Cell-specific expression of the glucose-dependent insulinotropic polypeptide gene functions through a GATA and an ISL-1 motif in a mouse neuroendocrine tumor cell line
Cell-specific expression of the glucose-dependent insulinotropic polypeptide gene functions through a GATA and an ISL-1 motif in a mouse neuroendocrine tumor cell line
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DOI：
10.1016/s0167-0115(03)00046-6
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发表时间：
2003-05-15
影响因子：
--
通讯作者：
Wolfe, MM
中科院分区：
文献类型：
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作者：
Jepeal, LI;Boylan, MO;Wolfe, MM
背景/目标：葡萄糖依赖性促胰岛素多肽（GIP）是一种42个氨基酸的胃肠调节肽，在葡萄糖存在下，刺激β细胞分泌胰岛素。GIP在胃肠K细胞中表达。先前对GIP启动子的分析表明，需要启动子的193个碱基来指导细胞特异性表达。在这里，我们试图确定和表征所涉及的转录因子。结果如下：通过对神经内分泌细胞系（STC-1）中GIP启动子的突变分析，我们确定了位于碱基-193和-182以及碱基-156和-151之间的两个区域，当独立改变时，分别导致转录减少90%和85%。当我们将这两个区域与转录因子数据库中已知的基序进行比较时，我们确定了顺式元件作为潜在的加塔和ISL-1结合位点。随后的电泳迁移率变动分析（EMSA）使用STC-1核提取物，我们证明了这些区域形成特异性DNA蛋白复合物的能力。此外，我们利用抗血清来确认加塔-4与上游位点和ISL-1与下游元件的特异性结合。结论：这些发现为转录因子加塔-4和ISL-1参与GIP基因的细胞特异性表达提供了证据。(C)2003 Elsevier Science B. V.保留所有权利。
Background/aims: Glucose-dependent insulinotropic polypeptide (GIP) is a 42-amino acid gastrointestinal regulatory peptide that, in the presence of glucose, stimulates insulin secretion from beta-cells. GIP is expressed in gastrointestinal K-cells. Prior analysis of the GIP promoter demonstrated that 193 bases of the promoter are required to direct cell specific expression. Here we sought to identify and characterize the transcription factors involved. Results: By mutational analysis of the GIP promoter in a neuroendocrine cell line (STC-1), we identified two regions located between bases - 193 and - 182 and bases - 156 and - 151 that, when independently altered, were responsible for a 90% and 85% reduction in transcription, respectively. When we compared these two regions with known motifs from transcription factor databases, we identified the cis elements as potential GATA and ISL-1 binding sites. With subsequent electrophoretic mobility shift analysis (EMSA) using STC-1 nuclear extracts, we demonstrated the ability of these regions to form specific DNA protein complexes. Furthermore, we utilized antisera to confirm the specific binding of GATA-4 to the upstream site and ISL-1 to the downstream element. Conclusion: These findings provide evidence for the involvement of the transcription factors GATA-4 and ISL-1 in the cell-specific expression of the GIP gene. (C) 2003 Elsevier Science B.V. All rights reserved.