Salido E C, Yen P H, Koprivnikar K, Yu L C, Shapiro L J
Howard Hughes Medical Institute, University of California School of Medicine, Harbor-UCLA Medical Center, Torrance.
Am J Hum Genet. 1992 Feb;50(2):303-16.
Amelogenins, a family of extracellular matrix proteins of the dental enamel, are transiently but abundantly expressed by ameloblasts during tooth development. Amelogenins seem to regulate the formation of crystallites during the secretory stage of enamel development, while they are specifically degraded during tooth-bud maturation. In this paper we report the characterization of the AMGX and AMGY genes on the short arms of the human X and Y chromosomes which encode the amelogenins. Our studies on the expression of the amelogenin genes in male developing tooth buds showed that both the AMGX and AMGY genes are transcriptionally active and encode potentially functional proteins. We have isolated genomic and cDNA clones from both the AMGX and AMGY loci and have studied the sequence organization of these two genes. Reverse transcriptase (RT)PCR amplification of the 5' portion of the amelogenin transcripts revealed several alternatively spliced products. The splicing pattern observed in the Y-derived mRNA varies from that of the X-derived mRNA. The promoter regions from both genes and the predicted amelogenin protein sequences are presented. This information will be useful for studying the molecular basis of X-linked amelogenesis imperfecta, for understanding the evolution and regulation of gene expression on the mammalian sex chromosomes, and for investigating the role of amelogenin genes during tooth development.
釉原蛋白是牙釉质细胞外基质蛋白家族，在牙齿发育过程中由成釉细胞短暂但大量表达。在釉质发育的分泌阶段，釉原蛋白似乎调节微晶的形成，而在牙胚成熟过程中它们会被特异性降解。在本文中，我们报道了人类X和Y染色体短臂上编码釉原蛋白的AMGX和AMGY基因的特征。我们对雄性发育牙胚中釉原蛋白基因表达的研究表明，AMGX和AMGY基因均具有转录活性，并编码潜在的功能蛋白。我们从AMGX和AMGY基因座分离出基因组和cDNA克隆，并研究了这两个基因的序列组织。对釉原蛋白转录本5'部分的逆转录酶（RT）PCR扩增揭示了几种可变剪接产物。在Y衍生的mRNA中观察到的剪接模式与X衍生的mRNA不同。本文还展示了这两个基因的启动子区域以及预测的釉原蛋白序列。这些信息将有助于研究X连锁型釉质发育不全的分子基础，理解哺乳动物性染色体上基因表达的进化和调控，以及研究釉原蛋白基因在牙齿发育过程中的作用。
