Repression of the hTERT gene during cell differentiation

细胞分化过程中 hTERT 基因的抑制

• 批准号: 6916309
• 负责人: JIYUE ZHU
• 金额: $ 25.95万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6916309
• 关键词: DNA binding protein; DNA footprinting; cell differentiation; cell line; chemical structure function; chromatin; chromatin immunoprecipitation; gene induction /repression; genetic regulatory element; genetic transcription; histones; posttranslational modifications; telomerase

DESCRIPTION (provided by applicant): Our long-term goal is to understand the critical steps of hTERT gene regulation during development. The hTERT gene, which encodes the rate-limiting subunit of human telomerase, is expressed at a high level in embryonic tissues and stem cells, but is repressed upon differentiation in the majority of adult somatic cells. Although the hTERT promoter has been studied extensively, the contribution of chromatin environment and the requirement of cis-elements have not been determined for the repression of the endogenous hTERT transcription. Previous results, including our own, have indicated that native chromatin plays a critical role in the regulation of hTERT transcription. hTERT transcription can be reversibly induced by inhibition of histone deacetylases and this induction is accompanied by chromatin remodeling at the hTERT promoter. Furthermore, we and others have shown that transiently transfected plasmid reporters are not ideal models for the repression of endogenous hTERT gene in somatic cells. Based on these findings, we hypothesize that chromatin environment is a critical component of the regulatory mechanisms for the repression of the native hTERT promoter. Here, we plan to study the molecular details of hTERT repression in a chromatin context using TPA-induced U937 cell differentiation as a model. We propose to pursue three interconnected aims: (1) To determine the role of global chromatin environment in hTERT repression during differentiation; (2) To determine sequential events of nuclear factor recruitment and histone modifications that occur at the hTERT core promoter region during differentiation. (3) To create a novel chromosome-based reporter system and dissect the roles of cis-regulatory elements in hTERT repression.

描述（由申请人提供）：我们的长期目标是了解开发过程中HTER基因调节的关键步骤。编码人端粒酶限速亚基的HTERT基因在胚胎组织和干细胞中以高水平表达，但在大多数成年体细胞中的分化时会受到抑制。 尽管已经对HTERT启动子进行了广泛的研究，但是尚未确定染色质环境的贡献和顺式元素的需求，以抑制内源性HTERT转录。 先前的结果，包括我们自己的结果，表明天然染色质在调节HTERT转录中起关键作用。 HTERT转录可以通过抑制组蛋白脱乙酰基酶可逆地诱导，并且这种诱导伴随着HTERT启动子的染色质重塑。 此外，我们和其他人已经表明，瞬时转染的质粒报道并不是抑制体细胞内源性HTERT基因的理想模型。基于这些发现，我们假设染色质环境是抑制天然HTERT启动子的调节机制的关键组成部分。在这里，我们计划使用TPA诱导的U937细胞分化作为模型来研究HTERT抑制的分子细节。我们建议追求三个相互联系的目标：（1）确定全球染色质环境在分化过程中的作用； （2）确定分化过程中HTERT核心启动子区域发生的核因子募集和组蛋白修饰的顺序事件。 （3）创建一种新型的基于染色体的报道器系统并剖析顺式调节元件在HTERT抑制中的作用。