Shimokawa H, Sobel M E, Sasaki M, Termine J D, Young M F
J Biol Chem. 1987 Mar 25;262(9):4042-7.
The amelogenins are a complex mixture of hydrophobic proteins that are the major organic component of developing enamel. To study the molecular mechanisms underlying the heterogeneity of the amelogenins we isolated cDNA clones encoding these proteins. The clones were definitively identified by hybrid-selected translation experiments and by comparison of the DNA sequence with the protein-derived amino acid sequence. Southern hybridization of bovine genomic DNA indicated that amelogenin is a single copy gene. However, Northern hybridization experiments distinctly showed two major species of mRNA, each of which were sufficiently large enough to encode the highest known molecular weight species of amelogenin proteins. Furthermore, immunoprecipitation of hybrid-selected translation products using isolated amelogenin cDNA showed multiple, translated protein products. These data are supportive of a differential mRNA processing mechanism involved in generating a heterogeneous family of amelogenin matrix proteins from a single gene.
釉原蛋白是疏水蛋白的复杂混合物，是发育中釉质的主要有机成分。为了研究釉原蛋白异质性背后的分子机制，我们分离了编码这些蛋白的cDNA克隆。通过杂交选择翻译实验以及将DNA序列与蛋白质衍生的氨基酸序列进行比较，明确鉴定了这些克隆。牛基因组DNA的Southern杂交表明釉原蛋白是单拷贝基因。然而，Northern杂交实验清楚地显示出两种主要的mRNA种类，每种mRNA都足够大，足以编码已知分子量最高的釉原蛋白种类。此外，使用分离的釉原蛋白cDNA对杂交选择的翻译产物进行免疫沉淀显示出多种翻译后的蛋白质产物。这些数据支持了一种差异mRNA加工机制，该机制参与从单个基因产生异质性的釉原蛋白基质蛋白家族。
