Fig. 3. At E9.5, the expression domains of genes transcribed at the MHB is enlarged. Wholemount in situ hybridization showing the expression of Otx2 (A,B), Gbx2 (C,D), Fgf8 (E,F), En1 (G,H), Pax2 (J,K) and Wnt1 (L,M) and transcribed at the MHB, as indicated. At this stage of development (E9.5), the shift of the IsO, detected at E8.5 and shown in Fig. 2, is still evident (A-D), and the expression domains of the presented markers appear enlarged at the MHB of the mutant embryos (D,F,H,K,M). The embryos shown for Wnt1 are between E9.5 and E10.