PDX-1,A TRANSCRIPTIONAL ACTIVATOR OF THE INSULIN GENE

描述：(改编自申请人的摘要)。PDX-1同源结构域 转录因子是两个早期胰腺的重要调节因子 成人胰岛β细胞的发育和胰岛素基因表达。在 在胰腺，PDX-1的表达本质上仅限于胰岛β细胞。这个 这项提案中概述的研究将集中在两个悬而未决的问题上 关于PDX-1的生物学功能。首先，申请者将工作 朝向确定和表征直接指导 PDX-1基因转录到β细胞。瞬变 申请人已进行的转基因和转基因实验 证实小鼠PDX-1基因的选择性表达是由 核酸酶超敏位点-1的5‘侧翼控制区序列 (HSSa；-2560到-1880/-150个碱基)。此外，对启动子区域的分析 人和鸡的PDX-1基因的唯一区域 在HSS1中发现了与小鼠显著的序列相似性。这一地区 根据序列可进一步划分为三个亚区 保护和功能，命名为区域I(-2694到-2561BP)，区域 II区(-2139~-1958 BP)和III区(-1879~-1799 BP)。很有可能 老鼠、鸡和人类之间保守的序列定义了 PDX-1基因的顺式活性元件对适当的 发育和成体胰岛特异表达。其次，申请者将 致力于确定PDX-1蛋白的动作电位是如何 在β细胞中被调节。他们的研究表明，脑细胞的活动 PDX-1激活结构域被最重要的生理学作用增强 β细胞功能的调节因子--葡萄糖和通过功能相互作用 与其他富含β细胞的激活剂一起使用。此外，p300/CBP 共激活子由PDX-1介导胰岛素基因转录。 了解PDX-1的反式激活潜力是如何控制的 洞察调控PDX-1诱导的机制 在正常和致病条件下的β细胞转录。

DESCRIPTION: (Adapted from the applicant's abstract). The PDX-1 homeodomain transcription factor is an essential regulator of both early pancreas development and insulin gene expression in adult islet beta cells. In the pancreas, PDX-1 expression is essentially restricted to islet beta cells. The studies outlined in this proposal will focus on two outstanding issues regarding the biological function of PDX-1. First, the applicant will work towards identifying and characterizing the key DAN-binding factors that direct transcription of the pdx-1 gene specifically to beta cells. Transient transfection and transgenic experiments that the applicant has performed have demonstrated that selective expression of the mouse pdx-1 gene is mediated by 5'-flanking control region sequences spanning nuclease hypersensitive site-1 (HSSa; -2560 to -1880 +/- 150 bp). Furthermore, analysis of the promoter region of the human and chicken pdx-1 genes has revealed that the only area of significant sequence similarity with the mouse is found in HSS1. This region could be further divided into three subdomains as a result of sequence conservation and function, which were termed Area I (-2694 to -2561 bp), Area II (-2139 to -1958 bp), and Area III (-1879 to -1799 bp). It is very likely that the sequences conserved between mouse, chicken, and human define the cis-active elements of the pdx-1 gene that are critical for appropriate developmental and adult islet specific expression. Second, the applicant will work towards determining how the action potential of the PDX-1 protein is regulated in beta cells. Their studies have shown that the activity of the PDX-1 activation domain is potentiated by the most important physiological regulator of beta cell function, glucose, and through functional interactions with other beta cell-enriched activators. In addition, that the p300/CBP coactivator was recruted by PDX-1 mediate insulin gene transcription. Understanding how the trans-activation potential of PDX-1 is controlled should provide insight into the mechanisms involved in regulating PDX-1 induced transcription in beta cells under both normal and pathogenic conditions.