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J Mol Microbiol Biotechnol. 2008;14(1-3):59-66.

Characterization of two signal transduction systems involved in intracellular macrophage survival and environmental stress response in Enterococcus faecalis.

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USC INRA 2017, Microbiologie de l'Environnement, EA 956, IRBA, Université de Caen, Caen, France.


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.

[Indexed for MEDLINE]

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