FIGURE 1.

Regulation of csRNAs expression by TCS CiaRH after exposure of the cell to extracellular stimuli. First, the sensor CiaH detects extracellular stimuli such as pH variation and antibiotics exposure. CiaH transduces the signal to the regulator CiaR that interacts with promotor and allows csRNA expression. Then, csRNA interacts with target mRNA and allows or represses the translation. For example, in S. sanguinis, the csRNA1-1 interacts with the PilT mRNA and represses the translation of PilT protein inducing the reduction of biofilm formation. In S. pneumoniae, csRNA1 combined with csRNA2 and csRNA3 allows the repression of ComC translation, which reduces the natural competence of bacteria.