Figure 6

The Bel1 domain and the C-terminal 22 amino acids of FFVBet can be replaced by PFV Bet sequences without loss of function. HEK293T cells were cotransfected with 4 μg pCF-BBtr, 0.8 μg pcDNA or pfeA3Z2b, and 6 μg of plasmid expressing wt FFV Bet, PFV Bet or chimera, as indicated in the picture. (A, C) Two d.p.t., titration was performed and viral titers are represented as mean values of three independent experiments. Error bars represent standard deviations. In the presence of feA3Z2b, the FFV-BBtr titer decreased more than two logs. Unlike FFV Bet, which completely rescued titers, PFV Bet did not counteract feA3Z2b activity. Chimera CH1, 2, 3, and 11 completely restored the viral titer in the presence of feA3Z2b (indicated by the line above the graphs). (B, D) FFV Bet and chimeric Bet were detected with anti-V5 IgG while PFV Bet was detected with a PFV Bet-specific serum. Anti-HA IgG was used for feA3Z2b-HA detection, rabbit anti-matrix serum for Gag detection, and anti-β-actin IgG as a loading control.