Correlation between transcription and C to T mutations in the non-transcribed DNA strand.
We recently showed that transcription can promote C to T mutations in the non-transcribed strand in E. coli. To study the relationship between the level of transcription and mutant frequency, an inactive allele of the kanamycin-resistance gene was expressed under the control of a hybrid promoter consisting of an UP element and the tac promoter. When this promoter is induced, the frequency of C to T mutations in the non-transcribed strand increases in rough proportion to the amount of mRNA. At the highest level of transcription at which cell growth is not affected, there is about a 10-fold increase in the frequency of mutations. This result is consistent with the hypothesis that transcription forces the non-transcribed strand to be in a single-stranded state and that this results in frequent C to T mutations.
Beletskii
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Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
Bhagwat
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AS
D002460:Cell Line; D003596:Cytosine; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics*; D009154:Mutation; D013941:Thymine; D014158:Transcription, Genetic
D004269:DNA, Bacterial; D003596:Cytosine; D013941:Thymine