Fig. 2. The floorplate is reduced in width in both mol^-/- and smu^-/- embryos. (A-C) Lateral views of the floorplate in the trunk of living wild-type, mol^-/- and smu^-/- embryos. Cuboidal floorplate cells are present in all embryos, although the cells are increased in size in mol^-/-. (D-F) Dorsal views of foxa expression in the hindbrain floorplate. In the mol^-/- and smu^-/- mutants, expression is reduced from a six cell wide band to a one to three cell wide band (black lines). Additionally, gaps of expression are present in the mol^-/- mutant. (G-I) Dorsal views of foxa2 expression in the head. Midline expression is narrow in both the mol^-/- and the smu^-/- mutant, and additionally is patchy in the midbrain and hindbrain in the mol^-/- mutant. e, endoderm; fp, floorplate; hy, hypochord; nc, notochord; ZLI, zona limitans intrathalamica.