Comparison of the wild type and transgenic Ndn expression profiles in E10.5 and E12.5 mouse embryos. In situ hybridization was performed with an Ndn riboprobe on sagittal sections of wild type (A, B, C, H), Tg92mat-Ndn+/-pat (D, E, F, I) and Ndn+/-pat (G) embryos. The absence of Ndn signal in the E10.5 Ndn+/-pat embryo (G) demonstrates the specificity of the Ndn riboprobe. Similar expression profiles are shown in the infundibulum recess (ir) of E10.5 embryos (A, D), in the preplate of the telencephalic epithelium (pp) and in the dorsal root ganglia (drg) of E12.5 embryos. Note that no hybridization signal is detected in the transgenic Tg92mat-Ndn+/-pat E12.5 muscle (ms) (I) whereas endogenous Ndn is expressed in this tissue (H). rp, rathke pouch; tv, telencephalic vesicle.