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.

项目摘要/摘要 DNA可能会出现双链断裂（DSB），从暴露于辐射和我们的污染物中流行的污染物 环境。 DSB的不准确维修可能导致基因组重排，这可能导致智力 残疾，神经退行性，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），取决于不同的 因素和机械上的不同。重要的是，DNA断裂也可以经历微观学 - 介导的末端连接（MMEJ），其中最终切除触发器暴露于ssDNA尾巴中的同源性有限 DNA链退火以启动末端连接维修。 MMEJ导致DNA序列的缺失 在微观学区域之间。因此，MMEJ是高度诱变的，并且是癌细胞的标志。 MMEJ具有专用DNA聚合酶Polq的发现，并且经常使用 即使NHEJ和HR完整支持MMEJ是进化保守的DSB修复的前提 路径。 缺乏NHEJ和HR缺乏的肿瘤细胞在化学治疗后严重依赖MMEJ来生存能力 DNA破坏代理。因此，MMEJ失活会使肿瘤细胞对此类治疗敏感。一个主要目标 当前的MMEJ研究是确定调节或直接催化MMEJ的新因素，以定义遗传 以及它们发挥作用的生化基础，并测试其作为潜在可毒靶标的价值。我们 已将RTEL1识别为有效MMEJ所需的新因素。 RTEL1编码必需的DEAH 解放各种DNA结构的解旋酶，包括钥匙重组中间体，位移 循环（D环）。我们假设RTEL1通过解离D环结构来促进MMEJ，否则 与mmej竞争。我们的模型解释了有关人力资源的抑制作用的几个神秘观察 MMEJ中的因素，并提供了一个理解与RTEL1相关的病理学的机械框架 疾病。我们将使用分子遗传学和体外生物化学的结合来测试这种创新的思想。 该项目将更好地定义MMEJ及其法规的机制，并可能揭示可能是 针对治疗环境诱发的疾病，例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强烈影响。