Fuente: WIPO "tomato" Provided herein are fusion proteins having a sensor domain that binds double-stranded nucleic acids, and an effector domain that cleaves RNA. The fusion proteins are surprising effective in inhibiting the replication of a broad variety of viruses. The fusion proteins are designed to have effector domains of particular sequence lengths, thereby improving the antiviral activity of the fusion protein. Also provided are nucleic acids encoding the fusion proteins; vectors, cells, multicellular organisms including the fusion proteins; and treatment methods using the fusion proteins.