Insect cells transfected with heterologous DNA can be used to assess the functional properties of genes that have been isolated or subjected to in vitro mutagenesis. An example of such a cell system is embryonic cells derived fromDrosophila melanogaster. These cells can be transfected with special plasmids and used for heterologous protein expression. FISH is an elegant technique for monitoring the transfection efficiency at the single-cell level. The background of this method and the approach used are described here in detail.
