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Cytosine DNA Methylation Influences Drug Sensitivity through SugE Expression in Escherichia coli
Author(s) -
Mandarano Alexandra H,
Varechtchouk Olga,
Simon Robert D,
Militello Kevin T
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.837.1
Subject(s) - dna methylation , microbiology and biotechnology , methylation , escherichia coli , ethidium bromide , cytosine , gene , biology , dna , gene knockout , gene expression , chemistry , biochemistry
In Escherichia coli , the second cytosine in the sequence 5′CC(A/T)GG3′ is methylated by the Dcm enzyme. Our laboratory has previously shown that DNA methylation represses expression of ribosomal proteins. The laboratory is currently investigating other targets of Dcm‐mediated DNA methylation. The sugE gene has been shown to confer resistance to quaternary ammonium compounds, and the sugE gene has one dcm recognition site in its 5′ flanking region, three in the open reading frame and one in the 3′ flanking region. We used qPCR to measure sugE RNA levels at both log and stationary phases in wild‐type and dcm knockout cells. Our data demonstrate that the sugE gene is overexpressed at both phases in dcm knockout cells. SugE expression also increased in the presence of 5‐azacytidine, an inhibitor of cytosine DNA methylation. In order to determine if dcm influences sensitivity to different antibacterial compounds, the sensitivity to ethidium bromide (EtBr) in wild‐type, dcm knockout, and sugE knockout strains was compared using Kirby‐Bauer disc diffusions assays, MIC assays and growth curve analysis. Our data indicate that sugE knockout cells are hypersensitive to EtBr, whereas dcm knockout cells have increased resistance to EtBr. We are currently testing a panel of quaternary ammonium compounds in these assays. In summary, DNA methylation can influence the sensitivity to antibacterial compounds.