Huntingtin Aggregation Kinetics and Their Pathological Role in a Drosophila Huntington’s Disease Model
Huntingtin Aggregation Kinetics and Their Pathological Role in a Drosophila Huntington’s Disease Model
复制标题
DOI：
10.1534/genetics.111.133710
复制
发表时间：
2012-02
期刊：
影响因子：
3.3
通讯作者：
K. Weiss;Y. Kimura;Wyan-Ching Mimi Lee;J. Littleton
中科院分区：
文献类型：
--
作者：
K. Weiss;Y. Kimura;Wyan-Ching Mimi Lee;J. Littleton
亨廷顿病是一种神经退行性疾病，由亨廷顿蛋白中的聚谷氨酰胺束扩张引起。突变的Huntingtin在神经元内形成细胞内聚集体，尽管尚不清楚聚集体或更易溶的蛋白质形式是否代表致病物种。为了研究聚集和神经退行性变之间的联系，我们培育了表达荧光标记的人类亨廷顿蛋白的黑腹果蝇转基因菌株，编码致病(Q138)或非致病(Q15)蛋白，从而可以在活体动物中成像亨廷顿蛋白的表达和聚集。致病的亨廷顿蛋白在神经元中的表达可导致成体致死，并伴随着神经元胞体和神经突细胞质内的大聚集体的形成。对致病亨廷顿的实时成像和荧光漂白后恢复(FRAP)分析表明，新的聚集体可以在12小时内在神经元中形成，而先前存在的聚集体在几分钟内迅速积累新的亨廷顿蛋白。为了研究聚集体在病理学中的作用，我们使用覆盖果蝇基因组∼80%的缺陷，对Huntingtin-Q138聚集或Huntingtin-Q138诱导的致死性进行了单倍体不足抑制筛选。我们在我们的屏幕上识别了两类相互作用的抑制因子：一类是在降低Huntingtin表达和聚集的同时挽救生存能力的抑制因子，另一类是在不破坏Huntingtin聚集的情况下拯救生存能力的抑制因子。最强的抑制物降低了可溶的和聚集的亨廷顿蛋白水平，这表明毒性可能与亨廷顿病中的这两种形式的突变蛋白有关。
Huntington’s disease is a neurodegenerative disorder resulting from expansion of a polyglutamine tract in the Huntingtin protein. Mutant Huntingtin forms intracellular aggregates within neurons, although it is unclear whether aggregates or more soluble forms of the protein represent the pathogenic species. To examine the link between aggregation and neurodegeneration, we generated Drosophila melanogaster transgenic strains expressing fluorescently tagged human huntingtin encoding pathogenic (Q138) or nonpathogenic (Q15) proteins, allowing in vivo imaging of Huntingtin expression and aggregation in live animals. Neuronal expression of pathogenic Huntingtin leads to pharate adult lethality, accompanied by formation of large aggregates within the cytoplasm of neuronal cell bodies and neurites. Live imaging and Fluorescence Recovery After Photobleaching (FRAP) analysis of pathogenic Huntingtin demonstrated that new aggregates can form in neurons within 12 hr, while preexisting aggregates rapidly accumulate new Huntingtin protein within minutes. To examine the role of aggregates in pathology, we conducted haplo-insufficiency suppressor screens for Huntingtin-Q138 aggregation or Huntingtin-Q138–induced lethality, using deficiencies covering ∼80% of the Drosophila genome. We identified two classes of interacting suppressors in our screen: those that rescue viability while decreasing Huntingtin expression and aggregation and those that rescue viability without disrupting Huntingtin aggregation. The most robust suppressors reduced both soluble and aggregated Huntingtin levels, suggesting toxicity is likely to be associated with both forms of the mutant protein in Huntington’s disease.