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Results for “Gene Expression Regulation, Developmental”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Brg1 modulates enhancer activation in mesoderm lineage commitment

The interplay between different levels of gene regulation in modulating developmental transcriptional programs, such as histone modifications and chromatin remodeling, is not well understood. Here, we show that the chromatin remodeling factor Brg1 is required for enhancer activation in mesoderm induction. In an embryonic stem cell-based directed differentiation assay, the absence of Brg1 results in a failure of cardiomyocyte differentiation and broad deregulation of lineage-specific gene expression during mesoderm induction. We find that Brg1 co-localizes with H3K27ac at distal enhancers and is required for robust H3K27 acetylation at distal enhancers that are activated during mesoderm induction. Brg1 is also required to maintain Polycomb-mediated repression of non-mesodermal developmental regulators, suggesting cooperativity between Brg1 and Polycomb complexes. Thus, Brg1 is essential for modulating active and repressive chromatin states during mesoderm lineage commitment, in particular the activation of developmentally important enhancers. In conclusion, these findings demonstrate interplay between chromatin remodeling complexes and histone modifications that, together, ensure robust and broad gene regulation during crucial lineage commitment decisions.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Developmentally regulated GTP-binding protein 2 depletion leads to mitochondrial dysfunction through downregulation of dynamin-related protein 1

Mitochondrial dynamics, including constant fusion and fission, play critical roles in maintaining mitochondrial morphology and function. Here, we report that developmentally regulated GTP-binding protein 2 (DRG2) regulates mitochondrial morphology by modulating the expression of the mitochondrial fission gene dynamin-related protein 1 (Drp1). shRNA-mediated silencing of DRG2 induced mitochondrial swelling, whereas expression of an shRNA-resistant version of DRG2 decreased mitochondrial swelling in DRG2-depleted cells. Analysis of the expression levels of genes involved in mitochondrial fusion and fission revealed that DRG2 depletion significantly decreased the level of Drp1. Overexpression of Drp1 rescued the defect in mitochondrial morphology induced by DRG2 depletion. DRG2 depletion reduced the mitochondrial membrane potential, oxygen consumption rate (OCR), and amount of mitochondrial DNA (mtDNA), whereas it increased reactive oxygen species (ROS) production and apoptosis. Taken together, our data demonstrate that DRG2 acts as a regulator of mitochondrial fission by controlling the expression of Drp1. - Highlights: • DRG2 depletion increased mitochondrial swelling. • DRG2 depletion inhibited the expression of Drp1. • Overexpression of DRG2 or Drp1 rescued mitochondrial shape in DRG2 depleted cells. • DRG2 depletion induced mitochondrial dysfunction.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

A Systems Biology Approach to Identify Essential Epigenetic Regulators for Specific Biological Processes in Plants

Upon sensing developmental or environmental cues, epigenetic regulators transform the chromatin landscape of a network of genes to modulate their expression and dictate adequate cellular and organismal responses. Knowledge of the specific biological processes and genomic loci controlled by each epigenetic regulator will greatly advance our understanding of epigenetic regulation in plants. To facilitate hypothesis generation and testing in this domain, we present EpiNet, an extensive gene regulatory network (GRN) featuring epigenetic regulators. EpiNet was enabled by (i) curated knowledge of epigenetic regulators involved in DNA methylation, histone modification, chromatin remodeling, and siRNA pathways; and (ii) a machine-learning network inference approach powered by a wealth of public transcriptome datasets. We applied GENIE3, a machine-learning network inference approach, to mine public Arabidopsis transcriptomes and construct tissue-specific GRNs with both epigenetic regulators and transcription factors as predictors. The resultant GRNs, named EpiNet, can now be intersected with individual transcriptomic studies on biological processes of interest to identify the most influential epigenetic regulators, as well as predicted gene targets of the epigenetic regulators. We demonstrate the validity of this approach using case studies of shoot and root apical meristem development.

root apical meristem↗
NASA NTRS1992

Identification of a mouse B-type cyclin which exhibits developmentally regulated expression in the germ line

