Structural mechanisms of chromatin assembly

染色质组装的结构机制

• 批准号: 10569022
• 负责人: MAIR E CHURCHILL
• 金额: $ 39.13万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-04 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10569022
• 关键词: Address; Antigen Targeting; Architecture; Area; Binding; Binding Sites; Biochemical; Biology; Biophysics; Cell Nucleus; Cell Proliferation; Cells; Chromatin; Chromatin Modeling; Chromatin Structure; Complement; Complex; DNA; DNA Binding; DNA Repair; DNA biosynthesis; DNA replication fork; Data; Deposition; Development; Disease; Double Strand Break Repair; Epigenetic Process; Eukaryotic Cell; Genetic Recombination; Genetic Transcription; Genome; Goals; Growth; Histone H3; Histone H4; Histones; Investigation; Knowledge; Learning; Length; Malignant Neoplasms; Maps; Mediating; Medical Research; Modeling; Molecular; Molecular Biology; Molecular Chaperones; Nucleosomes; Outcome Study; Pathway interactions; Process; Proliferating Cell Nuclear Antigen; Proteins; Public Health; Recruitment Activity; Research; Resected; Role; Single-Stranded DNA; Site; Structure; Testing; Work; biophysical properties; chromatin assembly factor I; combinatorial; dimer; epigenetic regulation; experimental study; homologous recombination; human disease; in vivo; insight; interest; mutant; novel; prevent; recruit; tool; transcription factor

Project Summary The packaging of the genome into chromatin that is essential for normal growth, development, and differentiation has been a focus of the lab for more than 20 years. Nucleosomes are the basic repeating unit of the chromatin structure that tightly regulates all of the processes that use DNA as a substrate, including transcription, DNA replication, DNA repair, and recombination. The intricate steps of nucleosome assembly are guided by histone chaperones that are critical to prevent the aberrant nonspecific interactions of histone proteins. The key proteins responsible for replication-dependent assembly of nascent histone H3 and H4 are the H3/H4 histone chaperones, Anti-silencing function 1 (Asf1) and Chromatin Assembly Factor (CAF-1). The proliferating-cell nuclear antigen (PCNA) targets chromatin assembly to sites of newly replicated DNA. Our biophysical and structural studies have revealed unexpected, novel and fundamental insights into the early stages of replication-dependent chromatin assembly, namely the hand-off mechanism involving transfer of dimers of H3/H4 from Asf1 to CAF-1, and the architectural features of CAF-1 interactions with H3/H4. While the general functions of these histone chaperones in nucleosome assembly are known, the fundamental molecular and structural mechanisms for these functions remain obscure. As such, this proposal explores questions about important and understudied aspects of H3/H4 histone chaperone activity from the recruitment and mechanism of action at sites of DNA replication which impact the fidelity of epigenetic inheritance as well as a newly-discovered role in the assembly of single-stranded nucleosomes. To answer these questions, biophysical and structural approaches, which have been specifically developed to study histone chaperones will be used together with complementary biochemical and molecular biology approaches in cells. The outcomes of these studies will be a better understanding of the structural mechanisms involved in the process of deposition of H3/H4 onto DNA during nucleosome assembly, and these new insights may inform how chromatin landscapes are established and how the histone chaperones might be manipulated for the purpose of epigenetic regulation in medical research applications and human disease.

项目摘要 将基因组包装成染色质，这对于正常生长，发育和 差异化已成为实验室的重点超过20年。核小体是 密切调节使用DNA作为底物的所有过程的染色质结构，包括 转录，DNA复制，DNA修复和重组。核小体组装的复杂步骤是 在组蛋白伴侣的指导下，这对于预防组蛋白异常非特异性相互作用至关重要 蛋白质。负责复制依赖性组装的新生组蛋白H3和H4的关键蛋白是 H3/H4组蛋白伴侣，抗沉淀功能1（ASF1）和染色质组装因子（CAF-1）。这 增殖细胞核抗原（PCNA）将染色质组装靶向新复制DNA的位点。我们的 生物物理和结构研究揭示了对早期的意外，新颖和基本的见解 复制依赖性染色质组装的阶段，即涉及转移的交接机制 H3/H4的二聚体从ASF1到CAF-1，以及与H3/H4的CAF-1相互作用的架构特征。尽管 这些组蛋白伴侣在核小体组装中的一般功能是已知的，是基本的 这些功能的分子和结构机制仍然晦涩。因此，该建议探讨 有关招聘的H3/H4组蛋白伴侣活动的重要和研究的问题 以及在DNA复制位点的作用机理，这也影响了表观遗传遗传的保真度 作为单链核小体组装中新发现的作用。要回答这些问题， 生物物理和结构方法，已专门为研究组蛋白伴侣而开发 将与细胞中的互补生化和分子生物学方法一起使用。这 这些研究的结果将更好地理解该过程中涉及的结构机制 在核小体组装过程中H3/H4沉积在DNA上的沉积，这些新见解可能会告知如何 建立染色质景观以及如何为目的操纵组蛋白伴侣 医学研究应用和人类疾病中的表观遗传调节。