title: A role for DNA polymerase θ in promoting replication through oxidative DNA lesion, thymine glycol, in human cells.
abstract: The biological functions of human DNA polymerase (pol) θ, an A family polymerase, have remained poorly defined. Here we identify a role of polθ in translesion synthesis (TLS) in human cells. We show that TLS through the thymine glycol (TG) lesion, the most common oxidation product of thymine, occurs via two alternative pathways, in one of which, polymerases κ and ζ function together and mediate error-free TLS, whereas in the other, polθ functions in an error-prone manner. Human polθ is comprised of an N-terminal ATPase/helicase domain, a large central domain, and a C-terminal polymerase domain; however, we find that only the C-terminal polymerase domain is required for TLS opposite TG in human cells. In contrast to TLS mediated by polκ and polζ, in which polζ would elongate the chain from the TG:A base pair formed by polκ action, the ability of polθ alone to carry out the nucleotide insertion step, as well as the subsequent extension step that presents a considerable impediment due to displacement of the 5' template base, suggests that the polθ active site can accommodate highly distorting DNA lesions.
authors.affiliation: From the Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, Texas 77555-1061.
authors.forename: Jung-Hoon
authors.initials: JH
authors.lastname: Yoon
authors.forename: Jayati
authors.initials: J
authors.lastname: Roy Choudhury
authors.forename: Jeseong
authors.initials: J
authors.lastname: Park
authors.forename: Satya
authors.initials: S
authors.lastname: Prakash
authors.forename: Louise
authors.initials: L
authors.lastname: Prakash
mesh_terms: D002460:Cell Line; D004261:DNA Replication / Q000502:physiology*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology*; D006801:Humans; D010084:Oxidation-Reduction; D017434:Protein Structure, Tertiary; D013941:Thymine / Q000031:analogs & derivatives* / Q000378:metabolism; D000097462:DNA Polymerase theta; D000099270:Y-Family DNA Polymerases
chemical_list: D004259:DNA-Directed DNA Polymerase; D013941:Thymine; D000097462:DNA Polymerase theta; C029389:thymine glycol; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases
keywords: DNA; DNA Damage; DNA Polymerase; DNA Polymerase θ; DNA Repair; DNA Replication; Lesion Bypass; Thymine Glycol