An amphipathic trans -acting phosphorothioate RNA element delivers an uncharged phosphorodiamidate morpholino sequence in mdx mouse myotubes.

An efficient method for the delivery of uncharged polyA-tailed phosphorodiamidate morpholino sequences (PMO) in mammalian cells consists of employing a synthetic 8- mer amphipathic trans -acting poly-2'- O -methyluridylic thiophosphate triester element (2'-OMeUtaPS) as a transfection reagent. Unlike the dTtaPS DNA-based element, this RNA element is potent at delivering polyA-tailed PMO sequences to HeLa pLuc 705 cells or to myotube muscle cells. However, much like dTtaPS, the 2'-OMeUtaPS-mediated internalization of PMO sequences occurs through an energy-dependent mechanism; macropinocytosis appears to be the predominant endocytic pathway used for cellular uptake. The transfected PMO sequences induce alternate splicing of either the pre-mRNA encoding luciferase in HeLa pLuc 705 cells or the excision of exon 23 from the pre-mRNA encoding dystrophin in myotube muscle cells of the mdx mouse model of muscular dystrophy with an efficiency comparable to that of commercial cationic lipid reagents but without detrimental cytotoxicity.
Competing Interests: Conflicts of interest There are no conflicts to declare.