title: The global bacterial regulator H-NS promotes transpososome formation and transposition in the Tn5 system.
abstract: The histone-like nucleoid structuring protein (H-NS) is an important regulator of stress response and virulence genes in gram-negative bacteria. In addition to binding regulatory regions of genes in a structure-specific manner, H-NS also binds in a structure-specific manner to sites in the Tn10 transpososome, allowing it to act as a positive regulator of Tn10 transposition. This is the only example to date of H-NS regulating a transposition system by interacting directly with the transposition machinery. In general, transposition complexes tend to include segments of deformed DNA and given the capacity of H-NS to bind such structures, and the results from the Tn10 system, we asked if H-NS might regulate another transposition system (Tn5) by directly binding the transposition machinery. We show in the current work that H-NS does bind Tn5 transposition complexes and use hydroxyl radical footprinting to characterize the H-NS interaction with the Tn5 transpososome. We also show that H-NS can promote Tn5 transpososome formation in vitro, which correlates with the Tn5 system showing a dependence on H-NS for transposition in vivo. Taken together the results suggest that H-NS might play an important role in the regulation of many different bacterial transposition systems and thereby contribute directly to lateral gene transfer.
authors.affiliation: Department of Biochemistry, University of Western Ontario, London, Ontario, Canada N6A 5C1.
authors.forename: Crystal R
authors.initials: CR
authors.lastname: Whitfield
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Wardle
authors.forename: David B
authors.initials: DB
authors.lastname: Haniford
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018983:DNA Footprinting; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria