title: Dystrophin expression in the mdx mouse after localised and systemic administration of a morpholino antisense oligonucleotide.
abstract: BACKGROUND
  Duchenne and Becker muscular dystrophies are allelic disorders arising from mutations in the dystrophin gene. Duchenne muscular dystrophy is characterised by an absence of functional protein, while Becker muscular dystrophy is usually caused by in-frame deletions allowing synthesis of some functional protein. Treatment options are limited, and we are investigating the potential of transcript manipulation to overcome disease-causing mutations. Antisense oligonucleotides have been used to induce specific exon removal during processing of the dystrophin primary transcript and thereby by-pass protein-truncating mutations. The antisense oligonucleotide chemistry most widely used to alter pre-mRNA processing is 2'-O-methyl-modified bases on a phosphorothioate backbone.
  
  
  METHODS
  The present studies evaluate 2'-O-methylphosphorothioate, peptide nucleic acid and morpholino antisense oligonucleotides in the mdx mouse model of muscular dystrophy, which has a nonsense mutation in exon 23 of the dystrophin gene.
  
  
  RESULTS
  We demonstrate dystrophin expression in mdx mouse tissues after localised and systemic delivery of a morpholino antisense oligonucleotide designed to target the dystrophin exon 23 donor splice site.
  
  
  CONCLUSIONS
  The stability of the morpholino structural type, and the fact that it can be delivered to muscle in the absence of a delivery reagent, render this compound eminently suitable for consideration for therapeutic exon skipping to address dystrophin mutations.
authors.affiliation: Experimental Molecular Medicine Group, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, Perth, Western Australia, 6097. sfletch@cyllene.uwa.edu.au
authors.forename: Susan
authors.initials: S
authors.lastname: Fletcher
authors.forename: Kaite
authors.initials: K
authors.lastname: Honeyman
authors.forename: Abbie M
authors.initials: AM
authors.lastname: Fall
authors.forename: Penny L
authors.initials: PL
authors.lastname: Harding
authors.forename: Russell D
authors.initials: RD
authors.lastname: Johnsen
authors.forename: Steve D
authors.initials: SD
authors.lastname: Wilton
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D018389:Codon, Nonsense; D016189:Dystrophin / Q000096:biosynthesis / Q000235:genetics*; D005091:Exons; D005455:Fluorescent Antibody Technique; D015316:Genetic Therapy; D007273:Injections, Intramuscular; D007274:Injections, Intraperitoneal; D051379:Mice; D018101:Mice, Inbred mdx; D020388:Muscular Dystrophy, Duchenne / Q000628:therapy*; D016376:Oligonucleotides, Antisense / Q000627:therapeutic use*; D022821:RNA Splice Sites
chemical_list: D018389:Codon, Nonsense; D016189:Dystrophin; D016376:Oligonucleotides, Antisense; D022821:RNA Splice Sites