Widespread Genetic Switches and Toxicity Resistance Proteins for Fluoride

Fluoride Riboswitch Riboswitches are found in prokaryote and eukaryote messenger RNAs (mRNAs), where they regulate expression of the linked mRNA through ligand binding and conformational change. Baker et al. (p. 233 , published online 22 December) analyzed the binding properties of the “ crcB motif” found in the noncoding RNA at the 5′ end of a diverse collection of prokaryotic genes. A crcB motif from Pseudomonas syringae was capable of selectively sensing the very small and highly charged fluoride ion. Some of the crcB and eriC genes associated with the fluoride riboswitch showed evidence of being fluoride transporters. The bacterium Methylobacterium extorquens DM4, which can use halogenated hydrocarbons as an energy source, was found to encode at least 10 fluoride riboswitches in its genome.