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Processing of intermediates in recombination and DNA repair: identification of a new endonuclease that specifically cleaves Holliday junctions.

Sharples, G.J.; Chan, S.N.; Mahdi, A.A.; Whitby, M.C.; Lloyd, R.G.

Authors

S.N. Chan

A.A. Mahdi

M.C. Whitby

R.G. Lloyd



Abstract

The formation and subsequent resolution of Holliday junctions are critical stages in recombination. We describe a new Escherichia coli endonuclease that resolves Holliday intermediates by junction cleavage. The 14 kDa Rus protein binds DNA containing a synthetic four-way junction (X-DNA) and introduces symmetrical cuts in two strands to give nicked duplex products. Rus also processes Holliday intermediates made by RecA into products that are characteristic of junction resolution. The cleavage activity on X-DNA is remarkably similar to that of RuvC. Both proteins preferentially cut the same two strands at the same location. Increased expression of Rus suppresses the DNA repair and recombination defects of ruvA, ruvB and ruvC mutants. We conclude that all ruv strains are defective in junction cleavage, and discuss pathways for Holliday junction resolution by RuvAB, RuvC, RecG and Rus.

Citation

Sharples, G., Chan, S., Mahdi, A., Whitby, M., & Lloyd, R. (1994). Processing of intermediates in recombination and DNA repair: identification of a new endonuclease that specifically cleaves Holliday junctions. The EMBO Journal, 13(24), 6133-6142

Journal Article Type Article
Publication Date 1994
Journal EMBO Journal
Print ISSN 0261-4189
Publisher EMBO Press
Volume 13
Issue 24
Pages 6133-6142
Publisher URL http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=7813450