Fig. 1. Temporal and spatial changes in the specification of neurons in the dorsal spinal cord. (A-C) Immunohistological analysis of dorsal spinal cords of wild type mice at stage E10.5-E12.5 using antibodies directed against Mash1 (blue), Lbx1 (red) and Tlx3 (green). The d4 and d5 (early) and dL (late) progenitor domains are indicated, as well as the dI3-5, dILA and dILB neuronal subtypes generated. Immunohistological analysis of spinal cords of wild-type animals at stage E12.5 using antibodies directed against (D,D') Tlx3 (red) and Pax2 (green), (E) Gsh1/2 (green) and Lbx1 (blue), (F) Mash1 (green), Olig3 (red) and Lbx1 (blue), (G,G') Mash1 (red) and Gsh1/2 (green), (H) Ptf1a (green) and Lbx1 (blue), and (H') Ptf1a (green), Lhx1/5 (blue) and Lmx1b (red). (I) Schematic display of the expression of transcription factors in progenitors of the alar plate and in dorsal neurons at E12.5. The yellow and orange bars indicate progenitor domains that express Ngn1 and Math1, respectively. Scale bars: 100 µm in A-H; 20 µm in D',G',H'.