Dynamics of Escherichia coli chromosome segregation during multifork replication
Dynamics of Escherichia coli chromosome segregation during multifork replication
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DOI：
10.1128/jb.01212-07
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发表时间：
2007-12-01
影响因子：
3.2
通讯作者：
Austin, Stuart
中科院分区：
文献类型：
--
作者：
Nielsen, Henrik J.;Youngren, Brenda;Austin, Stuart
缓慢生长的大肠杆菌细胞具有简单的细胞周期，在细胞分裂之前完成染色体的复制和进行性分离。在快速生长的细胞中，复制的起始发生在前一轮复制完成之前。在细胞分裂时，染色体包含多个复制叉，并且必须在这种复杂的复制模式仍在进行时被分离。在这里，我们表明，复制和隔离继续在步骤中，从起点和进展到复制末端。因此，多分支染色体上的早期复制标记在复制后不久继续分离以形成单独的原核，即使它们直到后代才被分离成不同的子细胞。分离模式遵循染色体复制模式，而不遵循细胞分裂周期。在任何生长速率下均未观察到姐妹DNA区域的广泛凝聚。我们的结论是隔离是由复制叉的进展。
Slowly growing Escherichia coli cells have a simple cell cycle, with replication and progressive segregation of the chromosome completed before cell division. In rapidly growing cells, initiation of replication occurs before the previous replication rounds are complete. At cell division, the chromosomes contain multiple replication forks and must be segregated while this complex pattern of replication is still ongoing. Here, we show that replication and segregation continue in step, starting at the origin and progressing to the replication terminus. Thus, early-replicated markers on the multiple-branched chromosomes continue to separate soon after replication to form separate protonucleoids, even though they are not segregated into different daughter cells until later generations. The segregation pattern follows the pattern of chromosome replication and does not follow the cell division cycle. No extensive cohesion of sister DNA regions was seen at any growth rate. We conclude that segregation is driven by the progression of the replication forks.