho, Sunhee; Joung, Jong Young; Kodama, Seiji; Kono, Kenji; Ham, Sihyun; Fujii, Ikuo

    2016-08-26

    The design of inhibitors of intracellular protein-protein interactions (PPIs) remains a challenge in chemical biology and drug discovery. We propose a cyclized helix-loop-helix (cHLH) peptide as a scaffold for generating cell-permeable PPI inhibitors through bifunctional grafting: epitope grafting to provide binding activity, and arginine grafting to endow cell-permeability. To inhibit p53-HDM2 interactions, the p53 epitope was grafted onto the C-terminal helix and six Arg residues were grafted onto another helix. The designed peptide cHLHp53-R showed high inhibitory activity for this interaction, and computational analysis suggested a binding mode for HDM2. Confocal microscopy of cells treated with fluorescently labeled cHLHp53-R revealed cell membrane penetration and cytosolic localization. The peptide inhibited the growth of HCT116 and LnCap cancer cells. This strategy of bifunctional grafting onto a well-structured peptide scaffold could facilitate the generation of inhibitors for intracellular PPIs. PMID:27467415

  3. Reovirus FAST Proteins Drive Pore Formation and Syncytiogenesis Using a Novel Helix-Loop-Helix Fusion-Inducing Lipid Packing Sensor

    PubMed Central

    Sarker, Muzaddid; de Antueno, Roberto; Langelaan, David N.; Parmar, Hiren B.; Shin, Kyungsoo; Rainey, Jan K.; Duncan, Roy

    2015-01-01

    Pore formation is the most energy-demanding step during virus-induced membrane fusion, where high curvature of the fusion pore rim increases the spacing between lipid headgroups, exposing the hydrophobic interior of the membrane to water. How protein fusogens breach this thermodynamic barrier to pore formation is unclear. We identified a novel fusion-inducing lipid packing sensor (FLiPS) in the cytosolic endodomain of the baboon reovirus p15 fusion-associated small transmembrane (FAST) protein that is essential for pore formation during cell-cell fusion and syncytiogenesis. NMR spectroscopy and mutational studies indicate the dependence of this FLiPS on a hydrophobic helix-loop-helix structure. Biochemical and biophysical assays reveal the p15 FLiPS preferentially partitions into membranes with high positive curvature, and this partitioning is impeded by bis-ANS, a small molecule that inserts into hydrophobic defects in membranes. Most notably, the p15 FLiPS can be functionally replaced by heterologous amphipathic lipid packing sensors (ALPS) but not by other membrane-interactive amphipathic helices. Furthermore, a previously unrecognized amphipathic helix in the cytosolic domain of the reptilian reovirus p14 FAST protein can functionally replace the p15 FLiPS, and is itself replaceable by a heterologous ALPS motif. Anchored near the cytoplasmic leaflet by the FAST protein transmembrane domain, the FLiPS is perfectly positioned to insert into hydrophobic defects that begin to appear in the highly curved rim of nascent fusion pores, thereby lowering the energy barrier to stable pore formation. PMID:26061049

  4. Significant dissociation of expression patterns of the basic helix-loop-helix transcription factors Dec1 and Dec2 in rat kidney.

    PubMed

    Wu, Tao; Ni, Yinhua; Zhuge, Fen; Sun, Lu; Xu, Bin; Kato, Hisanori; Fu, Zhengwei

    2011-04-15

    Dec1 and Dec2 are regulators of the mammalian molecular clock that show robust circadian rhythms in the suprachiasmatic nucleus and various peripheral tissues. Although the expression of Dec1 and Dec2 is altered by multiple stimuli in different organs, their transcriptional regulatory mechanisms have not been fully elucidated for the kidney. In the present study, we describe for the first time significant dissociation of expression patterns with arrhythmic expression of Dec1 and rhythmic expression of Dec2 in rat kidney under a normal light-dark (LD) cycle. Daytime restricted feeding (RF) significantly altered the expression patterns of these two clock genes, and even induced circadian expression of Dec1 with an amplitude of 2.2 on day 3 and 4.2 on day 7. However, when a reversed feeding schedule was coupled with a reversed LD cycle, the expression of Dec1 but not Dec2 reverted to being arrhythmic. Moreover, exogenous injection of the glucocorticoid analogue dexamethasone (Dex) at certain times of the day resulted in rhythmic expression of Dec1, which was similar to that seen following RF for 7 days. In contrast, endogenous disruption of glucocorticoids by adrenalectomy abolished RF-induced rhythmic expression of Dec1 in the kidney. These observations suggest the existence of a glucocorticoid gating mechanism in the circadian expression of Dec1 in rat kidney. PMID:21430201

  5. Human variants in the neuronal basic helix-loop-helix/Per-Arnt-Sim (bHLH/PAS) transcription factor complex NPAS4/ARNT2 disrupt function.

    PubMed

    Bersten, David C; Bruning, John B; Peet, Daniel J; Whitelaw, Murray L

    2014-01-01

    Neuronal Per-Arnt-Sim homology (PAS) Factor 4 (NPAS4) is a neuronal activity-dependent transcription factor which heterodimerises with ARNT2 to regulate genes involved in inhibitory synapse formation. NPAS4 functions to maintain excitatory/inhibitory balance in neurons, while mouse models have shown it to play roles in memory formation, social interaction and neurodegeneration. NPAS4 has therefore been implicated in a number of neuropsychiatric or neurodegenerative diseases which are underpinned by defects in excitatory/inhibitory balance. Here we have explored a broad set of non-synonymous human variants in NPAS4 and ARNT2 for disruption of NPAS4 function. We found two variants in NPAS4 (F147S and E257K) and two variants in ARNT2 (R46W and R107H) which significantly reduced transcriptional activity of the heterodimer on a luciferase reporter gene. Furthermore, we found that NPAS4.F147S was unable to activate expression of the NPAS4 target gene BDNF due to reduced dimerisation with ARNT2. Homology modelling predicts F147 in NPAS4 to lie at the dimer interface, where it appears to directly contribute to protein/protein interaction. We also found that reduced transcriptional activation by ARNT2 R46W was due to disruption of nuclear localisation. These results provide insight into the mechanisms of NPAS4/ARNT dimerisation and transcriptional activation and have potential implications for cognitive phenotypic variation and diseases such as autism, schizophrenia and dementia. PMID:24465693

  6. Human Variants in the Neuronal Basic Helix-Loop-Helix/Per-Arnt-Sim (bHLH/PAS) Transcription Factor Complex NPAS4/ARNT2 Disrupt Function

    PubMed Central

    Bersten, David C.; Bruning, John B.; Peet, Daniel J.; Whitelaw, Murray L.

    2014-01-01

    Neuronal Per-Arnt-Sim homology (PAS) Factor 4 (NPAS4) is a neuronal activity-dependent transcription factor which heterodimerises with ARNT2 to regulate genes involved in inhibitory synapse formation. NPAS4 functions to maintain excitatory/inhibitory balance in neurons, while mouse models have shown it to play roles in memory formation, social interaction and neurodegeneration. NPAS4 has therefore been implicated in a number of neuropsychiatric or neurodegenerative diseases which are underpinned by defects in excitatory/inhibitory balance. Here we have explored a broad set of non-synonymous human variants in NPAS4 and ARNT2 for disruption of NPAS4 function. We found two variants in NPAS4 (F147S and E257K) and two variants in ARNT2 (R46W and R107H) which significantly reduced transcriptional activity of the heterodimer on a luciferase reporter gene. Furthermore, we found that NPAS4.F147S was unable to activate expression of the NPAS4 target gene BDNF due to reduced dimerisation with ARNT2. Homology modelling predicts F147 in NPAS4 to lie at the dimer interface, where it appears to directly contribute to protein/protein interaction. We also found that reduced transcriptional activation by ARNT2 R46W was due to disruption of nuclear localisation. These results provide insight into the mechanisms of NPAS4/ARNT dimerisation and transcriptional activation and have potential implications for cognitive phenotypic variation and diseases such as autism, schizophrenia and dementia. PMID:24465693

  7. Amino-terminal domains of c-myc and N-myc proteins mediate binding to the retinoblastoma gene product

    NASA Astrophysics Data System (ADS)

    Rustgi, Anil K.; Dyson, Nicholas; Bernards, Rene

    1991-08-01

    THE proteins encoded by the myc gene family are involved in the control of cell proliferation and differentiation, and aberrant expression of myc proteins has been implicated in the genesis of a variety of neoplasms1. In the carboxyl terminus, myc proteins have two domains that encode a basic domain/helix-loop-helix and a leucine zipper motif, respectively. These motifs are involved both in DNA binding and in protein dimerization2-5. In addition, myc protein family members share several regions of highly conserved amino acids in their amino termini that are essential for transformation6,7. We report here that an N-terminal domain present in both the c-myc and N-myc proteins mediates binding to the retinoblastoma gene product, pRb. We show that the human papilloma virus E7 protein competes with c-myc for binding to pRb, indicating that these proteins share overlapping binding sites on pRb. Furthermore, a mutant Rb protein from a human tumour cell line that carried a 35-amino-acid deletion in its C terminus failed to bind to c-myc. Our results suggest that c-myc and pRb cooperate through direct binding to control cell proliferation.

  8. Specificity for the Hairy/enhancer of split basic helix-loop-helix (bHLH) proteins maps outside the bHLH domain and suggests two separable modes of transcriptional repression

    SciTech Connect

    Dawson, S.R.; Turner, D.L.; Weintraub, H.; Parkhurst, S.M.

    1995-12-01

    This report investigates transcriptional repressors in Drosophila melanogaster and their function in and effect on developmental processes such as sex determination. Details on the mechanism of function of these transcriptional repressors are also discussed. 50 refs., 3 figs., 4 tabs.

  9. Overexpression of a citrus basic helix-loop-helix transcription factor (CubHLH1), which is homologous to Arabidopsis activation-tagged bri1 suppressor 1 interacting factor genes, modulates carotenoid metabolism in transgenic tomato.

    PubMed

    Endo, Tomoko; Fujii, Hiroshi; Sugiyama, Aiko; Nakano, Michiharu; Nakajima, Naoko; Ikoma, Yoshinori; Omura, Mitsuo; Shimada, Takehiko

    2016-02-01

    To explore the transcription factors associated with carotenoid metabolism in citrus fruit, one transcription factor (CubHLH1) was selected through microarray screening in Satsuma mandarin (Citrus unshiu Marc.) fruit, which was treated with exogenous ethylene or gibberellin (GA), accelerating or retarding carotenoid accumulation in peel, respectively. The amino acid sequence of CubHLH1 has homology to Arabidopsis activation-tagged bri1 suppressor 1 (ATBS1) interacting factor (AIF), which is functionally characterized as a negative regulator of the brassinolide (BR) signalling pathway. Yeast two-hybrid analysis revealed that protein for CubHLH1 could interact with Arabidopsis and tomato ATBS1. Overexpression of CubHLH1 caused a dwarf phenotype in transgenic tomato (Solanum lycopersicum L.), suggesting that CubHLH1 has a similar function to Arabidopsis AIF. In the transgenic tomato fruit at ripening stage, the lycopene content was reduced along with the changes in carotenoid biosynthetic gene expression. The abscisic acid (ABA) content of all the transgenic tomato fruit was higher than that of the wild type. These results implied that CubHLH1 is considered to have a similar function to Arabidopsis AIFs and might be directly involved in carotenoid metabolism in mature citrus fruit. PMID:26795149

  10. Functional diversification of the potato R2R3 MYB anthocyanin activators AN1, MYBA1, and MYB113 and their interaction with basic helix-loop-helix cofactors.

    PubMed

    Liu, Yuhui; Lin-Wang, Kui; Espley, Richard V; Wang, Li; Yang, Hongyu; Yu, Bin; Dare, Andrew; Varkonyi-Gasic, Erika; Wang, Jing; Zhang, Junlian; Wang, Di; Allan, Andrew C

    2016-04-01

    In potato (Solanum tuberosumL.), R2R3 MYBs are involved in the regulation of anthocyanin biosynthesis. We examined sequences of these MYBs in cultivated potatoes, which are more complex than diploid potato due to ploidy and heterozygosity. We found amino acid variants in the C-terminus of the MYB StAN1, termed R0, R1, and R3, due to the presence of a repeated 10-amino acid motif. These variant MYBs showed some expression in both white and pigmented tubers. We found several new alleles or gene family members of R2R3 MYBs,StMYBA1andStMYB113, which were also expressed in white potato tubers. From functional analysis in tobacco, we showed that the presence of a C-terminal 10-amino acid motif is optimal for activating anthocyanin accumulation. Engineering a motif back into a MYB lacking this sequence enhanced its activating ability. Versions ofStMYBA1andStMYB113can also activate anthocyanin accumulation in tobacco leaves, with the exception ofStMYB113-3, which has a partial R2R3 domain. We isolated five family members of potatoStbHLH1, and oneStJAF13, to test their ability to interact with MYB variants. The results showed that two alleles ofStbHLH1from white skin and red skin are non-functional, while three otherStbHLH1s have different co-regulating abilities, and need to be activated by StJAF13. Combined with expression analysis in potato tuber, results suggest thatStbHLH1andStJAF13are key co-regulators of anthocyanin biosynthesis, while the transcripts of MYB variantsStAN1,StMYBA1, andStMYB113are well expressed, even in the absence of pigmentation. PMID:26884602

  11. Functional diversification of the potato R2R3 MYB anthocyanin activators AN1, MYBA1, and MYB113 and their interaction with basic helix-loop-helix cofactors

    PubMed Central

    Liu, Yuhui; Lin-Wang, Kui; Espley, Richard V.; Wang, Li; Yang, Hongyu; Yu, Bin; Dare, Andrew; Varkonyi-Gasic, Erika; Wang, Jing; Zhang, Junlian; Wang, Di; Allan, Andrew C.

    2016-01-01

    In potato (Solanum tuberosum L.), R2R3 MYBs are involved in the regulation of anthocyanin biosynthesis. We examined sequences of these MYBs in cultivated potatoes, which are more complex than diploid potato due to ploidy and heterozygosity. We found amino acid variants in the C-terminus of the MYB StAN1, termed R0, R1, and R3, due to the presence of a repeated 10-amino acid motif. These variant MYBs showed some expression in both white and pigmented tubers. We found several new alleles or gene family members of R2R3 MYBs, StMYBA1 and StMYB113, which were also expressed in white potato tubers. From functional analysis in tobacco, we showed that the presence of a C-terminal 10-amino acid motif is optimal for activating anthocyanin accumulation. Engineering a motif back into a MYB lacking this sequence enhanced its activating ability. Versions of StMYBA1 and StMYB113 can also activate anthocyanin accumulation in tobacco leaves, with the exception of StMYB113-3, which has a partial R2R3 domain. We isolated five family members of potato StbHLH1, and one StJAF13, to test their ability to interact with MYB variants. The results showed that two alleles of StbHLH1 from white skin and red skin are non-functional, while three other StbHLH1s have different co-regulating abilities, and need to be activated by StJAF13. Combined with expression analysis in potato tuber, results suggest that StbHLH1 and StJAF13 are key co-regulators of anthocyanin biosynthesis, while the transcripts of MYB variants StAN1, StMYBA1, and StMYB113 are well expressed, even in the absence of pigmentation. PMID:26884602

  12. Responses of a triple mutant defective in three iron deficiency-induced Basic Helix-Loop-Helix genes of the subgroup Ib(2) to iron deficiency and salicylic acid.

    PubMed

    Maurer, Felix; Naranjo Arcos, Maria Augusta; Bauer, Petra

    2014-01-01

    Plants are sessile organisms that adapt to external stress by inducing molecular and physiological responses that serve to better cope with the adverse growth condition. Upon low supply of the micronutrient iron, plants actively increase the acquisition of soil iron into the root and its mobilization from internal stores. The subgroup Ib(2) BHLH genes function as regulators in this response, however their concrete functions are not fully understood. Here, we analyzed a triple loss of function mutant of BHLH39, BHLH100 and BHLH101 (3xbhlh mutant). We found that this mutant did not have any iron uptake phenotype if iron was provided. However, under iron deficiency the mutant displayed a more severe leaf chlorosis than the wild type. Microarray-based transcriptome analysis revealed that this mutant phenotype resulted in the mis-regulation of 198 genes, out of which only 15% were associated with iron deficiency regulation itself. A detailed analysis revealed potential targets of the bHLH transcription factors as well as genes reflecting an exaggerated iron deficiency response phenotype. Since the BHLH genes of this subgroup have been brought into the context of the plant hormone salicylic acid, we investigated whether the 3xbhlh mutant might have been affected by this plant signaling molecule. Although a very high number of genes responded to SA, also in a differential manner between mutant and wild type, we did not find any indication for an association of the BHLH gene functions in SA responses upon iron deficiency. In summary, our study indicates that the bHLH subgroup Ib(2) transcription factors do not only act in iron acquisition into roots but in other aspects of the adaptation to iron deficiency in roots and leaves. PMID:24919188

  13. Responses of a Triple Mutant Defective in Three Iron Deficiency-Induced BASIC HELIX-LOOP-HELIX Genes of the Subgroup Ib(2) to Iron Deficiency and Salicylic Acid

    PubMed Central

    Maurer, Felix; Naranjo Arcos, Maria Augusta; Bauer, Petra

    2014-01-01

    Plants are sessile organisms that adapt to external stress by inducing molecular and physiological responses that serve to better cope with the adverse growth condition. Upon low supply of the micronutrient iron, plants actively increase the acquisition of soil iron into the root and its mobilization from internal stores. The subgroup Ib(2) BHLH genes function as regulators in this response, however their concrete functions are not fully understood. Here, we analyzed a triple loss of function mutant of BHLH39, BHLH100 and BHLH101 (3xbhlh mutant). We found that this mutant did not have any iron uptake phenotype if iron was provided. However, under iron deficiency the mutant displayed a more severe leaf chlorosis than the wild type. Microarray-based transcriptome analysis revealed that this mutant phenotype resulted in the mis-regulation of 198 genes, out of which only 15% were associated with iron deficiency regulation itself. A detailed analysis revealed potential targets of the bHLH transcription factors as well as genes reflecting an exaggerated iron deficiency response phenotype. Since the BHLH genes of this subgroup have been brought into the context of the plant hormone salicylic acid, we investigated whether the 3xbhlh mutant might have been affected by this plant signaling molecule. Although a very high number of genes responded to SA, also in a differential manner between mutant and wild type, we did not find any indication for an association of the BHLH gene functions in SA responses upon iron deficiency. In summary, our study indicates that the bHLH subgroup Ib(2) transcription factors do not only act in iron acquisition into roots but in other aspects of the adaptation to iron deficiency in roots and leaves. PMID:24919188

  14. The Helix-Loop-Helix Protein ID2 Governs NK Cell Fate by Tuning Their Sensitivity to Interleukin-15.

    PubMed

    Delconte, Rebecca B; Shi, Wei; Sathe, Priyanka; Ushiki, Takashi; Seillet, Cyril; Minnich, Martina; Kolesnik, Tatiana B; Rankin, Lucille C; Mielke, Lisa A; Zhang, Jian-Guo; Busslinger, Meinrad; Smyth, Mark J; Hutchinson, Dana S; Nutt, Stephen L; Nicholson, Sandra E; Alexander, Warren S; Corcoran, Lynn M; Vivier, Eric; Belz, Gabrielle T; Carotta, Sebastian; Huntington, Nicholas D

    2016-01-19

    The inhibitor of DNA binding 2 (Id2) is essential for natural killer (NK) cell development with its canonical role being to antagonize E-protein function and alternate lineage fate. Here we have identified a key role for Id2 in regulating interleukin-15 (IL-15) receptor signaling and homeostasis of NK cells by repressing multiple E-protein target genes including Socs3. Id2 deletion in mature NK cells was incompatible with their homeostasis due to impaired IL-15 receptor signaling and metabolic function and this could be rescued by strong IL-15 receptor stimulation or genetic ablation of Socs3. During NK cell maturation, we observed an inverse correlation between E-protein target genes and Id2. These results shift the current paradigm on the role of ID2, indicating that it is required not only to antagonize E-proteins during NK cell commitment, but constantly required to titrate E-protein activity to regulate NK cell fitness and responsiveness to IL-15. PMID:26795246

  15. Identifying Novel Helix-Loop-Helix Genes in "Caenorhabditis elegans" through a Classroom Demonstration of Functional Genomics

    ERIC Educational Resources Information Center

    Griffin, Vernetta; McMiller, Tracee; Jones, Erika; Johnson, Casonya M.

