RYBP and infection: Importantly, we found that the 3xFLAG-RYBP mutant that lacks only the 14-aa RBD still binds to KSHV lytic promoters during de novo infection as efficiently as WT RYBP, which confirms that the interaction of RYBP with PRC1 is not required for its binding to KSHV promoters (Fig 5E–5G).