Title: The roles of polymerases ν and θ in replicative bypass of O 6- and N 2-alkyl-2'-deoxyguanosine lesions in human cells.
Authors: Du, Hua; Wang, Pengcheng; Wu, Jun; He, Xiaomei; Wang, Yinsheng
Published In J Biol Chem, (2020 04 03)
Abstract: Exogenous and endogenous chemicals can react with DNA to produce DNA lesions that may block DNA replication. Not much is known about the roles of polymerase (Pol) ν and Pol θ in translesion synthesis (TLS) in cells. Here we examined the functions of these two polymerases in bypassing major-groove O 6-alkyl-2'-deoxyguanosine (O 6-alkyl-dG) and minor-groove N 2-alkyl-dG lesions in human cells, where the alkyl groups are ethyl, n-butyl (nBu), and, for O 6-alkyl-dG, pyridyloxobutyl. We found that Pol ν and Pol θ promote TLS across major-groove O 6-alkyl-dG lesions. O 6-alkyl-dG lesions mainly induced G→A mutations that were modulated by the two TLS polymerases and the structures of the alkyl groups. Simultaneous ablation of Pol ν and Pol θ resulted in diminished mutation frequencies for all three O 6-alkyl-dG lesions. Depletion of Pol ν alone reduced mutations only for O 6-nBu-dG, and sole loss of Pol θ attenuated the mutation rates for O 6-nBu-dG and O 6-pyridyloxobutyl-dG. Replication across the two N 2-alkyl-dG lesions was error-free, and Pol ν and Pol θ were dispensable for their replicative bypass. Together, our results provide critical knowledge about the involvement of Pol ν and Pol θ in bypassing alkylated guanine lesions in human cells.
PubMed ID: 32098870
MeSH Terms: Alkylation; Chromatography, High Pressure Liquid; DNA Repair; DNA-Directed DNA Polymerase/deficiency; DNA-Directed DNA Polymerase/genetics; DNA-Directed DNA Polymerase/metabolism*; Deoxyguanosine/analogs & derivatives*; Deoxyguanosine/analysis; Deoxyguanosine/metabolism; HEK293 Cells; Humans; Mutagenesis; Tandem Mass Spectrometry