The downregulatory effects of let-7a, miR-9, and miR-129-5p are mediated via specific sequences in the human FOXP2 3' UTR. (A) miR-9, miR-19b, miR-140-5p, miR-200a, let-7a, miR-129-5p, miR-582-5p, and miR-892a significantly repressed luciferase activity when co-transfected with a reporter construct containing a wild-type FOXP2 3' UTR, but had no effects when co-transfected with a reporter construct containing no 3' UTR. (B) Mutations in the binding sites for let-7a, miR-9, and miR-129-5p in the human FOXP2 3' UTR. Mutated nucleotides are in lower case letters. (C) Mutations in both the two binding sites for let-7a, miR-9, and miR-129-5p in the FOXP2 3' UTR abolished the repressive effects of these miRNAs in luciferase reporter assays. Transfection was performed three times (n'='3) for each miRNA, and luciferase assays were performed in duplicate. To control for transfection efficiency, Renilla luciferase activity was normalized to the internal control firefly luciferase activity. Error bars'='SEM; *p<0.05, **p<0.01, and ***p<0.001, Tukeys Honest Significant Difference test.