Fig. 3.

Comparison of expression from synthetic variants of the CMV promoter in different cell lines and vectors. Expression levels (GFP fluorescence intensity) from MLV (left) and MSCV-SIN (right) vectors in PD-31, NIH/3T3, and HeLa cells compared against those from plasmid vector expression in HEK-293 cells. Fit to linear regression (dashed line; y = 1.223x for PD-31, y = 1.141x for NIH/3T3, and y = 1.000x for HeLa) indicates whether relative promoter strengths were maintained between different cell types. Values are arithmetic means ± s.d. (n = 3 for PD-31, HEK-293 Flp-In and n = 2 for NIH/3T3, HeLa) calculated from geometric means of each sample population