Understanding the role of RAD51C complexes in recombination and repair

描述(由申请人提供)：修复DNA断裂的功能机制是维持基因组完整性和防止肿瘤发生所必需的。为了从机制上深入了解哺乳动物细胞中复杂的DNA断裂修复网络，识别修复事件每一步所需的新因素是至关重要的。同样，我们需要确定已知的DNA断裂修复蛋白的作用，如RAD51 Paralog，因为这些蛋白的突变与癌症风险增加和癌症患者在细胞毒治疗后生存率下降有关。在此之前，我们发现两个RAD51类似物，RAD51C和XRCC3，是Holliday连接解决体的重要组成部分，这是DNA断裂修复过程中分离连接的染色体所必需的复合体。这一发现不仅表明RAD51C和XRCC3在重组后期发挥了新的作用，而且还在处理停滞的复制叉子中发挥了作用。此外，我们的研究还表明RAD51C复合体与ERCC1和RecQ解旋酶的功能相互作用，这两种作用对于处理重组中间体和停滞的复制分叉都是重要的。我们的目标是定义RAD51C复合体在重组修复中的这些独特功能，这可能解释它们在基因组维护和发育中的重要性。具体目标是：(1)鉴定和鉴定重组修复中新的RAD51C相互作用蛋白。(2)RAD51C复合体与ERCC1的功能关系分析。(3)RAD51C复合体与RecQ蛋白功能关系的生化分析。公共卫生相关性：我们的研究目标是了解修复受损DNA的复杂机制，因为基因组完整性的丧失会导致细胞转化和癌症发展。我们对DNA修复蛋白的详细了解对于开发可与放射治疗或化疗联合使用的药物也至关重要，因为抑制肿瘤细胞的DNA损伤修复将使它们更容易受到治疗，从而使癌症治疗更有效。

DESCRIPTION (provided by applicant): A functional machinery to repair DNA breaks is required for maintaining genome integrity and preventing tumourigenesis. In order to gain mechanistic insights into the complex DNA break repair network in mammalian cells, it is critical to identify novel factors that are required for each steps of the repair event. Equally, we need to define the roles of the known DNA break repair proteins, such as the RAD51 paralogs, as mutations in these proteins have been associated with increased cancer risks and decreased survival of cancer patients after cytotoxic therapies. Previously, we identified two of the RAD51 paralogs, RAD51C and XRCC3, as the essential components of Holliday junction resolvasome, a complex required for separate linked chromosomes during DNA break repair. This finding not only indicates a novel role of RAD51C and XRCC3 at the late stage of recombination but also in processing stalled replication forks. In addition, our studies also suggest functional interactions of the RAD51C complexes with ERCC1 and the RECQ helicases, both of which were important for processing recombination intermediates and stalled replication forks. Our goal is to define these unique functions of RAD51C complexes in recombinational repair that may explain their importance in genome maintenance and development. The Specific Aims are: (1) Identification and characterization of novel RAD51C-interacting proteins in recombinational repair. (2) Analysis of the functional relationship between RAD51C complexes and ERCC1. (3) Biochemical analysis of the functional relationship between RAD51C complexes and the RECQ proteins. Public Health Relevance: Our research goal is to understand the complex mechanisms that repair damaged DNA, because loss of genome integrity can lead to cell transformation and cancer development. Our detailed knowledge of DNA repair proteins is also crucial for developing drugs that can be used in combination with radiotherapy or chemotherapy, since the inhibition of DNA damage repair in tumor cells would make them more susceptible to therapy, thus allowing more efficient treatment of cancer.