Evaluation of the mutagenic potential of the principal DNA adduct of acrolein

Acrolein is produced extensively in the environment by incomplete combustio n of organic materials, and it arises endogenously in humans as a metabolic by-product. Acrolein reacts with DNA at guanine residues to form the exocy clic adduct, 8-hydroxypropanodeoxyguanosine (HOPdG). Acrolein is mutagenic, and a correlation exists between HOPdG levels in Salmonella typhimurium tre ated with acrolein and a resultant increase in mutation frequency. Site-spe cifically modified oligonucleotides were used to explore the mutagenic pote ntial of HOPdG in Escherichia coli strains that mere either wild-type for r epair or deficient in nucleotide excision repair or base excision repair. O ligonucleotides modified with HOPdG were inserted into double-stranded bact eriophage vectors using the gapped-duplex method or into single-stranded ba cteriophage vectors and transformed into SOS-induced E. coli strains. Proge ny phage were analyzed by oligonucleotide hybridization to establish the mu tation frequency and the spectrum of mutations produced by HOPdG. The corre ct base, dCMP, was incorporated opposite HOPdG in all circumstances tested. In contrast, in vitro lesion bypass studies showed that HOPdG causes misin corporation opposite the modified base and is a block to replication. The c ombination of these studies showed that HOPdG is not miscoding in vivo at t he level of sensitivity of these site-specific mutagenesis assays.