    2003-01-01

    A 14-week, undergraduate-level Genetics and Population Biology course at Morgan State University was modified to include a demonstration of functional genomics in the research laboratory. Students performed a rudimentary sequence analysis of the "Caenorhabditis elegans" genome and further characterized three sequences that were predicted to encode…

  16. Protein kinase C modulates aryl hydrocarbon receptor nuclear translocator protein-mediated transactivation potential in a dimer context.

    PubMed

    Long, W P; Chen, X; Perdew, G H

    1999-04-30

    Protein kinase C (PKC)- and protein kinase A (PKA)-mediated modulation of the transactivation potential of human aryl hydrocarbon receptor nuclear translocator (hARNT), a basic helix-loop-helix (bHLH)-PAS transcription factor, and the bHLH-ZIP transcription factors USF-1 (for upstream regulatory factor 1) and c-Myc were examined. An 81 nM dose of the PKC activator phorbol-12-myristate-13-acetate (PMA), shown here to specifically activate PKC in COS-1 cells, or a 1 nM dose of the PKA activator 8-bromoadenosine-3',5'-cyclic monophosphate (8-Br-cAMP) results in 2. 6- and 1.9-fold enhancements, respectively, in hARNT-mediated transactivation of the class B, E-box-driven reporter pMyc3E1bLuc relative to identically transfected, carrier solvent-treated COS-1 cells. In contrast, 81 nM PMA and 1 nM 8-Br-cAMP did not enhance transactivation of pMyc3E1bLuc-driven by USF-1 and c-Myc expression relative to identically transfected, carrier-treated COS-1 cells. Co-transfection of pcDNA3/ARNT-474-Flag, expressing a hARNT carboxyl-terminal transactivation domain deletion, and pMyc3E1bLuc does not result in induction of reporter activity, suggesting PMA's effects do not involve formation of unknown hARNT-protein heterodimers. Additionally, PMA had no effect on hARNT expression relative to Me2SO-treated cells. Metabolic 32P labeling of hARNT in cells treated with carrier solvent or 81 nM PMA demonstrates that PMA does not increase the overall phosphorylation level of hARNT. These results demonstrate, for the first time, that the transactivation potential of ARNT in a dimer context can be specifically modulated by PKC or PKA stimulation and that the bHLH-PAS and bHLH-ZIP transcription factors are differentially regulated by these pathways in COS-1 cells. PMID:10212212

  17. Novel and recurrent non-truncating mutations of the MITF basic domain: genotypic and phenotypic variations in Waardenburg and Tietz syndromes.

    PubMed

    Léger, Sandy; Balguerie, Xavier; Goldenberg, Alice; Drouin-Garraud, Valérie; Cabot, Annick; Amstutz-Montadert, Isabelle; Young, Paul; Joly, Pascal; Bodereau, Virginie; Holder-Espinasse, Muriel; Jamieson, Robyn V; Krause, Amanda; Chen, Hongsheng; Baumann, Clarisse; Nunes, Luis; Dollfus, Hélène; Goossens, Michel; Pingault, Véronique

    2012-05-01

    The microphthalmia-associated transcription factor (MITF) is a basic helix-loop-helix leucine zipper transcription factor, which regulates melanocyte development and the biosynthetic melanin pathway. A notable relationship has been described between non-truncating mutations of its basic domain and Tietz syndrome, which is characterized by albinoid-like hypopigmentation of the skin and hair, rather than the patchy depigmentation seen in Waardenburg syndrome, and severe hearing loss. Twelve patients with new or recurrent non-truncating mutations of the MITF basic domain from six families were enrolled in this study. We observed a wide range of phenotypes and some unexpected features. All the patients had blue irides and pigmentation abnormalities that ranged from diffuse hypopigmentation to Waardenburg-like patches. In addition, they showed congenital complete hearing loss, diffuse hypopigmentation of the skin, freckling and ocular abnormalities, more frequently than patients with MITF mutations outside the basic domain. In conclusion, the non-truncating mutations of the basic domain do not always lead to Tietz syndrome but rather to a large range of phenotypes. Sun-exposed freckles are interestingly observed more frequently in Asian populations. This variability argues for the possible interaction with modifier loci. PMID:22258527

  18. Recurrent Mutations in the Basic Domain of TWIST2 Cause Ablepharon Macrostomia and Barber-Say Syndromes.

    PubMed

    Marchegiani, Shannon; Davis, Taylor; Tessadori, Federico; van Haaften, Gijs; Brancati, Francesco; Hoischen, Alexander; Huang, Haigen; Valkanas, Elise; Pusey, Barbara; Schanze, Denny; Venselaar, Hanka; Vulto-van Silfhout, Anneke T; Wolfe, Lynne A; Tifft, Cynthia J; Zerfas, Patricia M; Zambruno, Giovanna; Kariminejad, Ariana; Sabbagh-Kermani, Farahnaz; Lee, Janice; Tsokos, Maria G; Lee, Chyi-Chia R; Ferraz, Victor; da Silva, Eduarda Morgana; Stevens, Cathy A; Roche, Nathalie; Bartsch, Oliver; Farndon, Peter; Bermejo-Sanchez, Eva; Brooks, Brian P; Maduro, Valerie; Dallapiccola, Bruno; Ramos, Feliciano J; Chung, Hon-Yin Brian; Le Caignec, Cédric; Martins, Fabiana; Jacyk, Witold K; Mazzanti, Laura; Brunner, Han G; Bakkers, Jeroen; Lin, Shuo; Malicdan, May Christine V; Boerkoel, Cornelius F; Gahl, William A; de Vries, Bert B A; van Haelst, Mieke M; Zenker, Martin; Markello, Thomas C

    2015-07-01

    Ablepharon macrostomia syndrome (AMS) and Barber-Say syndrome (BSS) are rare congenital ectodermal dysplasias characterized by similar clinical features. To establish the genetic basis of AMS and BSS, we performed extensive clinical phenotyping, whole exome and candidate gene sequencing, and functional validations. We identified a recurrent de novo mutation in TWIST2 in seven independent AMS-affected families, as well as another recurrent de novo mutation affecting the same amino acid in ten independent BSS-affected families. Moreover, a genotype-phenotype correlation was observed, because the two syndromes differed based solely upon the nature of the substituting amino acid: a lysine at TWIST2 residue 75 resulted in AMS, whereas a glutamine or alanine yielded BSS. TWIST2 encodes a basic helix-loop-helix transcription factor that regulates the development of mesenchymal tissues. All identified mutations fell in the basic domain of TWIST2 and altered the DNA-binding pattern of Flag-TWIST2 in HeLa cells. Comparison of wild-type and mutant TWIST2 expressed in zebrafish identified abnormal developmental phenotypes and widespread transcriptome changes. Our results suggest that autosomal-dominant TWIST2 mutations cause AMS or BSS by inducing protean effects on the transcription factor's DNA binding. PMID:26119818

  19. A smallest 6 kda metalloprotease, mini-matrilysin, in living world: a revolutionary conserved zinc-dependent proteolytic domain- helix-loop-helix catalytic zinc binding domain (ZBD)

    PubMed Central

    2012-01-01

    Background The Aim of this study is to study the minimum zinc dependent metalloprotease catalytic folding motif, helix B Met loop-helix C, with proteolytic catalytic activities in metzincin super family. The metzincin super family share a catalytic domain consisting of a twisted five-stranded β sheet and three long α helices (A, B and C). The catalytic zinc is at the bottom of the cleft and is ligated by three His residues in the consensus sequence motif, HEXXHXXGXXH, which is located in helix B and part of the adjacent Met turn region. An interesting question is - what is the minimum portion of the enzyme that still possesses catalytic and inhibitor recognition?” Methods We have expressed a 60-residue truncated form of matrilysin which retains only the helix B-Met turn-helix C region and deletes helix A and the five-stranded β sheet which form the upper portion of the active cleft. This is only 1/4 of the full catalytic domain. The E. coli derived 6 kDa MMP-7 ZBD fragments were purified and refolded. The proteolytic activities were analyzed by Mca-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2 peptide assay and CM-transferrin zymography analysis. SC44463, BB94 and Phosphoramidon were computationally docked into the 3day structure of the human MMP7 ZBD and TAD and thermolysin using the docking program GOLD. Results This minimal 6 kDa matrilysin has been refolded and shown to have proteolytic activity in the Mca-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2 peptide assay. Triton X-100 and heparin are important factors in the refolding environment for this mini-enzyme matrilysin. This minienzyme has the proteolytic activity towards peptide substrate, but the hexamer and octamer of the mini MMP-7 complex demonstrates the CM-transferrin proteolytic activities in zymographic analysis. Peptide digestion is inhibited by SC44463, specific MMP7 inhibitors, but not phosphorimadon. Interestingly, the mini MMP-7 can be processed by autolysis and producing ~ 6 ~ 7 kDa fragments. Thus, many of the functions of the enzyme are retained indicating that the helix B-Met loop-helix C is the minimal functional “domain” found to date for the matrixin family. Conclusions The helix B-Met loop-helix C folding conserved in metalloprotease metzincin super family is able to facilitate proteolytic catalysis for specific substrate and inhibitor recognition. The autolysis processing and producing 6 kDa mini MMP-7 is the smallest metalloprotease in living world. PMID:22642296

  20. Multiscale Simulation of Protein Mediated Membrane Remodeling

    PubMed Central

    Ayton, Gary S.; Voth, Gregory A.

    2009-01-01

    Proteins interacting with membranes can result in substantial membrane deformations and curvatures. This effect is known in its broadest terms as membrane remodeling. This review article will survey current multiscale simulation methodologies that have been employed to examine protein-mediated membrane remodeling. PMID:19922811

  1. Phytochrome Induces Rapid PIF5 Phosphorylation and Degradation in Response to Red-Light Activation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The phytochrome (phy) family of sensory photoreceptors (phyA–phyE in Arabidopsis thaliana) induces changes in target-gene expression upon light-induced translocation to the nucleus, where certain members interact with selected members of the constitutively nuclear basic helix-loop-helix transcriptio...

  2. Fruit development: new directions for an old pathway.

    PubMed

    Moran, Colin N; Halliday, Karen J

    2010-12-21

    A recent study investigating the molecular mechanisms of seed pod shattering has shown that the basic helix-loop-helix (bHLH) proteins INDEHISCENT and ALCATRAZ appear to regulate fruit patterning through gibberellic acid (GA)-DELLA signalling, revealing a central role for bHLH family members in GA response specificity. PMID:21172630

  3. Functional profiling identifies genes involved in organ specific branches of the PIF3 regulatory network in Arabidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The phytochrome (phy)-interacting basic helix-loop-helix transcription factors (PIFs) constitutively sustain the etiolated state of dark-germinated seedlings by actively repressing deetiolation in darkness. This action is rapidly reversed upon light exposure by phy-induced proteolytic degradation of...

  4. Mechanics of Protein-Mediated DNA Looping

    NASA Astrophysics Data System (ADS)

    Meiners, Jens-Christian

    2009-03-01

    The formation of looped DNA-protein complexes in which a protein or protein assembly binds to multiple distant operator sites on the DNA is a common feature for many regulatory schemes on the transcriptional level. In a living cell, a multitude of mechanical forces and constraints act on these complexes, and it is imperative to understand their effects on biological function. For this aim, we study the lactose repressor as a model system for protein-mediated DNA looping in single-molecule experiments. Using a novel axial constant-force optical trapping scheme that allows us to manipulate sub-micron DNA fragments with well-controlled forces down to the 10 fN range, we show that mechanical tension in the substrate DNA of hundred femtonewton is sufficient to disrupt the loop formation process, which suggests that such mechanical tension may provide a mechanical pathway to controlling gene expression in vivo. From the force sensitivity of the loop formation process, we can also infer the topology of the looped complex; in our case an antiparallel conformation. In addition, we will present new tethered-particle microscopy data that shows lifetimes of the looped complexes that are two to three orders of magnitude shorter than those measured in biochemical competition assays and discuss possible interpretations, including the suggestion that operator binding of the lactose repressor tetramer leads to a destabilization of the dimer-dimer interface and that thus the loop breakdown process is mostly a dissociation of the tetramer into two dimers, instead, as widely assumed, an unbinding of the tetramer from the DNA.

  5. Differences between MyoD DNA binding and activation site requirements revealed by functional random sequence selection.

    PubMed Central

    Huang, J; Blackwell, T K; Kedes, L; Weintraub, H

    1996-01-01

    A method has been developed for selecting functional enhancer/promoter sites from random DNA sequences in higher eukaryotic cells. Of sequences that were thus selected for transcriptional activation by the muscle-specific basic helix-loop-helix protein MyoD, only a subset are similar to the preferred in vitro binding consensus, and in the same promoter context an optimal in vitro binding site was inactive. Other sequences with full transcriptional activity instead exhibit sequence preferences that, remarkably, are generally either identical or very similar to those found in naturally occurring muscle-specific promoters. This first systematic examination of the relation between DNA binding and transcriptional activation by basic helix-loop-helix proteins indicates that binding per se is necessary but not sufficient for transcriptional activation by MyoD and implies a requirement for other DNA sequence-dependent interactions or conformations at its binding site. PMID:8668207

  6. Differential transcriptional regulation by mouse single-minded 2s.

    PubMed

    Metz, Richard P; Kwak, Hyeong-Il; Gustafson, Tanya; Laffin, Brian; Porter, Weston W

    2006-04-21

    Single-minded 1 and 2 are unique members of the basic helix-loop-helix Per-Arnt-Sim family as they are transcriptional repressors. Here we report the identification and transcriptional characterization of mouse Sim2s, a splice variant of Sim2, which is missing the carboxyl Pro/Ala-rich repressive domain. Sim2s is expressed at high levels in kidney and skeletal muscle; however, the ratio of Sim2 to Sim2s mRNA differs between these tissues. Similar to full-length Sim2, Sim2s interacts with Arnt and to a lesser extent, Arnt2. The effects of Sim2s on transcriptional regulation through hypoxia, dioxin, and central midline response elements are different than that of full-length Sim2. Specifically, Sim2s exerts a less repressive effect on hypoxia-induced gene expression than full-length Sim2, but is just as effective as Sim2 at repressing TCDD-induced gene expression from a dioxin response element. Interestingly, Sim2s bind to and activates expression from a central midline response element-controlled reporter through an Arnt transactivation domain-dependent mechanism. The differences in expression pattern, protein interactions, and transcriptional activities between Sim2 and Sim2s may reflect differential roles each isoform plays during development or in tissue-specific effects on other protein-mediated pathways. PMID:16484282

  7. ABC-F Proteins Mediate Antibiotic Resistance through Ribosomal Protection

    PubMed Central

    Sharkey, Liam K. R.; Edwards, Thomas A.

    2016-01-01

    ABSTRACT Members of the ABC-F subfamily of ATP-binding cassette proteins mediate resistance to a broad array of clinically important antibiotic classes that target the ribosome of Gram-positive pathogens. The mechanism by which these proteins act has been a subject of long-standing controversy, with two competing hypotheses each having gained considerable support: antibiotic efflux versus ribosomal protection. Here, we report on studies employing a combination of bacteriological and biochemical techniques to unravel the mechanism of resistance of these proteins, and provide several lines of evidence that together offer clear support to the ribosomal protection hypothesis. Of particular note, we show that addition of purified ABC-F proteins to an in vitro translation assay prompts dose-dependent rescue of translation, and demonstrate that such proteins are capable of displacing antibiotic from the ribosome in vitro. To our knowledge, these experiments constitute the first direct evidence that ABC-F proteins mediate antibiotic resistance through ribosomal protection. PMID:27006457

  8. Armet is an effector protein mediating aphid-plant interactions.

    PubMed

    Wang, Wei; Dai, Huaien; Zhang, Yi; Chandrasekar, Raman; Luo, Lan; Hiromasa, Yasuaki; Sheng, Changzhong; Peng, Gongxin; Chen, Shaoliang; Tomich, John M; Reese, John; Edwards, Owain; Kang, Le; Reeck, Gerald; Cui, Feng

    2015-05-01

    Aphid saliva is predicted to contain proteins that modulate plant defenses and facilitate feeding. Armet is a well-characterized bifunctional protein in mammalian systems. Here we report a new role of Armet, namely as an effector protein in the pea aphid, Acyrthosiphon pisum. Pea aphid Armet's physical and chemical properties and its intracellular role are comparable to those reported for mammalian Armets. Uniquely, we detected Armet in aphid watery saliva and in the phloem sap of fava beans fed on by aphids. Armet's transcript level is several times higher in the salivary gland when aphids feed on bean plants than when they feed on an artificial diet. Knockdown of the Armet transcript by RNA interference disturbs aphid feeding behavior on fava beans measured by the electrical penetration graph technique and leads to a shortened life span. Inoculation of pea aphid Armet protein into tobacco leaves induced a transcriptional response that included pathogen-responsive genes. The data suggest that Armet is an effector protein mediating aphid-plant interactions. PMID:25678626

  9. Prostacyclin-induced hyperthermia - Implication of a protein mediator

    NASA Technical Reports Server (NTRS)

    Kandasamy, S. B.; Williams, B. A.

    1982-01-01

    The mechanism of the prostacyclin-linked hyperthermia is studied in rabbits. Results show that intracerebroventricular administration of prostacyclin (PGI2) induces dose-related hyperthermia at room temperature (21 C), as well as at low (4 C) and high (30 C) ambient temperatures. It is found that this PGI2-induced hyperthermia is not mediated by its stable metabolite 6-keto prostaglandin F-1(alpha). Only one of the three anion transport systems, the liver transport system, appears to be important to the central inactivation of pyrogen, prostaglandin E2, and PGI2. Phenoxybenzamine and pimozide have no thermolytic effect on PGI2-induced hyperthermia, while PGI2 still induces hyperthermia after norepinephrine (NE) and dopamine levels are depleted by 6-hydroxydopamine. Indomethacin and SC-19220 (a PG antagonist) do not antagonize PGI2 induced hyperthermia, while theophylline does not accentuate the PGI2-induced hyperthermia. However, the hyperthermic response to PGI2 is attenuated by central administration of the protein synthesis inhibitor, anisomycin. It is concluded that PGI2-induced hyperthermia is not induced by NE, dopamine, or cyclic AMP, but rather that a protein mediator is implicated in the induction of fever by PG12.

