Miller R T, Counillon L, Pages G, Lifton R P, Sardet C, Pouysségur J
Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas 75235-8856.
J Biol Chem. 1991 Jun 15;266(17):10813-9.
The amiloride-sensitive, growth factor-activatable Na/H exchanger (NHE-1) is a ubiquitous mammalian protein that is involved in the regulation of intracellular pH and cell volume. We have determined the intron/exon boundaries and the transcription initiation sites and have characterized a portion of the 5'-flanking regulatory region of the human NHE-1 gene. The Na/H exchanger gene spans approximately 70 kilobases. The coding region is divided into 12 exons and 11 introns, one of which is 41.5 kilobases in length. The first exon contains the entire 5'-noncoding region, which is 786 bases long, and 352 bases of the coding sequence. Primer extension identified two discrete start sites for RNA polymerase. 1377 bases of the 5'-regulatory region were sequenced. The promoter/enhancer region is characterized by a TATA box, four GC boxes, two CAAT boxes, five CACCC boxes, three Ap-1 sites, a cyclic AMP response element, and four partial glucocorticoid response elements. Promoter activities of a 313- and a 1441-base pair fragment containing the TATA box were demonstrated by their ability to direct chloramphenicol acetyltransferase expression when transiently expressed in fibroblasts.
氨氯地平敏感的、生长因子可激活的钠/氢交换体（NHE-1）是一种普遍存在于哺乳动物中的蛋白质，参与细胞内pH值和细胞体积的调节。我们已经确定了内含子/外显子边界和转录起始位点，并对人NHE-1基因5'-侧翼调控区的一部分进行了特征分析。钠/氢交换体基因跨度约70千碱基。编码区分为12个外显子和11个内含子，其中一个内含子长度为41.5千碱基。第一个外显子包含整个5'-非编码区，其长度为786个碱基，以及352个碱基的编码序列。引物延伸确定了RNA聚合酶的两个离散起始位点。对5'-调控区的1377个碱基进行了测序。启动子/增强子区域的特征是有一个TATA盒、四个GC盒、两个CAAT盒、五个CACCC盒、三个Ap-1位点、一个环磷酸腺苷反应元件和四个部分糖皮质激素反应元件。当在成纤维细胞中瞬时表达时，包含TATA盒的313和1441碱基对片段能够指导氯霉素乙酰转移酶的表达，从而证明了它们的启动子活性。
