Expression of Sfrp2 at E15.5. Sfrp2 is expressed in the VP and layer V neurons of the cortex (A, E, arrows). In Gsh2 mutants, the VP expression domain is expanded (B, F , arrowheads) but reduced in the lateral cortex (B, F, arrows). In Sey mutants, VP expression of Sfrp2 is missing (asterisks) and layer V expression is drastically reduced (arrows) (C, G). In Sey/Gsh2 double mutants, Sfrp2 expression is not restored in the VP (asterisks), and is severely reduced in the lateral cortex (arrows) (D, H). n numbers are as follows: controls, n= 6; Gsh2−/−, n= 4; Sey/Sey, n= 4; Sey/Sey;Gsh2−/−, n= 4. Scale bar: 200 μm.