Cytochemical and molecular biological study for the molecular diversity of the enamel protein

釉质蛋白，如釉原蛋白和鞘蛋白，有几种异构体，由mRNAs的选择性剪接产生。为了阐明釉原蛋白分子多样性在成釉过程中的作用，我们开发了识别特定分子形式的区域特异性抗体。用免疫组织化学和免疫组织化学方法对猪牙胚的釉质器官和未成熟的釉质基质进行了分析。研究结果总结如下：1。对猪乳磨牙牙胚牙胚牙釉质基质形成阶段未成熟牙釉质的免疫化学分析表明，合成多肽抗体染色的蛋白最高相对分子质量分别为18 kDa、6.b kDa和26 kDa。对猪乳磨牙牙胚基质形成阶段的免疫组织化学研究表明，抗体可与含有外显子2-5的釉原蛋白发生强烈的棱柱鞘反应，而与外显子5-6b反应较弱。在分化阶段，外显子2-6b翻译的釉原蛋白的表达晚于其他外显子5-6b和6b的表达。另一方面，在向早期成熟的过渡阶段，从外显子2-5b翻译的釉原蛋白在所检测的釉原蛋白中消失得最晚

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 of amelogenin proteins in amelogenesis, we have developed region specific antibodies which recognize specific molecular forms. Enamel organ and immature enamel matrix from the porcine tooth germ were analyzed by means of immunochemistry and immunohistochemistry. The results are summarized as follows1. Immunochemical analysis of the immature enamel from the matrix formation stage in the porcine deciduous molar tooth germ showed that the highest molecular weights of proteins stained with antibodies raised against synthetic peptide containing amino acid sequences which correspond amelogenin exons 2-5, 5-6b and 4a were 18 kDa, 6.b kDa and 26 kDa, respectively2. Immunohistochemistry of the matrix formation stage of porcine deciduous molar tooth germ showed that antibodies might reacted with amelogenins containing exons 2-5 stained prism sheath intensely and that exons 5-6b less intensely3. At the differentiation stage, expression of amelogenins translated from exons 2-6b were later than other amelogenins, such as those from exons 5-6b and 6b. On the other hand, at the transition to early maturation stage, disappearance of amelogenins translated from exons 2-5b were latest among the amelogenins examined