THE RESTRICTED PROMOTER ACTIVITY OF THE LIVER TRANSCRIPTION FACTOR HEPATOCYTE NUCLEAR FACTOR-3-BETA INVOLVES A CELL-SPECIFIC FACTOR AND POSITIVE AUTOACTIVATION
THE RESTRICTED PROMOTER ACTIVITY OF THE LIVER TRANSCRIPTION FACTOR HEPATOCYTE NUCLEAR FACTOR-3-BETA INVOLVES A CELL-SPECIFIC FACTOR AND POSITIVE AUTOACTIVATION
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DOI：
10.1128/mcb.12.2.552
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发表时间：
1992-02-01
影响因子：
5.3
通讯作者：
COSTA, RH
中科院分区：
文献类型：
--
作者：
PANI, L;QIAN, XB;COSTA, RH
转录因子肝细胞核因子3 （HNF-3）参与多个肝脏基因的协调表达。HNF-3 DNA结合活性由三种不同的肝脏蛋白组成，它们识别相同的DNA位点。HNF-3蛋白（指定- α， β和γ）在DNA结合域和其他几个区域具有同源性。为了了解hnf -3- β的细胞特异性表达，我们定义了引发肝癌特异性表达的调控序列。启动子活性需要- 134 bp的hnf -3- β近端序列，并结合四种核蛋白，包括两种普遍存在的因子。其中一个启动子位点与一种新的细胞特异性因子lf - h3 - β相互作用，其结合活性与hnf -3- β组织表达模式相关。此外，HNF-3蛋白在其自身启动子内存在一个结合位点，这表明HNF-3 β表达的建立涉及自激活机制。我们认为lf - h3 - β和HNF-3位点在HNF-3- β转录因子的细胞特异性表达中都起着重要作用。
The transcription factor hepatocyte nuclear factor 3 (HNF-3) is involved in the coordinate expression of several liver genes. HNF-3 DNA binding activity is composed of three different liver proteins which recognize the same DNA site. The HNF-3 proteins (designated-alpha, beta, and gamma) possess homology in the DNA binding domain and in several additional regions. To understand the cell-type-specific expression of HNF-3-beta, we have defined the regulatory sequences that elicit hepatoma-specific expression. Promoter activity requires - 134 bp of HNF-3-beta proximal sequences and binds four nuclear proteins, including two ubiquitous factors. One of these promoter sites interacts with a novel cell-specific factor, LF-H3-beta, whose binding activity correlates with the HNF-3-beta tissue expression pattern. Furthermore, there is a binding site for the HNF-3 protein within its own promoter, suggesting that an autoactivation mechanism is involved in the establishment of HNF-3-beta expression. We propose that both the LF-H3-beta and HNF-3 sites play an important role in the cell-type-specific expression of the HNF-3-beta transcription factor.