Saccharomyces cerevisiae recA homologues RAD51 and DMC1 have both distinct and overlapping roles in meiotic recombination
Saccharomyces cerevisiae recA homologues RAD51 and DMC1 have both distinct and overlapping roles in meiotic recombination
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DOI：
10.1046/j.1365-2443.1997.1480347.x
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发表时间：
1997-10-01
期刊：
影响因子：
2.1
通讯作者：
Bishop, DK
中科院分区：
文献类型：
--
作者：
Shinohara, A;Gasior, S;Bishop, DK
背景：Rad51和Dmc1是大肠杆菌（Escherichia coli）重组蛋白RecA的酿酒酵母（Saccharomyces cerevisiae）同源物。突变分析表明，这两种蛋白对于正常的减数分裂重组、联会复合体的及时有效形成以及减数分裂前期的正常进展都是必需的。
结果：我们进一步对rad51和dmc1单突变体进行了表征。dmc1突变在双链断裂（DSB）修复、交换重组和减数分裂进展方面比rad51突变体具有更严重的缺陷；相反，在恢复生长过程中，rad51突变在生存能力和染色体内重组方面比dmc1突变具有更严重的缺陷。对rad51 dmc1双突变体以及单突变体的分析表明，双突变体在减数分裂过程中交换形成方面存在更多缺陷，并且尤其显著的是，在恢复生长过程中在同源染色体间和染色体内重组方面存在更多缺陷。与在rad51突变体中观察到的依赖DMC1的重组一致，在该突变体中首次检测到Dmc1蛋白的亚核复合物。与对重组的影响相反，双突变体对减数分裂进展的影响与rad51单突变体相似。
结论：Rad51和Dmc1各自对减数分裂重组有独特贡献。然而，这两种蛋白在某些情况下能够相互替代，这意味着它们很可能至少共享一种重组功能。重组和细胞周期表型都与dmc1突变比rad51突变使双链断裂后重组复合物在更晚、更稳定的阶段停滞的可能性一致。
Background: Rad51 and Dmc1 are Saccharomyces cerevisiae homologues of the Escherichia roll recombination protein RecA. Mutant analysis has shown that both proteins are required for normal meiotic recombination, for timely and efficient formation of synaptonemal complex and for normal progression out front meiotic prophase.Results: We have further characterized rad51 and dmc1 single mutants, A dmc1 mutation confers more severe defects in double strand break (DSB) resolution, crossover recombination and meiotic progression than does a rad51 mutant; in contrast, during return to growth, a rad51 mutation confers more severe defects ill viability and intrachromosomal recombination than does a dmc1 mutation. Analysis of a rad51 dmc1 double mutant, in parallel with single mutants, shows that the double mutant is more defective with respect to the formation of crossovers during meiosis and, especially strikingly, with respect to interhomologue and intrachromosomal recombination during return to growth, Consistent with the observation of DMC1-dependent recombination in a rad51 mutant, subnuclear complexes of Dmc1 protein were detected for the first time in this mutant. In contrast to the effects on recombination, the effect of the double mutant on meiotic progression was similar to that of the rad51 single mutant.Conclusion: Rad51 and Dmc1 each make unique contributions to meiotic recombination, However, the two proteins are capable of substituting for one another under some circumstances, implying that they most likely share at least one recombination function, Recombination and cell cycle phenotypes are all consistent with the possibility that a dmc1 mutation causes an arrest of the post-DSB recombination complexes at a later, more stable stage than does a rad51 mutation.