Figure 2

miR-143/145 directly regulate ERBB3 expression at the post-transcriptional level. (A and B) Western blot analysis of ERBB3 protein levels in MCF-7 (A) and MBA-MD-231 (B) cells treated with pre-miR-control, pre-miR-143, pre-miR-145 or both pre-miR-143 and pre-miR-145 and in cells treated with anti-miR-control, anti-miR-143, anti-miR-145 or both anti-miR-143 and anti-miR-145. Left panel: representative image; right panel: quantitative analysis. (C and D) Quantitative RT-PCR analysis of ERBB3 mRNA levels in MCF-7 (C) and MBA-MD-231 (D) cells treated with pre-miR-control, pre-miR-143, pre-miR-145 or both pre-miR-143 and pre-miR-145 and in cells treated with anti-miR-control, anti-miR-143, anti-miR-145 or both anti-miR-143 and anti-miR-145. (E) Direct recognition of the ERBB3 3’-UTR by miR-143/145. MCF-7 cells were co-transfected with firefly luciferase reporters containing either wild-type (WT) or mutant (Mut) miR-143/145 binding sites in the ERBB3 3’-UTR and pre-miR-control, pre-miR-143, pre-miR-145 or both pre-miR-143 and pre-miR-145, or with anti-miR-control, anti-miR-143, anti-miR-145 or both anti-miR-143 and anti-miR-145. Twenty-four hours after transfection, the cells were assayed using a luciferase assay kit. The results are displayed as the ratio of firefly luciferase activity in the miR-143/145-transfected cells to the activity in the control cells. * P < 0.05; ** P < 0.01.