Structural and Functional Analysis of the CHD1 Chromatin Remodeler

染色体的物理组织与基因调控密切相关。染色质 重塑是指真核生物染色体的动态压缩和解压缩 通过核小体的共价修饰和物理运动。知识 驱动重塑的过程对于更深入地了解人类的行为至关重要。 由正常基因调控中断引起的疾病，如癌症和遗传性疾病。 发育障碍关于ATP的作用机制，我们知之甚少。 依赖性重塑因子改变核小体结构，但不了解它们如何不同。 重塑结构域在功能上相互作用，以促进重塑，关键重塑结构域是如何 在空间上相互定位，也不知道重塑者如何拥抱核小体， 衬底 这项建议的长期目标是建立一个生物化学和生物物理 这是描述和理解染色质重塑过程所必需的框架。这 该提案的重点是CHD1染色质重塑因子，具体目标是（1）解剖 通过表征部分功能障碍的变体，（2）确定CHD1重塑周期， 使用X射线晶体学确定CHD1重塑器的结构，以及（3）确定 a使用小角X射线散射（SAXS）和DNA足迹法的CHD1：核小体复合物。通过 将CHD1的功能研究与通过X射线晶体学获得的结构信息相结合， SAXS和DNA足迹，我们希望阐明重塑反应的关键步骤。在 未来，对染色质重塑的深入了解将是开发治疗方法的关键 操纵全基因组基因表达来治疗人类疾病。几乎所有的人体细胞都具有相同的基因组，但只有一个子集， 这些基因在任何特定的组织中被“打开”。基因的“开”和“关”状态 以一种复杂和不明确的方式受到监管， 染色体的物理包装，称为染色质结构。了解 染色体可以通过所谓的“包装”和“重新包装”的过程 染色质重塑因子是理解和对抗 许多疾病，如癌症，基因表达不平衡。

The physical organization of chromosomes is intimately tied to gene regulation. Chromatin remodeling refers to the dynamic compaction and decondensation of eukaryotic chromosomes through the covalent modification and physical movement of nucleosomes. Knowledge of the processes that drive remodeling are essential for gaining a more insightful understanding of human diseases that result from disruptions of normal gene regulation, such as cancer and inherited developmental disorders. Relatively little is known regarding the mechanism of by which ATP- dependent remodeling factors alter nucleosome structure, with no understanding of how distinct remodeler domains functionally interact to promote remodeling, how key remodeler domains are positioned in space with respect to one another, nor how remodelers embrace the nucleosome substrate. The long-term objective of this proposal is to establish a biochemical and biophysical framework necessary for describing and understanding the process of chromatin remodeling. This proposal focuses on the CHD1 chromatin remodeling factor, with specific aims to (1) dissect the CHD1 remodeling cycle by characterizing partially dysfunctional variants, (2) determine the architecture of the CHD1 remodeler using X-ray crystallography, and (3) determine the organization of a CHD1:nucleosome complex using small angle X-ray scattering (SAXS) and DNA footprinting. By coupling functional studies of CHD1 with structural information gained through X-ray crystallography, SAXS, and DNA footprinting, we expect to elucidate key steps of the remodeling reaction. In the future, a deeper understanding of chromatin remodeling will be essential for developing therapeutics that manipulate genome-wide gene expression for treatment of human disease. Nearly all cells in the human body possess the same set of genes, yet only a subset of these genes are turned "on" in any particular tissue. The "on" and "off" states of genes are regulated in a complex and ill-defined manner that directly correlates with the physical packaging of chromosomes, called the chromatin structure. Understanding the process by which chromosomes can be unpackaged and repackaged by so-called chromatin remodeling factors is necessary for understanding and therefore combatting many diseases such as cancer where there are imbalances in gene expression.