Aberrant splicing of tau pre-mRNA caused by intronic mutations associated with the inherited dementia frontotemporal dementia with parkinsonism linked to chromosome 17
Aberrant splicing of tau pre-mRNA caused by intronic mutations associated with the inherited dementia frontotemporal dementia with parkinsonism linked to chromosome 17
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DOI：
10.1128/mcb.20.11.4036-4048.2000
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发表时间：
2000-06-01
影响因子：
5.3
通讯作者：
Wu, JY
中科院分区：
文献类型：
--
作者：
Jiang, ZH;Cote, J;Wu, JY
额颞叶痴呆占痴呆病例的很大一部分。与17号染色体相关的帕金森病额颞叶痴呆与tau基因的外显子或内含子突变有关。这突出了异常前mrna剪接参与神经退行性疾病的发病机制。对这些疾病剪接缺陷的分子机制知之甚少。为了建立一个研究前mrna剪接在神经退行性疾病中的作用的模型系统，我们构建了一个tau迷你基因，该基因在培养细胞和体外生化分析中都能复制tau选择性剪接。我们证明了人类tau基因非保守内含子区域的突变导致外显子10和外显子11之间剪接增加。系统的生化分析表明，U1 snRNP和U6 snRNP在区分野生型和内含子突变型tau前mrna方面的重要性较小。用纯化的U1 snRNP和寡核苷酸导向的RNase H切割实验进行的凝胶迁移转移实验支持这样的观点，即内含子突变破坏了分离tau pre-mRNA中10外显子下游5'剪接位点的茎环结构，导致U1 snRNP结合和外显子10和外显子11之间剪接的增加。因此，非保守内含子区域的突变增加而不是减少选择性剪接可能是人类疾病发展的重要致病机制。
Frontotemporal dementia accounts for a significant fraction of dementia cases. Frontotemporal dementia with parkinsonism linked to chromosome 17 is associated with either exonic or intronic mutations in the tau gene. This highlights the involvement of aberrant pre-mRNA splicing in the pathogenesis of neurodegenerative disorders. Little is known about the molecular mechanisms of the splicing defects underlying these diseases. To establish a model system for studying the role of pre-mRNA splicing in neurodegenerative diseases, we have constructed a tau minigene that reproduces tau alternative splicing in both cultured cells and in vitro biochemical assays. We demonstrate that mutations in a nonconserved intronic region of the human tau gene lead to increased splicing between exon 10 and exon 11. Systematic biochemical analyses indicate the importance of U1 snRNP and, to a lesser extent, U6 snRNP in differentially recognizing wild-type versus intron mutant tau pre-mRNAs. Gel mobility shift assays with purified U1 snRNP and oligonucleotide-directed RNase H cleavage experiments support the idea that the intronic mutations destabilize a stem-loop structure that sequesters the 5' splice site downstream of exon 10 in tau pre-mRNA, leading to increases in U1 snRNP binding and in splicing between exon 10 and exon 11. Thus, mutations in nonconserved intronic regions that increase rather than decrease alternative splicing can be an important pathogenic mechanism for the development of human diseases.