Drosophila RNA polymerase II recognizes invading viral DNA to initiate antiviral responses

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A new publication (https://doi.org/10.1016/j.celrep.2022.110976) in Cell Reports provides new insights into how DNA viruses are recognized by the innate immune system in insects..

Viruses are obligatory intracellular parasites that hijack the host cell machinery. Host cells need to rapidly recognize the infection and initiate effector antiviral defenses to prevent viral replication. Double stranded RNA (dsRNA) is a hallmark of viral infections and a potent activator of antiviral defenses in eukaryotic cells. During RNA virus infections dsRNA is generated as a byproduct of genome replication but, in the case of DNA viruses, its origins are less clear. In a study published in Cell Reports, the researchers describe a defense mechanism in which the host cell converts invading viral DNA into dsRNA in order to mount an antiviral response in the model organism Drosophila melanogaster

Convergent evolution of the role of different RNA polymerases (RNAP) that convert viral DNA into dsRNA to activate antiviral defenses. In Drosophila, RNAPII recognizes viral DNA in the nucleus and generates long dsRNAs that activate Dicer-2 (left). In mammals, cytoplasmic RNAPIII converts AT-rich DNA into short dsRNAs with a triphosphate at the 5’that activate RIG-I (right).

12 August 2022

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