Pseudouridine prevalence in Kaposi's sarcoma associated herpesvirus transcriptome reveals an essential mechanism for viral replication

Pseudouridylation is a prevalent RNA modification shown to occur in tRNAs, rRNAs, snoRNAs and most recently mRNAs and lncRNAs. Emerging evidence suggests that this dynamic RNA modification is implicated in altering gene expression by regulating RNA stability, modulating translation elongation and modifying amino acid substitution rates. However, the role of pseudouridylation in infection is poorly understood. Here we demonstrate that Kaposis sarcoma-associated herpesvirus (KSHV) manipulates the pseudouridylation pathway to enhance replication. We show the pseudouridine synthases (PUS), PUS1 and PUS7 are essential for efficient KSHV lytic replication, supported by the redistribution of both PUS1 and PUS7 to viral replication and transcription complexes. We present a comprehensive analysis of KSHV RNA pseudouridylation, revealing hundreds of modified RNAs at single-nucleotide resolution. Notably, we further demonstrate that pseudouridylation of the KSHV-encoded polyadenylated nuclear RNA (PAN) plays a significant role in the stability of PAN RNA and in the association of the KSHV ORF57 protein. Our findings reveal a novel and essential role of pseudouridine modification in the KSHV replication cycle.