Campuzano V, Montermini L, Lutz Y, Cova L, Hindelang C, Jiralerspong S, Trottier Y, Kish S J, Faucheux B, Trouillas P, Authier F J, Dürr A, Mandel J L, Vescovi A, Pandolfo M, Koenig M
Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM-CNRS-ULP, Illkirch, France.
Hum Mol Genet. 1997 Oct;6(11):1771-80. doi: 10.1093/hmg/6.11.1771.
Friedreich ataxia is a progressive neurodegenerative disorder caused by loss of function mutations in the frataxin gene. In order to unravel frataxin function we developed monoclonal antibodies raised against different regions of the protein. These antibodies detect a processed 18 kDa protein in various human and mouse tissues and cell lines that is severely reduced in Friedreich ataxia patients. By immunocytofluorescence and immunocytoelectron microscopy we show that frataxin is located in mitochondria, associated with the mitochondrial membranes and crests. Analysis of cellular localization of various truncated forms of frataxin expressed in cultured cells and evidence of removal of an N-terminal epitope during protein maturation demonstrated that the mitochondrial targetting sequence is encoded by the first 20 amino acids. Given the shared clinical features between Friedreich ataxia, vitamin E deficiency and some mitochondriopathies, our data suggest that a reduction in frataxin results in oxidative damage.
弗里德赖希共济失调是一种由铁硫蛋白基因功能丧失突变引起的进行性神经退行性疾病。为了阐明铁硫蛋白的功能，我们制备了针对该蛋白不同区域的单克隆抗体。这些抗体在各种人类和小鼠组织及细胞系中检测到一种加工后的18 kDa蛋白，而在弗里德赖希共济失调患者中该蛋白严重减少。通过免疫细胞荧光和免疫细胞电子显微镜技术，我们发现铁硫蛋白位于线粒体中，与线粒体膜和嵴相关。对培养细胞中表达的各种截短形式的铁硫蛋白的细胞定位分析以及蛋白质成熟过程中N端表位去除的证据表明，线粒体靶向序列由前20个氨基酸编码。鉴于弗里德赖希共济失调、维生素E缺乏症和一些线粒体疾病之间存在共同的临床特征，我们的数据表明铁硫蛋白减少会导致氧化损伤。
