Regulation of plasmid virulence gene expression in Salmonella dublin involves an unusual operon structure

Characterization of three proteins expressed from the virulence region of plasmid pSDL2 in Salmonella dublin.

Infection of both cattle and humans with Salmonella dublin can result in septicemia and death. Like many nontyphoid Salmonella species that cause disease, S. dublin contains a cryptic plasmid (pSDL2) that is required for the full expression of virulence. Transposon mutagenesis of pSDL2 defined a 4.1-kb EcoRI region that is necessary for the development of a systemic infection in BALB/c mice. Th...

Tandem attenuators control expression of the Salmonella mgtCBR virulence operon

The mgtCBR operon from Salmonella enterica serovar Typhimurium specifies the virulence protein MgtC, the Mg(2+) transporter MgtB and the regulatory peptide MgtR. The mgtCBR transcript includes a long leader region harbouring two short open reading frames (ORFs). Translation of these ORFs is anticipated to impact the formation of particular stem-loop structures and control transcription of the ...

Characterization of translation termination mutations in the spv operon of the Salmonella virulence plasmid pSDL2.

The spv region of the Salmonella virulence plasmids consists of five genes located on an 8-kb fragment previously shown to be essential for virulence in mice. Four structural genes, spvABCD, form an operon that is transcriptionally activated by the spvR gene product in the stationary phase of growth. The role of the individual spv genes in the virulence phenotype was tested by isolating transla...

Regulation of virulence gene expression.

Physical and genetic mapping of the Salmonella dublin virulence plasmid pSDL2. Relationship to plasmids from other Salmonella strains.

Plasmids of approximately 80 kb in size are found in nearly all clinical isolates of Salmonella dublin and are believed to be essential for virulence. We have shown previously that the 80-kb plasmid pSDL2 is required for the S. dublin Lane strain to establish a lethal systemic infection in BALB/c mice after oral or intraperitoneal inoculation. We now present a physical and genetic characterizat...