MECHANISM OF TRANSCRIPT ELONGATION IN CHROMATIN

染色质转录延伸的机制

• 批准号: 6580887
• 负责人: VASILY M STUDITSKY
• 金额: $ 11.96万
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2003-08-21
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6580887
• 关键词: DNA directed RNA polymerase; HeLa cells; acetylation; chromatin; electron microscopy; enzyme mechanism; fluorescence resonance energy transfer; gene expression; genetic transcription; histones; molecular genetics; nucleosomes; phosphorylation; transcription factor; translation factor

DESCRIPTION (provided by applicant): The process of transcription is essential for all living cells. Transcription is accomplished in four steps: promoter binding, RNA chain initiation, RNA transcript elongation, and RNA transcript termination. Regulation of transcription can occur at each of these steps. The long-term research goal of this proposal is to understand the mechanism and the regulation of transcript elongation by eukaryotic RNA polymerases in chromatin. When eukaryotic genes are activated for transcription, their chromatin structure changes to accommodate transcription factors and to allow efficient transcription by RNA polymerases. However, for many genes there is evidence that transcribed regions are covered with nucleosomes. This raises the questions: 1. How do polymerases transcribe through the chromatin barrier? 2. Can the barrier change the rate of transcript elongation? These questions will be addressed in a highly purified transcription system in vitro. We will analyze transcription of homogeneous and well-defined mono- and polynucleosomal chromatin templates using biochemical and molecular genetic techniques, focusing on analysis of eukaryotic RNA polymerase II. The specific aims are: 1. To ascertain the mechanism of transcription through chromatin by RNA polymerase II: the fate of the histone octamer and the nature of nucleosomal barrier to transcription. Information to be obtained here will provide a structural framework for understanding of transcription through chromatin and its rate-limiting step(s). 2. To ascertain the rote of elongation factors, modifications of chromatin structure, and modifications of RNA polymerase II in facilitating transcription through chromatin. These experiments will lead to better understanding of regulation of transcription at the level of transcript elongation. The discovery that some elongation factors play important roles in oncogenesis underscores the potential clinical significance of analysis of the mechanism of transcript elongation.

描述（由申请人提供）：转录过程对所有活细胞都是必不可少的。转录通过四个步骤完成：启动子结合、RNA链起始、RNA转录延伸和RNA转录终止。转录调控可以发生在这些步骤中的每一步。本课题的长期研究目标是了解真核RNA聚合酶在染色质中转录延伸的机制和调控。当真核基因被激活转录时，它们的染色质结构改变以适应转录因子并允许RNA聚合酶有效转录。然而，有证据表明，许多基因的转录区被核小体覆盖。这就提出了以下问题：1。聚合酶如何通过染色质屏障进行转录？2. 屏障能改变转录物延伸率吗？这些问题将在体外高度纯化的转录系统中得到解决。我们将使用生化和分子遗传学技术分析均匀和定义良好的单核体和多核体染色质模板的转录，重点分析真核RNA聚合酶II。具体目标是：1。确定RNA聚合酶II通过染色质进行转录的机制：组蛋白八聚体的命运和核小体转录屏障的性质。在这里获得的信息将为理解通过染色质及其限速步骤的转录提供一个结构框架。2. 确定延长因子、染色质结构修饰和RNA聚合酶II修饰在促进染色质转录中的作用。这些实验将有助于更好地理解转录延伸水平上的转录调控。一些延伸因子在肿瘤发生中发挥重要作用的发现，强调了分析转录物延伸机制的潜在临床意义。