Chromosome and replisome dynamics in E. coli:: Loss of sister cohesion triggers global chromosome movement and mediates chromosome segregation
Chromosome and replisome dynamics in E. coli:: Loss of sister cohesion triggers global chromosome movement and mediates chromosome segregation
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DOI：
10.1016/j.cell.2005.04.013
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发表时间：
2005-06-17
期刊：
影响因子：
64.5
通讯作者：
Kleckner, N
中科院分区：
文献类型：
--
作者：
Bates, D;Kleckner, N
染色体和复制体动力学在同步大肠杆菌细胞进行真核样细胞周期检查。姐妹染色体在S期的大部分时间保持紧密的共定位，然后在一个单一的坐标转变中分离。作为功能独立的域，起始区和终止区表现不同。在分离过程中，姊妹基因座移动得很远，类核变成双叶状。起点和终点也会移动。我们推断姐妹最初是有联系的，凝聚力的丧失引发了全球染色体重组。这种重组产生了2重对称的、内外的构象，对E. coh来说，它包括姐妹分离。与真核生物前期的类比表明，这可能是一种原始的分离机制，后来添加了基于微管的过程。我们看不到长期存在的复制“工厂”；复制起始时间不随细胞质量而变化，我们确定了与细胞分裂密切相关的类核位置和状态的变化。我们认为细胞分裂通过这些变化许可了下一轮的复制起始。
Chromosome and replisome dynamics were examined in synchronized E. coli cells undergoing a eukaryotic-like cell cycle. Sister chromosomes remain tightly colocalized for much of S phase and then separate, in a single coordinate transition. Origin and terminus regions behave differently, as functionally independent domains. During separation, sister loci move far apart and the nucleoid becomes bilobed. Origins and terminus regions also move. We infer that sisters are initially linked and that loss of cohesion triggers global chromosome reorganization. This reorganization creates the 2-fold symmetric, ter-inlori-out conformation which, for E. coh, comprises sister segregation. Analogies with eukaryotic prometaphase suggest that this could be a primordial segregation mechanism to which microtubule-based processes were later added. We see no long-lived replication "factory"; replication initiation timing does not covary with cell mass, and we identify changes in nucleoid position and state that are tightly linked to cell division. We propose that cell division licenses the next round of replication initiation via these changes.