title: Translesion synthesis across abasic lesions by human B-family and Y-family DNA polymerases α, δ, η, ι, κ, and REV1.
abstract: Abasic (apurinic/apyrimidinic, AP) sites are the most common DNA lesions formed in cells, induce severe blocks to DNA replication, and are highly mutagenic. Human Y-family translesion DNA polymerases (pols) such as pols η, ι, κ, and REV1 have been suggested to play roles in replicative bypass across many DNA lesions where B-family replicative pols stall, but their individual catalytic functions in AP site bypass are not well understood. In this study, oligonucleotides containing a synthetic abasic lesion (tetrahydrofuran analogue) were compared for catalytic efficiency and base selectivity with human Y-family pols η, ι, κ, and REV1 and B-family pols α and δ. Pol η and pol δ/proliferating cell nuclear antigen (PCNA) copied past AP sites quite effectively and generated products ranging from one-base to full-length extension. Pol ι and REV1 readily incorporated one base opposite AP sites but then stopped. Pols κ and α were severely blocked at AP sites. Pol η preferentially inserted T and A; pol ι inserted T, G, and A; pol κ inserted C and A; REV1 preferentially inserted C opposite AP sites. The B-family pols α and δ/PCNA preferentially inserted A (85% and 58%, respectively) consonant with the A-rule hypothesis. Pols η and δ/PCNA were much more efficient in next-base extension, preferably from A positioned opposite an AP site, than pol κ. These results suggest that AP sites might be bypassed with moderate efficiency by single B- and Y-family pols or combinations, possibly by REV1 and pols ι, η, and δ/PCNA at the insertion step opposite the lesion and by pols η and δ/PCNA at the subsequent extension step. The patterns of the base preferences of human B-family and Y-family pols in both insertion and extension are pertinent to some of the mutagenesis events induced by AP lesions in human cells.
authors.affiliation: Department of Pharmacology, School of Medicine, Ewha Womans University, 911-1, Mok-5-dong, Yangcheon-gu, Seoul 158-710, Republic of Korea. jychoi@ewha.ac.kr.
authors.forename: Jeong-Yun
authors.initials: JY
authors.lastname: Choi
authors.forename: Seonhee
authors.initials: S
authors.lastname: Lim
authors.forename: Eun-Jin
authors.initials: EJ
authors.lastname: Kim
authors.forename: Ara
authors.initials: A
authors.lastname: Jo
authors.forename: F Peter
authors.initials: FP
authors.lastname: Guengerich
mesh_terms: D004247:DNA / Q000378:metabolism; D004249:DNA Damage; D004256:DNA Polymerase I / Q000378:metabolism; D004258:DNA Polymerase III / Q000378:metabolism; D004260:DNA Repair; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D009687:Nuclear Proteins / Q000378:metabolism*; D009713:Nucleotidyltransferases / Q000378:metabolism*; D009841:Oligonucleotides / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D000094769:DNA Polymerase iota; D000099270:Y-Family DNA Polymerases
chemical_list: D004247:DNA; D004256:DNA Polymerase I; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase; D009687:Nuclear Proteins; D009713:Nucleotidyltransferases; D009841:Oligonucleotides; D018809:Proliferating Cell Nuclear Antigen; D000094769:DNA Polymerase iota; C429004:REV1 protein, human; D000099270:Y-Family DNA Polymerases; C404302:POLK protein, human; C112338:Rad30 protein; C000722070:POLI protein, human