COPPER HOMEOSTATIC MECHANISMS IN YEAST

酵母中的铜稳态机制

• 批准号: 6124500
• 负责人: Dennis R. Winge
• 金额: $ 16.95万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-12-15 至 2002-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6124500
• 关键词: Saccharomyces cerevisiae; alternatives to animals in research; biological signal transduction; copper; genetic library; glutathione; homeostasis; metal metabolism; microorganism culture; microorganism metabolism; molecular cloning; transcription factor; yeasts; zinc

DESCRIPTION: (applicant's abstract) Copper is an essential, but potentially toxic nutrient. Homeostatic mechanisms exist to regulate the cellular concentration of copper ions, thus maintaining Cu balance and minimizing the deleterious effects of Cu ions. Metal sensory systems are one facet of metal ion homeostasis. Signals from these systems often result in specific metal-regulation of biosynthesis of proteins involved in homeostasis. In yeast, copper regulation consists of both Cu-mediated induction and Cu-mediated inhibition of transcription. This grant focuses on mechanisms by which yeast cells sense the intracellular level of Cu ions and regulate gene expression in a Cu-dependent manner. The expression of a number of genes encoding products involved in Cu ion uptake in yeast is specifically inhibited by Cu ions. We demonstrated that Cu-attenuation of gene expression occurs through Cu-mediated repression of the transactivation activity of the Mac1 transcription factor. Elucidation of the mechanism of Cu-mediated repression of Mac1 is a major focus of this proposal. Activation domain activity in Mac1 maps to a region containing two Cys-rich sequence motifs. One hypothesis to be tested is that Cu(I) binding to the Cys-rich motifs in the Mac1 activation domain is an initial event in Cu-repression of Mac1 function. Experiments are outlined to discern whether repression occurs through an intramolecular or intermolecular process. A significant feature of the Mac1 studies is that there are limited examples of regulation of transcriptional activation function. Conditions of excess copper ions in the environment result in the induced expression of a different subset of genes whose products have protective roles. Cu-induction of gene expression in yeast is mediated by the Ace1 transcription factor. Cu-activation of Ace1 requires Cu(I) ions to be present within the nucleus. We postulate that a specific nuclear Cu(I) transporter exists analogous to known Cu transporters specific for the mitochondrion and the secretory pathway. Our objective is to identify gene products that are required for Cu-activation of Ace1. If a candidate nuclear Cu transporter is identified, we want to determine whether it also participates in nuclear transport of Cu(I) for regulation of Mac1 function.

描述：（申请人的摘要）铜是一种必需的元素，但具有潜在的潜力 有毒营养素。 存在稳态机制来调节细胞 铜离子的浓度，从而保持铜平衡并最大限度地减少 铜离子的有害影响。 金属感觉系统是其中的一个方面 金属离子稳态。 来自这些系统的信号通常会导致特定的结果 参与稳态的蛋白质生物合成的金属调节。 在 酵母中，铜的调节包括铜介导的诱导和 Cu 介导的转录抑制。 这笔赠款重点关注机制 酵母细胞通过它感知细胞内铜离子的水平并调节 基因表达以 Cu 依赖性方式进行。 表达了一些 编码参与酵母吸收铜离子的产物的基因是特异的 受Cu离子抑制。 我们证明了基因的 Cu 衰减 表达是通过铜介导的反式激活抑制而发生的 Mac1 转录因子的活性。 阐明其机制 Cu 介导的 Mac1 抑制是该提案的主要焦点。 Mac1 中的激活域活动映射到包含两个富含 Cys 的区域 序列基序。 需要检验的一个假设是 Cu(I) 与 Mac1 激活域中富含 Cys 的基序是 Cu-抑制Mac1功能。 概述了实验来辨别是否 抑制通过分子内或分子间过程发生。 一个 Mac1 研究的显着特点是例子有限 转录激活功能的调节。 超额条件 环境中的铜离子会诱导表达 其产物具有保护作用的不同基因子集。 酵母中铜诱导基因表达是由 Ace1 介导的 转录因子。 Ace1 的 Cu 激活需要 Cu(I) 离子 存在于细胞核内。 我们假设特定的核 Cu(I) 转运蛋白的存在类似于已知的铜转运蛋白，具体针对 线粒体和分泌途径。 我们的目标是识别基因 铜激活 Ace1 所需的产品。 如果一个候选人 核铜转运蛋白已被识别，我们想确定它是否也 参与 Cu(I) 的核转运以调节 Mac1 功能。