title: DNA polymerase δ-interacting protein 2 is a processivity factor for DNA polymerase λ during 8-oxo-7,8-dihydroguanine bypass.
abstract: The bypass of DNA lesions by the replication fork requires a switch between the replicative DNA polymerase (Pol) and a more specialized translesion synthesis (TLS) Pol to overcome the obstacle. DNA Pol δ-interacting protein 2 (PolDIP2) has been found to physically interact with Pol η, Pol ζ, and Rev1, suggesting a possible role of PolDIP2 in the TLS reaction. However, the consequences of PolDIP2 interaction on the properties of TLS Pols remain unknown. Here, we analyzed the effects of PolDIP2 on normal and TLS by five different human specialized Pols from three families: Pol δ (family B), Pol η and Pol ι (family Y), and Pol λ and Pol β (family X). Our results show that PolDIP2 also physically interacts with Pol λ, which is involved in the correct bypass of 8-oxo-7,8-dihydroguanine (8-oxo-G) lesions. This interaction increases both the processivity and catalytic efficiency of the error-free bypass of a 8-oxo-G lesion by both Pols η and λ, but not by Pols β or ι. Additionally, we provide evidence that PolDIP2 stimulates Pol δ without affecting its fidelity, facilitating the switch from Pol δ to Pol λ during 8-oxo-G TLS. PolDIP2 stimulates Pols λ and η mediated bypass of other common DNA lesions, such as abasic sites and cyclobutane thymine dimers. Finally, PolDIP2 silencing increases cell sensitivity to oxidative stress and its effect is further potentiated in a Pol λ deficient background, suggesting that PolDIP2 is an important mediator for TLS.
authors.affiliation: Institute of Molecular Genetics-Consiglio Nazionale delle Ricerche, I-27100 Pavia, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Maga
authors.forename: Emmanuele
authors.initials: E
authors.lastname: Crespan
authors.forename: Enni
authors.initials: E
authors.lastname: Markkanen
authors.forename: Ralph
authors.initials: R
authors.lastname: Imhof
authors.forename: Antonia
authors.initials: A
authors.lastname: Furrer
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Villani
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hübscher
authors.forename: Barbara
authors.initials: B
authors.lastname: van Loon
mesh_terms: D002852:Chromatography, Ion Exchange; D004249:DNA Damage / Q000235:genetics*; D019951:DNA Polymerase beta / Q000378:metabolism*; D004261:DNA Replication / Q000502:physiology*; D024202:Electrophoretic Mobility Shift Assay; D004926:Escherichia coli; D005453:Fluorescence; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D007700:Kinetics; D009687:Nuclear Proteins / Q000378:metabolism*; D009841:Oligonucleotides / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics
chemical_list: D009687:Nuclear Proteins; D009841:Oligonucleotides; C473592:POLDIP2 protein, human; D034741:RNA, Small Interfering; C024829:8-hydroxyguanine; D006147:Guanine; C415367:DNA polymerase beta2; D019951:DNA Polymerase beta
keywords: DNA repair; auxiliary factor; oxidative damage