To begin to examine the function of cyclins in mammalian germ cells, we have screened an adult mouse testis cDNA library for the presence of B-type cyclins. We have isolated cDNAs that encode a murine B-type cyclin, which has been designated cycB1. cycB1 was shown to be expressed in several adult tissues and in the midgestation mouse embryo. In the adult tissues, the highest levels of cycB1 transcripts were seen in the testis and ovary, which contain germ cells at various stages of differentiation. The major transcripts corresponding to cycB1 are 1.7 and 2.5 kb, with the 1.7 kb species being the predominant testicular transcript and the 2.5 kb species more abundant in the ovary. Examination of cDNAs corresponding to the 2.5 kb and 1.7 kb mRNAs revealed that these transcripts encode identical proteins, differing only in the polyadenylation signal used and therefore in the length of their 3' untranslated regions. Northern blot and in situ hybridization analyses revealed that the predominant sites of cycB1 expression in the testis and ovary were in the germinal compartment, particularly in early round spermatids in the testis and growing oocytes in the ovary. Thus cycB1 is expressed in both meiotic and postmeiotic cells. This pattern of cycB1 expression further suggests that cycB1 may have different functions in the two cell types, only one of which correlates with progression of the cell cycle.

NASA Discipline Developmental Biology↗
NASA NTRS1995

Arabidopsis TCH4, regulated by hormones and the environment, encodes a xyloglucan endotransglycosylase

Adaptation of plants to environmental conditions requires that sensing of external stimuli be linked to mechanisms of morphogenesis. The Arabidopsis TCH (for touch) genes are rapidly upregulated in expression in response to environmental stimuli, but a connection between this molecular response and developmental alterations has not been established. We identified TCH4 as a xyloglucan endotransglycosylase by sequence similarity and enzyme activity. Xyloglucan endotransglycosylases most likely modify cell walls, a fundamental determinant of plant form. We determined that TCH4 expression is regulated by auxin and brassinosteroids, by environmental stimuli, and during development, by a 1-kb region. Expression was restricted to expanding tissues and organs that undergo cell wall modification. Regulation of genes encoding cell wall-modifying enzymes, such as TCH4, may underlie plant morphogenetic responses to the environment.

NASA Discipline Plant Biology↗
DOE OSTI2021

Transcription initiation as a control point in plastid gene expression

The extensive processing and protein-assisted stabilization of transcripts have been taken as evidence for a viewpoint that the control of gene expression had shifted entirely in evolution from transcriptional in the bacterial endosymbiont to posttranscriptional in the plastid. This suggestion is however at odds with many observations on plastid gene transcription. Chloroplasts of flowering plants and mosses contain two or more RNA polymerases with distinct promoter preference and division of labor for the coordinated synthesis of plastid RNAs. Plant and algal plastids further possess multiple nonredundant sigma factors that function as transcription initiation factors. The controlled accumulation of plastid sigma factors and modification of their activity by sigma-binding proteins and phosphorylation constitute additional transcriptional regulatory strategies. Plant and algal plastids also contain dedicated one- or two-component transcriptional regulators. Finally, transcription initiation thus continues to form a critical control point at which varied developmental and environmental signals intersect with plastid gene expression.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Nr2f1 enhancers have distinct functions in controlling Nr2f1 expression during cortical development

There is evidence that transcription factor (TF) encoding genes, which temporally control development in multiple cell types, can have tens of enhancers that regulate their expression. The NR2F1 TF developmentally promotes caudal and ventral cortical regional fates. Here, we epigenomically compared the activity of Nr2f1’s enhancers during mouse cortical development with their activity in a transgenic assay. We identified at least six that are likely to be important in prenatal cortical development, with three harboring de novo mutants identified in ASD individuals. We chose to study the function of two of the most robust enhancers by deleting them singly or together. We found that they have distinct and overlapping functions in driving Nr2f1’s regional and laminar expression in the developing cortex. Thus, these two enhancers, probably in combination with the others that we defined epigenetically, precisely tune Nr2f1’s regional, cell type, and temporal expression during corticogenesis.

