Influence of flanking sequence context on the mutagenicity of acetylaminofluorene-derived DNA adducts in mammalian cells.
Site-specifically modified oligodeoxynucleotides were used to explore the influence of neighboring base sequence context on the mutagenic potential of N-(deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-AAF) and N-(deoxyguanosin-8-yl)-2-aminofluorene (dG-AF) in mammalian cells. Oligodeoxynucleotides ((5)(')TCCTCCTNXNCTCTC, where X is dG-AAF, dG-AF, or dG and N is C, A, G, or T) with different bases flanking the lesion were incorporated into a single-strand shuttle plasmid vector and used to establish the mutational frequency and specificity of dG-AAF and dG-AF adducts in simian kidney (COS-7) cells. Vectors containing dG-AAF promote preferential incorporation of dCMP at the site of the lesion; misincorporation of dAMP and dTMP also was observed. Mutational frequencies range from 11 to 23%. High mutational frequencies (18-23%) were observed when G or T was positioned 5' to dG-AAF and a lower frequency (11%) when C was 5' to the lesion. dCMP was predominantly incorporated opposite the dG-AF adduct when C, A, or T was 5' to the lesion; dAMP and dTMP were misincorporated at a frequency of 2-4%. With G 5' to the lesion, the overall mutational frequency for dG-AF ranged between 11 and 70%; the highest value occurred when C was the 3' flanking base, and the predominant mutation event was G --> T transversion (59%). We conclude from these experiments that dG-AAF and dG-AF promote G --> T transversions and G --> A transitions in mammalian cells. The mutational frequency and specificity of dG-AF vary significantly, depending on the nature of the bases flanking the lesion.
Shibutani
S
S
Laboratory of Chemical Biology, Department of Pharmacological Sciences, State University of New York at Stony Brook, 11794-8651, USA. shinya@pharm.sunysb.edu
Suzuki
N
N
Tan
X
X
Johnson
F
F
Grollman
A P
AP
D015073:2-Acetylaminofluorene / Q000031:analogs & derivatives* / Q000737:chemistry / Q000633:toxicity*; D020413:3' Untranslated Regions / Q000737:chemistry* / Q000235:genetics; D020121:5' Untranslated Regions / Q000737:chemistry* / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D019556:COS Cells / Q000187:drug effects / Q000378:metabolism*; D002522:Chlorocebus aethiops; D018736:DNA Adducts / Q000737:chemistry / Q000633:toxicity*; D004249:DNA Damage / Q000235:genetics; D004252:DNA Mutational Analysis; D015342:DNA Probes / Q000138:chemical synthesis; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000633:toxicity; D005822:Genetic Vectors / Q000138:chemical synthesis; D016297:Mutagenesis, Site-Directed; D009153:Mutagens / Q000737:chemistry / Q000633:toxicity*; D014162:Transfection
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D018736:DNA Adducts; D015342:DNA Probes; D009153:Mutagens; C018776:N-(deoxyguanosin-8-yl)acetylaminofluorene; D015073:2-Acetylaminofluorene; D003849:Deoxyguanosine