Wurtz T, Lundmark C, Christersson C, Bawden J W, Slaby I, Hammarström L
Karolinska Institute, Center for Oral Biology, Huddinge, Sweden.
J Bone Miner Res. 1996 Jan;11(1):125-31. doi: 10.1002/jbmr.5650110117.
The expression of amelogenin mRNA in growing rat molars was studied. Northern blotting and the analysis of cDNA isolates revealed two predoninant variants. One group of cDNA inserts contained sequences of a long mRNA version and the other group contained mRNA sequences of the shorter leucin-rich amelogenin polypeptide (LRAP). The LRAP group was deficient in an internal stretch which coded for a peptide with a high potential for beta turns. Northern blot experiments showed that most amelogenin RNA in rat teeth was represented by two bands of 1.1 and 0.8 kb. Two oligonucleotide probes were designed that were specific for the long version and for the LRAP variant. The probes were used for in situ hybridization experiments on sections of developing maxillar teeth of rats between day 2 and day 15 after birth. Both RNA species were accumulated concomitantly and exclusively in cells of the inner enamel epithelium. Expression was first observed at the mesial cusp sides and finally involved the whole ameloblast layer except for the cells adjacent to the enamel-free region at the tip of the cusps. The early amelogenin RNA expression occurred adjacent to the initial deposition of the dentin matrix. Low amounts of amelogenin RNA persisted after the differentiation of ameloblasts into the maturative stage. The sequence of events was similar in all three molars.
对生长中的大鼠磨牙中釉原蛋白mRNA的表达进行了研究。Northern印迹法和cDNA分离物分析揭示了两种主要变体。一组cDNA插入片段包含长mRNA版本的序列，另一组包含较短的富含亮氨酸的釉原蛋白多肽（LRAP）的mRNA序列。LRAP组在编码具有高β转角潜力的肽的内部片段中存在缺陷。Northern印迹实验表明，大鼠牙齿中的大多数釉原蛋白RNA由1.1 kb和0.8 kb的两条带代表。设计了两种寡核苷酸探针，分别对长版本和LRAP变体具有特异性。这些探针用于对出生后第2天至第15天的大鼠上颌发育牙齿切片进行原位杂交实验。两种RNA种类同时且仅在内釉上皮细胞中积累。表达首先在近中尖侧观察到，最终除了尖部无釉质区域相邻的细胞外，整个成釉细胞层都有表达。早期釉原蛋白RNA表达发生在牙本质基质初始沉积附近。成釉细胞分化为成熟阶段后，仍有少量釉原蛋白RNA持续存在。所有三颗磨牙中的事件顺序相似。
