The nucleoid binding protein H-NS acts as an anti-channeling factor to favor intermolecular Tn10 transposition and dissemination.
Dissemination of the bacterial transposon Tn10 is limited by target site channeling, a process wherein the transposon ends are forced to interact with and insert into a target site located within the transposon. Integration host factor (IHF) promotes this self-destructive event by binding to the transpososome and forming a DNA loop close to one or both transposon ends; this loop imposes geometric and topological constraints that are responsible for channeling. We demonstrate that a second 'host' protein, histone-like nucleoid structuring protein (H-NS), acts as an anti-channeling factor to limit self-destructive intramolecular transposition events in vitro. Evidence that H-NS competes with IHF for binding to the Tn10 transpososome to block channeling and that this event is relatively insensitive to the level of DNA supercoiling present in the Tn10-containing substrate plasmid are presented. This latter observation is atypical for H-NS, as H-NS binding to other DNA sequences, such as promoters, is generally affected by subtle changes in DNA structure.
Singh
Randeep K
RK
Department of Biochemistry, University of Western Ontario, London, ON, Canada.
Liburd
Janine
J
Wardle
Simon J
SJ
Haniford
David B
DB
D001426:Bacterial Proteins / Q000378:metabolism*; D004251:DNA Transposable Elements / Q000235:genetics*; D004269:DNA, Bacterial / Q000737:chemistry; D004278:DNA, Superhelical / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D034982:Integration Host Factors / Q000378:metabolism; D050505:Mutant Proteins / Q000378:metabolism; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000737:chemistry; D011392:Proline / Q000235:genetics; D012694:Serine / Q000235:genetics
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria; D034982:Integration Host Factors; D050505:Mutant Proteins; D012694:Serine; D011392:Proline