Figure 10.

Model for a dual role of Hfq in repressing IS 10 transposase translation. When IS 10 is present in single copy (left side), transposase expression is not subject to antisense control by RNA‐OUT. Hfq binding to the RBS in RNA‐IN represses translation by preventing ribosome binding (‘stoichiometric’ repression). Multi‐copy IS 10 is subject to antisense control by increased concentrations of RNA‐OUT (right panel). Hfq may still participate in stoichiometric repression but also facilitates antisense pairing in a ‘catalytic’ manner. Hfq binding to RNA‐IN and RNA‐OUT alters RNA secondary structure (not shown for RNA‐IN), exposing sequences involved in pairing.