Mechanistic Analysis of Chromatin Remodeling

描述（由申请人提供）将DMA包装到染色质中，使得其在转录、复制、重组和修复等核心核过程中基本上无法进入。依赖atp的染色质重塑复合物在染色质动力学中起关键作用。然而，这些复合物的作用机制在很大程度上是未知的。本提案的总体目标是使用机械酶学工具来了解主要的atp依赖性染色质重塑复合体，人类SWI/SNF，如何催化来自染色质的DMA暴露。SWI/SNF复合物在一些基因的转录调控以及基于细胞周期的染色体结构调控中起着至关重要的作用。与这些作用一致的是，这些复合物成分的突变与严重的发育缺陷和多种癌症有关。对SWI/SNF机制的详细了解将有助于深入了解其活动是如何调节的以及它是如何发生故障的。该项目的具体目标是：(1)确定染色质重塑中导致DNA稳定暴露的单个步骤。(2)确定SWI/SNF如何利用ATP结合和水解的能量来重塑染色质。(3)分析单个SWI/SNF亚基的机制贡献。

DESCRIPTION (provided by applicant) The packaging of DMA into chromatin makes it largely inaccessible for the central nuclear processes of transcription, replication, recombination and repair. ATP-dependent chromatin remodeling complexes play a key role in making chromatin dynamic. However, the mechanisms by which these complexes function are largely unknown. The overall goal of this proposal is to use the tools of mechanistic enzymology to understand how a major ATP-dependent chromatin remodeling complex, human SWI/SNF, catalyzes exposure of DMA from chromatin. SWI/SNF complexes play crucial roles in the transcriptional regulation of several genes as well in the cell cycle based regulation of chromosome structure. Consistent with these roles, mutations in the components of these complexes are associated with severe developmental defects and a variety of cancers. A detailed understanding of SWI/SNF mechanism will provide insights into how its activity is regulated and how it malfunctions. The specific aims of this project are: (1) To identify the individual steps in chromatin remodeling that lead to stable exposure of DNA. (2) To determine how SWI/SNF uses the energy of ATP binding and hydrolysis for remodeling chromatin. (3) To dissect the mechanistic contributions of individual SWI/SNF subunits.