Molecular Endocrinology of Gene Regulation By cAMP

cAMP 基因调控的分子内分泌学

• 批准号: 6624077
• 负责人: PATRICK G QUINN
• 金额: $ 23.61万
• 依托单位: PENNSYLVANIA STATE UNIV HERSHEY MED CTR
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-05-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6624077
• 关键词: DNA directed RNA polymerase; biological signal transduction; cAMP response element binding protein; cell line; cyclic AMP; gene expression; genetic promoter element; genetic regulation; genetic regulatory element; genetic transcription; helicase; hormones; laboratory rat; neurotransmitters; protein protein interaction; transcription factor; transfection

The overall goal of the research described here is to understand the mechanisms used by the cAMP response element binding protein, CREB, to regulate gene transcription in the basal state and in response to signals generate by stimulation of cells with hormones and neurotransmitters. These extracellular signals activate a variety of protein kinases that phosphorylate Ser 133 in the kinase inducible domain (KID) of CREB and enhance transcription activation. In order to stimulate transcription of a target gene, it is necessary to: 1) recruit a polymerase complex to the promoter; 2) isomerize the polymerase complex to an active state capable of melting the DNA template in an ATP-dependent process; and 3) dissemble the polymerase complex to allow the polymerase to assume its stable elongating conformation in a step called promoter clearance. All of these steps can be regulated by interactions between transcription factors and the polymerase complex. In the previous cycle of this grant, we showed that the constitutive activation domain (CAD) in CREB is necessary and sufficient to mediate recruitment of a polymerase complex through interaction with the promoter recognition factor IID, and that phosphorylation of the KID in CREB stimulates the activity of this complex to facilitate subsequent steps in transcription initiation. We hypothesize that P-CREB enhances isomerization and promoter clearance by regulating the recruitment and activation of IIg and that reinitiation is primarily a recruitment phenomenon, although it could be augmented by phosphorylation of CREB. The studies described here are designed to determine: 1) which post-recruitment steps in the transcription reaction are regulated by the phospho-CREB(P-CREB); 2) which general transcription factors are required for stimulation of each of these steps; and 3) how the general factors interact, whether directly or indirectly, with P-CREB or its co- activators. This is an important question because virtually all cells and tissues rely upon some form of signaling to CREB, whether to regulate metabolite processes, growth and development of endocrine tissues, or maturation and survival of neurons. It is probable that at least some of the features of the transcription activation pathway we elucidate for P- CREB will be shared by other transcription factors regulated by different hormones.

此处描述的研究的总体目标是了解CAMP响应元件结合蛋白CREB使用的机制，以调节基础状态中的基因转录，并​​通过刺激激素和神经递质的细胞而产生的信号。这些细胞外信号激活了各种蛋白激酶，它们在CREB的激酶诱导型结构域（KID）中磷酸化Ser 133并增强转录激活。为了刺激靶基因的转录，有必要：1）向启动子募集聚合酶复合物； 2）将聚合酶复合物与能够在ATP依赖性过程中熔化DNA模板的活性状态； 3）将聚合酶复合物分解，以使聚合酶在称为启动子清除的步骤中假设其稳定的伸长构象。所有这些步骤都可以通过转录因子与聚合酶复合物之间的相互作用来调节。在该赠款的上一个循环中，我们表明，CREB中的本构激活结构域（CAD）是必要的，足以通过与启动子识别因子IID相互作用，而CREB中CREB中CRE的CREB磷酸化的磷酸化来介导了聚合酶复合物的募集，并且CREB中CRE的磷酸化可以刺激该复合物的活性，以促进随后的转录启动步骤。我们假设P-CREB通过调节IIG的募集和激活来增强异构化和启动子的清除，尽管可以通过CREB的磷酸化来增强募集现象，但重新激活主要是一种募集现象。此处描述的研究旨在确定：1）转录反应中哪些恢复后步骤由磷酸化 - 铜（P-CREB）调节； 2）刺激这些步骤中的每个步骤需要哪些一般转录因子； 3）一般因素如何与p-creb或其共同激活者直接或间接相互作用。这是一个重要的问题，因为几乎所有细胞和组织都依赖于CREB的某种形式的信号传导，是调节内分泌组织的代谢物过程，生长和发育，还是神经元的成熟和存活。我们阐明了p-creb的转录激活途径的至少某些特征将由不同激素调节的其他转录因子共享。