Hijacking of the Human Alkyl-N-purine-DNA Glycosylase by 3,N4-Ethenocytosine, a Lipid Peroxidation-induced DNA Adduct

• DOI: 10.1074/jbc.m314010200
• Publication Date: 2004-04-16T19:53:15Z
• Authors: Laurent Gros; Andrei V. Maksimenko; Cyril V. Privezen...; Jacques Laval; Murat K. Saparbaev
• Keywords: 0301 basic medicine; DNA Repair; Oligonucleotides; DNA, Single-Stranded; DNA; DNA Polymerase I; DNA Glycosylases; 3. Good health; Cytosine; DNA Adducts; Kinetics; Mice; 03 medical and health sciences; Escherichia coli; NIH 3T3 Cells; Animals; Humans; Protein Isoforms; Lipid Peroxidation; DNA Damage; DNA Primers; HeLa Cells; Mutagens

Lipid peroxidation generates aldehydes, which react with DNA bases, forming genotoxic exocyclic etheno(epsilon)-adducts. E-bases have been implicated in vinyl chloride-induced carcinogenesis, and increased levels of these lesions formed by endogenous processes are found human degenerative disorders. E-adducts repaired the base excision repair pathway. Here, we report efficient biological hijacking alkyl-N-purine-DNA glycosylase (ANPG) 3,N(4)-ethenocytosine (epsilonC) when present DNA. Unlike ethenopurines, ANPG does not excise, but binds to epsilonC either double-stranded or single-stranded We developed a direct assay, based on fluorescence quenching mechanism molecular beacons, measure activity. Molecular beacons containing modified residues used demonstrate that epsilonC.ANPG interaction inhibits both reconstituted systems cultured cells. Furthermore, show complex blocks primer extension Klenow fragment polymerase I. These results suggest could be more than 1,N(6)-ethenoadenine (epsilonA) vivo. The proposed model ANPG-mediated genotoxicity provides new insight basis lipid peroxidation-induced cell death genome instability cancer.