EPAS1 and infection: At 6 h after infection, two subclasses of transcription factors predominated: 1) transcription factors associated with cellular stress-responses including TP53 (p53), EPAS1, HIF1A and NFE2L2 (Nrf2); and 2) transcriptional regulators associated with the antiviral program including IRF1/3/7, STAT1/ISGF3 and NF-κB complex (Fig. 2D).