Effect of interaction between 5-azacytidine and DNA (cytosine-5) methyltransferase on C-to-G and C-to-T mutations in Escherichia coli.
The purpose of this study was to determine the effect of the Dcm cytosine methyltransferase on 5-azacytidine (5-azaC) mutagenesis in Escherichia coli. We used a Lac reversion assay to measure C-to-G and C-to-T mutations at a single, methylatable cytosine in the lacZ gene, in the presence and absence of Dcm. C-to-G mutations are stimulated by 5-azaC but are largely independent of Dcm. In contrast, C-to-T mutations are not stimulated by 5-azaC in either wild type or dcm cells. However, in cells which contain Dcm but are defective in very short patch repair, the normally high frequency of spontaneous C-to-T mutations is decreased by the analog in a dose-dependent manner.
Doiron
K M
KM
Biology Department, Concordia University, 1455 de Maisonneuve Blvd. W., Montréal, Québec, Canada.
Lavigne-Nicolas
J
J
Cupples
C G
CG
D001374:Azacitidine / Q000494:pharmacology*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D016296:Mutagenesis; D009152:Mutagenicity Tests; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D017354:Point Mutation / Q000187:drug effects
D004791:Enzyme Inhibitors; D004248:DNA (Cytosine-5-)-Methyltransferases; D001374:Azacitidine