Figure 5

Amelotin expression during amelogenesis in the iguanid lizard Anolis carolinensis . Longitudinal (A-H, K) and transverse (I, J) sections of demineralized lower jaws (oral cavity on the top). In this lizard the dentition is heterodont: anterior teeth are monocuspid (A-F, I, J) and posterior teeth are tricuspid (G, H, K). A, C, E, G, I: Histology, toluidine blue staining; B, D, F, H, J, K: in situ hybridization with AMTN antisense mRNA probe; K: Negative control with AMTN sense mRNA probe. A, B: Late cytodifferentiation. AMTN transcripts are weakly labelled in the ameloblasts lining the predentin matrix. C, D: Early deposition of enamel matrix. AMTN transcripts are detected in the well-polarized ameloblasts facing the enamel matrix (dark blue in C). E, F: Enamel deposition. The ameloblasts along the deposited enamel matrix are well labeled. G, H: Enamel maturation. AMTN mRNAs are strongly identified in the ameloblasts facing the enamel layer. The latter is well mineralized with the exception of the regions covering the minor mesial and distal cusps. I, J: AMTN expression is still detected during late maturation stage before the tooth attachment process begins. am: ameloblast, db: dentary bone; de: dentine; en: enamel; es: demineralized enamel space; ide: inner dental epithelium; od: odontoblasts; ode: outer dental epithelium; oe: oral epithelium; pc: pulp cavity; pd: predentin; sr: stellate reticulum. Scale bars = 50 μm.