Jacobs Journal of Genetics

A Short Morpholino CAG15 Corrects Aberrant Alternative Splicing of Clcn1 and Serca1 In Vivo

Published on: 2018-08-28

Abstract

Myotonic dystrophy type 1 (DM1) is a hereditary disease associated with multisystemic disorders including myotonia, muscle weakness, and cataracts. DM1 cells express DMPK mRNA harboring expanded CUG repeats, which are responsible for sequestering MBNL1, an RNA-binding protein. MBNL1 regulates alternative splicing of several genes, and sequestration of MBNL1 in the nucleus possibly causes DM-specific symptoms such as myotonia. Therefore, it has been suggested that blocking the interaction between MBNL1 and the RNA CUG repeats would be a promising therapeutic strategy for DM1. A CAG-repeat morpholino oligonucleotide (MO) is expected to bind to expanded CUG repeats in RNA, thus preventing MBNL1 sequestration. In the present report, we optimized the lengths of relevant MOs. We introduced 15-mer, 20-mer, and 25-mer MOs into Neuro 2a cells, which express CUG repeat-containing RNA. We also injected MOs into mice with DM1 (the HSALR line). Such work showed that the 15-mer MO most effectively corrected aberrant splicing of Clcn1 and Serca1. To increase MO permeability, a 15-mer vivo-MO was administered intravenously and resulted in corrected aberrant Clcn1 splicing in the quadriceps of HSALR mice. These results suggest that the short 15-mer MO most efficiently corrects aberrant splicing.

Keywords

Myotonic dystrophy (DM1); Antisense; Clcn1; Serca1; Alternative Splicing