Figure 2.

Downregulation of CDK1 by RNAi effectively abrogates CDK1 expression and induces the accumulation of hESC at the G2 phase of the cell cycle. (a) Quantitative RT-PCR analysis for expression of CDK1 from 24 to 120 h post transfection. Results are presented as average±S.E.M. (n=3). T-test analysis was carried out to assess differences in gene expression between the control and CDK1 siRNA group, *P<0.05. (b) Western blot analysis of CDK1 expression. β –Actin was used as the loading control. The data shown are representative of six independent western blots carried out in H9 hESC line. (c) Graphical representation of the ModFit analysis of cell cycle distribution in the control and CDK1 siRNA group, 48 h post transfection with siRNAs. Results are presented as average±S.E.M. (n=6). T-test analysis was carried out to assess the differences in gene expression between the control and CDK1 siRNA group, *P<0.05. (d) Flow cytometric histograms showing cell cycle distribution in control and CDK1 siRNA groups. The percentage of cells in each stage of the cell cycle is indicated in the top right corner of flow histogram. Data are representative of at least six independent experiments. (e) Phase-contrast images of hESC transfected with control and CDK1 siRNAs (upper and lower panel respectively) at 2, 3 and 4 days post transfection. Scale bar=25 μm