Figure 4From: All-trans retinoic acid promotes neural lineage entry by pluripotent embryonic stem cells via multiple pathwaysRA could not bypass the requirement for ERK signaling in neural specification. Monolayer differentiation of 46C ESCs in RA-treated cultures (N2B27 + 10-8 M RA) exposed to FGF receptor tyrosine kinase inhibitor SU5402 (5 μM), MEK1/2 inhibitors PD184352 (4 μM) or PD0325901 (4 μM), or to equivalent amounts of DMSO diluents. A, Cultures of monolayer differentiation, shown in phase contrast or stained for Sox1GFP; B, Typical FACS profile of Sox1GFP expression; C, Percentage of Sox1GFP+ cells scored by FACS; D, Cultures of monolayer differentiation, shown in stained for Oct4 or combination of Oct4 and Hoechst; E, Western blot analysis of Oct4 at day 5 under monolayer cultures; F, Western blot analysis of phosphorylated ERK1/2 and ERK1/2 at 12 h under monolayer cultures; G, RT-PCR for Elk1, one of the targets of ERK signaling; H, Q-PCR for Elk1 during monolayer differentiation. *, p < 0.05; **, p < 0.01. Scale bars: A, 40 μm; D, 80 μm.Back to article page