Paper

Characterization of Two Signal Transduction Systems Involved in Intracellular Macrophage Survival and Environmental Stress Response in Enterococcus faecalis
Cécile Muller^a, Maurizio Sanguinetti^b, Eliette Riboulet^a, Laurent Hébert^a, Brunella Posteraro^b, Giovanni Fadda^b, Yanick Auffray^a, Alain Rincé<sup>a

a</sup>USC INRA 2017, Microbiologie de l'Environnement, EA 956, IRBA, Université de Caen, Caen, France;
^bInstitute of Microbiology, Catholic University of Sacred Heart, Rome, Italy

Address of Corresponding Author

J Mol Microbiol Biotechnol 2008;14:59-66 (DOI: 10.1159/000106083)

  Key Words

• Enterococcus faecalis
• 2-component signal transduction system
• Intracellular macrophage survival
• Phosphate starvation
• Oxidative stress

  Abstract

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 H₂O₂. The err06-ehk06 operon is induced by H₂O₂ 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.

Copyright © 2008 S. Karger AG, Basel

  Author Contacts

Alain Rincé
USC INRA 2017, Microbiologie de l'Environnement, EA 956, IRBA
Université de Caen
FR-14032 Caen Cedex (France)
Tel. +33 2 31 56 55 23, Fax +33 2 31 56 53 11, E-Mail alain.rince@unicaen.fr

  Article Information

Number of Print Pages : 8
Number of Figures : 4, Number of Tables : 1, Number of References : 31