Gottlieb S, Wagstaff J, Esposito R E
Department of Molecular Genetics and Cell Biology, University of Chicago, IL 60637.
Proc Natl Acad Sci U S A. 1989 Sep;86(18):7072-6. doi: 10.1073/pnas.86.18.7072.
This study shows that RAD50, a yeast DNA repair gene required for meiotic interchromosomal exchange between homologs, also is required for meiotic intrachromosomal recombination. However, only intrachromosomal events in nonribosomal DNA are dependent on RAD50; those in ribosomal DNA (rRNA-encoding DNA) occur in the absence of this gene. Furthermore, nonribosomal DNA sequences retain their RAD50-dependence even when inserted into the ribosomal DNA array. We argue that these data provide evidence for at least two pathways of meiotic intrachromosomal recombination whose activity depends on the specific sequences involved or their structural context in the chromosome. In contrast to its role in meiosis, RAD50 is not required for either inter- or intrachromosomal spontaneous mitotic recombination.
本研究表明，RAD50是酵母中同源染色体减数分裂染色体间交换所需的DNA修复基因，也是减数分裂染色体内重组所必需的。然而，只有非核糖体DNA中的染色体内事件依赖于RAD50；核糖体DNA（编码rRNA的DNA）中的那些事件在该基因缺失的情况下也会发生。此外，即使非核糖体DNA序列插入到核糖体DNA阵列中，它们仍保持对RAD50的依赖性。我们认为，这些数据为减数分裂染色体内重组的至少两条途径提供了证据，其活性取决于所涉及的特定序列或它们在染色体中的结构背景。与它在减数分裂中的作用相反，RAD50对于染色体间或染色体内的自发有丝分裂重组都不是必需的。
