Ameloblastin is a cell adhesion molecule required for maintaining the differentiation state of ameloblasts
نویسندگان
چکیده
Tooth morphogenesis results from reciprocal interactions between oral epithelium and ectomesenchyme culminating in the formation of mineralized tissues, enamel, and dentin. During this process, epithelial cells differentiate into enamel-secreting ameloblasts. Ameloblastin, an enamel matrix protein, is expressed by differentiating ameloblasts. Here, we report the creation of ameloblastin-null mice, which developed severe enamel hypoplasia. In mutant tooth, the dental epithelium differentiated into enamel-secreting ameloblasts, but the cells were detached from the matrix and subsequently lost cell polarity, resumed proliferation, and formed multicell layers. Expression of Msx2, p27, and p75 were deregulated in mutant ameloblasts, the phenotypes of which were reversed to undifferentiated epithelium. We found that recombinant ameloblastin adhered specifically to ameloblasts and inhibited cell proliferation. The mutant mice developed an odontogenic tumor of dental epithelium origin. Thus, ameloblastin is a cell adhesion molecule essential for amelogenesis, and it plays a role in maintaining the differentiation state of secretory stage ameloblasts by binding to ameloblasts and inhibiting proliferation.
منابع مشابه
Effect of BMP-2 on Gene Expression of Enamel Matrix Proteins at the Dental Epithelial Cell Line
Epithelial-mesenchymal interactions play an important role in the control of ameloblasts and odentoblasts differentiation, and the bone morphogenetic proteins (BMPs) are known factors that regulate the differentiation of ameloblasts. We examined the effect of BMP-2 on the expression of the enamel matrix protein genes at the dental epithelial cell line. BMP-2 induced a 3to 4-fold increase in ame...
متن کاملAnalysis of co-assembly and co-localization of ameloblastin and amelogenin
Epithelially-derived ameloblasts secrete extracellular matrix proteins including amelogenin, enamelin, and ameloblastin. Complex intermolecular interactions among these proteins are believed to be important in controlling enamel formation. Here we provide in vitro and in vivo evidence of co-assembly and co-localization of ameloblastin with amelogenin using both biophysical and immunohistochemic...
متن کاملEpithelial-specific knockout of the Rac1 gene leads to enamel defects.
The Ras-related C3 botulinum toxin substrate 1 (Rac1) gene encodes a 21-kDa GTP-binding protein belonging to the RAS superfamily. RAS members play important roles in controlling focal adhesion complex formation and cytoskeleton contraction, activities with consequences for cell growth, adhesion, migration, and differentiation. To examine the role(s) played by RAC1 protein in cell-matrix interac...
متن کاملRab11 is required for maintenance of cell shape via βPS integrin mediated cell adhesion in Drosophila
In eukaryotes, vesicle trafficking is regulated by the small monomeric GTPases of the Rab protein family. Rab11, (a subfamily of the Ypt/Rab gene family) an evolutionarily conserved, ubiquitously expressed subfamily of small monomeric Rab GTPases, has been implicated in regulating vesicular trafficking through the recycling of endosomal compartment. In an earlier communication, we have shown th...
متن کاملP9-reduced expression of tight junction proteins ZO-1 and Claudin-1 in ameloblasts and odontoblasts of Epiprofin/Sp6 deficient mice.
Introduction Odontoblasts and ameloblasts are columnar cells that characterize by a highly polarized distribution of organelles. Junctional complexes and the cytoskeleton are important in maintaining ameloblast and odontoblast cell polarity and cell-cell interactions. In addition, cell adhesion is a key regulator of gene expression and cell differentiation. Tight junction binding proteins prote...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The Journal of Cell Biology
دوره 167 شماره
صفحات -
تاریخ انتشار 2004