A neuronal reporter is expressed in differentiated cells obtained from ES cells. ES cells expressing GFP as a fusion protein with tau were fluorescent after differentiation for 10 d to cells with the morphology of neurons (A, in green) and stained for β-III tubulin (B, in red). Merged images are shown in low power in C and high power in D with scale bars indicating 50 microns. Both floating spheres (FS) and attached proliferating cells (P) are shown in E to express an array of developmental regulators (Wnt3a, Wnt1, Frz1, Frz7, BMP4, BMP7, Notch1, Jag1, Jag2). Neurons differentiated from neural progenitors (D) had similar expression of neuronal markers, NF-M, TrkC and MAP2 as spiral ganglion neurons (SG).