MOLECULAR MECHANISMS OF DNA REPAIR IN YEAST AND THEIR ROLE IN MEIOSIS

酵母有丝分裂细胞中的DNA修复系统 酿酒酵母正被检测其保护作用 以及相应基因的作用 在正常的减数分裂中。 RAD50、RAD52和RAD57基因是必需的 修复有丝分裂细胞中的DNA双链断裂。 我们 已经证明它们也是减数分裂所必需的。 突变 破坏正常的减数分裂重组; RAD 50在减数分裂早期起作用。 在rad52和rad53中观察到罕见的单链中断（SSI）。 rad57菌株似乎与重组有关， 已经被定性。 基于基因和生化变化， 基因功能的顺序似乎是RAD 50、RAD 52和RAD 57。 鉴于RAD 52在修复和重组中的重要作用， 我们已经开始研究其在正常情况下的功能， DNA代谢和随后的DNA损伤剂治疗。 这是通过"结构域映射"的功能区域， RAD52基因 受RAD 52影响的进程包括 生长、重组、诱变、必需yNUCR的控制 基因，控制减数分裂中的链交换蛋白水平，减数分裂 细胞活力、复制后修复和DNA链断裂 在减数分裂中。 突变是在体外产生的， 基因正在被转移到基因组中。 后果是 以上基因功能正在研究中。 此外， 正在研究基因和突变体与基因剂量的关系 利用这个实验室开发的一个系统， 不同数量的基因。

DNA repair systems identified in mitotic calls of the yeast Saccharomyces cerevisiae are being examined for their protection of cells undergoing meiosis and the role of the corresponding genes in normal meiosis. The RAD50, RAD52 and RAD57 genes are essential in the repair of DNA double-strand breaks in mitotic cells. We have shown that they are also required for meiosis. Mutations abolish normal meiotic recombination; RAD50 acts early in meiosis. Rare single-strand interruptions (SSIs) are observed in rad52 and rad57 strains which appear to be related to recombination and these have been characterized. Based on genetic and biochemical changes, the order of gene function appears to be RAD50, RAD52, and RAD57. Given the important role RAD52 plays in repair and recombination, we have initiated studies to characterize its function in normal DNA metabolism and following treatment with DNA damaging agents. This is being done by "domain mapping" the functional regions of the RAD52 gene. Included among the processes affected by RAD52 are growth, recombination, mutagenesis, control of the essential yNUCR gene, control of strand exchange protein levels in meiosis, meiotic cellular viability, post replication repair, and DNA strand breaks in meiosis. Mutations are being created in vitro and the altered gene is being transplaced into the genome. The consequences to the above gene functions are being examined. In addition, the role of the gene and mutants in relation to gene dosage is being examined using a system developed in this laboratory for isolating cell lines with different numbers of the gene.