Figure 1. Photomicrographs of lower first molars on PN6d. (a) WT mouse. (b) Hyp mouse. Widened predentin can be seen. (c) OC mRNA expression in WT mouse specimen. Reactivity is observed in odontoblasts (arrowheads), which weakened with the progress of the cytodifferentiation and mineralization processes (large arrowheads). (d) OC mRNA expression in Hyp mouse. The distribution of signals (arrowheads) is similar to that of WT mice. (a,b) HE staining; (c,d) in situ hybridization. AB, ameloblasts; D, dentin; E, enamel; OB, odontoblasts; PD, predentin; PO, pre-odontoblasts.