  10. ATG proteins mediate efferocytosis and suppress inflammation in mammary involution

    PubMed Central

    Teplova, Irina; Lozy, Fred; Price, Sandy; Singh, Sukhwinder; Barnard, Nicola; Cardiff, Robert D.; Birge, Raymond B.; Karantza, Vassiliki

    2013-01-01

    Involution is the process of post-lactational mammary gland regression to quiescence and it involves secretory epithelial cell death, stroma remodeling and gland repopulation by adipocytes. Though reportedly accompanying apoptosis, the role of autophagy in involution has not yet been determined. We now report that autophagy-related (ATG) proteins mediate dead cell clearance and suppress inflammation during mammary involution. In vivo, Becn1+/− and Atg7-deficient mammary epithelial cells (MECs) produced ‘competent’ apoptotic bodies, but were defective phagocytes in association with reduced expression of the MERTK and ITGB5 receptors, thus pointing to defective apoptotic body engulfment. Atg-deficient tissues exhibited higher levels of involution-associated inflammation, which could be indicative of a tumor-modulating microenvironment, and developed ductal ectasia, a manifestation of deregulated post-involution gland remodeling. In vitro, ATG (BECN1 or ATG7) knockdown compromised MEC-mediated apoptotic body clearance in association with decreased RAC1 activation, thus confirming that, in addition to the defective phagocytic processing reported by other studies, ATG protein defects also impair dead cell engulfment.   Using two different mouse models with mammary gland-associated Atg deficiencies, our studies shed light on the essential role of ATG proteins in MEC-mediated efferocytosis during mammary involution and provide novel insights into this important developmental process. This work also raises the possibility that a regulatory feedback loop exists, by which the efficacy of phagocytic cargo processing in turn regulates the rate of engulfment and ultimately determines the kinetics of phagocytosis and dead cell clearance. PMID:23380905

  11. The “Sharp” blade against HIF-mediated metastasis

    PubMed Central

    Amelio, Ivano; Melino, Gerry

    2012-01-01

    Hypoxia-inducible factors (HIFs) control cellular adaptation to oxygen deprivation. Cancer cells engage HIFs to sustain their growth in adverse conditions, thus promoting a cellular reprograming that includes metabolism, proliferation, survival and mobility. HIFs overexpression in human cancer biopsies correlates with high metastasis and mortality. A recent report has elucidated a novel mechanism for HIFs regulation in triple-negative breast cancer. Specifically, the basic helix-loop-helix (bHLH), Sharp-1, serves HIF1α to the proteasome and promotes its O2-indendpendet degradation, counteracting HIF-mediated metastasis. These findings shed light on how HIFs are manipulated during cancer pathogenesis. PMID:23187809

  12. Gibberellins control fruit patterning in Arabidopsis thaliana.

    PubMed

    Arnaud, Nicolas; Girin, Thomas; Sorefan, Karim; Fuentes, Sara; Wood, Thomas A; Lawrenson, Tom; Sablowski, Robert; Østergaard, Lars

    2010-10-01

    The Arabidopsis basic helix-loop-helix (bHLH) proteins INDEHISCENT (IND) and ALCATRAZ (ALC) specify tissues required for fruit opening that have major roles in seed dispersal and plant domestication. Here, we show that synthesis of the phytohormone gibberellin is a direct and necessary target of IND, and that ALC interacts directly with DELLA repressors, which antagonize ALC function but are destabilized by gibberellin. Thus, the gibberellin/DELLA pathway has a key role in patterning the Arabidopsis fruit, and the interaction between DELLA and bHLH proteins, previously shown to connect gibberellin and light responses, is a versatile regulatory module also used in tissue patterning. PMID:20889713

  13. Targeting ID2 expression triggers a more differentiated phenotype and reduces aggressiveness in human salivary gland cancer cells.

    PubMed

    Sumida, Tomoki; Ishikawa, Akiko; Nakano, Hiroyuki; Yamada, Tomohiro; Mori, Yoshihide; Desprez, Pierre-Yves

    2016-08-01

    Inhibitors of DNA-binding (ID) proteins are negative regulators of basic helix-loop-helix transcription factors and generally stimulate cell proliferation and inhibit differentiation. We previously determined that ID1 was highly expressed in aggressive salivary gland cancer (SGC) cells in culture. Here, we show that ID2 is also expressed in aggressive SGC cells. ID2 knockdown triggers important changes in cell behavior, that is, it significantly reduces the expression of N-cadherin, vimentin and Snail, induces E-cadherin expression and leads to a more differentiated phenotype exemplified by changes in cell shape. Moreover, ID2 knockdown almost completely suppresses invasion and the expression of matrix metalloproteinase 9. In conclusion, ID2 expression maintains an aggressive phenotype in SGC cells, and ID2 repression triggers a reduction in cell aggressiveness. ID2 therefore represents a potential therapeutic target during SGC progression. ID proteins are negative regulators of basic helix-loop-helix transcription factors and generally stimulate cell proliferation and inhibit differentiation. ID2 knockdown triggers important changes in cell behavior, that is, it significantly reduces the expression of N-cadherin, vimentin and Snail, induces E-cadherin expression and leads to a more differentiated phenotype exemplified by changes in cell shape. ID2 therefore represents a potential therapeutic target during SGC progression. PMID:27364596

  14. Experimental determination of the evolvability of a transcription factor.

    PubMed

    Maerkl, Sebastian J; Quake, Stephen R

    2009-11-01

    Sequence-specific binding of a transcription factor to DNA is the central event in any transcriptional regulatory network. However, relatively little is known about the evolutionary plasticity of transcription factors. For example, the exact functional consequence of an amino acid substitution on the DNA-binding specificity of most transcription factors is currently not predictable. Furthermore, although the major structural families of transcription factors have been identified, the detailed DNA-binding repertoires within most families have not been characterized. We studied the sequence recognition code and evolvability of the basic helix-loop-helix transcription factor family by creating all possible 95 single-point mutations of five DNA-contacting residues of Max, a human helix-loop-helix transcription factor and measured the detailed DNA-binding repertoire of each mutant. Our results show that the sequence-specific repertoire of Max accessible through single-point mutations is extremely limited, and we are able to predict 92% of the naturally occurring diversity at these positions. All naturally occurring basic regions were also found to be accessible through functional intermediates. Finally, we observed a set of amino acids that are functional in vitro but are not found to be used naturally, indicating that functionality alone is not sufficient for selection. PMID:19841254

  15. A juvenile hormone transcription factor Bmdimm-fibroin H chain pathway is involved in the synthesis of silk protein in silkworm, Bombyx mori.

    PubMed

    Zhao, Xiao-Ming; Liu, Chun; Jiang, Li-Jun; Li, Qiong-Yan; Zhou, Meng-Ting; Cheng, Ting-Cai; Mita, Kazuei; Xia, Qing-You

    2015-01-01

    The genes responsible for silk biosynthesis are switched on and off at particular times in the silk glands of Bombyx mori. This switch appears to be under the control of endogenous and exogenous hormones. However, the molecular mechanisms by which silk protein synthesis is regulated by the juvenile hormone (JH) are largely unknown. Here, we report a basic helix-loop-helix transcription factor, Bmdimm, its silk gland-specific expression, and its direct involvement in the regulation of fibroin H-chain (fib-H) by binding to an E-box (CAAATG) element of the fib-H gene promoter. Far-Western blots, enzyme-linked immunosorbent assays, and co-immunoprecipitation assays revealed that Bmdimm protein interacted with another basic helix-loop-helix transcription factor, Bmsage. Immunostaining revealed that Bmdimm and Bmsage proteins are co-localized in nuclei. Bmdimm expression was induced in larval silk glands in vivo, in silk glands cultured in vitro, and in B. mori cell lines after treatment with a JH analog. The JH effect on Bmdimm was mediated by the JH-Met-Kr-h1 signaling pathway, and Bmdimm expression did not respond to JH by RNA interference with double-stranded BmKr-h1 RNA. These data suggest that the JH regulatory pathway, the transcription factor Bmdimm, and the targeted fib-H gene contribute to the synthesis of fibroin H-chain protein in B. mori. PMID:25371208

  16. SPATULA, a gene that controls development of carpel margin tissues in Arabidopsis, encodes a bHLH protein.

    PubMed

    Heisler, M G; Atkinson, A; Bylstra, Y H; Walsh, R; Smyth, D R

    2001-04-01

    Studies involving mutants of the gene SPATULA indicate that it promotes the growth of carpel margins and of pollen tract tissues derived from them. We show that it encodes a new member of the basic-helix-loop-helix family of transcription factors. SPATULA is expressed in marginal and pollen tract tissues throughout their development confirming its role in regulating their growth. It is also expressed in many other tissues where it may act redundantly to control growth, including the peripheral zone of the shoot apical meristem, and specific tissues within leaves, petals, stamens and roots. Expression in the stomium, funiculus and valve dehiscence zone indicates an additional role in abscission. SPATULA expression does not require the function of the other carpel development genes CRABS CLAW and AGAMOUS, although its expression is repressed in first whorl organs by the A function gene APETALA2. Further, we have shown that disruptions to gynoecial pattern formation seen in ettin mutants can largely be attributed to ectopic SPATULA action. ETTIN's role seems to be to negatively regulate SPATULA expression in abaxial regions of the developing gynoecium. SPATULA is the first basic-helix-loop-helix gene in plants known to play a role in floral organogenesis. PMID:11245574

  17. The MYB182 Protein Down-Regulates Proanthocyanidin and Anthocyanin Biosynthesis in Poplar by Repressing Both Structural and Regulatory Flavonoid Genes1[OPEN

    PubMed Central

    Yoshida, Kazuko; Ma, Dawei; Constabel, C. Peter

    2015-01-01

    Trees in the genus Populus (poplar) contain phenolic secondary metabolites including the proanthocyanidins (PAs), which help to adapt these widespread trees to diverse environments. The transcriptional activation of PA biosynthesis in response to herbivory and ultraviolet light stress has been documented in poplar leaves, and a regulator of this process, the R2R3-MYB transcription factor MYB134, has been identified. MYB134-overexpressing transgenic plants show a strong high-PA phenotype. Analysis of these transgenic plants suggested the involvement of additional MYB transcription factors, including repressor-like MYB factors. Here, MYB182, a subgroup 4 MYB factor, was found to act as a negative regulator of the flavonoid pathway. Overexpression of MYB182 in hairy root culture and whole poplar plants led to reduced PA and anthocyanin levels as well as a reduction in the expression of key flavonoid genes. Similarly, a reduced accumulation of transcripts of a MYB PA activator and a basic helix-loop-helix cofactor was observed in MYB182-overexpressing hairy roots. Transient promoter activation assays in poplar cell culture demonstrated that MYB182 can disrupt transcriptional activation by MYB134 and that the basic helix-loop-helix-binding motif of MYB182 was essential for repression. Microarray analysis of transgenic plants demonstrated that down-regulated targets of MYB182 also include shikimate pathway genes. This work shows that MYB182 plays an important role in the fine-tuning of MYB134-mediated flavonoid metabolism. PMID:25624398

  18. Rhizobium nod factor signaling. Evidence for a g protein-mediated transduction mechanism

    PubMed Central

    Pingret, JL; Journet, EP; Barker, DG

    1998-01-01

    Rhizobium nodulation (Nod) factors are lipochitooligosaccharide signals that elicit key symbiotic developmental responses in the host legume root. In this study, we have investigated Nod factor signal transduction in the Medicago root epidermis by using a pharmacological approach in conjunction with transgenic plants expressing the Nod factor-responsive reporter construct pMtENOD12-GUS. Evidence for the participation of heterotrimeric G proteins in Nod factor signaling has come from three complementary observations: (1) the amphiphilic peptides mastoparan and Mas7, known G protein agonists, are able to mimic Nod factor-induced epidermal MtENOD12 expression; (2) growth of plants in nodulation-inhibiting conditions (10 mM NH4NO3) leads to a dramatic reduction in both Nod factor- and mastoparan-elicited gene expression; and (3) bacterial pertussis toxin, a well-characterized G protein antagonist, blocks the activities of both the Nod factor and mastoparan. In addition, we have found that antagonists that interfere with phospholipase C activity (neomycin and U73122) and Ca2+ influx/release (EGTA, La3+, and ruthenium red) block Nod factor/mastoparan activity. Taken together, these results are consistent with a Nod factor signal transduction mechanism involving G protein mediation coupled to the activation of both phosphoinositide and Ca2+ second messenger pathways. PMID:9596628

  19. Refractive-Index-Based Screening of Membrane-Protein-Mediated Transfer across Biological Membranes

    PubMed Central

    Brändén, Magnus; Tabaei, Seyed R.; Fischer, Gerhard; Neutze, Richard; Höök, Fredrik

    2010-01-01

    Abstract Numerous membrane-transport proteins are major drug targets, and therefore a key ingredient in pharmaceutical development is the availability of reliable, efficient tools for membrane transport characterization and inhibition. Here, we present the use of evanescent-wave sensing for screening of membrane-protein-mediated transport across lipid bilayer membranes. This method is based on a direct recording of the temporal variations in the refractive index that occur upon a transfer-dependent change in the solute concentration inside liposomes associated to a surface plasmon resonance (SPR) active sensor surface. The applicability of the method is demonstrated by a functional study of the aquaglyceroporin PfAQP from the malaria parasite Plasmodium falciparum. Assays of the temperature dependence of facilitated diffusion of sugar alcohols on a single set of PfAQP-reconstituted liposomes reveal that the activation energies for facilitated diffusion of xylitol and sorbitol are the same as that previously measured for glycerol transport in the aquaglyceroporin of Escherichia coli (5 kcal/mole). These findings indicate that the aquaglyceroporin selectivity filter does not discriminate sugar alcohols based on their length, and that the extra energy cost of dehydration of larger sugar alcohols, upon entering the pore, is compensated for by additional hydrogen-bond interactions within the aquaglyceroporin pore. PMID:20655840

  20. RNA-induced silencing attenuates G protein-mediated calcium signals.

    PubMed

    Philip, Finly; Sahu, Shriya; Golebiewska, Urszula; Scarlata, Suzanne

    2016-05-01

    Phospholipase Cβ (PLCβ) is activated by G protein subunits in response to environmental stimuli to increase intracellular calcium. In cells, a significant portion of PLCβ is cytosolic, where it binds a protein complex required for efficient RNA-induced silencing called C3PO (component 3 promoter of RISC). Binding between C3PO and PLCβ raises the possibility that RNA silencing activity can affect the ability of PLCβ to mediate calcium signals. By use of human and rat neuronal cell lines (SK-N-SH and PC12), we show that overexpression of one of the main components of C3PO diminishes Ca(2+) release in response to Gαq/PLCβ stimulation by 30 to 40%. In untransfected SK-N-SH or PC12 cells, the introduction of siRNA(GAPDH) [small interfering RNA(glyceraldehyde 3-phosphate dehydrogenase)] reduces PLCβ-mediated calcium signals by ∼30%, but addition of siRNA(Hsp90) (heat shock protein 90) had little effect. Fluorescence imaging studies suggest an increase in PLCβ-C3PO association in cells treated with siRNA(GAPDH) but not siRNA(Hsp90). Taken together, our studies raise the possibility that Ca(2+) responses to extracellular stimuli can be modulated by components of the RNA silencing machinery.-Philip, F., Sahu, S., Golebiewska, U., Scarlata, S. RNA-induced silencing attenuates G protein-mediated calcium signals. PMID:26862135

  1. Effect of Reactor Turbulence on the Binding-Protein-Mediated Aspartate Transport System in Thin Wastewater Biofilms

    PubMed Central

    Eighmy, T. Taylor; Bishop, P. L.

    1985-01-01

    This research documents an effect of reactor turbulence on the ability of gram-negative wastewater biofilm bacteria to actively transport l-aspartate via a binding-protein-mediated transport system. Biofilms which were not preadapted to turbulence and which possessed two separate and distinct aspartate transport systems (systems 1 and 2) were subjected to a turbulent flow condition in a hydrodynamically defined closed-loop reactor system. A shear stress treatment of 3.1 N · m−2 for 10 min at a turbulent Reynolds number (Re = 11,297) inactivated the low-affinity, high-capacity binding-protein-mediated transport system (system 2) and resolved the high-affinity, low-capacity membrane-bound proton symport system (system 1). The Kt and Vmax values for the resolved system were statistically similar to Kt and Vmax values for system 1 when system 2 was inactivated either by osmotic shock or arsenate, two treatments which are known to inactivate binding-protein-mediated transport systems. We hypothesize that shear stress disrupts system 2 by deforming the outer membranes of the firmly adhered gram-negative bacteria. PMID:16346830

  2. Basic Warehousing.

    ERIC Educational Resources Information Center

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on basic warehousing is designed to provide Marines with Military Occupation Speciality 3051 in the rank of private through corporal with instruction in those basic principles, methods, and procedures that can be applied to any warehousing or storage…

  3. BASIC Programming.

    ERIC Educational Resources Information Center

    Jennings, Carol Ann

    Designed for use by both secondary- and postsecondary-level business teachers, this curriculum guide consists of 10 units of instructional materials dealing with Beginners All-Purpose Symbol Instruction Code (BASIC) programing. Topics of the individual lessons are numbering BASIC programs and using the PRINT, END, and REM statements; system…

  4. French Basic Course: Basic Situations.

    ERIC Educational Resources Information Center

    Defense Language Inst., Monterey, CA.

    This volume of the French Basic Course contains ten situations from daily life, each divided into five sub-situations. The material for each situation consists of cartoons and lists of selected words. The purpose of the volume is to provide a vehicle for reviewing the grammar and vocabulary of lessons 1-85 of the Basic Course and adding new words…

  5. The Basics

    ERIC Educational Resources Information Center

    Indrisano, Roselmina; And Others

    1976-01-01

    These articles are presented as an aide in teaching basic subjects. This issue examines reading diagnosis, food preservation, prime numbers, electromagnets, acting out in language arts, self-directed spelling activities, and resources for environmental education. (Editor/RK)

  6. Cancer Basics

    MedlinePlus

    ... Cancer? Breast Cancer Colon/Rectum Cancer Lung Cancer Prostate Cancer Skin Cancer Show All Cancer Types News and Features Cancer Glossary ACS Bookstore Cancer Information Cancer Basics Cancer Prevention & Detection Signs & Symptoms of Cancer Treatments & Side Effects ...

  7. Basic Finance

    NASA Technical Reports Server (NTRS)

    Vittek, J. F.

    1972-01-01

    A discussion of the basic measures of corporate financial strength, and the sources of the information is reported. Considered are: balance sheet, income statement, funds and cash flow, and financial ratios.

  8. Schizophrenia Basics

    MedlinePlus

    ... I know with schizophrenia? For More Information Share Schizophrenia Basics Download PDF Download ePub Order a free hardcopy What is schizophrenia? Schizophrenia is a serious mental disorder that affects ...

  9. Fluoridation Basics

    MedlinePlus

    ... Water Fluoridation Journal Articles for Community Water Fluoridation Water Fluoridation Basics Recommend on Facebook Tweet Share Compartir ... because of tooth decay. History of Fluoride in Water In the 1930s, scientists examined the relationship between ...

