Long dsRNAs promote an anti-viral response in Pacific oyster hampering ostreid herpesvirus 1 replication

• Published in: Journal of Experimental Biology
• Main Authors: Pauletto, Marianna, Segarra, Ameíie, Montagnani, Caroline, Quillien, Virgile, Faury, Nicole, Le Grand, Jacqueline, Miner, Philippe, Petton, Bruno, Labreuche, Yannick, Fleury, Elodie, Fabioux, Caroline, Bargelloni, Luca, Renault, Tristan, Huvet, Arnaud
• Other Authors: Università degli Studi di Padova = University of Padua (Unipd), Unité Santé, Génétique et Microbiologie des Mollusques (SGMM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Interactions Hôtes-Pathogènes-Environnements (IHPE), Université de Perpignan Via Domitia (UPVD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biologie Intégrative des Modèles Marins (LBI2M), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff = Roscoff Marine Station (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Station biologique de Roscoff = Roscoff Marine Station (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Unité Amélioration génétique, Santé animale et Environnement (AGSAE), ANR-08-GENM-0041,Gametogenes,Génomiques de la gamétogénèse chez l'huître creuse Crassostrea gigas(2008), European Project: 245119,EC:FP7:KBBE,FP7-KBBE-2009-3,REPROSEED(2010)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: Inhibitor of NF-κB; RNA interference; Marine bivalve; Ostreid herpesvirus 1; ACL; Anti-viral response; [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE]; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Crassostrea gigas; Pacific oyster
• Online Access: https://hal.science/hal-01632365; https://hal.science/hal-01632365/document; https://hal.science/hal-01632365/file/Pauletto-2017-JExpBiol-Long.pdf; https://doi.org/10.1242/jeb.156299

International audience Double-stranded RNA (dsRNA)-mediated genetic interference (RNAi) is a widely used reverse genetic tool for determining the loss-of-function phenotype of a gene. Here, the possible induction of an immune response by long dsRNA was tested in a marine bivalve (Crassostrea gigas), as well as the specific role of the subunit 2 of the nuclear factor κB inhibitor (IκB2). This gene is a candidate of particular interest for functional investigations in the context of oyster mass mortality events, as Cg-IκB2 mRNA levels exhibited significant variation depending on the amount of ostreid herpesvirus 1 (OsHV-1) DNA detected. In the present study, dsRNAs targeting Cg-IκB2 and green fluorescent protein genes were injected in vivo into oysters before being challenged by OsHV-1. Survival appeared close to 100% in both dsRNA-injected conditions associated with a low detection of viral DNA and a low expression of a panel of 39 OsHV-1 genes as compared with infected control. Long dsRNA molecules, both Cg-IκB2-and GFP-dsRNA, may have induced an anti-viral state controlling the OsHV-1 replication and precluding the understanding of the specific role of Cg-IκB2. Immune-related genes including Cg-IκB1, Cg-Rel1, Cg-IFI44, Cg-PKR and Cg-IAP appeared activated in the dsRNA-injected condition, potentially hampering viral replication and thus conferring a better resistance to OsHV-1 infection. We revealed that long dsRNA-mediated genetic interference triggered an anti-viral state in the oyster, emphasizing the need for new reverse genetics tools for assessing immune gene function and avoiding off-target effects in bivalves.