Regulation of the DNA damage response by the Mre11 complex

这项将功绩奖延长五年的请求继续利用以前在这笔赠款的支持下开发的老鼠模型。在证明了依赖于Mre11复合体的DNA损伤反应可以减轻氧化和癌基因诱导的遗传毒性应激的致癌潜力后，我们将重点关注癌基因激活引起的DNA警报类型(S)。同样基于上次综述以来的发现，我们将检查Mre11复合体与BRCA1和lnk4a-p19Arf之间的遗传相互作用。我们将通过研究Ku异源二聚体和DNA双链断裂末端Mre11复合体的相互作用来扩展我们对DNA修复的分析，测试参与氧化损伤处理的酶的假设，例如那些由电离辐射和仿射化合物引起的损伤，提高HR和NHEJ的效率。针对这一问题，已经建立了酵母菌和小鼠模型。最后，我们继续关注DNA损伤信号和ATM激活的机制，通过分析其中Mre11相互作用界面发生变化的NBS1突变体。这些小鼠，Nbs1 MID小鼠，在几个方面都是独一无二的，并提供了新的背景，可以在其中阐明DNA损伤信号的机制。作为对这一努力的补充，我们还将定义最小Nbs1来测试这样的假设，即Mre11二聚体界面的调制是Nbs1的关键功能，并且ATM的激活至少部分由Mre11上的蛋白质结构域介导。鉴于Mre11复合体在肿瘤抑制、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非常重要的意义，有可能阐明Mre11复合体对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.