Fig. 5. Olig1-DTA-mediated cell ablation is specific to the Olig1-Cre expression domain. (A-E,G-K) Expression of Irx3 and Shh (A,E) is largely unchanged in Olig1-DTA embryos (G,K). Pax6 expression in the p2 and more dorsal domains of Olig1-DTA embryos is unchanged, but, normally, weak expression in the pMN domain is not detected in Olig1-DTA embryos (B,H). Nkx6.1 and Nkx2.2-expressing p3 progenitor cells (A,C,D) are missing in Olig1-DTA animals (G,I,J). (F,L) The ventral spinal cord patterning defect at E10.5 is summarized in the schematics. (M-O) Lineage analysis using Olig1-Cre and Rosa26-eYFP indicates that the Nkx2.2⁺ p3 domain has expressed Olig1 (Cre) prior to E10.5. (P-R) The numbers (mean±s.d., left hemisection) of p2 domain-derived Chx10⁺ V2 interneurons are not significantly different in control (P) and Olig1-DTA (Q) embryos. Scale bars: in O, 50 µm for M-O; in K, 100 µm for A-E,G-K; in Q, 100 µm for P,Q.