Figure 4

Schematic and viral titer of different lentiviral vector packaging constructs. Lentiviral vectors were produced using different transfer plasmids containing RRE (Fig. 4A) or multiple copies of SRV-1 (Fig. 4B) or MPV CTE (Fig. 4C). Viral titer was determined by end-point dilution using X-gal stained HeLa cells and p24 Gag protein ELISA. HATCHED bars = Kozak sequence (CCACCATGG); W = woodchuck post-regulatory element; C = constitutive transport element; pA = bovine growth hormone poly(A) signal; RRE = rev-responsive element; SD = splice donor; SA = splice acceptor. * p < 0.05 difference between lentiviral vectors produced with or without the rev protein.