Liu, Zhidong↗
DOE OSTI2015

Del-1 overexpression potentiates lung cancer cell proliferation and invasion

Developmental endothelial locus-1 (Del-1) is an endogenous anti-inflammatory molecule that is highly expressed in the lung and the brain and limits leukocyte migration to these tissues. We previously reported that the expression of Del-1 is positively regulated by p53 in lung endothelial cells. Although several reports have implicated the altered expression of Del-1 gene in cancer patients, little is known about its role in tumor cells. We here investigated the effect of Del-1 on the features of human lung carcinoma cells. Del-1 mRNA was found to be significantly decreased in the human lung adenocarcinoma cell lines A549 (containing wild type of p53), H1299 (null for p53) and EKVX (mutant p53), compared to in human normal lung epithelial BEAS-2B cells and MRC-5 fibroblasts. The decrease of Del-1 expression was dependent on the p53 activity in the cell lines, but not on the expression of p53. Neither treatment with recombinant human Del-1 protein nor the introduction of adenovirus expressing Del-1 altered the expression of the apoptosis regulators BAX, PUMA and Bcl-2. Unexpectedly, the adenovirus-mediated overexpression of Del-1 gene into the lung carcinoma cell lines promoted proliferation and invasion of the lung carcinoma cells, as revealed by BrdU incorporation and transwell invasion assays, respectively. In addition, overexpression of the Del-1 gene enhanced features of epithelial–mesenchymal transition (EMT), such as increasing vimentin while decreasing E-cadherin in A549 cells, and increases in the level of Slug, an EMT-associated transcription regulator. Our findings demonstrated for the first time that there are deleterious effects of high levels of Del-1 in lung carcinoma cells, and suggest that Del-1 may be used as a diagnostic or prognostic marker for cancer progression, and as a novel therapeutic target for lung carcinoma. - Highlights: • Developmental Endothelial Locus-1 (Del-1) expression is downregulated in human lung cancer cells. • Overexpression of the Del-1 gene potentiates proliferation and invasion of lung carcinoma cells. • Del-1 may be used as a diagnostic or prognostic marker for lung cancer progression.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

Dynamics of Global Gene Expression and Regulatory Elements in Growing Brachypodium Root System

Root systems are dynamic and adaptable organs that play critical roles in plant development. However, how roots grow and accumulate biomass during plant life cycle and in relation to shoot growth phenology remains understudied. A comprehensive time-dependent root morphological analysis integrated with molecular signatures is then required to advance our understanding of root growth and development. Here we studied Brachypodium distachyon rooting process by monitoring root morphology, biomass production, and C/N ratios during developmental stages. To provide insight into gene regulation that accompanies root growth, we generated comprehensive transcript profiles of Brachypodium whole-root system at four developmental stages. Our data analysis revealed that multiple biological processes including trehalose metabolism and various families of transcription factors (TFs) were differentially expressed in root system during plant development. In particular, the AUX/IAA, ERFs, WRKY, NAC, and MADS TF family members were upregulated as plant entered the booting/heading stage, while ARFs and GRFs were downregulated suggesting these TF families as important factors involved in specific phases of rooting, and possibly in regulation of transition to plant reproductive stages. We identified several Brachypodium candidate root biomass-promoting genes and cis -regulatory elements for further functional validations and root growth improvements in grasses.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1999

Myosin Heavy Chain Gene Expression in Developing Neonatal Skeletal Muscle: Involvement of the Nerve, Gravity, and Thyroid State

The myosin heavy chain (MHC) gene family encodes at least six MHC proteins (herein designated as neonatal, embryonic, slow type I (beta), and fast IIa, IIx, and IIb) that are expressed in skeletal muscle in a muscle-specific and developmentally-regulated fashion. At birth, both antigravity (e.g. soleus) and locomotor (e.g., plantaris) skeletal muscles are undifferentiated relative to the adult MHC phenotype such that the neonatal and embryonic MHC isoforms account for 80 - 90% of the MHC pool in a fast locomotor muscle; whereas, the embryonic and slow, type I isoforms account for approx. 90% of the pool in a typical antigravity muscle. The goal of this study was to investigate the role of an intact nerve, gravity and thyroid hormone (T3), as well as certain interactions of these interventions, on MHC gene expression in developing neonatal skeletal muscles of rodents.

