Figure 1.

Targeted deletion of β-catenin in odontoblasts by OC-Cre transgene. (A) Genotyping of Ctnnb1^fl/fl and OC-Cre;Ctnnb1^fl/fl mice performed by polymerase chain reaction. Histological sections of the mandible first molar (B-E) and the incisor (F and G) from Ctnnb1^fl/fl (B, D and F) and OC-Cre;Ctnnb1^fl/fl(C, E and G) mice were stained with antibodies against β-catenin (red) and K14 (green). The sections were counterstained with DAPI. Cytoplasmic and nuclear β-catenin was detected throughout the odontoblasts of the molar and incisor (B, D and F), with its highest expression within the pre-odontoblasts and the frontier HERS at the apical portion of molar root (B and D), but in mutant teeth, β-catenin was absent from the pre-odontoblasts in the apical portion of the molar and in pulp mesenchyme of the incisor (C, E and G). White arrows indicate signals condensed in pre-odontoblasts, and yellow arrows indicate pre-odontoblasts lined along HERS with absence of signals. OD(c), crown odontoblast; OD(r), root odontoblast; D, dentin; DP, dental pulp; AB, alveolar bone; OD(la), labial odontoblast; OD(li), lingual odontoblast. Scale bar: 60μm (B and C), 100μm (D-G).