After infection with the PRRSV SX-1 strain, PSF and P54 protein expression was upregulated (Fig. 2A), and the antisense pathway was the most variable of all the significant signaling pathways for the highly virulent SX-1 strain; however, this finding was not observed in the signaling pathways for the moderately virulent ZCYZ strain or the mildly virulent SD1 strain (Fig. 2A). This evidence concerns the gene NONO and infection.