Misincorporation of dAMP opposite 2-hydroxyadenine, an oxidative form of adenine.
Nucleotide incorporation opposite an oxidative form of adenine, 2-hydroxyadenine (2-OH-Ade) was investigated. When a primed template with 2-OH-Ade was treated with an exonuclease-deficient Klenow fragment of Escherichia coli DNA polymerase I (KFexo-), recombinant rat DNA polymerase beta (pol beta) or calf thymus DNA polymerase alpha (pol alpha), incorporation of dTMP and dAMP was observed. In addition, KFexo- inserted dGMP as well. A steady-state kinetic study indicated that the insertion of dAMP and dTMP opposite the DNA lesion occurred with similar frequency with KFexo- and pol beta. Insertion of dTMP opposite 2-OH-Ade was favored to that of dAMP by pol alpha. Chain extension from the A.2-OH-Ade pair is less favored than that from the T.2-OH-Ade pair by all three DNA polymerase. Analysis of full-length products of in vitro DNA synthesis showed that dTMP and dAMP were incorporated by DNA polymerases and that exonuclease-proficient and -deficient Klenow fragments also inserted dGMP opposite 2-OH-Ade. These results suggest that formation of 2-OH-Ade from A in DNA will induce A-->T and A-->C transversions in cells.
Kamiya
H
H
Department of Environmental Oncology, University of Occupational and Environmental Health, Kitakyushu, Japan.
Ueda
T
T
Ohgi
T
T
Matsukage
A
A
Kasai
H
H
D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D004247:DNA / Q000138:chemical synthesis; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry; D003838:Deoxyadenine Nucleotides / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D007700:Kinetics; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D051381:Rats
D003838:Deoxyadenine Nucleotides; D006147:Guanine; D004247:DNA; C008183:isoguanine; D004259:DNA-Directed DNA Polymerase