  10. Id transcriptional regulators in adipogenesis and adipose tissue metabolism

    PubMed Central

    Patil, Mallikarjun; Sharma, Bal Krishan; Satyanarayana, Ande

    2014-01-01

    Id proteins (Id1-Id4) are helix-loop-helix (HLH) transcriptional regulators that lack a basic DNA binding domain. They act as negative regulators of basic helixloop-helix (bHLH) transcription factors by forming heterodimers and inhibit their DNA binding and transcriptional activity. Id proteins are implicated in the regulation of various cellular mechanisms such as cell proliferation, cellular differentiation, cell fate determination, angiogenesis and tumorigenesis. A handful of recent studies also disclosed that Id proteins have critical functions in adipocyte differentiation and adipose tissue metabolism. Here, we reviewed the progress made thus far in understanding the specific functions of Id proteins in adipose tissue differentiation and metabolism. In addition to reviewing the known mechanisms of action, we also discuss possible additional mechanisms in which Id proteins might participate in regulating adipogenic and metabolic pathways. PMID:24896358

  11. Lipid transfer protein-mediated resistance to a trichothecene mycotoxin – Novel players in FHB resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lipid transfer proteins are a class of basic cysteine rich proteins characterized by an eight cysteine motif backbone with intrinsic antimicrobial activities against bacterial and fungal pathogens. Previously, we identified two type IV nonspecific lipid transfer protein (nsLTP) genes (LTP4.4 and LTP...

  12. DOS basics

    SciTech Connect

    O`Connor, P.

    1994-09-01

    DOS is an acronym for Disk Operating System. It is actually a set of programs that allows you to control your personal computer. DOS offers the capabilities to create and manage files; organize and maintain information placed on disks; use application programs such as WordPerfect, Lotus 123, Excel, Windows, etc. In addition, DOS provides the basic utilities needed to copy files from one area to another, delete files and list files. The latest version of DOS also offers more advanced features that include hard disk compression and memory management. Basic DOS commands are discussed.

  13. Basic Skills.

    ERIC Educational Resources Information Center

    Luparelli, Augustus N.; And Others

    1981-01-01

    These four articles focus on developing basic reading, science, and job search skills: "Reading Program for Vocational Classes" by Augustus Luparelli; "Why Teach Employability Skills?" by Larry Siefferman; "Improving Vocabulary and Reading Skills" by Edythe Conway; and "Science in Everyday Life" by Virginia Eleazer and George Carney. (SK)

  14. Body Basics

    MedlinePlus

    ... more about how the body works, what basic human anatomy is, and what happens when parts of the body don't function properly. Blood Bones, Muscles, and Joints Brain and Nervous System Digestive System Endocrine System Eyes Female Reproductive System ...

  15. Basic Backwardness.

    ERIC Educational Resources Information Center

    Weingartner, Charles

    This paper argues that the "back to basics" movement is regressive and that regression is the characteristic mode of fear-ridden personalities. It is argued that many people in American society today have lost their ability to laugh and do not have the sense of humor which is crucial to a healthy mental state. Such topics as necrophilia, mental…

  16. Armchair BASIC.

    ERIC Educational Resources Information Center

    Fox, Annie; Fox, David

    1983-01-01

    A first lesson in learning the computer programing language BASIC, this article explains how to give instructions to the computer; the commands PRINT, NEW, LIST, and RUN; and how to do simple line editing. There is a short quiz at the end. (EAO)

  17. Ethanol Basics

    SciTech Connect

    2015-01-30

    Ethanol is a widely-used, domestically-produced renewable fuel made from corn and other plant materials. More than 96% of gasoline sold in the United States contains ethanol. Learn more about this alternative fuel in the Ethanol Basics Fact Sheet, produced by the U.S. Department of Energy's Clean Cities program.

  18. Basic Science.

    ERIC Educational Resources Information Center

    Mercer County Community Coll., Trenton, NJ.

    Instructional materials are provided for a course that covers basic concepts of physics and chemistry. Designed for use in a workplace literacy project developed by Mercer County Community College (New Jersey) and its partners, the course describes applications of these concepts to real-life situations, with an emphasis on applications of…

  19. Basic Horticulture.

    ERIC Educational Resources Information Center

    Geer, Barbra Farabough

    This learning packet contains teaching suggestions and student learning materials for a course in basic horticulture aimed at preparing students for employment in a number of horticulture areas. The packet includes nine sections and twenty instructional units. Following the standard format established for Oklahoma vocational education materials in…

  20. Basic Education.

    ERIC Educational Resources Information Center

    Robinson, Virginia, Ed.

    1984-01-01

    This issue of "Basic Education" is devoted to the arts in education as a concern that should be addressed in a time of new priorities for the curriculum. Five articles and a book review are included. The opening article, "The State of the Arts in Education: Envisioning Active Participation By All" (Virginia Robinson), emphasizes that the study of…

  1. Direct Detection of Transcription Factors in Cotyledons during Seedling Development Using Sensitive Silicon-Substrate Photonic Crystal Protein Arrays1[OPEN

    PubMed Central

    Jones, Sarah I.; Tan, Yafang; Shamimuzzaman, Md; George, Sherine; Cunningham, Brian T.; Vodkin, Lila

    2015-01-01

    Transcription factors control important gene networks, altering the expression of a wide variety of genes, including those of agronomic importance, despite often being expressed at low levels. Detecting transcription factor proteins is difficult, because current high-throughput methods may not be sensitive enough. One-dimensional, silicon-substrate photonic crystal (PC) arrays provide an alternative substrate for printing multiplexed protein microarrays that have greater sensitivity through an increased signal-to-noise ratio of the fluorescent signal compared with performing the same assay upon a traditional aminosilanized glass surface. As a model system to test proof of concept of the silicon-substrate PC arrays to directly detect rare proteins in crude plant extracts, we selected representatives of four different transcription factor families (zinc finger GATA, basic helix-loop-helix, BTF3/NAC [for basic transcription factor of the NAC family], and YABBY) that have increasing transcript levels during the stages of seedling cotyledon development. Antibodies to synthetic peptides representing the transcription factors were printed on both glass slides and silicon-substrate PC slides along with antibodies to abundant cotyledon proteins, seed lectin, and Kunitz trypsin inhibitor. The silicon-substrate PC arrays proved more sensitive than those performed on glass slides, detecting rare proteins that were below background on the glass slides. The zinc finger transcription factor was detected on the PC arrays in crude extracts of all stages of the seedling cotyledons, whereas YABBY seemed to be at the lower limit of their sensitivity. Interestingly, the basic helix-loop-helix and NAC proteins showed developmental profiles consistent with their transcript patterns, indicating proof of concept for detecting these low-abundance proteins in crude extracts. PMID:25635113

  2. Direct detection of transcription factors in cotyledons during seedling development using sensitive silicon-substrate photonic crystal protein arrays.

    PubMed

    Jones, Sarah I; Tan, Yafang; Shamimuzzaman, Md; George, Sherine; Cunningham, Brian T; Vodkin, Lila

    2015-03-01

    Transcription factors control important gene networks, altering the expression of a wide variety of genes, including those of agronomic importance, despite often being expressed at low levels. Detecting transcription factor proteins is difficult, because current high-throughput methods may not be sensitive enough. One-dimensional, silicon-substrate photonic crystal (PC) arrays provide an alternative substrate for printing multiplexed protein microarrays that have greater sensitivity through an increased signal-to-noise ratio of the fluorescent signal compared with performing the same assay upon a traditional aminosilanized glass surface. As a model system to test proof of concept of the silicon-substrate PC arrays to directly detect rare proteins in crude plant extracts, we selected representatives of four different transcription factor families (zinc finger GATA, basic helix-loop-helix, BTF3/NAC [for basic transcription factor of the NAC family], and YABBY) that have increasing transcript levels during the stages of seedling cotyledon development. Antibodies to synthetic peptides representing the transcription factors were printed on both glass slides and silicon-substrate PC slides along with antibodies to abundant cotyledon proteins, seed lectin, and Kunitz trypsin inhibitor. The silicon-substrate PC arrays proved more sensitive than those performed on glass slides, detecting rare proteins that were below background on the glass slides. The zinc finger transcription factor was detected on the PC arrays in crude extracts of all stages of the seedling cotyledons, whereas YABBY seemed to be at the lower limit of their sensitivity. Interestingly, the basic helix-loop-helix and NAC proteins showed developmental profiles consistent with their transcript patterns, indicating proof of concept for detecting these low-abundance proteins in crude extracts. PMID:25635113

  3. New insights into the role of ID proteins in breast cancer metastasis: a MET affair

    PubMed Central

    2014-01-01

    The establishment of lethal metastases depends on the capacity of a small number of cancer cells to regenerate a tumor after entering a target organ. Stankic and colleagues have identified a role for the inhibitor of differentiation protein, ID1, as a critical regulator of breast cancer stem-like properties and metastatic colonization. Under the control of tumor growth factor-beta signaling, ID1 induces mesenchymal-epithelial transition at the metastatic site by antagonizing the activity of the basic helix-loop-helix transcription factor Twist1. This study sheds light on mechanisms that initiate metastatic outgrowth, and strengthens the concept that epithelial-mesenchymal plasticity is crucial at different stages of metastasis. PMID:25927844

  4. Network theory inspired analysis of time-resolved expression data reveals key players guiding P. patens stem cell development.

    PubMed

    Busch, Hauke; Boerries, Melanie; Bao, Jie; Hanke, Sebastian T; Hiss, Manuel; Tiko, Theodhor; Rensing, Stefan A

    2013-01-01

    Transcription factors (TFs) often trigger developmental decisions, yet, their transcripts are often only moderately regulated and thus not easily detected by conventional statistics on expression data. Here we present a method that allows to determine such genes based on trajectory analysis of time-resolved transcriptome data. As a proof of principle, we have analysed apical stem cells of filamentous moss (P. patens) protonemata that develop from leaflets upon their detachment from the plant. By our novel correlation analysis of the post detachment transcriptome kinetics we predict five out of 1,058 TFs to be involved in the signaling leading to the establishment of pluripotency. Among the predicted regulators is the basic helix loop helix TF PpRSL1, which we show to be involved in the establishment of apical stem cells in P. patens. Our methodology is expected to aid analysis of key players of developmental decisions in complex plant and animal systems. PMID:23637751

  5. HEB and E2A function as SMAD/FOXH1 cofactors.

    PubMed

    Yoon, Se-Jin; Wills, Andrea E; Chuong, Edward; Gupta, Rakhi; Baker, Julie C

    2011-08-01

    Nodal signaling, mediated through SMAD transcription factors, is necessary for pluripotency maintenance and endoderm commitment. We identified a new motif, termed SMAD complex-associated (SCA), that is bound by SMAD2/3/4 and FOXH1 in human embryonic stem cells (hESCs) and derived endoderm. We demonstrate that two basic helix-loop-helix (bHLH) proteins-HEB and E2A-bind the SCA motif at regions overlapping SMAD2/3 and FOXH1. Furthermore, we show that HEB and E2A associate with SMAD2/3 and FOXH1, suggesting they form a complex at critical target regions. This association is biologically important, as E2A is critical for mesendoderm specification, gastrulation, and Nodal signal transduction in Xenopus tropicalis embryos. Taken together, E proteins are novel Nodal signaling cofactors that associate with SMAD2/3 and FOXH1 and are necessary for mesendoderm differentiation. PMID:21828274

  6. TCF12 microdeletion in a 72-year-old woman with intellectual disability.

    PubMed

    Piard, Juliette; Rozé, Virginie; Czorny, Alain; Lenoir, Marion; Valduga, Mylène; Fenwick, Aimée L; Wilkie, Andrew O M; Maldergem, Lionel Van

    2015-08-01

    Heterozygous mutations in TCF12 were recently identified as an important cause of craniosynostosis. In the original series, 14% of patients with a mutation in TCF12 had significant developmental delay or learning disability. We report on the first case of TCF12 microdeletion, detected by array-comparative genomic hybridization, in a 72-year-old patient presenting with intellectual deficiency and dysmorphism. Multiplex ligation-dependent probe amplification analysis indicated that exon 19, encoding the functionally important basic helix-loop-helix domain, was included in the deleted segment in addition to exon 20. We postulate that the TCF12 microdeletion is responsible for this patient's intellectual deficiency and facial phenotype. PMID:25871887

  7. The bHLH transcription factor Tcf12 (ME1) mRNA is abundantly expressed in Paneth cells of mouse intestine.

    PubMed

    Tanigawa, Yoko; Yakura, Rieko; Komiya, Tohru

    2007-06-01

    Using a large-scale in situ hybridization screening system, we found that mRNA coding for ME1, a basic helix-loop-helix (bHLH) transcription factor, was abundantly expressed in Paneth cells of adult small intestinal crypts. Other functionally related E-protein mRNAs, ME2, and E2A, however, could not be detected in the cells. ME1 mRNA was first detected in the jejunum and ileum two weeks after birth when the number of Paneth cells starts to increase. ME1 is the first identified bHLH transcription factor expressed in the Paneth cells and may be used as a molecular marker and a key molecule for analyzing transcriptional regulation in the Paneth cell. PMID:17405739

  8. NGF-dependent and tissue-specific transcription of vgf is regulated by a CREB-p300 and bHLH factor interaction.

    PubMed

    Mandolesi, Georgia; Gargano, Silvia; Pennuto, Maria; Illi, Barbara; Molfetta, Rosa; Soucek, Laura; Mosca, Laura; Levi, Andrea; Jucker, Richard; Nasi, Sergio

    2002-01-01

    Neurotrophins support neuronal survival, development, and plasticity through processes requiring gene expression. We studied how vgf target gene transcription is mediated by a critical promoter region containing E-box, CCAAT and cAMP response element (CRE) sites. The p300 acetylase was present in two distinct protein complexes bound to this region. One complex, containing HEB (ubiquitous basic helix-loop-helix (bHLH)), bound the promoter in non-neuronal cells and was involved in repressing vgf expression. Neurotrophin-dependent transcription was mediated by the second complex, specific for neuronal cells, which included CRE binding protein and MASH1 (neuro-specific bHLH), bound the CCAAT motif, and was target of neurotrophin signalling. The interaction, mediated by p300, of different transcription factors may add specificity to the neurotrophin response. PMID:11755530

  9. E proteins in lymphocyte development and lymphoid diseases.

    PubMed

    Belle, Ian; Zhuang, Yuan

    2014-01-01

    As members of the basic helix-loop-helix (bHLH) family of transcription factors, E proteins function in the immune system by directing and maintaining a vast transcriptional network that regulates cell survival, proliferation, differentiation, and function. Proper activity of this network is essential to the functionality of the immune system. Aberrations in E protein expression or function can cause numerous defects, ranging from impaired lymphocyte development and immunodeficiency to aberrant function, cancer, and autoimmunity. Additionally, disruption of inhibitor of DNA-binding (Id) proteins, natural inhibitors of E proteins, can induce additional defects in development and function. Although E proteins have been investigated for several decades, their study continues to yield novel and exciting insights into the workings of the immune system. The goal of this chapter is to discuss the various classical roles of E proteins in lymphocyte development and highlight new and ongoing research into how these roles, if compromised, can lead to disease. PMID:25248476

  10. BHLHB3: a candidate tumor suppressor in lung cancer.

    PubMed

    Falvella, F S; Colombo, F; Spinola, M; Campiglio, M; Pastorino, U; Dragani, T A

    2008-06-12

    BHLHB3 is a basic helix-loop-helix (bHLH) domain-containing protein that acts as a transcriptional repressor. We found that BHLHB3 transcript levels were low in three human lung cancer cell lines and downregulated in human lung adenocarcinomas as compared to normal lung tissue. BHLHB3 gene overexpression inhibited colony formation of A549, NCI-H520 and NCI-H596 lung cancer cells. The reduced colony growth was likely due to inhibition of cell proliferation as suggested by the downregulation of cyclin D1 (CCND1) expression in NCI-H520 cells transfected to overexpress the BHLHB3 gene; no evidence of apoptosis was observed. These results point to the potential role of the BHLHB3 protein as a tumor suppressor for lung cancer. PMID:18223678

  11. Unique CCT repeats mediate transcription of the TWIST1 gene in mesenchymal cell lines

    SciTech Connect

    Ohkuma, Mizue; Funato, Noriko; Higashihori, Norihisa; Murakami, Masanori; Ohyama, Kimie; Nakamura, Masataka . E-mail: naka.gene@cmn.tmd.ac.jp

    2007-01-26

    TWIST1, a basic helix-loop-helix transcription factor, plays critical roles in embryo development, cancer metastasis and mesenchymal progenitor differentiation. Little is known about transcriptional regulation of TWIST1 expression. Here we identified DNA sequences responsible for TWIST1 expression in mesenchymal lineage cell lines. Reporter assays with TWIST1 promoter mutants defined the -102 to -74 sequences that are essential for TWIST1 expression in human and mouse mesenchymal cell lines. Tandem repeats of CCT, but not putative CREB and NF-{kappa}B sites in the sequences substantially supported activity of the TWIST1 promoter. Electrophoretic mobility shift assay demonstrated that the DNA sequences with the CCT repeats formed complexes with nuclear factors, containing, at least, Sp1 and Sp3. These results suggest critical implication of the CCT repeats in association with Sp1 and Sp3 factors in sustaining expression of the TWIST1 gene in mesenchymal cells.

