POSITIVE REGULATION OF INSULIN GENE TRANSCRIPTION

我们研究计划的最终目标是在分子水平上 大鼠胰岛素II基因的所有顺式和反式作用元件 它们参与其在胰腺中的组织特异性表达 β细胞。特别是，我们正试图理解积极的-- 这个系统的代理组件。我们最近描述了这种老鼠的特征 胰岛素III基因5‘-包含其增强子的侧翼序列。我们 还表明存在多个离散的元素，这些元素包括 该增强子是一个-10bp的序列，位于-100至-91位 大鼠胰岛素基因II转录单位。我们检测到一种DNA结合 蛋白质，它是胰岛素产生细胞中唯一存在(活跃)的蛋白质， 它与这一重要的调控序列特别相互作用。 此外，我们最近还鉴定和分离了两个lamda-gt11-cdna 表达融合蛋白的克隆，该融合蛋白可与 齐聚-100至-91元素。我们建议进一步描述这些特性 通过纯化与顺式和反式作用元件结合的因子 -100到-91序列，克隆编码它的基因，并对两者进行研究 其促进胰岛素基因表达的作用机制 该胰岛素基因的转录和表达调控 转录调控因子本身。我们还将搜索其他 正向影响胰岛素基因转录的反式作用因子 β细胞。一旦确定了这一因素(S)，它将受到 对以上对通过-100到 -91元素。对胰岛素基因调控机制的认识 抄写是彻底、基本地了解 葡萄糖稳态及其病理状态。

The ultimate goal of our research program is to understand, in molecular terms, all of the cis- and trans-acting elements of the rat insulin II gene which are involved in its tissue-specific expression within the pancreatic beta-cell. In particular we are attempting to understand the positive- acting components of this system. We have recently characterized the rat insulin III gene 5'-flanking sequences which encompass its enhancer. We have also shown that there are multiple, discrete elements which comprise this enhancer is an -10bp sequence located t positions -100 to -91 within the rat insulin gene II transcription unit. We have detected a DNA-binding protein, which is uniquely present (active) in insulin producing cells, that specifically interacts with this important regulatory sequence. Moreover, recently we have identified and isolated two lamda-gt11-cDNA clones which express a fusion protein which specifically binds to the oligomerized -100 to -91 element. We propose to further characterize these cis- and trans-acting components by purifying the factor which binds to the -100 to -91 element, cloning the gene which encodes it and studying both its mechanism of action regarding the promotion of insulin gene transcription and the regulation of expression of this insulin gene transcriptional regulator itself. We will also search for additional trans-acting factors which positively affect insulin gene transcription in beta-cells. Once this factors(s) has been identified it will be subjected to the analyses outlined above for the factor operating through the -100 to -91 element. Understanding the mechanism of regulation of insulin gene transcription is fundamental to gaining a thorough, basic understanding of glucose homeostasis and pathological states thereof.