Cell-cycle-dependent spatial sequestration of the DnaA replication initiator protein in Bacillus subtilis.
Initiation of DNA replication must be restricted to occur only once per cell cycle. In most bacteria, DnaA protein binds replication origins and promotes the initiation of DNA replication. We have found that in Bacillus subtilis, DnaA only colocalizes with origin regions at early or late stages of the cell cycle, when the replication machinery is assembling or disassembling, respectively. In contrast, DnaA colocalizes with the DNA replication machinery during most of the cell cycle. Indeed, we present evidence that a primary function of YabA, a negative regulator of replication initiation, is to tether DnaA to the polymerase-clamp protein DnaN. Thus, YabA ensures that once the origin is duplicated, it moves away from the replisome and from DnaA. We propose that DnaA colocalization with origins is specific to the time of initiation, and that replisome/YabA-mediated spatial sequestration of DnaA prevents inappropriate reinitiation of DNA replication.
Soufo
Clarisse Defeu
CD
Faculty for Biology, Albert-Ludwigs-Universität Freiburg, University of Freiburg, Freiburg, Germany.
Soufo
Hervé Joël Defeu
HJ
Noirot-Gros
Marie-Françoise
MF
Steindorf
Astrid
A
Noirot
Philippe
P
Graumann
Peter L
PL
D001412:Bacillus subtilis / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002352:Carrier Proteins / Q000502:physiology*; D002453:Cell Cycle; D002499:Centrifugation, Density Gradient; D002876:Chromosomes, Bacterial / Q000378:metabolism; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D008970:Molecular Weight; D013395:Sucrose / Q000494:pharmacology; D013696:Temperature
D001426:Bacterial Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D013395:Sucrose