Fig. 2
Activities of chimeric pBS-BFV clones. a The BFV3026 proviral genome is shown at the top. The gray box depicts the BFV3026 proviral genomic DNA of pBS-BFV-Y, and the white box represents that of pBS-BFV-B. The full-length viral DNA was divided into three segments, S1, S2 and S3, based on the single restriction enzyme sites of EcoR I and Nde I. The new chimeric clones were generated by exchanging the fragments between pBS-BFV-Y and pBS-BFV-B plasmids. b-c BHK-21 cells (1.2 × 105) were transfected with 1 μg pBS, pBS-BFV-B, pBS-BFV-Y or different chimeric mutants as indicated. At 48 h post-transfection, cells were harvested and co-cultured with BFVL cells b. Transfected BHK-21 cells were also analyzed by Western blotting to measure viral protein expression c. d Cf2Th cells (1.5 × 105) were transfected with 2.5 μg pBS, pBS-BFV-B, pBS-BFV-Y or different chimeric mutants as indicated. Seventy-two hours later, syncytia (white arrows) were recorded using a microscope