Figure 1.

Plant viral RSS protein NS3 complements HIV-1 Tat. (A) Lysates of human embryonic kidney (HEK) 293T cells, transfected with expression plasmids for GFP, MBP-NS3, MBP-NS3m or MBP (900 ng), were analysed for protein expression by Western blot analysis, using a rabbit polyclonal antiserum against MBP. Immunological detection of β-actin acted as a loading control. (B) HEK293T cells were co-transfected with HIV-rtTA-Tat^wt and HIV-rtTA-Tat^fs (100 ng) in combination with increasing amounts (10, 100, 600 and 900 ng) of NS3 or Tat expression plasmids. The vector expressing MBP (900 ng) was used as a negative control. The production of HIV-1 was determined 2 days post-transfection by detecting CA-p24 in the supernatant using ELISA. The mean of at least three independent experiments is shown with standard error. ELISA, enzyme-linked immunosorbent assay; GFP, green fluorescence protein; HIV-1, human immunodeficiency virus type 1; MBP, maltose-binding protein; NS3, non-structural protein 3; NS3m, mutant protein; RSS, RNA silencing suppressor; Tat, transactivator of transcription.