Type 1 plasminogen activator inhibitor gene: functional analysis and glucocorticoid regulation of its promoter.
Type 1 plasminogen activator inhibitor gene: functional analysis and glucocorticoid regulation of its promoter.
复制标题
1型纤溶酶原激活剂抑制基因：其启动子的功能分析和糖皮质激素调控。
DOI：
10.1073/pnas.85.15.5525
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发表时间：
1988
影响因子：
11.1
通讯作者：
Loskutoff,DJ
中科院分区：
文献类型：
--
作者：
vanZonneveld,AJ;Curriden,SA;Loskutoff,DJ
纤溶酶原激活物抑制物1是纤溶系统的重要组成部分，其生物合成受到复杂调控。为了在转录水平上研究这种调控，我们对人纤溶酶原激活物抑制物1基因的启动子进行了鉴定和测序。用内皮细胞mRNA进行核酸酶保护实验，建立转录起始(CAP)位点。对该基因5‘侧翼区的序列分析显示，在距帽区保守距离的-28到-23处有一个完美的“Tata box”。以萤火虫荧光素酶基因为报告基因进行的功能比较研究表明，该5‘侧翼区片段在转染牛主动脉内皮细胞和小鼠成纤维细胞时显示出较高的启动子活性，而在导入HeLa细胞时则没有活性。这些研究表明，这些片段含有纤溶酶原激活物抑制物1启动子，并以组织特异性的方式表达。虽然这些片段在大鼠FTO2B肝癌细胞中也是沉默的，但它们的启动子活性可以被合成的糖皮质激素地塞米松诱导40倍。启动子缺失作图实验和涉及启动子片段与异源基因融合的研究表明，地塞米松的诱导是由糖皮质激素反应元件介导的，该元件具有增强子样特性，位于纤溶酶原激活物抑制物1基因-305和+75之间的核苷酸区域。
Plasminogen activator inhibitor type 1 is an important component of the fibrinolytic system and its biosynthesis is subject to complex regulation. To study this regulation at the level of transcription, we have identified and sequenced the promoter of the human plasminogen activator inhibitor type 1 gene. Nuclease protection experiments were performed by using endothelial cell mRNA and the transcription initiation (cap) site was established. Sequence analysis of the 5' flanking region of the gene revealed a perfect "TATA box" at position -28 to position -23, the conserved distance from the cap site. Comparative functional studies with the firefly luciferase gene as a reporter gene showed that fragments derived from this 5' flanking region exhibited high promoter activity when transfected into bovine aortic endothelial cells and mouse Ltk- fibroblasts but were inactive when introduced into HeLa cells. These studies indicate that the fragments contain the plasminogen activator inhibitor type 1 promoter and that it is expressed in a tissue-specific manner. Although the fragments were also silent in rat FTO2B hepatoma cells, their promoter activity could be induced up to 40-fold with the synthetic glucocorticoid dexamethasone. Promoter deletion mapping experiments and studies involving the fusion of promoter fragments to a heterologous gene indicated that dexamethasone induction is mediated by a glucocorticoid responsive element with enhancer-like properties located within the region between nucleotides -305 and +75 of the plasminogen activator inhibitor type 1 gene.