Error prone translesion synthesis past gamma-hydroxypropano deoxyguanosine, the primary acrolein-derived adduct in mammalian cells.
8-Hydroxy-5,6,7,8-tetrahydropyrimido[1,2-a]purin- 10(3H)-one,3-(2'-deoxyriboside) (1,N(2)-gamma-hydroxypropano deoxyguanosine, gamma-HOPdG) is a major DNA adduct that forms as a result of exposure to acrolein, an environmental pollutant and a product of endogenous lipid peroxidation. gamma-HOPdG has been shown previously not to be a miscoding lesion when replicated in Escherichia coli. In contrast to those prokaryotic studies, in vivo replication and mutagenesis assays in COS-7 cells using single stranded DNA containing a specific gamma-HOPdG adduct, revealed that the gamma-HOPdG adduct was significantly mutagenic. Analyses revealed both transversion and transition types of mutations at an overall mutagenic frequency of 7.4 x 10(-2)/translesion synthesis. In vitro gamma-HOPdG strongly blocks DNA synthesis by two major polymerases, pol delta and pol epsilon. Replicative blockage of pol delta by gamma-HOPdG could be diminished by the addition of proliferating cell nuclear antigen, leading to highly mutagenic translesion bypass across this adduct. The differential functioning and processing capacities of the mammalian polymerases may be responsible for the higher mutation frequencies observed in this study when compared with the accurate and efficient nonmutagenic bypass observed in the bacterial system.
Kanuri
Manorama
M
Sealy Center for Molecular Science, University of Texas Medical Branch, Galveston, Texas 77555, USA.
Minko
Irina G
IG
Nechev
Lubomir V
LV
Harris
Thomas M
TM
Harris
Constance M
CM
Lloyd
R Stephen
RS
D000171:Acrolein / Q000633:toxicity*; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D004247:DNA / Q000737:chemistry; D004249:DNA Damage; D004261:DNA Replication; D003849:Deoxyguanosine / Q000737:chemistry*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation
D000171:Acrolein; D004247:DNA; D003849:Deoxyguanosine