Segregation of the Escherichia coli chromosome terminus
Segregation of the Escherichia coli chromosome terminus
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DOI：
10.1046/j.1365-2958.2003.03746.x
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发表时间：
2003-11-01
影响因子：
3.6
通讯作者：
Austin, S
中科院分区：
文献类型：
--
作者：
Li, YF;Youngren, B;Austin, S
我们研究了分离的复制末端的大肠杆菌染色体的延时和静态显微镜。复制的末端一起位于细胞中心。它们在细胞分裂前迅速分离。在快速生长的情况下，复制体逐渐快速地向新生细胞的中心移动。在缓慢的生长速率下，末端通常保持在内细胞极附近，并在细胞周期的中间迁移到细胞中心。约160 kb的末端结构域，大致位于dif重组位点的中心，在细胞分裂时作为一个单位分离。在分裂前，这个结构域之外的序列分离，在分裂前细胞中产生两个独立的焦点。通过末端dif位点解析染色体二聚体需要XerC重组酶和FtsK蛋白的活性，该活性被认为可以在细胞中心对齐dif序列。我们发现，锚定的终端在细胞中心和适当的分离在细胞分裂正常发生在没有重组通过XerC重组酶。然而，当FtsK的C-末端结构域被截短时，克隆和适当的分离经常被破坏。
We studied the segregation of the replication terminus of the Escherichia coli chromosome by time-lapse and still photomicroscopy. The replicated termini lie together at the cell centre. They rapidly segregate away from each other immediately before cell division. At fast growth rate, the copies move progressively and quickly toward the centres of the new-born cells. At slow growth rate, the termini usually remain near the inner cell pole and migrate to the cell centre in the middle of the cell cycle. A terminus domain of about 160kb, roughly centred on the dif recombination site, segregated as a unit at cell division. Sequences outside this domain segregated before division, giving two separate foci in predivision cells. Resolution of chromosome dimers via the terminus dif site requires the XerC recombinase and an activity of the FtsK protein that is thought to align the dif sequences at the cell centre. We found that anchoring of the termini at the cell centre and proper segregation at cell division occurred normally in the absence of recombination via the XerC recombinase. Anchoring and proper segregation were, however, frequently disrupted when the C-terminal domain of FtsK was truncated.