Mechanisms and Consequences of Specific Chromatin Arrangements in vivo

项目摘要/摘要 染色质结构是真核基因表达的主要决定因素，染色质的调节是一种 所有动态细胞反应的基本步骤。染色质调节不当导致发育 缺陷和人类癌症。该项目的总体目标是了解 染色质结构在静态基因组中编码，并决定这些变化是如何在 特定于条件的方式。为了开始实现这一目标，我们正在模拟特定条件的建立 核小体定位于转录因子靶向染色质重塑蛋白。而特定于序列 众所周知，转录因子招募并与染色质重塑机制相互作用，这些 相互作用调节核小体定位结果在很大程度上是不确定的。最近的研究表明 Ume6-招募的ISW2复合体导致了高精度的基序近端核小体定位。这个 这些特定的染色质重塑事件的机制将使用以下组合进行剖析 生物化学和基因组学回答以下三个基本问题：1)Ume6是如何 与ISW2的相互作用导致Ume6靶点的基序近端核小体选择。2)期末考试怎么样 通过Ume6-ISW2相互作用和ISW2自身调节实现核小体定位。3)Motif如何- Ume6靶点的近端核小体位置影响转录抑制。回答这些问题是 对于阐明特定的染色质片段如何以可预测的方式重新排列至关重要，并将提供 一个概念性框架，通过它，特定条件的序列靶向染色质重塑事件可以 被理解。

Project Summary/Abstract Chromatin structure is a major determinant of eukaryotic gene expression, and the regulation of chromatin is a fundamental step in all dynamic cellular responses. Improper regulation of chromatin leads to developmental defects and human cancers. The overall goal of this project is to understand how dynamic changes in chromatin structure are encoded in a static genome, and determine how these changes are orchestrated in a condition-specific manner. To begin to achieve this goal, we are modeling condition-specific establishment of nucleosome positions by a transcription factor-targeted chromatin remodeling protein. While sequence-specific transcription factors are widely known to recruit and interact with chromatin remodeling machinery, how these interactions regulate nucleosome positioning outcomes is largely undetermined. Recent studies have shown that Ume6-recruited ISW2 complex leads to highly precise motif-proximal nucleosome positioning. The mechanism of these specific chromatin remodeling events will be dissected using a combination of biochemistry and genomics to answer the following three fundamental questions: 1) How does Ume6 interaction with ISW2 lead to motif-proximal nucleosome selection at Ume6 targets. 2) How is the final nucleosome position achieved through Ume6-ISW2 interactions and ISW2 autoregulation. 3) How do motif- proximal nucleosome positions at Ume6 targets affect transcriptional repression. Answering these questions is critical to elucidating how specific chromatin segments are rearranged in a predictable manner, and will provide a conceptual framework through which condition-specific sequence-targeted chromatin remodeling events can be understood.