  12. The Transcriptional Coregulator LEUNIG_HOMOLOG Inhibits Light-Dependent Seed Germination in Arabidopsis.

    PubMed

    Lee, Nayoung; Park, Jeongmoo; Kim, Keunhwa; Choi, Giltsu

    2015-08-01

    PHYTOCHROME-INTERACTING FACTOR1 (PIF1) is a basic helix-loop-helix transcription factor that inhibits light-dependent seed germination in Arabidopsis thaliana. However, it remains unclear whether PIF1 requires other factors to regulate its direct targets. Here, we demonstrate that LEUNIG_HOMOLOG (LUH), a Groucho family transcriptional corepressor, binds to PIF1 and coregulates its targets. Not only are the transcriptional profiles of the luh and pif1 mutants remarkably similar, more than 80% of the seeds of both genotypes germinate in the dark. We show by chromatin immunoprecipitation that LUH binds a subset of PIF1 targets in a partially PIF1-dependent manner. Unexpectedly, we found LUH binds and coregulates not only PIF1-activated targets but also PIF1-repressed targets. Together, our results indicate LUH functions with PIF1 as a transcriptional coregulator to inhibit seed germination. PMID:26276832

  13. Molecular mechanisms of epithelial–mesenchymal transition

    PubMed Central

    Lamouille, Samy; Xu, Jian; Derynck, Rik

    2014-01-01

    The transdifferentiation of epithelial cells into motile mesenchymal cells, a process known as epithelial–mesenchymal transition (EMT), is integral in development, wound healing and stem cell behaviour, and contributes pathologically to fibrosis and cancer progression. This switch in cell differentiation and behaviour is mediated by key transcription factors, including SNAIL, zinc-finger E-box-binding (ZEB) and basic helix-loop-helix transcription factors, the functions of which are finely regulated at the transcriptional, translational and post-translational levels. The reprogramming of gene expression during EMT, as well as non-transcriptional changes, are initiated and controlled by signalling pathways that respond to extracellular cues. Among these, transforming growth factor-β (TGFβ) family signalling has a predominant role; however, the convergence of signalling pathways is essential for EMT. PMID:24556840

  14. Phenolic compounds from the bark of Oroxylum indicum activate the Ngn2 promoter.

    PubMed

    Fuentes, Rolly G; Arai, Midori A; Sadhu, Samir K; Ahmed, Firoj; Ishibashi, Masami

    2015-10-01

    A reporter gene assay that detects neurogenin 2 (Ngn2) promoter activity was utilized to identify compounds that induce neuronal differentiation. Ngn2 is a basic helix-loop-helix transcription factor that activates transcription of pro-neural genes. Using this assay system and an activity-guided approach, seven phenolic compounds were isolated from the methanol extract of Oroxylum indicum: 1 oroxylin A, 2 chrysin, 3 hispidulin, 4 baicalein, 5 apigenin, 6 baicalin, and 7 isoverbascoside. Compounds 1 and 2 induced an estimated 2.7-fold increase in Ngn2 promoter activity, whereas 3 increased the activity by 2.5-fold. Furthermore, 1 and 2 enhanced neuronal differentiation of C17.2 cells, which are multipotent stem cells. PMID:26014045

  15. Flavonoids: biosynthesis, biological functions, and biotechnological applications

    PubMed Central

    Falcone Ferreyra, María L.; Rius, Sebastián P.; Casati, Paula

    2012-01-01

    Flavonoids are widely distributed secondary metabolites with different metabolic functions in plants. The elucidation of the biosynthetic pathways, as well as their regulation by MYB, basic helix-loop-helix (bHLH), and WD40-type transcription factors, has allowed metabolic engineering of plants through the manipulation of the different final products with valuable applications. The present review describes the regulation of flavonoid biosynthesis, as well as the biological functions of flavonoids in plants, such as in defense against UV-B radiation and pathogen infection, nodulation, and pollen fertility. In addition, we discuss different strategies and achievements through the genetic engineering of flavonoid biosynthesis with implication in the industry and the combinatorial biosynthesis in microorganisms by the reconstruction of the pathway to obtain high amounts of specific compounds. PMID:23060891

  16. Transcriptomic analyses of Hand2 transgenic embryos.

    PubMed

    Funato, Noriko; Kokubo, Hiroki; Saga, Yumiko

    2016-09-01

    In this article, we further provide the data generated for the previously published research article "Specification of jaw identity by the Hand2 transcription factor." To better understand the downstream genes of the basic helix-loop-helix transcription factor Hand2, we generated double-transgenic mice (Hand2 (NC) ) by intercrossing CAG-floxed CAT-Hand2 mice with Wnt1-Cre mice for conditional activation of Hand2 expression in the neural crest. Altered expression of Hand2 induces transformation of the upper jaw to the lower jaw in Hand2 (NC) mutant mice. This data article provides Tables detailing the differentially expressed genes between wild-type and Hand2 (NC) mutant embryos. The raw array data of our transcriptomes as generated using Affymetrix microarrays are available on the NCBI Gene Expression Omnibus (GEO) browser (Reference number GSE75805). PMID:27408813

  17. A novel SREBP-1 splice variant: tissue abundance and transactivation potency.

    PubMed

    Felder, Thomas Klaus; Klein, Kerstin; Patsch, Wolfgang; Oberkofler, Hannes

    2005-10-15

    Sterol regulatory element binding proteins (SREBPs) belong to the family of basic helix-loop-helix-leucine zipper transcription factors. The SREBP-1 gene encodes two different isoforms, SREBP-1a and -1c, that are expressed at varying levels in different tissues and cultured cells and exhibit common and distinct functions. We identified an additional SREBP-1 isoform, termed SREBP-1ac, and determined its mRNA abundance in different human tissues and cell lines. SREBP-1ac mRNA was detectable in all tissues studied, although at lower levels than the major SREBP-1a and -1c isoforms. Transcription of the novel SREBP isoform was not induced by insulin or cholesterol depletion. SREBP-1ac did not transactivate the human LDLR and UCP2 promoters but robustly attenuated the transactivation capacity of SREBP-1a, -1c and -2 in cotransfection experiments. PMID:16153721

  18. Modified bimolecular fluorescence complementation assay to study the inhibition of transcription complex formation by JAZ proteins.

    PubMed

    Qi, Tiancong; Song, Susheng; Xie, Daoxin

    2013-01-01

    The jasmonate (JA) ZIM-domain (JAZ) proteins of Arabidopsis thaliana repress JA signaling and negatively regulate the JA responses. Recently, JAZ proteins have been found to inhibit the transcriptional function of several transcription factors, among which the basic helix-loop-helix (bHLH) (GLABRA3 [GL3], ENHANCER OF GLABRA3 [EGL3], and TRANSPARENT TESTA8 [TT8]) and R2R3-MYB (GL1 and MYB75) that can interact with each other to form bHLH-MYB complexes and further control gene expression. The bimolecular fluorescence complementation (BiFC) assay is a widely used technique to study protein-protein interactions in living cells. Here we describe a modified BiFC experimental procedure to study the inhibition of the formation of the bHLH (GL3)-MYB (GL1) complex by JAZ proteins. PMID:23615997

  19. A genomewide survey of bHLH transcription factors in the coral Acropora digitifera identifies three novel orthologous families, pearl, amber, and peridot.

    PubMed

    Gyoja, Fuki; Kawashima, Takeshi; Satoh, Nori

    2012-04-01

    Decoding the genome of the coral, Acropora digitifera, enabled us to characterize a nearly full set of 70 basic helix-loop-helix (bHLH) transcription factors in this organism. This number is comparable to 68 bHLH genes in the sea anemone, Nematostella vectensis, and larger than those in most other invertebrate metazoans. The 70 bHLH genes were assigned to 29 orthologous families previously reported. In addition, we identified three novel HLH orthologous families, which we designated pearl, amber, and peridot, increasing the number of orthologous families to 32. Pearl and amber orthologues were found in genomes and expressed sequenced tags (ESTs) of Mollusca and Annelida in addition to Cnidaria. Peridot orthologues were found in genomes and ESTs of Cephalochordata and Hemichordata in addition to Cnidaria. These three genes were likely lost in the clades of Drosophila melanogaster, Caenorhabditis elegans, and Homo sapiens during animal evolution. PMID:22419240

  20. Identification and characterization of a twist ortholog in the polychaete annelid Platynereis dumerilii reveals mesodermal expression of Pdu-twist.

    PubMed

    Pfeifer, Kathrin; Schaub, Christoph; Wolfstetter, Georg; Dorresteijn, Adriaan

    2013-09-01

    The basic helix-loop-helix transcription factor twist plays a key role during mesoderm development in Bilateria. In this study, we identified a twist ortholog in the polychaete annelid Platynereis dumerilii and analyze its expression during larval development, postlarval growth up to the adult stage, and caudal regeneration after amputation of posterior segments. At late larval stages, Pdu-twist is expressed in the mesodermal anlagen and in developing muscles. During adulthood and caudal regeneration, Pdu-twist is expressed in the posterior growth zone, in mesodermal cells within the newly forming segments and budding parapodia. Our results indicate that Pdu-twist is involved in mesoderm formation during larval development, posterior growth, and caudal regeneration. PMID:23817621

  1. Network Theory Inspired Analysis of Time-Resolved Expression Data Reveals Key Players Guiding P. patens Stem Cell Development

    PubMed Central

    Busch, Hauke; Boerries, Melanie; Rensing, Stefan A.

    2013-01-01

    Transcription factors (TFs) often trigger developmental decisions, yet, their transcripts are often only moderately regulated and thus not easily detected by conventional statistics on expression data. Here we present a method that allows to determine such genes based on trajectory analysis of time-resolved transcriptome data. As a proof of principle, we have analysed apical stem cells of filamentous moss (P. patens) protonemata that develop from leaflets upon their detachment from the plant. By our novel correlation analysis of the post detachment transcriptome kinetics we predict five out of 1,058 TFs to be involved in the signaling leading to the establishment of pluripotency. Among the predicted regulators is the basic helix loop helix TF PpRSL1, which we show to be involved in the establishment of apical stem cells in P. patens. Our methodology is expected to aid analysis of key players of developmental decisions in complex plant and animal systems. PMID:23637751

  2. Stress-responsive gene ICE1 from Vitis amurensis increases cold tolerance in tobacco.

    PubMed

    Dong, Chang; Zhang, Zhen; Ren, Junpeng; Qin, Yang; Huang, Jinfeng; Wang, Yan; Cai, Binhua; Wang, Bailin; Tao, Jianmin

    2013-10-01

    We report the identification of the inducer of CBF expression 1 (ICE1) from Vitis amurensis, an upstream transcription factor that regulates the transcription of CBF-like genes. The structure of the basic helix-loop-helix domain of VaICE1 is closely related to that of ICE1 in woody plants. This gene is strongly induced in leaves, roots, stems, and petioles by cold temperature. With longer duration of exposure to cold treatments, the expression patterns of organs exhibit differences, which are not observed in normal condition. Transgenic tobacco over-expressing VaICE1 has higher chilling tolerance and survival ability by improving the activities of superoxide dismutase, peroxidase, and catalase, as well as the chlorophyll yield. PMID:23968929

  3. Overexpression of a homopeptide repeat-containing bHLH protein gene (OrbHLH001) from Dongxiang Wild Rice confers freezing and salt tolerance in transgenic Arabidopsis.

    PubMed

    Li, Fei; Guo, Siyi; Zhao, Yuan; Chen, Dazhou; Chong, Kang; Xu, Yunyuan

    2010-09-01

    Dongxiang Wild Rice (Oryza rufipogon) is the northernmost wild rice in the world known to date and has extremely high cold tolerance and many other adversity-resistant properties. To identify the genes responsible for the high stress tolerance, we isolated and characterized a basic helix-loop-helix (bHLH) protein gene OrbHLH001 from Dongxiang Wild Rice. The gene encodes an ICE1-like protein containing multiple homopeptide repeats. Expression of OrbHLH001 is induced by salt stress and is predominant in the shoots of wild rice seedlings. Overexpression of OrbHLH001 enhanced the tolerance to freezing and salt stresses in transgenic Arabidopsis. Examination of the expression of cold-responsive genes in transgenic Arabidopsis showed that the function of OrbHLH001 differs from that of ICE1 and is independent of a CBF/DREB1 cold-response pathway. PMID:20559833

  4. Direct roles of SPEECHLESS in the specification of stomatal self-renewing cells

    PubMed Central

    Lau, On Sun; Davies, Kelli A.; Chang, Jessica; Adrian, Jessika; Rowe, Matthew H.; Ballenger, Catherine E.; Bergmann, Dominique C.

    2015-01-01

    Lineage-specific stem cells are critical for the production and maintenance of specific cell types and tissues in multicellular organisms. In Arabidopsis, the initiation and proliferation of stomatal lineage cells is controlled by the basic helix-loop-helix transcription factor SPEECHLESS (SPCH). SPCH-driven asymmetric and self-renewing divisions allow flexibility in stomatal production and overall organ growth. How SPCH directs stomatal lineage cell behaviors, however, is unclear. Here, we improved the chromatin immunoprecipitation (ChIP) assay and profiled the genome-wide targets of Arabidopsis SPCH in vivo. We found that SPCH controls key regulators of cell fate and asymmetric cell divisions and modulates responsiveness to peptide and phytohormone-mediated intercellular communication. Our results delineate the molecular pathways that regulate an essential adult stem cell lineage in plants. PMID:25190717

  5. A Mitogen-Activated Protein Kinase Cascade Module, MKK3-MPK6 and MYC2, Is Involved in Blue Light-Mediated Seedling Development in Arabidopsis[C][W

    PubMed Central

    Sethi, Vishmita; Raghuram, Badmi; Sinha, Alok Krishna; Chattopadhyay, Sudip

    2014-01-01

    Mitogen-activated protein kinase (MAPK) pathways are involved in several signal transduction processes in eukaryotes. Light signal transduction pathways have been extensively studied in plants; however, the connection between MAPK and light signaling pathways is currently unknown. Here, we show that MKK3-MPK6 is activated by blue light in a MYC2-dependent manner. MPK6 physically interacts with and phosphorylates a basic helix-loop-helix transcription factor, MYC2, and is phosphorylated by a MAPK kinase, MKK3. Furthermore, MYC2 binds to the MPK6 promoter and regulates its expression in a feedback regulatory mechanism in blue light signaling. We present mutational and physiological studies that illustrate the function of the MKK3-MPK6-MYC2 module in Arabidopsis thaliana seedling development and provide a revised mechanistic view of photomorphogenesis. PMID:25139007

  6. Launching the T-Lineage Developmental Programme

    PubMed Central

    Rothenberg, Ellen V.; Moore, Jonathan E.; Yui, Mary A.

    2011-01-01

    Preface Multipotent blood progenitor cells enter the thymus and begin a protracted differentiation process in which they gradually acquire T-cell characteristics while shedding their legacy of developmental plasticity. Notch signalling and basic helix-loop-helix E-protein transcription factors collaborate repeatedly to trigger and sustain this process throughout the period leading up to T-cell lineage commitment. Nevertheless, the process is discontinuous with separately regulated steps that demand roles for additional collaborating factors. This review discusses new evidence on the coordination of specification and commitment in the early T-cell pathway; effects of microenvironmental signals; the inheritance of stem-cell regulatory factors; and the ensemble of transcription factors that modulate the effects of Notch and E proteins, to distinguish individual stages and to polarize T-lineage fate determination. PMID:18097446

  7. Exploring Functional Redundancy in the Immunoglobulin μ Heavy-Chain Gene Enhancer

    PubMed Central

    Dang, Wei; Nikolajczyk, Barbara S.; Sen, Ranjan

    1998-01-01

    Immunoglobulin (Ig) μ heavy-chain gene enhancer activity is mediated by multiple DNA binding proteins. Mutations of several protein binding sites in the enhancer do not affect enhancer activity significantly. This feature, termed redundancy, is thought to be due to functional compensation of the mutated sites by other elements within the enhancer. In this study, we identified the elements that make the basic helix-loop-helix (bHLH) protein binding sites, μE2 and μE3, redundant. The major compensatory element is a binding site for interferon regulatory factors (IRFs) and not one of several other bHLH protein binding sites. These studies also provide the first evidence for a role of IRF proteins in Ig heavy-chain gene expression. In addition, we reconstituted the activity of a monomeric μ enhancer in nonlymphoid cells and defined the domains of the ETS gene required for function. PMID:9774700

  8. Homeodomain-Leucine Zipper II family of transcription factors to the limelight: central regulators of plant development.

    PubMed

    Carabelli, Monica; Turchi, Luana; Ruzza, Valentino; Morelli, Giorgio; Ruberti, Ida

    2013-09-01

    The Arabidopsis genome encodes 10 Homeodomain-Leucine Zipper (HD-Zip) II transcription factors that can be subdivided into 4 clades (α-δ). All the γ (ARABIDOPSIS THALIANA HOMEOBOX 2 [ATHB2], HOMEOBOX ARABIDOPSIS THALIANA 1 [HAT1], HAT2) and δ (HAT3, ATHB4) genes are regulated by light quality changes (Low Red [R]/Far-Red [FR]) that induce the shade avoidance response in most of the angiosperms. HD-Zip IIγ and HD-Zip IIδ transcription factors function as positive regulators of shade avoidance, and there is evidence that at least ATHB2 is directly positively regulated by the basic Helix-Loop-Helix (bHLH) proteins PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PIF5. Recent evidence demonstrate that, in addition to their function in shade avoidance, HD-Zip IIγ and HD-Zip IIδ proteins play an essential role in plant development from embryogenesis onwards in a white light environment. PMID:23838958

  9. Proprioceptor pathway development is dependent on Math1

    NASA Technical Reports Server (NTRS)

    Bermingham, N. A.; Hassan, B. A.; Wang, V. Y.; Fernandez, M.; Banfi, S.; Bellen, H. J.; Fritzsch, B.; Zoghbi, H. Y.

    2001-01-01

    The proprioceptive system provides continuous positional information on the limbs and body to the thalamus, cortex, pontine nucleus, and cerebellum. We showed previously that the basic helix-loop-helix transcription factor Math1 is essential for the development of certain components of the proprioceptive pathway, including inner-ear hair cells, cerebellar granule neurons, and the pontine nuclei. Here, we demonstrate that Math1 null embryos lack the D1 interneurons and that these interneurons give rise to a subset of proprioceptor interneurons and the spinocerebellar and cuneocerebellar tracts. We also identify three downstream genes of Math1 (Lh2A, Lh2B, and Barhl1) and establish that Math1 governs the development of multiple components of the proprioceptive pathway.

  10. Nuclear localized protein-1 (Nulp1) increases cell death of human osteosarcoma cells and binds the X-linked inhibitor of apoptosis protein

    SciTech Connect

    Steen, Hakan; Lindholm, Dan

    2008-02-08

    Nuclear localized protein-1 (Nulp1) is a recently identified gene expressed in mouse and human tissues particularly during embryonic development. Nulp1 belongs to the family of basic helix-loop-helix (bHLH) proteins that are important in development. The precise function of Nulp1 in cells is however not known. We observed that overexpression of Nulp1 induces a large increase in cell death of human osteosarcoma Saos2 cells with DNA fragmentation. In mouse N2A neuroblastoma cells Nulp1 affected cell proliferation and sensitized cells towards death induced by staurosporine. Staining using a novel antibody localized Nulp1 mainly to the cell nucleus and to some extent to the cytoplasm. Nulp1 binds the X-linked inhibitor of apoptosis protein (XIAP) and this interaction was increased during cell death. These results indicate that Nulp1 plays a role in cell death control and may influence tumor growth.

  11. Aryl Hydrocarbon Receptor Control of Adaptive Immunity

    PubMed Central

    2013-01-01

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that belongs to the family of basic helix-loop-helix transcription factors. Although the AhR was initially recognized as the receptor mediating the pathologic effects of dioxins and other pollutants, the activation of AhR by endogenous and environmental factors has important physiologic effects, including the regulation of the immune response. Thus, the AhR provides a molecular pathway through which environmental factors modulate the immune response in health and disease. In this review, we discuss the role of AhR in the regulation of the immune response, the source and chemical nature of AhR ligands, factors controlling production and degradation of AhR ligands, and the potential to target the AhR for therapeutic immunomodulation. PMID:23908379

  12. Grasses use an alternatively wired bHLH transcription factor network to establish stomatal identity.

    PubMed

    Raissig, Michael T; Abrash, Emily; Bettadapur, Akhila; Vogel, John P; Bergmann, Dominique C

    2016-07-19

    Stomata, epidermal valves facilitating plant-atmosphere gas exchange, represent a powerful model for understanding cell fate and pattern in plants. Core basic helix-loop-helix (bHLH) transcription factors regulating stomatal development were identified in Arabidopsis, but this dicot's developmental pattern and stomatal morphology represent only one of many possibilities in nature. Here, using unbiased forward genetic screens, followed by analysis of reporters and engineered mutants, we show that stomatal initiation in the grass Brachypodium distachyon uses orthologs of stomatal regulators known from Arabidopsis but that the function and behavior of individual genes, the relationships among genes, and the regulation of their protein products have diverged. Our results highlight ways in which a kernel of conserved genes may be alternatively wired to produce diversity in patterning and morphology and suggest that the stomatal transcription factor module is a prime target for breeding or genome modification to improve plant productivity. PMID:27382177

  13. Potential for neural regeneration after neurotoxic injury in the adult mammalian retina

    NASA Astrophysics Data System (ADS)

    Ooto, Sotaro; Akagi, Tadamichi; Kageyama, Ryoichiro; Akita, Joe; Mandai, Michiko; Honda, Yoshihito; Takahashi, Masayo

    2004-09-01

    It has long been believed that the retina of mature mammals is incapable of regeneration. In this study, using the N-methyl-D-aspartate neurotoxicity model of adult rat retina, we observed that some Müller glial cells were stimulated to proliferate in response to a toxic injury and produce bipolar cells and rod photoreceptors. Although these newly produced neurons were limited in number, retinoic acid treatment promoted the number of regenerated bipolar cells. Moreover, misexpression of basic helix-loop-helix and homeobox genes promoted the induction of amacrine, horizontal, and rod photoreceptor specific phenotypes. These findings demonstrated that retinal neurons regenerated even in adult mammalian retina after toxic injury. Furthermore, we could partially control the fate of the regenerated neurons with extrinsic factors or intrinsic genes. The Müller glial cells constitute a potential source for the regeneration of adult mammalian retina and can be a target for drug delivery and gene therapy in retinal degenerative diseases.

