Assembly of the SpoIIIE DNA translocase depends on chromosome trapping in Bacillus subtilis
Assembly of the SpoIIIE DNA translocase depends on chromosome trapping in Bacillus subtilis
复制标题
DOI：
10.1016/j.cub.2003.12.001
复制
发表时间：
2003-12-16
期刊：
影响因子：
9.2
通讯作者：
Losick, R
中科院分区：
文献类型：
--
作者：
Ben-Yehuda, S;Rudner, DZ;Losick, R
枯草芽孢杆菌的产孢是研究染色体跨膜易位的一个有吸引力的系统。产孢细胞含有两条姐妹染色体，它们凝聚在一根细长的轴向细丝中，复制起点锚定在孢子囊的两极[1，2]。随后在一极附近形成的隔膜将孢子囊不均等地分成前孢子（较小的隔室）和母细胞[3]。在花丝周围形成隔膜，将一条染色体的近端区域捕获在前孢子中。结果，被捕获的染色体穿过隔膜，其余的留在母细胞中[4]。接下来，SpoIIIE在隔膜的中间组装，产生一个移位酶，将起源远端的三分之二的染色体泵入前孢子[5]。在这里，我们解决的问题是如何组装的DNA移位酶，以及它如何定位到中隔中点。我们提出的证据表明，DNA横贯隔膜是一个锚，核形成的DNA移位酶。我们认为，DNA锚定是负责其他SpoIIIE样DNA易位酶的组装，如那些从进行二分裂的细胞分裂隔膜中去除被困染色体的易位酶。
Sporulation in Bacillus subtilis is an attractive system in which to study the translocation of a chromosome across a membrane. Sporulating cells contain two sister chromosomes that are condensed in an elongated axial filament with the origins of replication anchored at opposite poles of the sporangium [1, 2]. The subsequent formation of a septum near one pole divides the sporangium unequally into a forespore (the smaller compartment) and a mother cell [3]. The septum forms around the filament, trapping the origin-proximal region of one chromosome in the forespore. As a consequence, the trapped chromosome transverses the septum with the remainder being left in the mother cell [4]. Next, SpoIIIE assembles at the middle of the septum to create a translocase that pumps the origin-distal, two-thirds of the chromosome into the forespore [5]. Here, we address the question of how the DNA translocase assembles and how it localizes to the septal midpoint. We present evidence that DNA transversing the septum is an anchor that nucleates the formation of the DNA translocase. We propose that DNA anchoring is responsible for the assembly of other SpoIIIE-like DNA translocases, such as those that remove trapped chromosomes from the division septum of cells undergoing binary fission.