Shyamala V, Moulthrop T H, Stratton-Thomas J, Tekamp-Olson P
Department of Molecular Biology, Chiron Corporation, Emeryville, CA 94608.
Cell Mol Biol Res. 1994;40(4):285-96.
A novel variant of endothelin B receptor (ETB) has been found in human brain, placenta, lung, and heart by reverse transcriptase polymerase chain reaction. This variant ETB1 has an additional 30 nucleotide sequence with splice sites at both ends. This results in a 10 amino acid increase in the length of the second cytoplasmic domain of ETB. Polymerase chain reaction on genomic DNA indicates that this sequence is part of the 134 bp intron which separates the second and third exons and is contiguous with the third exon of the ETB gene. Southern blot analysis of chromosomal DNA and genomic PCR results indicate that ETB1 arises by alternative RNA splicing of the single copy ETB gene. The insert sequence in ETB1 gene is absent in bovine, rat, and porcine DNA, and is unique to human DNA. Both ETB and ETB1 have been expressed in heterologous systems to examine their ligand binding and functional properties. Reverse transcriptase polymerase chain reaction of RNA from ETB1 expressing cells indicates that the additional sequence is stably expressed.
通过逆转录聚合酶链反应，在人类大脑、胎盘、肺和心脏中发现了一种新型内皮素B受体（ETB）变体。这种变体ETB1有一个额外的30个核苷酸序列，两端均有剪接位点。这导致ETB第二个细胞质结构域的长度增加了10个氨基酸。对基因组DNA进行的聚合酶链反应表明，该序列是分隔第二和第三外显子的134 bp内含子的一部分，并且与ETB基因的第三外显子相邻。染色体DNA的Southern印迹分析和基因组PCR结果表明，ETB1是由单拷贝ETB基因的可变RNA剪接产生的。ETB1基因中的插入序列在牛、大鼠和猪的DNA中不存在，是人类DNA所特有的。ETB和ETB1均已在异源系统中表达，以检测它们的配体结合和功能特性。对来自表达ETB1的细胞的RNA进行逆转录聚合酶链反应表明，该额外序列能够稳定表达。
