Abstract
Human DNA polymerase N (PolN) is an A-family nuclear DNA polymerase whose function is unknown. This study examines the possible role of PolN in DNA repair in human cells treated with PolN-targeted siRNA. HeLa cells with siRNA-mediated knockdown of PolN were more sensitive than control cells to DNA cross-linking agent mitomycin C (MMC) but were not hypersensitive to UV irradiation. The MMC hypersensitivity of PolN knockdown cells was rescued by the overexpression of DNA polymerase-proficient PolN but not by DNA polymerase-deficient PolN. Furthermore, in vitro experiments showed that purified PolN conducts low-efficiency nonmutagenic bypass of a psoralen DNA interstrand cross-link (ICL), whose structure resembles an intermediate in the proposed pathway of ICL repair. These results suggest that PolN might play a role in translesion DNA synthesis during ICL repair in human cells.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Base Sequence
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Cell Nucleus / drug effects
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Cell Nucleus / enzymology
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Cell Nucleus / genetics
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Cross-Linking Reagents / pharmacology
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DNA Damage* / genetics
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DNA Helicases / chemistry
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DNA Helicases / physiology
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DNA Repair Enzymes / chemistry
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DNA Repair Enzymes / physiology*
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DNA Repair* / drug effects
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DNA Repair* / genetics
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DNA-Binding Proteins / genetics
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DNA-Directed DNA Polymerase / biosynthesis
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DNA-Directed DNA Polymerase / chemistry
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DNA-Directed DNA Polymerase / deficiency
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DNA-Directed DNA Polymerase / genetics
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DNA-Directed DNA Polymerase / physiology*
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HeLa Cells
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Humans
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Mitomycin / pharmacology
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Molecular Sequence Data
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Nuclear Proteins / biosynthesis
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Nuclear Proteins / deficiency
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Nuclear Proteins / genetics
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Nuclear Proteins / physiology
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RNA, Small Interfering / pharmacology
Substances
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Cross-Linking Reagents
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DNA-Binding Proteins
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Nuclear Proteins
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RNA, Small Interfering
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xeroderma pigmentosum group F protein
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Mitomycin
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DNA-Directed DNA Polymerase
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POLN protein, human
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DNA Helicases
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DNA Repair Enzymes