Chromatin Remodeling During Liver Development

肝脏发育过程中的染色质重塑

• 批准号: 7645840
• 负责人: Lisa A Cirillo
• 金额: $ 26.6万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-10 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7645840
• 关键词: Address; Albumins; Binding; Binding Sites; Biochemical; Cell Differentiation process; Cells; Chromatin; Chromatin Structure; DNA Binding; Deoxyribonuclease I; Development; Diabetes Mellitus; Disease; Embryo; Endoderm; Enhancers; Environment; Enzymes; Event; Gene Activation; Genes; Genetic; Genetic Transcription; Goals; Grant; Growth and Development function; Hepatocyte; Histones; Human; In Vitro; Liver; Liver diseases; Malignant Neoplasms; Maps; Mediating; Metabolism; Modification; Molecular; Mutate; Mutation; Neoplasms; Nucleosomes; Play; Positioning Attribute; Procedures; Proteins; Regulator Genes; Research Design; Research Personnel; Role; Site; Specific qualifier value; System; Testing; Undifferentiated; chromatin remodeling; in vivo; insight; novel; reconstitution; research study; transcription factor

DESCRIPTION (provided by applicant): My goal is to determine how "pioneer" or initial chromatin binding transcription factors engage target sites in silent, compacted chromatin and promote entry of subsequent proteins. The pioneer transcription factor HNF3 binds to and activates numerous liver genes required for differentiation and metabolism. Previous studies have shown that HNF3 engages specific sites in chromatin in undifferentiated endoderm, prior to the activation of the albumin gene during liver specification. Using an in vitro system of reconstituted nucleosomes, I have demonstrated that HNF3 can bind its target sites within highly compacted chromatin packaging the albumin enhancer. This binding, and subsequent nucleosome positioning, creates a localized, open domain of chromatin accessible to other proteins. I hypothesize that chromatin binding and remodeling initiated by HNF3 establishes a chromatin environment that enables the subsequent binding, remodeling, and modification events required for albumin enhancer activation. I also propose that establishment of HNF3-mediated transcriptional competency is a prerequisite to the developmental activation of genes required for hepatocyte differentiation and function. In order to test these hypotheses, I will combine in vitro biochemical and in vivo-genetic approaches to address the following specific aims: 1) Does HNF3 displace linker histone from the albumin enhancer during chromatin opening? 2) Can HNF3-mediated chromatin remodeling activate the albumin enhancer in vivo? and 3) Is HNF3-mediated transcriptional competency essential for the activation of liver genes? These studies are designed to define the role played by pioneer DNA binding regulatory factors in the chromatin remodeling required for gene activation. Understanding how chromatin structural changes specify early gene regulatory events will provide insight into molecular mechanisms which underlie growth, development, and disease in humans. This primary goal of this grant is to determine the mechanisms used by the HNF3 protein to activate genes in the liver. HNF3 is essential for liver development, and is mutated in certain forms of cancer and diabetes. The results of the studies described in this grant will provide novel targets for the study and treatment of liver disease and neoplasia.

描述（由申请人提供）：我的目标是确定“先锋”或初始染色质结合转录因子如何在沉默的致密染色质中接合靶位点并促进后续蛋白质的进入。先驱转录因子HNF 3结合并激活分化和代谢所需的许多肝脏基因。先前的研究表明，HNF3在肝脏特化过程中白蛋白基因激活之前，与未分化内胚层染色质中的特定位点接合。使用体外系统的重建核小体，我已经证明，HNF3可以结合它的靶位点内高度压缩的染色质包装的白蛋白增强剂。这种结合和随后的核小体定位，产生了一个局部的，开放的染色质结构域，可供其他蛋白质使用。我推测，染色质结合和重塑启动HNF3建立染色质环境，使随后的结合，重塑，和白蛋白增强子激活所需的修饰事件。我还建议，建立HNF3介导的转录能力是一个先决条件，发展所需的肝细胞分化和功能的基因激活。为了验证这些假设，我将结合联合收割机在体外生物化学和体内遗传学的方法，以解决以下具体目标：1）是否HNF 3取代连接组蛋白从白蛋白增强在染色质开放？2)HNF3介导的染色质重塑能否在体内激活白蛋白增强子？3）HNF 3介导的转录能力对肝脏基因的激活是必需的吗？这些研究旨在确定先锋DNA结合调节因子在基因激活所需的染色质重塑中所起的作用。了解染色质结构变化如何指定早期基因调控事件将提供深入了解的分子机制，在人类的生长，发育和疾病的基础。 这项资助的主要目标是确定HNF3蛋白激活肝脏基因的机制。HNF3对肝脏发育至关重要，并在某些形式的癌症和糖尿病中发生突变。本资助中描述的研究结果将为肝脏疾病和肿瘤的研究和治疗提供新的靶点。