title: DNA polymerases κ and ζ cooperatively perform mutagenic translesion synthesis of the C8-2'-deoxyguanosine adduct of the dietary mutagen IQ in human cells.
abstract: The roles of translesion synthesis (TLS) DNA polymerases in bypassing the C8-2'-deoxyguanosine adduct (dG-C8-IQ) formed by 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), a highly mutagenic and carcinogenic heterocyclic amine found in cooked meats, were investigated. Three plasmid vectors containing the dG-C8-IQ adduct at the G1-, G2- or G3-positions of the NarI site (5'-G1G2CG3CC-3') were replicated in HEK293T cells. Fifty percent of the progeny from the G3 construct were mutants, largely G→T, compared to 18% and 24% from the G1 and G2 constructs, respectively. Mutation frequency (MF) of dG-C8-IQ was reduced by 38-67% upon siRNA knockdown of pol κ, whereas it was increased by 10-24% in pol η knockdown cells. When pol κ and pol ζ were simultaneously knocked down, MF of the G1 and G3 constructs was reduced from 18% and 50%, respectively, to <3%, whereas it was reduced from 24% to <1% in the G2 construct. In vitro TLS using yeast pol ζ showed that it can extend G3*:A pair more efficiently than G3*:C pair, but it is inefficient at nucleotide incorporation opposite dG-C8-IQ. We conclude that pol κ and pol ζ cooperatively carry out the majority of the error-prone TLS of dG-C8-IQ, whereas pol η is involved primarily in its error-free bypass.
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Arindam
authors.initials: A
authors.lastname: Bose
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Paritosh
authors.initials: P
authors.lastname: Pande
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Vijay P
authors.initials: VP
authors.lastname: Jasti
authors.affiliation: Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA.
authors.forename: Amy D
authors.initials: AD
authors.lastname: Millsap
authors.affiliation: Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA.
authors.forename: Edward K
authors.initials: EK
authors.lastname: Hawkins
authors.affiliation: Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA.
authors.forename: Carmelo J
authors.initials: CJ
authors.lastname: Rizzo
authors.affiliation: Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA ashis.basu@uconn.edu.
authors.forename: Ashis K
authors.initials: AK
authors.lastname: Basu
mesh_terms: D004247:DNA / Q000096:biosynthesis; D018736:DNA Adducts / Q000737:chemistry; D004259:DNA-Directed DNA Polymerase / Q000502:physiology*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000737:chemistry; D057809:HEK293 Cells; D006801:Humans; D009153:Mutagens / Q000737:chemistry; D059645:Mutation Rate; D011804:Quinolines / Q000737:chemistry; D000099270:Y-Family DNA Polymerases
chemical_list: D004247:DNA; D018736:DNA Adducts; D004259:DNA-Directed DNA Polymerase; D003849:Deoxyguanosine; D009153:Mutagens; D011804:Quinolines; C423422:C8-2'-deoxyguanosine-2-amino-3-methylimadazo(4,5-f)-quinoline adduct; C029216:2-amino-3-methylimidazo(4,5-f)quinoline; C425929:DNA polymerase zeta; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases; C112338:Rad30 protein