Figure 3. The re-expression of miRNAs down regulated in immortalized MEF reduces cell proliferation. (A) Quantification of miR-20a, miR-21, miR-28, miR-290 and miR-34a per passage normalized to that of MEF at passage 0. Dashed lines indicate the transition from passage 5 to 6. (B) Cell cycle phase distribution (%) of MEF from p1 to p5. (C) Population cell doubling of immortalized MEF after transfection of miR-NC, miR-20a, miR-21, miR-28, miR-290 and miR-34a. Each bar represents the mean ± SD of three biological replicates (*=p<0.05). (D) Expression of ASF/SF2 protein in primary (p3 and p5) and immortalized (p10) MEF. The value reported under each lane represents the average of two independent experiments. (E) Expression of ASF/SF2 after the transfection of immortalized MEF with either miR-NC or miR-28. The value reported under each lane represents the average of two independent experiments.