The E. coli cell surface specifically prevents the initiation of DNA replication at oriC on hemimethylated DNA templates.
A particular outer membrane fraction previously defined as possessing specific affinity for the hemimethylated form of the origin of replication of the E. coli chromosome (oriC) is shown to inhibit the initiation of DNA synthesis at this site on hemimethylated DNA templates in vitro. The replication of fully methylated or unmethylated DNA templates is not affected. Also, no inhibition is observed if initiation takes place at random sites on the hemimethylated template. The key inactivation step appears to be membrane inhibition of DnaA initiator protein binding to oriC. Remethylation of the membrane-bound hemimethylated DNA results in reactivation. Our results demonstrate direct involvement of the membrane in the control of DNA replication. We propose that association/dissociation of the origin from the cell membrane is one of the control elements governing interinitiation times in E. coli.
Landoulsi
A
A
Institut Jacques Monod, Université Paris VII, France.
Malki
A
A
Kern
R
R
Kohiyama
M
M
Hughes
P
P
D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000502:physiology; D002876:Chromosomes, Bacterial; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics*; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D007700:Kinetics; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism; D010957:Plasmids; D012436:S-Adenosylmethionine / Q000378:metabolism; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); D013698:Templates, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; D029968:Escherichia coli Proteins; D012436:S-Adenosylmethionine; D008780:Methyltransferases; C058693:Dam methyltransferase; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); C499294:dam protein, E coli