Figure 1

BIV/MVV Vif affect the synthesis rate of btA3Z2-Z3/oaA3Z2-Z3, respectively, via a proteasomal pathway. (A, B) 293 T cells (0.5 × 10⁶) were transfected with HA-tagged btA3Z2-Z3 (30 ng) or oaA3Z2-Z3 (15 ng) and cmyc-tagged BIV Vif (200 ng) or MVV Vif (200 ng) or VR1012. After 36 h of transfection, the cells were treated with the proteasome inhibitor MG132 (10 μM) (lanes 3, 4) or control DMSO (lanes 1, 2). At 48 h after transfection, the cells were harvested for Western blotting using anti-HA, anti-cmyc and anti-tubulin antibodies. Percentages of degradation with DMSO or MG132 treatment were calculated. (C, D) 293 T cells (0.5 × 10⁶) were transfected with HA-tagged btA3Z2-Z3 (30 ng) or oaA3Z2-Z3 (15 ng) and cmyc-tagged BIV Vif (200 ng) or MVV Vif (200 ng) or VR1012. After 18 h of transfection, the cells were treated with the protein synthesis inhibitor CHX (100 μg/ml) or DMSO as control and then harvested at the indicated time points for Western blot analysis using anti-HA and anti-cmyc antibodies. Percentages of A3 in the presence of Vif relative to that in the absence of Vif with DMSO or MG132 treatment were calculated. All degradation experiments were repeated five times. The mean value ± SEM of the remaining btA3Z2-Z3 precentage after degradation is 18.5 ± 5.2% (P < 0.01); The mean value and SEM of the remaining oaA3Z2-Z3 precentage after degradation is 27.8% ± 6.4% (P < 0.01).