Interrogating the roles of canonical versus variant histone H3 in genome function during aging

探讨经典组蛋白 H3 与变异组蛋白 H3 在衰老过程中基因组功能中的作用

• 批准号: 10677916
• 负责人: Jeanne-Marie McPherson
• 金额: $ 3.9万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10677916
• 关键词: ATAC-seq; Affect; Age; Aging; Amino Acid Sequence; Amino Acids; Binding; Cell Aging; Cell Cycle; Cells; Chromatin; Chromatin Structure; Clustered Regularly Interspaced Short Palindromic Repeats; DNA; DNA Packaging; DNA biosynthesis; Defect; Deposition; Development; Dose; Drosophila genus; Ensure; Eukaryota; Gene Dosage; Gene Expression; Gene Proteins; Genes; Genetic; Genetic Screening; Genetic Transcription; Genome; Genomics; Global Change; Heterochromatin; Histone H3; Histone H3.3; Histones; Homeostasis; Interphase Cell; Investigation; Knowledge; Location; Longevity; Mediating; Modeling; Mutation; Pathologic; Pathologic Processes; Pathway interactions; Pattern; Process; Proteins; Regulation; Role; S phase; Source; Testing; Variant; Work; aging brain; brain cell; defined contribution; experimental study; healthy aging; improved; insight; interest; postmitotic; protein function; screening; therapeutic development

PROJECT SUMMARY Histone proteins package and organize DNA into chromatin, which regulates every DNA-dependent process. Alterations to chromatin structure is a hallmark of aging and is characterized by global changes in gene expression, histone abundance, histone PTM landscape, and chromatin accessibility. I propose that tight control over histone abundance and histone type, which we term histone homeostasis, is essential for normal cellular aging. Cells contain two histone types: canonical histones that are expressed during S phase of the cell cycle, and variant histones that are expressed throughout the cell cycle and in non-dividing cells. Variant histones are of particular interest to aging because they are the only source of new histones in non-dividing cells and accumulate with age. Additionally, variant histone misregulation results in chromatin defects and reduced lifespan. Knowing how canonical and variant histones regulate genome function is integral to understanding normal and pathological chromatin-based aging processes. Canonical histone H3.2 and variant histone H3.3 are some of the most highly conserved proteins across eukaryotes. The high conservation of amino acid differences between canonical H3.2 and variant H3.3 suggests that they may perform unique functions in the genome, yet it is not understood if variant H3.3 function is mediated by its cell-cycle independent expression or unique protein sequence. In Drosophila, I have discovered that variant H3.3 is essential for development when canonical histone gene copy number is reduced, suggesting a previously unknown requirement for coordination between canonical H3.2 and variant H3.3 expression. However, the mechanisms underlying this coordination are unknown. The proposed project tests the hypotheses that variant H3.3 is required for normal chromatin-based aging processes and that cells possess a homeostatic mechanism to maintain the correct relative expression of canonical H3.2 and variant H3.3 throughout development. The aims of this project are to (1) determine the contributions of H3.3 expression versus protein sequence to chromatin-based aging processes and, (2) elucidate the mechanisms that achieve proper H3 abundance through the coordination of canonical and variant histone expression. This work will expand the fundamental understanding of how canonical and variant histones cooperate to regulate genome function during aging.

项目摘要 组蛋白蛋白包装并将DNA组织成染色质，从而调节每个DNA依赖性过程。 染色质结构的改变是衰老的标志，其特征是基因的全球变化 表达，组蛋白丰度，组蛋白PTM景观和染色质可及性。我提出了严格的控制 在组蛋白的丰度和组蛋白类型上，我们称其为组蛋白稳态，对于正常细胞是必不可少的 老化。细胞包含两种组蛋白类型：在细胞周期的S相表达的规范组蛋白， 以及在整个细胞周期和非分裂细胞中表达的变体组蛋白。变体组蛋白是 衰老特别感兴趣，因为它们是非分散细胞中新组蛋白的唯一来源， 随着年龄的增长而积聚。另外，变异组蛋白不调节导致染色质缺陷并减少 寿命。知道规范和变体组蛋白如何调节基因组功能是理解不可或缺的 正常和基于病理染色质的老化过程。规范组蛋白H3.2和变体组蛋白H3.3是 跨真核生物的一些最高度保守的蛋白质。氨基酸差异的高保护 在规范H3.2和变体H3.3之间，它们可能在基因组中执行独特的功能，但是 尚不清楚变体H3.3功能是通过其细胞周期独立表达或独特蛋白的介导的 顺序。在果蝇中，我发现变体H3.3对于规范时的开发至关重要 组蛋白基因拷贝数减少了，这表明先前未知的要求 规范H3.2和变体H3.3表达。但是，这种协调的基础机制是 未知。提出的项目测试了基于染色质的正常染色质需要变体H3.3的假设 衰老过程和细胞具有稳态机制，以维持正确的相对表达 在整个开发过程中，规范H3.2和变体H3.3。该项目的目的是（1）确定 H3.3表达与蛋白质序列对基于染色质的老化过程的贡献，（2）阐明 通过规范和变体组蛋白的协调实现适当H3丰度的机制 表达。这项工作将扩大对规范和变体组蛋白的基本理解 合作以调节衰老期间的基因组功能。