Dystrophin Nonsense Mutations Can Generate Alternative Rescue Transcripts in Lymphocytes
Dystrophin Nonsense Mutations Can Generate Alternative Rescue Transcripts in Lymphocytes
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DOI：
10.1111/j.1469-1809.2008.00468.x
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发表时间：
2008-11-01
影响因子：
1.9
通讯作者：
Matsuo, M.
中科院分区：
文献类型：
--
作者：
Nishiyama, A.;Takeshima, Y.;Matsuo, M.
据报道，剪接的二次改变可以从肌营养不良蛋白基因的几个无义突变中产生半功能性mRNA。外显子剪接增强子被单核苷酸改变破坏被认为是这种改变的基础。然而，这种无意义的依赖突变的剪接改变的精确频率仍然未知。在这里，我们分析了38例由肌营养不良蛋白基因无义突变引起的肌营养不良病患者淋巴细胞中肌营养不良蛋白mRNA的剪接模式。在7例（18%）中，我们观察到无意义编码外显子的部分跳过。然而，7例中有2例表现出无义突变产生的剪接位点的复杂激活，这导致了新转录本的产生。通过计算剪接概率得分和鉴定潜在剪接增强子或沉默子序列来检查顺式调节剪接元件未能揭示外显子跳变的单一原因。值得注意的是，在具有相同无义突变（C.5899C . > T）的患者的细胞中，观察到剪接模式的个体差异。虽然5例产生半功能性肌营养不良蛋白mrna，但其中只有1例表现出轻微的临床病程。这些结果为候选反义寡核苷酸诱导外显子跳变的靶点和无义突变的核糖体读通提供了重要的见解。
Secondary alterations in splicing have been reported to produce semi-functional mRNA from several nonsense mutations in the dystrophin gene. Disruptions of exonic splicing enhancers by single nucleotide changes are thought to underlie such alterations. The precise frequencies of such nonsense mutation-dependent splicing alterations, however, remain unknown. Here we analyzed the splicing patterns of dystrophin mRNA in lymphocytes from 38 patients with dystrophinopathies due to nonsense mutations in the dystrophin gene. In seven of the cases (18%), we observed partial skipping of the nonsense-encoding exon. Two of the seven cases, however, exhibited complex activation of a nonsense mutation-created splice site, which resulted in the generation of novel transcripts. Examination of cis-regulatory splicing elements through calculation of splicing probability scores and identification of potential splicing enhancer or silencer sequences failed to disclose a single cause for exon skipping. Remarkably, individual differences in splicing patterns were observed for cells from patients with identical nonsense mutations (C.5899C > T). Although five cases produced semi-functional dystrophin mRNAs, only one of these exhibited a mild clinical course. These results provide important insights about targets for exon skipping induced by candidate antisense oligonucleotides and for ribosomal read-through of nonsense mutations.