Fliegel L, Dyck J R, Wang H, Fong C, Haworth R S
Department of Biochemistry, Faculty of Medicine, University of Alberta, Edmonton, Canada.
Mol Cell Biochem. 1993 Aug 25;125(2):137-43. doi: 10.1007/BF00936442.
The Na+/H+ exchanger is an integral membrane protein that is universally distribute in mammalian tissues and is responsible for intracellular pH regulation. Several isoforms of the Na+/H+ exchanger exist (NHE-1-NHE-4). The first that was cloned is the amiloride sensitive isoform (NHE-1). Using a fragment of the rabbit cardiac Na+/H+ exchanger cDNA clone we isolated and sequenced Na+/H+ exchanger cDNA from a human heart coding for the complete human Na+/H+ exchanger (NHE-1 isoform). Two overlapping cDNA clones were obtained, giving a combined sequence that contained both 3' and 5' untranslated regions. The 5' and 3' untranslated regions proved to be highly homologous to human sequences described earlier but contained some variations that could affect the mRNA stability and/or the efficiency of translation of the Na+/H+ exchanger. Northern blot analysis and reverse transcriptase polymerase chain reaction confirmed the presence of the 5 kb NHE-1 message in primary cultures of isolated myocytes.
钠氢交换体是一种整合膜蛋白，广泛分布于哺乳动物组织中，负责细胞内pH值的调节。钠氢交换体存在多种亚型（NHE-1 - NHE-4）。第一个被克隆的是对氨氯地平敏感的亚型（NHE-1）。我们利用兔心脏钠氢交换体cDNA克隆片段，从人心脏中分离并测序了编码完整人钠氢交换体（NHE-1亚型）的钠氢交换体cDNA。获得了两个重叠的cDNA克隆，其组合序列包含3'和5'非翻译区。结果证明，5'和3'非翻译区与先前描述的人类序列高度同源，但包含一些可能影响钠氢交换体mRNA稳定性和/或翻译效率的变异。Northern印迹分析和逆转录聚合酶链反应证实，在分离的心肌细胞原代培养物中存在5 kb的NHE-1信使RNA。
