Disease relevance of dcm

• Nucleotide sequence of the dcm locus of Escherichia coli K12 [1].
• We found no phage restriction activity associated with the dcm clones [2].
• Absence in Bacillus subtilis and Staphylococcus aureus of the sequence-specific deoxyribonucleic acid methylation that is conferred in Escherichia coli K-12 by the dam and dcm enzymes [3].
• The sites that are methylated by the mec methylase in both plasmid and lambda phage DNAs were undermethylated in the dam overproducer as well [4].

High impact information on dcm

• Altered cytosine methylation frequency correlates with two previously described properties of "Arl-" phages, increased genetic recombination and unusual sensitivity of phage DNA to endonuclease S1, which are absent in phages grown on dcm or dcm arl bacteria [5].
• The repair is severely impaired in host strains carrying a mutation in any of the three loci dcm, mutL and mutS [6].
• The Escherichia coli chromosome contains specific, unmethylated dam and dcm sites [7].
• T:G and U:G mispairs in the methylatable sequence and in related sequences are recognized by the product of vsr, a gene adjacent to dcm [8].
• In Escherichia coli and related bacteria, the product of gene dcm methylates the second cytosine of 5'-CCWGG sequences (where W is A or T) [8].

Chemical compound and disease context of dcm

• The dcm locus of Escherichia coli K-12 has been shown to code for a methylase that methylates the second cytosine within the sequence 5'-CC(A/T)GG-3'. This sequence is also recognized by the EcoRII restriction-modification system coded by the E. coli plasmid N3 [2].
• VSP mismatch repair was greatly reduced in a dcm Escherichia coli mutant, in which 5-methylcytosine was not methylated [9].
• The product of the dcm gene is the only DNA cytosine-C5 methyltransferase of Escherichia coli K-12; it catalyses transfer of a methyl group from S-adenosyl methionine (SAM) to the C-5 position of the inner cytosine residue of the cognate sequence CCA/TGG [10].
• The gene encoding the vsr endonuclease is next to the gene specifying the E. coli dcm DNA-methyltransferase; an enzyme that adds CH3 groups to the first dC within its target sequence CC[A/T]GG, giving C5MeC[A/T]GG [11].
• We sequenced and characterized the hypervariable region of the methicillin resistance determinant (mec) isolated from Staphylococcus aureus BB270 [12].

Biological context of dcm

• Bacterial genes mutL, mutS, and dcm participate in repair of mismatches at 5-methylcytosine sites [9].
• We have investigated the susceptibility of the genomes of the related bacteriophages T3 and T7 to the three major DNA methyltransferases (EcoK, dam, dcm) of their host, Escherichia coli K12 [13].
• The gene essential for cytosine methylation, dcm, is predicted to code for a 473-amino-acid protein and is not required for VSP repair [14].
• The DNA cytosine methylase gene of Escherichia coli, dcm, overlaps an open reading frame (ORF) that continues in +1 register past the end of dcm [15].
• Mechanism of expression of DNA repair gene vsr, an Escherichia coli gene that overlaps the DNA cytosine methylase gene, dcm [15].

Associations of dcm with chemical compounds

• The methylase within the EcoRII system methylates the same cytosine as the dcm protein [2].
• However, mismatches in heteroduplexes prepared from lambda DNA lacking 5-methylcytosine were repaired in dcm+ bacteria [9].
• High levels of AdoMetase expression impaired AdoMet-mediated activities such as dam and dcm methylase-directed DNA modifications and the synthesis of spermidine from putrescine [16].
• In contrast, Tn3 was found to transpose more frequently in dcm+ (deoxycytosine methylase) cells than in dcm- mutants [17].
• Hybridization of this 3.5-kilobase Bg/II fragment with different methicillin-sensitive and methicillin-resistant S. aureus clinical isolates indicated that the fragment represents part of the methicillin resistance determinant (mec) [18].

Other interactions of dcm

• Based on these studies we conclude that there is a six-codon overlap between vsr and dcm [15].

Analytical, diagnostic and therapeutic context of dcm

• Northern blots were used to identify dcm-specific RNA species in wild type and dcm-6 cells [15].
• Additional DNA in methicillin-resistant Staphylococcus aureus and molecular cloning of mec-specific DNA [18].

References