RECOMBINANT PROTEIN EXPRESSION IN A DROSOPHILA CELL-LINE - COMPARISONWITH THE BACULOVIRUS SYSTEM

In this report, we compare two different expression systems: baculovir us/Sf9 and stable recombinant Drosophila Schneider 2 (S2) cell lines. The construction of a recombinant S2 cell line is simple and quick, an d in batch fermentations the cells have a doubling time of 20 hours un til reaching a plateau density of 20 million cells/ml. Protein express ion is driven by the Drosophila Metallothionein promoter which is tigh tly regulated. When expressed in S2 cells, the extracellular domain of human VCAM, an adhesion molecule, is indistinguishable from the same protein produced by baculovirus-infected Sf9 cells. Additionally, we p resent data on the expression of a seven trans-membrane protein, the d opamine D4 receptor, which has been successfully expressed in both sys tems. The receptor integrates correctly in the S2 membrane, binds [H-3 ]spiperone with high affinity and exhibits pharmacological characteris tics identical to that of the receptor expressed in Sf9 and mammalian eels. The general implications for large scale production of recombina nt proteins are discussed.