Translesional synthesis on DNA templates containing 8-oxo-7,8-dihydrodeoxyadenosine.
This study was designed to establish the miscoding potential of 8-oxo-7,8-dihydrodeoxyadenosine (8-oxo-dA). Oligodeoxynucleotides modified site-specifically with 8-oxo-dA were used as templates in primer extension reactions catalyzed by DNA polymerase I (Klenow fragment), DNA polymerase alpha (pol alpha), or DNA polymerase beta (pol beta). dTMP or dGMP is incorporated opposite 8-oxo-dA when either of these dNTPs is provided as substrate for DNA polymerase. dTMP is incorporated exclusively opposite 8-oxo-dA when all four dNTPs are present in the reaction mixture at equimolar concentrations. Chain extension is catalyzed efficiently by Klenow fragment and pol beta under conditions where 8-oxo-dA is paired with dT at the 3' terminus of the primed DNA template. Chain extension catalyzed by pol alpha proceeds more slowly. As shown by steady-state kinetic experiments, incorporation of dGMP is higher in reactions catalyzed by pol beta than by Klenow fragment or pol alpha. The dG-8-oxo-dA pair is extended efficiently from the 3' terminus in the absence of dTTP. We conclude that DNA containing 8-oxo-dA is capable of miscoding; however, unlike 8-oxo-dG, the mutagenic potential of this lesion is limited.
Shibutani
S
S
Department of Pharmacological Sciences, State University of New York, Stony Brook 11794-8651.
Bodepudi
V
V
Johnson
F
F
Grollman
A P
AP
D001483:Base Sequence; D004247:DNA / Q000096:biosynthesis*; D004249:DNA Damage; D004256:DNA Polymerase I / Q000378:metabolism; D004257:DNA Polymerase II / Q000378:metabolism; D003839:Deoxyadenosines / Q000737:chemistry*; D003848:Deoxyguanine Nucleotides / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016296:Mutagenesis; D009711:Nucleotides / Q000378:metabolism; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013698:Templates, Genetic; D013938:Thymidine Monophosphate / Q000378:metabolism
D003839:Deoxyadenosines; D003848:Deoxyguanine Nucleotides; D009711:Nucleotides; D009838:Oligodeoxyribonucleotides; D013938:Thymidine Monophosphate; C078251:2'-deoxy-7,8-dihydro-8-oxoadenosine; C007257:2'-deoxyguanosine 5'-phosphate; D004247:DNA; D004256:DNA Polymerase I; D004257:DNA Polymerase II