INITIAL ENAMEL CRYSTALS ARE NOT SPATIALLY ASSOCIATED WITH MINERALIZED DENTIN
INITIAL ENAMEL CRYSTALS ARE NOT SPATIALLY ASSOCIATED WITH MINERALIZED DENTIN
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DOI：
10.1007/bf00300701
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发表时间：
1995-01-01
影响因子：
3.6
通讯作者：
SLAVKIN, HC
中科院分区：
文献类型：
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作者：
DIEKWISCH, TGH;BERMAN, BJ;SLAVKIN, HC
在哺乳动物牙齿发育相关的上皮-间质相互作用过程中，上皮来源和间质来源的细胞外基质分子形成了一个离散的牙本质-牙釉质交界处。形成这种连接所需的发育和分子过程尚不清楚。为了解决这个问题，我们设计了研究来验证外胚层来源的上皮细胞合成和分泌珐琅质蛋白的假设，这些蛋白具有成核和调节珐琅质磷酸钙晶体生长的功能。最初发现的牙釉质晶体与邻近的牙本质是分离的。电子探针分析显示，早期的牙釉质晶体是八磷酸钙或三磷酸钙，而不是羟基磷灰石。此后，牙釉质晶体与相邻的羟基磷灰石晶体融合，尽管与矿化的牙本质相关的羟基磷灰石晶体明显较小。因此，我们解释我们的数据表明，新生牙釉质晶体成核和生长与远端牙本质特征的矿化过程无关。我们进一步认为，牙釉质蛋白的基因表达似乎在早期牙釉质形成过程中具有组成功能，并且釉质原蛋白和牙釉质的超分子聚集体为初始牙釉质基质的成核和晶体生长提供了微环境。
During epithelial-mesenchymal interactions associated with mammalian tooth development, epithelially-derived and mesenchymally-derived extracellular matrix molecules form a discrete dentine-enamel junction. The developmental and molecular processes required to form this junction are not known. To address this problem we designed studies to test the hypothesis that ectodermally-derived epithelial cells synthesize and secrete enamel proteins which function to nucleate and regulate the growth of enamel calcium phosphate crystals. Initial enamel crystals were detected separate from the adjacent dentine. Electron-microprobe analyses revealed that early enamel crystals were octacalciumphosphate or tricalciumphosphate rather than hydroxyapatite, Thereafter, enamel crystals became confluent with the adjacent, albeit significantly smaller hydroxyapatite crystals associated with mineralized dentine. Therefore, we interpret our data to indicate that de novo enamel crystal nucleation and growth are independent from the mineralization processes characterized far dentine. We further argue that gene expression of enamel protein appears to have a constitutive function during early enamel formation and that supramolecular aggregates of amelogenin and enamelin provide the microenvironment for the nucleation and crystal growth of the initial enamel matrix.