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：（申请人摘要）铜是一种必不可少的，但可能 有毒营养素 稳态机制存在调节细胞 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 金属离子稳态 来自这些系统的信号通常会导致特定的 金属--参与体内平衡的蛋白质生物合成的调节。 在 酵母，铜调节包括铜介导的诱导和 Cu介导的转录抑制。 这项赠款侧重于机制 酵母细胞通过其感知细胞内的Cu离子水平并调节 以Cu依赖的方式表达基因。 一些的表达 酵母中参与Cu离子摄取的编码产物的基因是特异性的， 被Cu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发生 Mac 1转录因子的活性。 阐明了 Cu介导的Mac 1抑制是该提议的主要焦点。 Mac 1中的激活结构域活性映射到包含两个富含Cys的区域 序列基序 待检验的一个假设是，Cu（I）结合到 Mac 1激活结构域中富含Cys的基序是Mac 1激活的初始事件。 Cu抑制Mac 1功能。 实验概述，以辨别是否 阻遏通过分子内或分子间过程发生。 一 Mac 1研究的一个显著特点是， 转录激活功能的调节。 超额条件 环境中的铜离子导致诱导表达 不同的基因子集，其产物具有保护作用。 Ace 1介导Cu诱导酵母基因表达 转录因子 Ace 1的Cu活化需要Cu（I）离子被 存在于细胞核内。 我们假设，一个特定的核Cu（I） 转运蛋白类似于已知的Cu转运蛋白，特异性针对 微囊和分泌途径。 我们的目标是找出 Ace 1的Cu激活所需的产品。 如果候选人 核铜转运蛋白被确定，我们想确定它是否也 参与Cu（I）的核转运以调节Mac 1的功能。