Pleiotropic control ofListeria monocytogenesvirulence factors by a gene that is autoregulated

摘要

SummaryEvidence for ptelotropic activation of virulence genes inListeria monocytogenesis presented. A complementation study of a spontaneousprfA‐deletion mutant and analysis of cassette and transposon insertion mutants showed that the geneprfAactivates the transcription of four independent genes which code for a phosphatidyl‐inositol‐specific phospholipase C (geneplcA), listeriolysin O (genehlyA), a metallo‐protease (geneprtA) and a lecithinase (geneprtC).Transcription ofprfAis not constitutive. During the growth phase, two peaks ofprfAtranscript accumulation were observed: the first was during exponential growth, and the second was at the beginning of the stationary phase. In addition, two prf4‐specific transcripts of 2.2 kb and 1 kb are detected. Early in exponential growth,prfAis co‐transcribed withplcAwhich lies upstreamprfA, giving rise to the 2.2 kbplcA‐prfAtranscript. In late‐exponential growth and at the beginning of the stationary phase,prfAtranscripts of 1 kb are predominantly detected. Our results demonstrate that sinceprfAcontrolsplcAtranscription, it also regulates it