title: Werner syndrome protein interacts functionally with translesion DNA polymerases.
abstract: Werner syndrome (WS) is characterized by premature onset of age-associated disorders and predisposition to cancer. The WS protein, WRN, encodes 3' --> 5' DNA helicase and 3' --> 5' DNA exonuclease activities, and is implicated in the maintenance of genomic stability. Translesion (TLS) DNA polymerases (Pols) insert nucleotides opposite replication-blocking DNA lesions and presumably prevent replication fork stalling/collapse. Here, we present in vitro and in vivo data that demonstrate functional interaction between WRN and the TLS Pols, Poleta, Polkappa, and Poliota. In vitro, WRN stimulates the extension activity of TLS Pols on lesion-free and lesion-containing DNA templates, and alleviates pausing at stalling lesions. Stimulation is mediated through an increase in the apparent V(max) of the polymerization reaction. Notably, by accelerating the rate of nucleotide incorporation, WRN increases mutagenesis by Poleta. In vivo, WRN and Poleta colocalize at replication-dependent foci in response to UVC irradiation. The functional interaction between WRN and TLS Pols may promote replication fork progression, at the expense of increased mutagenesis, and obviate the need to resolve stalled/collapsed forks by processes involving chromosomal rearrangements.
authors.affiliation: Department of Pathology, The Gottstein Memorial Cancer Research Center, University of Washington, Seattle, WA 98195, USA.
authors.forename: Ashwini S
authors.initials: AS
authors.lastname: Kamath-Loeb
authors.forename: Li
authors.initials: L
authors.lastname: Lan
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakajima
authors.forename: Akira
authors.initials: A
authors.lastname: Yasui
authors.forename: Lawrence A
authors.initials: LA
authors.lastname: Loeb
mesh_terms: D004247:DNA / Q000096:biosynthesis; D004249:DNA Damage; D004259:DNA-Directed DNA Polymerase / Q000145:classification / Q000378:metabolism*; D005090:Exodeoxyribonucleases; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007211:Indoles; D007700:Kinetics; D008856:Microscopy, Fluorescence; D016296:Mutagenesis; D053484:RecQ Helicases / Q000378:metabolism*; D013698:Templates, Genetic; D014466:Ultraviolet Rays; D000071657:Werner Syndrome Helicase
chemical_list: D005456:Fluorescent Dyes; D007211:Indoles; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; C007293:DAPI; D004247:DNA; D004259:DNA-Directed DNA Polymerase; D005090:Exodeoxyribonucleases; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase