Cytosine DNA methylation influences drug resistance in Escherichia coli through increased sugE expression
Cytosine DNA methylation influences drug resistance in Escherichia coli through increased sugE expression
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DOI：
10.1111/1574-6968.12299
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发表时间：
2014-01-01
影响因子：
2.1
通讯作者：
Simon, Robert D.
中科院分区：
文献类型：
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作者：
Militello, Kevin T.;Mandarano, Alexandra H.;Simon, Robert D.
大肠埃希菌K-12菌株含有孤儿胞嘧啶-5 DNA甲基转移酶DCM(DNA胞嘧啶甲基转移酶)。最近的两篇报道表明，DCM对大肠杆菌中稳定期基因的表达有影响。在这里，我们证明了DCM基因敲除细胞过度表达耐药转运蛋白Suge，它与溴化乙锭(ETBR)耐药有关。在DNA甲基化抑制剂5-氮杂胞苷存在的情况下，Suge的表达也增加，这表明DCM介导的DNA甲基化通常抑制Suge的表达。DCM对Suge表达的影响主要局限于早期稳定期，而RPOS是Suge强健表达所必需的。DCM基因敲除的细胞比野生型细胞对ETBR的抗性更强，与质粒携带的DCM基因互补可恢复ETBR的敏感性。Suge基因敲除细胞比野生型细胞对ETBR更敏感。这些数据表明，DCM通过基因表达的改变影响对抗菌药物的敏感性。胞嘧啶DNA甲基转移酶DCM抑制药物转运体Suge的表达，而缺乏DCM基因的细胞过度表达Suge，对溴化乙锭的敏感性较低。
Escherichia coli K-12 strains contain the orphan cytosine-5 DNA methyltransferase enzyme Dcm (DNA cytosine methyltransferase). Two recent reports indicate that Dcm has an influence on stationary phase gene expression in E.coli. Herein, we demonstrate that dcm knockout cells overexpress the drug resistance transporter SugE, which has been linked to ethidium bromide (ETBR) resistance. SugE expression also increased in the presence of the DNA methylation inhibitor 5-azacytidine, suggesting that Dcm-mediated DNA methylation normally represses sugE expression. The effect of Dcm on sugE expression is primarily restricted to early stationary phase, and RpoS is required for robust sugE expression. Dcm knockout cells are more resistant to ETBR than wild-type cells, and complementation with a plasmid-borne dcm gene restores ETBR sensitivity. SugE knockout cells are more sensitive to ETBR than wild-type cells. These data indicate that Dcm influences the sensitivity to an antimicrobial compound through changes in gene expression.The cytosine DNA methyltransferase Dcm represses the expression of the drug transporter SugE, and cells lacking the dcm gene overexpress SugE and are less sensitive to ethidium bromide.