Preferential binding to branched DNA strands and strand-annealing activity of the human Rad51B, Rad51C, Rad51D and Xrcc2 protein complex.
Preferential binding to branched DNA strands and strand-annealing activity of the human Rad51B, Rad51C, Rad51D and Xrcc2 protein complex.
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DOI：
10.1093/nar/gkh578
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发表时间：
2004-04
影响因子：
14.9
通讯作者：
H. Yokoyama;Naoyuki Sarai;W. Kagawa;Rima Enomoto;T. Shibata;H. Kurumizaka;S. Yokoyama
中科院分区：
文献类型：
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作者：
H. Yokoyama;Naoyuki Sarai;W. Kagawa;Rima Enomoto;T. Shibata;H. Kurumizaka;S. Yokoyama
Rad 51 B、Rad 51 C、Rad 51 D和Xrcc 2蛋白是Rad 51旁系同源物，并且在哺乳动物细胞中形成复合物（BCDX 2复合物）。由于重组修复效率低下，任何一个Rad 51基因缺陷的突变细胞表现出自发的基因组不稳定性和对DNA损伤剂的极端敏感性。因此，Rad 51旁系同源物在通过重组修复维持基因组完整性方面发挥重要作用。在本研究中，我们研究了人BCDX 2复合物的DNA结合偏好。使用7种类型的DNA底物，单链DNA（ssDNA），双链DNA，5 '-和3'-tailed双链体，切口双链体DNA，Y形DNA和合成的霍利迪连接的竞争性DNA结合试验，揭示了BCDX 2复合物优先结合到两个具有分支结构的DNA底物（Y形DNA和合成的霍利迪连接）。此外，BCDX 2复合物催化长线性ssDNA（长度为1.2 kb）与其互补环状ssDNA之间的链退火反应。BCDX 2复合物的这些特性可能对其在维持染色体完整性中的作用很重要。
The Rad51B, Rad51C, Rad51D and Xrcc2 proteins are Rad51 paralogs, and form a complex (BCDX2 complex) in mammalian cells. Mutant cells defective in any one of the Rad51-paralog genes exhibit spontaneous genomic instability and extreme sensitivity to DNA-damaging agents, due to inefficient recombinational repair. Therefore, the Rad51 paralogs play important roles in the maintenance of genomic integrity through recombinational repair. In the present study, we examined the DNA-binding preference of the human BCDX2 complex. Competitive DNA-binding assays using seven types of DNA substrates, single-stranded DNA (ssDNA), double-stranded DNA, 5'- and 3'-tailed duplexes, nicked duplex DNA, Y-shaped DNA and a synthetic Holliday junction, revealed that the BCDX2 complex preferentially bound to the two DNA substrates with branched structures (the Y-shaped DNA and the synthetic Holliday junction). Furthermore, the BCDX2 complex catalyzed the strand-annealing reaction between a long linear ssDNA (1.2 kb in length) and its complementary circular ssDNA. These properties of the BCDX2 complex may be important for its roles in the maintenance of chromosomal integrity.