期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1991
卷号:88
期号:14
页码:6063-6067
DOI:10.1073/pnas.88.14.6063
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要: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.