For induction of MGE phenotype, differentiating spheres were initially treated with FGF8 (100 ng/ml) in KSR medium in the second week followed by FGF8 in N2 medium (DMEM-F12 medium supplemented with N2) in the third week. This treatment resulted in cultures enriched in MGE cells, as shown by the high proportion of Nkx2.1+ cells (Fig. 2a and e). For induction of CGE phenotype, differentiating spheres were initially treated with FGF19 (100 ng/ml) in KSR medium in the second week followed by FGF19 in N2 medium in the third week. This resulted in cultures enriched in CGE cells, as indicated by the high proportion of CoupTFII+ cells (Fig. 2b and e).
