Fig. 6. Lack of Otx2 and increased expression of Shh affect the expression of Nkx6.1 and Nkx2.2. (A-L) Shh (A,D,G,J), Nkx6.1 (B,E,H,K) and Nkx2.2 (C,F,I,L) immunodetection in the ventral midbrain of E10.5 and E12.5 En1^cre/+ and En1^cre/+; Otx2^flox/flox embryos (A-F), in the rostral hindbrain of E12.5 En1^cre/+ embryos (G-I), and in the ventral midbrain of E12.5 Otx1^cre/+; Otx2^flox/– embryos (J-L). The arrows in B,E,K indicate the ventral neuroepithelium where Nkx6.1 expression is lost, and the arrows in C,F indicate the ventral expansion of the Nkx2.2 domain. fp, floor plate; ABB, alar-basal boundary.