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: 10447082
• 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/10447082
• 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; 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.

项目摘要 核苷酸切除修复（NER）途径是负责去除 大体积DNA损伤，如紫外线照射形成的损伤。它是高度保守的， 失调与人类疾病如着色性干皮病有关。在细胞中，NER 它不是发生在裸露的DNA模板上，而是发生在称为染色质的DNA-蛋白质复合物上。的 染色质的完整性和结构动力学是正常功能的基础， 所有真核生物的生存。染色质结构的变化直接影响基因组 可及性以及因此通过NER的核过程如DNA损伤修复。然而我们的 关于NER如何在其天然环境中发生的知识，染色质是有限的。新兴 有证据表明两个关键的染色质调节因子在调节染色质中起重要作用 动力学，以促进在NER损害修复。这两个调节器是INO 80 ATP- 依赖性染色质重塑蛋白和异染色质蛋白1。更重要的是 这些蛋白质在NER中的功能似乎至少部分是由于它们与蛋白质相互作用的能力。 NER修复因子（例如，UV-DDB复合物）和/或染色质结构组分（例如， 组蛋白变体H2A.Z）。 阐明染色质结构动力学调控的分子机制， 它与DNA损伤修复偶联，我们将使用单粒子冷冻电子组合 显微镜（EM），传统的生物化学和生物物理技术，以解决以下问题 问题：（1）组蛋白变异体介导的染色质折叠的结构基础是什么 H2A.Z？(2)连接体组蛋白H1对染色质致密化的结构机制是什么？（三） 先前存在的染色质环境如何影响NER通路中的病变检测？(4)做 核小体上的光损伤干扰INO 80介导的ATP依赖性染色质 INO 80在光损伤中的募集机制是什么？(5)是什么 HP 1靶向染色质光损伤的分子和结构机制？总体而言，这 这项工作将大大提高我们对染色质在基因组监视中所起作用的理解。 系统它还将提供关键的见解，如何调控染色质结构动力学 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。