Tsutsumi M, Liang G, Jones P A
Department of Biochemistry and Molecular Biology, Urologic Cancer Research Laboratory USC/Norris Comprehensive Cancer Center, University of Southern California, School of Medicine, Los Angeles, CA 90033, USA.
Gene. 1999 Mar 4;228(1-2):43-9. doi: 10.1016/s0378-1119(99)00014-1.
Using RT-PCR and rapid amplification of 5' cDNA ends (5' RACE), we have cloned three previously unrecognized endothelin B receptor (EDNRB) transcripts from a human melanoma cell line. Three distinct types of cDNAs (EDNRBDelta1, Delta2 and Delta3) were identified. EDNRBDelta1 starts upstream of the published transcription start site of hEDNRB without splicing, whereas, EDNRBDelta2 and EDNRBDelta3 are alternatively spliced. EDNRBDelta1 and EDNRBDelta2 share the same transcription initiation site and are 560bp upstream of the conventional hEDNRB, whereas that of EDNRBDelta3 is 939bp upstream from that described for the conventional hEDNRB. Interestingly, many transcription factor motifs are detectable in the upstream regions of these transcription initiation sites. The predicted amino acid sequences reveal that EDNRBDelta1 and EDNRBDelta2 produce the same protein as the conventional hEDNRB, but EDNRBDelta3 would give rise to additional in-frame 89- or 83-amino-acid residues at the N-terminus. EDNRBDelta3 generates the same amino acid sequence at the C terminus, but utilizes the polyadenylation signal within the open reading frame, resulting in a shorter 3'UTR. These transcripts are widely expressed in human tissues, but their expression patterns vary between different tissues.
利用逆转录聚合酶链反应（RT-PCR）和5' cDNA末端快速扩增技术（5' RACE），我们从一株人黑色素瘤细胞系中克隆出了三种先前未被识别的内皮素B受体（EDNRB）转录本。鉴定出了三种不同类型的cDNA（EDNRBDelta1、Delta2和Delta3）。EDNRBDelta1起始于已发表的hEDNRB转录起始位点上游且无剪接，而EDNRBDelta2和EDNRBDelta3是选择性剪接。EDNRBDelta1和EDNRBDelta2共享相同的转录起始位点，且位于传统hEDNRB上游560bp处，而EDNRBDelta3的转录起始位点比传统hEDNRB所述的上游939bp。有趣的是，在这些转录起始位点的上游区域可检测到许多转录因子基序。预测的氨基酸序列显示，EDNRBDelta1和EDNRBDelta2产生的蛋白质与传统hEDNRB相同，但EDNRBDelta3在N端会额外产生89个或83个符合读框的氨基酸残基。EDNRBDelta3在C端产生相同的氨基酸序列，但利用开放阅读框内的聚腺苷酸化信号，导致3'非翻译区（3'UTR）较短。这些转录本在人体组织中广泛表达，但其表达模式在不同组织之间有所不同。
