Figure 2.

Schematic overview of the pQL13 vector system and the FlpIn™ T-REx™ stable cell lines.In pQL13, Env expression is linked to eGFP expression by a TaV 2A peptide. The eGFP-Env expression cassette is integrated into a distinct Flp Recombination Target (FRT) site within the FlpIn™ T-REx™ HEK293 cells, providing the hygromycin gene with a start-codon and hence resulting in the acquisition of a hygromycin resistance that can be used for selection of stable cell lines. Expression of eGFP and Env is under regulation of the Tet repressor (TR, T-REx™, red triangle) and thus inducible. The locations of the TaV 2A peptide, as well as the ATG leading to the acquisition of the hygromycin resistance, are highlighted in red. Note that the pQL13 vector graphic shows the horizontal map of the circular QL13 plasmid and that the FRT site (52 bp) and the Tet operator sequence (TO, 9 bp, clear diamond) are not in scale in this schematic. P: Promotor (SV40: simian virus 40, CMV: cytomegalovirus, BLA: β-lactamase), lacZ: β-galactosidase ORF, Amp: ampicillin ORF, Hyg: hygromycin ORF, ori: origin of replication, TR: Tet repressor protein, TaVp2A: TaV 2A peptide. Promotor positions are indicated by bent arrows.