Expression of HNF4α variants in pancreatic islets and Ins-1 β cells
Expression of HNF4α variants in pancreatic islets and Ins-1 β cells
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DOI：
10.1002/dmrr.870
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发表时间：
2008-10-01
影响因子：
8
通讯作者：
Rhoads, David B.
中科院分区：
文献类型：
--
作者：
Huang, Jianmin;Karakucuk, Vildan;Rhoads, David B.
背景肝细胞核因子（HNF 4 α）是一种核受体，在成人胰腺、肝脏和其他组织中对内胚层分化和细胞功能至关重要。HNF 4A基因突变导致MODY 1。多达九种蛋白质变体来自两个发育调节启动子。因为一些变体缺乏N-末端激活功能1（AF-1）和/或C-末端抑制性F结构域，所以定义它们的组织特异性调节和功能对于理解胰腺细胞行为是重要的。使用能够识别mRNA末端的每种组合的长程逆转录-聚合酶链反应（RT-PCR）策略评估胰岛、大鼠Ins-1胰岛素瘤细胞和人Hep 3B肝细胞癌细胞中的变体。通过免疫印迹与末端特异性抗体和DNA结合assessment.Results小鼠胰岛和两种细胞系表达HNF 4 α 9，缺乏AF-1和F结构域的蛋白质表达进行了验证。胰岛还表达HNF 4 α PI启动子变体HNF 4 α 1/α 2，Hep 3B细胞表达HNF 4 α 3。当在COS-7细胞中异位表达时，HNF 4 α 1、α 3、α 7和α 9各自刺激HNF 4 α依赖性启动子。未检测到含有外显子1B（HNF 4 α 4 -α 6）的变体。缺乏典型的剪接信号和物种保护反对外显子1B usage.Conclusions这是第一次报告的HNF 4 α 9在任何组织中的表达。我们的发现扩展了我们对HNF 4 α基因转录和功能的理解。这些知识可能有助于恢复或建立调节胰岛素分泌的努力。版权所有（c）2008约翰威利父子有限公司。
Background Hepatocyte nuclear factor (HNF4 alpha) is a nuclear receptor essential for endodermal differentiation and cell functions in the adult pancreas, liver, and other tissues. Mutations in the HNF4A gene cause MODY1. Up to nine protein variants arise from two developmentally regulated promoters. Because some variants lack the N-terminal activation function 1 (AF-1) and/or C-terminal inhibitory F domain, defining their tissue-specific regulation and function is important for understanding pancreatic cell behaviour.Methods Expression of HNF4 alpha. variants in islets, rat Ins-1 insulinoma cells, and human Hep3B hepatocellular carcinoma cells was assessed using a long-range reverse transcription-polymerase chain reaction (RT-PCR) strategy capable of recognizing each combination of mRNA termini. Protein expression was verified by immuno-blotting with terminus-specific antibodies and DNA-binding assays.Results Mouse islets and both cell lines express HNF4 alpha 9, which lacks both AF-1 and the F domain. Islets also expressed the HNF4 alpha PI promoter variants HNF4 alpha 1/alpha 2, and Hep3B cells expressed HNF4 alpha 3. When ectopically expressed in COS-7 cells, HNF4 alpha 1, alpha 3, alpha 7, and alpha 9 each stimulated an HNF4 alpha-dependent promoter. Variants containing exon 1B (HNF4 alpha 4 - alpha 6) were not detected. Lack of canonical splicing signals and species conservation argues against exon 1B usage.Conclusions This is the first report of HNF4 alpha 9 expression in any tissue. Our findings extend our understanding of HNF4 alpha gene transcription and function. This knowledge may be useful in efforts to recover or establish regulated insulin secretion. Copyright (c) 2008 John Wiley & Sons, Ltd.