A. Sequences of Ranilla/Firefly Luciferase psiCHECK2 constructs under regulation of PGR 3'UTRs that were used for transient reporter assay experiments. WT and Mutant (Target-deletion) alleles for each microRNA binding site are presented. B. Luciferase activity 48 hours following co-transfection with miRNA-181a in combination with either of the PGR 3'UTR constructs in HeLa cells. C., D. Luciferase activity 24 hours following co-transfection with miR-23a or miR-26b, respectively, in combination with the indicated PGR 3'UTR constructs in MCF-7 cells. Values are presented as mean ± SEM, n = 3, *p < 0.05, **p < 0.01, two-tailed student's t-test.