Regulatory RNAs in Bacillus subtilis: a Gram-Positive Perspective on Bacterial RNA-Mediated Regulation of Gene Expression
SUMMARYBacteria can employ widely diverse RNA molecules to regulate their gene expression. Such molecules includetrans-acting small regulatory RNAs, antisense RNAs, and a variety of transcriptional attenuation mechanisms in the 5′ untranslated region. Thus far, most regulatory RNA research has focused on Gram-negative bacteria, such asEscherichia coliandSalmonella. Hence, there is uncertainty about whether the resulting insights can be extrapolated directly to other bacteria, such as the Gram-positive soil bacteriumBacillus subtilis. A recent study identified 1,583 putative regulatory RNAs inB. subtilis, whose expression was assessed across 104 conditions. Here, we review the current understanding of RNA-based regulation inB. subtilis, and we categorize the newly identified putative regulatory RNAs on the basis of their conservation in other bacilli and the stability of their predicted secondary structures. Our present evaluation of the publicly available data indicates that RNA-mediated gene regulation inB. subtilismostly involves elements at the 5′ ends of mRNA molecules. These can include 5′ secondary structure elements and metabolite-, tRNA-, or protein-binding sites. Importantly, sense-independent segments are identified as the most conserved and structured potential regulatory RNAs inB. subtilis. Altogether, the present survey provides many leads for the identification of new regulatory RNA functions inB. subtilis.