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.
Diekwisch
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Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California, Los Angeles 90033.
David
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Bringas
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Santos
V
V
Slavkin
H C
HC
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