Chromosome instability and defective recombinational repair in knockout mutants of the five Rad51 paralogs
Chromosome instability and defective recombinational repair in knockout mutants of the five Rad51 paralogs
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DOI：
10.1128/mcb.21.8.2858-2866.2001
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发表时间：
2001-04-01
影响因子：
5.3
通讯作者：
Takeda, S
中科院分区：
文献类型：
--
作者：
Takata, M;Sasaki, MS;Takeda, S
Rad 51蛋白是大肠杆菌RecA的真核同源物，在酿酒酵母的有丝分裂和减数分裂同源DNA重组（HR）中起着核心作用，并且对脊椎动物细胞的增殖至关重要。五个脊椎动物基因，RAD 51 B，-C，和-D和XRCC 2和-3，涉及HR的基础上，它们的序列相似性Rad 51（Rad 51旁系同源物）。我们在鸡B淋巴细胞DT 40细胞系中产生了这些蛋白质中的每一种缺陷的突变体，并在这里报告了四种新的突变体及其互补衍生物与我们以前报道的rad 51 b突变体的比较。通过靶向整合和姐妹染色单体交换测量，Rad 51旁核突变均损害HR。值得注意的是，突变体细胞系都表现出非常相似的表型：自发染色体畸变，对交联剂（丝裂霉素C和顺铂）杀伤的高敏感性，对γ射线的轻度敏感性，以及暴露于γ射线后重组修复过程中Rad 51病灶形成的显着减弱。此外，所有的突变体显示部分校正的抗DNA损伤的过表达的人Rad 51。我们的结论是，Rad 51旁系同源参与修复作为一个功能单位，促进行动Rad 51在HR。
The Rad51 protein, a eukaryotic homologue of Escherichia coli RecA, plays a central role in both mitotic and meiotic homologous DNA recombination (HR) in Saccharomyces cerevisiae and is essential for the proliferation of vertebrate cells. Five vertebrate genes, RAD51B, -C, and -D and XRCC2 and -3, are implicated in HR on the basis of their sequence similarity to Rad51 (Rad51 paralogs). We generated mutants deficient in each of these proteins in the chicken B-lymphocyte DT40 cell line and report here the comparison of four new mutants and their complemented derivatives with our previously reported rad51b mutant. The Rad51 paralog mutations all impair HR, as measured by targeted integration and sister chromatid exchange. Remarkably, the mutant cell lines all exhibit very similar phenotypes: spontaneous chromosomal aberrations, high sensitivity to killing by cross-linking agents (mitomycin C and cisplatin), mild sensitivity to gamma rays, and significantly attenuated Rad51 focus formation during recombinational repair after exposure to gamma rays. Moreover, all mutants show partial correction of resistance to DNA damage by overexpression of human Rad51. We conclude that the Rad51 paralogs participate in repair as a functional unit that facilitates the action of Rad51 in HR.