Snead M L, Lau E C, Fincham A G, Zeichner-David M, Davis C, Slavkin H C
School of Dentistry, University of Southern California, Los Angeles 90089-0191.
Connect Tissue Res. 1989;22(1-4):101-9.
Mammalian enamel matrix is composed of two principal proteins, the enamelins and amelogenin. Recombinant complementary DNA (cDNA) molecules for the predominant mouse amelogenin have been identified, characterized by direct determination of the DNA sequence, and used as a specific hybridization probe. The spatial- and temporal-restricted pattern for amelogenin gene expression within developing mouse molars has been traced at the level of a single cell using in situ hybridization. The mouse genome has been shown to contain only one copy of the amelogenin (AMEL) gene which is not amplified or rearranged during ameloblast determination. In contrast, the human genome contains two copies of the AMEL gene, one residing on the X chromosome and one upon the Y chromosome. These observations, the availability of specific enamel gene probes coupled with the application of new techniques in molecular biology now afford unique opportunities for the analysis of the molecular basis of inherited defects of human enamel such as amelogenesis imperfecta. Recent advances towards obtaining a physical map and the complete nucleotide sequence for the human genome, as well as the documented developmental biology, defined genetics and transgenic capability of the mouse, suggest that mouse and man are the most relevant and potentially informative models for analysis of normal and abnormal enamel biomineralization.
哺乳动物的牙釉质基质由两种主要蛋白质组成，即釉原蛋白和釉蛋白。已鉴定出小鼠主要釉原蛋白的重组互补DNA（cDNA）分子，通过直接测定DNA序列对其进行了表征，并将其用作特异性杂交探针。利用原位杂交技术，在单细胞水平上追踪了发育中小鼠磨牙内釉原蛋白基因表达的时空受限模式。已证明小鼠基因组仅包含一个釉原蛋白（AMEL）基因拷贝，该基因在成釉细胞形成过程中不会扩增或重排。相比之下，人类基因组包含两个AMEL基因拷贝，一个位于X染色体上，一个位于Y染色体上。这些观察结果，加上特异性牙釉质基因探针的可用性以及分子生物学新技术的应用，现在为分析人类牙釉质遗传性缺陷（如牙釉质发育不全）的分子基础提供了独特的机会。在获取人类基因组的物理图谱和完整核苷酸序列方面的最新进展，以及已记录的小鼠发育生物学、明确的遗传学和转基因能力，表明小鼠和人类是分析正常和异常牙釉质生物矿化最相关且可能提供信息的模型。
