The pIEx/Bac? vectors are dual-purpose vectors that offer unique flexibility for cloning and expression of proteins in Spodoptera-derived insect cells. These vectors contain the Autographa californica nuclear polyhedrosis virus (AcNPV) enhancer/immediate early promoter combination (hr5/ie1) for plasmid-mediated and early baculovirus expression, and the AcNPV p10 very late promoter for robust baculovirus-mediated expression. All pIEx/Bac plasmids carry AcNPV-derived virus regions to mediate recombination at the polh locus. The pIEx/Bac-3 vector contains an N-terminal His?Tag? coding sequence with 10 histidines followed by an HRV 3C protease cleavage site and a multiple cloning site, with the option to include a C-terminal thrombin protease cleavage site and 8 aa Strep?Tag? II coding sequence. pIEx/Bac-3 is also available as a 3C/LIC vector. The 3C/LIC vector is prepared for rapid directional cloning of PCR-amplified DNA. Using specifically designed primers for amplification, inserts can be efficiently cloned without the need for restriction enzyme digestion or ligation.