Figure 1.

MPG-mediated gene delivery in the presence of inhibitors of the endosomal pathway. (A) MPG/DNA complexes formed at a charge ratio of 5:1 with 100 ng pRL-SV40 plasmid encoding the reporter gene luciferase were overlaid onto human fibroblasts (HS-68) in the presence of either bafilomycin A (Baf-A, 150 nM), cytochalasin B (Cy-B, 50 µg/ml) or chloroquine (Chl, 100 µM). After 48 h cell extracts were prepared and luciferase activity was measured and reported as a function of total protein (black). Similar experiments were performed using a lipid-based delivery system, Lipofectamine™, as a control (white). Experiments in the absence of inhibitors were also performed using an MPG peptide lacking a C-terminal cysteamide group (grey). (B) A fluorescein-labelled 36mer oligonucleotide was complexed with MPG at a charge ratio of 5:1. Complexes were then overlaid onto cultured HeLa cells in the presence of bafilomycin A (middle panel) or cytochalasin B (bottom panel) and cellular localisation of the oligonucleotide was monitored by fluorescence microscopy on living cells 1 h after transfection. A control experiment with free oligonucleotide is shown in the top panel.