An Epstein-Barr virus-encoded snoRNA directs 2'-O-methylation of human rRNAs to control translation and the viral lytic switch.

Epstein-Barr virus (EBV) establishes life-long latency in human B cells yet the molecular strategies that balance its persistence with lytic replication remain incompletely understood. Here, we identify the EBV-encoded small nucleolar RNA, v-snoRNA1, as a bona fide 2'-O-methylation guide that directs methylation of host ribosomal RNAs at 18S-C621 and 28S-U1760, two conserved residues in the ribosomal A-site. V-snoRNA1-mediated hypermethylation impairs 18S rRNA maturation and compromises translational fidelity and output, resulting in slower cellular proliferation. Infection with a v-snoRNA1 deleted virus (Δv-snoRNA1) leads to enhanced protein synthesis and increased proliferation, together with extensive rewiring of host and viral gene expression. This rewiring includes suppression of immune and interferon pathways and alterations in transcription factor activities important for B cell differentiation. Importantly, we find that v-snoRNA1 is required to facilitate viral production. Our findings reveal a molecular strategy by which EBV directly controls translation to promote infection.