FtsK actively segregates sister chromosomes in Escherichia coli
FtsK actively segregates sister chromosomes in Escherichia coli
复制标题
FtsK 主动分离大肠杆菌中的姐妹染色体
DOI：
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发表时间：
2013
影响因子：
11.1
通讯作者：
F. Cornet
中科院分区：
文献类型：
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作者：
Mathieu Stouf;J. Meile;F. Cornet
细菌使用其环形染色体的复制起点到终点的极性来控制细胞周期中的DNA交易。分离始于起源区域的主动迁移，随后是其余染色体的渐进性移动。在二聚体姐妹染色体的情况下，以及当染色体组织因突变而受损时，分离的最后步骤已被广泛研究。在这些特殊情况下，需要分裂体相关的DNA转位酶FtsK。FtsK利用FtsK定向的极性序列(KOPS)DNA基序的极性将染色体泵向不同的染色体二聚体分辨位置。基于监测差异重组的分析表明，FtsK只在这些特殊情况下起作用，而不作用于单体染色体。使用双色系统对活细胞中的染色体基因座对进行可视化，我们发现姐妹基因座的空间分辨率从起始点到差异位置是准确排序的。此外，DIF周围200kb的∼区域的有序分离取决于FtsK的定向易位活性，而不取决于二聚体的形成或它们的分辨率。FtsK介导的分离需要MatP蛋白，MatP蛋白将不同周围区域的分离推迟到细胞分裂。我们得出结论，FtsK分离姐妹染色体的末端区域，无论它们是单体还是二聚体，并且以准确和有序的方式做到这一点。我们的数据与FtsK以面向KOPS的方式释放MatP介导的凝聚力和/或与终点区分裂装置的相互作用的模型一致。
Bacteria use the replication origin-to-terminus polarity of their circular chromosomes to control DNA transactions during the cell cycle. Segregation starts by active migration of the region of origin followed by progressive movement of the rest of the chromosomes. The last steps of segregation have been studied extensively in the case of dimeric sister chromosomes and when chromosome organization is impaired by mutations. In these special cases, the divisome-associated DNA translocase FtsK is required. FtsK pumps chromosomes toward the dif chromosome dimer resolution site using polarity of the FtsK-orienting polar sequence (KOPS) DNA motifs. Assays based on monitoring dif recombination have suggested that FtsK acts only in these special cases and does not act on monomeric chromosomes. Using a two-color system to visualize pairs of chromosome loci in living cells, we show that the spatial resolution of sister loci is accurately ordered from the point of origin to the dif site. Furthermore, ordered segregation in a region ∼200 kb long surrounding dif depended on the oriented translocation activity of FtsK but not on the formation of dimers or their resolution. FtsK-mediated segregation required the MatP protein, which delays segregation of the dif-surrounding region until cell division. We conclude that FtsK segregates the terminus region of sister chromosomes whether they are monomeric or dimeric and does so in an accurate and ordered manner. Our data are consistent with a model in which FtsK acts to release the MatP-mediated cohesion and/or interaction with the division apparatus of the terminus region in a KOPS-oriented manner.