RAD51C
小结
RAD51C（也称为RAD51L2）编码蛋白是RAD51重组酶家族的成员，其在同源重组（HR）介导的双链DNA断裂（DSBs）中发挥作用。RAD51C与RAD51形成复合物在DSB的早期起作用：切除位于DSB断裂位点侧翼的5'端DNA链和单链突出端被RAD51包被形成核蛋白丝。RAD51C是两种DSB修复复合物的组成部分，BCDX2（包括RAD51B，RAD51C，RAD51D和XRCC2）和CX3（包括XRCC3），它们分别在RAD51细丝的损伤稳定和组装中起作用。RAD51C活性对解决Holliday连接也很重要。RAD51C的双等位基因胚系突变与一种Fanconi贫血类疾病相关，特征是发育缺陷和癌症易感性。此外，RAD5C的胚系突变更容易患乳腺癌和卵巢癌以及头颈部鳞状细胞癌。
RAD51C is infrequently mutated in human cancers; however, RAD51C gene expression was reduced in a subset of breast cancer tumor samples. RAD51C (also known as RAD51L2) is a member of the RAD51 recombinase family that functions in homologous recombination (HR)-mediated repair of double-stranded DNA breaks (DSBs). RAD51C, in complex with RAD51, acts at an early step in the DSB pathway: the 5’ended DNA strands flanking the DSB break site are resected and the single-stranded overhangs are coated by RAD51 forming a nucleo-protein filament. RAD51 then probes for homologous DNA and initiates the process of strand invasion and exchange between homologous DNA. RAD51C is a component of two DSB repair complexes, BCDX2 (including RAD51B, RAD51C, RAD51D, and XRCC2) and CX3 (including XRCC3), which have roles in damage-stabilization and assembly of RAD51 filaments, respectively. RAD51C activity is also important for resolving Holliday junctions. Biallelic germline mutations of RAD51C are associated with a Fanconi anemia-like disorder characterized by developmental defects and predisposition to cancer. In addition, germline mutations in RAD51C confer susceptibility to breast and ovarian cancer, as well as head and neck squamous cell carcinoma.