Charakterization of mice lacking functional mitochondrial thioredoxin reductase (TR2): tissue-specific gene targeting

缺乏功能性线粒体硫氧还蛋白还原酶（TR2）的小鼠的特征：组织特异性基因靶向

• 批准号: 5241270
• 负责人: Dr. Markus Brielmeier
• 金额: --
• 依托单位: Abteilung für Vergleichende Medizin (AVM) (aufgelöst)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2000
• 资助国家: 德国
• 起止时间: 1999-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5241270?language=en
• 关键词: Charakterization; mice; lacking; functional; mitochondrial

Glutathione peroxidases (GPxs) and thioredoxin reductases (TRxRs) are selenoproteins playing a crucial role in protecting cells from oxidative damage. There are at least four different GPxs and two different TRxRs in mammalian cells which differ in their site of expression, intracellular localization and/or substrate specificity. GPxs reduce peroxides at the expense of reduced glutathione (GSH). Oxidized glutathione (GSSG) is recycled to GSH through glutathione reductase and NADPH. Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is unique among the glutathione peroxidases for its substrate specificity, its localization at various sites including mitochondria and its high position in the hierarchy of selenoproteins during selenium deprivation. PHGPx is the only glutathione peroxidase that is able to reduce phospholipid hydroperoxides and that also accepts LDL hydroperoxides and cholesterol hydroperoxides as substrates.Thioredoxin reductases, by oxidizing NADPH, regenerate thioredoxins which serve as electron donors in a variety of redox reactions. One of the two known thioredoxin reductases (TRxR2) is localized to mitochondria. The two selenoproteins PHGPx and TRxR2, together with mitochondrial peroxiredoxin and superoxide dismutase, represent the primary line of defense in mitochondria against reactive oxygen intermediates produced by the respiratory chain as a side product of oxygen reduction. To study the expression pattern of PHGPx and TRxR2 at a cellular level and to elucidate their function in vivo, we propose to (i) insert the lacZ gene into the genomic PHGPx and TRxR2 loci and (ii) to knock out the genes in mice. Since PHGPx and TRxR2 might be vitally required, we shall also (iii) generate conditional PHGPx and TRxR2 alleles and shall attempt to knock out the genes in mice in vivo in a tissue specific manner using the CRE-loxP system. We shall investigate the susceptibility of PHGPx and TRxR2 k.o. mice to oxidative stress and the induction of apoptosis.

谷胱甘肽过氧化物酶 (GPx) 和硫氧还蛋白还原酶 (TRxR) 是硒蛋白，在保护细胞免受氧化损伤方面发挥着至关重要的作用。哺乳动物细胞中至少有四种不同的 GPx 和两种不同的 TRxR，它们的表达位点、细胞内定位和/或底物特异性不同。 GPx 可以减少过氧化物，但会减少还原型谷胱甘肽 (GSH)。氧化型谷胱甘肽 (GSSG) 通过谷胱甘肽还原酶和 NADPH 回收为 GSH。磷脂氢过氧化物谷胱甘肽过氧化物酶 (PHGPx) 在谷胱甘肽过氧化物酶中是独一无二的，因为它具有底物特异性、定位于包括线粒体在内的多个位点以及缺硒期间在硒蛋白层次中的较高位置。 PHGPx 是唯一能够还原磷脂氢过氧化物并接受 LDL 氢过氧化物和胆固醇氢过氧化物作为底物的谷胱甘肽过氧化物酶。硫氧还蛋白还原酶通过氧化 NADPH，再生硫氧还蛋白，硫氧还蛋白在各种氧化还原反应中充当电子供体。两种已知的硫氧还蛋白还原酶 (TRxR2) 之一定位于线粒体。两种硒蛋白 PHGPx 和 TRxR2 与线粒体过氧化还原蛋白和超氧化物歧化酶一起，代表线粒体中针对呼吸链产生的活性氧中间体（作为氧还原的副产物）的主要防线。为了在细胞水平上研究 PHGPx 和 TRxR2 的表达模式并阐明它们的体内功能，我们建议 (i) 将 lacZ 基因插入基因组 PHGPx 和 TRxR2 位点，以及 (ii) 在小鼠中敲除这些基因。由于 PHGPx 和 TRxR2 可能是至关重要的，我们还应 (iii) 生成条件 PHGPx 和 TRxR2 等位基因，并尝试使用 CRE-loxP 系统以组织特异性方式在体内敲除小鼠体内的基因。我们将研究 PHGPx 和 TRxR2 k.o. 的敏感性。小鼠氧化应激和诱导细胞凋亡。