title: Analysis of the Xenopus Werner syndrome protein in DNA double-strand break repair.
abstract: Werner syndrome is associated with premature aging and increased risk of cancer. Werner syndrome protein (WRN) is a RecQ-type DNA helicase, which seems to participate in DNA replication, double-strand break (DSB) repair, and telomere maintenance; however, its exact function remains elusive. Using Xenopus egg extracts as the model system, we found that Xenopus WRN (xWRN) is recruited to discrete foci upon induction of DSBs. Depletion of xWRN has no significant effect on nonhomologous end-joining of DSB ends, but it causes a significant reduction in the homology-dependent single-strand annealing DSB repair pathway. These results provide the first direct biochemical evidence that links WRN to a specific DSB repair pathway. The assay for single-strand annealing that was developed in this study also provides a powerful biochemical system for mechanistic analysis of homology-dependent DSB repair.
authors.affiliation: Fox Chase Cancer Center, Philadelphia, PA 19111, USA. Hong_Yan@fccc.edu
authors.forename: Hong
authors.initials: H
authors.lastname: Yan
authors.forename: Jill
authors.initials: J
authors.lastname: McCane
authors.forename: Thomas
authors.initials: T
authors.lastname: Toczylowski
authors.forename: Chinyi
authors.initials: C
authors.lastname: Chen
mesh_terms: D000818:Animals; D002457:Cell Extracts / Q000737:chemistry; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism; D019457:Chromosome Breakage; D004249:DNA Damage; D004265:DNA Helicases / Q000737:chemistry / Q000378:metabolism*; D004260:DNA Repair; D004261:DNA Replication; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism; D010063:Ovum / Q000737:chemistry; D051135:Rad51 Recombinase / Q000378:metabolism; D011995:Recombination, Genetic / Q000502:physiology; D014898:Werner Syndrome / Q000378:metabolism*; D000071657:Werner Syndrome Helicase; D029867:Xenopus Proteins / Q000737:chemistry / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D002457:Cell Extracts; D002843:Chromatin; D004277:DNA, Single-Stranded; D029867:Xenopus Proteins; C495152:RAD51 protein, Xenopus; D051135:Rad51 Recombinase; D004265:DNA Helicases; D000071657:Werner Syndrome Helicase; C507159:WRN protein, Xenopus