Research for the role of dystrophic neurites in neuronal cell dysfunction of Polyglutamine disease

为了了解聚谷氨酰胺疾病的发病机制，我们研究了含有扩展多聚Q伸展的聚集体的形成机制，重点是齿状脑苍白球萎缩。我们证明了在COS7细胞中表达包含扩展多Q伸展的截短的DRPLA蛋白导致了核周聚集体的形成，这些聚集体与微管组织中心的蛋白质标记物γ微管蛋白共定位。围绕着这些聚集体的是一个坍塌的波形蛋白网络。此外，诺考达唑破坏微管可形成散布在细胞质中的小集合体。这些发现表明，含有扩展的PolyQ伸展的截短的DRPLA蛋白在细胞外围展开并形成小的聚集体。然后，我们建立了几个稳定的细胞系，它们在四环素的控制下表达多聚Q延伸。在这些细胞系中，整合位点是相同的，因此我们可以排除整合的cDNA染色体定位的影响。使用这些稳定的细胞系，我们已经看到PolyQ拉伸的周转率是不同的，未来我们将分析它们长度的不同命运对神经细胞功能，特别是他们的轴突运输系统的影响。

To understand the pathogenetic mechanisms underlying polyglutamine diseases, we investigated the mechanisms of the formation of aggregate bodies containing expanded polyQ stretches, focusing on dentatorubral-pallidoluysian atrophy (DRPLA).We demonstrated that the expression of a truncated DRPLA protein containing expanded polyQ stretches in COS-7 cells resulted in the formation of perinuclear aggregate bodies that are co-localized with γ-tubulin, a protein marker for the microtubules-organizing center (MTOC). A collapsed vimentin network surrounded these aggregate bodies. Furthermore, disruption of the microtubules with nocodazole resulted in the formation of small aggregate bodies that were scattered throughout the cytoplasm. These findings suggest that the truncated DRPLA proteins containing expanded polyQ stretches unfold and form small aggregate bodies in the cell periphery. These aggregates move on microtubules to the MTOC, where they remain as distinct "aggresomes".Then we have established several stable cell lines, which expressed polyQ stretches under control of tetracycline. In these cell lines, the integration sites are identical so we could exclude the effect of a chromosomal localization of integrated cDNA. Using these stable cell lines we have seen the turnover rates of polyQ stretch is different.In future we will analysis the effects of the difference of the fate of polyQ stretch by their length on neuronal cell function, specially their axonal transport system.