Double-strand break repair in mammalian cells

强大的细胞修复途径通过消除或减少基因改变来维持基因组的完整性 在DMA损坏后。在这种通路不存在或出现故障的情况下，健康受到损害， 个人可能是癌症的易感人群。双链断裂(DSB)是一种特别有害的DMA 损坏。DSB在正常的DMA代谢和之后的染色体中自发发生 暴露于外源DNA损伤剂，如电离辐射。我们已经证明了一个 参与DSB修复的主要途径是同源重组(HR)。在人力资源中，未损坏的 同源序列模板修复断裂的染色体，使其成为一种精确的修复类型。 这项拟议的研究侧重于了解促进哺乳动物细胞中HR的因素以及 人力资源受损对机体健康的影响。具体目标1是结构-功能分析 肿瘤抑制基因BRCA2及其在促进小鼠细胞存活、心率和组织存活中的作用。 BRCA2 DNA结合域的各个亚域的作用是特别强调的。在……里面 此外，还将调查几个患者突变的作用。在具体目标2中，蜂窝要求 对于BRCA2和其他HR突变细胞中的HR校正，将进行研究。我们的初步分析表明 BRCA2在HR中的功能是将RAD51链交换蛋白运送到单链DNA。 提出了用实验来检验和扩展这一假说。具体目标3是调查 小鼠对HR因子的依赖性。HR严重缺乏的小鼠在胚胎发育过程中过早死亡， 尽管有不那么严重缺陷的小鼠在发育过程中取得了进一步的进步，或者是存活的。要理解 HR因子在小鼠中的依赖性和揭示作用，我们将分析携带突变的小鼠 在人力资源因素的组合中。编码RAD51 Paralog(XRCC2)和其他RAD52基因的作用 上位性组成员(RAD52和RAD54)以及下构型BRCA2的成员将被调查 等位基因。

Robust cellular repair pathways maintain genomic integrity by eliminating or reducing genetic alterations following DMA damage. In the absence or malfunction of such pathways, health is compromised and individuals can be cancer-prone. Double-strand breaks (DSBs) are a particularly injurious type of DMA damage. DSBs occur spontaneously in chromosomes as a result of normal DMA metabolism and after exposure to exogenous DNA damaging agents, such as ionizing radiation. We have demonstrated that a major pathway involved in DSB repair is homologous recombination (HR). In HR, an undamaged homologous sequence templates the repair of the broken chromosome, making it a precise type of repair. The proposed research focuses on understanding the factors that promote HR in mammalian cells and the consequences of impaired HR on organismal health. Specific aim 1 is a structure-function analysis of the tumor suppressor BRCA2 and its role in promoting cell survival, HR, and organismal viability in the mouse. There is a specific emphasis on the role of various subdomains of the BRCA2 DNA binding domain. In addition, the role of several patient mutations will be investigated. In specific aim 2 the cellular requirements for HR correction in Brca2 and other HR mutant cells will be investigated. Our preliminary analysis indicates that the function of BRCA2 in HR is to deliver the Rad51 strand exchange protein to single-stranded DNA. Experiments are proposed to test and extend this hypothesis are proposed. Specific aim 3 is to investigate the dependence on HR factors in the mouse. Mice with severe HR deficiency die early in embryogenesis, although mice with less severe deficiencies progress further in development or are viable. To understand the dependencies and uncover roles for HR factors in the mouse, we will analyze mice that carry mutations in combinations of HR factors. The roles of a gene encoding a Rad51 paralog (Xrcc2) and other Rad52 epistasis group members (Rad52 and Rad54) will be investigated, as well as that of a hypomorphic Brca2 allele.