Gene Transfer in Vascular Cells Using an Engineered Na-H Exchanger (NHE1) as a Selectable Marker

The techniques of gene transfer using transfection via electroporation, CaPO₄ , or cationic lipids rely on selectable markers because of the low efficiency of this approach. Selectable markers range from fluorescent molecules to a variety of cytotoxic compounds, with the most commonly used in animal cells being neomycin, hygromycin, and gancyclovir. With fluorescent molecules or cell surface markers that can be visualized with fluorescent antibodies, one needs a cell sorting machine, whereas with cytotoxic drugs, the procedure is simpler, but requires several days to irradicate the majority of the cell population that has not received the gene of interest. In the case of vascular cells (smooth muscle or endothelial cells), the nontransfected population could easily exceed 90% of the total cell population.