Protein expression in Drosophila Schneider cells

We expressed recombinant secreted, membrane, and cytosolic proteins in stab ly transfected Drosophila Schneider (SL-3) cells. To allow easy cloning of N- and C-terminal fusion proteins containing epitope- and His-tags for the detection of recombinant proteins and purification by affinity chromatograp hy we constructed new expression vectors. To exemplify the general applicab ility of protein expression in Schneider cells we characterized the express ion system with respect to inducibility, localization of the recombinant pr oteins, yields of purified proteins, and presence of posttranslational and cotranslational modifications. Secreted proteins became quantitatively N-gl ycosylated in SL-3 cells and the N-glycan of a Gels-resident membrane prote in was found to be Endo-H-resistant. Myristoylation of AnxXIIIb, a member o f the annexin family, could be demonstrated and glycosylphosphatidylinosito l-anchored proteins containing their lipid anchor were expressed efficientl y in SL-3 cells. Since generation of stable cell lines and mass culture of SL-3 cells is cheap and easy, they provide an attractive eukaryotic express ion system. (C) 2000 Academic Press.