Cellular Defects and Altered Gene Expression in PC12 Cells Stably Expressing Mutant Huntingtin
Cellular Defects and Altered Gene Expression in PC12 Cells Stably Expressing Mutant Huntingtin
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DOI：
10.1523/jneurosci.19-13-05159.1999
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发表时间：
1999-07
期刊：
影响因子：
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通讯作者：
Shihua Li;A. Cheng;He Li;Xiao-Jiang Li
中科院分区：
文献类型：
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作者：
Shihua Li;A. Cheng;He Li;Xiao-Jiang Li
扩张的聚谷氨酰胺束导致亨廷顿蛋白和其他蛋白质在神经元核中积聚和聚集。聚谷氨酰胺蛋白的核内聚集或定位是否会引发细胞病理仍存在争议。我们建立了稳定表达含20(20Q)或150(150Q)谷氨酰胺残基的亨廷顿蛋白N端片段的嗜铬细胞瘤PC12细胞。150Q蛋白主要存在于细胞核中，而20Q蛋白则分布在细胞质中。电子显微镜检查证实，150Q蛋白大部分弥漫在细胞核内，几乎没有观察到微观聚集。与亲代PC12细胞和表达20Q的细胞相比，表达150Q的细胞形态异常，缺乏正常的轴突发育，死亡更快，更容易受到细胞凋亡的刺激。150Q细胞中这些细胞缺陷的程度与150Q蛋白的表达水平有关。差异显示PCR和表达研究表明，表达150Q的细胞已经改变了多个基因的表达，包括那些对轴突生长至关重要的基因。我们的研究表明，即使在没有聚集的情况下，核内的突变亨廷顿蛋白也能够通过干扰基因的表达而导致多种细胞缺陷。
Expanded polyglutamine tracts cause huntingtin and other proteins to accumulate and aggregate in neuronal nuclei. Whether the intranuclear aggregation or localization of a polyglutamine protein initiates cellular pathology remains controversial. We established stably transfected pheochromocytoma PC12 cells that express the N-terminal fragment of huntingtin containing 20 (20Q) or 150 (150Q) glutamine residues. The 150Q protein is predominantly present in the nuclei, whereas the 20Q protein is distributed throughout the cytoplasm. Electron microscopic examination confirmed that most of the 150Q protein is diffuse in the nucleus with very few microscopic aggregates observed. Compared with parental PC12 cells and cells expressing 20Q, cells expressing 150Q display abnormal morphology, lack normal neurite development, die more rapidly, and are more susceptible to apoptotic stimulation. The extent of these cellular defects in 150Q cells is correlated with the expression level of the 150Q protein. Differential display PCR and expression studies show that cells expressing 150Q have altered expression of multiple genes, including those that are important for neurite outgrowth. Our study suggests that mutant huntingtin in the nucleus is able to induce multiple cellular defects by interfering with gene expression even in the absence of aggregation.