Baldwin, K. M.↗
DOE OSTI2015

A dynamic intron retention program enriched in RNA processing genes regulates gene expression during terminal erythropoiesis

Differentiating erythroblasts execute a dynamic alternative splicing program shown here to include extensive and diverse intron retention (IR) events. Cluster analysis revealed hundreds of developmentallydynamic introns that exhibit increased IR in mature erythroblasts, and are enriched in functions related to RNA processing such as SF3B1 spliceosomal factor. Distinct, developmentally-stable IR clusters are enriched in metal-ion binding functions and include mitoferrin genes SLC25A37 and SLC25A28 that are critical for iron homeostasis. Some IR transcripts are abundant, e.g. comprising ~50% of highly-expressed SLC25A37 and SF3B1 transcripts in late erythroblasts, and thereby limiting functional mRNA levels. IR transcripts tested were predominantly nuclearlocalized. Splice site strength correlated with IR among stable but not dynamic intron clusters, indicating distinct regulation of dynamically-increased IR in late erythroblasts. Retained introns were preferentially associated with alternative exons with premature termination codons (PTCs). High IR was observed in disease-causing genes including SF3B1 and the RNA binding protein FUS. Comparative studies demonstrated that the intron retention program in erythroblasts shares features with other tissues but ultimately is unique to erythropoiesis. Finally, we conclude that IR is a multi-dimensional set of processes that post-transcriptionally regulate diverse gene groups during normal erythropoiesis, misregulation of which could be responsible for human disease.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1992

Glucocorticoids promote development of the osteoblast phenotype by selectively modulating expression of cell growth and differentiation associated genes

To understand the mechanisms by which glucocorticoids promote differentiation of fetal rat calvaria derived osteoblasts to produce bone-like mineralized nodules in vitro, a panel of osteoblast growth and differentiation related genes that characterize development of the osteoblast phenotype has been quantitated in glucocorticoid-treated cultures. We compared the mRNA levels of osteoblast expressed genes in control cultures of subcultivated cells where nodule formation is diminished, to cells continuously (35 days) exposed to 10(-7) M dexamethasone, a synthetic glucocorticoid, which promotes nodule formation to levels usually the extent observed in primary cultures. Tritiated thymidine labelling revealed a selective inhibition of internodule cell proliferation and promotion of proliferation and differentiation of cells forming bone nodules. Fibronectin, osteopontin, and c-fos expression were increased in the nodule forming period. Alkaline phosphatase and type I collagen expression were initially inhibited in proliferating cells, then increased after nodule formation to support further growth and mineralization of the nodule. Expression of osteocalcin was 1,000-fold elevated in glucocorticoid-differentiated cultures in relation to nodule formation. Collagenase gene expression was also greater than controls (fivefold) with the highest levels observed in mature cultures (day 35). At this time, a rise in collagen and TGF beta was also observed suggesting turnover of the matrix. Short term (48 h) effects of glucocorticoid on histone H4 (reflecting cell proliferation), alkaline phosphatase, osteopontin, and osteocalcin mRNA levels reveal both up or down regulation as a function of the developmental stage of the osteoblast phenotype. A comparison of transcriptional levels of these genes by nuclear run-on assays to mRNA levels indicates that glucocorticoids exert both transcriptional and post-transcriptional effects. Further, the presence of glucocorticoids enhances the vitamin D3 effect on gene expression. Those genes which are upregulated by 1,25(OH)2D3 are transcribed at an increased rate by dexamethasone, while those genes which are inhibited by vitamin D3 remain inhibited in the presence of dexamethasone and D3. We propose that the glucocorticoids promote changes in gene expression involved in cell-cell and cell-extracellular matrix signaling mechanisms that support the growth and differentiation of cells capable of osteoblast phenotype development and bone tissue-like organization, while inhibiting the growth of cells that cannot progress to the mature osteoblast phenotype in fetal rat calvarial cultures.

NASA Discipline Musculoskeletal↗
DOE OSTI2018

Exploring parasite heterogeneity using single-cell RNA-seq reveals a gene signature among sexual stage Plasmodium falciparum parasites

The malaria parasite has a complex lifecycle, including several events of differentiation and stage progression, while actively evading immunity in both its mosquito and human hosts. Important parasite gene expression and regulation during these events remain hidden in rare populations of cells. Here, we combine a capillary-based platform for cell isolation with single-cell RNA-sequencing to transcriptionally profile 165 single infected red blood cells (iRBCs) during the intra-erythrocytic developmental cycle (IDC). Unbiased analyses of single-cell data grouped the cells into eight transcriptional states during IDC. Interestingly, we uncovered a gene signature from the single iRBC analyses that can successfully discriminate between developing asexual and sexual stage parasites at cellular resolution, and we verify five, previously undefined, gametocyte stage specific genes. Moreover, we show the capacity of detecting expressed genes from the variable gene families in single parasites, despite the sparse nature of data. In total, the single parasite transcriptomics holds promise for molecular dissection of rare parasite phenotypes throughout the malaria lifecycle.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1993

