Identification and functional characterization of the peroxisomal proliferator response element in rat GLUT2 promoter
Identification and functional characterization of the peroxisomal proliferator response element in rat GLUT2 promoter
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DOI：
10.2337/diabetes.49.9.1517
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发表时间：
2000-09-01
期刊：
影响因子：
7.7
通讯作者：
Ahn, Y
中科院分区：
文献类型：
--
作者：
Kim, H;Kim, J;Ahn, Y
我们在大鼠GLUT2基因的+68/+89区域发现了过氧化物酶体增殖反应元件（PPRE）。为了确定GLUTS基因中假定的PPRE （GLUT2-PPRE）是否具有功能，将GLUTS启动子-荧光素酶报告基因构建物转染到CV-1细胞中。通过共表达过氧化物酶体增殖物激活受体(PPAR)- γ和类视黄醇X受体(RXR)- α及其配体处理，提高了启动子活性；引入GLUT2-PPBE突变导致ppar - γ / rxr - α异源二聚体的转激活作用丧失，利用转染不同ppar或rxr - α表达质粒组合的CV-1细胞核提取物进行的电泳迁移量测定显示，ppar - γ和rxr - α异源二聚体优先结合GLUT2-PPRE。在HIT-T15细胞中，曲格列酮和g-顺式维甲酸可提高mt GLUTS基因启动子活性，GLUT2-PPRE突变导致启动子活性降低。此外，我们观察到曲格列酮和9-顺式维甲酸在离体大鼠原代胰岛中增加了GLUTS的转录，这些结果表明GLUT2-PPRE在胰腺β细胞中具有功能，并在GLUTS基因表达中起重要作用。这是第一份报告；在参与葡萄糖稳态的基因中发现了PPRE，并将其效应联系起来；曲格列酮对胰岛素分泌的调节作用。
We identified the peroxisomal proliferator response element (PPRE) in the +68/+89 region of the rat GLUT2 gene. To identify whether the putative PPRE in the GLUTS gene (GLUT2-PPRE) is functional, GLUTS promoter-luciferase reporter constructs were transfected into CV-1 cells. Promoter activities were increased by coexpression of peroxisomal proliferator-activated receptor (PPAR)-gamma, retinoid X receptor (RXR)-alpha, and treatment of their ligands; troglitazone and g-cis retinoic acid potentiated the transactivational effects, Introduction of mutations in GLUT2-PPBE resulted in loss of transactivational effects of the PPAR-gamma/RXR-alpha heterodimer, Electrophoretic mobility shift assay using nuclear extracts of CV-1 cells, which were transfected with various combinations of PPARs or RXR-alpha expression plasmids, revealed that heterodimers of PPAR-gamma and RXR-alpha preferentially bound to GLUT2-PPRE. In HIT-T15 cells, promoter activity of the mt GLUTS gene was increased by troglitazone and g-cis retinoic acid, and mutations of GLUT2-PPRE resulted in reduction of promoter activity. In addition, we observed increased GLUTS transcription by troglitazone and 9-cis retinoic acid in isolated rat primary islets, These results suggested that the GLUT2-PPRE is functional and plays a significant role in gene expression of GLUTS in pancreatic beta-cells. This is the first report; identifying PPRE in a gene involved in glucose homeostasis, linking the effect; of troglitazone on the regulation of insulin secretion.