Zinc-dependent regulation of gene expression

描述（由申请人提供）：锌是一种生命必需的金属元素，但过量存在时是有毒的。因此，细胞依靠机制来维持相对恒定的细胞内锌水平，尽管细胞外介质波动。为了确保锌水平维持在细胞代谢的最佳水平，锌运输或锌储存所需的基因表达通常依赖于细胞锌水平。虽然这种基因表达的变化是锌稳态的核心，但感知细胞内锌水平并介导这些变化的因素的身份在很大程度上是未知的。我们研究的长期目标是了解真核细胞如何感知和调节细胞内锌水平。为了鉴定能感应锌的蛋白质，我们利用了pombe Schizosaccharomyces的多用途遗传学。使用这个模型系统，我们已经分离出一个新的因子，这是锌依赖的基因表达调节所必需的。该因子被命名为Loz1，包含双c2h2型锌指结构域，该结构域对锌依赖性基因表达调控至关重要。本提案描述了一种结合分子，遗传和生化的方法来确定锌如何调节Loz1。具体来说，我们将研究Loz1是否直接感知锌水平，以及这是否需要双c2h2型锌指结构域。

DESCRIPTION (provided by applicant): Zinc is a metal element that is essential for life, but is toxic when present in excess. Cells therefore rely on mechanisms to maintain a relatively constant intracellular level of zinc despite fluctuations in the extracellular medium. To ensure that zinc levels are maintained at an optimal level for cell metabolism, the expression of genes necessary for zinc transport or zinc storage is often dependent upon cellular zinc levels. Although such changes in gene expression are central to zinc homeostasis, the identity of the factors that sense intracellular zinc levels and mediate these changes is largely unknown. The long-term goal of our research is to understand how eukaryotic cells sense and regulate intracellular zinc levels. To identify proteins that sense zinc, we have taken advantage of the versatile genetics of Schizosaccharomyces pombe. Using this model system we have isolated a novel factor that is required for zinc-dependent regulation of gene expression. This factor, designated Loz1, contains a double C2H2-type zinc finger domain that is essential for zinc-dependent regulation of gene expression. This proposal describes a combined molecular, genetic and biochemical approach to determine how Loz1 is regulated by zinc. Specifically, we will address whether Loz1 directly senses zinc levels, and whether this requires the double C2H2-type zinc finger domain.