Co-ordinating DNA replication with cell division in bacteria: a link between the early stages of a round of replication and mid-cell Z ring assembly.
Spores of a thymine-requiring strain of Bacillus subtilis 168, which is also temperature sensitive for the initiation of chromosome replication, were germinated and allowed to grow out at the permissive temperature in a minimal medium containing no added thymine. Under these conditions, there was no or very limited progression into the elongation phase of the first round of replication. In a significant proportion of the outgrown cells, a Z ring formed precisely at mid-cell and over the centrally positioned nucleoid, leading eventually to the formation of a mature division septum. When initiation of the first round of replication was blocked through a temperature shift and with thymine present, the Z ring was positioned acentrally. The central Z ring that formed in the absence of thymine was blocked by the presence of a DNA polymerase III inhibitor. It is concluded that the very early stages of a round of replication (initiation plus possibly limited progression into the elongation phase) play a key role in the precise positioning of the Z ring at mid-cell and between replicating daughter chromosomes.
Department of Biochemistry, University of Sydney, NSW 2006, Australia.
E J
EJ
Harry
J
J
Rodwell
R G
RG
Wake
D001412:Bacillus subtilis / Q000166:cytology / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000502:physiology; D002455:Cell Division / Q000502:physiology*; D002876:Chromosomes, Bacterial / Q000502:physiology / Q000648:ultrastructure; D003598:Cytoskeletal Proteins; D004265:DNA Helicases / Q000502:physiology; D004261:DNA Replication / Q000502:physiology*; D004269:DNA, Bacterial / Q000096:biosynthesis*; D053488:DnaB Helicases; D013171:Spores, Bacterial; D013941:Thymine / Q000378:metabolism
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D004269:DNA, Bacterial; C071525:FtsZ protein, Bacteria; D004265:DNA Helicases; D053488:DnaB Helicases; D013941:Thymine