Long dsRNAs promote an anti-viral response in Pacific oyster hampering ostreid herpesvirus 1 replication
|Author(s)||Pauletto Marianna1, Segarra Amelie2, Montagnani Caroline3, Quillien Virgile4, Faury Nicole2, Le Grand Jacqueline4, Miner Philippe4, Petton Bruno4, Labreuche Yannick5, Fleury Elodie4, Fabioux Caroline6, Bargelloni Luca1, Renault Tristan7, Huvet Arnaud4|
|Affiliation(s)||1 : Univ Padua, Dept Comparat Biomed & Food Sci, Viale Univ 16, I-35020 Legnaro, PD, Italy.
2 : IFREMER, Lab Genet & Pathol Mollusques Marins, F-17390 La Tremblade, France.
3 : Univ Montpellier, IFREMER, Univ Perpignan Via Domitia, IHPE UMR 5244,CNRS, F-34095 Montpellier, France.
4 : UBO, UMR CNRS 6539, IFREMER, IRD,LEMAR, F-29280 Plouzane, France.
5 : UPMC Paris 06, Sorbonne Univ, CNRS, UMR 8227,Stn Biol Roscoff, CS 90074, F-29688 Roscoff, France.
6 : Univ Bretagne Occidentale, UMR CNRS 6539, IFREMER, Inst Univ Europeen Mer,IRD,LEMAR, F-29280 Plouzane, France.
7 : IFREMER, Dept Ressources Biol & Environm, Rue lIle dYeu, F-44000 Nantes, France.
|Source||Journal Of Experimental Biology (0022-0949) (Company Of Biologists Ltd), 2017-10-18 , Vol. 220 , N. 20 , P. 3671-3685|
|WOS© Times Cited||13|
|Keyword(s)||Anti-viral response, RNA interference, Inhibitor of NF-kappa B, Marine bivalve, Ostreid herpesvirus 1|
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 kappa B inhibitor (I kappa B2). This gene is a candidate of particular interest for functional investigations in the context of oyster mass mortality events, as Cg-I kappa B2 mRNA levels exhibited significant variation depending on the amount of ostreid herpesvirus 1 (OsHV-1) DNA detected. In the present study, dsRNAs targeting Cg-I kappa B2 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-I kappa B2- 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-I kappa B2. Immune-related genes including Cg-I kappa B1, 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.