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>The STRUCTURAL MAINTENANCE OF CHROMOSOMES 5/6 Complex Promotes Sister Chromatid Alignment and Homologous Recombination after DNA Damage in Arabidopsis thaliana
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The STRUCTURAL MAINTENANCE OF CHROMOSOMES 5/6 Complex Promotes Sister Chromatid Alignment and Homologous Recombination after DNA Damage in Arabidopsis thaliana
n nnnSister chromatids are often arranged as incompletely alignedentities in interphase nuclei of Arabidopsis thaliana. The STRUCTURALMAINTENANCE OF CHROMOSOMES (SMC) 5/6 complex, together withcohesin, is involved in double-strand break (DSB) repair bysister chromatid recombination in yeasts and mammals. Here,we analyzed the function of genes in Arabidopsis. The wild-typeallele of SMC5 is essential for seed development. Each of thetwo SMC6 homologs of Arabidopsis is required for efficient repairof DNA breakage via intermolecular homologous recombinationin somatic cells. Alignment of sister chromatids is enhancedtransiently after X-irradiation (and mitomycin C treatment)in wild-type nuclei. In the smc5/6 mutants, the x-ray–mediatedincrease in sister chromatid alignment is much lower and delayed.The reduced S phase–established cohesion caused by a knockoutmutation in one of the -kleisin genes, SYN1, also perturbedenhancement of sister chromatid alignment after irradiation,suggesting that the S phase–established cohesion is aprerequisite for correct DSB-dependent cohesion. The radiation-sensitive51mutant, deficient in heteroduplex formation during DSB repair,showed wild-type frequencies of sister chromatid alignment afterX-irradiation, implying that the irradiation-mediated increasein sister chromatid alignment is a prerequisite for, ratherthan a consequence of, DNA strand exchange between sister chromatids.Our results suggest that the SMC5/6 complex promotes sisterchromatid cohesion after DNA breakage and facilitates homologousrecombination between sister chromatids.展开▼
机译:ABSTRACTn FONT> TH> TR> TABLE> n
n TOP n <字体颜色= 464c53>抽象 FONT> n 介绍 n 结果 n 讨论 n 方法 n 参考文献 n FONT> TH> TR> TABLE> n nnnSister染色单体通常排列为不完全对齐 SUP>实体拟南芥(Irabidopsis thaliana) I>相间核中的Ss。染色体(SMC)5/6复合物的结构 SUP>维护与 SUP>粘着素一起通过 SUP>参与双链断裂(DSB)修复。酵母和哺乳动物中的姐妹染色单体重组。在这里, SUP>我们分析了拟南芥 I>中基因的功能。 SMC5 I>的野生型 SUP>等位基因对于种子发育至关重要。 拟南芥 I>的两个 SMC6 I>同源物中的每一个都是通过分子间同源重组有效修复DNA断裂的 SUP> > SUP>在体细胞中。 X射线(和丝裂霉素C处理) SUP>在野生型细胞核中后,姐妹染色单体的排列会暂时得到增强。在 smc5 I> / 6 I>突变体中,X射线介导的 SUP>姐妹染色单体比对的增加要低得多且延迟。 SUP>由之一中的敲除 SUP>突变引起的降低的S相建立的内聚力-kleisin基因, SYN1 I>,在辐照后也会干扰姐妹染色单体排列的 SUP>增强, SUP>提示S期建立的内聚力是 SUP>正确依赖DSB的内聚性的先决条件。在DSB修复过程中缺乏异源双链形成的辐射敏感51 I> SUP>突变体, SUP>显示了 后的姐妹染色单体比对的野生型频率。 SUP> X辐照,这意味着姐妹染色单体之间DNA链交换的结果是辐照介导的姐妹染色单体比对的增加 SUP>的先决条件。 SUP> SUP> SUP>我们的结果表明,SMC5 / 6复合物可促进DNA断裂后的姐妹 SUP>染色单体凝聚力,并促进姐妹染色单体之间的同源 SUP>重组。 SUP >
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