Fluoride-Controlled Riboswitch-Based Dampening of Gene Expression for Cloning Potent Promoters.

Bioreporter systems based on detectable enzyme activity, such as that of beta-galactosidase or luciferase, are key in novel bacterial promoter discovery and study. While these systems permit quantification of gene expression, their use is limited by the toxicity of the expressed reporter enzymes in a given host. Indeed, the most potent promoters may be overlooked if their activity causes a lethal overproduction of the reporter genes when screening for transcriptional activity of potential promoter sequences with the cassette.

GcvB small RNA uses two distinct seed regions to regulate an extensive targetome.

GcvB small RNA is described as post-transcriptional regulator of 1-2% of all mRNAs in Escherichia coli and Salmonella Typhimurium. At least 24 GcvB:mRNA interactions have been validated in vivo, establishing the largest characterized sRNA targetome. By performing MS2-affinity purification coupled with RNA sequencing (MAPS) technology, we identified seven additional mRNAs negatively regulated by GcvB in E.