Fig. 2.
Expression from synthetic promoters using retroviral vectors. a MLV and MSCV-SIN (self-inactivating) vectors depicted as integrated into genome. LTR, retroviral long terminal repeat; PLTR, LTR promoter; PuroR, puromycin resistance gene; PSYN, synthetic promoter derived from CMV or EF1α promoters; PSV40, SV40 promoter; LTR SIN, retroviral long terminal repeat with enhancer sequences deleted; F2A, ribosomal slippagesequence; DEST, recombinase-mediated cloning site; cHS, chicken hypersensitivity site-4. F2A allows bicistronic expression of GFP and a gene of interest inserted in the DEST site. In this study, the mCherry gene was inserted into the DEST site. b Expression by synthetic promoters (GFP fluorescence intensity). c Positive selection of transduced cells: GFP+ fraction after addition of puromycin. MLV (gray bars) and MSCV-SIN (white bars) vectors were evaluated in PD-31 cells. Values are arithmetic means ± s.d. (n = 3) calculated from geometric means of each sample population