[HTML][HTML] RNA interference targeting CUG repeats in a mouse model of myotonic dystrophy

K Sobczak, TM Wheeler, W Wang, CA Thornton - Molecular Therapy, 2013 - cell.com
K Sobczak, TM Wheeler, W Wang, CA Thornton
Molecular Therapy, 2013cell.com
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 …
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 (CUGexp). 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 CUGexp RNA can mitigate features of DM1 in transgenic mice. Intramuscular injection and electroporation of siRNA resulted in ~70–80% downregulation of CUGexp 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 CUGexp 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.
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