The overall objective of this proposal is to understand the function of enamel gene products (i.e., amelogenins, enamelins and enamel proteinases), to advance the understanding of the process of amelogenesis, to create a strategy to produce an enamel bioceramic as a novel dental restorative biomaterial, and to improve the diagnosis of the various types of amelogenesis imperfecta. We hypothesize the motifs within the anionic enamelin protein (e.g.tuftelin) structure serve to nucleate the initial crystalline phase, and that motifs within amelogenin protein aggregates regulate the size, orientation and patterns of the growing enamel crystals. We further predict that proteases (e.g. calcium-dependent metalloproteinases) degrade proteins and facilitate the removal of water and protein from the mineralizing extracellular matrix. To address this hypothesis, the following Specific Aims have been formulated: (1) To determine the function of amelogenins and enamelins during mouse amelogenesis in in vitro ameloblast cell culture, in transfected odontoblast cell cultures and mouse molar tooth organ culture systems using antisense inhibition strategies. (2) To determine the function of enamelins to nucleate octacalcium phosphate (OCP) or hydroxyapatite (HAP) in vitro. Recombinant enamelins will be evaluated as nucleators for OCP or HAP in vitro. (3) To determine the function of amelogenins to regulate the size and patterns of OCP or HAP crystal growth in vitro. Recombinant amelogenins will be evaluated as regulators for the crystal growth and patterns of growth in vitro. Subsequent protein engineering approaches using site-directed mutagenesis will enable the identification of the motifs required for OCP or HAP crystal growth along the c-axis as well as the patterns of crystal growth. (4) To determine the function of enamel proteases to regulate both structural properties and the stepwise removal of enamel proteins and subsequently to regulate crystal formation. We propose to isolate and characterize the enamel protease gene product. (5) To fabricate enamel HAP crystal formation in vitro. Enamel replacement therapy is a strategy to use recombinant enamel protein motifs to fabricate an enamel bioceramic as a possible dental enamel restorative biomaterial. These experiments are a logical extension of the proposed functional studies to define how enamel proteins regulate enamel OCP and HAP crystal formation.

Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Fong, Hanson; White, Shane N; Paine, Michael L et al. (2003) Enamel structure properties controlled by engineered proteins in transgenic mice. J Bone Miner Res 18:2052-9
Moradian-Oldak, J (2001) Amelogenins: assembly, processing and control of crystal morphology. Matrix Biol 20:293-305
Wen, H B; Fincham, A G; Moradian-Oldak, J (2001) Progressive accretion of amelogenin molecules during nanospheres assembly revealed by atomic force microscopy. Matrix Biol 20:387-95
Paine, M L; White, S N; Luo, W et al. (2001) Regulated gene expression dictates enamel structure and tooth function. Matrix Biol 20:273-92
Wen, H B; Moradian-Oldak, J; Fincham, A G (2000) Dose-dependent modulation of octacalcium phosphate crystal habit by amelogenins. J Dent Res 79:1902-6
Wen, H B; Moradian-Oldak, J; Zhong, J P et al. (2000) Effects of amelogenin on the transforming surface microstructures of Bioglass in a calcifying solution. J Biomed Mater Res 52:762-73
Moradian-Oldak, J; Paine, M L; Lei, Y P et al. (2000) Self-assembly properties of recombinant engineered amelogenin proteins analyzed by dynamic light scattering and atomic force microscopy. J Struct Biol 131:27-37
Wen, H B; Moradian-Oldak, J; Leung, W et al. (1999) Microstructures of an amelogenin gel matrix. J Struct Biol 126:42-51
Fincham, A G; Moradian-Oldak, J; Simmer, J P (1999) The structural biology of the developing dental enamel matrix. J Struct Biol 126:270-99
Wen, H B; Moradian-Oldak, J; Fincham, A G (1999) Modulation of apatite crystal growth on Bioglass by recombinant amelogenin. Biomaterials 20:1717-25

Showing the most recent 10 out of 82 publications