Alani E, Padmore R, Kleckner N
Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, Massachusetts 02138.
Cell. 1990 May 4;61(3):419-36. doi: 10.1016/0092-8674(90)90524-i.
The RAD50 gene of S. cerevisiae is required during meiosis for both recombination and chromosome synapsis and is also required for repair of double strand breaks during vegetative growth. We present below the isolation and analysis of several types of rad50 mutants. We show that null mutations block both meiotic recombination and formation of synaptonemal complex (SC) at early stages, while nonnull mutations block both processes at intermediate stages. These observations suggest that recombination and SC formation involve a series of intimately related events. Furthermore, all rad50 mutants block formation of tripartite SC structure but permit other aspects of SC development, i.e., formation of axial cores. In light of this and other observations, the meiotic and mitotic defects of rad50 mutants can be accounted for economically by the proposal that meiotic recombination, meiotic chromosome pairing, and vegetative DNA repair all use a common chromosomal homology search that involves RAD50 function.
酿酒酵母的RAD50基因在减数分裂期间对于重组和染色体联会是必需的，在营养生长期间对于双链断裂的修复也是必需的。我们在下面展示了几种类型的rad50突变体的分离和分析。我们表明，无效突变在早期阶段阻断减数分裂重组和联会复合体（SC）的形成，而非无效突变在中期阶段阻断这两个过程。这些观察结果表明，重组和SC形成涉及一系列密切相关的事件。此外，所有rad50突变体阻断三联体SC结构的形成，但允许SC发育的其他方面，即轴芯的形成。鉴于此及其他观察结果，rad50突变体的减数分裂和有丝分裂缺陷可以通过如下提议得到经济的解释：减数分裂重组、减数分裂染色体配对和营养DNA修复都使用涉及RAD50功能的共同染色体同源性搜索。
