COPPER HOMEOSTATIC MECHANISMS IN YEAST

酵母中的铜稳态机制

• 批准号: 6328940
• 负责人: Dennis R. Winge
• 金额: $ 17.46万
• 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/6328940
• 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）铜是必不可少的，但可能是 有毒的营养素。 存在稳态机制来调节细胞 铜离子的浓度，从而保持Cu平衡并最小化 铜离子的有害影响。 金属感觉系统是 金属离子稳态。 这些系统的信号通常会导致特定 与体内平衡有关的蛋白质生物合成的金属调节。 在 酵母，铜调节既由Cu介导的诱导和 Cu介导的转录抑制作用。 该赠款专注于机制 通过其中，酵母细胞感知铜离子的细胞内水平并调节 基因表达以Cu依赖性方式。 许多人的表达 酵母中涉及Cu离子摄取涉及的产品的基因特别是 被铜离子抑制。 我们证明了基因的cu衰减 表达通过Cu介导的反式激活抑制 Mac1转录因子的活性。 阐明机制 CU介导的MAC1抑制是该提案的主要重点。 Mac1中的激活结构域的活性到包含两个Cys富含Cys的区域 序列基序。 一个要检验的假设是Cu（i）与 Mac1激活域中的富含CYS富含基序是初始事件 Mac1函数的CU抑制。 概述了实验以辨别是否 抑制是通过分子内或分子间过程发生的。 一个 Mac1研究的重要特征是例子有限 转录激活函数的调节。 过度的条件 环境中的铜离子导致A的表达 产物具有保护作用的基因的不同子集。 酵母中基因表达的Cu诱导是由ACE1介导的 转录因子。 ACE1的Cu激活需要Cu（I）离子为 存在于细胞核内。 我们假设特定的核铜（i） 转运蛋白的存在类似于已知的Cu转运蛋白特有的转运蛋白 线粒体和分泌途径。 我们的目标是识别基因 ACE1的CU激活所需的产品。 如果是候选人 确定了核铜转运蛋白，我们想确定是否也 参与Cu（i）的核运输以调节MAC1功能。