Gene expression of Cdk1, Cdk4, CCND1, PPARγ, and C/EBPα in siRNA-transfected cells. RNA was isolated at 36, 48, or 72 h post-siRNA transfection. Expression level for each gene was normalized against those of HSP90. Percentage value graphed was derived by comparing the average value of triplicates for each gene in each treatment group to its value in siCon cells at the same time point. (A) Expression of Cdk1, Cdk4, and CCND1 was downregulated in siCdk1-, siCdk4-, siCCND1-transfected cells, respectively. (B) Expression of Cdk1 was downregulated in both siCdk4- and siCCND1-transfected cells. Expression of Cdk4 was transiently downregulated in siCdk1 cells before it was upregulated, while expression of CCND1 was unchanged in siCdk1 cells. (C) Expression of C/EBPα was upregulated in siCdk1 cells, but transiently downregulated in siCCND1-transfected cells. (D) Expression of PPARγ was upregulated in siCdk1 cells, but transiently downregulated in siCdk4-transfected cells (n = 3). Color images available online at www.liebertpub.com/scd