An H-NS-like Stealth Protein Aids Horizontal DNA Transmission in Bacteria
Marie Doyle,1
Maria Fookes,2
Al Ivens,2
Michael W. Mangan,1
John Wain,2
Charles J. Dorman1*
The Sfh protein is encoded by self-transmissible plasmids involved in human typhoid and is closely related to the global regulator H-NS. We have found that Sfh provides a stealth function that allows the plasmids to be transmitted to new bacterial hosts with minimal effects on their fitness. Introducing the plasmid without the sfh gene imposes a mild H-NS– phenotype and a severe loss of fitness due to titration of the cellular pool of H-NS by the A+T-rich plasmid. This stealth strategy seems to be used widely to aid horizontal DNA transmission and has important implications for bacterial evolution.
1 Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland.
2 Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK.
* To whom correspondence should be addressed. E-mail: cjdorman{at}tcd.ie
