Structural and Functional Characterization of the Chd1 Chromatin Remodeler

Chd1 染色质重塑剂的结构和功能表征

• 批准号: 10798558
• 负责人: GREGORY DEAN BOWMAN
• 金额: $ 19.33万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10798558
• 关键词: ATP phosphohydrolase; Address; Affect; Binding; Binding Sites; Biological Models; CHD1 gene; Chromatin; Coupled; DNA; DNA Binding Domain; DNA Sequence; Defect; Elements; Enzymes; Experimental Designs; Genes; Genome; Growth and Development function; Health; Human; Kinetics; Link; Malignant Neoplasms; Molecular Conformation; Motor; Mutation; Nucleosomes; Nucleotides; Physical shape; Positioning Attribute; Process; Regulation; Role; Side; Slide; Structure; Testing; absorption; cancer type; cell growth; chromatin remodeling; developmental disease; human disease; insight; preference; translocase

ABSTRACT Chromatin remodelers are ATP-dependent DNA translocases that catalyze disassembly, reassembly, and repositioning of nucleosomes throughout eukaryotic genomes. As evidenced from multiple types of cancer and developmental disorders associated with remodeler mutations, chromatin remodeling is essential for normal growth and development. This proposal aims to address core mechanistic questions of remodeler action and regulation, using the Chd1 chromatin remodeler as a model system. Recent studies revealed that chromatin remodelers shift nucleosomes using a twist defect mechanism. In this process, remodelers couple distinct nucleotide-dependent conformations of the ATPase motor to create and then eliminate DNA distortions (twist defects) that stimulate the nucleosome to transiently absorb and then release an extra bp at the remodeler binding site. Currently, it is unknown how remodelers create twist defects. Aim 1 of this proposal seeks to identify key residues and elements of Chd1 necessary for distorting DNA into twist defects, which should allow for a mechanistic understanding of this central process. Another question addressed by this proposal is how remodeler ATPases are regulated. For Chd1, nucleosome sliding activity is coupled to DNA outside the nucleosome, with a requirement for flanking DNA on the “entry” side and preference for little or no DNA on the “exit” side. For Chd1, flanking DNA controls sliding activity through a DNA-binding domain that is coupled to autoinhibitory elements. A central question addressed by Aim 2 of this proposal is how stability and interactions of autoinhibitory elements are controlled by distinct domain arrangements on the nucleosome. Experiments are designed to reveal kinetic transitions of remodeler rearrangements on the nucleosome. Finally, a major unanswered question is how two remodelers bound to the same nucleosome affect activity of each other. Chd1 has been shown to bind to nucleosomes in a 2:1 ratio, with the DNA-binding domain interacting in trans with the chromo-ATPase, yet the significance of these interactions is unknown. Aim 3 tests the hypothesis that two opposing remodelers bound to the same nucleosome antagonize each other. Together, these studies will provide new mechanistic insights into how remodelers alter nucleosome structure, autoregulate action of their central ATPase motor, and coordinate and potentially control other remodelers on the nucleosome.

抽象的 染色质远方是ATP依赖性的DNA易位酶，可催化拆卸，重新组装和 整个真核基因组的核小体重新定位。从多种类型的癌症和 与重塑突变相关的发育障碍，染色质重塑对于正常 增长与发展。该提案旨在解决改建措施的核心机理问题和 调节，使用CHD1染色质重塑作为模型系统。最近的研究表明染色质 远程使用使用扭曲缺陷机制移动核小体。在此过程中，远程夫妇截然不同 ATPase电动机的核苷酸依赖性考虑因素，然后消除DNA失真（扭曲 刺激核小体以瞬时吸收然后在重塑器处释放额外BP的缺陷） 绑定位点。目前，远程如何产生扭曲缺陷是未知的。本提案的目标1试图 确定将DNA扭曲成扭曲缺陷所必需的CHD1的密钥保留和元素，这应允许 为了了解这一中央过程。该提议解决的另一个问题是如何 调节重塑ATPase。对于CHD1，核小体滑动活性与DNA耦合 核小体，需要在“入口”侧侧翼DNA，并且偏爱很少或没有DNA “退出”一面。对于CHD1，DNA的侧翼控制通过DNA结合域的滑动活性，该结合结构域耦合到 自身抑制元素。该提案的AIM 2提出的一个主要问题是稳定性和互动方式 自身抑制元件的元素受核小体上不同的域排列控制。实验是 旨在揭示核小体上重塑重新排列的动力学转变。最后，一个少校 未解决的问题是两个远程如何与相同的核小体互相影响彼此的活性。 CHD1 已显示以2：1的比例与核小体结合，而DNA结合结构域则与Trans相互作用 Chromo-ATPase，但这些相互作用的重要性尚不清楚。 AIM 3检验了两个假设 与同一核小体结合的相对远方相互拮抗。这些研究将在一起 提供有关如何改变核病结构的新机械洞察力，自动调节其作用 中央ATPase电动机，并在核小体上协调并可能控制其他远程。