Fission yeast Swi5/Sfr1 and Rhp55/Rhp57 differentially regulate Rhp51-dependent recombination outcomes
Fission yeast Swi5/Sfr1 and Rhp55/Rhp57 differentially regulate Rhp51-dependent recombination outcomes
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DOI：
10.1038/sj.emboj.7601582
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发表时间：
2007-03-07
期刊：
影响因子：
11.4
通讯作者：
Iwasaki, Hiroshi
中科院分区：
文献类型：
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作者：
Akamatsu, Yufuko;Tsutsui, Yasuhiro;Iwasaki, Hiroshi
Rad 51（在裂殖酵母中为Rhp 51）重组酶的完全活性需要几种被称为介体的辅助蛋白。在这项研究中，我们分析了最近发现的Swi 5/Sfr 1复合体的体内功能。在正常生长的细胞中，Swi 5-GFP蛋白定位于细胞核，在那里它形成具有几个不同病灶的弥散核染色模式。这些自发灶在swi 2 δ突变体中不形成。紫外线照射后，Swi 2D突变体中Swi 5焦点形成被诱导，这是一种依赖于Sfr 1功能的反应，Sfr 1也形成与损伤诱导的Rhp 51焦点共定位的焦点。在swi 5 Delta和rhp 57 Delta突变体中，紫外线诱导的Rhp 51焦点数量部分减少，而在swi 5D rhp 57 D双突变体中则完全消失。HO核酸内切酶诱导的DNA双链断裂（DSB）产生的产物的测定表明，Rhp 51和Rhp 57，但不是Swi 5/Sfr 1，是必不可少的交叉生产。这些结果表明，Swi 5/Sfr 1的功能作为Rhp 51调解人，但处理DSB的方式不同的Rhp 55/57调解人。
Several accessory proteins referred to as mediators are required for the full activity of the Rad51 (Rhp51 in fission yeast) recombinase. In this study, we analyzed in vivo functions of the recently discovered Swi5/Sfr1 complex from fission yeast. In normally growing cells, the Swi5-GFP protein localizes to the nucleus, where it forms a diffuse nuclear staining pattern with a few distinct foci. These spontaneous foci do not form in swi2 Delta mutants. Upon UV irradiation, Swi5 focus formation is induced in swi2D mutants, a response that depends on Sfr1 function, and Sfr1 also forms foci that colocalize with damage-induced Rhp51 foci. The number of UV-induced Rhp51 foci is partially reduced in swi5 Delta and rhp57 Delta mutants and completely abolished in an swi5D rhp57D double mutant. An assay for products generated by HO endonuclease-induced DNA double-strand breaks (DSBs) reveals that Rhp51 and Rhp57, but not Swi5/Sfr1, are essential for crossover production. These results suggest that Swi5/Sfr1 functions as an Rhp51 mediator but processes DSBs in a manner different from that of the Rhp55/57 mediator.