HSP86 and HSP84 exhibit cellular specificity of expression and co-precipitate with an HSP70 family member in the murine testis

This study extends to the protein level our previous observations, which had established the stage and cellular specificity of expression of hsp86 and hsp84 in the murine testis in the absence of exogenous stress. Immunoblot analysis was used to demonstrate that HSP86 protein was present throughout testicular development and that its levels increased with the appearance of differentiating germ cells. HSP86 was most abundant in the germ cell population and was present at significantly lower levels in the somatic cells. By contrast, the HSP84 protein was detected in the somatic cells of the testis rather than in germ cells. The steady-state levels of HSP86 and HSP84 paralleled the pattern of the expression of their respective mRNAs, suggesting that regulation at the level of translation was not a major mechanism controlling hsp90 gene expression in testicular cells. Immunoprecipitation analysis revealed that a 70-kDa protein coprecipitated with the HSP86/HSP84 proteins in testicular homogenates. This protein was identified as an HSP70 family member by immunoblot analysis, suggesting that HSP70 and HSP90 family members interact in testicular cells.

NASA Discipline Number 40-20↗
DOE OSTI2022

Concentration-response gene expression analysis in zebrafish reveals phenotypically-anchored transcriptional responses to retene

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants and are associated with human disease. Canonically, many PAHs induce toxicity via activation of the aryl hydrocarbon receptor (AHR) pathway. While the interaction between PAHs and the AHR is well-established, understanding which AHR-regulated transcriptional effects directly result in observable phenotypes and which are adaptive or benign is important to better understand PAH toxicity. Retene is a frequently detected PAH in environmental sampling and has been associated with AHR2-dependent developmental toxicity in zebrafish, though its mechanism of toxicity has not been fully elucidated. To interrogate transcriptional changes causally associated with retene toxicity, we conducted whole-animal RNA sequencing at 48 hours post-fertilization after exposure to eight retene concentrations. The concentrations were selected to produce effects ranging from no phenotype to mortality and malformations in 100% of animals at 5 days post-fertilization. We identified a concentration-response relationship between retene teratogenicity and differential gene expression in both number of DEGs and magnitude of expression change. Elevated expression of cyp1a at retene concentrations below the threshold for teratogenicity suggested that while cyp1a expression is a sensitive biomarker of AHR activation, it may be too sensitive to serve as a biomarker of AHR-dependent teratogenicity. Genes differentially expressed at only non-teratogenic concentrations were enriched for transforming growth factor-ß (TGF-ß) signaling pathway disruption while DEGs identified at only teratogenic concentrations were significantly enriched for response to xenobiotic stimulus and reduction-oxidation reaction activity. DEGs which spanned both non-teratogenic and teratogenic concentrations showed similar disrupted biological processes to those unique to teratogenic concentrations, indicating these processes were disrupted at low exposure concentrations. Gene co-expression network analysis identified several gene modules, including those associated with PAHs and AHR2 activation. One, Module 7, was strongly enriched for AHR2-associated genes and contained the strongest responses to retene. Benchmark concentration (BMC) of Module 7 genes identified a median BMC of 7.5 µM, nearly the highest retene concentration with no associated teratogenicity, supporting the hypothesis that Module 7 genes are largely responsible for retene toxicity.

Toxin, Zebrafish, Retene, Transcriptomics, network↗
DOE OSTI2026

Gene and genome duplications have contrasting impacts on biosynthetic and flower developmental pathways in California poppy

Benzylisoquinoline alkaloids (BIAs) represent a vast group of specialized plant metabolites with diverse pharmaceutical applications, synthesized by a variety of gene families. Among the multiple plant lineages that produce BIAs, the most notable is the poppy family (Papaveraceae), with California poppy (Eschscholzia californica) emerging as a model organism. Here, we report a haplotype-resolved genome assembly, in combination with a high-density expression atlas, for California poppy. Genome analyses reveal recent diversification of BIA biosynthesis genes in poppy through localized duplications. Furthermore, we demonstrate that the degree of phylogenetic relatedness among paralogs within BIA biosynthesis-associated gene families correlates with similarities in gene expression. In contrast, gene families involved in carotenoid biosynthesis, which contributes to the intense orange petal pigmentation, are not phylogenetically clustered, and floral developmental regulators exhibit a high degree of retention of gene duplicates associated with ancient polyploidy events. These findings illustrate alternative roles for gene and genome duplications as drivers of trait evolution. Given the position of California poppy in the angiosperm phylogeny, the high-quality genomic resources generated for this work constitute a valuable resource for comparative genomic and transcriptomic analyses for poppies and flowering plants more generally.

