The expression of virulence genes in Listeria monocytogenes is thermoregulated.

摘要: The expression of listeriolysin, a major virulence factor the gram-positive facultative intracellular pathogen Listeria monocytogenes, is positively regulated by transcriptional activator, prfA gene product. We had previously shown that mutations within lead to loss listeriolysin production. In this communication, regulation specific environmental condition, namely, temperature, was studied in wild-type strains monocytogenes. found hemolysis phenotype thermoregulated. A lisA::lacZ fusion constructed, and its strain at various growth temperatures. results showed beta-galactosidase activity expressed only when cultures were grown temperatures above 30 degrees C. This could be either specifically repressed or induced, depending on temperature. No change detected harboring control tested. Northern (RNA) blot analysis lisA-specific RNA transcripts thermoregulation manifested level transcription. also transcription other PrfA-regulated genes L. monocytogenes similarly affected Hence, as pathogens, Shigella Yersinia spp., temperature an important cue induction Our studies revealed higher imposed PrfA-mediated activation pathogenic