RNAi-mediated suppression of the mitochondrial iron chaperone, frataxin, in Drosophila
RNAi-mediated suppression of the mitochondrial iron chaperone, frataxin, in Drosophila
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DOI：
10.1093/hmg/ddi367
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发表时间：
2005-11-15
影响因子：
3.5
通讯作者：
Phillips, JP
中科院分区：
文献类型：
--
作者：
Anderson, PR;Kirby, K;Phillips, JP
线粒体铁伴侣蛋白frataxin在细胞铁稳态和Fe-S中心的合成和再生中起关键作用。共济失调蛋白的遗传缺陷与人类的弗里德赖希共济失调相关，并导致含铁蛋白（包括呼吸链组分以及线粒体和细胞溶质乌头酸酶）功能丧失。在这里，我们报告了使用RNA干扰（RNAi）抑制frataxin的多细胞真核生物，果蝇。从表型上看，果蝇frataxin同源物（dfh）的抑制在幼虫和成虫中赋予不同的表型，导致巨大的长寿幼虫和有条件的短命成虫。DFH蛋白的缺乏导致许多含血红素和含铁硫的酶的活性降低，细胞内铁稳态的丧失和对铁毒性的易感性增加。与幼虫和成虫的差异表型平行，我们的研究结果表明，dfh沉默差异失调铁蛋白表达在成人，但不是在幼虫。此外，周围神经系统中dfh的沉默，弗里德赖希的病理学的一个特定的焦点，允许正常的幼虫发育，但在成人寿命施加显着减少。相反，运动神经元中的dfh沉默对幼虫或成虫都没有有害影响。最后，过表达的Sod 1，Sod 2或Cat不能抑制DFH缺陷动物成功完成羽化的失败，这表明氧化应激在这种表型中的作用最小。果蝇中DFH缺乏所赋予的强大的发育、生化和组织特异性表型为鉴定遗传、营养和环境因素提供了一个平台，这些因素可以改善由共济失调蛋白缺乏引起的症状。
The mitochondrial iron chaperone, frataxin, plays a critical role in cellular iron homeostasis and the synthesis and regeneration of Fe-S centers. Genetic insufficiency for frataxin is associated with Friedreich's Ataxia in humans and confers loss of function of Fe-containing proteins including components of the respiratory chain and mitochondrial and cytosolic aconitases. Here, we report the use of RNA-interference (RNAi) to suppress frataxin in the multicellular eukaryote, Drosophila. Phenotypically, suppression of the Drosophila frataxin homologue (dfh) confers distinct phenotypes in larvae and adults, leading to giant long-lived larvae and to conditional short-lived adults. Deficiency of the DFH protein results in diminished activities of numerous heme- and iron-sulfur-containing enzymes, loss of intracellular iron homeostasis and increased susceptibility to iron toxicity. In parallel with the differential larval and adult phenotypes, our results indicate that dfh silencing differentially dysregulates ferritin expression in adults but not in larvae. Moreover, silencing of dfh in the peripheral nervous system, a specific focus of Friedreich's pathology, permits normal larval development but imposes a marked reduction in adult lifespan. In contrast, dfh silencing in motorneurons has no deleterious effect in either larvae or adults. Finally, overexpression of Sod1, Sod2 or Cat does not suppress the failure of DFH-deficient animals to successfully complete eclosion, suggesting a minimal role of oxidative stress in this phenotype. The robust developmental, biochemical and tissue-specific phenotypes conferred by DFH deficiency in Drosophila provide a platform for identifying genetic, nutritional and environmental factors, which ameliorate the symptoms arising from frataxin deficiency.