-negative virus fails to efficiently replicate in T-cells. (A) RT-PCR analysis of viral mRNAs taken from Jurkat T-cells that were infected with 10 ng p24gag of wild-type or mutant NL4-3 virus. Total RNA was isolated 6 days post infection and subjected to RT-PCR analysis using different sets of primer pairs (primer positions are shown in Figure 1A). (B) Northern blot analysis of RNAs isolated in (A) using a DIG-labeled HIV-1 exon7 probe detecting all three viral mRNA species. (C) Western blot analysis of intracellular and supernatant HIV-1 Gag collected 6 days post infection as described above. Actin detection was used as loading control.