Hale C A, de Boer P A
Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4960, USA.
J Bacteriol. 1999 Jan;181(1):167-76. doi: 10.1128/JB.181.1.167-176.1999.
Cell division in prokaryotes is mediated by the septal ring. In Escherichia coli, this organelle consists of several essential division proteins, including FtsZ, FtsA, and ZipA. To gain more insight into how the structure is assembled, we studied the interdependence of FtsZ, FtsA, and ZipA localization using both immunofluorescence and Gfp tagging techniques. To this end, we constructed a set of strains allowing us to determine the cellular location of each of these three proteins in cells from which one of the other two had been specifically depleted. Our results show that ZipA fails to accumulate in a ring shape in the absence of FtsZ. Conversely, depletion of ZipA does not abolish formation of FtsZ rings but leads to a significant reduction in the number of rings per unit of cell mass. In addition, ZipA does not appear to require FtsA for assembly into the septal ring and vice versa. It is suggested that septal ring formation starts by assembly of the FtsZ ring, after which ZipA and FtsA join this structure in a mutually independent fashion through direct interactions with the FtsZ protein.
原核生物中的细胞分裂由隔膜环介导。在大肠杆菌中，这个细胞器由几种必需的分裂蛋白组成，包括FtsZ、FtsA和ZipA。为了更深入地了解该结构是如何组装的，我们使用免疫荧光和绿色荧光蛋白（Gfp）标记技术研究了FtsZ、FtsA和ZipA定位之间的相互依赖性。为此，我们构建了一组菌株，使我们能够确定这三种蛋白质中每一种在另外两种中的一种已被特异性去除的细胞中的细胞定位。我们的结果表明，在没有FtsZ的情况下，ZipA无法以环状形式积累。相反，去除ZipA并不会消除FtsZ环的形成，但会导致每单位细胞质量中环的数量显著减少。此外，ZipA似乎不需要FtsA就能组装到隔膜环中，反之亦然。有人提出，隔膜环的形成始于FtsZ环的组装，之后ZipA和FtsA通过与FtsZ蛋白的直接相互作用以相互独立的方式加入该结构。
