Arnaudeau C, Helleday T, Jenssen D
Wallenberg Laboratory, Stockholm University, Stockholm, S-106 91, Sweden.
J Mol Biol. 1999 Jun 25;289(5):1231-8. doi: 10.1006/jmbi.1999.2856.
Information concerning the function of recombination proteins in mammalian cells has been obtained from biochemical studies, but little is known about their mechanisms of action in growing cells. The eukaryotic recombination protein RAD51, a homologue of the Escherichia coli RecA protein, has been shown to interact with various proteins, including the p53 protein, the guardian of genomic stability maintenance. Here, the hamster RAD51 protein, CgRAD51, has been overexpressed in the SPD8 cell line, derived from Chinese hamster V79 cells. This cell line offers unique possibilities for studying different mechanisms for homologous recombination on endogenous substrates. We report that the SPD8 cell line contains a mutated p53 gene, which provides new insights into the recombination process in these cells. The present study demonstrates that overexpression of CgRAD51 in these cells results in a two- to threefold increase in endogenous recombination. In addition, sequence analysis indicated that RAD51 promotes homologous recombination by a chromatid exchange mechanism.
关于重组蛋白在哺乳动物细胞中的功能信息已通过生化研究获得，但对于它们在生长细胞中的作用机制却知之甚少。真核重组蛋白RAD51是大肠杆菌RecA蛋白的同源物，已被证明能与多种蛋白质相互作用，包括基因组稳定性维护的守护者p53蛋白。在此，仓鼠RAD51蛋白CgRAD51在中国仓鼠V79细胞来源的SPD8细胞系中过表达。该细胞系为研究内源性底物上同源重组的不同机制提供了独特的可能性。我们报告称，SPD8细胞系含有一个突变的p53基因，这为这些细胞中的重组过程提供了新的见解。本研究表明，CgRAD51在这些细胞中的过表达导致内源性重组增加两到三倍。此外，序列分析表明RAD51通过染色单体交换机制促进同源重组。
