Role of the universal stress protein UspA of Salmonella in growth arrest, stress and virulence.
Pathogenic bacteria employ a variety of mechanisms to resist a barrage of stresses they encounter during active growth in or outside the host as well as during growth stasis. An in silico screen of the Salmonella genome sequence revealed that Salmonella typhimurium LT2 possesses a homologue belonging to the universal stress protein A (UspA) family. We assessed the transcriptional profile of uspA in S. typhimurium C5 by constructing a lacZ fusion revealing that uspA is induced by metabolic, oxidative, and temperature stresses. The highest transcriptional levels occurred in cells entering stationary phase, an observation consistent with expression patterns in Escherichia coli. The protein was purified as a fusion with GST (UspA(F)) and antibodies raised against UspA(F) revealed elevated protein levels in stressed and growth-arrested cells. Inactivation of uspA in S. typhimurium C5, lead to increased susceptibility to stress conditions. Furthermore, UspA makes an important contribution to the in vivo virulence of Salmonella in mice thus highlighting the importance of stress resistance regulation in pathogenicity and survival within the host.
Liu
Wen-Tssann
WT
Institute for Cell and Molecular Biosciences and School of Biomedical Sciences, The Medical School, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK.
Karavolos
Michail H
MH
Bulmer
David M
DM
Allaoui
Abdelmounaaïm
A
Hormaeche
Raquel Demarco Carlos E
RD
Lee
Jeong Jin
JJ
Khan
C M Anjam
CM
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018384:Oxidative Stress; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012480:Salmonella Infections / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology*; D013696:Temperature; D014158:Transcription, Genetic; D014774:Virulence
D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D011993:Recombinant Fusion Proteins; C078564:universal stress protein A, Bacteria