Reverse transcriptase PCR analyses of gene expression from lentiviral vector NL-GFP-RRE-(SA) in response to HIV-1 infection. (A) A diagram of PCR primers used. Two sets of primers were used to detect the spliced (black arrows) and unspliced (green arrows) transcripts by reverse transcriptase PCR (RT-PCR) as described in Methods. The mRNA molecules from infected and uninfected cells were extracted at day 3 after lentiviral vector infection and analyzed by RT-PCR for the spliced transcripts and unspliced transcripts as shown in (B). (B) CEM-SS cells were either uninfected (lane 1, control), infected with HIV alone (lane 2, HIV, VSV-G pseudo-typed, 564 ng p24 per million cells), infected with NL-GFP-RRE-(SA) alone (lane 3, 1764 ng p24 virion per million cells), or infected with HIV first, then NL-GPF-RRE(SA) 24 hours later (lane 4). The cellular β-actin transcript was also amplified to ensure that comparable numbers of cells were used for the analyses.