The RADS gene product involved in the avoidance of non-homologous end-joining of DNA double strand breaks in the yeast Saccharomyces cerevisiae
The RADS gene product involved in the avoidance of non-homologous end-joining of DNA double strand breaks in the yeast Saccharomyces cerevisiae
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DOI：
10.1093/nar/25.4.743
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发表时间：
1997-02-15
影响因子：
14.9
通讯作者：
EckardtSchupp, F
中科院分区：
文献类型：
--
作者：
Ahne, F;Jha, B;EckardtSchupp, F
在野生型酵母中，穿梭载体 YpJA18 的 URA3 基因中限制性内切酶 Apal 和 Ncol 诱导的 169 bp 双链间隙的修复根据同源染色体序列以高保真度发生，相比之下，rad5-7 和 rad5 Delta 突变体中只有 25% 的细胞执行正确的间隙修复，正如连接位点测序所证明的那样，其余细胞重新环化通过连接不相容、非同源末端来形成缺口质粒，因此，关于 DNA 双链断裂的修复，rad5 突变体的行为类似于哺乳动物细胞而不是芽殖酵母，大多数末端连接的质粒完全缺失限制性末端的 3' 和 5' 突出单链中的一个或两个，并经历了伴随填充 DNA 合成的平端连接，这些结果意味着 Rad5 蛋白的重要作用(Rad5p) 保护突出的单链末端并避免在芽殖酵母修复双链间隙期间出现非同源末端连接；或者，Rad5p可能是提高酵母同源重组效率的辅助因素，然而，Rad5p功能的分子机制需要进一步研究。
In wild-type yeast, the repair of a 169 bp double-strand gap induced by the restriction enzymes Apal and Ncol in the URA3 gene of the shuttle vector YpJA18 occurs with high fidelity according to the homologous chromosomal sequence, In contrast, only 25% of the cells of rad5-7 and rad5 Delta mutants perform correct gap repair, As has been proven by sequencing of the junction sites, the remaining cells recircularise the gapped plasmids by joining of the non-compatible, non-homologous ends, Thus, regarding the repair of DNA double-strand breaks, the rad5 mutants behave like mammalian cells rather than budding yeast, The majority of the end joined plasmids miss either one or both of the 3' and 5' protruding single-strands of the restriction ends completely and have undergone blunt-end ligation accompanied by fill-in DNA synthesis, These results imply an important role for the Rad5 protein (Rad5p) in the protection of protruding single-strand ends and for the avoidance of non-homologous end joining during repair of double-strand gaps in budding yeast; Alternatively, the Rad5p may be an accessory factor increasing the efficiency of homologous recombination in yeast, however, the molecular mechanism of Rad5p function requires further investigation.