Characterization of Ers, a PrfA-like regulator of Enterococcus faecalis.
We have identified a transcriptional regulator, named Ers (for enterococcal regulator of survival), of Enterococcus faecalis, an important opportunistic bacterium commonly recovered from hospitalized patients. Ers is a member of the Crp/Fnr family and is 69% similar to Srv, a PrfA-like regulator of Streptococcus pyogenes implicated in virulence, and is the E. faecalis protein most closely related to PrfA, a positive regulator of virulence genes in Listeria monocytogenes. In an in vivo-in vitro macrophage infection model, the survival of an ers mutant was highly significantly decreased compared with that of the parental strain JH2-2. This mutant was more than 10-fold more sensitive to oxidative challenge by hydrogen peroxide. In order to identify genes whose expression was under Ers control, the RNA levels of 31 likely candidates were measured by real-time quantitative PCR. The results indicate that ers may be autoregulated and that the locus ef0082 appears to be positively regulated by Ers. Nevertheless, mutation of ef0082 did not result in any detectable changes in the survival of the bacterium within murine macrophages.
Laboratoire de Microbiologie de l'Environnement, Université de Caen, France. jean-christophe.giard@unicaen.fr
Jean-Christophe
JC
Giard
Eliette
E
Riboulet
Nicolas
N
Verneuil
Maurizio
M
Sanguinetti
Yanick
Y
Auffray
Axel
A
Hartke
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D013293:Enterococcus faecalis / Q000235:genetics* / Q000276:immunology*; D005809:Genes, Regulator / Q000276:immunology*; D005816:Genetic Complementation Test; D016908:Gram-Positive Bacterial Infections / Q000276:immunology* / Q000382:microbiology; D017737:Macrophages, Peritoneal / Q000276:immunology / Q000382:microbiology; D051379:Mice; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D018384:Oxidative Stress / Q000276:immunology; D010454:Peptide Termination Factors / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment
D010454:Peptide Termination Factors; D012329:RNA, Bacterial