Electroporation of mammalian cells with a firefly luciferase expression plasmid: kinetics of transient expression differ markedly among cell types.

Electroporation in combination with the luciferase reporter system provides a rapid and sensitive means of determining transient expression from plasmid constructs in various mammalian cells. Conditions are described allowing efficient electroporation of several cell types with a commercial electroporation device. Measurements on extracts prepared at various times after electroporation showed a rapid rise in luciferase activity for up to 12 hr, which was followed, in certain cell types, by a rapid decline. With such cells, determinations made after 48-72 hr, as is conventional, would greatly underestimate expression of the luciferase reporter gene. Therefore, to observe optimum activity, the kinetics of expression must be determined for each cell type.