Morita T, Yoshimura Y, Yamamoto A, Murata K, Mori M, Yamamoto H, Matsushiro A
Department of Microbial Genetics, Osaka University, Japan.
Proc Natl Acad Sci U S A. 1993 Jul 15;90(14):6577-80. doi: 10.1073/pnas.90.14.6577.
Analysis of mitotic and meiotic recombination in mammalian cells has been hampered by the complexity of the reactions involved as well as lack of mutants. Furthermore, none of the genes involved in the process has yet been identified. In budding yeast, Saccharomyces cerevisiae, the RAD51 gene is essential along with other genes of the RAD52 epistasis group for mitotic and meiotic recombination and DNA repair. The Rad51 protein is structurally similar to Escherichia coli RecA protein, which is required in homologous recombination and SOS responses in bacteria. Here we report the isolation of a mouse homolog of the yeast RAD51 gene. The amino acid sequence predicted from the gene shows 83% and 55% homology with those of the yeast RAD51 and the E. coli recA product, respectively. The mouse gene complemented a rad51 mutation of S. cerevisiae with sensitivity to methyl-methanesulfonate, which produces double-strand breaks of DNA. This gene is expressed in the thymus, testis, ovary, spleen, and intestine, suggesting that its product is involved in mitotic and meiotic recombination in addition to DNA repair.
哺乳动物细胞有丝分裂和减数分裂重组的分析一直受到相关反应复杂性以及缺乏突变体的阻碍。此外，该过程中涉及的基因尚未被鉴定出来。在芽殖酵母酿酒酵母中，RAD51基因与RAD52上位性组的其他基因对于有丝分裂和减数分裂重组以及DNA修复至关重要。Rad51蛋白在结构上与大肠杆菌RecA蛋白相似，后者在细菌的同源重组和SOS反应中是必需的。在此，我们报告了酵母RAD51基因小鼠同源物的分离。从该基因预测的氨基酸序列与酵母RAD51和大肠杆菌recA产物的氨基酸序列分别具有83%和55%的同源性。该小鼠基因弥补了酿酒酵母对甲磺酸甲酯敏感的rad51突变，甲磺酸甲酯会产生DNA双链断裂。该基因在胸腺、睾丸、卵巢、脾脏和肠道中表达，这表明其产物除了参与DNA修复外，还参与有丝分裂和减数分裂重组。