  14. Cloning of a factor required for activity of the Ah (dioxin) receptor

    SciTech Connect

    Hoffman, E.C.; Reyes, H.; Chu, Fongfong; Sander, F.; Conley, L.H.; Brooks, B.A.; Hankinson, O. )

    1991-05-17

    The aryl hydrocarbon (Ah) receptor binds various environmental pollutants, such as polycyclic aromatic hydrocarbons, heterocyclic amines, and polychlorinated aromatic compounds (dioxins, dibenzofurans, and biphenyls), and mediates the carcinogenic effects of these agents. The complementary DNA and part of the gene for an 87-kilodalton human protein that is necessary for Ah receptor function have been cloned. The protein is not the ligand-binding subunit of the receptor but is a factor that is required for the ligand-binding subunit to translocate from the cytosol to the nucleus after binding ligand. The requirement for this factor distinguishes the Ah receptor from the glucocorticoid receptor, to which the Ah receptor has been presumed to be similar. Two portions of the 87-kilodalton protein share sequence similarities with two Drosophila proteins, Per and Sim. Another segment of the protein shows conformity to the consensus sequence for the basic helix-loop-helix motif found in proteins that bind DNA as homodimers or heterodimers.

  15. Structural basis of nucleic acid recognition by FK506-binding protein 25 (FKBP25), a nuclear immunophilin

    PubMed Central

    Prakash, Ajit; Shin, Joon; Rajan, Sreekanth; Yoon, Ho Sup

    2016-01-01

    The nuclear immunophilin FKBP25 interacts with chromatin-related proteins and transcription factors and is suggested to interact with nucleic acids. Currently the structural basis of nucleic acid binding by FKBP25 is unknown. Here we determined the nuclear magnetic resonance (NMR) solution structure of full-length human FKBP25 and studied its interaction with DNA. The FKBP25 structure revealed that the N-terminal helix-loop-helix (HLH) domain and C-terminal FK506-binding domain (FKBD) interact with each other and that both of the domains are involved in DNA binding. The HLH domain forms major-groove interactions and the basic FKBD loop cooperates to form interactions with an adjacent minor-groove of DNA. The FKBP25–DNA complex model, supported by NMR and mutational studies, provides structural and mechanistic insights into the nuclear immunophilin-mediated nucleic acid recognition. PMID:26762975

  16. Characterization and developmental expression of xSim, a Xenopus bHLH/PAS gene related to the Drosophila neurogenic master gene single-minded.

    PubMed

    Coumailleau, P; Penrad-Mobayed, M; Lecomte, C; Bollérot, K; Simon, F; Poellinger, L; Angelier, N

    2000-12-01

    We have isolated a novel gene from Xenopus, denominated xSim, which encodes a protein of 760 amino acids containing a basic helix-loop-helix (bHLH) motif contiguous to a PAS domain characteristic of an emerging family of transcriptional regulators so called bHLH/PAS. xSim shares a strong amino acid sequence identity with the Drosophila Single-minded (dSim) and with the murine Sim1 and Sim2 proteins. Phylogenetic analysis reveals that xSim gene is an ortholog gene of the mSim2 gene. Spatio-temporal analysis shows a maternal and a zygotic expression of xSim throughout early Xenopus development. In situ hybridization assays reveal that the transcripts are enriched in the animal hemisphere until blastula stage and extend to the marginal zone at early gastrula stage. As development proceeds, xSim is mainly restricted to the central nervous system. PMID:11091086

  17. Basic Skills--Basic Business.

    ERIC Educational Resources Information Center

    Conference Board of Canada, Ottawa (Ontario).

    The experience of eight prominent Canadian business organizations was examined in terms of how basic skills deficits are identified in their work force, the impact of those deficiencies on organizational competitiveness, and why corporate programs are developed in response to the issue. Some of the key findings were as follows: (1) employee…

  18. Evolution of transcriptional control of the IgH locus: characterization, expression, and function of TF12/HEB homologs of the catfish.

    PubMed

    Hikima, Jun-Ichi; Cioffi, Christopher C; Middleton, Darlene L; Wilson, Melanie R; Miller, Norman W; Clem, L William; Warr, Gregory W

    2004-11-01

    The transcriptional enhancer (Emu3') of the IgH locus of the channel catfish, Ictalurus punctatus, differs from enhancers of the mammalian IgH locus in terms of its position, structure, and function. Transcription factors binding to multiple octamer motifs and a single muE5 motif (an E-box site, consensus CANNTG) interact for its function. E-box binding transcription factors of the class I basic helix-loop-helix family were cloned from a catfish B cell cDNA library in this study, and homologs of TF12/HEB were identified as the most highly represented E-proteins. Two alternatively spliced forms of catfish TF12 (termed CFEB1 and -2) were identified and contained regions homologous to the basic helix-loop-helix and activation domains of other vertebrate E-proteins. CFEB message is widely expressed, with CFEB1 message predominating over that of CFEB2. Both CFEB1 and -2 strongly activated transcription from a muE5-dependent artificial promoter. In catfish B cells, CFEB1 and -2 also activated transcription from the core region of the catfish IgH enhancer (Emu3') in a manner dependent on the presence of the muE5 site. Both CFEB1 and -2 bound the muE5 motif, and formed both homo- and heterodimers. CFEB1 and -2 were weakly active or inactive (in a promoter-dependent fashion) in mammalian B-lineage cells. Although E-proteins have been highly conserved in vertebrate evolution, the present results indicate that, at the phylogenetic level of a teleost fish, the TF12/HEB homolog differs from that of mammals in terms of 1) its high level of expression and 2) the presence of isoforms generated by alternative RNA processing. PMID:15494495

  19. E2A promotes the survival of precursor and mature B lymphocytes.

    PubMed

    Lazorchak, Adam S; Wojciechowski, Jason; Dai, Meifang; Zhuang, Yuan

    2006-08-15

    The basic helix-loop-helix transcription factor E2A is an essential regulator of B lymphocyte lineage commitment and is required to activate the expression of numerous B lineage-specific genes. Studies involving ectopic expression of Id proteins, which inhibit E2A as well as other basic helix-loop-helix proteins such as HEB, suggest additional roles of E2A at later stages of B cell development. We use E2A-deficient and E2A and HEB double-deficient pre-B cell lines to directly assess the function of E2A and HEB in B cell development after lineage commitment. We show that, in contrast to the established role of E2A in lineage commitment, elimination of E2A and HEB in pre-B cell lines has only a modest negative impact on B lineage gene expression. However, E2A single and E2A and HEB double-deficient but not HEB single-deficient cell lines show dramatically enhanced apoptosis upon growth arrest. To address the possible role of E2A in the regulation of B cell survival in vivo, we crossed IFN-inducible Cre-transgenic mice to E2A conditional mice. Cre-mediated E2A deletion resulted in a block in bone marrow B cell development and a significant reduction in the proportion and total number of splenic B cells in these mice. We show that Cre-mediated deletion of E2A in adoptively transferred mature B cells results in the rapid depletion of the transferred population within 24 h of Cre induction. These results reveal that E2A is not required to maintain B cell fate but is essential in promoting pre-B and B cell survival. PMID:16888011

  20. Eya1 and Six1 are essential for early steps of sensory neurogenesis in mammalian cranial placodes.

    PubMed

    Zou, Dan; Silvius, Derek; Fritzsch, Bernd; Xu, Pin-Xian

    2004-11-01

    Eya1 encodes a transcriptional co-activator and is expressed in cranial sensory placodes. It interacts with and functions upstream of the homeobox gene Six1 during otic placodal development. Here, we have examined their role in cranial sensory neurogenesis. Our data show that the initial cell fate determination for the vestibuloacoustic neurons and their delamination appeared to be unaffected in the absence of Eya1 or Six1 as judged by the expression of the basic helix-loop-helix genes, Neurog1 that specifies the neuroblast cell lineage, and Neurod that controls neuronal differentiation and survival. However, both genes are necessary for normal maintenance of neurogenesis. During the development of epibranchial placode-derived distal cranial sensory ganglia, while the phenotype appears less severe in Six1 than in Eya1 mutants, an early arrest of neurogenesis was observed in the mutants. The mutant epibranchial progenitor cells fail to express Neurog2 that is required for the determination of neuronal precursors, and other basic helix-loop-helix as well as the paired homeobox Phox2 genes that are essential for neural differentiation and maintenance. Failure to activate their normal differentiation program resulted in abnormal apoptosis of the progenitor cells. Furthermore, we show that disruption of viable ganglion formation leads to pathfinding errors of branchial motoneurons. Finally, our results suggest that the Eya-Six regulatory hierarchy also operates in the epibranchial placodal development. These findings uncover an essential function for Eya1 and Six1 as critical determination factors in acquiring both neuronal fate and neuronal subtype identity from epibranchial placodal progenitors. These analyses define a specific role for both genes in early differentiation and survival of the placodally derived cranial sensory neurons. PMID:15496442

  1. The genetics of rhizosheath size in a multiparent mapping population of wheat

    PubMed Central

    Delhaize, Emmanuel; Rathjen, Tina M.; Cavanagh, Colin R.

    2015-01-01

    Rhizosheaths comprise soil that adheres to plant roots and, in some species, are indicative of root hair length. In this study, the genetics of rhizosheath size in wheat was investigated by screening the progeny of multiparent advanced generation intercrosses (MAGIC). Two MAGIC populations were screened for rhizosheath size using a high throughput method. One MAGIC population was developed from intercrosses between four parents (4-way) and the other from intercrosses between eight parents (8-way). Transgressive segregation for rhizosheath size was observed in both the 4-way and 8-way MAGIC populations. A quantitative trait loci (QTL) analysis of the 4-way population identified six major loci located on chromosomes 2B, 4D, 5A, 5B, 6A, and 7A together accounting for 42% of the variation in rhizosheath size. Rhizosheath size was strongly correlated with root hair length and was robust across different soil types in the absence of chemical constraints. Rhizosheath size in the MAGIC populations was a reliable surrogate for root hair length and, therefore, the QTL identified probably control root hair elongation. Members of the basic helix-loop-helix family of transcription factors have previously been identified to regulate root hair length in Arabidopsis and rice. Since several wheat members of the basic helix-loop-helix family of genes are located within or near the QTL, these genes are candidates for controlling the long root hair trait. The QTL for rhizosheath size identified in this study provides the opportunity to implement marker-assisted selection to increase root hair length for improved phosphate acquisition in wheat. PMID:25969556

  2. Phosphorylation in intrinsically disordered regions regulates the activity of Neurogenin2

    PubMed Central

    2014-01-01

    Background Neuronal differentiation is largely under the control of basic Helix-Loop-Helix (bHLH) proneural transcription factors that play key roles during development of the embryonic nervous system. In addition to well-characterised regulation of their expression, increasing evidence is emerging for additional post-translational regulation of proneural protein activity. Of particular interest is the bHLH proneural factor Neurogenin2 (Ngn2), which orchestrates progression from neural progenitor to differentiated neuron in several regions of the central nervous system. Previous studies have demonstrated a key role for cell cycle-dependent multi-site phosphorylation of Ngn2 protein at Serine-Proline (SP) sites for regulation of its neuronal differentiation activity, although the potential structural and functional consequences of phosphorylation at different regions of the protein are unclear. Results Here we characterise the role of phosphorylation of specific regions of Ngn2 on the stability of Ngn2 protein and on its neuronal differentiation activity in vivo in the developing embryo, demonstrating clearly that the location of SP sites is less important than the number of SP sites available for control of Ngn2 activity in vivo. We also provide structural evidence that Ngn2 contains large, intrinsically disordered regions that undergo phosphorylation by cyclin-dependent kinases (cdks). Conclusions Phosphorylation of Ngn2 occurs in both the N- and C-terminal regions, either side of the conserved basic Helix-Loop-Helix domain. While these phosphorylation events do not change the intrinsic stability of Ngn2, phosphorylation on multiple sites acts to limit its ability to drive neuronal differentiation in vivo. Phosphorylated regions of Ngn2 are predicted to be intrinsically disordered and cdk-dependent phosphorylation of these intrinsically disordered regions contributes to Ngn2 regulation. PMID:25374254

  3. Characterization of msim, a murine homologue of the Drosophila sim transcription factor

    SciTech Connect

    Moffett, P.; Reece, M.; Pelletier, J.

    1996-07-01

    Mutations in the Drosophila single-minded (sim) gene result in loss of precursor cells that give rise to midline cells of the embryonic central nervous system. During the course of an exon-trapping strategy aimed at identifying transcripts that contribute to the etiology and pathophysiology of Down syndrome, we identified a human exon from the Down syndrome, we identified a human exon from the Down syndrome critical region showing significantly homology to the Drosophila sim gene. Using a cross-hybridization approach, we have isolated a murine homolog of Drosophila sim gene, which we designated msim. Nucleotide and predicted amino acid sequence analyses of msim cDNA clones indicate the this gene encodes a member of the basic-helix-loop-helix class of transcription factors. The murine and Drosophila proteins share 88% residues within the basic-helix-loop helix domain, with an overall homology of 92%. In addition, the N-terminal domain of MSIM contains two PAS dimerization motifs also featured in the Drosophila sim gene product, as well as a small number of other transcription factors. Northern blot analysis of adult murine tissues revealed that the msim gene produces a single mRNA species of {approximately}4 kb expressed in a small number of tissues, with the highest levels in the kidneys and lower levels present in skeletal muscle, lung, testis, brain, and heart. In situ hybridization experiments demonstrate that msim is also expressed in early fetal development in the central nervous system and in cartilage primordia. The characteristics of the msim gene are consistent with its putative function as a transcriptional regulator. 51 refs., 6 figs., 1 tab.

  4. Characterization of msim, a murine homologue of the Drosophila sim transcription factor.

    PubMed

    Moffett, P; Dayo, M; Reece, M; McCormick, M K; Pelletier, J

    1996-07-01

    Mutations in the Drosophila single-minded (sim) gene result in loss of precursor cells that give rise to midline cells of the embryonic central nervous system. During the course of an exon-trapping strategy aimed at identifying transcripts that contribute to the etiology and pathophysiology of Down syndrome, we identified a human exon from the Down syndrome critical region showing significant homology to the Drosophila sim gene. Using a cross-hybridization approach, we have isolated a murine homolog of the Drosophila sim gene, which we designated msim. Nucleotide and predicted amino acid sequence analyses of msim cDNA clones indicate that this gene encodes a member of the basic-helix-loop-helix class of transcription factors. The murine and Drosophila proteins share 88% residues within the basic-helix-loop-helix domain, with an overall homology of 92%. In addition, the N-terminal domain of MSIM contains two PAS dimerization motifs also featured in the Drosophila sim gene product, as well as a small number of other transcription factors. Northern blot analysis of adult murine tissues revealed that the msim gene produces a single mRNA species of approximately 4 kb expressed in a small number of tissues, with the highest levels in the kidneys and lower levels present in skeletal muscle, lung, testis, brain, and heart. In situ hybridization experiments demonstrate that msim is also expressed in early fetal development in the central nervous system and in cartilage primordia. The characteristics of the msim gene are consistent with its putative function as a transcriptional regulator. PMID:8661115

  5. Mutations Affecting the BHLHA9 DNA-Binding Domain Cause MSSD, Mesoaxial Synostotic Syndactyly with Phalangeal Reduction, Malik-Percin Type

    PubMed Central

    Malik, Sajid; Percin, Ferda E.; Bornholdt, Dorothea; Albrecht, Beate; Percesepe, Antonio; Koch, Manuela C.; Landi, Antonio; Fritz, Barbara; Khan, Rizwan; Mumtaz, Sara; Akarsu, Nurten A.; Grzeschik, Karl-Heinz

    2014-01-01

    Mesoaxial synostotic syndactyly, Malik-Percin type (MSSD) (syndactyly type IX) is a rare autosomal-recessive nonsyndromic digit anomaly with only two affected families reported so far. We previously showed that the trait is genetically distinct from other syndactyly types, and through autozygosity mapping we had identified a locus on chromosome 17p13.3 for this unique limb malformation. Here, we extend the number of independent pedigrees from various geographic regions segregating MSSD to a total of six. We demonstrate that three neighboring missense mutations affecting the highly conserved DNA-binding region of the basic helix-loop-helix A9 transcription factor (BHLHA9) are associated with this phenotype. Recombinant BHLHA9 generated by transient gene expression is shown to be located in the cytoplasm and the cell nucleus. Transcription factors 3, 4, and 12, members of the E protein (class I) family of helix-loop-helix transcription factors, are highlighted in yeast two-hybrid analysis as potential dimerization partners for BHLHA9. In the presence of BHLHA9, the potential of these three proteins to activate expression of an E-box-regulated target gene is reduced considerably. BHLHA9 harboring one of the three substitutions detected in MSSD-affected individuals eliminates entirely the transcription activation by these class I bHLH proteins. We conclude that by dimerizing with other bHLH protein monomers, BHLHA9 could fine tune the expression of regulatory factors governing determination of central limb mesenchyme cells, a function made impossible by altering critical amino acids in the DNA binding domain. These findings identify BHLHA9 as an essential player in the regulatory network governing limb morphogenesis in humans. PMID:25466284

  6. Sunspace basics

    SciTech Connect

    Not Available

    1994-11-01

    Anyone who lives in a home with a sunspace will tell you that the sunspace is the most enjoyable room in the house. Many times the homeowner`s only regret is that the sunspace is not larger. Although aesthetics often drive the decision to add a sunspace or include one in a new home design, sunspaces can also provide supplemental space heating and a healthy environment for plants and people. In fact, a well-designed sunspace can provide up to 60% of a home`s winter heating requirements. This publication addresses basic elements of sunspace design; design considerations for supplemental space heating, growing plants, and use as a living space; design guidelines including siting, heat distribution, and glazing angles; and major sunspace components including glazing options, thermal mass, insulation, and climate controls. A list of sources for more information is also provided.

  7. Inflation Basics

    SciTech Connect

    Green, Dan

    2014-03-01

    metrical fluctuations, both scalar and tensor, are also produced in inflationary models. Thus, the time appears to be appropriate for a very basic and simple exposition of the inflationary model written from a particle physics perspective. Only the simplest scalar model will be explored because it is easy to understand and contains all the basic elements of the inflationary model.

  8. Alcohol oxidase protein mediated in-situ synthesized and stabilized gold nanoparticles for developing amperometric alcohol biosensor.

