Schematic representation of the genomes of the lentiviral vectors generated.The parent vector was CMV-EGFP-SIN. This vector has a 400-bp deletion in the U3 region of the LTR to inactive transcription from the lentiviral promoter. Ψrepresents the packaging signal for the vectors. The restriction enzyme sites used to generate the other vectors are marked by vertical arrows and labeled. The 2 horizontal arrows represent hybridization sites for 2 PCR primers used to detect the presence of integrands using total genomic DNA. In vector IEKIgP-EGFP-SIN, the orientation of the enhancers (IEK) is the reverse of that in KIE. R indicates repeat and P indicates immunoglobulin promoter. Gray boxes indicate EGFP.