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 重塑是指真核细胞染色体的动态紧凑和解聚 通过核小体的共价修饰和物理运动。了解以下内容 推动重塑的过程对于更深入地了解人类是必不可少的 由于正常基因调控中断而导致的疾病，如癌症和遗传性疾病 发育障碍。关于ATP-1的作用机制，人们知之甚少 依赖的重塑因子改变核小体结构，但不了解有多明显 重塑器域在功能上相互作用以促进重塑，重塑器域的关键是什么 相互之间在空间中的位置，也不是重构体如何拥抱核小体 底物。 这项提议的长期目标是建立一种生化和生物物理 描述和理解染色质重塑过程所必需的框架。这 提案集中在CHD1染色质重塑因子上，具体目的是(1)解剖 CHD1的重塑周期通过表征部分功能失调的变异，(2)决定 使用X射线结晶学的CHD1重建器的结构，以及(3)确定 使用小角X射线散射(SAXS)和DNA足迹的核小体复合体。通过 将CHD1的功能研究与X射线结晶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发展治疗的关键 操控全基因组的基因表达来治疗人类疾病。人体内几乎所有的细胞都拥有相同的一组基因，但只有一部分 这些基因在任何特定的组织中都是“开启”的。基因的“开”和“关”状态 以一种复杂和定义模糊的方式进行监管，直接与 染色体的物理包装，称为染色质结构。了解 染色体拆解和重新打包的过程，所谓的 染色质重塑因子对于理解和对抗染色质重塑是必要的 许多疾病，如癌症，在基因表达上存在不平衡。

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.