• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Molecular and Cellular Biology >Bridge-1, a Novel PDZ-Domain Coactivator of E2A-Mediated Regulation of Insulin Gene Transcription
【24h】

Bridge-1, a Novel PDZ-Domain Coactivator of E2A-Mediated Regulation of Insulin Gene Transcription

机译：Bridge-1，E2A介导的胰岛素基因转录调控的新型PDZ域共激活因子

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Proteins in the E2A family of basic helix-loop-helix transcription factors are important in a wide spectrum of physiologic processes as diverse as neurogenesis, myogenesis, lymphopoeisis, and sex determination. In the pancreatic β cell, E2A proteins, in combination with tissue-specific transcription factors, regulate expression of the insulin gene and other genes critical for β-cell function. By yeast two-hybrid screening of a cDNA library prepared from rat insulinoma (INS-1) cells, we identified a novel protein, Bridge-1, that interacts with E2A proteins and functions as a coactivator of gene transcription mediated by E12 and E47. Bridge-1 contains a PDZ-like domain, a domain known to be involved in protein-protein interactions. Bridge-1 is highly expressed in pancreatic islets and islet cell lines and the expression pattern is primarily nuclear. The interaction of Bridge-1 with E2A proteins is further demonstrated by coimmunoprecipitation of in vitro-translated Bridge-1 with E12 or E47 and by mammalian two-hybrid studies. The PDZ-like domain of Bridge-1 is required for interaction with the carboxy terminus of E12. In both yeast and mammalian two-hybrid interaction studies, Bridge-1 mutants lacking an intact PDZ-like domain interact poorly with E12. An E12 mutant (E12ΔC) lacking the carboxy-terminal nine amino acids shows impaired interaction with Bridge-1. Bridge-1 has direct transactivational activity, since a Gal4 DNA-binding domain–Bridge-1 fusion protein transactivates a Gal4CAT reporter. Bridge-1 also functions as a coactivator by enhancing E12- or E47-mediated activation of a rat insulin I gene minienhancer promoter-reporter construct in transient-transfection experiments. Substitution of the mutant E12ΔC for E12 reduces the coactivation of the rat insulin I minienhancer by Bridge-1. Inactivation of endogenous Bridge-1 in insulinoma (INS-1) cells by expression of a Bridge-1 antisense RNA diminishes rat insulin I promoter activity. Bridge-1, by utilizing its PDZ-like domain to interact with E12, may provide a new mechanism for the coactivation and regulation of transcription of the insulin gene.
机译：E2A基本螺旋-环-螺旋转录因子家族中的蛋白质在广泛的生理过程中很重要，例如神经发生，肌发生，淋巴和性别确定。在胰腺β细胞中，E2A蛋白与组织特异性转录因子结合，可调节胰岛素基因和其他对β细胞功能至关重要的基因的表达。通过酵母双杂交筛选从大鼠胰岛素瘤（INS-1）细胞制备的cDNA文库，我们鉴定了一种新型蛋白Bridge-1，它与E2A蛋白相互作用，并起E12和E47介导的基因转录的共激活因子的作用。 Bridge-1包含一个PDZ样结构域，该结构域已知与蛋白质-蛋白质相互作用有关。 Bridge-1在胰岛和胰岛细胞系中高度表达，表达模式主要是核表达。通过体外翻译的Bridge-1与E12或E47的共免疫沉淀以及哺乳动物的双杂交研究，进一步证明了Bridge-1与E2A蛋白的相互作用。与E12的羧基末端相互作用需要Bridge-1的PDZ样结构域。在酵母和哺乳动物的双杂交相互作用研究中，缺乏完整PDZ样结构域的Bridge-1突变体与E12的相互作用较弱。缺少羧基末端9个氨基酸的E12突变体（E12ΔC）显示与Bridge-1的相互作用减弱。 Bridge-1具有直接的反式激活活性，因为Gal4 DNA结合域–Bridge-1融合蛋白反式激活了Gal4CAT报告基因。在瞬时转染实验中，Bridge-1还通过增强大鼠胰岛素I基因增强子启动子-报告子构建体的E12或E47介导的激活而充当共激活因子。突变体E12ΔC替代E12可降低Bridge-1对大鼠胰岛素I增强剂的共激活作用。通过表达Bridge-1反义RNA使胰岛素瘤（INS-1）细胞内源性Bridge-1失活会降低大鼠胰岛素I启动子的活性。 Bridge-1通过利用其PDZ样结构域与E12相互作用，可以为胰岛素基因的共激活和转录调控提供新的机制。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号