Regulation of hly expression in Listeria monocytogenes by carbon sources and pH occurs through separate mechanisms mediated by PrfA.

ABSTRACT: Expression of the PrfA-controlled virulence gene hly (encoding the pore-forming cytolysin listeriolysin) is under negative regulation by readily metabolized carbon sources in Listeria monocytogenes. However, the hyperhemolytic strain NCTC 7973 exhibits deregulated hly expression in the presence of repressing sugars, raising the possibility that a defect in carbon source regulation is responsible for its anomalous behavior. We show here that the activity of a second glucose-repressed enzyme, alpha-glucosidase, is 10-fold higher in NCTC 7973 than in 10403S. Using hly-gus fusions, we show that the prfA allele from NCTC 7973 causes deregulated hly-gus expression in the presence of sugars in either the wild-type or the NCTC 7973 background, while the 10403S prfA allele restores carbon source re

SUBMITTER: Behari J 

PROVIDER: S-EPMC108396 | biostudies-literature | 1998 Aug

REPOSITORIES: biostudies-literature