Subcellular localization of beta-catenin and cadherin expression in the cap-stage enamel organ of the mouse molar.
We analyzed the subcellular distribution of beta-catenin in the cap-stage enamel organ and compared it with the expression of E- and P-cadherin by using confocal laser microscopy. The amounts of the molecules in the cytoplasm and the nucleus showed regional variations in the enamel organ, whereas cell surface-associated beta-catenin was ubiquitous. In both the enamel knot and the inner dental epithelium, beta-catenin was detected in the cytoplasm and in the nucleus. However, the amount of nuclear beta-catenin was apparently higher in the enamel knot than in the inner dental epithelium. P-cadherin also gave a stronger signal in the enamel knot than in other parts of the enamel organ. In the stellate reticulum, where E-cadherin was preferentially expressed, as well as in the cervical loop and outer dental epithelium, beta-catenin was localized in the cytoplasm but not in the nucleus. The nuclear localization of beta-catenin in the enamel knot suggests a specific activation of the canonical Wnt signaling pathway. A coincident upregulation of P-cadherin was observed in this area. Altogether, these observations suggest the possibility of a linkage between cell adhesion and Wnt signaling in the enamel knot.
Department of Oral Anatomy, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, 061-0293, Hokkaido, Japan. obara@hoku-iryo-u.ac.jp
Nobuko
N
Obara
Hervé
H
Lesot
D000818:Animals; D015820:Cadherins / Q000378:metabolism*; D002448:Cell Adhesion; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004658:Enamel Organ / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D051379:Mice; D008963:Molar / Q000378:metabolism*; D015398:Signal Transduction; D014018:Tissue Distribution; D015534:Trans-Activators / Q000378:metabolism*; D015854:Up-Regulation; D051153:Wnt Proteins; D051176:beta Catenin
C495267:CTNNB1 protein, mouse; D015820:Cadherins; D003598:Cytoskeletal Proteins; D036341:Intercellular Signaling Peptides and Proteins; D015534:Trans-Activators; D051153:Wnt Proteins; D051176:beta Catenin; C502406:fat1 protein, mouse