Visualization of DNA double-strand break repair in live bacteria reveals dynamic recruitment of Bacillus subtilis RecF, RecO and RecN proteins to distinct sites on the nucleoids
Visualization of DNA double-strand break repair in live bacteria reveals dynamic recruitment of Bacillus subtilis RecF, RecO and RecN proteins to distinct sites on the nucleoids
复制标题
DOI：
10.1111/j.1365-2958.2004.04102.x
复制
发表时间：
2004-06-01
影响因子：
3.6
通讯作者：
Graumann, PL
中科院分区：
文献类型：
--
作者：
Kidane, D;Sanchez, H;Graumann, PL
我们发现smc样的RecN蛋白、RecF和RecO蛋白参与DNA重组，在枯草芽孢杆菌DNA双链断裂（DSB）修复中起重要作用。在DNA dsb诱导下，RecN、RecO和RecF在大多数细胞中定位为一个离散焦点，而很少观察到两个或三个焦点。RecN、RecO和RecF在诱导病灶上共定位，RecN先定位，RecO后定位，RecF后定位。因此，三种修复蛋白被不同地招募到类核上的不同位置，可能构成活性DSB修复中心（rc）。在没有RecN的情况下，RecF不能形成规则的灶，在recO细胞中也不能形成任何灶，这表明RecN和recO在初始化RCs形成过程中起着核心作用。在recA、recG或recU突变细胞中检测到RecN/O/F灶，表明这些蛋白作用于突触或突触后相关蛋白的上游。在没有外源性DNA损伤的情况下，RCs很少见，但它们在recA和recU细胞中积累，这表明在没有recA或recU的情况下，dsb经常发生。结果表明，RecN在溶液中形成多聚体，在含有DSB的细胞中形成高分子量复合物，从而引发RCs的形成，RCs介导DSB与同源姐妹染色体的修复，这为原核生物DSB修复提供了一种新的概念。
We have found that SMC-like RecN protein, RecF and RecO proteins that are involved in DNA recombination play an important role in DNA double-strand break (DSB) repair in Bacillus subtilis. Upon induction of DNA DSBs, RecN, RecO and RecF localized as a discrete focus on the nucleoids in a majority of cells, whereas two or three foci were rarely observed. RecN, RecO and RecF co-localized to the induced foci, with RecN localizing first, while RecO localized later, followed by RecF. Thus, three repair proteins were differentially recruited to distinct sites on the nucleoids, potentially constituting active DSB repair centres (RCs). RecF did not form regular foci in the absence of RecN and failed to form any foci in recO cells, demonstrating a central role for RecN and RecO in initializing the formation of RCs. RecN/O/F foci were detected in recA, recG or recU mutant cells, indicating that the proteins act upstream of proteins involved in synapsis or post-synapsis. In the absence of exogenous DNA damage, RCs were rare, but they accumulated in recA and recU cells, suggesting that DSBs occur frequently in the absence of RecA or RecU. The results suggest a model in which RecN that forms multimers in solution and high-molecular-weight complexes in cells containing DSBs initiates the formation of RCs that mediate DSB repair with the homologous sister chromosome, which presents a novel concept for DSB repair in prokaryotes.