Figure 1: RA-treated hES cells express epithelial markers, but do not form organized structures when cultivated under organotypic conditions. Representative phase contrast images depicting the cell and colony morphology of hES cells after treatment with hES growth medium supplemented with DMSO (A) or RA (B). RT-PCR detection of neural or epithelial markers for untreated, DMSO-treated, and RA-treated samples (C). Results are representative of three independent experiments. Histological analysis of tissue generated from DMSO-treated hES cells revealed formation of well-organized pseudostratified columnar epithelia (D). Culture of RA-treated hES cells resulted in disorganized structures with limited areas of stratified epithelia (E). Scale bar represents 500 μm (A and B); 50 µm (D and E).