An engineered viral RNA degrader on mitochondrial surface that mitigates RNA virus infection

Infections by RNA viruses cause diseases. Host factor(s) that restrain viral propagation offer new anti-virus strategies. We use vesicular stomatitis virus (VSV) as a model and observe the synthesis of VSV RNAs at mitochondria/endoplasmic reticulum (Mito/ER) spheres, accompanied by the leakage of endonuclease G (ENDOG), a mitochondrial nuclease, to the cytosol. We provide evidence that ENDOG released from mitochondria is a host anti-viral factor by eliminating viral RNAs for replication. However, ENDOG outside mitochondria can translocate to nuclei and cause nuclear DNA damages. We engineer an ENDOG expressed on mitochondrial outer membrane (MOM), namely MOM-ENDOG, to increase the accessibility to viral RNA transcripts synthesized at mitochondrial sites without damaging nuclear DNA (nDNA). Delivery of modified mRNA of wild-type but not catalytic-dead MOM-ENDOG markedly suppresses not only the propagation of VSV, but also Dengue and Zika virus. Thus, this organelle-specific viral RNA degrader may be developed as a broad-spectrum anti-viral agent.