Implication of hypR in the virulence and oxidative stress response of Enterococcus faecalis.
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.
Verneuil
Nicolas
N
Laboratoire de Microbiologie de l'Environnement, EA 956 soutenue par l'INRA, IRBA, Université de Caen, 14032 Caen Cedex, France.
Rincé
Alain
A
Sanguinetti
Maurizio
M
Auffray
Yanick
Y
Hartke
Axel
A
Giard
Jean-Christophe
JC
D000818:Animals; D021461:Animals, Outbred Strains; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D013293:Enterococcus faecalis / Q000472:pathogenicity* / Q000502:physiology; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology / Q000401:mortality; D018869:Heat-Shock Response; D051379:Mice; D008813:Mice, Inbred ICR; D018384:Oxidative Stress; D010538:Peritonitis / Q000382:microbiology / Q000401:mortality; D014158:Transcription, Genetic; D014774:Virulence
D001426:Bacterial Proteins