Validation of 3′UTR-miRNA interactions. (A) Normalized luciferase activity of K562 cells nucleofected with the indicated miRNA mimics and 3′UTR luciferase reporter vectors. Firefly luciferase activity was measured 48 hours after nucleofection and normalized to Renilla luciferase activity. Values are reported as mean ± SEM; *P < .05 vs miRNA mimic negative control (Neg-mimic). Results come from 3 independent experiments performed in duplicate. (B) Graphical representation of mRNA-miRNA interactions validated by means of 3′UTR luciferase reporter assays. Solid lines (validated interactions); dashed lines (not validated interactions). (C) Results of the luciferase reporter assays performed with wild-type and mutant 3′UTR. Assays were carried out only for the 3′UTR-miRNA interactions previously validated (A). Each bar represents the luciferase activity upon miRNA overexpression normalized on the value of the same 3′UTR luciferase vector upon Neg-mimic transfection. Values are reported as mean ± SEM; *P < .05 vs mutant 3′UTR. Results come from 3 independent experiments performed in duplicate.