Fig. 2. Defining the limits of GFP expression in Dbx1-iCrexRosa26-GFP offspring. (A-I) Serial 10-µm sections through the E10.5 upper thoracic spinal cord were subjected to in situ hybridization with various probes (A,B,D,E,H), or immunohistochemistry for GFP or Pax7 (C,F,G,I). In situ hybridization probes are indicated. (G) Double immunolabelling for Pax7 (red) and GFP (green). Brackets (A-C) indicate the approximate limits of the GFP expression domain. Horizontal lines indicate the ventral (D-F) or dorsal (G-I) limits of GFP expression. The ventral limit corresponds approximately to the p2/p1 boundary, and the dorsal limit to the dP5/dP4 boundary. Scale bar: 50 µM.