title: Translesion DNA synthesis by human DNA polymerase eta on templates containing a pyrimidopurinone deoxyguanosine adduct, 3-(2'-deoxy-beta-d-erythro-pentofuranosyl)pyrimido-[1,2-a]purin-10(3H)-one.
abstract: M(1)dG (3-(2'-deoxy-beta-d-erythro-pentofuranosyl)pyrimido[1,2-a]purin-10(3H)-one) lesions are mutagenic in bacterial and mammalian cells, leading to base substitutions (mostly M(1)dG to dT and M(1)dG to dA) and frameshift mutations. M(1)dG is produced endogenously through the reaction of peroxidation products, base propenal or malondialdehyde, with deoxyguanosine residues in DNA. The mutagenicity of M(1)dG in Escherichia coli is dependent on the SOS response, specifically the umuC and umuD gene products, suggesting that mutagenic lesion bypass occurs by the action of translesion DNA polymerases, like DNA polymerase V. Bypass of DNA lesions by translesion DNA polymerases is conserved in bacteria, yeast, and mammalian cells. The ability of recombinant human DNA polymerase eta to synthesize DNA across from M(1)dG was studied. M(1)dG partially blocked DNA synthesis by polymerase eta. Using steady-state kinetics, we found that insertion of dCTP was the least favored insertion product opposite the M(1)dG lesion (800-fold less efficient than opposite dG). Extension from M(1)dG.dC was equally as efficient as from control primer-templates (dG.dC). dATP insertion opposite M(1)dG was the most favored insertion product (8-fold less efficient than opposite dG), but extension from M(1)dG.dA was 20-fold less efficient than dG.dC. The sequences of full-length human DNA polymerase eta bypass products of M(1)dG were determined by LC-ESI/MS/MS. Bypass products contained incorporation of dA (52%) or dC (16%) opposite M(1)dG or -1 frameshifts at the lesion site (31%). Human DNA polymerase eta bypass may lead to M(1)dG to dT and frameshift but likely not M(1)dG to dA mutations during DNA replication.
authors.affiliation: Department of Chemistry, A. B. Hancock, Jr., Memorial Laboratory for Cancer Research, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Stafford
authors.forename: Robert L
authors.initials: RL
authors.lastname: Eoff
authors.forename: Albena
authors.initials: A
authors.lastname: Kozekova
authors.forename: Carmelo J
authors.initials: CJ
authors.lastname: Rizzo
authors.forename: F Peter
authors.initials: FP
authors.lastname: Guengerich
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Marnett
mesh_terms: D017122:Bacteriophage T4 / Q000201:enzymology; D020137:Base Pair Mismatch; D001483:Base Sequence; D018736:DNA Adducts / Q000737:chemistry*; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D003849:Deoxyguanosine / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D006801:Humans; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011116:Polynucleotide 5'-Hydroxyl-Kinase / Q000378:metabolism; D011684:Purine Nucleosides; D011994:Recombinant Proteins / Q000378:metabolism; D013698:Templates, Genetic; D051981:Uracil-DNA Glycosidase / Q000378:metabolism; D000099270:Y-Family DNA Polymerases
chemical_list: D018736:DNA Adducts; D004259:DNA-Directed DNA Polymerase; D003849:Deoxyguanosine; D011116:Polynucleotide 5'-Hydroxyl-Kinase; D011684:Purine Nucleosides; D011994:Recombinant Proteins; D051981:Uracil-DNA Glycosidase; C491625:3-(2'-deoxy-beta-D-erythro-pentofuranosyl)pyrimido(1,2-alpha)purin-10(3H)-one; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases