Viral infection impacts transposable element transcript amounts in Drosophila

Transposable elements (TEs) are genomic parasites that are found in all genomes, some of which display sequence similarity to certain viruses. In insects, TEs are controlled by the Piwi-interacting small interfering RNA (piRNA) pathway in gonads, while the small interfering RNA (siRNA) pathway is dedicated to TE somatic control and defense against viruses. So far, these two small interfering RNA pathways are considered to involve distinct molecular effectors and are described as independent. Using Sindbis virus (SINV) in Drosophila, here we show that viral infections affect TE transcript amounts via modulations of the piRNA and siRNA repertoires, with the clearest effects in somatic tissues. These results suggest that viral acute or chronic infections may impact TE activity and, thus, the tempo of genetic diversification. In addition, these results deserve further evolutionary considerations regarding potential benefits to the host, the virus, or the TEs.

Viral infection impacts transposable element transcript amounts in Drosophila

This research article published in PNAS on June 2020 shows some of the data obtained by Dr Marlène Roy during her thesis that has been co-directed by Dr Marie Fablet (Univ Lyon, LBBE) and Maxime Ratinier (PSL-EPHE, IVPC). Marlène shows that Sindbis virus infection impacts Transposable Elements (TE) transcript amounts within Drosophila somatic tissues as well as TE-derived small RNA amounts in Drosophila ovaries. We believe that this work offers new avenues to investigate the role of viral infection in insect’s genetic diversification.

The  ERMIT (Endogenous Retroviruses and iMmunITy) project was supported by the Laboratory of Excellence (LabEx) Ecofect (Eco-evolutionary dynamics of infectious diseases) that promotes interdisciplinary research involving microbiologists, immunologists, clinicians, evolutionists, mathematicians and bio-informaticians. Dr Marlène Roy was also « Attachée temporaire d'enseignement et de recherche » (ATER) in Ecole Pratique des Hautes Etudes.

We dedicate this article in tribute to Pr Christophe Terzian who was at the origin of this research program.

Read the publication: Viral infection impacts transposable element transcript amounts in Drosophila.  Marlène Roy, Barbara Viginier, Édouard Saint-Michel, Frédérick Arnaud,  Maxime Ratinier, and  Marie Fablet. PNAS June 2, 2020 117 (22) 12249-12257; first published May 20, 2020 https://doi.org/10.1073/pnas.2006106117

Modification date : 26 April 2023 | Publication date : 04 June 2020 | Redactor : MR