CDK9 and infection: However, different from its homologs in HSV-1, there is no interaction between HEXIM1 or CDK9 with AnHV-1 US1, neither by infection with AnHV-1 US1-3*HA nor by transfection with the pCAGGS US1-3*Flag plasmid (Fig. 7F and G), Despite this, another phenomenon worth noting was that US1 and RNAPII S2P could interact with each other at the viral infection level but not at the plasmid transfection level, suggesting that the interaction between US1 and RNAPII S2P requires the participation of other viral proteins.