High-efficiency polyethylene glycol-mediated transformation of mammalian cells

A new, high-efficiency method for transformation of mammalian cells with nucleic acids is described which yields 10(5)-10(6) plaques/micrograms poliovirus infectious RNA (iRNA). The optimized procedure consists of two steps: (1) exposure of cells to iRNA in a high ionic-strength buffer followed by (2) a brief exposure to a 35% polyethylene glycol (PEG) solution. Optimized conditions for each variable in the procedure are described. Under optimized conditions for PEG-mediated transformation with RNA, large numbers of transformants are recovered with plasmid DNA as well. The procedure presented is similar to other high-efficiency PEG-mediated methods previously described for the genetic transformation of both nonprotoplasted Escherichia coli and yeast.