(a) Directed differentiation into the three germ layers of the dox-inducible Rb7LP cell line, which expresses the active non-phosphorylatable form of Rb, and compared with control and 2% DMSO-treated cells. (b) Quantitative RT-PCR analyses of the expression levels of Rb and pluripotency genes in Rb7LP cells without DOX (Rb7LP control) and with a 24h DOX treatment (Rb7LP+Dox). (c) Protein expression of the truncated Rb-GFP protein and pluripotent markers, Oct4 and Nanog, by western blotting. GAPDH serves as a loading control. (d) Quantitative RT-PCR for lineage-specific genes and (e) immunostaining for pax6 (ectoderm), brachy (mesoderm), and sox17 (endoderm) following directed differentiation. Error bars, s.d. of 4–6 biological replicates. Scale bars, 100 μm. * p ≤ 0.05, ** p ≤ 0.01 under one-way ANOVA; Tukey’s test for multiple comparisons.