Ban J, Eckhart L, Weninger W, Mildner M, Tschachler E
Department of Dermatology, University Vienna Medical School, Austria.
Biochem Biophys Res Commun. 1998 Jul 9;248(1):147-52. doi: 10.1006/bbrc.1998.8907.
Alternative splicing has been shown to generate two isoforms of the apoptosis regulator bcl-x, Bcl-xL and Bcl-xS, in humans. Here we describe the identification and characterization of a third splice variant of the human bcl-x gene. It differs from previously described bcl-x transcripts in two respects: (1) a novel facultative intron is spliced out at the 5' untranslated region and (2) the open reading frame arises from a continuous genomic sequence extending over the splice donor sites utilized by the bcl-xL and bcl-xS transcripts. Since the resulting molecule has an organisation homologous to mouse and rat Bcl-x beta we suggest calling this novel protein human Bcl-x beta. Northern blot analysis revealed that bcl-x beta mRNA is expressed in numerous cell lines. Like Bcl-xL, h-Bcl-x binds to the pro-apoptotic protein Bax, suggesting a functional activity in vivo.
在人类中，可变剪接已被证明可产生凋亡调节因子bcl-x的两种异构体，即Bcl-xL和Bcl-xS。在此，我们描述了人类bcl-x基因第三种剪接变体的鉴定和特征。它在两个方面与先前描述的bcl-x转录本不同：（1）一个新的选择性内含子在5'非翻译区被剪接出去；（2）开放阅读框源自延伸至bcl-xL和bcl-xS转录本所利用的剪接供体位点的连续基因组序列。由于产生的分子具有与小鼠和大鼠Bcl-xβ同源的结构，我们建议将这种新蛋白质称为人类Bcl-xβ。Northern印迹分析显示，bcl-xβ mRNA在众多细胞系中表达。与Bcl-xL一样，h-Bcl-x与促凋亡蛋白Bax结合，表明其在体内具有功能活性。
