Bacterial DNA segregation by dynamic SopA polymers
Bacterial DNA segregation by dynamic SopA polymers
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DOI：
10.1073/pnas.0507222102
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发表时间：
2005-12-06
影响因子：
11.1
通讯作者：
Pogliano, J
中科院分区：
文献类型：
--
作者：
Lim, GE;Derman, AI;Pogliano, J
许多细菌质粒和染色体依赖于帕拉ATP酶在细胞内的正确定位和有效分离到子细胞。在这里，我们表明，F-质粒分配蛋白质SopA聚合成细丝在体外的ATP依赖性的方式，和细丝伸长的速度是类似的质粒分离在体内。我们发现，SopA是一个动态的蛋白质在细胞内，经历聚合和解聚的周期，并穿梭于核蛋白复合物之间，所述核蛋白复合物是由SopB蛋白结合到含有SopC的质粒（SopB/SopC）。SopA的动态行为对于Sop介导的质粒DNA分离至关重要;将SopA锁定到细胞中的静态聚合物中的突变抑制质粒分离。我们表明，SOPA与SOPB/SOPC在细胞中共定位，SOPB/SOPC成核SOPA的组装，并需要其动态行为。当SopA在含有SopB和sopC的DNA的存在下在体外聚合时，SopA丝从放射状星形花序中的质粒DNA发出。我们提出了一种机制，其中质粒分离是由聚合的SopA驱动，我们推测，径向组装的SopA聚合物是负责定位质粒之前和之后的隔离。
Many bacterial plasmids and chromosomes rely on ParA ATPases for proper positioning within the cell and for efficient segregation to daughter cells. Here we demonstrate that the F-plasmid-partitioning protein SopA polymerizes into filaments in an ATP-dependent manner in vitro, and that the filaments elongate at a rate that is similar to that of plasmid separation in vivo. We show that SopA is a dynamic protein within the cell, undergoing cycles of polymerization and depolymerization, and shuttling back and forth between nucleoprotein complexes that are composed of the SopB protein bound to sopC-containing plasmids (SopB/sopC). The dynamic behavior of SopA is critical for Sop-mediated plasmid DNA segregation; mutations that lock SopA into a static polymer in the cell inhibit plasmid segregation. We show that SopA colocalizes with SopB/sopC in the cell and that SopB/sopC nucleates the assembly of SopA and is required for its dynamic behavior. When SopA is polymerized in vitro in the presence of SopB and sopC-containing DNA, SopA filaments emanate from the plasmid DNA in radial asters. We propose a mechanism in which plasmid separation is driven by the polymerization of SopA, and we speculate that the radial assembly of SopA polymers is responsible for positioning plasmids both before and after segregation.