Efficient gene transfer by sequential treatment of mammalian cells with DEAE-dextran and deoxyribonucleic acid.

A variation of the classical DEAE-dextran method of gene transfer was developed for efficient transfection of HeLa cells with plasmid DNA. A brief exposure of the cells to medium containing DEAE-dextran was found to be sufficient for subsequent uptake of pRSVcat and to be superior to cocultivation of the cells with DEAE-dextran plus DNA. This sequential method of gene transfer is nontoxic and yielded up to 60% of HeLa cells positive for a surface protein encoded by the transfected sequence. The implications of this sequential transfection technique regarding the mechanisms of gene transfer are discussed.