title: A deletion within the murine Werner syndrome helicase induces sensitivity to inhibitors of topoisomerase and loss of cellular proliferative capacity.
abstract: Werner syndrome (WS) is an autosomal recessive disorder characterized by genomic instability and the premature onset of a number of age-related diseases. The gene responsible for WS encodes a member of the RecQ-like subfamily of DNA helicases. Here we show that its murine homologue maps to murine chromosome 8 in a region syntenic with the human WRN gene. We have deleted a segment of this gene and created Wrn-deficient embryonic stem (ES) cells and WS mice. While displaying reduced embryonic survival, live-born WS mice otherwise appear normal during their first year of life. Nonetheless, although several DNA repair systems are apparently intact in homozygous WS ES cells, such cells display a higher mutation rate and are significantly more sensitive to topoisomerase inhibitors (especially camptothecin) than are wild-type ES cells. Furthermore, mouse embryo fibroblasts derived from homozygous WS embryos show premature loss of proliferative capacity. At the molecular level, wild-type, but not mutant, WS protein copurifies through a series of centrifugation and chromatography steps with a multiprotein DNA replication complex.
authors.affiliation: Department of Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: M
authors.initials: M
authors.lastname: Lebel
authors.forename: P
authors.initials: P
authors.lastname: Leder
mesh_terms: D000818:Animals; D001483:Base Sequence; D002166:Camptothecin / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002678:Chimera; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D004265:DNA Helicases / Q000235:genetics*; D017931:DNA Primers; D005260:Female; D005313:Fetal Death; D006720:Homozygote; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D009115:Muridae; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011995:Recombination, Genetic; D017384:Sequence Deletion; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D014162:Transfection; D014898:Werner Syndrome / Q000201:enzymology / Q000235:genetics*
chemical_list: D017931:DNA Primers; D004265:DNA Helicases; D002166:Camptothecin