title: Unwinding the molecular basis of the Werner syndrome.
abstract: Werner syndrome (WS) is an autosomal recessive disease manifested by the premature onset of age-related phenotypes, including diseases such as atherosclerosis and cancer. This mimicry of normal aging with the possible exception of central nervous system manifestations has made it a focus of recent molecular studies on the pathophysiology of aging. In culture, cells obtained from patients with WS are genetically unstable, characterized by an increased frequency of nonclonal translocations and extensive DNA deletions. The WS gene product (WRN) is a DNA helicase belonging to the RecQ family, but is unique within this family in that it also contains an exonuclease activity. In addition to unwinding double-stranded DNA, WRN helicase is able to resolve aberrant DNA structures such as G4 tetraplexes, triplexes and 4-way junctions. Concordant with this structure-specificity, WRN exonuclease preferentially hydrolyzes alternative DNA that contains bubbles, extra-helical loops, 3-way junctions or 4-way junctions. WRN has been shown to bind to and/or functionally interact with other proteins, including replication protein A (RPA), proliferating cell nuclear antigen (PCNA), DNA topoisomerase I, Ku 86/70, DNA polymerase delta and p53. Each of these interacting proteins is involved in DNA transactions including those that resolve alternative DNA structures or repair DNA damage. The biochemical activities of WRN and the functions of WRN associated proteins suggest that in vivo WRN resolves DNA topological or structural aberrations that either occur during DNA metabolic processes such as recombination, replication and repair, or are the outcome of DNA damage.
authors.affiliation: Department of Pathology, University of Washington, Seattle, WA 98195-7705, USA. jcshen@u.washington.edu
authors.forename: J
authors.initials: J
authors.lastname: Shen
authors.forename: L A
authors.initials: LA
authors.lastname: Loeb
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004268:DNA-Binding Proteins; D005090:Exodeoxyribonucleases; D006801:Humans; D008954:Models, Biological; D053484:RecQ Helicases; D012441:Saccharomyces cerevisiae; D014898:Werner Syndrome / Q000201:enzymology* / Q000235:genetics; D000071657:Werner Syndrome Helicase
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D005090:Exodeoxyribonucleases; D000251:Adenosine Triphosphatases; C506725:RECQL protein, human; C430237:WRNIP1 protein, human; D000074183:ATPases Associated with Diverse Cellular Activities; D004265:DNA Helicases; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase