FIG. 1.

Schematic diagrams of lentivirus vectors SMPU-18x21-EGFP and SMPU-E-sel-EGFP. In the SMPU vectors, the majority of the human immunodeficiency virus gag coding region and the complete coding region for pol, env, and accessory genes have been removed. The 5′ U3 region is replaced by the CMV enhancer/promoter, and a deletion is made in the 3′ U3 region (ΔU3 R). The reporter gene to be transduced, the EGFP gene in this case, is driven by the 18x21 (A) or E-selectin (E-sel) promoter cassette (B). Upon introduction of the reporter vector into a target cell, the U5 region in the 5′ LTR and the ΔU3 region in the 3′ LTR of the vector mRNA are duplicated through reverse transcription. The only functional enhancer/promoter element in the integrated DNA is the Tax-responsive 18x21 promoter or the E-sel promoter.