质粒介导的酵母重组诱导
Plasmid-mediated induction of recombination in yeast.
作者信息
Silberman R, Kupiec M
机构信息
Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv, Israel.
出版信息
Genetics. 1994 May;137(1):41-8. doi: 10.1093/genetics/137.1.41.
Diploid yeast cells heteroallelic at the HIS3 locus were transformed with a minichromosome (centromeric plasmid) carrying homology to the HIS3 region and containing the same two mutations as were present in the chromosomes. When a double-strand break (DSB) was introduced in the region of homology, an increase in the recombination frequency between heteroalleles (leading to His+ cells) was observed, although the plasmid was unable to donate wild-type information. This induction of recombination was dependent on the presence of homology between the plasmid sequences and the chromosomes. We show evidence for the physical involvement of the plasmid in tripartite recombination events, and we propose models that can explain the interactions between the plasmid-borne and chromosomal-borne alleles. Our results suggest that the mitotic induction of recombination by DNA damage is due to localized initiation of recombination events, and not to a general induction of recombination enzymes in the cell.
在 HIS3 位点具有杂合等位基因的二倍体酵母细胞用一个携带与 HIS3 区域同源性且含有与染色体上相同的两个突变的微型染色体（着丝粒质粒）进行转化。当在同源区域引入双链断裂（DSB）时，观察到杂合等位基因之间的重组频率增加（导致 His+细胞），尽管该质粒无法提供野生型信息。这种重组的诱导依赖于质粒序列与染色体之间同源性的存在。我们展示了质粒在三方重组事件中物理参与的证据，并提出了可以解释质粒携带和染色体携带的等位基因之间相互作用的模型。我们的结果表明，DNA 损伤对重组的有丝分裂诱导是由于重组事件的局部起始，而不是细胞中重组酶的普遍诱导。
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