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Sites of preferential induction of cyclobutane pyrimidine dimers in the nontranscribed strand of lacI correspond with sites of UV-induced mutation in Escherichia coli

Journal Article · · Journal of Biological Chemistry; (United States)
OSTI ID:5506415
; ;  [1]
  1. Department of Biology, York University, North York, Ontario (Canada)

An approach utilizing fluorescence-activated DNA sequencing technology was used to study the position and frequency of UV-induced lesions in the lacI gene of Escherichia coli. The spectrum of sites of UV damage in the NC+ region of the gene was compared with a published spectrum of UV-induced mutation in lacI . On average, the frequency of UV-induced lesions in the nontranscribed strand was higher than that in the transcribed strand in the region analyzed. A large fraction of mutations occurs at sites of UV-induced lesions in the nontranscribed strand, but not in the transcribed strand. This bias is reduced in an excision repair deficient (UvrB-) strain. In addition, mutations occur overwhelmingly at sites where a dipyrimidine sequence is present in the nontranscribed strand. This bias is also markedly reduced in the UvrB- strain. In light of recent work Mellon and Hanawalt describing the preferential removal of cyclobutane dimers from the transcribed strand of the expressed lacZ gene in E. coli, our data suggest that preferential strand repair may have a significant effect on mutagenesis.

OSTI ID:
5506415
Journal Information:
Journal of Biological Chemistry; (United States), Journal Name: Journal of Biological Chemistry; (United States) Vol. 266:18; ISSN JBCHA; ISSN 0021-9258
Country of Publication:
United States
Language:
English