Preferential promutagenic lesions at exons 7–8 of human p53 genomic DNA induced by the direct-acting hepatocarcinogens N-nitroso-2-acetylaminofluorene and N-acetoxy-2-acetylaminofluorene

DNA polymerase fingerprint analysis (DPFA) was employed for identifying DNA-carcinogen adduct formation in the human p53 and lac gene sequence. Two ‘hot regions’ at codons 223–250 and 257–283 of the p53 gene were easily attacked by nitroso-2-acetylaminofluorene or acetoxy-2-acetylaminofluorene. However, the promutational lesions in lac gene were rather randomly distributed. The chemical treated plasmid (pUC 19) which contains lac gene were transfected into Escherichia coli JM109 cells and the induced lac gene mutants were selected with X-Gal plate as indicated by the appearance of white colonies. No mutational hot regions were found in the lac gene.