A trans-Acting Riboswitch Controls Expression of the Virulence Regulator PrfA in Listeria monocytogenes

Edmund Loh (1) , Olivier Dussurget (2) , Jonas Gripenland (1) , Karolis Vaitkevicius (1) , Teresa Tiensuu (1) , Pierre Mandin (2) , Francis Repoila (2) , Carmen Buchrieser (3) , Pascale Cossart (2) , Jörgen Johansson (1)

1 Umeå University
2 UIBC - Interactions Bactéries-Cellules
3 Biologie des bactéries intracellulaires

Riboswitches are RNA elements acting in cis, controlling expression of their downstream genes through a metabolite-induced alteration of their secondary structure. Here, we demonstrate that two S-adenosylmethionine (SAM) riboswitches, SreA and SreB, can also function in trans and act as noncoding RNAs in Listeria monocytogenes. SreA and SreB control expression of the virulence regulator PrfA by binding to the 5'-untranslated region of its mRNA. Absence of the SAM riboswitches SreA and SreB increases the level of PrfA and virulence gene expression in L. monocytogenes. Thus, the impact of the SAM riboswitches on PrfA expression highlights a link between bacterial virulence and nutrient availability. Together, our results uncover an unexpected role for riboswitches and a distinct class of regulatory noncoding RNAs in bacteria.

Domaines: Sciences du Vivant [q-bio]

Edmund Loh, Olivier Dussurget, Jonas Gripenland, Karolis Vaitkevicius, Teresa Tiensuu, et al.. A trans-Acting Riboswitch Controls Expression of the Virulence Regulator PrfA in Listeria monocytogenes. Cell, 2009, 139 (4), pp.770-779. ⟨10.1016/j.cell.2009.08.046⟩. ⟨hal-02668223⟩