Histological and immunohistochemical analyses of molar tooth germ in enamelin-deficient mouse.
Amelogenesis imperfecta (AI) is associated with mutations in a number of genes, including AMELX and ENAM. However, the precise mechanism leading to enamel malformation in different AI types remains to be elucidated. In the present study, we investigated morphological change in tooth germ obtained from ENAM-mutant mice (Enam(Rgsc521) homozygotes) as a model for human AI using histological and immunohistochemical methodologies. The results showed that ameloblasts detached from developing dentin and lost cell polarity in mutant mice at post-natal day 3. Cyst-like structures, including amelogenin-immunopositive materials, were observed between these detached cells and the dentin. No enamel-like structure, however, was observed in the cusp of the crown. These results suggest that enamelin acts as an adhesion molecule and is involved in ameloblast cell differentiation during the early stages of tooth development.
Sawada
Takashi
T
Department of Ultrastructural Science, Tokyo Dental College, Masago, Mihama-ku, Chiba, Japan. sawada@tdc.ac.jp
Sekiguchi
Hiroshi
H
Uchida
Takashi
T
Yamashita
Haruto
H
Shintani
Seikou
S
Yanagisawa
Takaaki
T
D000565:Ameloblasts / Q000378:metabolism / Q000473:pathology; D000567:Amelogenesis Imperfecta / Q000378:metabolism / Q000473:pathology; D053523:Amelogenin / Q000378:metabolism; D000818:Animals; D003743:Dental Enamel / Q000002:abnormalities / Q000378:metabolism; D003746:Dental Enamel Proteins / Q000235:genetics*; D003782:Dental Pulp / Q000002:abnormalities / Q000378:metabolism; D003804:Dentin / Q000002:abnormalities / Q000378:metabolism; D006720:Homozygote; D051379:Mice; D018345:Mice, Knockout; D008963:Molar / Q000002:abnormalities / Q000378:metabolism; D009804:Odontoblasts / Q000378:metabolism / Q000473:pathology; D014083:Tooth Germ / Q000002:abnormalities* / Q000378:metabolism
D053523:Amelogenin; D003746:Dental Enamel Proteins; C038456:tuftelin