Regulation of Initial Steps of Chromosomal Breaks Repair

染色体断裂修复初始步骤的调控

• 批准号: 10554415
• 负责人: Grzegorz A Ira
• 金额: $ 32.96万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-01-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10554415
• 关键词: Acetylation; Address; Aging; Antibodies; Applications Grants; Biological Assay; Cell Cycle; Cells; Chromatin; Chromosomal Breaks; Chromosomal Stability; Complex; DNA; DNA Double Strand Break; DNA biosynthesis; Data; Defect; Disease; Double Strand Break Repair; Euchromatin; Excision; Fission Yeast; Future; Gene Conversion; Gene Targeting; Genetic Recombination; Genetic Transcription; Genome; Genome Stability; Genomics; Goals; Heterochromatin; Histone Deacetylase; Human; Invaded; Investigation; Laboratories; Malignant Neoplasms; Mediating; Medical; Minor; Mutation; Nonhomologous DNA End Joining; Pathway interactions; Play; Positioning Attribute; Process; Proteins; RAD52 gene; Regulation; Regulatory Pathway; Repetitive Sequence; Resected; Retrotransposon; Role; Saccharomycetales; Single-Stranded DNA; Site; System; Testing; Work; Yeast Model System; Yeasts; design; experimental study; genetic information; helicase; homologous recombination; human disease; interest; model organism; mutant; nuclease; permissiveness; prevent; repaired; response; restraint; telomere; yeast genome

Recombination is essential in maintaining genome stability, and even minor deficiency in recombinational double-strand break (DSB) repair pathways results in cancer or other severe diseases. The initial processing of DNA DSBs to single strands, a process termed DNA end resection, is the critical first step of homologous recombination needed for the loading of damage response and repair proteins. Resection is tightly controlled in the cell cycle and determines the usage of homologous recombination versus nonhomologous end joining for repair. In yeast and human cells, the Mre11-Rad50-Nbs1/Xrs2 complex initiates resection, whereas Exo1 or Sgs1-Dna2 mediates extensive resection. Systematic studies of resection have thus far only been done in euchromatin, whereas we propose to study it in three different types of silenced heterochromatin. We designed many new assays to examine resection within transcriptionally silent chromatin in fission yeast (Aim #1). The fission yeast system provides an excellent model organism for this study as chromatin features are well conserved with those in human cells. In Aim #2 we focus on control of one of the most mutagenic pathways of DSB repair called Break Induced Replication (BIR). BIR is normally used for the repair of a single-end DSB. Here the goal is to understand how this pathway is suppressed during the repair of two-ended DSBs. We focus on the role of ssDNA annealing by Rad52 and synchronous resection of two ends of a DSB by the Mre11-Rad50-Xrs2 complex. In Aim #3 we focus on the resection-independent function of Dna2 nuclease/helicase during homologous recombination.

重组对于维持基因组稳定性至关重要，甚至重组的轻微缺陷 双链断裂（DSB）修复途径会导致癌症或其他严重疾病。初步处理 DNA DSB 转化为单链，这一过程称为 DNA 末端切除，是同源序列的关键第一步 加载损伤反应和修复蛋白所需的重组。切除被严格控制在 细胞周期并确定同源重组与非同源末端连接的使用 维修。在酵母和人类细胞中，Mre11-Rad50-Nbs1/Xrs2 复合物启动切除，而 Exo1 或 Sgs1-Dna2 介导广泛切除。迄今为止，仅在以下领域进行了切除术的系统研究： 常染色质，而我们建议在三种不同类型的沉默异染色质中研究它。我们设计了 许多新的检测方法可检查裂殖酵母中转录沉默染色质内的切除情况（目标#1）。这 裂殖酵母系统为这项研究提供了一个极好的模型生物，因为染色质特征很好 与人类细胞中的保守。在目标 2 中，我们重点关注控制最具致突变性的途径之一 DSB 修复称为中断诱导复制 (BIR)。 BIR 通常用于修复单端 DSB。这里 我们的目标是了解在两端 DSB 修复过程中该通路是如何被抑制的。我们专注于 Rad52 进行 ssDNA 退火以及 Mre11-Rad50-Xrs2 同步切除 DSB 两端的作用 复杂的。在目标 #3 中，我们重点关注 Dna2 核酸酶/解旋酶在 同源重组。