Fig. 11. Expression of molecular markers in wild-type and littermate knockout mice at E12.5. Shown are the in situ hybridization staining patterns of sagittal (A-C) and coronal sections through wild-type (+/- or +/+) and knockout (-/-) heads at E12.5. The blue digoxigenin staining indicates the presence of the specific transcript being evaluated. Note that Fgf8 expression is maintained in the isthmus, infundibulum, lamina terminalis and septum, but is lost in the choroid plexus of the forebrain (C,C'). The asterisks in D' and E' indicate the decrease in Msx2 expression (D,D') and the lack of Wnt3a expression (E,E') in the dorsal midline of the knockout embryos. Scale bars: 500 µm. LGE, lateral ganglionic eminence; MGE, median ganglionic eminence; ch, choroidal plexus; cx, cerebral cortex; ep, epiphysis; IN, infundibulum; lt, lamina terminalis; is, isthmus; hem, cortical hem; DT, dorsal thalamus; se, septum; me, mesencephalon; cb, cerebellum.