Mutational spectrum and recombinogenic effects induced by aminofluorene adducts in bacteriophage M13.
Double-stranded replicative form (RFI) DNA of bacteriophage M13 strain M13mp10 which carries partial lacZ gene has been modified in vitro to various extents with N-hydroxy-2-amino-fluorene (N-OH-AF) and then transfected into E. coli cells. High-performance liquid chromatography (HPLC) analysis results demonstrate that the sole adduct (95%) formed in modified DNA is N-(deoxyguanosine-8-yl)-2-aminofluorene (dG-C8-AF). Approximately 20 adducts per RFI molecule constitute 1 lethal event when plaque-forming ability is assayed on E. coli cells which have received no prior SOS induction. The mutagenicity of dG-C8-AF adducts was assayed by measuring loss of beta-galactosidase activity as a function of adducts per molecule. A dose-dependent increase in Lac- mutants was observed, with a 4-fold increase in mutants per survivor at 30 adducts/molecule. The mutations produced, characterized by DNA sequencing, occur predominantly at either G or C positions different from those observed in the spontaneous mutant spectrum. Restriction-mapping results show that in our assay system, dG-C8-AF adducts induce a previously unreported recombinogenic activity.
Ross
J
J
University of Texas System Cancer Center, Science Park-Research Division, Smithville 78957.
Doisy
R
R
Tang
M S
MS
D001435:Bacteriophages / Q000235:genetics*; D001483:Base Sequence; D002273:Carcinogens; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000494:pharmacology*; D018736:DNA Adducts; D004262:DNA Restriction Enzymes; D004279:DNA, Viral / Q000187:drug effects* / Q000235:genetics; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000494:pharmacology; D015252:Deoxyribonucleases, Type II Site-Specific; D005449:Fluorenes / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009153:Mutagens; D009154:Mutation; D011995:Recombination, Genetic / Q000187:drug effects*; D014162:Transfection
C052668:2-aminofluorene-DNA complex; D002273:Carcinogens; D018736:DNA Adducts; D004279:DNA, Viral; D005449:Fluorenes; D009153:Mutagens; C031838:N-(deoxyguanosin-8-yl)-2-aminofluorene; C001368:N-hydroxy-2-aminofluorene; D004247:DNA; D004262:DNA Restriction Enzymes; D015252:Deoxyribonucleases, Type II Site-Specific; C024403:GGCC-specific type II deoxyribonucleases; D003849:Deoxyguanosine