RAD51 paralog function in cancer predisposition and genome integrity

项目概要/摘要： DNA损伤的准确修复对于遗传稳定性和防止与衰老相关的退化至关重要 和癌症我们正在努力确定调控DNA双链断裂精确修复的关键因素 通过无错同源重组（HR）途径，在DSB中表达。争端解决机构可以由许多来源产生 包括内源性复制叉损伤、外源性环境毒物或氧化应激 由内源性来源和在对毒物损伤的促炎反应期间诱导。我们发现 RAD 51旁系同源物对于促进HR并且因此对于抑制易错修复机制是至关重要的。超过 300项研究将人类RAD 51旁系同源基因突变与癌症以及乳腺癌或卵巢癌女性联系起来 现在正在筛查是否有RAD 51突变。然而，在很大程度上仍然不知道RAD 51是哪种 突变是致病性的，以及这些突变如何使个体对环境诱导的DNA敏感， 由于我们缺乏对野生型或突变蛋白质的功能分析，我们不知道如何 这些蛋白质被招募，它们的功能成分，或突变引起的破坏， RAD 51旁系同源物中的多态性。这种知识差距是由于内源性 RAD 51蛋白质、重组蛋白质的不溶性以及敲除中的胚胎致死性 小鼠因此，我们正在使用遗传，生物化学和细胞生物学方法来表征RAD 51 在暴露于DSB诱导剂后，我们将使用电离辐射（IR）和博来霉素作为 环境相关的DSB诱导剂的模型剂。使用互补方法， 结合高通量遗传筛选，我们现在独特地准备解决如何RAD 51 突变使个体易患人类癌症，因此，为了确定确定 在暴露于环境致癌物时处于癌症发展风险中的人。我们的最终目标是 为肿瘤携带RAD 51的个体患者制定精准医疗策略 突变谱。

Project Summary/Abstract: Accurate repair of DNA damage is critical for genetic stability, and for preventing aging-related degeneration and cancer. We are working to identify key factors that regulate accurate repair of DNA double-strand breaks (DSBs) through the error-free homologous recombination (HR) pathway. DSBs can arise from many sources including endogenous replication fork damage, exogenous environmental toxicants, or oxidative stresses induced by endogenous sources and during pro-inflammatory responses to toxicant injury. We found that the RAD51 paralogs are critical for promoting HR and hence for suppressing error-prone repair mechanisms. Over 300 studies link mutations in human RAD51 paralogs with cancer, and women with breast or ovarian cancer are now screened for RAD51 paralog mutations. However, it remains largely unknown which RAD51 paralog mutations are pathogenic and how these mutations sensitize individuals to environmentally induced-DNA damage due to our lack of functional analysis of either the wild-type or mutated proteins. We do not know how these proteins are recruited, their functional components, or the disruptions caused by mutations or polymorphisms in the RAD51 paralogs. This knowledge gap results from low abundance of endogenous RAD51 paralog proteins, insolubility of the recombinant proteins, as well as embryonic lethality in knock-out mice. We are therefore using genetic, biochemical, and cell biological approaches to characterize RAD51 paralog function upon exposure to DSB inducing agents. We will use ionizing radiation (IR) and bleomycin as model agents for environmentally relevant DSB-inducing agents. Using complementary approaches in combination with high-throughput genetic screening, we are now uniquely poised to address how RAD51 paralog mutations predispose individuals to human cancer and thus, to identify opportunities for determining who is at risk for cancer development upon exposure to environmental carcinogens. Our ultimate goal is to enable development of precision medicine strategies for individual patients whose tumors harbor a RAD51 paralog mutation profile.