DSB REPAIR RECOMBINATION, AND GENOME STABILITY

DSB 修复重组和基因组稳定性

• 批准号: 6874378
• 负责人: Jac A Nickoloff
• 金额: $ 33.63万
• 依托单位: UNIVERSITY OF NEW MEXICO
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-18 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6874378
• 关键词: DNA damage; DNA repair; DNA replication; chromosome translocation; enzyme activity; gene expression; gene targeting; genome; ionizing radiation; phosphorylation; polymerase chain reaction; protein kinase C

DESCRIPTION (provided by applicant): The goal of the proposed research is to determine how proteins at the interface of homologous recombinational repair (HR) and nonhomologous end-joining (NHEJ) modulate DNA double-strand break (DSB) repair fidelity. Defects in HR and NHEJ proteins are linked to cancer predisposition. DSBs are key DNA lesions produced by genotoxic chemicals and radiation, and DSBs may arise spontaneously during DNA replication. HR and NHEJ compete for the repair of DSBs, and the genetic consequences of the two repair pathways are significantly different. Many factors are likely to influence the choice between HR and NHEJ, some of which are substrate-dependent. Perhaps more important from the standpoint of potential targets for chemo- or radiotherapeutic intervention in cancer treatment are trans factors, i.e., DNA repair proteins, including their concentrations, physical interactions, and biochemical activities. HR and NHEJ may compete passively for DSBs, with each operating independently of the other. Alternatively, competition may be active, with HR proteins interacting with, and modulating the activities of NHEJ proteins, and vice versa. Although most DSB repair proteins have been assigned to the HR or the NHEJ pathway, some influence both pathways, such as the MRE11/RAD50/NBS1 (MRN) complex. Recent evidence indicates that DNAPKcs and Ku are also at the NHEJ/HR interface. These proteins therefore play important roles in determining the genetic consequences of DSB damage. Other data indicate that DNA-PKcs, Ku, and MRN also regulate spontaneous HR, suggesting another mechanism by which these proteins regulate genome stability. Our central hypothesis is that proteins at the HR/NHEJ interface regulate genome stability by controlling the relative levels and outcomes of NHEJ and HR during DSB repair, and by controlling spontaneous FIR levels. We will determine how DSB repair is regulated by DNA-PKcs (Aim 1), Ku (Aim 2), MRN (Aim 3), and we will determine if spontaneous HR is regulated by these proteins (Aim 4). These projects will provide insight into the regulation of mammalian DSB repair and spontaneous HR that can be exploited to develop more effective agents to sensitize tumor cells to DNA damaging agents, and thereby improve cancer therapy.

描述（由申请人提供）：拟议研究的目标是确定同源重组修复（HR）和非同源末端连接（NHEJ）界面上的蛋白质如何调节DNA双链断裂（DSB）修复保真度。 HR 和 NHEJ 蛋白的缺陷与癌症易感性有关。 DSB 是由基因毒性化学物质和辐射产生的关键 DNA 损伤，DSB 可能在 DNA 复制过程中自发产生。 HR和NHEJ竞争DSB的修复，两种修复途径的遗传后果显着不同。许多因素可能会影响 HR 和 NHEJ 之间的选择，其中一些因素依赖于底物。从癌症治疗中化学或放射治疗干预的潜在目标的角度来看，更重要的可能是反式因子，即 DNA 修复蛋白，包括它们的浓度、物理相互作用和生化活性。 HR 和 NHEJ 可能会被动地竞争 DSB，彼此独立运作。或者，竞争可能是活跃的，HR 蛋白与 NHEJ 蛋白相互作用并调节 NHEJ 蛋白的活性，反之亦然。尽管大多数 DSB 修复蛋白已被分配到 HR 或 NHEJ 通路，但有些蛋白会影响这两条通路，例如 MRE11/RAD50/NBS1 (MRN) 复合体。最近的证据表明 DNAPKcs 和 Ku 也位于 NHEJ/HR 界面。因此，这些蛋白质在确定 DSB 损伤的遗传后果方面发挥着重要作用。其他数据表明 DNA-PKcs、Ku 和 MRN 也调节自发 HR，这表明这些蛋白质调节基因组稳定性的另一种机制。我们的中心假设是，HR/NHEJ 界面上的蛋白质通过控制 DSB 修复过程中 NHEJ 和 HR 的相对水平和结果以及控制自发的 FIR 水平来调节基因组稳定性。我们将确定 DSB 修复如何受 DNA-PKcs（目标 1）、Ku（目标 2）、MRN（目标 3）调节，并且我们将确定自发 HR 是否受这些蛋白质调节（目标 4）。这些项目将深入了解哺乳动物 DSB 修复和自发 HR 的调节，可用于开发更有效的药物，使肿瘤细胞对 DNA 损伤剂敏感，从而改善癌症治疗。