Transposable Elements and viral immunity

All genomes contain genomic parasites called transposable elements (TEs), some of which resemble viruses. TEs are controlled by small RNAs of the piRNA class, and viruses are fought against by small RNAs of the siRNA class. Considering these similarities in structure and control pathways between TEs and viruses, reciprocal impacts of TE control and antiviral immunity are suspected. Indeed, in a Drosophila system, upon viral infection, TE transcript amounts are modulated, as well as their controlling small RNAs. Altogether, these data demonstrate an impact of viral infection on TE control, likely mediated by RNAi pathway in Drosophila.