PRC1 and Zika virus infectious disease: As examples of transcriptional regulation, CBX4, a member of Polycomb group (PcG) multiprotein PRC1-like complex and inhibiting expression of many genes [53–55], and HEY1, a transcriptional repressor binding preferentially to the canonical E box sequence 5-CACGTG-3 [56], were also upregulated both at gene and ISO expression levels for about 2.5 folds after ZIKV infection (Fig. 4h).