Fig. 3. Evc expression pattern. ß-gal activity at E11.5 (A,B), E12.5 (C), E13.5 (D), E15.5 (E-J) and in newborn (K-N) mice demonstrating expression in the mouth and tooth-forming areas and in the developing skeleton. The ossified centres of the long bones are not ß-gal-positive. E is a coronal vibratome section of the head of an embryo. H,I,J are sagittal paraffin sections of the head, lower jaw and vibrissae. (K,L) Absence of endogenous ß-gal activity in control (K) and expression of lacZ in the proximal nail bed in Evc^-/- (L, arrow) mice. (M,N) Vibratome sections showing growth plates of distal (M) and proximal (N) tibia of newborn mice. The blue signal in the bone marrow is background, as it was also detected in equivalent wild-type sections. Evc expression has the same distribution in heterozygotes and mutants from E12.5 to birth. All images relate to Evc^+/- embryos with the exception of newborn mice (L-N), which were Evc^-/-, and K which was wild-type. 1, lateral nasal process; 2, maxillary process; 3, mandibular process; e, eye; ns, nasal septum; nc, nasal capsule; jo, Jacobsos organ; ul, upper lip; oc, oral cavitity; ui, upper incisor; mx, maxilla; ma, mandible; mc, Meckel's cartilage; tb, temporal bone; li, lower incisor; dp, dermal papillae. Growth plate chondrocytes labelling: R, resting; P, proliferative; PH, prehypertrophic; H, hypertrophic; B, bone.