蛋白结合态镉是大米等食品镉污染物的主要形式，难以通过物理、化学方法脱除。活体酿酒酵母能分割蛋白质结合态镉，是解决该问题的重要突破口。蛋白结合态镉在酵母的作用下能够分解产生游离态镉。但酿酒酵母并不耐受游离态镉。前期发现酿酒酵母OLE1能响应镉胁迫，提高酿酒酵母对游离态镉的耐受性。因此，探明OLE1镉胁迫的分子响应机制，是实现其在大米等食品镉脱除领域中推广应用的前提。从镉诱发氧自由基的理论出发，在明确OLE1响应镉胁迫的表型，及Yap5对OLE1潜在的调控作用，本项目拟利用野生型和yap5∆株及RT-PCR技术，检测镉、氧自由基、YAP5缺失对OLE1表达的影响；利用GFP-YAP5菌株及蛋白亚细胞定位技术，检测镉、氧自由基对Yap5的调控作用；再利用荧光素酶报告基因表达载体及基因克隆技术，构建OLE1启动子分析质粒，证实YRE元件对镉及Yap5的响应。最终揭示OLE1的镉胁迫分子响应机制。

The protein-binding complex is the main form of cadmium in cadmium-contaminated rice and other food products, which makes it difficult to remove the cadmium from the foods with the available physical or chemical methods. Living Saccharomyces cerevisiae can be used in the cleavage of the free cadmium from the protein-cadmium complex. However, living S. cerevisiae shows a low cadmium tolerance to the free cadmium. In our previous study, a novel cadmium tolerance gene OLE1 will be up-regulated in response to cadmium stress, and confer high cadmium tolerance to living S. cerevisiae. Therefore, the promise and base for the promotion and application of the living S. cerevisiae in the field of cadmium removal from foods is to reveal the molecular mechanism of OLE1 in response to cadmium stress. Based on the theory of cadmium inducing oxygen-free radicals, the phenotype of OLE1 in response to cadmium stress and the potential role of Yap5 in regulation of OLE1, this study will firstly ascertain the effects of cadmium, oxygen-free radicals and YAP5 deletion on OLE1 expression by RT-PCR in wild type and yap5∆ strains. Secondly, the effects of cadmium, oxygen-free radicals on Yap5 will be detected by the subcellular localization of GFP-protein method in GFP-YAP5 strains. Thirdly, the plasmid for the OLE1 promoter analysis will be constructed from basic plasmid with a firefly luciferase reporter through gene cloning method, and the response YRE element in OLE1 promoter to cadmium and Yap5 will be determined. The molecular mechanism of OLE1 in response to cadmium stress will be revealed finally.