MECHANISM OF TRANSCRIPT ELONGATION IN CHROMATIN

染色质转录延伸的机制

• 批准号: 2731319
• 负责人: VASILY M STUDITSKY
• 金额: $ 21.85万
• 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 2002-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2731319
• 关键词: DNA directed RNA polymerase; DNA footprinting; acetylation; chromatin; cryoelectron microscopy; enzyme mechanism; enzyme structure; fungal genetics; genetic promoter element; genetic regulation; genetic transcription; nucleosomes; phosphorylation; posttranslational modifications; structural biology; transcription factor

The process of transcription is essential for all living cells. Transcription is composed of four steps: promoter binding, RNA chain initiation, RNA transcript elongation, and RNA transcript termination. Regulation of transcription can occur at each of these four steps. The long-term research goal of this proposal is to understand the mechanism and the regulation of transcript elongation by eukaryotic RNA polymerases. 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 transcription system in vitro. We will construct homogeneous and well-defined mono-and polynucleosomal chromatin templates. Transcription of these templates will be analyzed using biochemical and molecular genetic techniques, focusing on analysis of eukaryotic RNA polymerases. The specific aims are: (1) To ascertain the mechanism determining the rate of transcription through chromatin by RNA polymerases II and III. Information to be obtained here will provide structural framework for understanding of transcription through chromatin and its rate-limiting step(s). (2) To ascertain the effect of specific elongation factors, modifications of chromatin structure, and modifications of RNA pol II on the rate of 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 oncogeneses underscores the potential clinical significance of analysis of the mechanism of transcript elongation.

转录过程对所有活细胞都是必不可少的。 转录由四个步骤组成：启动子结合，RNA链 起始、RNA转录物延伸和RNA转录物终止。 转录调控可以发生在这四个步骤中的每一个。的 长期研究的目标是了解这一建议的机制 以及真核RNA聚合酶对转录物延伸的调节。 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， 通过RNA聚合酶的高效转录。然而，对于许多基因来说， 是转录区域被核小体覆盖的证据这 提出了一些问题： (1)聚合酶如何通过染色质屏障转录？ (2)屏障能改变转录延长的速率吗？ 这些问题将在体外转录系统中得到解决。我们 将构建均匀且定义明确的单核和多核小体 染色质模板将分析这些模板的转录 利用生物化学和分子遗传学技术， 真核生物RNA聚合酶。具体目标是： (1)确定转录速率的机制 通过RNA聚合酶II和III通过染色质。信息 这里获得的将提供结构框架的理解 通过染色质及其限速步骤的转录。 (2)为了确定比延伸系数的影响， 染色质结构的变化，以及RNA聚合酶II的修饰对染色质结构的影响。 通过染色质转录。这些实验将导致更好的 从转录水平理解转录调控 伸长率 发现一些延伸因子在 致癌基因的分析强调了潜在的临床意义， 转录延长的机制。