Fig. 7.

Shh is not necessary to regulate Foxg1 expression in the telencephalon. E8.5 control (A,C,E,G) and Shh^–/– (B,D,F,H) embryos were analyzed for the expression of Six3 (A,B) and its target genes Wnt1 (C,D), Foxg1 (E,F) and Wnt8b (G,H). Although the midline remains fused in Shh^–/– embryos (F,H, arrows), no obvious changes in gene expression are observed. Six3 and Foxg1 are expressed in the ANE of Shh^–/– embryos (B,F) at a comparable level to that of control embryos (A,E). Consistently, Wnt1 and Wnt8b expression is restricted to the forebrain/midbrain boundary of control (C,G, arrowheads) and mutant (D,H, arrowheads) embryos. A, n=4; B, n=3.