Sox Proteins Modulate Genomic Specificity of B-catenin Regulated Transcription in the Developing Gut

Sox 蛋白调节发育中肠道中 B-连环蛋白调节转录的基因组特异性

• 批准号: 10540791
• 负责人: Aaron M Zorn
• 金额: $ 55.71万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10540791
• 关键词: ATAC-seq; Binding; Binding Proteins; Binding Sites; Biochemical; Biological; Biological Assay; Cell Nucleus; Cells; ChIP-seq; Chromatin; Complex; Computer Analysis; Consensus; Coupled; Cytoplasm; DNA; DNA Binding; Data; Data Set; Development; Disease; Embryo; Endoderm; Enhancers; Epigenetic Process; Gene Expression; Genes; Genetic; Genetic Epistasis; Genetic Transcription; Genomic approach; Genomics; Growth Factor; HMG-Box Domains; Hindgut; Histones; Homeostasis; Human; In Vitro; Logic; Malignant Neoplasms; Mediating; Modeling; Molecular; Mutation Analysis; Pathway interactions; Primitive foregut structure; Proteins; Publishing; Recombinants; Regulation; Reporter; Reporting; Repression; Role; SOX17 gene; Site; Specific qualifier value; Specificity; Systems Development; Testing; Therapeutic; Tissues; WNT Signaling Pathway; Xenopus; beta catenin; candidate identification; cell type; cofactor; experimental study; gastrointestinal system; gene repression; genetic corepressor; genome-wide; human pluripotent stem cell; in vivo; novel; progenitor; programs; recruit; response; stem cell homeostasis; therapeutic target; transcription factor; transcriptome sequencing

PROJECT SUMMARY/ABSTRACT This proposal will test the hypothesis that SOX transcription factors (TFs) modulate the genomic specificity of Wnt/Beta-catenin (BCAT) mediated transcription in early gut development and determine the underlying molecular mechanisms. Wnt signaling regulates gene expression in digestive system development, homeostasis and disease, where it is an important therapeutic target. While the core Wnt transcriptional machinery is well studied, how cell-specific target genes are selected remains one of the most important unresolved issues in the field. Current dogma is that canonical Wnt stabilizes cytoplasmic BCAT, which translocates to the nucleus and interacts with one of four TCF/LEF HMG-box TFs to stimulate transcription. However, all TCFs bind to nearly identical consensus sites indicating they alone cannot account for the diversity of transcriptional responses. Using the complementary advantages of Xenopus embryos and differentiating human pluripotent stem cells (hPSC), we have accumulated compelling evidence that SOX HMG-box TFs modulate the genomic specificity of Wnt/BCAT-mediated transcription during early gut development. Our preliminary ChIP-seq data and functional analyses suggests that different SOX TFs can recruit BCAT to distinct enhancers in a tissue specific manner. On some enhancers SOX and BCAT synergistically activate transcription independent of TCFs. Other enhancers appear to be co-occupied by SOX, BCAT and TCFs, suggesting tertiary complexes where SOX and TCF might cooperate or compete to bind DNA and BCAT to activate or represses transcription. These data suggest novel regulatory mechanisms and indicate that SOXs may be wide-spread unappreciated factors regulating Wnt responses. We propose to test this hypothesis with the following aims: Aim 1: Test the hypothesis that SOXs regulate the genomic recruitment of BCAT to lineage specific enhancers. Aim 2: Determine how Sox17 and Bcat coregulate Wnt-responsive enhancers to control spatially restricted transcription in the embryo. Aim 3: Determine the biochemical mechanisms by which SOX-BCAT-TCF complexes interact on DNA. These studies will reveal the SOX-BCAT regulated GRN of gut development and provide a new paradigm for how cell-specific Wnt-mediated transcription is regulated in development and disease.

项目摘要/摘要 这项提议将检验SOX转录因子(TF)调节基因组的假设 Wnt/Beta-Catenin(BCAT)介导的转录在肠道早期发育中的特异性及其确定 潜在的分子机制。WNT信号调节消化系统基因表达 发展、动态平衡和疾病，在这些领域，它是一个重要的治疗目标。而核心WNT 转录机制已经得到了很好的研究，但如何选择细胞特有的靶基因仍然是最重要的研究之一。 该领域中尚未解决的重要问题。目前的教条是，规范的Wnt稳定细胞质BCAT，这是 转位到细胞核，并与四种Tcf/Lef HMG-box Tf中的一种相互作用以刺激转录。 然而，所有的TCF都与几乎相同的共识位点相结合，这表明它们本身不能解释多样性 转录反应。利用非洲爪哇胚胎的互补优势和分化 人类多能干细胞(HPSC)，我们已经积累了令人信服的证据表明Sox HMG-box TF 在肠道发育早期调节Wnt/BCAT介导的转录的基因组特异性。我们的 初步的CHIP-SEQ数据和功能分析表明，不同的SOX转录因子可以招募BCAT来区分 以组织特异性方式的增强剂。某些促进剂SOX和BCAT协同激活转录 独立于TCFs。其他增强剂似乎被SOX、BCAT和TCFs共同占据，这表明第三 SOX和TCF可能合作或竞争结合DNA和BCAT以激活或抑制的复合体 抄写。这些数据表明了新的调控机制，并表明SOX可能会广泛传播 未被认可的调节WNT反应的因素。我们建议通过以下目标来检验这一假设： 目的1：验证SOXS调节BCAT向谱系特异性增强子的基因组募集的假设。 目标2：确定Sox17和BCAT如何共同调节Wnt反应增强子以控制空间受限 胚胎中的转录。 目的3：确定SOX-BCAT-TCF复合体与DNA相互作用的生化机制。 这些研究将揭示SOX-BCAT调控的肠道发育GRN，并提供一个新的范式 了解细胞特异性Wnt介导的转录在发育和疾病中是如何调控的。