Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands.
PLoS One. 2013;8(4):e60788. doi: 10.1371/journal.pone.0060788. Epub 2013 Apr 8.
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease resulting in severe muscle weakness and eventual death by respiratory failure. Although little is known about its pathogenesis, mutations in fused in sarcoma/translated in liposarcoma (FUS) are causative for familial ALS. FUS is a multifunctional protein that is involved in many aspects of RNA processing. To elucidate the role of FUS in ALS, we overexpressed wild-type and two mutant forms of FUS in HEK-293T cells, as well as knocked-down FUS expression. This was followed by RNA-Seq to identify genes which displayed differential expression or altered splicing patterns. Pathway analysis revealed that overexpression of wild-type FUS regulates ribosomal genes, whereas knock-down of FUS additionally affects expression of spliceosome related genes. Furthermore, cells expressing mutant FUS displayed global transcription patterns more similar to cells overexpressing wild-type FUS than to the knock-down condition. This observation suggests that FUS mutants do not contribute to the pathogenesis of ALS through a loss-of-function. Finally, our results demonstrate that the R521G and R522G mutations display differences in their influence on transcription and splicing. Taken together, these results provide additional insights into the function of FUS and how mutations contribute to the development of ALS.
肌萎缩侧索硬化症（ALS）是一种神经退行性疾病，导致严重的肌肉无力，并最终因呼吸衰竭而死亡。尽管其发病机制知之甚少，但肉瘤融合/脂肪肉瘤翻译（FUS）的突变是家族性 ALS 的致病原因。FUS 是一种多功能蛋白，参与 RNA 处理的许多方面。为了阐明 FUS 在 ALS 中的作用，我们在 HEK-293T 细胞中过表达了野生型和两种突变形式的 FUS，以及敲低了 FUS 的表达。随后进行了 RNA-Seq 以鉴定显示差异表达或改变剪接模式的基因。通路分析表明，野生型 FUS 的过表达调节核糖体基因，而 FUS 的敲低除了影响剪接体相关基因的表达外。此外，表达突变型 FUS 的细胞显示出与过表达野生型 FUS 的细胞更相似的全局转录模式，而与敲低条件的细胞不相似。这一观察结果表明，FUS 突变体并非通过失活功能导致 ALS 的发病机制。最后，我们的结果表明，R521G 和 R522G 突变在转录和剪接方面的影响存在差异。总之，这些结果为 FUS 的功能以及突变如何导致 ALS 的发展提供了更多的见解。
