FIG 1.

Polymerase activities of recombinant vRNPs generated from DF-1 cells (A) and kinetics of virus multiplication in DF-1 cells (B and C). (A) Polymerase activities (means ± standard deviations from six or more independent experiments) of recombinant vRNPs in DF-1 cells incubated at 39°C were measured in luciferase reporter assays. The polymerase activity of WB was set at 100% as a reference. Double asterisks indicate P values of <0.01. (B and C) Following infection of DF-1 cells with 0.001 EID₅₀/cell, supernatants were collected at 24 hpi, 48 hpi, and 72 hpi, and viral titers of WB and WB(L/PB1) (B) and of LP and LP(W/PB1) (C) were determined. Data are means ± standard deviations at each time point (n, 3 replicates). Values were analyzed by Welch's t test. Single asterisks indicate P values of <0.05.