The role of MatP, ZapA and ZapB in chromosomal organization and dynamics in Escherichia coli.
The role of MatP, ZapA and ZapB in chromosomal organization and dynamics in Escherichia coli.
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DOI：
10.1093/nar/gkv1484
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发表时间：
2016-02-18
影响因子：
14.9
通讯作者：
Männik J
中科院分区：
文献类型：
--
作者：
Männik J;Castillo DE;Yang D;Siopsis G;Männik J
尽管进行了数十年的广泛研究，但关于大肠杆菌染色体如何在核内组织以及两个子染色体如何分离的全面观点尚未出现。在这里，我们研究了 MatP、ZapA 和 ZapB 蛋白在组织复制末端 (Ter) 区域和染色体分离过程中的作用。荧光标记的 Ter 区域的定量图像分析表明，复制末端以 MatP、ZapA 和 ZapB 依赖性方式沿细胞周边的单个片段附着在分裂体上。在缓慢生长条件下，该附着不会显着影响大量染色体分离。无论有或没有附着，两条染色体团以与细胞生长相当的速度彼此分离。分离甚至在复制末端区域将其自身定位到类核中心之前就开始了。基于构象熵的分离建模正确地预测了类核内复制末端区域的定位。然而，该模型产生的染色体密度分布与实验明显不同，表明构象熵在复制后期分离染色体方面发挥的作用有限。
Despite extensive research over several decades, a comprehensive view of how the Escherichia coli chromosome is organized within the nucleoid, and how two daughter chromosomes segregate has yet to emerge. Here we investigate the role of the MatP, ZapA and ZapB proteins in organizing the replication terminus (Ter) region and in the chromosomal segregation process. Quantitative image analysis of the fluorescently labeled Ter region shows that the replication terminus attaches to the divisome in a single segment along the perimeter of the cell in a MatP, ZapA and ZapB-dependent manner. The attachment does not significantly affect the bulk chromosome segregation in slow growth conditions. With or without the attachment, two chromosomal masses separate from each other at a speed comparable to the cell growth. The separation starts even before the replication terminus region positions itself at the center of the nucleoid. Modeling of the segregation based on conformational entropy correctly predicts the positioning of the replication terminus region within the nucleoid. However, the model produces a distinctly different chromosomal density distribution than the experiment, indicating that the conformational entropy plays a limited role in segregating the chromosomes in the late stages of replication.