Homing directed by VDE endonuclease in Saccharomyces cerevisiae

在酿酒酵母中，DNA双链断裂(DSB)有多种修复机制。非同源末端连接(NHEJ)效率在二倍体细胞中相对于单倍体细胞在有丝分裂时被下调，但这种交配型调控在减数分裂中的机制尚不清楚。当减数分裂时没有同源模板时，只有少数孢子存活。在存活孢子中，DSB可能被NHEJ修复。为了验证这一观点，我们通过VDE内切酶在减数分裂中特异性地引入了DSB。并对野生型Δ和YKU70Δ菌株的孢子活力进行了检测。与野生型相比，这些缺失突变体的孢子活力降低。可存活的孢子含有由NHEL引起的典型的DNA修复的短插入或缺失。结果表明，NHEJ在存活孢子中修复DSB，NHEJ修复DSB发生在减数分裂。

In Saccharomyces cerevisiae, DNA double strand breaks (DSBs) are repaired by several mechanisms. Non-homologous end joining (NHEJ) efficiency is down-regulated in diploid cells relative to haploid cells at mitosis, but the mechanism of this mating type regulation at meiosis is unknown. When DSBs occur without homologous, template at meiosis, a few spores survive. In survival spores, DSBs might be repaired by NHEJ. To test this idea, we introduced DSB specifically in mieiosis by VDE endonuclease. and examined spore viability in the wild-type, nejl Δ and yku70Δ strains. The spore viability of these deletion mutants reduced in comparison with wild type. The viable spores contain short insertions or deletions typical for DNA repair caused by NHEL. The results suggest that DSBs is repaired by NHEJ in survival spores and DSBs repair by NHEJ occurs at meiosis.