FIG 6.

Small-molecule inhibitors PF74 and BI-2 prevent the binding of Nups containing FG repeats to the HIV-1 capsid. (A) HIV-1 viruses bearing changes on residue N57 are resistant to the inhibitory effects of PF74 and BI-2. Human HT1080 cells were challenged with the indicated HIV-1-GFP viruses in the presence of increasing concentrations of PF74 or BI-2. Infection was determined by measuring the percentage of GFP-positive cells 48 h postinfection. The percentage of infection relative to that of untreated samples is shown. Similar experiments were performed using human HeLa (B), dog Cf2Th (C), and human Jurkat (D) as target cells. (E) Binding of Nups to HIV-1 capsid is inhibited by PF74 and BI-2. The ability of the indicated Nups to bind in vitro-assembled HIV-1 CA-NC complexes in the presence of PF74 or BI-2 was measured as described in Materials and Methods. As a specificity control, we tested the ability of TRIMCyp to bind in vitro-assembled HIV-1 CA-NC complexes in the presence of PF74, BI-2, or cyclosporine (CsA). INPUT and BOUND fractions were analyzed by Western blotting using anti-GFP, anti-FLAG, or anti-p24 antibodies. As a positive control, we measured the ability of CPSF6 to bind in vitro-assembled HIV-1 CA-NC complexes in the presence of PF74 or BI-2. Results were analyzed using two-tailed Student's t test. Differences were considered statistically significant at a P value of <0.05 (*), <0.01 (**), <0.001 (***), or <0.0001 (****) or were nonsignificant (ns).