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Review
. 1999 Sep;181(17):5135-9.
doi: 10.1128/JB.181.17.5135-5139.1999.

Bacterial DNA methylation: a cell cycle regulator?

A Reisenauer  1 , L S Kahng, S McCollum, L Shapiro
Affiliations
Review

Bacterial DNA methylation: a cell cycle regulator?

A Reisenauer et al. J Bacteriol. 1999 Sep.
No abstract available

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Figures

FIG. 1
FIG. 1
Domain organization of Dam and CcrM. (A) Diagram comparing the order of the conserved AdoMet-binding (green) and catalytic (yellow) domains in Dam and CcrM. As shown, the order of these domains is reversed in the α and β groups of methyltransferases. The putative target DNA recognition region is located between these domains. Conserved sequence motifs within the domains are indicated by Roman numerals (19). (B) Alignment of the C. crescentus (Cc), B. abortus (Ba), and R. meliloti (Rm) CcrM homologs. The three proteins are highly conserved (76 to 87% similarity). The green and yellow boxes highlight the proposed AdoMet-binding and catalytic domains, respectively. The asterisks below the sequence mark identical amino acids in all three proteins.
FIG. 2
FIG. 2
Changes in DNA methylation reflect the progression of chromosome replication during the Caulobacter cell cycle. (A) Diagram of the C. crescentus chromosome showing the locations of the origin of replication (Cori), the replication terminus, and three hypothetical methylation sites (labeled A, B, and C). (B) Methylation state of GANTC sites located at different distances from the origin at different stages in the cell cycle. Sites A, B, and C are fully methylated in the swarmer cell. After DNA replication initiates in the stalked cell, the time when each site becomes hemimethylated depends on its distance from Cori. The origin and surrounding sequences, such as site A, become hemimethylated earlier in the cell cycle and remain hemimethylated for a longer period of time compared to sites that are further from the origin (sites B and C). DNA near the replication terminus is hemimethylated very briefly. Just before cell division, a burst of CcrM methylation (shown by the yellow CcrM bar) restores the chromosome to the fully methylated state (32). The black oval and green theta structures within the cells represent quiescent and replicating chromosomes, respectively. (C) Diagram of fully methylated and hemimethylated DNA.
FIG. 3
FIG. 3
Control of CcrM methylation in Caulobacter. (A) Temporal and spatial control of CcrM and CtrA expression. The stage of the cell cycle when the CcrM DNA methyltransferase is present is indicated by the yellow CcrM bar beneath the cells. The presence of phosphorylated CtrA (CtrA∼P) during the cell cycle is shown in green. (B) Transcriptional regulation and constitutive proteolysis restrict CcrM expression to a narrow window of the cell cycle. CtrA∼P activates ccrM transcription by binding to its recognition sequence (black box) in the ccrM promoter. CcrM methylation of GANTC sites in the mRNA leader region (asterisks) represses transcription.
See this image and copyright information in PMC

References

    1. Bakker A, Smith D W. Methylation of GATC sites is required for precise timing between rounds of DNA replication in Escherichia coli. J Bacteriol. 1989;171:5738–5742. - PMC - PubMed
    1. Barbeyron T, Kean K, Forterre P. DNA adenine methylation of GATC sequences appeared recently in the Escherichia coli lineage. J Bacteriol. 1984;160:586–590. - PMC - PubMed
    1. Barras F, Marinus M G. The great GATC: DNA methylation in E. coli. Trends Genet. 1989;5:139–143. - PubMed
    1. Berdis A J, Lee I, Coward J K, Stephens C, Wright R, Shapiro L, Benkovic S J. A cell cycle-regulated adenine DNA methyltransferase from Caulobacter crescentus processively methylates GANTC sites on hemimethylated DNA. Proc Natl Acad Sci USA. 1998;95:2874–2879. - PMC - PubMed
    1. Boye E, Lobner-Olesen A. The role of dam methyltransferase in the control of DNA replication in E. coli. Cell. 1990;62:981–989. - PubMed

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