Molecular diversity and interaction of the enamel protein in the odontogenesis.

釉蛋白，如釉原蛋白和鞘蛋白，具有通过mRNA的选择性剪接产生的几种同种型。为了阐明牙胚发育中分子差异的作用及其相互作用，我们开发了识别特定分子形式的区域特异性抗体。采用免疫组织化学和免疫组织化学方法对小鼠牙胚和大鼠切牙的釉质器官和未成熟釉质基质进行了分析。结果如下：1.小鼠牙胚分化成釉细胞表达低分子量鞘蛋白2.大鼠切牙生长端除表达55 kDa和65 kDa鞘蛋白外，还表达33 kDa和36 kDa鞘蛋白，除65 kDa蛋白外，其余蛋白在用Brefeldin A处理后均增加。3.分化中的成牙本质细胞面对内釉上皮、分化早期的成釉细胞和年轻成牙本质细胞附近的成纤维细胞样细胞用C-末端特异性鞘蛋白抗体染色，但不用N-末端特异性鞘蛋白抗体染色，提示这些细胞可能表达33 kDa和36 kDa的鞘蛋白。4.分化成釉细胞的基膜完整，表达鞘蛋白。

Enamel proteins, such as amelogenins and sheath proteins, have several isoforms produced by alternative splicing of mRNAs. In order to clarify the role of molecular diversities and their interactions in the development of the tooth germ, we have developed region specific antibodies which recognize specific molecular forms. Enamel organ and immature enamel matrix from the tooth germs of the mouse and incisors of the rat were analyzed by means of immunochemistry and immunohistochemistry. The results are summarized as follows.1.Differentiating ameloblasts of the developing murine tooth germ expressed low molecular weight sheath protein (near 35kDa) in the early stage, while those in the late differentiation stage and the secretory ameloblast expressed 55kDa and 65kDa sheath proteins.2.Growing end or the rat incisor expressed 33 kDa and 36 kDa sheath protein besides 55 kDa and 65 kDa ones, all of which except for 65 kDa protein increased after the treatment of the rat with Brefeldin A.3.Differentiating odontoblast facing inner enamel epithelium, early stage of differentiating ameloblast, and fibroblast like cells near the young odontoblast were stained with C-terminal specific sheath protein antibody but not with N terminal specific one, suggesting that these cell might express 33kDa and 36kDa sheath protein.4.Differentiating ameloblasts with intact basal lamina expressed sheath protein.