Fig. 4. Exogenous NGN1 and MASH1 promote sensory and autonomic neurogenesis, respectively, at 10 ng/ml BMP2. Cultures were infected with retroviruses encoding NGN1-IRES-GFP (A,C,E) or MASH1-IRES-GFP (B,D,F), grown for 3 days in 10 ng/ml BMP2 and triple-labeled with antibodies to BRN3A (A,B), PHOX2B (C,D) and GFP to detect infected cells (E,F; arrows). NGN1-infected cells that express BRN3A (A,E, arrows) do not co-express PHOX2B, while MASH1-infected cells that express PHOX2B (D,F, arrows) do not co-express BRN3A. (G,H) The percentage of cells infected with the indicated retroviruses that express BRN3A (G) or PHOX2B (H) is indicated. *P<0.05 indicates significantly different from control GFP-infected cells. Note that the percentage of NGN1-infected cells expressing PHOX2B in H (6%) is not significantly different from the GFP control (1%; one-way ANOVA followed by post-hoc analysis, HSD=1.33<4.34). The results were pooled from eight experiments. For additional data, see Fig. 6, Table 1 and Table 2.