Ac4C stabilizes a G-quadruplex to enforce HBV pgRNA clearance
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ABSTRACT: Hepatitis B virus (HBV) pregenomic RNA (pgRNA) is essential for viral replication, but the host factors that degrade it remain poorly understood. Using ac4C-RIP-seq, CLIP-seq, and RedaC:T-amplicon sequencing, we identify an N4-acetylcytidine (ac4C) RNA modification-dependent pathway that targets HBV pgRNA for decay. We find that ac4C modifications, deposited by NAT10, stabilize a G-quadruplex (G4) structure within pgRNA. This ac4C-stabilized G4 structure is recognized and bound by two RNA-binding proteins, hnRNPH1 and GRSF1. hnRNPH1 binding destabilizes the G4 and accelerates pgRNA decay, while GRSF1 directs the RNA to mitochondria for clearance by the RNA degradosome (PNPase/hSUV3). The viral HBx protein upregulates NAT10, forming a negative feedback loop that restricts HBV replication. Together, our findings reveal a multilayered host surveillance mechanism that eliminates viral pgRNA via RNA modification and structural elements. The ac4C-G4-GRSF1 axis represents a potential therapeutic target for HBV cure.
ORGANISM(S): Mus musculus Homo sapiens
PROVIDER: GSE330506 | GEO | 2026/05/13
REPOSITORIES: GEO
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