Matrix Gla protein inhibition of tooth mineralization.
Extracellular matrix (ECM) mineralization is regulated by mineral ion availability, proteins, and other molecular determinants. To investigate protein regulation of mineralization in tooth dentin and cementum, and in alveolar bone, we expressed matrix Gla protein (MGP) ectopically in bones and teeth in mice, using an osteoblast/odontoblast-specific 2.3-kb Col1a1 promoter. Mandibles were analyzed by radiography, micro-computed tomography, light microscopy, histomorphometry, and transmission electron microscopy. While bone and tooth ECMs were established in the Col1a1-Mgp mice, extensive hypomineralization was observed, with values of unmineralized ECM from four- to eight-fold higher in dentin and alveolar bone when compared with that in wild-type tissues. Mineralization was virtually absent in tooth root dentin and cellular cementum, while crown dentin showed "breakthrough" areas of mineralization. Acellular cementum was lacking in Col1a1-Mgp teeth, and unmineralized osteodentin formed within the pulp. These results strengthen the view that bone and tooth mineralization is critically regulated by mineralization inhibitors.
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Faculty of Dentistry, McGill University, 3640 University Street, Montreal, QC, Canada H3A 2B2.
Murshed
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McKee
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D000539:Alveolar Process / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D003739:Dental Cementum / Q000378:metabolism / Q000648:ultrastructure; D003804:Dentin / Q000378:metabolism / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000378:metabolism* / Q000648:ultrastructure; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D008334:Mandible; D051379:Mice; D008822:Mice, Transgenic; D014074:Tooth Calcification / Q000235:genetics / Q000502:physiology*; D000097568:Matrix Gla Protein
D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; D000097568:Matrix Gla Protein