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DNA双链断裂(double-strand break,DSB)是射线等外源性因素致DNA损伤中最严重的一种类型,机体为维护基因组的完整性,可启动两种不同的途径对DSB进行修复[1]:非同源末端连接(non-homologous end joining,NHEJ)途径和同源重组(homologous recombination,HR)途径。虽然两者在修复DSB中均发挥着重要作用,但也存在着竞争和协同作用[2]。Ku70(一种NHEJ蛋白)和Rad51(一种HR修复蛋白)分别是NHEJ和HR中的重要组成蛋白。本研究以Ku70为靶点,通过调控Ku70蛋白表达水平来观察其对Rad51蛋白表达的影响,以期为研究NHEJ与HR的相互作用提供帮助。
Ku70对同源重组修复蛋白Rad51的调节作用
Regulation of homologous recombination repair protein Rad51 by Ku70
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摘要:
目的 研究非同源末端连接(NHEJ)蛋白Ku70对同源重组(HR)修复蛋白Rad51的调节作用,初步探讨HR与NHEJ间协同作用的机制。 方法 采用Western blot法观察特异性增高和降低Ku70蛋白水平后Rad51蛋白表达水平的变化情况。 结果 靶向Ku70基因小干扰RNA(siRNA)单纯转染组Rad51蛋白的表达水平较空白对照组明显下降;Ku70高表达载体PGCsi3.0-hKu70转染肿瘤细胞后,随着Ku70表达水平的升高,Rad51水平也随之升高。 结论 Ku70可能对Rad51有正调控作用,NHEJ可能通过Ku70对Rad51的调节来实现其与HR的协同作用。 Abstract:Objective To explore the regulative effect of non-homologous end joining(NHEJ)protein Ku70 on homologous recombination repair protein Rad51, and to investigate the synergistic mechanism of homologous recombination repair in combination with NHEJ. Methods Observed Rad51 protein expression after transfect Ku70 small interfering RNA or Ku70 plasmid DNA into tumor cells using Western blot. Results Expression of Rad51 was obviously reduced after pretreated with Ku70 small interfering RNA. And with the increasing expression of Ku70 protein after transfection of Ku70 plasmid DNA PGCsi3.0-hKu70 into tumor cell lines, the Rad51 protein expression was increased. Conclusion Ku70 protein has regulating effect on gene expression of Rad51, and it might participate in the collaboration between homologous recombination repair and NHEJ. -
Key words:
- DNA repair /
- Rad51 recombinase /
- RNA, small interfering /
- Ku70
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