Differentiation of P19 embryonal carcinoma cells to neuron-like cells. A. In vitro differentiated P19 cells express markers of mature neurons. 3 μg samples of total protein from days 0, 2, 4, 7, 9 and 11 of the developmental program were fractionated by SDS-PAGE, transferred to a PVDF membrane and probed with various antisera: β3-tubulin, marker for mature neurons; Oct4, a marker for pluripotent stem cells; GAPDH, a loading control. B. 3 μg samples of total P19 cell protein from days 0 or 11 or from a mouse brain homogenate (Br) were fractionated by SDS-PAGE and probed by immunoblotting with antibodies directed against β3 tubulin and GFAP (glial fibrillary acidic protein). C. Undifferentiated P19 cells (day 0) and day 11 NLCs were subjected to flow cytometry to analyze the distribution of cells responding to a glial marker GFAP, and a neuronal marker β3-tubulin as indicated.