A pancreatic β-cell-specific enhancer in the human PIX-1 gene is regulated by hepatocyte nuclear factor 3β (HNF-3β), HNF-1α, and SPs transcription factors
A pancreatic β-cell-specific enhancer in the human PIX-1 gene is regulated by hepatocyte nuclear factor 3β (HNF-3β), HNF-1α, and SPs transcription factors
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DOI：
10.1074/jbc.m009088200
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发表时间：
2001-05-18
影响因子：
4.8
通讯作者：
Melloul, D
中科院分区：
文献类型：
--
作者：
Ben-Shushan, E;Marshak, S;Melloul, D
PDX-1转录因子在胰腺发育中起关键作用。虽然在早期阶段在所有细胞中都有表达，但在成人中主要局限于β细胞，为了鉴定人PDX-1基因在β细胞中表达所必需的调控元件和潜在的转录因子，我们构建了该基因5‘侧翼区的一系列5’和3‘缺失片段，与荧光素酶报告基因融合。在本报告中，我们通过瞬时转染在β细胞和非β细胞中鉴定了一个新的β细胞特异性末端增强子元件，位于-3.7和-3.45kb之间，DNaseI足迹分析揭示了两个保护区。其中一个结合转录因子SP1和SP3，另一个结合肝细胞核因子3β(HNF-3β)和HNF-1α，共转染实验表明HNF-3β、HNF-1α和SP1是本文描述的人PDX-I增强子元件的正调控因子。此外，每个基序中的突变取消了相应因子(S)的结合，并显著削弱了增强子活性，因此表明这些因子之间存在协同作用。
The PDX-1 transcription factor plays a key role in pancreas development. Although expressed in all cells at the early stages, in the adult it is mainly restricted to the beta -cell, To characterize the regulatory elements and potential transcription factors necessary for human PDX-1 gene expression in beta -cells, we constructed a series of 5' and 3' deletion fragments of the 5'-flanking region of the gene, fused to the luciferase reporter gene, In this report, we identify by transient transfections in beta- and non-beta -cells a novel beta -cell-specific distal enhancer element located between -3.7 and -3.45 kilobases, DNase I footprinting analysis revealed two protected regions, one binding the transcription factors SP1 and SP3 and the other hepatocyte nuclear factor 3 beta (HNF-3 beta) and HNF-1 alpha, Cotransfection experiments suggest that HNF-3 beta, HNF-1 alpha, and SP1 are positive regulators of the herein-described human PDX-I enhancer element. Furthermore, mutations within each motif abolished the binding of the corresponding factor(s) and dramatically impaired the enhancer activity, therefore suggesting cooperativity between these factors.