Ciliberto G, Dente L, Cortese R
Cell. 1985 Jun;41(2):531-40. doi: 10.1016/s0092-8674(85)80026-x.
We have cloned the human alpha 1-antitrypsin (alpha 1-AT) gene and identified the promoter and the transcription initiation point. The cloned gene, following transfection, is expressed in a cell-specific manner, being transcribed in a human hepatoma cell line (Hep3B) but not in HeLa cells. We show that the 5' flanking region of the alpha 1-AT gene contains DNA sequences sufficient for efficient transcription in Hep3B but not in HeLa cells. This DNA sequence also activates, in a cell-specific manner, heterologous promoters such as that of SV40; however, the effect is only obtained in one orientation, suggesting that this cis-acting cell-specific element does not share all the features generally associated with enhancers. By cotransfection-competition experiments we also show the existence of a limiting trans-acting factor, essential for the expression of the alpha 1-AT gene in Hep3B cells.
我们克隆了人类α1-抗胰蛋白酶（α1-AT）基因，并确定了启动子和转录起始点。克隆的基因在转染后以细胞特异性方式表达，在人肝癌细胞系（Hep3B）中可转录，但在HeLa细胞中则不能。我们发现α1-AT基因的5'侧翼区域包含足以在Hep3B细胞中高效转录但在HeLa细胞中不行的DNA序列。该DNA序列还以细胞特异性方式激活异源启动子，如SV40的启动子；然而，这种效应仅在一个方向上获得，这表明这种顺式作用细胞特异性元件并不具备通常与增强子相关的所有特征。通过共转染竞争实验，我们还证明了存在一种限制性反式作用因子，它对α1-AT基因在Hep3B细胞中的表达至关重要。
