AO induced excision of human dystrophin exon 20. Primary human myogenic cultures were transfected with cationic lipoplexes:AO preparations at the concentrations indicated and incubated for 24 hours before total RNA was extracted. Nested RT-PCR was undertaken across exons 18–26. The full-length and exon 20 deleted transcripts are represented by products of 1336 and 1094 bp, respectively. (a) Overview of AO annealing coordinates across dystrophin exon 20. (b) AO cocktail 20.1 and 20.2, (c) AO cocktail 20.1 and 20.3, (d) AO cocktail 20.2 and 20.5, (e) AO cocktail 20.3 and 20.4, (f) AO cocktail 20.5 and 20.6, (g) single AO 20.6.