Jensen Rasmus B
Department of Life Sciences and Chemistry, Roskilde University, Universitetsvej 1, DK-4000 Roskilde, Denmark.
J Bacteriol. 2006 Mar;188(6):2244-53. doi: 10.1128/JB.188.6.2244-2253.2006.
Progression through the Caulobacter crescentus cell cycle is coupled to a cellular differentiation program. The swarmer cell is replicationally quiescent, and DNA replication initiates at the swarmer-to-stalked cell transition. There is a very short delay between initiation of DNA replication and movement of one of the newly replicated origins to the opposite pole of the cell, indicating the absence of cohesion between the newly replicated origin-proximal parts of the Caulobacter chromosome. The terminus region of the chromosome becomes located at the invaginating septum in predivisional cells, and the completely replicated terminus regions stay associated with each other after chromosome replication is completed, disassociating very late in the cell cycle shortly before the final cell division event. Invagination of the cytoplasmic membrane occurs earlier than separation of the replicated terminus regions and formation of separate nucleoids, which results in trapping of a chromosome on either side of the cell division septum, indicating that there is not a nucleoid exclusion phenotype.
新月柄杆菌细胞周期的进程与细胞分化程序相关联。游动细胞处于复制静止状态，DNA复制在游动细胞向柄细胞转变时启动。DNA复制起始与其中一个新复制的起始点向细胞相对极移动之间存在非常短的延迟，这表明新月柄杆菌染色体新复制的起始点近端部分之间不存在黏连。染色体的末端区域位于分裂前细胞内陷的隔膜处，染色体复制完成后，完全复制的末端区域彼此保持关联，在细胞周期的后期，即在最终细胞分裂事件前不久才解离。细胞质膜的内陷早于复制的末端区域分离和单独类核的形成，这导致一条染色体被困在细胞分裂隔膜的两侧，表明不存在类核排斥表型。
