ABSTRACT
The most commonly used method to introduce DNA directly into a tissue employs a conventional needle and syringe. Receptor-mediated gene delivery is probably the most promising non-viral delivery technique for gene therapy, considering its combination of high transfection efficiency, tissue-specific targeting, and presumably limited immunogenicity. Tissue-specific expression of genes is controlled by promoter and enhancer elements. The approaches that have been taken are generally based on considerations of endogenous cellular mechanisms of targeting as well as those employed by infectious microorganisms. The precise mechanism by which some DNA escapes this degradative pathway and results in gene expression is currently not well understood. Most of the cell-surface proteins which have so far been selected for receptor-mediated gene delivery have been actively recycling receptors that associate with coated pits. Delivering DNA which will persist in cells raises many safety issues but it may be necessary to correct certain types of genetic diseases.
