Affiliation:
1. Institut für Genetik und Mikrobiologie, Klinische Biochemie, Würzburg, Germany.
Abstract
The expression of listeriolysin, a major virulence factor of the gram-positive facultative intracellular pathogen Listeria monocytogenes, is positively regulated by a transcriptional activator, the prfA gene product. We had previously shown that mutations within the prfA gene lead to loss of listeriolysin production. In this communication, the regulation of expression of listeriolysin by a specific environmental condition, namely, temperature, was studied in wild-type strains of Listeria monocytogenes. We found that expression of the hemolysis phenotype was thermoregulated. A lisA::lacZ fusion was constructed, and its expression in the wild-type strain was studied at various growth temperatures. The results showed that the fusion beta-galactosidase activity was expressed only when cultures were grown at temperatures above 30 degrees C. This activity could be either specifically repressed or induced, depending on growth temperature. No change in activity was detected in a strain harboring a control beta-galactosidase fusion at the various growth temperatures tested. Northern (RNA) blot analysis of lisA-specific RNA transcripts showed that thermoregulation is manifested at the level of transcription. We also found that the transcription of other PrfA-regulated virulence genes in L. monocytogenes was similarly affected by growth temperature. Hence, as in other facultative intracellular pathogens, Shigella and Yersinia spp., temperature is an important cue in the induction of expression of virulence genes in L. monocytogenes. Our studies revealed that a higher level of regulation is imposed on the PrfA-mediated activation of virulence genes in pathogenic L. monocytogenes.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference38 articles.
1. Ausubel F. M. R. Brent R. E. Kingston D. D. Moore J. G. Seidman J. A. Smith and K. Struhl. 1989. Current protocols in molecular biology. John Wiley & Sons New York.
2. Chakraborty T. E. Domann and J. Wehland. Unpublished data.
3. Coordinate regulation of virulence genes in Listeria monocytogenes requires the product.of the prfA gene;Chakraborty T.;J. Bacteriol.,1991
4. Chakraborty T. M. Leimeister-Wfichter E. Domann and H. Hof. Unpublished data.
5. Molecular cloning, sequencing, and identification of a metalloprotease gene from Listeria monocytogenes that is species specific and physically linked to the listeriolysin gene;Domann E.;Infect. Immun.,1991
Cited by
217 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献