Fig. 3. Pattern formation of the neural plate of murine Fgf8^b/b embryos is largely normal. (A-J) Expression of region-specific markers, as indicated to the left, in the anterior neural plate of wild-type and Fgf8^b/b embryos: Otx2, telencephalon and mesencephalon; Gbx2, rhombomere 1 (r1); Fgf8, r1; En1, mesencephalon and r1; Shh, head process and axial mesoderm. Black arrows mark the mid-hindbrain junction. Arrowheads in A,B,I and J demarcate Krox20 expression in r3 and r5 (A,B) and Hoxb1 expression in r4 (I,J). Notice that the head process (red arrow; I,J) appears abnormal in the mutants.