PROCESSING OF INTERMEDIATES IN RECOMBINATION AND DNA-REPAIR - IDENTIFICATION OF A NEW ENDONUCLEASE THAT SPECIFICALLY CLEAVES HOLLIDAY JUNCTIONS

被引:106
作者
SHARPLES, GJ [1 ]
CHAN, SN [1 ]
MAHDI, AA [1 ]
WHITBY, MC [1 ]
LLOYD, RG [1 ]
机构
[1] UNIV NOTTINGHAM HOSP,QUEENS MED CTR,DEPT GENET,NOTTINGHAM NG7 2UH,ENGLAND
关键词
ESCHERICHIA-COLI; HOLLIDAY JUNCTIONS; RESOLVASE; RUS PROTEIN;
D O I
10.1002/j.1460-2075.1994.tb06960.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
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 Bus 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 Bus suppresses the DNA repair and recombination defects of ruvA, ruvB and mvC mutants. We conclude that all ruv strains are defective injunction cleavage, and discuss pathways for Holliday junction resolution by RuvAB, RuvC, RecG and Rus.
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页码:6133 / 6142
页数:10
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