Wu L J, Lewis P J, Allmansberger R, Hauser P M, Errington J
Sir William Dunn School of Pathology, University of Oxford, UK.
Genes Dev. 1995 Jun 1;9(11):1316-26. doi: 10.1101/gad.9.11.1316.
Spore formation in Bacillus subtilis begins with an asymmetric cell division that superficially resembles the division of vegetative cells. Mutations in the spoIIIE gene of B. subtilis partially block partitioning of one chromosome into the smaller (prespore) compartment of the sporulating cell. Point mutations that specifically block prespore chromosome partitioning affect a carboxy-terminal domain of SpoIIIE that shows significant sequence similarity to the DNA transfer (Tra) proteins of several conjugative plasmids of Streptomyces. In wild-type sporulating cells, the prespore chromosome passes through an intermediate stage resembling the state in which spoIIIE mutant cells are blocked. The prespore chromosome is then transferred progressively through the newly formed spore septum. We propose that translocation of the prespore chromosome occurs by a mechanism that is functionally related to the conjugative transfer of plasmid DNA.
枯草芽孢杆菌中的孢子形成始于不对称细胞分裂，这种分裂表面上类似于营养细胞的分裂。枯草芽孢杆菌spoIIIE基因的突变会部分阻止一条染色体分配到形成孢子的细胞的较小（前孢子）区室中。特异性阻止前孢子染色体分配的点突变会影响SpoIIIE的羧基末端结构域，该结构域与链霉菌几种接合质粒的DNA转移（Tra）蛋白具有显著的序列相似性。在野生型形成孢子的细胞中，前孢子染色体经历一个类似于spoIIIE突变细胞被阻断的状态的中间阶段。然后，前孢子染色体逐渐穿过新形成的孢子隔膜。我们提出，前孢子染色体的易位是通过一种在功能上与质粒DNA的接合转移相关的机制发生的。
