The other approach exploits NLS noncovalent binding to plasmid DNA via triple helix formation with an allpurine-NLS oligonucleotide. The chosen 24-mer sequence was shown by PAGE to be stable for 24 h at intracellular K concentrations. Up to eight duplex target sequences were cloned in the pCMV-luc plasmid (Fig. 8). Preliminary transfection data do not show any significant effect of the NLSoligonucleotide.