title: Resolution of Holliday junctions in vitro requires the Escherichia coli ruvC gene product.
abstract: In previous studies, Holliday junctions generated during RecA-mediated strand-exchange reactions were resolved by fractionated Escherichia coli extracts. We now report the specific binding and cleavage of synthetic Holliday junctions (50 base pairs long) by a fraction purified by chromatography on DEAE-cellulose, phosphocellulose, and single-stranded DNA-cellulose. The cleavage reaction provided a sensitive assay with which to screen extracts prepared from recombination/repair-deficient mutants. Cells with mutations in ruvC lack the nuclease activity that cleaves synthetic Holliday junctions in vitro. This deficiency was restored by a multicopy plasmid carrying a ruvC+ gene that overexpressed junction-resolving activity. The UV sensitivity and deficiency in recombinational repair of DNA exhibited by ruv mutants lead us to suggest that RuvC resolves Holliday junctions in vivo.
authors.affiliation: Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Herts, United Kingdom.
authors.forename: B
authors.initials: B
authors.lastname: Connolly
authors.forename: C A
authors.initials: CA
authors.lastname: Parsons
authors.forename: F E
authors.initials: FE
authors.lastname: Benson
authors.forename: H J
authors.initials: HJ
authors.lastname: Dunderdale
authors.forename: G J
authors.initials: GJ
authors.lastname: Sharples
authors.forename: R G
authors.initials: RG
authors.lastname: Lloyd
authors.forename: S C
authors.initials: SC
authors.lastname: West
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D010584:Bacteriophage phi X 174 / Q000235:genetics; D001483:Base Sequence; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics*; D004279:DNA, Viral / Q000235:genetics; D004706:Endodeoxyribonucleases; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015870:Gene Expression; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D010957:Plasmids
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004279:DNA, Viral; D029968:Escherichia coli Proteins; D015345:Oligonucleotide Probes; C069806:ruvC protein, E coli; D004706:Endodeoxyribonucleases