H-NS is a part of a thermally controlled mechanism for bacterial gene regulation.
Temperature is a primary environmental stress to which micro-organisms must be able to adapt and respond rapidly. Whereas some bacteria are restricted to specific niches and have limited abilities to survive changes in their environment, others, such as members of the Enterobacteriaceae, can withstand wide fluctuations in temperature. In addition to regulating cellular physiology, pathogenic bacteria use temperature as a cue for activating virulence gene expression. This work confirms that the nucleoid-associated protein H-NS (histone-like nucleoid structuring protein) is an essential component in thermoregulation of Salmonella. On increasing the temperature from 25 to 37 degrees C, more than 200 genes from Salmonella enterica serovar Typhimurium showed H-NS-dependent up-regulation. The thermal activation of gene expression is extremely rapid and change in temperature affects the DNA-binding properties of H-NS. The reduction in gene repression brought about by the increase in temperature is concomitant with a conformational change in the protein, resulting in the decrease in size of high-order oligomers and the appearance of increasing concentrations of discrete dimers of H-NS. The present study addresses one of the key complex mechanisms by which H-NS regulates gene expression.
Ono
Shusuke
S
Department of Biochemistry and Molecular Biology, and Institute of Structural Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK.
Goldberg
Martin D
MD
Olsson
Tjelvar
T
Esposito
Diego
D
Hinton
Jay C D
JC
Ladbury
John E
JE
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006358:Hot Temperature; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011487:Protein Conformation; D012486:Salmonella typhimurium / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics; D015854:Up-Regulation
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria; C119659:HilC protein, Salmonella typhimurium; D014157:Transcription Factors