title: The global regulator H-NS binds to two distinct classes of sites within the Tn10 transpososome to promote transposition.
abstract: The histone-like nucleoid structuring protein (H-NS) is a global transcriptional regulator that influences stress response and virulence pathways in Gram-negative bacteria. H-NS also promotes Tn10 transposition by binding directly to the transpososome and inducing a conformational change in the transpososome that favours intermolecular transposition events. H-NS binds preferentially to curved DNA and can bend non-curved DNA, it self-oligomerizes and can interact with other proteins. To determine what functions of H-NS are important in promoting Tn10 transposition, we have examined the ability of two mutant forms of H-NS, P116S and 1-64, to act in Tn10 transposition. We provide evidence that the initial interaction of H-NS with the transpososome is dependent on H-NS binding to a specific structure in DNA flanking the transposon end. Additional molecules of H-NS then bind within the transposon end. This latter event appears to be directed by H-NS binding to the Tn10 transposase protein, and is important in maintaining the transpososome in a conformation that promotes intermolecular transposition. The binding of H-NS to a transposase protein is a novel function for this important regulatory molecule.
authors.affiliation: Department of Biochemistry, University of Western Ontario, London, Ontario, Canada N6A 5C1.
authors.forename: Chris M
authors.initials: CM
authors.lastname: Ward
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Wardle
authors.forename: Randeep K
authors.initials: RK
authors.lastname: Singh
authors.forename: David B
authors.initials: DB
authors.lastname: Haniford
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D018983:DNA Footprinting; D004251:DNA Transposable Elements / Q000502:physiology*; D004269:DNA, Bacterial / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D020125:Mutation, Missense; D011485:Protein Binding; D017384:Sequence Deletion; D019895:Transposases / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria; D019895:Transposases