A small RNA molecule that controls whether bacteria coalesce into biofilms has a surprising mode of action.
Small RNAs are known to regulate gene expression by binding to target messenger RNAs, typically blocking their translation into proteins. A team led by Gisela Storz at the US National Institutes of Health in Bethesda, Maryland, and Poul Valentin-Hansen at the University of Southern Denmark in Odense found that a small RNA produced by Escherichia coli also binds to a target protein. The binding activates synthesis of a compound needed to form a biofilm.
Mutant bacteria in which this RNA–protein binding was abolished produced less of the compound and were less able to form biofilms. The results suggest that this small RNA tunes the protein's activity by interacting with it directly.
Genes Dev. http://dx.doi.org/10.1101/gad.214734.113 (2013)