REGULATED EXPRESSION OF CATECHOLAMINE BIOSYNTHESIS GENES

描述：神经递质系统的开发和维护 是神经功能发生和发展的关键事件之一 专一性。影响神经递质表型的事件 指定的单元格在开发期间启动并继续 出生后。环境刺激和位置信息刺激 导致神经递质产生的细胞内信号。在……里面 几乎所有被研究的情况都是关键的决定性监管事件 编码基因的激活或抑制，这种酶产生 神经递质。这项建议旨在了解基因和 胸径和TH基因的生化调节元件 对恰当的表达至关重要。在上一个批准期内， 申请者鉴定了一种同源结构域转录因子，名为Arix 它与胸径基因结合，并选择性地在 去甲肾上腺素能细胞。ARiX将调节DBH基因转录，但它是 依赖cAMP第二信使的同时激活 路径。ARiX还将刺激胸腺激素基因的转录， 独立于第二信使刺激。除 正性基因组调控元件的特征，它们 描述了胸径基因的一个负调控元件 功能是抑制不适当细胞中的表达。 在这个拟议的授权期内，目标是定义分子和 这些遗传调控事件背后的生化机制，以及 开始测试这些调节元件在体内的重要性。至 为了实现这一目标，参与转录的蛋白质 TH和胸径的调节将被识别和表征。这个 这些因素改变特定基因表达的机制将 在培养细胞和确定的生化系统中进行评估。在……里面 此外，胸径的一个已定义的管理要素的重要性 转基因基因的构建将在体内进行评估 动物。这些实验可能对理解 神经内分泌细胞执行其特化的过程 功能。 具体目标有4个：1.明确生化和分子生物学 新发现的同源结构域因子Arix和Arix的相互作用 胸腺激素基因协同刺激的cAMP系统 理解两者之间区别的基础 Arix介导的转录激活所需的DBH基因； 3.鉴定和鉴定与胸径相互作用的蛋白质 消音器；4.评估Cre/Arix监管要素的重要性 通过将含有该元件突变的DNA导入体内 老鼠。

DESCRIPTION: The development and maintenance of a neurotransmitter system is one of the essential events in the generation of neural function and specificity. The events that influence the neurotransmitter phenotype of a specified cell are initiated during development and continue postnatally. Environmental stimuli and positional information stimulate intracellular signals that lead to neurotransmitter production. In nearly all situations studied the critical decisive regulatory event is the activation or repression of genes encoding the enzymes producing the neurotransmitter. This proposal aims to understand the genetic and biochemical regulatory elements of the DBH and TH genes that are critical for appropriate expression. In the previous granting period the applicants identified a homeodomain transcription factor termed, Arix which binds to the DBH gene and is expressed selectively in noradrenergic cells. Arix will regulate DBH gene transcription but it is dependent upon simultaneous activation of the cAMP second messenger pathway. Arix will also stimulate transcription of the DBH gene, independent of second messenger stimulation. In addition to the characterization of the positive genomic regulatory elements, they characterized a negative regulatory element of the DBH gene which functions to repress expression in the inappropriate cells. In this proposed granting period the goal is to define the molecular and biochemical mechanisms underlying these genetic regulatory events, and to begin testing the importance of these regulatory element in vivo. To achieve this goal the proteins that contribute to transcriptional regulation of TH and DBH will be identified and characterized. The mechanism by which these factors modify specific gene expression will be evaluated in cultured cells and in defined biochemical systems. In addition, the importance of one defined regulatory element of the DBH gene will be evaluated in vivo though construction of transgeneic animals. These experiments could be significant towards understanding the process by which a neuroendocrine cell carries out its specialized function. There are 4 specific aims: 1. Define the biochemical and molecular interactions between the newly identified homeodomain factor, Arix, and the cAMP system which leads to synergistic stimulation of DBH gene expression.; 2. Understand the basis of the difference between TH and DBH genes in requirements for Arix mediated transcriptional activation; 3. Identify and characterize the protein that interacts with the DBH silencer.; 4. Evaluate the importance of the CRE/Arix regulatory element in vivo by introduction of DNA containing mutation of this element into mice.