Format

Send to

Choose Destination
Nucleic Acids Res. 2010 Aug;38(14):4722-30. doi: 10.1093/nar/gkq240. Epub 2010 Apr 12.

WRN helicase unwinds Okazaki fragment-like hybrids in a reaction stimulated by the human DHX9 helicase.

Author information

1
Leibniz Institute for Age Research (Fritz Lipmann Institute), Jena, Germany.

Abstract

Mutations in the Werner gene promote the segmental progeroid Werner syndrome (WS) with increased genomic instability and cancer. The Werner gene encodes a DNA helicase (WRN) that can engage in direct protein-protein interactions with DHX9, also known as RNA helicase A or nuclear DNA helicase II, which represents an essential enzyme involved in transcription and DNA repair. By using several synthetic nucleic acid substrates we demonstrate that WRN preferably unwinds RNA-containing Okazaki fragment-like substrates suggesting a role in lagging strand maturation of DNA replication. In contrast, DHX9 preferably unwinds RNA-RNA and RNA-DNA substrates, but fails to unwind Okazaki fragment-like hybrids. We further show that the preferential unwinding of RNA-containing substrates by WRN is stimulated by DHX9 in vitro, both on Okazaki fragment-like hybrids and on RNA-containing 'chicken-foot' structures. Collectively, our results suggest that WRN and DHX9 may also cooperate in vivo, e.g. at ongoing and stalled replication forks. In the latter case, the cooperation between both helicases may serve to form and to dissolve Holliday junction-like intermediates of regressed replication forks.

PMID:
20385589
PMCID:
PMC2919725
DOI:
10.1093/nar/gkq240
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center