Fig. 4

In vitro optimization and validation of the dual reporter system. A: Schematic representation of the experimental setup and the lentiviral dual reporter expression constructs. Luciferase and eGFP are expressed under either hPCK, CMV or EF1α promoter. B: In vitro luciferase assay, displayed in pseudo-colour. C: Scatter plot including linear regression showing the relation between bioluminescence signal (rel. units) and detection time, virus amount and D-luciferin concentration. D: Luminescence assay showing the luminescence signal in HEK cells (left) and NPCs (right), depending on the used promoter. E: Fluorescence images of transduced NPCs. The rectangle shows an enlarged section as shown on the right. F: Flow cytometry of GFP + cells in non-transduced (left plot) and transduced cells (right plot). Quantification of GFP + cells (right graph). Boxplots indicate the 25–75% quartiles of the data. Each dot in the plots represents one cell culture well and significance of mean differences between the groups was assessed using Tukey’s HSD. Asterisks indicate significance: *** p < 0.001. rfLuc: red firefly luciferase; hPGK: human phosphoglyceratkinase; CMV: cytomegalovirus; EF1α: elongation factor 1; scale bar: 10 µm; Line graphs are plotted as mean.