Fig. 6. ZLI is rescued in the Six3;Wnt1 double-null brain. Hematoxylin and Eosin staining of sagittal sections from E14.5 Wnt1-null (Six^+/+;Wnt1^-/-, A) and Six3^-/-;Wnt1^-/- (A') mouse brains. As indicated by Shh expression, the ZLI (arrow) is normally detected in the alar plate of Wnt1^-/- (B) and Six3^-/-;Wnt1^-/- brains (B'). Lhx2 and Tcf4 expression is detected in the thalamus of Wnt1^-/- (C,D) and Six3^-/-;Wnt1^-/- (C',D') brains. BF-2 and Dlx2 labeled the prethalamus, indicating the presence of these structures in the Wnt1^-/- (E,F) and Six3^-/-;Wnt1^-/- (E',F') brains. As revealed by Dlx2 and Nkx2.1 analyses, the hypothalamus was also present in Wnt1^-/- (F,G) and Six3^-/-;Wnt1^-/- (F',G') brains at E14.5. Models representing the Six3^+/+;Wnt1^-/- (H) and Six3^-/-;Wnt1^-/- (H') brains at this stage are included for clarity. The thalamus and prethalamus are rescued in Six3^-/-;Wnt1^-/- brains (H'). Anterior is to the right. ET, eminentia thalami; HY, hypothalamus; P, Pons; PT, prethalamus; T, thalamus.