text: Small molecules, proteins, and nucleic acids have been found to stimulate levels of frameshifting. For example, the mechanism of a negative feedback loop in the polyamine synthesis pathway is based on polyamine levels stimulating an increase in +1 frameshifts, which results in production of an inhibitory enzyme. Certain proteins which are needed for codon recognition or which bind directly to the mRNA sequence have also been shown to modulate frameshifting levels. MicroRNA (miRNA) molecules may hybridize to a RNA secondary structure and affect its strength.