Involvement of FtsZ in coupling of nucleoid separation with septation.
The cell-cycle parameters of an Escherichia coli strain expressing essential division gene ftsZ at one-fifth of its normal level, because of antisense regulation by DicF RNA, have been analysed. Inhibition of FtsZ expression affects neither the generation time nor the replication initiation mass, the C period, or the constriction period, but it does dramatically retard the initiation of constriction relative to replication termination. Separation of the nucleoids is equally postponed, indicating that division is not coupled to termination of replication, but to partitioning. The severe inhibition of nucleoid separation by DicF RNA, and its suppression by overproduction of FtsZ, suggest a role for FtsZ in the control of separation, and consequently in the coupling of separation and division. We suggest that the normal pattern of nucleoid separation previously found in cells deficient in ftsZ function was a consequence of the loss of a negative effect exerted by FtsZ on separation. In agreement with this view, we find that nucleoid separation is temporarily inhibited after arrest of FtsZ synthesis, but is later resumed as FtsZ is further diluted into the elongating filaments.
Tétart
F
F
Centre de Recherche de Biochimie et de Génétique Cellulaires du CNRS, Toulouse, France.
Albigot
R
R
Conter
A
A
Mulder
E
E
Bouché
J P
JP
D001426:Bacterial Proteins / Q000096:biosynthesis / Q000378:metabolism*; D002453:Cell Cycle / Q000235:genetics; D003598:Cytoskeletal Proteins; D004261:DNA Replication; D004926:Escherichia coli / Q000166:cytology* / Q000648:ultrastructure; D015964:Gene Expression Regulation, Bacterial
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria