Figure 1. Schematic representation of lentiviral plasmids used in this study.

A) The numbers in parentheses at the top designated as pLenti/EGFP indicate each region of viral sequence elements residing in the 5′ UTR of HIV-1 according to the genome sequence of HXB2 isolate [19]. Shown below is an enlargement of the 5′ UTR region and its nucleotide sequence. Black triangles around the packaging sequence Psi indicate nucleotide positions in which restriction enzyme sites were created to generate lentiviral transgene vectors used in this study. Open triangles indicate each nucleotide positions to generate serial deletion mutants of the Psi tested in this study, which are also schematically shown in Figure 6A. B) Nucleotide positions and sequence changes introduced in the transgene vector constructs are indicated.