Transfection of cloned genes into mammalian cells is a powerful tool for biologists to study a specific gene. Many chemicals/methods can be used to introduce foreign DNA into cultured cells including calcium phosphate, DEAE dextran, electroporation and liposomes, with the latter being the most commonly used. There are, however, an abundance of companies selling lipid-based reagents for this purpose, all claiming higher expression and lower toxicity than their competitors. Based on my experience, FuGene® 6 from Promega can live up to those claims with numerous cell lines.
Optimization with FuGene® is a simple process, as the functional ratio of FuGene® to DNA is typically a narrow range for most cells (3:1, 3:2, 6:1 of FuGene®:DNA). The day prior to transfection, cells are seeded at a concentration for 50-80% confluence in 24 h and the process itself is easier and more rapid than for other lipisomal transfection reagents. With most reagents, after incubating the lipid and DNA together, cells are incubated in serum/antibiotic-free media for 4-6 h prior to removal and replacement with complete media. With FuGene®, the complexes are added directly to complete cell culture media (containing FBS) and can be left for days without causing cell damage. The other great feature of FuGene® is its low cellular toxicity. (I have witnessed up to 80% cell death with some cell lines, while the same cell line treated with FuGene® exhibited none.)
With FuGene®, I have obtained excellent transfection efficiency using many cell lines including 293, CHO, HeLa, C6 and HepG2 cells. In addition, the amount of plasmid DNA required is much less than other similar reagents (typically 1 ug per well of 6-well plate, 6 ug per 100 mm dish). Also, the vial of FuGene® has good longevity, as 1 ml of reagent will give over 50 transfections in a 100 mm dish (over 150 for a 6-well plate). Unfortunately, like most lipid-based reagents, FuGene® does not render very high transfection efficiencies. In addition, the website for the FuGene® 6 Cell Line Database is not very useful, as it only lists references and not specific conditions for particular cell lines (the reference normally says “according to manufacturer’s instructions”). Overall, I would recommend FuGene® 6 as a reagent to use for transfecting most cell lines. It is always my first choice with a new cell line before trying other reagents.
Barry Hudson
Research Scientist
Columbia Univerisity
Dept. of Surgery