title: Human DNA polymerase β, but not λ, can bypass a 2-deoxyribonolactone lesion together with proliferating cell nuclear antigen.
abstract: The C1'-oxidized lesion 2-deoxyribonolactone (L) is induced by free radical attack of DNA. This lesion is mutagenic, inhibits base excision repair, and can lead to strand scission. In double-stranded DNA L is repaired by long-patch base excision repair, but it induces replication fork arrest in a single-strand template. Translesion synthesis requires a specialized DNA polymerase (Pol). In E. coli, Pol V is responsible for bypassing L, whereas in yeast Pol ζ has been shown to be required for efficient bypass. Very little is known about the identity of human Pols capable of bypassing L. For instance, the activity of family X enzymes has never been investigated. We examined the ability of different family X Pols: Pols β, λ, and TdT from human cells and Pol IV from S. cerevisiae to act on DNA containing an isolated 2-deoxyribonolactone, as well as when the lesion comprises the 5'-component of a tandem lesion. We show that Pol β, but not Pol λ, can bypass a single L lesion in the template, and its activity is increased by the auxiliary protein proliferating cell nuclear antigen (PCNA), whereas both enzymes were completely blocked by a tandem lesion. Yeast Pol IV was able to bypass the single L and the tandem lesion but with little nucleotide insertion specificity. Finally, L did not affect the polymerization activity of the template-independent enzyme TdT.
authors.affiliation: Institute of Molecular Genetics IGM-CNR , via Abbiategrasso 207, I-27100 Pavia, Italy.
authors.forename: Emmanuele
authors.initials: E
authors.lastname: Crespan
authors.forename: Emanuela
authors.initials: E
authors.lastname: Pasi
authors.forename: Shuhei
authors.initials: S
authors.lastname: Imoto
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hübscher
authors.forename: Marc M
authors.initials: MM
authors.lastname: Greenberg
authors.forename: Giovanni
authors.initials: G
authors.lastname: Maga
mesh_terms: D019951:DNA Polymerase beta / Q000378:metabolism*; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D006801:Humans; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013400:Sugar Acids / Q000737:chemistry / Q000378:metabolism*
chemical_list: D018809:Proliferating Cell Nuclear Antigen; D011994:Recombinant Proteins; D013400:Sugar Acids; C056405:2,4,5-trihydroxypentanoic acid gamma-lactone; D019951:DNA Polymerase beta; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase