Non-collagenous proteins in the apical portion of the forming root in porcine permanent incisor tooth germs

以猪恒切牙牙胚为材料，研究釉质蛋白在牙胚形成根端组织中的表达。根据组织化学方法证实，样品含有作为细胞外基质的前牙本质、牙本质和薄骨水泥，并且还含有大量细胞，如成牙本质细胞、牙乳头细胞、成牙骨质细胞、滤泡细胞和碎裂的HERS细胞。用胍法提取时，提取液中含有大量的组子，组子与抗釉蛋白血清发生交叉反应。免疫印迹分析中，使用醋酸溶液是合理的，因为提取物中含有少量的组蛋白。釉原蛋白，釉蛋白和鞘蛋白的免疫印迹分析中检测到，但在少量。釉蛋白的cDNA扩增产物也证实了釉蛋白在APFR中的表达，并可能与破碎的Hertwig上皮根鞘细胞有关。釉原蛋白的表达并不上级釉蛋白和鞘蛋白。这与参与釉基质形成的分泌型成釉细胞的表达模式不同。这些结果表明，在APFR中发现的釉原蛋白没有形成由釉原蛋白胶束构建的三维结构，这是在分泌性釉基质结构上提出的。免疫组化检测显示釉质蛋白衍生物发生了降解。目前尚不清楚与这些降解相关的蛋白酶，因为明胶和酪蛋白酶谱中未检测到釉质基质丝氨酸蛋白酶1和釉质溶解素的活性。因此，釉质蛋白容易扩散，降解进入未来牙骨质的基质中。它们的一些衍生物可能在牙骨质形成中起作用。

Detection and expression of enamel proteins were explored on the tissue sample prepared from the apical portion of forming root (APFR) in porcine permanent incisor tooth germs. It was confirmed according to a histochemical method that the sample contained predentin, dentin and thin cement as extracellular matrices, and also contained a lot of cells as odontoblasts, dental papilla cells, cementoblasts, follicular cells, and fragmentized HERS cells. When a guanidine solution was employed for the extraction, it contained a lot of histons, which were croos-reacted with anti-enamel proteins sera. The employment of acetic acid solution was reasonable for the immunoblot studies, since the extractant contained small amount of histons.Amelogenin, enamelin and sheathlin were detected by immunoblot analyses, but in a small amounts. The expressions of enamel proteins were also proved in the APFR sample with PCR amplification products of their cDNAs, and may be related to the cells of fragmentized Hertwig's epithelial root sheath. The amelogenin was not expressed superior to the enamelin and sheathlin. It was different from the expression pattern of the secretary ameloblasts involved to the enamel matrix formation. These results suggest that the amelogenins found in the APFR do not form the three-dimensional structure constructed by amelogenin micelles, which is proposed on the secretary enamel matrix structure. The immunochemical detections of enamel proteins' derivatives showed the occurrences of their degradation. It is at present unclear about the proteinases related to these degradations, since the activities of enamel matrix serine proteinase 1 and enamelysin were not detected on gelatin and casein zymograms. therefore, the enamel proteins spread easily out with degradation into the matrix of future cementum. Some of their derivatives may play a role in cementum formation.