EFFECT OF SINGLE BENZO[ALPHA]PYRENE DIOL EPOXIDE-DEOXYGUANOSINE ADDUCTS ON THE ACTION OF DNA-POLYMERASES IN-VITRO

Neither Sequenase 2.0 nor Klenow fragment were able to extend 12-mer p rimers using the eight templates (16-mers) derived by placing each of the four isomeric benzo[a]pyrene diol epoxide-deoxyguanosine adducts a t the 13th nucleotide from the 3'-end of two different sequence contex ts. Using an Il-mer primer to get a running start did not overcome the adduct induced block of primer extension except for the Klenow fragme nt and one of the two sequence contexts, indicating primer extension i s dependent on both the polymerase and sequence context. In this case, purine nucleoside triphosphates (dATP>dGTP) were incorporated opposit e each of the four adducts.