Chromatin replication control by protein ubiquitylation

 描述(由申请人提供)：该研究计划的长期目标是为蛋白质泛素化如何在DNA复制过程中调节染色质动态产生范例。最近的证据表明，蛋白质泛素化系统的组成部分直接和机械地参与了许多重要的生物学过程，如基因激活(包括共激活因子招募、共转录mRNA处理和转录终止)、DNA损伤修复和DNA复制。然而，起作用的潜在分子机制仍然不清楚。为了了解泛素(Ub)和Ub连接酶影响染色质介导的生物过程的基本方式，该项目重点揭示了组蛋白泛素化事件如何调节染色质结构，DNA聚合酶如何受到Ub介导的核小体动力学的调控。这些研究利用化学合成的携带位点特异性Ub的组蛋白，并使用尖端的生化和基因组方法来确定通过蛋白质泛素化来控制转录和复制的机制和意义。这些研究的结果将在两个主要领域产生广泛影响。首先，他们将阐明DNA复制的一个鲜为人知的方面。直到最近人们才意识到泛素化直接参与复制，尽管这是一个快速发展的领域，但一般主题和过程尚未确定。这些研究将定义这些一般主题，并通过这样做揭示调控DNA复制的新方式。这项工作的结果也可能影响我们对癌症等疾病的理解。其次，这项研究将揭示特定的泛素化事件如何影响染色质结构，染色质结构是许多不同生物过程的基础。这个项目的一个新主题是泛素化可能改变核小体之间的相互作用，从而调节基因组特定部分的可及性。由于泛素化在细胞内稳态中起着重要的作用，并且在广泛的人类疾病中处于失调状态，这些研究的结果也将对染色质生物学的直接领域产生广泛的影响。

 DESCRIPTION (provided by applicant): The long-term goal the research program generates paradigms for how the protein ubiquitylation regulates chromatin dynamics during DNA replication. Recent evidence has shown that components of the protein ubiquitylation system are involved- directly and mechanistically - in numerous important biological processes- such as gene activation (including co-activator recruitment, co-transcriptional mRNA processing, and transcriptional termination), DNA damage repair and DNA replication. Yet the underlying molecular mechanisms at work remain obscure. To understand the fundamental ways in which ubiquitin (Ub), and Ub-ligases can influence chromatin mediated biological processes, this project focuses on exposing how chromatin structures are modulated by histone ubiquitylation events, how DNA polymerase is modulated by Ub-mediated nucleosome dynamics. These studies take advantage of the chemically synthesized histone carrying site-specific Ub, and employ cutting-edge biochemical and genomic approaches to define both the mechanism and significance of control of transcription and replication by protein ubiquitylation. Results of thes studies will have broad impact in two main areas. First, they will illuminate a poorly understood aspect of DNA replication. It has only recently been appreciated that ubiquitylation is directly involved in replication, and although this is a rapidly evolving field, general themes and processes have yet to be defined. These studies will define these general themes, and in so doing reveal novel ways in which DNA replication is regulated. Results of this work are also likely to impact our understanding of diseases such as cancer. Second, this research will reveal how specific ubiquitylation events may affect chromatin architecture, which underlie many distinct biological processes. An emerging theme in this project is that ubiquitylation may alter inter- nucleosome interactions and thus regulate accessibility of specific part of the genome. As the ubiquitylation plays a prominent role in cellular homeostasis and is dysregulated in a wide spectrum of human diseases, results of these studies will also have broad impact beyond the immediate field of chromatin biology.