FIG 4.

eIF4A is required for efficient PSaV replication in cell culture. (A) PSaV infectivity was determined by 50% tissue culture infective dose (TCID₅₀) after treatment with MeSO₄ or increasing concentrations of hippuristanol. (B) Transfection with either control or eIF4AI small interfering RNAs (siRNAs) was performed in LLC-PK cells. Decreased eIF4AI protein expression was verified by Western blotting prior to PSaV infection. (C) PSaV mRNA was quantitated by qPCR after control or eIF4AI siRNA transfection. (D) The levels of infectious virus were determined by titer by TCID₅₀. Samples were analyzed in triplicate in three independent experiments. Error bars represent the means ± SEM from triplicate samples: *, P < 0.05; ***, P < 0.0001. The dashed line is used to indicate the limit of detection by TCID₅₀.