migS, a cis-acting site that affects bipolar positioning of oriC on the Escherichia coli chromosome
migS, a cis-acting site that affects bipolar positioning of oriC on the Escherichia coli chromosome
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DOI：
10.1038/sj.emboj.7600028
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发表时间：
2004-01-14
期刊：
影响因子：
11.4
通讯作者：
Niki, H
中科院分区：
文献类型：
--
作者：
Yamaichi, Y;Niki, H
在大肠杆菌染色体的复制过程中，复制的Ori结构域向相反的细胞两极迁移，这表明双极迁移的顺式作用位点位于该区域。为了鉴定该顺式作用位点，通过从原始染色体上分裂亚染色体构建了一系列突变体。一个突变体，含有一个720 kb的亚染色体，被发现是有缺陷的oriC的双极定位。缺失突变体的创建允许识别migS，一个25 bp的序列，作为oriC的双极定位的顺式作用位点。当migS位于复制末端时，染色体片段呈双极定位。migS能够拯救在SopABC分配系统中含有突变的质粒DNA的双极迁移。有趣的是，质粒上的migS序列的多个拷贝反式抑制oriC的双极定位。总之，这些发现表明，migS在oriC的双极定位中起着至关重要的作用。此外，在野生型和migS突变体的类核的动态形态变化的实时分析表明，双极定位的复制oriC有助于类核组织。
During replication of the Escherichia coli chromosome, the replicated Ori domains migrate towards opposite cell poles, suggesting that a cis-acting site for bipolar migration is located in this region. To identify this cis-acting site, a series of mutants was constructed by splitting subchromosomes from the original chromosome. One mutant, containing a 720 kb subchromosome, was found to be defective in the bipolar positioning of oriC. The creation of deletion mutants allowed the identification of migS, a 25 bp sequence, as the cis-acting site for the bipolar positioning of oriC. When migS was located at the replication terminus, the chromosomal segment showed bipolar positioning. migS was able to rescue bipolar migration of plasmid DNA containing a mutation in the SopABC partitioning system. Interestingly, multiple copies of the migS sequence on a plasmid in trans inhibited the bipolar positioning of oriC. Taken together, these findings indicate that migS plays a crucial role in the bipolar positioning of oriC. In addition, real-time analysis of the dynamic morphological changes of nucleoids in wild-type and migS mutants suggests that bipolar positioning of the replicated oriC contributes to nucleoid organization.