Open AccessImplication of hypR in the virulence and oxidative stress response of Enterococcus faecalis
Author(s) -
Verneuil Nicolas,
Rincé Alain,
Sanguinetti Maurizio,
Auffray Yanick,
Hartke Axel,
Giard JeanChristophe
Publication year - 2005
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/j.femsle.2005.08.043
Subject(s) - regulon , enterococcus faecalis , oxidative stress , virulence , microbiology and biotechnology , chemistry , biology , regulation of gene expression , gene , biochemistry , escherichia coli
HypR has recently been described as the first transcriptional regulator involved in the oxidative stress response and in the intracellular survival of Enterococcus faecalis within macrophages. In order to characterize the HypR regulon, real‐time quantitative RT‐PCR experiments were performed. The expression of four genes involved in the oxidative stress response encoding catalase, glutathione reductase, and the two subunits of alkyl hydroperoxide reductase were down regulated in the hypR background under H 2 O 2 condition. These findings show that HypR acts as a transcriptional activator, especially during oxidative stress. In addition, DNAse I footprinting assays allowed us to identify the HypR‐protected DNA regions corresponding to the “HypR box” in the hypR promoter. Moreover, the effect of the hypR mutation on the virulence of E. faecalis was evaluated in comparison with the wild‐type JH2–2 strain using a mouse peritonitis model. Our results revealed that HypR appears to be an important virulence factor in E. faecalis .