Characterization of two signal transduction systems involved in intracellular macrophage survival and environmental stress response in Enterococcus faecalis.
The intracellular survival in mouse peritoneal macrophages of 8 Enterococcus faecalis response regulator mutants was tested to assess if the corresponding 2-component signal transduction systems (TCS) are involved in the ability of E. faecalis to survive in macrophages. Three mutants (err04, err05 and err06) are more susceptible than the wild-type JH2-2 strain and 1 is more resistant (err10). Then, characterization of the TCS Err04-Ehk04 and Err06-Ehk06 reveals that the first (homolog of PhoP-PhoR of Bacillus subtilis) is induced in phosphate deprivation conditions, regulates its own expression and plays a role in the expression of pstF encoding a phosphate-binding protein. The Err06-Ehk06 is involved in oxidative stress response. A mutation in the err06 gene increases sensitivity of the bacterium to H(2)O(2). The err06-ehk06 operon is induced by H(2)O(2) stress and controlled by 2 transcriptional start sites, of which 1 is specifically active in oxidative stress conditions. We also demonstrated that the expression of the catalase gene (kat) is partly dependant of the Err06-Ehk06 TCS.
Muller
Cécile
C
USC INRA 2017, Microbiologie de l'Environnement, EA 956, IRBA, Université de Caen, Caen, France.
Sanguinetti
Maurizio
M
Riboulet
Eliette
E
Hébert
Laurent
L
Posteraro
Brunella
B
Fadda
Giovanni
G
Auffray
Yanick
Y
Rincé
Alain
A
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D015169:Colony Count, Microbial; D013293:Enterococcus faecalis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D017737:Macrophages, Peritoneal / Q000382:microbiology*; D051379:Mice; D009154:Mutation; D018384:Oxidative Stress; D028044:Phosphate-Binding Proteins / Q000235:genetics / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D015398:Signal Transduction
D001426:Bacterial Proteins; D028044:Phosphate-Binding Proteins; D010710:Phosphates; D002374:Catalase