Haendler B, Hechler U, Schleuning W D
Institute of Cellular and Molecular Biology, Schering AG, Berlin, Germany.
J Cardiovasc Pharmacol. 1992;20 Suppl 12:S1-4. doi: 10.1097/00005344-199204002-00002.
Complementary DNAs coding for two different endothelin (ET) receptors were isolated from a human lung cDNA library. DNA sequencing revealed that they corresponded to either the ET-1-selective receptor subtype originally identified in cows (ETA) or the nonselective subtype first found in rats (ETB). An open reading frame coding for a 427 (ETA) or a 442 (ETB) amino acid-long protein, with a transmembrane topology also found in other G protein-coupled receptors, was determined. Whereas the amino acid identity is about 90% between the characterized members of a given receptor subtype, with the best conserved parts being the hydrophobic transmembrane domains, less than 60% identity was found between the human A and B subtypes. Southern blot analysis of human genomic DNA revealed the existence of multiple hybridizing bands when using probes derived from the full-length ETA or ETB cDNAs. However, when shorter fragments were selected as probes, only one band remained detectable, which suggests the existence of a single-copy gene for each subtype of ET receptor.
从人肺cDNA文库中分离出编码两种不同内皮素（ET）受体的互补DNA。DNA测序显示，它们分别对应于最初在牛中鉴定出的ET-1选择性受体亚型（ETA）或最初在大鼠中发现的非选择性亚型（ETB）。确定了一个编码427个氨基酸（ETA）或442个氨基酸（ETB）的开放阅读框，其跨膜拓扑结构也存在于其他G蛋白偶联受体中。虽然给定受体亚型的特征成员之间的氨基酸同一性约为90%，其中保守性最好的部分是疏水跨膜结构域，但人A和B亚型之间的同一性不到60%。用人基因组DNA进行的Southern印迹分析显示，当使用源自全长ETA或ETB cDNA的探针时，存在多个杂交带。然而，当选择较短的片段作为探针时，只能检测到一条带，这表明每种ET受体亚型都存在单拷贝基因。
