Conservative repair of a chromosomal double-strand break by single-strand DNA through two steps of annealing
Conservative repair of a chromosomal double-strand break by single-strand DNA through two steps of annealing
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DOI：
10.1128/mcb.00672-06
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发表时间：
2006-10-01
影响因子：
5.3
通讯作者：
Resnick, Michael A.
中科院分区：
文献类型：
--
作者：
Storici, Francesca;Snipe, Joyce R.;Resnick, Michael A.
染色体双链断裂（DSB）的修复是细胞正常生长所必需的，同源重组是DSB修复的普遍过程。我们使用与DSB两侧具有同源性的单链寡核苷酸探索了酵母酿酒酵母中的DSB修复机制。寡核苷酸定向修复仅通过Rad52和Rad59介导的单链退火（SSA）发生。甚至人Rad52的SSA结构域也为无效rad52突变提供部分互补。修复不涉及Rad51驱动的链侵入，而且链侵入的抑制增加了寡核苷酸的修复。DSB显示出以链偏向的方式激活与断裂的仅一侧同源的寡核苷酸的靶向，所述寡核苷酸与断裂的大距离（至少20 kb）处的断裂同源，这表明广泛的5'至3'切除，然后将切除的DNA恢复到双链状态。我们的结论是，长切除的染色体DSB末端修复的单链DNA寡核苷酸通过两轮退火。单链DNA的修复可以是保守的，并且可以允许精确恢复具有紧密间隔的DSB的染色体DNA。
The repair of chromosomal double-strand breaks (DSBs) is essential to normal cell growth, and homologous recombination is a universal process for DSB repair. We explored DSB repair mechanisms in the yeast Saccharomyces cerevisiae using single-strand oligonucleotides with homology to both sides of a DSB. Oligonucleotide-directed repair occurred exclusively via Rad52- and Rad59-mediated single-strand annealing (SSA). Even the SSA domain of human Rad52 provided partial complementation for a null rad52 mutation. The repair did not involve Rad51-driven strand invasion, and moreover the suppression of strand invasion increased repair with oligonucleotides. A DSB was shown to activate targeting by oligonucleotides homologous to only one side of the break at large distances (at least 20 kb) from the break in a strand-biased manner, suggesting extensive 5' to 3' resection, followed by the restoration of resected DNA to the double-strand state. We conclude that long resected chromosomal DSB ends are repaired by a single-strand DNA oligonucleotide through two rounds of annealing. The repair by single-strand DNA can be conservative and may allow for accurate restoration of chromosomal DNAs with closely spaced DSBs.