Truncated N-terminal fragments of huntingtin with expanded glutamine repeats form nuclear and cytoplasmic aggregates in cell culture
Truncated N-terminal fragments of huntingtin with expanded glutamine repeats form nuclear and cytoplasmic aggregates in cell culture
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DOI：
10.1093/hmg/7.5.783
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发表时间：
1998-05-01
影响因子：
3.5
通讯作者：
Ross, CA
中科院分区：
文献类型：
--
作者：
Cooper, JK;Schilling, G;Ross, CA
亨廷顿氏病（HD）是由亨廷顿蛋白中编码多聚谷氨酰胺的CAG重复序列扩增引起的进行性神经退行性疾病。最近的数据表明，亨廷顿蛋白的N-末端片段可能在HD患者的神经元中聚集，在细胞质中形成营养不良的神经突，在细胞核中形成核内神经元包涵体。还发现使用亨廷顿蛋白的短N-末端片段的HD动物模型具有核内包涵体，并且该相同片段可以在体外聚集。我们现在已经开发了一种细胞培养模型，证明亨廷顿蛋白的N-末端片段与扩大谷氨酰胺重复聚集在细胞质和细胞核中。神经母细胞瘤细胞瞬时转染全长亨廷顿结构与正常或扩大重复弥漫性细胞质定位的蛋白质。与此相反，细胞转染截短的N-末端片段显示聚集只有当谷氨酰胺重复扩增。聚集体通常是泛素化的。较短的截短产物似乎在细胞核中形成更多的聚集体。用扩增的重复构建体而不是正常的重复构建体转染的细胞显示出增强的对细胞凋亡诱导剂星形孢菌素的毒性。这些数据表明，具有扩展的谷氨酰胺重复序列的亨廷顿蛋白的N-末端截短片段可以在培养的细胞中聚集，并且这种聚集对细胞可能是有毒的。该模型将有助于未来的实验，以测试聚集和毒性机制，并可能用于测试实验性治疗干预措施。
Huntington's disease (HD) is a progressive neurodegenerative disorder caused by an expanding CAG repeat coding for polyglutamine in the huntingtin protein. Recent data have suggested the possibility that an N-terminal fragment of huntingtin may aggregate in neurons of patients with HD, both in the cytoplasm, forming dystrophic neurites, and in the nucleus, forming intranuclear neuronal inclusion bodies. An animal model of HD using the short N-terminal fragment of huntingtin has also been found to have intranuclear inclusions and this same fragment can aggregate in vitro. We have now developed a cell culture model demonstrating that N-terminal fragments of huntingtin with expanded glutamine repeats aggregate both in the cytoplasm and in the nucleus. Neuroblastoma cells transiently transfected with full-length huntingtin constructs with either a normal or expanded repeat had diffuse cytoplasmic localization of the protein. In contrast, cells transfected with truncated N-terminal fragments showed aggregation only if the glutamine repeat was expanded. The aggregates were often ubiquitinated. The shorter truncated product appeared to form more aggregates in the nucleus. Cells transfected with the expanded repeat construct but not the normal repeat construct showed enhanced toxicity to the apoptosis-inducing agent staurosporine. These data indicate that N-terminal truncated fragments of huntingtin with expanded glutamine repeats can aggregate in cells in culture and that this aggregation can be toxic to cells. This model will be useful for future experiments to test mechanisms of aggregation and toxicity and potentially for testing experimental therapeutic interventions.