PPP1R15A and infection: Following infection, P-eIF2α initiates the transcription of ATF4, which then upregulates the expression of UPR-associated genes, including PPP1R15A and an inducer of apoptosis called CHOP. Our study detected upregulation of ATF4 in the medium and high dose groups, which further affirms the apoptosis in ASFV pathogenesis.