Expression regulation of phospholipid hydroperoxide glutathione peroxidase isoforms. Transcriptional and post-transcriptional processes

12/15-脂氧合酶（12/15-LOX）和磷脂氢过氧化物谷胱甘肽过氧化物酶（PH-GPx）在复杂的脂质氢过氧化物代谢中起对抗作用。在lox中，12/15- lox在氧合酯类脂质的能力方面是独一无二的，PH-GPx是唯一能够还原过氧化酯类脂质的谷胱甘肽过氧化物酶。PH-GPx被认为是细胞LOX通路的内源性调节剂，最近我们发现这两种酶都受到细胞因子的反向调节。在这个项目中，我们打算研究这两种酶在转录、翻译和翻译后水平上的功能相互作用的机制。为此目的，将调查以下问题：功能性12/15-LOX的过表达是否足以下调PH-GPx的表达，反之亦然，敲除12/15-LOX是否足以上调PH-GPx的表达？2. 小鼠PH-GPx基因5‘侧区域的哪一部分包含启动子（功能性启动子研究），在5’侧区域鉴定的转录因子的哪些潜在结合位点是功能性的？3. 白细胞介素-4 （IL-4）和-13 （IL-13）是否诱导了能够结合12/15-LOX和PH-GPx基因启动子的核蛋白的表达，这些潜在的转录因子是否参与了这两种酶的逆调控？

12/15-Lipoxygenases (12/15-LOX) and phospholipid hydroperoxide glutathione peroxidase (PH-GPx) are counterplayers in the metabolism of complex lipid hydroperoxides. Among LOXs, 12/15-LOXs are unique with respect to their capability of oxygenating ester lipids and PH-GPx is the only glutathione peroxidase capable of reducing hydroperoxy ester lipids. PH-GPx was identified as endogenous regulator of cellular LOX pathways and recently we found that both enzymes are inversely regulated by cytokines. In this project we intend to investigate the mechanism of the functional interplay of both enzymes on transcriptional, translational and pos-translational levels. For this purpose the following questions will be investigated: 1. Is overexpression of functional 12/15-LOX sufficient to down-regulate PH-GPx expression and does vice versa 12/15-LOX knockout up-regulate PH-GPx expression? 2. Which part of the 5'-flanking region of the murine PH-GPx gene contains the promoter (functional promoter studies) and what potential binding sites for transcription factors identified in the 5'-flanking region are functional? 3. Do interleukins-4 (IL-4) and -13 (IL-13) induce the expression of nuclear proteins capable of binding to the promoter of 12/15-LOX and PH-GPx genes and are these potential transcription factor involved in the inverse regulation of both enzymes?