Bacterial cell division: themechanism and its precision

Abstract

The recent devlopment of cell biolofy technques for bacteria to allow visualisation of fundamental processes in time and space, and their use in synchronous populations of cells, has resulted in a dramatic increase in our understanding of cell division and it regulation in these tiny cells. The first stage of cell division is the formation of a Z ring, composed of apolymerised tubulin-like protein, FtZ,at the division site precisely at midcell. Several membrane-associated division proteins are then recruited to this ring to forma complex, the divisome, which causes invagination of the cell envelope layers to form a division septum. The z Ring marks the future division site, and the timing of assembly and positioning of this structure are important in determining where and when division will take place in the cell. Z ring assembly is controlled bnu many factors including negative regulatory mechanisms such as Min and nucleoid occlusion that influence Z ring positioning and FtZ accessory proteins that bind to FtZ directly and modulate its polymerisation behaviour. The replication status of the cell also influences the positionin of the Z ring,w hich may allow the tight coordination between DNA replication and cell division required toproduce two identical newborn cells.