    PubMed

    Chinnadayyala, Somasekhar R; Santhosh, Mallesh; Singh, Naveen K; Goswami, Pranab

    2015-07-15

    A simple one step method for the alcohol oxidases (AOx) protein mediated synthesis of gold nano-particles (AuNPs) in alkaline (pH 8.5) condition with simultaneous stabilization of the nanoparticles on the AOx protein surface under native environment has been developed. The formation of the AOx conjugated AuNPs was confirmed by advanced analytical and spectroscopic techniques. The significant increase in zeta potential (ζ) value of -57mV for the synthesized AOx-AuNPs conjugate from the AOx (pI 4.5) protein (ζ, -30mV) implied good stability of the in-situ synthesized nano-conjugate. The AOx-AuNPs conjugate showed steady stability in alkaline (upto pH 8.5) and NaCl (up to 10(-1)M) solutions. The efficiency (Kcat/Km) of the AuNP conjugated AOx was increased by 18% from the free enzyme confirming the activating role of the surface stabilized AuNPs for the enzyme. The AuNPs-AOx conjugate was encapsulated with polyaniline (PANI) synthesized by oxidative polymerization of aniline using H2O2 generated in-situ from the AOx catalysed oxidation of alcohol. The PANI encapsulated AuNPs-AOx assembly was stabilized on a glassy carbon electrode (GCE) by chitosan-Nafion mixture and then utilized the fabricated bioelectrode for detection of alcohol amperometrically using H2O2 as redox indicator at +0.6V. The constructed biosensor showed high operational stability (6.3% loss after 25 measurements), wide linear detection range of 10µM-4.7mM (R(2)=0.9731), high sensitivity of 68.3±0.35µAmM(-1) and low detection limit of 7±0.027µM for ethanol. The fabricated bioelectrode was successfully used for the selective determination of alcohol in beverage samples. PMID:25725464

  9. Protein mediated membrane adhesion

    NASA Astrophysics Data System (ADS)

    Carlson, Andreas; Mahadevan, L.

    2015-05-01

    Adhesion in the context of mechanical attachment, signaling, and movement in cellular dynamics is mediated by the kinetic interactions between membrane-embedded proteins in an aqueous environment. Here, we present a minimal theoretical framework for the dynamics of membrane adhesion that accounts for the kinetics of protein binding, the elastic deformation of the membrane, and the hydrodynamics of squeeze flow in the membrane gap. We analyze the resulting equations using scaling estimates to characterize the spatiotemporal features of the adhesive patterning and corroborate them using numerical simulations. In addition to characterizing aspects of cellular dynamics, our results might also be applicable to a range of phenomena in physical chemistry and materials science where flow, deformation, and kinetics are coupled to each other in slender geometries.

  10. Adult Basic Education Basic Computer Literacy Handbook.

    ERIC Educational Resources Information Center

    Manini, Catalina M.; Cervantes, Juan

    This handbook, in both English and Spanish versions, is intended for use with adult basic education (ABE) students. It contains five sections of basic computer literacy activities and information about the ABE computer literacy course offered at Dona Ana Community College (DACC) in New Mexico. The handbook begins with forewords by the handbook's…

  11. Integrin αvβ1 Modulation Affects Subtype B Avian Metapneumovirus Fusion Protein-mediated Cell-Cell Fusion and Virus Infection.

    PubMed

    Yun, Bing-Ling; Guan, Xiao-Lu; Liu, Yong-Zhen; Zhang, Yao; Wang, Yong-Qiang; Qi, Xiao-Le; Cui, Hong-Yu; Liu, Chang-Jun; Zhang, Yan-Ping; Gao, Hong-Lei; Gao, Li; Li, Kai; Gao, Yu-Long; Wang, Xiao-Mei

    2016-07-01

    Avian metapneumovirus (aMPV) fusion (F) protein mediates virus-cell membrane fusion to initiate viral infection, which requires F protein binding to its receptor(s) on the host cell surface. However, the receptor(s) for aMPV F protein is still not identified. All known subtype B aMPV (aMPV/B) F proteins contain a conserved Arg-Asp-Asp (RDD) motif, suggesting that the aMPV/B F protein may mediate membrane fusion via the binding of RDD to integrin. When blocked with integrin-specific peptides, aMPV/B F protein fusogenicity and viral replication were significantly reduced. Specifically we identified integrin αv and/or β1-mediated F protein fusogenicity and viral replication using antibody blocking, small interfering RNAs (siRNAs) knockdown, and overexpression. Additionally, overexpression of integrin αv and β1 in aMPV/B non-permissive cells conferred aMPV/B F protein binding and aMPV/B infection. When RDD was altered to RAE (Arg-Ala-Glu), aMPV/B F protein binding and fusogenic activity were profoundly impaired. These results suggest that integrin αvβ1 is a functional receptor for aMPV/B F protein-mediated membrane fusion and virus infection, which will provide new insights on the fusogenic mechanism and pathogenesis of aMPV. PMID:27226547

  12. The Gαi AND Gαq Proteins Mediate the Effects of Melatonin on Steroid/Thyroid Hormone Receptor Transcriptional Activity and Breast Cancer Cell Proliferation

    PubMed Central

    Lai, Ling; Yuan, Lin; Chen, Qi; Dong, Chunmin; Mao, Lulu; Rowan, Brian; Frasch, Tripp; Hill, Steven M.

    2016-01-01

    Melatonin, via its MT1 receptor, but not the MT2 receptor, can modulate the transcriptional activity of various nuclear receptors (ERα and RARα, but not ERβ) in MCF-7, T47D and ZR-75-1 human breast cancer cell lines. The anti-proliferative and nuclear receptor modulatory actions of melatonin are mediated via the MT1 G protein-coupled receptor expressed in human breast cancer cells. However, the specific G proteins and associated pathways involved in nuclear receptor transcriptional regulation by melatonin are not yet clear. Upon activation, the MT1 receptor specifically couples to the Gαi2, Gαi3, Gαq and Gαll proteins, and via activation of Gαi2 proteins, melatonin suppresses forskolin-induced cyclic AMP (cAMP) production, while melatonin activation of Gαq, is able to inhibit phospholipid hydrolysis and ATP’s induction of inositol triphosphate (IP3) production in MCF-7 breast cancer cells. Employing dominant-negative (DN) and dominant-positive (DP) forms of these G proteins we demonstrate that Gαi2 proteins mediate the suppression of estrogen-induced ERα transcriptional activity by melatonin, while the Gq protein mediates the enhancement of retinoid-induced RARα transcriptional activity by melatonin. However, the growth-inhibitory actions of melatonin are mediated via both Gαi2 and Gαq proteins. PMID:18705646

  13. Basic BASIC; An Introduction to Computer Programming in BASIC Language.

    ERIC Educational Resources Information Center

    Coan, James S.

    With the increasing availability of computer access through remote terminals and time sharing, more and more schools and colleges are able to introduce programing to substantial numbers of students. This book is an attempt to incorporate computer programming, using BASIC language, and the teaching of mathematics. The general approach of the book…

  14. PASCAL vs BASIC

    ERIC Educational Resources Information Center

    Mundie, David A.

    1978-01-01

    A comparison between PASCAL and BASIC as general purpose microprocessor languages rates PASCAL above BASIC in such points as program structure, data types, structuring methods, control structures, procedures and functions, and ease in learning. (CMV)

  15. Health Insurance Basics

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Health Insurance Basics KidsHealth > For Teens > Health Insurance Basics Print ... thought advanced calculus was confusing. What Exactly Is Health Insurance? Health insurance is a plan that people buy ...

  16. CSF myelin basic protein

    MedlinePlus

    CSF myelin basic protein is a test to measure the level of myelin basic protein (MBP) in the cerebrospinal fluid (CSF). The CSF ... less than 4 ng/mL of myelin basic protein in the CSF. Normal value ranges may vary ...

  17. Basic Cake Decorating Workbook.

    ERIC Educational Resources Information Center

    Bogdany, Mel

    Included in this student workbook for basic cake decorating are the following: (1) Drawings of steps in a basic way to ice a layer cake, how to make a paper cone, various sizes of flower nails, various sizes and types of tin pastry tubes, and special rose tubes; (2) recipes for basic decorating icings (buttercream, rose paste, and royal icing);…

  18. "Back to Basics" or "Forward to Basics"?

    ERIC Educational Resources Information Center

    Perso, Thelma

    2007-01-01

    Politicians have used the promise of "back to basics in our schools" as an educational platform for some time now, possibly in recognition that this is something the general population perceives as an issue they might just vote for. In the various positions the author has held, both professional and in community service, she has been required to…

  19. The Basic and Semi-Basic

    ERIC Educational Resources Information Center

    Spitler, Gail

    1978-01-01

    Presented is a paradigm for teaching basic and semibasic arithmetic facts to children with arithmetic difficulties, in which the student progresses from the use of concrete materials such as blocks, to the use of diagrams such as tally marks, to a reasoning process, to responding in an automatic manner. (DLS)

  20. Fluency with Basic Addition

    ERIC Educational Resources Information Center

    Garza-Kling, Gina

    2011-01-01

    Traditionally, learning basic facts has focused on rote memorization of isolated facts, typically through the use of flash cards, repeated drilling, and timed testing. However, as many experienced teachers have seen, "drill alone does not develop mastery of single-digit combinations." In contrast, a fluency approach to learning basic addition…

  1. Basic Electronics I.

    ERIC Educational Resources Information Center

    Robertson, L. Paul

    Designed for use in basic electronics programs, this curriculum guide is comprised of twenty-nine units of instruction in five major content areas: Orientation, Basic Principles of Electricity/Electronics, Fundamentals of Direct Current, Fundamentals of Alternating Current, and Applying for a Job. Each instructional unit includes some or all of…

  2. Construction & Basic Skills.

    ERIC Educational Resources Information Center

    BCEL Newsletter for the Business and Literacy Communities, 1991

    1991-01-01

    Basic skills education has become a pressing need in the construction industry as jobs become more complex and fewer workers have needed skills. However, the construction industry lags in spending on training for entry-level workers. The Home Builders Institute (HBI) is testing a pilot basic skills program that it hopes will prove useful to the…

  3. Romanian Basic Course.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    The "Romanian Basic Course," consisting of 89 lesson units in eight volumes, is designed to train native English language speakers to Level 3 proficiency in comprehension, speaking, reading, and writing Romanian (based on a 1-5 scale in which Level 5 is native speaker proficiency). Volume 1, which introduces basic sentences in dialog form with…

  4. Basic Science Training Program.

    ERIC Educational Resources Information Center

    Brummel, Clete

    These six learning modules were developed for Lake Michigan College's Basic Science Training Program, a workshop to develop good study skills while reviewing basic science. The first module, which was designed to provide students with the necessary skills to study efficiently, covers the following topics: time management; an overview of a study…

  5. HEBREW BASIC COURSE.

    ERIC Educational Resources Information Center

    LEVINSON, HANNA; REIF, JOSEPH A.

    THIS HEBREW BASIC COURSE IS INTENDED AS A TRAINING MANUAL TO TEACH STUDENTS THE INFORMAL SPEECH OF EDUCATED NATIVE ISRAELIS AND IS DESIGNED TO BE USED WITH A NATIVE INSTRUCTOR AND TAPE RECORDINGS PREPARED FOR THIS COURSE. THE UNITS CONSIST OF BASIC CONVERSATION, ADDITIONAL VOCABULARY, GRAMMAR NOTES, REVIEW CONVERSATIONS, AND DRILLS ON VOCABULARY,…

  6. BASIC Beats PASCAL.

    ERIC Educational Resources Information Center

    Ever, Jacob

    1981-01-01

    Features of two versions of the BASIC programing language are compared with the features of the PASCAL programing language. The application chosen for comparison was a word processor. The conclusion was that PASCAL had the best language features, but BASIC had better systems capabilities. (MP)

  7. Exponentiation: A New Basic?

    ERIC Educational Resources Information Center

    Davis, Brent

    2015-01-01

    For centuries, the basic operations of school mathematics have been identified as addition, subtraction, multiplication, and division. Notably, these operations are "basic," not because they are foundational to mathematics knowledge, but because they were vital to a newly industrialized and market-driven economy several hundred years…

  8. TOOLS AND BASIC MACHINES.

    ERIC Educational Resources Information Center

    George Washington Univ., Washington, DC. School of Education.

    THIS BASIC READER IS A PART OF AN EXPERIMENTAL CURRICULUM DEVELOPMENT PROJECT DESCRIBED IN VT 004 454, TO DEVELOP AND EVALUATE SPECIAL NEW TRAINING MATERIALS TO TEACH BASIC VOCATIONAL TALENT SKILLS TO DISADVANTAGED STUDENTS WHICH WERE TESTED ON APPROXIMATELY 2,500 EIGHTH AND NINTH GRADERS IN EIGHT SCHOOL SYSTEMS ACROSS THE NATION. THIS READER WAS…

  9. Bracken Basic Concept Scale.

    ERIC Educational Resources Information Center

    Naglieri, Jack A.; Bardos, Achilles N.

    1990-01-01

    The Bracken Basic Concept Scale, for use with preschool and primary-aged children, determines a child's school readiness and knowledge of English-language verbal concepts. The instrument measures 258 basic concepts in such categories as comparisons, time, quantity, and letter identification. This paper describes test administration, scoring and…

  10. Role of arabidopsis MYC and MYB homologs in drought- and abscisic acid-regulated gene expression.

    PubMed Central

    Abe, H; Yamaguchi-Shinozaki, K; Urao, T; Iwasaki, T; Hosokawa, D; Shinozaki, K

    1997-01-01

    In Arabidopsis, the induction of a dehydration-responsive gene, rd22, is mediated by abscisic acid (ABA) and requires protein biosynthesis for ABA-dependent gene expression. Previous experiments established that a 67-bp DNA fragment of the rd22 promoter is sufficient for dehydration- and ABA-induced gene expression and that this DNA fragment contains two closely located putative recognition sites for the basic helix-loop-helix protein MYC and one putative recognition site for MYB. We have carefully analyzed the 67-bp region of the rd22 promoter in transgenic tobacco plants and found that both the first MYC site and the MYB recognition site function as cis-acting elements in the dehydration-induced expression of the rd22 gene. A cDNA encoding a MYC-related DNA binding protein was isolated by DNA-ligand binding screening, using the 67-bp region as a probe, and designated rd22BP1. The rd22BP1 cDNA encodes a 68-kD protein that has a typical DNA binding domain of a basic region helix-loop-helix leucine zipper motif in MYC-related transcription factors. The rd22BP1 protein binds specifically to the first MYC recognition site in the 67-bp fragment. RNA gel blot analysis revealed that transcription of the rd22BP1 gene is induced by dehydration stress and ABA treatment, and its induction precedes that of rd22. We have reported a drought- and ABA-inducible gene that encodes the MYB-related protein ATMYB2. In a transient transactivation experiment using Arabidopsis leaf protoplasts, we demonstrated that both the rd22BP1 and ATMYB2 proteins activate transcription of the rd22 promoter fused to the beta-glucuronidase reporter gene. These results indicate that both the rd22BP1 (MYC) and ATMYB2 (MYB) proteins function as transcriptional activators in the dehydration- and ABA-inducible expression of the rd22 gene. PMID:9368419

  11. HIV Treatment: The Basics

    MedlinePlus

    HIV Treatment HIV Treatment: The Basics (Last updated 3/1/2016; last reviewed 3/1/2016) Key Points Antiretroviral therapy (ART) ... reduces the risk of HIV transmission . How do HIV medicines work? HIV attacks and destroys the infection- ...

  12. Kidney Disease Basics

    MedlinePlus

    ... Links Take the first step Alternate Language URL Kidney Disease Basics Page Content Your kidneys filter extra water ... blood pressure are the most common causes of kidney disease. ​These conditions can slowly damage the kidneys over ...

  13. Video Screen Capture Basics

    ERIC Educational Resources Information Center

    Dunbar, Laura

    2014-01-01

    This article is an introduction to video screen capture. Basic information of two software programs, QuickTime for Mac and BlueBerry Flashback Express for PC, are also discussed. Practical applications for video screen capture are given.

  14. E-Mail Basics.

    ERIC Educational Resources Information Center

    Cohen, Sacha

    1996-01-01

    Offers electronic mail basics, mail etiquette and tips, interesting World Wide Web sites, and how to do a Web search. Includes Web sites that offer beginner tutorials and a glossary of Internet terms. (JOW)

  15. Gq protein mediates UVB-induced cyclooxygenase-2 expression by stimulating HB-EGF secretion from HaCaT human keratinocytes

    SciTech Connect

    Seo, MiRan; Juhnn, Yong-Sung

    2010-03-05

    Ultraviolet (UV) radiation induces cyclooxygenase-2 expression to produce cellular responses including aging and carcinogenesis in skin. We hypothesised that heterotrimeric G proteins mediate UV-induced COX-2 expression by stimulating secretion of soluble HB-EGF (sHB-EGF). In this study, we aimed to elucidate the role and underlying mechanism of the {alpha} subunit of Gq protein (G{alpha}q) in UVB-induced HB-EGF secretion and COX-2 induction. We found that expression of constitutively active G{alpha}q (G{alpha}qQL) augmented UVB-induced HB-EGF secretion, which was abolished by knockdown of G{alpha}q with shRNA in HaCaT human keratinocytes. G{alpha}q was found to mediate the UVB-induced HB-EGF secretion by sequential activation of phospholipase C (PLC), protein kinase C{delta} (PKC{delta}), and matrix metaloprotease-2 (MMP-2). Moreover, G{alpha}qQL mediated UVB-induced COX-2 expression in an HB-EGF-, EGFR-, and p38-dependent manner. From these results, we concluded that G{alpha}q mediates UV-induced COX-2 expression through activation of EGFR by HB-EGF, of which ectodomain shedding was stimulated through sequential activation of PLC, PKC{delta} and MMP-2 in HaCaT cells.

  16. Protein-mediated adhesion of the dissimilatory Fe(III)-reducing bacterium Shewanella alga BrY to hydrous ferric oxide

    SciTech Connect

    Caccavo, F. Jr.

    1999-11-01

    The rate and extent of bacterial Fe(III) mineral reduction are governed by molecular-scale interactions between the bacterial cell surface and the mineral surface. These interactions are poorly understood. This study examined the role of surface proteins in the adhesion of Shewanella alga BrY to hydrous ferric oxide (HFO). Enzymatic degradation of cell surface polysaccharides had no effect on cell adhesion to HFO. The proteolytic enzymes Streptomyces griseus protease and chymotrypsin inhibited the adhesion of S. alga BrY cells to HFO through catalytic degradation of surface proteins. Trypsin inhibited S. alga BrY adhesion solely through surface-coating effects. Protease and chymotrypsin also mediated desorption of adhered S. alga BrY cells from HFO while trypsin did not mediate cell desorption. Protease removed a single peptide band that represented a protein with an apparent molecular mass of 50 kDa. Chymotrypsin removed two peptide bands that represented proteins with apparent molecular masses of 60 and 31 kDa. These proteins represent putative HGO adhesion molecules. A. alga BrY adhesion was inhibited by up to 46% when cells were cultured at sub-MICs of chloramphenicol, suggesting that protein synthesis is necessary for adhesion. Proteins extracted from the surface of S. alga BrY cells inhibited adhesion to HFO by up to 41%. A number of these proteins bound specifically to HFO, suggesting that a complex system of surface proteins mediates S. alga BrY adhesion to HFO.

  17. Cytotoxicity of carteolol to human corneal epithelial cells by inducing apoptosis via triggering the Bcl-2 family protein-mediated mitochondrial pro-apoptotic pathway.

