Department of Neurology, University of Rochester Medical Center, Rochester, New York 14642, USA.
Mol Ther. 2013 Feb;21(2):380-7. doi: 10.1038/mt.2012.222. Epub 2012 Nov 27.
Myotonic dystrophy type 1 (DM1) is an RNA dominant disease caused by expression of DM protein kinase (DMPK) transcripts that contain an expanded CUG repeat (CUG(exp)). The toxic mRNA localizes to nuclear foci and sequesters proteins involved in the regulation of alternative splicing, such as, muscleblind-like 1 (MBNL1). Here, we used synthetic short interfering RNAs (siRNAs) to target CUG repeats and test the concept that inhibiting the expression of CUG(exp) RNA can mitigate features of DM1 in transgenic mice. Intramuscular injection and electroporation of siRNA resulted in ~70-80% downregulation of CUG(exp) transcripts. A limited survey of endogenous mouse transcripts that contain nonexpanded CUG or CAG repeats showed that most were not affected, though Txlnb containing (CUG)(9) was significantly reduced. By this strategy, the number and intensity of CUG(exp) nuclear foci were reduced and splicing of MBNL1-dependent exons was improved. These data suggest that the expanded CUG repeats are a potential target for allele-selective RNA interference.
肌强直性营养不良 1 型（DM1）是一种 RNA 显性疾病，由含有扩展的 CUG 重复（CUG(exp)）的 DM 蛋白激酶（DMPK）转录本表达引起。毒性 mRNA 定位于核灶中，并隔离参与可变剪接调节的蛋白质，例如肌肉盲样蛋白 1（MBNL1）。在这里，我们使用合成的短干扰 RNA（siRNA）靶向 CUG 重复，并测试抑制 CUG(exp)RNA 表达是否可以减轻转基因小鼠中 DM1 的特征的概念。siRNA 的肌内注射和电穿孔导致 CUG(exp)转录本的下调约 70-80%。对包含非扩展 CUG 或 CAG 重复的内源性小鼠转录本进行的有限调查表明，大多数转录本不受影响，尽管包含（CUG）(9)的 Txlnb 显著减少。通过这种策略，CUG(exp)核灶的数量和强度减少，并且 MBNL1 依赖性外显子的剪接得到改善。这些数据表明，扩展的 CUG 重复是等位基因选择性 RNA 干扰的潜在靶标。
