大鼠Na⁺-HCO₃⁻协同转运蛋白的克隆、肾脏分布及调控

Cloning, renal distribution, and regulation of the rat Na+-HCO3- cotransporter.

作者信息

Burnham C E, Flagella M, Wang Z, Amlal H, Shull G E, Soleimani M

机构信息

Department of Medicine, University of Cincinnati School of Medicine, Cincinnati, Ohio 45267-0585, USA.

出版信息

Am J Physiol. 1998 Jun;274(6):F1119-26. doi: 10.1152/ajprenal.1998.274.6.F1119.

DOI:10.1152/ajprenal.1998.274.6.F1119

PMID:9841505

Abstract

We recently reported the cloning and expression of a human kidney Na+-HCO3- cotransporter (NBC-1) (C. E. Burnham, H. Amlal, Z. Wang, G. E. Shull, and M. Soleimani. J. Biol. Chem. 272: 19111-19114, 1997). To expedite in vivo experimentation, we now report the cDNA sequence of rat kidney NBC-1. In addition, we describe both the organ and nephron segment distributions and the regulation of NBC-1 mRNA under three models of pH stress: chloride-depletion alkalosis (CDA), metabolic acidosis, and bicarbonate loading. Rat NBC-1 cDNA encodes an open reading frame of 1,035 amino acids, with 96 and 87% identity to human and salamander NBC-1, respectively. Rat NBC-1 mRNA is expressed at high levels in kidney and brain, with lower levels in colon, stomach, and heart. None appears in liver. In the kidney, NBC-1 is expressed mainly in the proximal tubule, with traces found in medullary thick ascending limb and papilla. HCO3- loading decreased NBC-1 mRNA levels, which were unchanged either by metabolic acidosis or by CDA.

摘要

我们最近报道了人肾钠-碳酸氢根协同转运蛋白（NBC-1）的克隆与表达（C.E. 伯纳姆、H. 阿姆拉尔、Z. 王、G.E. 舒尔和M. 索莱马尼。《生物化学杂志》272: 19111 - 19114，1997年）。为加快体内实验进程，我们现在报道大鼠肾NBC-1的cDNA序列。此外，我们描述了在三种pH应激模型下NBC-1 mRNA的器官和肾单位节段分布以及调控情况：氯缺失性碱中毒（CDA）、代谢性酸中毒和碳酸氢根负荷。大鼠NBC-1 cDNA编码一个由1035个氨基酸组成的开放阅读框，与人及蝾螈NBC-1的同源性分别为96%和87%。大鼠NBC-1 mRNA在肾和脑中高水平表达，在结肠、胃和心脏中表达水平较低。在肝脏中未检测到表达。在肾脏中，NBC-1主要在近端小管表达，在髓袢升支粗段和乳头中有微量表达。碳酸氢根负荷降低了NBC-1 mRNA水平，而代谢性酸中毒或CDA对其无影响。