Unlinking chromosome catenanes in vivo by site-specific recombination
Unlinking chromosome catenanes in vivo by site-specific recombination
复制标题
DOI：
10.1038/sj.emboj.7601849
复制
发表时间：
2007-10-03
期刊：
影响因子：
11.4
通讯作者：
Sherratt, David J.
中科院分区：
文献类型：
--
作者：
Grainge, Ian;Bregu, Migena;Sherratt, David J.
在生命的所有领域中，染色体分离的一个挑战是形成连锁的子代染色体，这些子代染色体在复制过程中出现，是DNA双螺旋缠绕的结果。在DNA复制过程中和复制完成时，拓扑异构酶在DNA解链中起着关键作用。在这里，我们报告染色体解链可以通过多轮特定部位的重组来完成。我们证明了XerCD-dif或Cre-loxP的循序渐进的定点重组可以在体内解除细菌染色体的连接，在需要Kop引导的DNA转位的反应中通过FtsK。此外，我们还表明，当TopOIV的任一亚单位失活时，细胞质FtsK衍生物的过表达足以通过XerCD-dif重组使染色体解链。我们的结论是，FtsK在体内起到了简化染色体拓扑的作用，因为Xer重组相互转化了单体和二聚体染色体。
A challenge for chromosome segregation in all domains of life is the formation of catenated progeny chromosomes, which arise during replication as a consequence of the interwound strands of the DNA double helix. Topoisomerases play a key role in DNA unlinking both during and at the completion of replication. Here we report that chromosome unlinking can instead be accomplished by multiple rounds of site-specific recombination. We show that stepwise, site-specific recombination by XerCD-dif or Cre-loxP can unlink bacterial chromosomes in vivo, in reactions that require KOPS-guided DNA translocation by FtsK. Furthermore, we show that overexpression of a cytoplasmic FtsK derivative is sufficient to allow chromosome unlinking by XerCD-dif recombination when either subunit of TopoIV is inactivated. We conclude that FtsK acts in vivo to simplify chromosomal topology as Xer recombination interconverts monomeric and dimeric chromosomes.