The global regulator H-NS acts directly on the transpososome to promote Tn10 transposition.
The histone-like nucleoid structuring (H-NS) protein is a global transcriptional regulator that is known to regulate stress response pathways and virulence genes in bacteria. It has also been implicated in the regulation of bacterial transposition systems, including Tn10. We demonstrate here that H-NS promotes Tn10 transposition by binding directly to the transposition complex (or transpososome). We present evidence that, upon binding, H-NS induces the unfolding of the Tn10 transpososome and helps to maintain the transpososome in an unfolded state. This ensures that intermolecular (as opposed to self-destructive intramolecular) transposition events are favored. We present evidence that H-NS binding to the flanking donor DNA of the transpososome is the initiating event in the unfolding process. We propose that by recruiting H-NS as a modulator of transposition, Tn10 has evolved a means of sensing changes in host physiology, as the amount of H-NS in the cell, as well its activity, are responsive to changes in environmental conditions. Sensing of environmental changes through H-NS would allow transposition to occur when it is most opportune for both the transposon and the host.
Wardle
Simon J
SJ
Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1 Canada.
O'Carroll
Michelle
M
Derbyshire
Keith M
KM
Haniford
David B
DB
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020029:Base Pairing; D001483:Base Sequence; D001665:Binding Sites; D002122:Calcium Chloride / Q000494:pharmacology; D018983:DNA Footprinting; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D006493:Heparin / Q000494:pharmacology; D034982:Integration Host Factors / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008957:Models, Genetic; D009154:Mutation; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation / Q000187:drug effects; D011485:Protein Binding; D019895:Transposases / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C031908:H-NS protein, bacteria; D034982:Integration Host Factors; C473501:Tn10 transposase; D006493:Heparin; D019895:Transposases; D002122:Calcium Chloride