    PubMed

    Shan, Ming; Fan, Ting-Jun

    2016-09-01

    Carteolol is a frequently used nonselective β-adrenoceptor antagonist for glaucoma and ocular hypertension treatment, and its repeated/prolonged usage might be cytotoxic to the cornea, especially the outmost human corneal epithelium (HCEP). The aim of the present study was to characterize the cytotoxicity of carteolol to HCEP and its underlying cellular and molecular mechanisms using an in vitro model of HCEP cells. After HCEP cells were treated with carteolol at concentrations varying from 2% to 0.015625%, the cytotoxicity, apoptosis-inducing effect and pro-apoptotic pathway was investigated, respectively. Our results showed that carteolol at concentrations above 0.03125% induced time- and dose-dependent growth retardation, cytopathic morphological changes and viability decline of HCEP cells. Moreover, carteolol induced G1 phase arrest, plasma membrane permeability elevation, phosphatidylserine externalization, DNA fragmentation, and apoptotic body formation of HCEP cells. Furthermore, carteolol also induced activation of caspase-9 and -3, disruption of mitochondrial transmembrane potential, up-regulation the cytoplasmic amount of cytochrome c and apoptosis-inducing factor, and up-regulation of pro-apoptotic Bax and Bad, down-regulation of anti-apoptotic Bcl-2 and Bcl-xL. In conclusion, carteolol above 1/64 of its clinical therapeutic dosage has a time- and dose-dependent cytotoxicity to HCEP cells, which is achieved by inducing apoptosis via triggering Bcl-2 family protein-mediated mitochondrial pro-apoptotic pathway. PMID:27216471

  18. Protein-mediated layer-by-layer synthesis of TiO₂(B)/anatase/carbon coating on nickel foam as negative electrode material for lithium-ion battery.

    PubMed

    Wang, Xiaobo; Yan, Yong; Hao, Bo; Chen, Ge

    2013-05-01

    Through an aqueous, protein-mediated layer-by-layer titania deposition process, we have fabricated a protamine/titania composite layer on nickel foam. The coating was composed of amorphous carbon and TiO2(B)/anatase nanoparticles and formed upon organic pyrolysis under a reducing atmosphere (5% H2-Ar mixture). X-ray diffraction analyses, Auger electron spectroscopy, and high-resolution transmission electron microscopy revealed that the obtained coatings contained fine monoclinic TiO2(B) and anatase nanocrystals, along with amorphous carbon. Moreover, the coating can be used as a binder-free negative electrode material for lithium-ion batteries and exhibits high reversible capacity and fast charge-discharge properties; a reversible capacity of 245 mAh g(-1) was obtained at a current density of 50 mA g(-1), and capacities of 167 and 143 mAh g(-1) were obtained at current densities of 1 and 2 A g(-1), respectively. PMID:23597025

  19. Basic science highlights.

    PubMed

    Stevenson, Mario

    2007-01-01

    The 14th Conference on Retroviruses and Opportunistic Infections generated a lot of excitement with the announcement of clinical studies employing the use of 2 new classes of antiretroviral drugs that target the viral integrase enzyme and the viral coreceptor CCR5. In addition, a number of presentations on cellular restriction factors provided surprises regarding the mechanism by which cellular restrictions antagonize viral infection. There was also much interest in studies presenting novel cellular cofactors of HIV-1 infection. The conference illustrated how basic science research is paying off. Essential steps in the viral life cycle, uncovered through basic research, are now being targeted by new classes of antiviral agents. In addition, basic science is unveiling potential new targets of antiretroviral therapy. PMID:17485783

  20. Decontamination: back to basics.

    PubMed

    Meredith, Susan J; Sjorgen, Geoff

    2008-07-01

    My invitation from this Journal's Editor, Felicia Cox, to provide a paper for this themed issue, included the sentence 'I was wondering if you or a colleague would like to contribute a back to basics article on the relevant standards and guidelines for decontamination, including what is compliance?'. The reason it is so interesting to me is that the term 'back to basics' implies reverting to a simpler time in life - when by just sticking to the rules, life became easier. However, with decontamination this is not actually true. PMID:18710126

  1. Direct effects of vitamin D3 analogues on G-protein mediated signalling systems in rat osteosarcoma cells and rat pituitary adenoma cells.

    PubMed

    Mortensen, B M; Lund, H W; Jablonski, G; Paulssen, R H; Gordeladze, J O

    1995-06-01

    In normal rats treated with 1,25(OH)2D3 or 24,25(OH)2D3, serum Ca2+, ALP, PRL and GH are significantly altered. In order to study the primary effect of vitamin D3 analogues on target organ function, rat UMR 106 osteosarcoma and GH3 pituitary adenoma cells in monolayer culture were exposed accordingly. Surprisingly, prolonged exposure of these cell lines to physiological levels of either 1,25(OH)2D3 or 24,25(OH)2D3 did not significantly affect the secretory parameters (ALP, PRL or GH) tested. However, 1,25(OH)2D3 exposure significantly reduced PTH- and Gpp(NH)p-elicited AC as well as Gpp(NH)p-stimulated PLC activities in the UMR 106 cells. These changes were accompanied by an increase and decrease in the membrane contents of the G-protein subunits G36 beta and Gq/11 alpha, respectively. In contrast, 24,25(OH)2D3 remained without significant biological effect on these signalling systems despite concomitantly augmented levels of G36 beta. TRH- and Gpp(NH)p-elicited PLC activities in the GH3 cells were significantly reduced by 1,25(OH)2D3 with a concurrent reduction in cellular amounts of Gq/11 alpha, however, 24,25(OH)2D3 did not significantly alter any signalling systems nor G-proteins analyzed. It is concluded that the osteoblastic and pituitary cell secretion of ALP, PRL and GH remain unaffected by the presence of 1,25(OH)2D3 and 24,25(OH)2D3, despite distinct alterations in components of G-protein mediated signalling pathways. Hence, other factors like ambient Ca2+ may be responsible for the perturbed secretory patterns of ALP and PRL seen in vitamin D3 treated rats. PMID:7579039

  2. Attenuation of G protein-mediated inhibition of N-type calcium currents by expression of caveolins in mammalian NG108–15 cells

    PubMed Central

    Toselli, M; Taglietti, V; Parente, V; Flati, S; Pavan, A; Guzzi, F; Parenti, M

    2001-01-01

    Caveolins are integral proteins of glycolipid/cholesterol-rich plasmalemmal caveolae domains, where, they may function as a plasma membrane scaffold onto which many classes of signalling molecules, including receptors and heterotrimeric G proteins, can assemble. To ascertain whether caveolins influence G protein-mediated signal transduction, we stably expressed caveolin-1 and −3 isoforms in the neuroblastoma × glioma NG108–15 hybrid cell line, lacking endogenous caveolins. Subsequently, using whole-cell voltage clamp methods, we examined whether the modulation of N-type voltage-gated Ca2+ channels by Go protein-coupled, δ-type opioid receptors might be affected by recombinant caveolin expression. In transfected NG108–15 cells, caveolins localized at the plasma membrane and, upon subcellular fractionation on sucrose density gradients, they co-localized in Triton-resistant, low buoyancy fractions, with endogenous Go protein α-subunits. The voltage-dependent inhibition of ω-conotoxin GVIA-sensitive Ba2+ currents following either activation of δ-opioid receptors by the agonist [o-pen2,o-pen5]-enkephalin (DPDPE), or direct stimulation of G proteins with guanosine 5′-O-(thiotriphosphate) (GTPγS) was significantly attenuated in caveolin-expressing cells. The kinetics of Ca2+ channel inhibition were also modified by caveolins. Overall, these results suggest that caveolins may negatively affect G protein-dependent regulation of voltage-gated N-type Ca2+ channels, presumably by causing a reduction of the available pool of activated G proteins. PMID:11600672

  3. Hindi Basic Reader.

    ERIC Educational Resources Information Center

    Harter, J. Martin; And Others

    This reader is intended to accompany the Basic Course in Spoken Hindi. Following an outline of the Devanagari script, 20 lessons are presented. Each consists of a reading selection, several illustrative sentences in English and Hindi, and a series of questions. Most of the reading selections were adapted from the magazine "Bal-Bharati." (RM)

  4. Internet Training: The Basics.

    ERIC Educational Resources Information Center

    Gallo, Gail; Wichowski, Chester P.

    This paper outlines the basic information teachers need to know to use the World Wide Web for research and communication, using Netscape 3.04. Topics covered include the following: what is the World Wide Web?; what is a browser?; accessing the Web; moving around a web document; the Uniform Resource Locator (URL); Bookmarks; saving and printing a…

  5. Basic Pneumatics. Instructor's Guide.

    ERIC Educational Resources Information Center

    Fessehaye, Michael

    This instructor's guide is designed for use by industrial vocational teachers in teaching a course on basic pneumatics. Covered in the individual units are the following topics: an introduction to pneumatics (including the operation of a service station hoist); fundamentals and physical laws; air compressors (positive displacement compressors;…

  6. Reading for Basic Understanding.

    ERIC Educational Resources Information Center

    Mercer County Community Coll., Trenton, NJ.

    This document offers materials for a year-long course on general basic reading skills that was part of a workplace literacy project developed by Mercer County Community College (New Jersey), and its partners. The document contains the following: (1) outlines (each of which contains objectives, a topical outline, and list of textbooks) for two…

  7. Navajo Adult Basic Education.

    ERIC Educational Resources Information Center

    Navajo Community Coll., Tsaile, AZ.

    The objectives of this Special Experimental Demonstration Project in Adult Basic Education for the Navajo were: (1) to raise the educational and social level of Navajo adult students who are unable to read, write, and speak English; (2) to assist the Navajo adult students to take advantage of occupational and vocational training programs; (3) to…

  8. Basic Skills Assessment

    ERIC Educational Resources Information Center

    Yin, Alexander C.; Volkwein, J. Fredericks

    2010-01-01

    After surveying 1,827 students in their final year at eighty randomly selected two-year and four-year public and private institutions, American Institutes for Research (2006) reported that approximately 30 percent of students in two-year institutions and nearly 20 percent of students in four-year institutions have only basic quantitative…

  9. Focus on Basics, 1997.

    ERIC Educational Resources Information Center

    Focus on Basics, 1997

    1997-01-01

    Together, these four newsletters contain 36 articles devoted to adult literacy research and practice and the relationship between them. The following articles are included: "A Productive Partnership" (Richard J. Murnane, Bob Bickerton); "Welcome to 'Focus on Basics'" (Barbara Garner); "Applying Research on the Last Frontier" (Karen Backlund, Kathy…

  10. IGBO, BASIC COURSE.

    ERIC Educational Resources Information Center

    SWIFT, LLOYD B.; AND OTHERS

    A BASIC COURSE WAS PREPARED ON THE SPEECH OF TWO MEMBERS OF THE EZINEHITE GROUP OF IGBOS IN EASTERN NIGERIA. THE ESSENTIAL PHONOLOGICAL AND GRAMMATICAL STRUCTURES OF IGBO ARE PRESENTED WITHIN A SMALL VOCABULARY OF APPROXIMATELY 600 ITEMS. THE COURSE MATERIALS CONSIST OF (1) TONE DRILLS, (2) 24 UNITS OF DIALOGS, NOTES, AND DRILLS, (3) SIX UNITS OF…

  11. Swahili Basic Course.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    This basic audiolingual course in standard Swahili appears in six volumes, Lesson Units 1-56. Units consist of a "blueprint" prefatory page outlining the phonological, morphological, and syntactic structures and new vocabulary to be presented; perception drills; Swahili dialog with cartoon guides and English translation; pattern and recombination…

  12. Turkish Basic Course.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    These 14 volumes of the Defense Language Institute's basic course in Turkish consist of 112 lesson units designed to train native English language speakers to Level 3 proficiency in comprehending, speaking, reading, and writing Turkish. (Native-speaker fluency is Level 5.) An introduction to the sound system, vowel harmony, and syllable division…

  13. Korean Basic Course.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    These 11 volumes of the Korean Basic Course comprise 112 lesson units designed to train native English language speakers to Level 3 proficiency in comprehension and speaking and Level 2 proficiency in reading and writing Korean. (Level 5 on this scale is native-speaker level.) Intended for classroom use in the Defense Language Institute intensive…

  14. Portuguese Basic Courses.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    This basic course in Brazilian Portuguese consists of 75 lessons in six volumes. Volume I is in two parts, with the dialogs, questions and exercises presented in Portuguese in the first part, and the intonation patterns and English translations presented in the second. The general format follows the Defense Language Institute format, employing…

  15. Assessing Basic Fact Fluency

    ERIC Educational Resources Information Center

    Kling, Gina; Bay-Williams, Jennifer M.

    2014-01-01

    In this article, the authors share a variety of ways to formatively assess basic fact fluency. The define fluency, raise some issues related to timed testing, and then share a collection of classroom-tested ideas for authentic fact fluency assessment. This article encourages teachers to try a variety of alternative assessments from this sampling,…

  16. Luganda Basic Course.

    ERIC Educational Resources Information Center

    Kamoga, Frederick Katabazi; Stevick, Earl W.

    This "Luganda Basic Course" is not a course in the usual sense. Rather, it is a collection of materials which can be useful in the interaction between teachers and learners. It follows the method by which foreigners interact when they do not speak a common language: personal names and names of respective countries and cities are exchanged.…

  17. Czech Basic Course.

    ERIC Educational Resources Information Center

    Foreign Service (Dept. of State), Washington, DC. Foreign Service Inst.

    This introductory Czech text is based on principles emphasizing development of basic communication skills. Speech samples reflect practical language spoken in everyday situations. The text is designed to be used by American foreign service professionals in foreign countries and to be accompanied by videotapes (unavailable to the public). The text…

  18. MORE BASIC COURSE.

    ERIC Educational Resources Information Center

    LEHR, MARIANNE; AND OTHERS

    THIS BASIC COURSE IN MORE, AN AFRICAN TONE LANGUAGE SPOKEN BY THE MOSSI PEOPLE OF UPPER VOLTA, IS INTENDED TO PROVIDE THE STUDENT WITH DIALOGS THAT RELATE TO SOME OF THE FIRST SITUATIONS IN WHICH HE IS LIKELY TO USE THE LANGUAGE, AS WELL AS WITH SYSTEMATIC PRACTICE IN ALL MAJOR POINTS OF GRAMMAR. THE COURSE COMPRISES 48 UNITS DIVIDED INTO THREE…

  19. Twi Basic Course.

    ERIC Educational Resources Information Center

    Redden, J.E.; And Others

    This course is designed to provide basic structures and vocabulary in Twi in the context of situations commonly encountered by foreigners in Ghana. The dialect presented is Ashanti Twi and the transcription system used is the standard orthography of the Bureau of Ghana Languages with discritic marks added to indicate tone levels. After an…

  20. SHONA BASIC COURSE.

    ERIC Educational Resources Information Center

    STEVICK, EARL W.

    THIS BASIC COURSE IN SHONA, ONE OF THE TWO PRINCIPAL LANGUAGES OF RHODESIA AND PARTS OF ADJACENT MOZAMBIQUE, IS INTENDED TO PROVIDE THE STUDENT WITH DIALOG THAT RELATE TO SOME OF THE SITUATIONS IN WHICH HE IS LIKELY TO USE THE LANGUAGE, AS WELL AS PROVIDE HIM WITH SYSTEMATIC PRACTICE ON ALL MAJOR POINTS OF GRAMMAR. THE TEXT CONSISTS OF 49 UNITS OF…

  1. Microeconomic Analysis with BASIC.

    ERIC Educational Resources Information Center

    Tom, C. F. Joseph

    Computer programs written in BASIC for the study of microeconomic analysis with special emphasis in economic decisions on price, output, and profit of a business firm are described. A very brief overview of the content of each of the 28 computer programs comprising the course is provided; four of the programs are then discussed in greater detail.…

  2. Basics of Weight Control

    MedlinePlus

    ... to: • Eat and drink fewer calories • Increase physical activity • Combine the two for the best results The foods you eat and the beverages you drink provide energy and nutrients. The basic required nutrients are: water, carbohydrates, proteins, fats, dietary fibers, vitamins, and minerals. ...

  3. Basic Media in Education.

    ERIC Educational Resources Information Center

    Harrell, John

    Intended as a guide to the use of different media for use in the classroom, this document demonstrates alternative approaches that may be taken to depicting and communicating images and concepts to others. Some basic tools and materials--including a ruler, matte knife, rubber cement, stapler, felt-tip pens, paint brushes, and lettering pens--are…

  4. Basic Nuclear Physics.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    Basic concepts of nuclear structures, radiation, nuclear reactions, and health physics are presented in this text, prepared for naval officers. Applications to the area of nuclear power are described in connection with pressurized water reactors, experimental boiling water reactors, homogeneous reactor experiments, and experimental breeder…

  5. FULA BASIC COURSE.

    ERIC Educational Resources Information Center

    SWIFT, LLOYD B.; AND OTHERS

    THIS BEGINNING COURSE IS AN INTRODUCTION TO FULA (KNOWN VARIOUSLY AS FULANI, FUL, PEUL, OR PHEUL), A NIGER-CONGO LANGUAGE SPOKEN THROUGHOUT THE GRASSLAND AREAS OF WEST AFRICA FROM THE ATLANTIC TO CAMEROUN. THE TEXT IS ONE OF A SERIES OF SHORT BASIC COURSES IN SELECTED AFRICAN LANGUAGES BEING PREPARED BY THE FOREIGN SERVICE INSTITUTE. IT IS…

  6. Basic Drafting: Book One.

    ERIC Educational Resources Information Center

    Davis, Ronald; And Others

    The first of a two-book course in drafting, this manual consists of 13 topics in the following units: introduction to drafting, general safety, basic tools and lines, major equipment, applying for a job, media, lettering, reproduction, drawing sheet layout, architect's scale usage, civil engineer's scale usage, mechanical engineer's scale usage,…

  7. Basic Drafting: Book Two.

    ERIC Educational Resources Information Center

    Davis, Ronald; And Others

    The second of a two-book course in drafting, this manual consists of 12 topics in the following units: sketching techniques, geometric constructions, orthographic views, dimensioning procedures, basic tolerancing, auxiliary views, sectional views, inking tools and techniques, axonometrics, oblique, perspective, and computer-aided drafting.…

  8. Czech Basic Course: Folklore.

    ERIC Educational Resources Information Center

    Defense Language Inst., Washington, DC.

    This booklet is designed for use in the advanced phase of the Defense Language Institute's "Basic Course" in Czech. It is used in the advanced phase as a part of cultural background information. Reading selections, with vocabulary lists, include: (1) ethnography; (2) incantations and spells; (3) proverbs, sayings, and weather lore; (4) fairy tales…

  9. Adult Basic Education Curriculum.

    ERIC Educational Resources Information Center

    Massachusetts Career Development Inst., Springfield.

    This booklet, aimed at adult basic education students, pinpoints and summarizes a few common spelling rules to help make spelling easier, and includes a component on using the dictionary. In the text, each rule is presented with many examples. Exercises follow each spelling rule, allowing students the opportunity to apply the rule to specific…

  10. Focus on Basics, 1998.

    ERIC Educational Resources Information Center

    Focus on Basics, 1998

    1998-01-01

    This volume contains the four 1998 quarterly issues of this newsletter that present best practices, current research on adult learning and literacy, and information on how research is used by adult basic education teachers, counselors, program administrators, and policy makers. The following are among the major articles included: "Power, Literacy,…