The Werner syndrome protein stimulates DNA polymerase beta strand displacement synthesis via its helicase activity.
Werner syndrome is a hereditary premature aging disorder characterized by genomic instability. Genetic analysis and protein interaction studies indicate that the defective gene product (WRN) may play an important role in DNA replication, recombination, and repair. DNA polymerase beta (pol beta) is a central participant in both short and long-patch base excision repair (BER) pathways, which function to process most spontaneous, alkylated, and oxidative DNA damage. We report here a physical interaction between WRN and pol beta, and using purified proteins reconstitute of a portion of the long-patch BER pathway to examine a potential role for WRN in this repair response. We demonstrate that WRN stimulates pol beta strand displacement DNA synthesis and that this stimulation is dependent on the helicase activity of WRN. In addition, a truncated WRN protein, containing primarily the helicase domain, retains helicase activity and is sufficient to mediate the stimulation of pol beta. The WRN helicase also unwinds a BER substrate, providing evidence that WRN plays a role in unwinding DNA repair intermediates. Based on these findings, we propose a novel mechanism by which WRN may mediate pol beta-directed long-patch BER.
Harrigan
Jeanine A
JA
Laboratory of Molecular Gerontology, NIA, National Institutes of Health, Baltimore, Maryland 21224, USA.
Opresko
Patricia L
PL
von Kobbe
Cayetano
C
Kedar
Padmini S
PS
Prasad
Rajendra
R
Wilson
Samuel H
SH
Bohr
Vilhelm A
VA
D020137:Base Pair Mismatch / Q000235:genetics; D001483:Base Sequence; D004265:DNA Helicases / Q000378:metabolism*; D019951:DNA Polymerase beta / Q000378:metabolism*; D004260:DNA Repair / Q000235:genetics; D004261:DNA Replication / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay; D005090:Exodeoxyribonucleases; D006801:Humans; D009838:Oligodeoxyribonucleotides; D053484:RecQ Helicases; D011994:Recombinant Proteins / Q000378:metabolism; D011995:Recombination, Genetic; D013379:Substrate Specificity; D014898:Werner Syndrome / Q000201:enzymology* / Q000235:genetics*; D000071657:Werner Syndrome Helicase
D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D019951:DNA Polymerase beta; D005090:Exodeoxyribonucleases; D004265:DNA Helicases; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase