Enhanced STAT3 activity promotes generation of RG-like cells in in vitro culture. A–D, P19 cells were grown as embryonic bodies with retinoic acid and CNTF. Cells were replated and harvested at 2 and 4 DIV. Cells were labeled with BLBP (red) and DAPI (blue). E, Quantification of BLBP-expressing cells (n = 3 cultures, n = 4–5 coverslips for each condition). F, Measurement of BLBP transcript in cultures at 6 and 8 DIV by RT-PCR. G–J, L–O, Immunolabeling for RC2, nestin, Sox2, and Tuj1 in dissociated neurospheres at 1 or 3 DIV. K, P, Q, Quantification of cells expressing RC2 (K), nestin (P), and Tuj1 (Q) among the DAPI-stained cells (n = 3–4 cultures, n > 6 coverslips per condition). Only cells with processes longer than 50 μm were counted to ensure their identity. Error bars represent SEM. *p < 0.05, **p < 0.01, ***p < 0.001, unpaired Student's t test. Scale bars: (in D) A–D, 20 μm; (in O) G–J, L–O, 50 μm.