Mutagenic specificity in DNA base sequence by irradiation of health lamp light (UV-B) in Escherichia coli.
A shuttle vector, pZ189, carrying a bacterial suppressor tRNA marker gene, was irradiated with health lamp (HL) light containing UV-B. Plasmid mutations were scored by transforming an indicator strain of Escherichia coli carrying a suppressive blue amber mutation in the beta-galactosidase gene. Plasmid survival was also measured by transforming activity of the indicator strain. The majority of mutations induced by HL light were GC-AT transitions (69%) and the rest were transversions (31%). Some hot-spots in the mutations were observed by sequencing the suppressor gene. Mutagenic specificity in DNA base sequences induced by HL in E. coli agrees well with previous reports about 254-nm or 313-nm light effects on mammalian cells. This agreement may depend on the substitution of the inserted base instead of a G residue at the opposite site of a damaged C residue from conformational change of DNA structure in both bacterial and mammalian cells.
Okaichi
K
K
Department of Biology, Nara Medical University, Japan.
Nagashima
K
K
Nozu
K
K
Ohnishi
T
T
D000818:Animals; D001483:Base Sequence; D004269:DNA, Bacterial / Q000528:radiation effects; D004926:Escherichia coli / Q000235:genetics / Q000528:radiation effects*; D005822:Genetic Vectors; D006801:Humans; D008029:Lighting; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000528:radiation effects*; D010957:Plasmids; D014466:Ultraviolet Rays
D004269:DNA, Bacterial