Mutagenesis by metal-induced oxygen radicals.
To assess the contribution of reactive oxygen species (ROS) to metal-induced mutagenesis, we have determined the spectrum of mutations in the lacZ alpha gene after exposure of M13mp2 DNA to Fe2+, Cu2+, and Ni2+. With iron and copper ions, mutations are clustered and are predominantly single-base substitutions. Fe, Cu, and phorbol ester-stimulated neutrophils also produced tandem double CC-->TT mutations. This mutation may provide a marker for the role of oxidative damage in carcinogenesis. Mutagenesis by Ni2+ required the complexing of the metal to a tripeptide and the addition of H2O2. To assess the contribution of ROS in mammalian cells, we determined the spectrum of mutations produced when purified DNA polymerases-alpha and -beta synthesized DNA using a template that had been damaged by ROS. The mutation spectra produced by the two polymerases indicates that these enzymes substitute different nucleotides opposite the same lesions.
Joseph Gottstein Memorial Cancer Research Laboratory, Department of Pathology, University of Washington School of Medicine, Seattle 98195.
T M
TM
Reid
D I
DI
Feig
L A
LA
Loeb
D001483:Base Sequence; D003300:Copper / Q000633:toxicity*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000633:toxicity*; D007938:Leukemia / Q000235:genetics; D008969:Molecular Sequence Data; D009153:Mutagens / Q000633:toxicity*; D009532:Nickel / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D009153:Mutagens; D017382:Reactive Oxygen Species; D003300:Copper; D009532:Nickel; D007501:Iron; D004259:DNA-Directed DNA Polymerase