Figure 2. Expression of Scube3 and Shh at later stages of craniofacial development.

Radioactive in situ hybridization on frontal sections. (A–E) Scube3 expression. (A, B) At E13.5, expression is seen in ectoderm of the bud stage tooth buds, early palatal shelves and tongue; (C) At E14.5, expression is intense in the cap stage tooth germ; (D, E) At E15.5, strong expression continues in ectodermal tissues of the developing teeth, the vibrissae and cartilaginous condensations of the nasal cavity. (F–J) Shh expression. Regions of overlap are between Shh and Scube3 are indicated by red arrows and include: (F, G) At E13.5, ectoderm of the early tooth buds and palatal shelves; (H) At E14.5, cells of the enamel knot within the cap stage tooth germs; (I–J) At E15.5, within the internal enamel epithelium of the bell stage tooth germs and the vibrissae. mdi, mandibular incisor tooth germs; mdm, mandibular molar tooth germs; mxi, maxillary incisor tooth germ; mxm, maxillary molar tooth germs; nc, nasal capsule; ps, palatal shelf; t, tongue; vi, vibrissae.