Fig. 3. Marker analysis of Cripto^3loxP/null embryos. (A) Expression of Shh in wild-type and two Cripto^3loxP/null littermates at 8.25 dpc. Expression in the rostral diencephalic ventral midline, ventral midline and hindgut is completely (arrow) or partially (arrowheads) absent in the less severely affected Cripto^3loxP/null embryo (middle) and is abolished in the more severely affected embryo (right). (B) Expression of Hex in the anterior definitive endoderm at 7.5 dpc is lost in a Cripto^3loxP/null littermate. (C) En1 expression around the midbrain-hindbrain boundary in both wild-type and Cripto hypomorph embryos. (D) Six3 marks the ventral forebrain but is absent in a Cripto^3loxP/null littermate. (E,F) Fgf8 is expressed in the telencephalic commissural plate and the midbrain/hindbrain boundary (E), but is absent from the anterior end of a Cripto^3loxP/null embryo (F). Scale bars: 500 µm. cp, commissural plate; hg, hindgut; mhb, midbrain-hindbrain boundary; rdvm, rostral diencephalic ventral midline; vfb, ventral forebrain; vm, ventral midline.