Fig. 4. Immunohistochemical analysis. Double immunostaining of CK14 (A,D,G) and Notch2 (B,E,H) in the epithelial sheaths of mutant incisors grown under kidney capsules (A-I), and staining for Notch2 in lower incisors of wild-type mice at PN d1 (J). (A-I) Both labial and lingual HERS are strongly labeled by anti-CK14 and Notch2 antibodies. Fragmentation of the dental epithelium (arrowheads), similar to Malassez epithelial rests, is also recognizable at the dentin surface. Arrows indicate non-specific staining against calcified dentin. (D-F,G-I) Higher magnifications of the labial HERS and of the lingual HERS,, respectively, in A-C. (C,F,I) Phase pictures of A,B, D,E and G,H, respectively. (J) Immunostaining for Notch2 at the apical end of PN d1 mouse lower incisors. Notch2 is expressed in the OEE and the stellate reticulum at the labial side (J, smaller arrows), and in the epithelial sheath at the lingual side (J, larger arrow). Scale bars: 25 µm in A-C; 10 µm in D-I; 200 µm in J.