Transgenic mice overexpressing methionine sulfoxide reductase A: characterization of embryonic fibroblasts.
Transgenic mice overexpressing methionine sulfoxide reductase A: characterization of embryonic fibroblasts.
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DOI：
10.1016/j.freeradbiomed.2010.05.017
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发表时间：
2010-08-15
影响因子：
7.4
通讯作者：
Levine, Rodney L.
中科院分区：
文献类型：
--
作者：
Zhao, Hang;Kim, Geumsoo;Liu, Chengyu;Levine, Rodney L.
关键词：
蛋白质中的蛋氨酸残基可被活性氧氧化生成蛋氨酸亚砜。需氧生物具有能够将甲硫氨酸亚砜还原回甲硫氨酸的甲硫氨酸亚砜还原酶。甲硫氨酸亚砜还原酶A作用于甲硫氨酸亚砜的S-差向异构体，并且已知通过基因消融或过表达改变其细胞水平对从微生物到动物的物种的氧化应激抗性和寿命具有显著影响。在哺乳动物中，这种酶存在于细胞质和线粒体中，本研究旨在评估每个亚细胞区室的还原酶活性对抗氧化应激的贡献。非转基因小鼠胚胎成纤维细胞缺乏甲硫氨酸亚砜还原酶A活性，提供了一种方便的细胞类型，以确定每个隔室中酶表达的影响。我们用甲硫氨酸亚砜还原酶A建立了转基因小鼠，靶向细胞质、线粒体或两者，并研究了来自每个品系的胚胎成纤维细胞。出乎意料的是，没有一个转基因细胞获得对各种氧化应激的抗性，即使表达的酶在体外测定时具有催化活性。注意到体内活性需要硫氧还蛋白和硫氧还蛋白还原酶，我们测定了这些蛋白在成纤维细胞中的水平，发现它们在非转基因和转基因细胞中都非常低。我们的结论是，甲硫氨酸亚砜还原酶A的过度表达并没有赋予抗氧化应激，因为细胞缺乏其他蛋白质所需的构成一个功能性的甲硫氨酸亚砜还原系统。
Methionine residues in protein can be oxidized by reactive oxygen species to generate methionine sulfoxide. Aerobic organisms have methionine sulfoxide reductases capable of reducing methionine sulfoxide back to methionine. Methionine sulfoxide reductase A acts on the S-epimer of methionine sulfoxide, and it is known that altering its cellular level by genetic ablation or overexpression has notable effects on resistance to oxidative stress and on lifespan in species from microorganisms to animals. In mammals, the enzyme is present both in the cytosol and mitochondria, and this study was undertaken to assess the contribution of each subcellular compartment’s reductase activity to resistance against oxidative stresses. Non-transgenic mouse embryonic fibroblasts lack methionine sulfoxide reductase A activity, providing a convenient cell type to determine the effect of expression of the enzyme in each compartment. We created transgenic mice with methionine sulfoxide reductase A targeted to the cytosol, mitochondria, or both and studied embryonic fibroblasts derived from each line. Unexpectedly, none of the transgenic cells gained resistance to a variety of oxidative stresses even though the expressed enzymes were catalytically active when assayed in vitro. Noting that activity in vivo requires thioredoxin and thioredoxin reductase, we determined the levels of these proteins in the fibroblasts and found that they were very low in both the non-transgenic and transgenic cells. We conclude that overexpression of methionine sulfoxide reductase A did not confer resistance to oxidative stress because the cells lacked other proteins required to constitute a functional methionine sulfoxide reduction system.
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影响因子：
3.8
作者：
He, Xiaoqing;Lin, Gary X.;Ma, Qiang
通讯作者：
Ma, Qiang
影响因子：
3.7
作者：
HAYFLICK, L;MOORHEAD, PS
通讯作者：
MOORHEAD, PS
影响因子：
5.1
作者：
Naoi, M;Maruyama, W;Tanaka, M
通讯作者：
Tanaka, M
影响因子：
4.8
作者：
Cabreiro, Filipe;Picot, Cedric R.;Petropoulos, Isabelle
通讯作者：
Petropoulos, Isabelle
DOI：
10.1016/s0034-5687(01)00306-1
发表时间：
2001-11-15
期刊：
RESPIRATION PHYSIOLOGY
影响因子：
--
作者：
Erecinska, M;Silver, IA
通讯作者：
Silver, IA