In vivo visualization of type II plasmid segregation: bacterial actin. laments pushing plasmids
In vivo visualization of type II plasmid segregation: bacterial actin. laments pushing plasmids
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DOI：
10.1083/jcb.200708206
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发表时间：
2007-12-03
影响因子：
7.8
通讯作者：
Mullins, R. Dyche
中科院分区：
文献类型：
--
作者：
Campbell, Christopher S.;Mullins, R. Dyche
II型par操纵子利用动态不稳定的肌动蛋白样蛋白ParM的聚合来分离杆状细菌中的低拷贝质粒。在这项研究中，我们使用延时摄影。用荧光显微镜观察大肠杆菌中的质粒动力学和ParM组装。缺乏par操纵子的质粒进行限制扩散，扩散常数为5 × 10 ~（-5）μ m（2）/ s，限制半径为0.28 μ m。含有单个PAR的质粒也扩散移动，但具有更大的扩散常数（4 × 10- 4 μ m（2）/ s）和限制半径（0.42 μ m）。ParM.质粒在体内是动态不稳定的，并形成连接成对的含PAR质粒的纺锤体，并将它们快速（3.1 μ m/ min）驱动到细胞的相反两极。到达两极后，Parm。迅速而彻底地哀悼。在ParM分解后，分离的质粒恢复扩散运动，经常彼此相遇多次并在单个细胞周期中经历多轮ParM依赖性分离。我们认为，除了驱动分离，par操纵子使质粒搜索空间和。更有效地找到姐妹质粒
Type II par operons harness polymerization of the dynamically unstable actin- like protein ParM to segregate low- copy plasmids in rod- shaped bacteria. In this study, we use time- lapse. fluorescence microscopy to follow plasmid dynamics and ParM assembly in Escherichia coli. Plasmids lacking a par operon undergo con. fined diffusion with a diffusion constant of 5 x 10(-5) mu m(2)/ s and a confinement radius of 0.28 mu m. Single par-containing plasmids also move diffusively but with a larger diffusion constant ( 4 x 10- 4 mu m(2)/ s) and confinement radius ( 0.42 mu m). ParM. laments are dynamically unstable in vivo and form spindles that link pairs of par- containing plasmids and drive them rapidly ( 3.1 mu m/ min) toward opposite poles of the cell. After reaching the poles, ParM. laments rapidly and completely depolymerize. After ParM disassembly, segregated plasmids resume diffusive motion, often encountering each other many times and undergoing multiple rounds of ParM- dependent segregation in a single cell cycle. We propose that in addition to driving segregation, the par operon enables plasmids to search space and. find sister plasmids more effectively.