Validation of RNA-seq results with qRT-PCR. A 3D4/21 cells were infected with ZJ01 PRV strain at a MOI of 0.5 for 22 h. Relative expression levels of selected lncRNAs were determined by qRT-PCR and normalized to β-actin. B qRT-PCR quantification of the expression levels of lncRNA at three time points (6 h, 12 h, 24 h) after PRV infection. The qRT-PCR was repeated at least three times, with each experiment performed in triplicate. ***P < 0.001; **P < 0.01; *P < 0.05 vs mock control cells for each time point.