Fig. 1. Characterization of neuronal subtypes that arise from Olig3⁺ cells in the mouse dorsal hindbrain. (A-E) Immunohistological analysis of Olig3⁺ cells on consecutive sections of the dorsal alar plate of rhombomere 7 at E11.5. Olig3⁺ cells were observed in a broad domain of the ventricular zone. See Fig. S1A in the supplementary material for an explanation of the sector displayed. Immunohistological analysis of (A) Olig3, Ki67 and Lbx1, (B) Olig3 and Math1, (C) Olig3 and Ngn1, (D) Olig3, Mash1 and Ptf1a, (E) Olig3 and Ptf1a. Note that D and E show the same section; in E, the Mash1 signal was removed, and the Ptf1a signal is shown in red. (F-H,J-L) Analysis of neuronal types generated by Olig3⁺ cells using genetic lineage tracing in rhombomere 7 (F-H) and rhombomeres 4-6 (J-L). Recombination was induced in Olig3^CreERT2/+; Rosa26R mice at E9.5 by tamoxifen; cells that expressed the active lacZ gene were identified using anti-β-Gal antibodies. Neuronal types were defined using antibodies against Lhx2/9 (F,J), Lhx1/5 and Foxd3 (G), Tlx3 (H,K), and Lhx1/5 and Lbx1 (L). Note that J and K show the same section, which was stained for β-Gal, Lhx2/9 and Tlx3; J and K display β-Gal/Lhx2/9 and β-Gal/Tlx3 signals, respectively. (I,M) The distinct dorsal ventricular zones and neuronal subtypes of rhombomeres 7 (I) and 4-6 (M) (Sieber et al., 2007). Scale bars: 50 µm.