High efficiency gene transfer by multiple transfection protocol

A high efficiency transfection protocol employing a common polycationic lip id is described. Using LipofectAMINE, a widely used transfection reagent, w e transfected 293T cells with a plasmid harboring the beta-galactosidase (b eta-gal) gene. The transfection efficiency was determined by direct stainin g for X-gal. The conventional transfection protocol achieved an efficiency of < 40% while our protocol, which employs the repetition of transfection a few times, achieved an efficiency of approximately 80%. Thus, a dramatic i ncrease in transfection efficiency can be obtained by simply repeating tran sfection with the use of a common polycationic lipid. This method will be u seful in many molecular biological experiments.