MX1 and Zika virus infectious disease: In contrast to ZIKV infection in ATF3 KO cells, poly I:C and IFN-β treatment of ATF3 KO cells activated JAK/STAT signaling, increased the transcript levels of STAT1, IFIT1, and MX1 (Fig. 7A through C and E through G), and led to the expression of downstream IFN-induced proteins (Fig. 7D and H).