Rössner, Le-Han [Justus-Liebig University, Giessen↗
DOE OSTI2019

Comparative Transcriptomics Analyses across Species, Organs, and Developmental Stages Reveal Functionally Constrained lncRNAs

The functionality of long noncoding RNAs (lncRNAs) is disputed. In general, lncRNAs are under weak selective pressures, suggesting that the majority of lncRNAs may be nonfunctional. However, although some surveys showed negligible phenotypic effects upon lncRNA perturbation, key biological roles were demonstrated for individual lncRNAs. Most lncRNAs with proven functions were implicated in gene expression regulation, in pathways related to cellular pluripotency, differentiation, and organ morphogenesis, suggesting that functional lncRNAs may be more abundant in embryonic development, rather than in adult organs. To test this hypothesis, we perform a multidimensional comparative transcriptomics analysis, across five developmental time points (two embryonic stages, newborn, adult, and aged individuals), four organs (brain, kidney, liver, and testes), and three species (mouse, rat, and chicken). We find that, overwhelmingly, lncRNAs are preferentially expressed in adult and aged testes, consistent with the presence of permissive transcription during spermatogenesis. LncRNAs are often differentially expressed among developmental stages and are less abundant in embryos and newborns compared with adult individuals, in agreement with a requirement for tighter expression control and less tolerance for noisy transcription early in development. For differentially expressed lncRNAs, we find that the patterns of expression variation among developmental stages are generally conserved between mouse and rat. Moreover, lncRNAs expressed above noise levels in somatic organs and during development show higher evolutionary conservation, in particular, at their promoter regions. Thus, we show that functionally constrained lncRNA loci are enriched in developing organs, and we suggest that many of these loci may function in an RNA-independent manner.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

In vitro analysis of the transcriptional regulatory mechanism of zebrafish pou5f3

Highlights: • The zebrafish PouV gene, pou5f3, is regulated by an autoregulatory loop. • Pou5f3 activates transcription synergistically with Sox3. • Functional subregions were identified in Pou5f3 regarding its regulatory activities. • The functional synergy of Pou5f3 with SoxB1 is unique among POU factors. Zebrafish pou5f3 (previously named pou2), a close homologue of mouse Oct4, encodes a PouV-family transcription factor. pou5f3 has been implicated in diverse aspects of developmental regulation during embryogenesis. In the present study, we addressed the molecular function of Pou5f3 as a transcriptional regulator and the mechanism by which pou5f3 expression is transcriptionally regulated. We examined the influence of effector genes on the expression of the luciferase gene under the control of the upstream 2.1-kb regulatory DNA of pou5f3 (Luc-2.2) in HEK293T and P19 cells. We first confirmed that Pou5f3 functions as a transcriptional activator both in cultured cells and embryos, which confirmed autoregulation of pou5f3 in embryos. It was further shown that Luc-2.2 was activated synergistically by pou5f3 and sox3, which is similar to the co-operative activity of Oct4 and Sox2 in mice, although synergy between pou5f3 and sox2 was less obvious in this zebrafish system. The effects of pou5f3 deletion constructs on the regulation of Luc-2.2 expression revealed different roles for the three subregions of the N-terminal region in Pou5f3 in terms of its regulatory functions and co-operativity with Sox3. Electrophoretic mobility shift assays confirmed that Pou5f3 and Sox3 proteins specifically bind to adjacent sites in the 2.1-kb DNA and that there is an interaction between the two proteins. The synergy with sox3 was unique to pou5f3—the other POU factor genes examined did not show such synergy in Luc-2.2 regulation. Finally, functional interaction was observed between pou5f3 and sox3 in embryos in terms of the regulation of dorsoventral patterning and convergent extension movement. These findings together demonstrate co-operative functions of pou5f3 and sox3, which are frequently coexpressed in early embryos, in the regulation of early development.

60 APPLIED LIFE SCIENCES↗