Methods with insect cells in suspension culture. II. Drosophila melanogaster

Drosophila melanogaster cultured cells have been adapted to grow in suspension in a modified mammalian culture medium. This allows labeling of nucleic acids to high specific activity, as well as production of large quantities of relatively homogeneous, logarithmically growing cells. The fact that such an adaptation was possible and that the adapted cells retain a normal Drosophila chromosome complement (although tetraploidy is increased) demonstrates that close adherence of culture medium to the composition of insect hemolymph is probably not necessary once the cell line has been established. Procedures have been developed for fractionation of Drosophila cultured cells into nucleus and cytoplasm in the presence of nuclease inhibitors. Thus, it is possible, despite the high level of endogenous nucleases in these cells, to obtain what appears to be undegraded nuclear and cytoplasmic mRNA. These techniques should be useful for studies of this cell line from the point of view of molecular biology, and hopefully will contribute to the utility of Drosophila as a model system for eukaryotes.