Fig. 5. The armadillo domain mediates neurogenesis promoted by ß-catenin and RA acts synergistically to enhance ß-catenin-mediated neurogenesis. Cells were seeded at high (10⁶ cells/ml, HD) or low densities (10⁵ cells/ml, LD) and treated with or without RA (cells in panels C,G,K,O were grown in KOSR media, see Materials and methods). Cells were fixed and stained 3-4 days post-plating with ß-tubulin 3 (green) and counterstained with Hoechst dye (blue). (A-D) Cells transfected with empty vector. (E-H) Cells transfected with ß-catenin Armadillo. (I-L) Cells transfected with ß-catenin C. (M-P) Cells transfected with ß-catenin N. The armadillo domain of ß-catenin, but not the C terminus, was required to overcome density-dependent inhibition of neurogenesis.