Skip to main content
. Author manuscript; available in PMC: 2009 Oct 2.
Published in final edited form as: Nat Rev Microbiol. 2006 Mar;4(3):183–192. doi: 10.1038/nrmicro1350
graphic file with name halms390766t1.jpg Methylated
Found at most GATC sites.
Signal for activation of dnaA gene transcription and for DnaA binding to oriC.
graphic file with name halms390766t2.jpg Hemimethylated (transient)
Found at all GATC sites after DNA replication.
Signal for Dam-dependent mismatch repair and for activation of cell cycle-coupled promoters (e.g., tnp IS10).
Signal for SeqA-mediated nucleiod organization.
Hemimethylated (extended)
Found at oriC upon sequestration by SeqA.
Prevents chromosome replication and dnaA gene transcription.
Signal for nucleiod segregation.
Hemimethylated (stable)
Created by binding of proteins that prevent Dam methylation in one or more DNA replication rounds.
An obligate step for switching in pap and agn43. Found also at specific sites on the chromosome.
graphic file with name halms390766t3.jpg Unmethylated
Created by binding of proteins that prevent methylation in two or more DNA replication rounds. At the pap regulatory region, created by Lrp. At the agn43 operator, created by OxyR. Found also at other chromosomal sites.