MiR-188 regulates target genes expression through direct binding to their 3'UTRs. Sequences of miR-188 and predicted miR-188-binding sites at CCNA2, CCND1, CCND3, CCNE1, CDK2 and CDK4 3'UTRs. The mutant sequences (Mu) are identical to the wild-type (WT) except the mutated nucleotides are shown in red. Luciferase vectors were generated by inserting WT or Mu 3'UTRs of target genes into pmirGLO plasmid. The reporter vectors were co-transfected with miR-188 or miR-NC. Relative luciferase activity was determined at 24 h after transfection. Results shown are means ± SD of three independent experiments (Student t test, **p < 0.01).