Dynamics and Regulation of Chromatin in DNA Metabolism

DNA 代谢中染色质的动力学和调控

• 批准号: 10215566
• 负责人: Dongyan Tan
• 金额: $ 39.55万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-07 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10215566
• 关键词: Address; Architecture; Biochemistry; Cells; Chromatin; Chromatin Structure; Complex; Coupled; Cryoelectron Microscopy; DNA; DNA Damage; DNA Repair; DNA lesion; DNA metabolism; Defect; Detection; Disease; Environment; Enzymes; Eukaryota; Excision; Genome; Histone H1; Histones; Human; Knowledge; Lesion; Link; Malignant Neoplasms; Mediating; Molecular; Molecular Structure; Neurodevelopmental Disorder; Nuclear; Nucleosomes; Nucleotide Excision Repair; Pathway interactions; Play; Process; Proteins; Regulation; Role; Structure; System; Variant; Work; Xeroderma Pigmentosum; biophysical techniques; chromatin remodeling; heterochromatin-specific nonhistone chromosomal protein HP-1; improved; insight; novel therapeutic intervention; particle; photolesion; protein complex; protein function; recruit; repaired; response; ultraviolet irradiation

PROJECT SUMMARY The nucleotide excision repair (NER) pathway is the main pathway responsible for the removal of bulky DNA lesions such as those formed by UV irradiation. It is highly conserved and its deregulation is linked to human disorders such as xeroderma pigmentosum. In cells, NER does not occur on naked DNA templates, but on a DNA-protein complex called chromatin. The integrity and the structure-dynamics of chromatin are fundamental to the normal function and survival of all eukaryotes. Changes in chromatin architecture directly influence genome accessibility and thus nuclear processes such as DNA damage repair via NER. Yet our knowledge of how NER occurs in its native environment, chromatin is limited. Emerging evidence indicates the important role of two key chromatin regulator in modulating chromatin dynamics to facilitate damage repair in NER. These two regulators are the INO80 ATP- dependent chromatin remodeler and the heterochromatin protein 1. More importantly, the functions of these proteins in NER appear to be at least in part due to their ability to interact with either NER repair factors (e.g. UV-DDB complex) and/or chromatin structural components (e.g. histone variant H2A.Z). To elucidate the molecular mechanism of chromatin structure-dynamics regulation and how it is coupled to DNA damage repair, we will use a combination of single-particle cryo-electron microscopy (EM), traditional biochemistry and biophysical techniques to address the following questions: (1) what is the structural basis of chromatin folding mediated by histone variant H2A.Z? (2) What is the structural mechanism of chromatin compaction by linker histone H1? (3) How is preexisting chromatin environment impact lesion detection in the NER pathway? (4) Do photo lesions on nucleosome interfere with INO80-mediated ATP-dependent chromatin remodeling and what is the mechanism of INO80 recruitment to photo lesions? (5) What is the molecular and structural mechanism of HP1 targeting to photo lesion on chromatin? Overall, this work will greatly improve our understanding of the role chromatin play in genome surveillance system. It will also provide critical insights into how regulation of chromatin structure-dynamics via either histone proteins or chromatin associated factors influence key steps during repair.

项目总结 核苷酸切除修复(NER)途径是负责去除的主要途径 体积庞大的DNA损伤，如由紫外线辐射形成的损伤。它是高度保守的，它的 放松管制与人类疾病有关，如着色性干皮病。在单元格中，NER做到了 不是在裸露的DNA模板上，而是在一种名为染色质的DNA-蛋白质复合体上。这个 染色质的完整性和结构动力学是正常功能和 所有真核生物的生存。染色质结构的改变直接影响基因组 可获得性，从而通过NER修复DNA损伤等核过程。然而，我们的 由于对NER如何在其自然环境中发生的了解，染色质是有限的。新兴 证据表明两个关键的染色质调节因子在调节染色质中的重要作用 帮助修复NER中的伤害的动态效果。这两个调节器是INO80 ATP- 依赖染色质重构体和异染色质蛋白1。更重要的是， 这些蛋白在NER中的功能似乎至少部分归因于它们与 NER修复因子(例如UV-DDB复合体)和/或染色质结构成分(例如 组蛋白变异体H_2A.Z)。 阐明染色质结构-动力学调节的分子机制及其机制 它与DNA损伤修复相结合，我们将使用单粒子冷冻电子相结合 显微镜(EM)、传统生物化学和生物物理技术，以解决以下问题 问题：(1)组蛋白变体介导的染色质折叠的结构基础是什么？ H_2A.Z？(2)连接物组蛋白H1使染色质紧凑的结构机制是什么？(3) 先前存在的染色质环境如何影响NER通路中的损伤检测？(4) 核小体上的光损伤干扰INO80介导的ATP依赖的染色质 重塑以及INO80重新聚集到光斑的机制是什么？(5) HP1靶向染色质光损伤的分子和结构机制？总体而言，这 这项工作将极大地提高我们对染色质在基因组监测中所起作用的理解 系统。它还将为染色质结构-动力学的调节提供关键的见解 通过组蛋白或染色质相关因子影响修复过程中的关键步骤。