Identification of sea perch (Lateolabrax japonicus) ribonucleoprotein PTB-Binding 1 involved in antiviral immune response against RGNNV

RIG-I-like receptors (RLRs) can recognize viral RNA and initiate innate antiviral response. In earlier studies, we demonstrated that RLRs were implicated in the antiviral immunity against RGNNV in the seawater fish sea perch (Lateolabrax japonicus). However, potential regulators of RLRs-mediated signaling pathways involved in RGNNV infection remain unclear. In this study, a novel ribonucleoprotein 1,113 binding 1 (Raven) of sea perch (LjRAVER1) was identified for the first time. The cDNA of LjRAVERI was 4066 bp in length and encoded a deduced polypeptide of 733 amino acids. Phylogenetic analysis revealed a closer affinity of LjRAVER1 with Larirnichthys Crocea Raverl. LjRAVERI mRNA was constitutively expressed in all 10 sampled tissues, and rapidly and significantly increased in vivo upon RGNNV infection. Time course analysis showed that LjRAVERI transcripts were significantly increased both in vivo and in vitro after RGNNV infection. Viral infection and poly I:C treatment caused translocation of LjRAVERI from the nucleus to the cytoplasm. Ectopic expression of LjRAVERI increased the transcription level of several RLR signaling pathway related genes inducible by poly I:C treatment in vitro. Moreover, the viral gene transcription and virus production of RGNNV were significantly decreased in LjRAVERI overexpressing cells. Luciferase reporter assays demonstrated that overexpression of LjRAVER1 significantly increased the promoter activity of zebrafish IFN1. Taken together, these findings indicated that LjRAVERI might be an important component of RLR signaling pathway and involved in RLR pathway mediated IFN response in sea perch. (C) 2016 Elsevier Ltd. All rights reserved.