Role of RTEL1 in Microhomology-Mediated End Joining

RTEL1 在微同源介导的末端连接中的作用

• 批准号: 10304187
• 负责人: JAMES MATTHEW DALEY
• 金额: $ 23.25万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-11-18 至 2023-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10304187
• 关键词: 20q13; BRCA deficient; Biochemical; Biochemistry; Biological Assay; Breast; Cancer cell line; Cells; Chromosomal Rearrangement; DNA; DNA Damage; DNA Double Strand Break; DNA Repair; DNA Sequence; DNA Structure; DNA-Directed DNA Polymerase; Disease; Double Strand Break Repair; Environment; Environmental Health; Enzymes; Equilibrium; Event; Excision; Exposure to; Frequencies; Genetic; Genetic Epistasis; Genetic Recombination; Genome; Glioma; Goals; Immunodeficiency and Cancer; In Vitro; Intellectual functioning disability; Knowledge; Lead; Malignant Neoplasms; Malignant neoplasm of ovary; Mediating; Modeling; Molecular Genetics; Mutagenesis; Mutagens; Mutation; Nerve Degeneration; Nonhomologous DNA End Joining; Ovarian; Pathologic Mutagenesis; Pathology; Pathway interactions; Pharmaceutical Preparations; Pharmacology; Proteins; Pulmonary Fibrosis; Radiation; Reaction; Regulation; Reporter; Research; Resected; Role; Site; Structure; Tail; Testing; Therapeutic; Work; anti-cancer; cancer cell; drug sensitivity; druggable target; genotoxicity; helicase; homologous recombination; inhibitor; innovation; malignant breast neoplasm; neoplastic cell; nervous system disorder; novel; pollutant; predictive modeling; reconstitution; repaired

PROJECT SUMMARY/ABSTRACT Double-strand breaks (DSBs) can arise in DNA from exposure to radiation and pollutants prevalent in our environment. Inaccurate repair of DSBs can lead to genome rearrangements, which can cause intellectual disability, neurodegeneration, immunodeficiency, and cancer. DSBs are removed by two major pathways: nonhomologous end joining (NHEJ) and homologous recombination (HR), which are dependent on different factors and are mechanistically very distinct. Importantly, DNA breaks can also undergo microhomology- mediated end joining (MMEJ), in which limited homology in the ssDNA tails exposed by end resection triggers DNA strand annealing to initiate end joining repair. MMEJ leads to deletion of the DNA sequence situated between the regions of microhomology. As such, MMEJ is highly mutagenic, and is a hallmark of cancer cells. The discoveries that MMEJ possesses a dedicated DNA polymerase, POLq, and that it is employed frequently even when NHEJ and HR are intact support the premise that MMEJ is an evolutionarily conserved DSB repair pathway. Tumor cells deficient in NHEJ and HR rely heavily on MMEJ for viability upon treatment with chemotherapeutic DNA damaging agents. Inactivation of MMEJ would thus sensitize tumor cells to such treatments. A major goal of current MMEJ research is to identify novel factors that regulate or directly catalyze MMEJ, to define the genetic and biochemical underpinnings by which they function, and to test their value as potential druggable targets. We have identified RTEL1 as a novel factor that is required for efficient MMEJ. RTEL1 encodes an essential DEAH helicase that disassembles various DNA structures including a key recombination intermediate, the displacement loop (D-loop). We hypothesize that RTEL1 promotes MMEJ by dissociating D-loop structures that otherwise compete with MMEJ. Our model explains several enigmatic observations regarding the inhibitory roles of HR factors in MMEJ and provides a mechanistic framework for understanding the pathology of RTEL1-associated diseases. We will test this innovative idea using a combination of molecular genetics and in vitro biochemistry. This project will better define the mechanism of MMEJ and its regulation, and may reveal factors that can be targeted to treat environmentally induced diseases such as cancer and neurological disorders. As such, our work will exert a strong impact on environmental health research.

项目总结/摘要 双链断裂（DSB）可能会出现在DNA暴露于辐射和污染物普遍在我们的 环境DSB的不准确修复可能导致基因组重排，这可能导致智力低下。 残疾、神经退化、免疫缺陷和癌症。DSB通过两种主要途径去除： 非同源末端连接（NHEJ）和同源重组（HR），它们依赖于不同的 这些因素在机械上非常不同。重要的是，DNA断裂也可以经历微同源性- 介导的末端连接（MMEJ），其中通过末端切除暴露的ssDNA尾部中的有限同源性触发 DNA链退火以启动末端连接修复。MMEJ导致位于 在微同源区域之间。因此，MMEJ是高度致突变的，并且是癌细胞的标志。 发现MMEJ具有专用的DNA聚合酶POLq，并且经常使用 即使当NHEJ和HR是完整的支持的前提下，MMEJ是一个进化保守的DSB修复 通路 NHEJ和HR缺陷的肿瘤细胞在用化疗药物治疗后严重依赖于MMEJ的活力 DNA破坏剂。因此，MMEJ的失活将使肿瘤细胞对这种治疗敏感。一个主要目标 目前MMEJ研究的主要目的是鉴定调节或直接催化MMEJ的新因子， 以及它们发挥作用的生化基础，并测试它们作为潜在药物靶点的价值。我们 已经确定RTEL 1作为一个新的因素，是需要有效的MMEJ。RTEL 1编码一种重要的DEAH 解旋酶，分解各种DNA结构，包括关键的重组中间体，置换 循环（D循环）。我们假设RTEL 1通过解离D环结构促进MMEJ，否则 与MMEJ竞争。我们的模型解释了一些关于HR抑制作用的神秘观察结果 在MMEJ的因素，并提供了一个机制框架，了解RTEL 1相关的病理 疾病我们将使用分子遗传学和体外生物化学的组合来测试这个创新的想法。 该项目将更好地定义MMEJ及其调节的机制，并可能揭示可以 靶向治疗环境引起的疾病，如癌症和神经系统疾病。因此，我们的工作 将对环境健康研究产生重大影响。