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.

重组在维持基因组稳定性方面是必不可少的，即使重组中的微小缺陷也是如此。 双链断裂（DSB）修复途径导致癌症或其它严重疾病。初加工 将DNA双链断裂成单链的过程称为DNA末端切除，是同源重组的关键第一步。 损伤反应和修复蛋白的加载所需的重组。切除手术严格控制在 细胞周期，并决定同源重组与非同源末端连接的使用， 修复.在酵母和人类细胞中，Mre 11-Rad 50-Nbs 1/Xrs 2复合物启动切除，而Exo 1或 Sgs 1-Dna 2介导广泛切除。迄今为止，切除术的系统研究仅在 因此，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 许多新的检测方法来检测分裂酵母中转录沉默染色质内的切除（目标#1）。的 裂殖酵母系统为这项研究提供了一个很好的模式生物，因为染色质特征很好， 与人类细胞中的那些保持一致。在目标#2中，我们专注于控制最具致突变性的途径之一， DSB修复称为断裂诱导复制（BIR）。BIR通常用于修复单端DSB。这里 我们的目标是了解在双端DSB的修复过程中该通路是如何被抑制的。我们专注于 Rad 52退火ssDNA和Mre 11-Rad 50-Xrs 2同步切除DSB两端的作用 复杂.在目标#3中，我们专注于DNA 2核酸酶/解旋酶的切除独立功能， 同源重组