Overview of controls in the Escherichia coli cell cycle.
The harmonious growth and cell-to-cell uniformity of steady-state bacterial populations indicate the existence of a well-regulated cell cycle, responding to a set of internal signals. In Escherichia coli, the key events of this cycle are the initiation of DNA replication, nucleoid segregation and the initiation of cell division. The replication initiator is the DnaA protein. In nucleoid segregation, the MukB protein, required for proper partitioning, may be a member of the myosin-kinesin superfamily of mechanoenzymes. In cell division, the FtsZ protein has a tubulin motif, is a GTPase and polymerizes in a ring around midcell during septation; the FtsA protein has an actin-like structure. The nature of the internal signals triggering these events is not known but candidates include cell mass, the superhelical density of the chromosome and the concentration of two regulatory nucleotides, cyclic AMP and ppGpp. The involvement of cytoskeletal-like proteins in key cycle events encourages the notion of a fundamental biological unity in cell cycle regulation in all organisms.
Vinella
D
D
Institut Jacques Monod, CNRS, Université Paris 7, France.
D'Ari
R
R
D001426:Bacterial Proteins / Q000378:metabolism; D002453:Cell Cycle; D002455:Cell Division; D002868:Chromosomal Proteins, Non-Histone; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics / Q000254:growth & development*; D029968:Escherichia coli Proteins; D020558:GTP Phosphohydrolases / Q000378:metabolism; D015870:Gene Expression; D006706:Homeostasis; D007700:Kinetics
D001426:Bacterial Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D029968:Escherichia coli Proteins; C067035:MukB protein, E coli; D020558:GTP Phosphohydrolases