Antisense inhibition of AMEL translation demonstrates supramolecular controls for enamel HAP crystal growth during embryonic mouse molar development.
During tooth development, enamel organ epithelial cells express a tissue-specific gene product (amelogenin) which presumably functions to control calcium hydroxyapatite crystal growth patterns during enamel biomineralization. The present studies were designed to test the hypothesis that amelogenin as a supramolecular aggregate regulates crystal growth during enamel biomineralization. Antisense oligodeoxynucleotide strategy was used in a simple organ culture system to inhibit amelogenin translation. Under these experimental conditions, antisense treatment prior to and during amelogenin expression resulted in inhibition of amelogenin translation products within immunoprecipitated [35S]methionine metabolically labeled proteins. To determine the efficiency of antisense treatment in this model system, digoxigenin-labeled oligodeoxynucleotides were observed to diffuse throughout the tooth explants including the target ameloblast cells within 24 hours. Ultrastructural analyses of amelogenin supramolecular assembly as electron-dense stippled materials in antisense treated cultures demonstrated dysmorphology of the extracellular enamel matrix with a significant reduction in crystal length and width. We conclude that secreted extracellular proteins form a supramolecular aggregate, which controls both the orientation and dimensions of enamel crystal formation during tooth development.
Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles 90033.
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T
Diekwisch
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David
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P
Bringas
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V
Santos
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HC
Slavkin
D000566:Amelogenesis / Q000235:genetics*; D053523:Amelogenin; D000818:Animals; D016375:Antisense Elements (Genetics); D003460:Crystallization; D003743:Dental Enamel / Q000648:ultrastructure; D003746:Dental Enamel Proteins / Q000235:genetics*; D017886:Durapatite; D006882:Hydroxyapatites; D051379:Mice; D008815:Mice, Inbred Strains; D008854:Microscopy, Electron; D008963:Molar; D009924:Organ Culture Techniques; D014083:Tooth Germ / Q000648:ultrastructure
D053523:Amelogenin; C507200:Amelx protein, mouse; D016375:Antisense Elements (Genetics); D003746:Dental Enamel Proteins; D006882:Hydroxyapatites; D017886:Durapatite