Design of carrier peptide-oligonucleotide conjugates with rapid membrane translocation and nuclear localization properties.

Peptides containing a hydrophobic motif associated with a nuclear localization signal separated by various linkers were synthesized in solid phase. The hydrophobic sequence corresponds either to a signal peptide sequence or to a fragment of the fusion peptide of GP41 while the hydrophilic sequence is that of a nuclear localization signal. The C-termini of these peptides bear a cysteamide group that was linked to a fluorescent probe. This allowed the cellular localization of the probe to be determined as a function of the peptide sequences. The labeled peptides were then incubated with fibroblasts. Using N-biotinylated derivatives we confirmed by indirect immunofluorescence that the observed localizations corresponds to those of the peptides. The presence of a linker appears to play a role in the cellular localization. One of these peptides was successfully used to target fluorescent oligodeoxynucleotides into living cells demonstrating improved cell delivery of peptide-oligodeoxynucleotide conjugates.