Competition assay. The binding between miR-224 and SLC4A4 3′-UTR was competed with increasing concentrations of unlabeled anti-miR-224. Probe miR-224* was incubated with SLC4A4 3′-UTR either in the presence (lanes 6–8) or the absence of anti-miR-224 (lane 2). Lanes 3–5 represent the binding between miR-224* and anti-miR-224. The intensity of the bands was quantified with ImageQuant software and normalized against the total radioactivity in each lane. It is represented the corresponding decrease in the binding between miR-224*:SLC4A4 3′-UTR, and it is expressed as a percentage of the control (lane 2) (lower panel).