Bugs Are Not to Be Silenced: Small RNA Pathways and Antiviral Responses in Insects

Like every other organism on Earth, insects are infected with viruses, and they rely on RNA interference (RNAi) mechanisms to circumvent viral infections. A remarkable characteristic of RNAi is that it is both broadly acting, because it is triggered by double-stranded RNA molecules derived from virtually any virus, and extremely specific, because it targets only the particular viral sequence that initiated the process. Reviews covering the different facets of the RNAi antiviral immune response in insects have been published elsewhere. In this review, we build a framework to guide future investigation. We focus on the remaining questions and avenues of research that need to be addressed to move the field forward, including issues such as the activity of viral suppressors of RNAi, comparative genomics, the development of detailed maps of the subcellular localization of viral replication complexes with the RNAi machinery, and the regulation of the antiviral RNAi response.