Beall B, Lutkenhaus J
Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City 66103.
Genes Dev. 1991 Mar;5(3):447-55. doi: 10.1101/gad.5.3.447.
A Bacillus subtilis strain was constructed in which the cell division gene, ftsZ, was placed under control of the isopropyl-beta-D-thiogalactoside (IPTG)-inducible spac promoter. This strain was dependent upon the presence of IPTG for cell division and colony formation indicating that ftsZ is an essential cell division gene in this organism. In sporulation medium this strain increased in mass and reached stationary phase in the presence or absence of IPTG, but only sporulated in the presence of IPTG. The expression of the sporulation genes spoIIG, spoIIA, and spoIIE occurred normally in the absence of IPTG as monitored by spo-lacZ fusions. However, expression of lacZ fusions to genes normally induced later in the developmental pathway, and that required processed pro-sigma E for expression, was inhibited. Immunoblot analysis revealed that pro-sigma E was not processed to its active form (sigma E) under these experimental conditions. Electron microscopy revealed that these FtsZ-depleted cells did not initiate asymmetric septation, suggesting that FtsZ has a common role in the initiation of both the vegetative and sporulation septa.
构建了一种枯草芽孢杆菌菌株，其中细胞分裂基因ftsZ置于异丙基-β-D-硫代半乳糖苷（IPTG）诱导型spac启动子的控制之下。该菌株的细胞分裂和菌落形成依赖于IPTG的存在，这表明ftsZ是该生物体中一个必需的细胞分裂基因。在芽孢形成培养基中，无论有无IPTG，该菌株的质量都会增加并达到稳定期，但只有在有IPTG的情况下才会形成芽孢。通过spo-lacZ融合监测发现，在没有IPTG的情况下，芽孢形成基因spoIIG、spoIIA和spoIIE的表达正常发生。然而，与通常在发育途径后期被诱导且其表达需要加工后的前体σE的基因的lacZ融合表达受到抑制。免疫印迹分析表明，在这些实验条件下，前体σE没有加工成其活性形式（σE）。电子显微镜显示，这些FtsZ缺失的细胞没有开始不对称隔膜形成，这表明FtsZ在营养细胞和芽孢形成隔膜的起始过程中具有共同作用。
