Regulation of the DNA damage response by the Mre11 complex

这项将MERIT奖延长5年的请求继续利用先前在该资助下开发的小鼠模型。已经证明Mre11复合体依赖的DNA损伤反应减轻了氧化和致癌基因诱导的基因毒性应激的致癌潜力，我们将重点关注致癌基因激活引起的DNA报警的类型。同样基于上次综述以来获得的发现，我们将研究Mre11复合物与Brca1和lnk4a-p19Arf之间的遗传相互作用。我们将通过检查Ku异源二聚体和Mre11复合物在DNA双链断裂端的相互作用来扩展我们对DNA修复的分析，验证参与氧化损伤处理的酶（如电离辐射和拟辐射化合物引起的氧化损伤）提高HR和NHEJ效率的假设。为此，我们建立了酵母和小鼠模型。最后，我们通过分析Mre11相互作用界面改变的NBS1突变体，继续关注DNA损伤信号传导和ATM激活的机制。这些小鼠，Nbs1 mid小鼠，在几个方面是独特的，并提供了新的背景，其中DNA损伤信号传导机制可以被照亮。为了补充这项工作，我们还将定义最小的Nbs1来验证Mre11二聚体界面的调节是Nbs1的关键功能的假设，以及Mre11上的蛋白质结构域至少部分介导ATM激活的假设。鉴于Mre11复合物在肿瘤抑制、减数分裂和免疫系统发育中的重要性，本文提出的研究计划具有重要意义，有可能阐明Mre11复合物在DNA损伤反应网络的多个方面的功能影响。

This request for a five year extension of the MERIT award continues to exploit mouse models previously developed under the auspices of this grant. Having demonstrated that Mre11 complex-dependent DNA damage responses mitigate the oncogenic potential of oxidative and oncogene induced genotoxic stress, we will focus on the type(s) of DNA alerations that ensue from oncogene activation. Also based on findings obtained since the last review, we will examine genetic interactions between the Mre11 complex and Brca1 and lnk4a-p19Arf. We will extend our analysis of DNA repair at by examining the interplay of the Ku heterodimer and the Mre11 complex at DNA double strand breaks ends, testing the hypothesis that the enzymes involved in the processing of oxidative lesions such as those caused by ionizing radiation and radiomimetic compounds enhance the efficiency of both HR and NHEJ. For this issue, yeast and mouse models have been established. Finally, we continue our focus on the mechanisms of DNA damage signaling and ATM activation through the analysis of NBS1 mutants in which the Mre11 interaction interface is altered. These mice, Nbs1 mid mice, are unique in several respects and provide novel context in which mechanisms of DNA damage signaling can be illuminated. Complementing this effort, we will also define the minimal Nbs1 to test the hypothesis that modulation of the Mre11 dimer interface is the the critical function of Nbs1, · and that ATM activation is at least partially mediated by protein domains on Mre11. Given the importance of the Mre11 complex in tumor suppression, meiosis, and development of the immune system, the research program proposed herein is highly significant with the potential to illuminate the functional impact of the Mre11 complex on multiple aspects of the DNA damage response network.