Fig. 7. dA3 neurons and their derivative, the nucleus of the solitary tract, are not generated in Olig3 mutant mice. The alar plate of rhombomere 7 of control (A-C) and Olig3 mutant (D-F) mice at E10.5 (A,D), E13.5 (B,E) and E18.5 (C,F). Arrows indicate vagal motoneurons. (A,D) Immunohistological analysis using antibodies against Phox2b and Tlx3. In control embryos at E10.5, Phox2b⁺/Tlx3⁺ marked dA3 neurons (bracket), Phox2b⁺/Tlx3^- marked vagal motoneurons (arrow), and Phox2b^-/Tlx3⁺ marked dB3 neurons (bracket). In Olig3 mutant mice, dA3 neurons were absent. (B,E) In situ hybridization using a Phox2b-specific probe. In control embryos at E13.5, dA3 neurons (asterisk) were positioned dorsal to the vagal motoneurons (arrow). dA3 neurons were absent in Olig3 mutant mice. (C,F) Immunohistological analysis using antibodies against Tlx3, Phox2b and NF68. In Olig3 mutant mice, the Phox2b⁺/Tlx3⁺ neurons (inset in C) of the nucleus of the solitary tract were absent, but vagal motoneurons (arrows) were present. Scale bars: 100 µm in D,E; 200 µm in F.