A cell cycle-regulated bacterial DNA methyltransferase is essential for viability.
The CcrM adenine DNA methyltransferase, which specifically modifies GANTC sequences, is necessary for viability in Caulobacter crescentus. To our knowledge, this is the first example of an essential prokaryotic DNA methyltransferase that is not part of a DNA restriction/modification system. Homologs of CcrM are widespread in the alpha subdivision of the Proteobacteria, suggesting that methylation at GANTC sites may have important functions in other members of this diverse group as well. Temporal control of DNA methylation state has an important role in Caulobacter development, and we show that this organism utilizes an unusual mechanism for control of remethylation of newly replicated DNA. CcrM is synthesized de novo late in the cell cycle, coincident with full methylation of the chromosome, and is then subjected to proteolysis prior to cell division.
Stephens
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Department of Development Biology, Beckman Center for Molecular and Genetic Medicine, Stanford University, CA 94305-5427, USA.
Reisenauer
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Wright
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Shapiro
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D000483:Alleles; D001419:Bacteria / Q000201:enzymology; D018407:Bacterial Physiological Phenomena; D001483:Base Sequence; D016934:Caulobacter / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D002453:Cell Cycle; D002876:Chromosomes, Bacterial; D017931:DNA Primers; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005838:Genotype; D007700:Kinetics; D008745:Methylation; D008969:Molecular Sequence Data; D010802:Phylogeny; D010957:Plasmids; D016133:Polymerase Chain Reaction; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000096:biosynthesis* / Q000235:genetics; D013045:Species Specificity; D013379:Substrate Specificity
D017931:DNA Primers; C098075:DNA modification methylase CcrM; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific)