(A) Plaque formation of MP-12, scMP-12 and VRP in Vero-G cells. Vero-G cells were infected with MP-12, scMP-12, or VRP and overlaid with medium containing Tragacanth gum. After fixing the cells, plaques were stained with anti-N antibody and visualized using a Nova RED peroxidase substrate. (B) Growth kinetics of scMP-12, MP-12, and VRP in Vero-G cells. Vero-G cells were infected with scMP-12, MP-12, and VRP at an MOI of 0.05 and viral titers at 24, 48, 72, and 96 h p.i. were determined by plaque assay in Vero-G cells. The data are reported as mean titers with standard deviations of three independent experiments. (C) Vero-G cells were infected with MP-12, scMP-12, and VRP at an MOI of 0.05. Intracellular RNAs were harvested at 16 h p.i. and subjected to Northern blot analysis using RNA probes which hybridized with viral-sense L, M, or S RNA. (D) Vero-G cells were infected with MP-12, scMP-12, or VRP at an MOI of 0.02, and culture fluid was collected at 3 days p.i. The released particles were purified by sucrose gradient centrifugation and subjected to Western blot analysis using anti-MP-12 antibody (left panel). RNA samples corresponding to the samples in the left panel were subjected to Northern blot analysis using RNA probes that hybridized with viral-sense L, M, or S RNA (right panel).