Mutagenesis of Escherichia coli: a method for determining mutagenic specificity by analysis of tRNA suppressors.
A method for estimating mutagenic specificity in Escherichia coli (argE3, hisG4, thr-1, supE44), based upon the isolation of Arg+ or His+ revertants and identification of tRNA suppressors, is described. The method gives an insight not only into mutagenic pathways but also into the functioning of tRNA. With N-methyl-N'-nitro-N-nitrosoguanidine, 98% of mutations are GC----AT transitions. With N4-hydroxycytidine, 100% are AT----GC transitions. With hydroxylamine, apart from GC----AT transitions, approximately 30% of Arg+ revertants are formed by GC (or AT)----TA transversions. When the chemistry of the mutagenic attack is known, the method allows us to discriminate whether mutations occur on the transcribed or non-transcribed strands of DNA. It has been found that reversion of argE3 to Arg+ is a better monitor of mutagenic pathways than reversion of hisG4 to His+.
Sledziewska-Gójska
E
E
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa.
Grzesiuk
E
E
Plachta
A
A
Janion
C
C
D001120:Arginine / Q000032:analysis; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics*; D006639:Histidine / Q000032:analysis; D016297:Mutagenesis, Site-Directed / Q000235:genetics*; D009153:Mutagens / Q000633:toxicity; D012329:RNA, Bacterial / Q000502:physiology*; D012343:RNA, Transfer / Q000502:physiology; D013489:Suppression, Genetic / Q000235:genetics*
D009153:Mutagens; D012329:RNA, Bacterial; D006639:Histidine; D012343:RNA, Transfer; D001120:Arginine