Project PXD015051: "Identification of an RNA sponge that controls the levels, processing and efficacy of the RoxS riboregulator of central metabolism in B. subtilis"

Only a few small regulatory RNAs (sRNAs) have been characterized in B. subtilis, the paradigm of Gram-positive bacteria, and one of the major challenges is target identification. Here we use global in vivo RNA psoralen cross-linking to identify RNA-RNA partners in Bacillus subtilis. Two sRNAs, RoxS and FsrA, play key roles in balancing the metabolic state of the cell in response to carbon sources and iron limitation, respectively. In this study, we identify new mRNA targets for both RoxS and FsrA, and a small RNA (S345/RosA) that is able to interact with both sRNAs. We report that RosA controls the maturation and degradation of RoxS and acts as a sponge to limit the efficacy of RoxS on its targets. Expression of RosA is catabolically repressed by the transcription factor CcpA. We provide evidence that the RosA/RoxS interaction plays a key role in regulating metabolism in response to a switches in carbon source.