title: Delayed transfection of DNA after riboflavin mediated photosensitization increases G:C to C:G transversions of supF gene in Escherichia coli mutY strain.
abstract: We have previously reported that the majority of base substitution mutations of the Escherichia coli supF gene induced by riboflavin mediated photosensitization were G:C to C:G changes, in addition to G:C to T:A changes which were probably caused by 8-hydroxyguanine (oh(8)Gua), in wild type and mutM mutator mutant strains. This implies that lesions other than oh(8)Gua are produced by riboflavin-photosensitization. G:C to C:G base substitutions have been found in the mutations induced by ionizing radiation and reactive oxygen species, as well as spontaneous mutation. To characterize the G:C to C:G mutation, riboflavin- photosensitized plasmid DNA carrying the supF gene was left at room temperature for 5 h in the dark before transfection. The delayed transfection gave a mutational spectrum different from that for immediate transfection. G:C to C:G transversions significantly increased in mutY mutator strain, in which the transversion was not detected in the immediate transfection. Lesions causing G:C to C:G changes increased during 5-h holding after photosensitization and MutY protein presumably takes part in this type of base change mutation.
authors.affiliation: Faculty of Agriculture, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Japan. takimoto@agr.yamaguchi-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Takimoto
authors.forename: K
authors.initials: K
authors.lastname: Tano
authors.forename: M
authors.initials: M
authors.lastname: Hashimoto
authors.forename: M
authors.initials: M
authors.lastname: Hori
authors.forename: S
authors.initials: S
authors.lastname: Akasaka
authors.forename: H
authors.initials: H
authors.lastname: Utsumi
mesh_terms: D001483:Base Sequence; D045647:DNA Glycosylases; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000187:drug effects / Q000528:radiation effects*; D004926:Escherichia coli / Q000235:genetics*; D016153:Genes, Suppressor; D008969:Molecular Sequence Data; D009154:Mutation; D009699:N-Glycosyl Hydrolases / Q000235:genetics*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D010957:Plasmids / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D017354:Point Mutation; D012343:RNA, Transfer / Q000235:genetics*; D012256:Riboflavin / Q000494:pharmacology*; D013997:Time Factors; D014169:Transformation, Bacterial
chemical_list: D004269:DNA, Bacterial; D017319:Photosensitizing Agents; C096275:supF tRNA; D012343:RNA, Transfer; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; C061738:mutY adenine glycosylase; D012256:Riboflavin