Format

Send to

Choose Destination
Infect Immun. 2008 Aug;76(8):3473-80. doi: 10.1128/IAI.00430-08. Epub 2008 Jun 16.

Identification of fevR, a novel regulator of virulence gene expression in Francisella novicida.

Author information

1
Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, USA.

Abstract

Francisella tularensis infects wild animals and humans to cause tularemia. This pathogen targets the cytosol of macrophages, where it replicates using the genes in the Francisella pathogenicity island (FPI). Virulence gene regulation in Francisella is complex, but transcriptional regulators MglA and SspA have been shown to regulate the expression of approximately 100 genes, including the entire FPI. We utilized a Francisella novicida transposon mutant library to identify additional regulatory factors and identified five additional genes that are essential for virulence gene expression. One regulatory gene, FTN_0480 (fevR, Francisella effector of virulence regulation), present in all Francisella species, is required for expression of the FPI genes and other genes in the MglA/SspA regulon. The expression of fevR is positively regulated by MglA. However, constitutive expression of fevR in an mglA mutant strain did not restore expression of the MglA/SspA regulon, demonstrating that mglA and fevR act in parallel to positively regulate virulence gene expression. Virulence studies revealed that fevR is essential for bacterial replication in macrophages and in mice, where we additionally show that fevR is required for the expression of genes in the MglA/SspA regulon in vivo. Thus, fevR is a crucial virulence gene in Francisella, required for the expression of virulence factors known to be essential for this pathogen's subversion of host defenses and pathogenesis in vivo.

PMID:
18559431
PMCID:
PMC2493208
DOI:
10.1128/IAI.00430-08
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center