title: Transposition of Mu DNA: joining of Mu to target DNA can be uncoupled from cleavage at the ends of Mu.
abstract: Transposition of Mu involves transfer of the 3' ends of Mu DNA to the 5' ends of a staggered cut in the target DNA. We find that cleavage at the 3' ends of Mu DNA precedes cutting of the target DNA. The resulting nicked species exists as a noncovalent nucleoprotein complex in which the two Mu ends are held together. This cleaved donor complex completes strand transfer when a target DNA, Mu B protein, and ATP are provided. Mu end DNA sequences that have been precisely cut at their 3' ends by a restriction endonuclease, instead of by Mu A protein and HU, are efficiently transferred to a target DNA upon subsequent incubation with Mu A protein, Mu B protein, and ATP. Cleavage of the Mu ends therefore cannot be energetically coupled with joining these ends to a target DNA. We discuss the DNA strand transfer mechanism in view of these results, and propose a model involving direct transfer of the 5' ends of the cut target DNA, from their original partners, to the 3' ends of Mu.
authors.affiliation: National Institute of Diabetes, and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
authors.forename: R
authors.initials: R
authors.lastname: Craigie
authors.forename: K
authors.initials: K
authors.lastname: Mizuuchi
mesh_terms: D003090:Coliphages / Q000235:genetics*; D004251:DNA Transposable Elements; D004279:DNA, Viral / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D009698:Nucleoproteins / Q000378:metabolism; D010957:Plasmids
chemical_list: D004251:DNA Transposable Elements; D004279:DNA, Viral; D009698:Nucleoproteins