Fig. 4 Vax1 mutant MGE shows reduced levels of Dlx proteins and loss of Gsh1 expression. Coronal sections from control (A,C,E,G) and Vax1 mutant (B,D,F,H) telencephalons at E13.5 analyzed by immunohistochemistry (A-F) and in situ RNA hybridization (G,H). Dlx proteins are expressed in the VZ and SVZ of wild-type SA, LGE and MGE (A,C) in a gradient similar to that of Vax1 mRNA. In Vax1^-/- ganglionic eminences, Dlx expression is reduced in the MGE and presents a shallower graded pattern in the LGE (B,D). Dlx-positive cells are reduced in the cortex of mutant mice (arrowheads in E and F). In the MGE of mutant brains, Gsh1 expression is almost completely lost (compare G with H). LGE, lateral ganglionic eminence; LV, lateral ventricle; MGE, medial ganglionic eminence; SA, septal area; SA^*, presumptive aplastic septal area; SVZ, subventricular zone; VZ, ventricular zone. Scale bars: 500 µm in A,B,G,H; 100 µm in C-F.