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), Laboratoire de Génétique et Pathologie des Mollusques Marins (LGPMM), Unité Santé, Génétique et Microbiologie des Mollusques (SGMM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-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), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), 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), Laboratoire de Génétique et Pathologie (LGP), 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.