Mechanism of the Transcriptional Response to Transition Metals

描述（由申请人提供）：必需的二价过渡金属，如锌、铜和铁，在300多种蛋白质中起着重要的结构和催化作用。然而，这些和其他过渡金属也对生物体构成潜在威胁。如果不加以控制，这些金属可以催化自由基的产生，从而破坏所有类型的生物分子。过渡金属必须保持在生理窗口。像威尔逊氏病和门克氏病这样的疾病表明，过多或过少的金属都会导致肝脏、肾脏、神经系统和结缔组织的病变。显然，金属稳态是细胞功能的一个重要方面。这种控制的主要部分发生在转录水平上。金属反应元件结合蛋白（MTF-1）是这一调控的核心参与者之一。MTF-1是一种序列特异性的DNA结合蛋白，它感知细胞的金属状态并相应地激活基因。人们对MTF-1本身了解很多，但对帮助MTF-1有效激活转录的蛋白质辅助因子知之甚少。我们将在果蝇模型系统中使用基于RNAi的筛选，以确定金属刺激转录所需的蛋白质辅助因子。此外，我们将利用基于细胞和体外试验的组合来表征MTF-1和这些蛋白质辅助因子之间的物理和功能相互作用。最后，我们将确定果蝇基因组中的MTF-1结合位点，以确定对金属刺激作出反应的MTF-1调控。我们研究的长期目标是了解细胞如何对不同种类的金属做出反应，通过不同方式调节适当的金属反应基因来控制金属稳态。公共卫生相关性：人类对正常生长和健康所需的必需金属有营养需求。但在高剂量下，这些金属中的许多都是有毒的。可以理解的是，还需要保持这些金属的平衡。我们正在研究帮助维持这种平衡的基因。长期目标是了解对这些相同基因的放松管制是如何导致金属诱发疾病的。

DESCRIPTION (provided by applicant): Essential divalent transition metals such as zinc, copper, and iron play important structural and catalytic roles in over 300 proteins. However, these and other transition metals also pose a potential threat to an organism. Left unchecked these metals can catalyze the generation of free radicals that damage all types of biological molecules. Transition metals must be kept in a physiological window. Diseases like Wilson's disease and Menke's disease demonstrate that either too much or too little metal can lead to pathologies of the liver, kidney, nervous system and connective tissues. Clearly metal homeostasis is an important aspect of cellular function. A major part of this control occurs at the level of transcription. One of the central players in this regulation is the metal response element binding protein (MTF-1). MTF-1 is a sequence specific DNA binding protein that perceives the metal status of a cell and activates genes accordingly. A good deal is known about MTF-1 itself, but very little is known about the protein co-factors that help MTF-1 efficiently activate transcription. We will use an RNAi based screen, in the Drosophila model system, to determine what protein co-factors are required for metal stimulated transcription. In addition we will characterize the physical and functional interactions between MTF-1 and these protein co-factors using a combination of cell based and in vitro assays. Finally we will identify the MTF-1 binding sites across the Drosophila genome to define the MTF-1 regulon that responds to metal stimuli. The long-term objective of our studies is to understand how a cell, in response to a diverse set of metals, differentially regulates the appropriate metal responsive genes to control metal homeostasis. PUBLIC HEALTH RELEVANCE: Humans have a nutritional requirement for essential metals for normal growth and health. But in high doses many of these metals become toxic. Understandably, there is also a need to keep these metals in balance. We are studying the genes that help maintain this equilibrium. The long term goal is to understand how deregulation of these same genes contributes to metal induced disease.