Quorum sensing dependent repression of the Staphylococcus aureus transcription termination factor Rho is necessary for pathogenicity

Abstract

In Staphylococcus aureus, the transcription termination Rho factor has been identified as an attenuator of virulence, highlighting this universal protein as a new player in S. aureus pathophysiology. Moreover, Rho is required for the repression of "pervasive" transcription, which results from transcription at cryptic promoters or from transcriptional readthrough. In our study, we demonstrated that the rho transcript is specifically repressed by the quorum sensing-dependent RNAIII during the stationary phase of growth, allowing exotoxins to be activated at this stage. Rho-dependent RNA targets were identified using RIP-seq and differential transcriptomic analyses, revealing that several of these targets are involved in adhesion, dissemination, and the host responses. Our data provide a molecular explanation for the functions of this well-conserved termination factor, which have evolved in this human pathogen.