Rescue of dystrophin expression in mdx mouse muscle by RNA/DNA oligonucleotides

Proc Natl Acad Sci U S A. 2000 May 9;97(10):5363-8. doi: 10.1073/pnas.97.10.5363.


Chimeric RNA/DNA oligonucleotides ("chimeraplasts") have been shown to induce single base alterations in genomic DNA both in vitro and in vivo. The mdx mouse strain has a point mutation in the dystrophin gene, the consequence of which is a muscular dystrophy resulting from deficiency of the dystrophin protein in skeletal muscle. To test the feasibility of chimeraplast-mediated gene therapy for muscular dystrophies, we used a chimeraplast (designated "MDX1") designed to correct the point mutation in the dystrophin gene in mdx mice. After direct injection of MDX1 into muscles of mdx mice, immunohistochemical analysis revealed dystrophin-positive fibers clustered around the injection site. Two weeks after single injections into tibialis anterior muscles, the maximum number of dystrophin-positive fibers (approximately 30) in any muscle represented 1-2% of the total number of fibers in that muscle. Ten weeks after single injections, the range of the number of dystrophin-positive fibers was similar to that seen after 2 wk, suggesting that the expression was stable, as would be predicted for a gene-conversion event. Staining with exon-specific antibodies showed that none of these were "revertant fibers." Furthermore, dystrophin from MDX1-injected muscles was full length by immunoblot analysis. No dystrophin was detectable by immunohistochemical or immunoblot analysis after control chimeraplast injections. Finally, reverse transcription-PCR analysis demonstrated the presence of transcripts with the wild-type dystrophin sequence only in mdx muscles injected with MDX1 chimeraplasts. These results provide the foundation for further studies of chimeraplast-mediated gene therapy as a therapeutic approach to muscular dystrophies and other genetic disorders of muscle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Chimera
  • Dystrophin / genetics*
  • Gene Conversion*
  • Gene Expression Regulation / drug effects
  • Genetic Therapy / methods
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred mdx
  • Molecular Sequence Data
  • Muscle Fibers, Skeletal / metabolism
  • Muscle, Skeletal / metabolism*
  • Muscular Dystrophy, Animal / genetics*
  • Muscular Dystrophy, Animal / therapy
  • Oligonucleotides / chemistry
  • Oligonucleotides / pharmacology*
  • Reverse Transcriptase Polymerase Chain Reaction


  • Dystrophin
  • Oligonucleotides