Fig. 7. Pax6 overexpression does not alter the expression profile of cortical regionalization markers. (A,B) Immunohistochemistry on sagittal sections through the cortex of (A) wild-type and (B) PAX77⁺ E12.5 embryos showing the expression of Emx2. The gradient of Emx2 expression is conserved in the cortex of PAX77 mice and overall levels are not reduced. (C,D) Immunohistochemistry on horizontal sections through the cortex of (C) wild-type and (D) PAX77⁺ E16.5 embryos showing the expression of Ephrin B2 in the right hemisphere. In the wild-type embryo, Ephrin B2 is strongly expressed in a caudal domain (arrowhead shows the anterior limit of the Ephrin B2 caudal expression domain). This caudal domain is present and does not appear contracted in the PAX77 cortex. (E,F) In situ hybridizations on sagittal sections through the forebrain of (E) wild-type and (F) PAX77^+/+ E18.5 embryos showing the expression of Id2 mRNA. In the wild-type embryo, Id2 is strongly expressed in layers 2 and 3 in an anterior domain (black arrow shows the posterior limit of this domain), and in layer 5 in a caudal domain (white arrowhead shows the anterior limit of this domain). The expression of Id2 appears unaltered in the PAX77 cortex. Scale bars: 200 µm in A-C; 0.5 mm in D-H.