Transcriptome characterization and gene expression of Epinephelus spp in endoplasmic reticulum stress-related pathway during betanodavirus infection in vitro

Abstract

BackgroundGrouper (Epinephelus spp) is an economically important fish species worldwide. However, viral pathogens such as nervous necrosis virus (NNV) have been causing severe infections in the fish, resulting in great loss in the grouper aquaculture industry. Yet, the understanding of the molecular mechanisms underlying the pathogenicity of NNV is still inadequate, mainly due to insufficient genomic information of the host.ResultsDe novo assembly of grouper transcriptome in the grouper kidney (GK) cells was conducted by using short read sequencing technology of Solexa/Illumina. A sum of 66,582 unigenes with mean length of 603 bp were obtained, and were annotated according to Gene Ontology (GO) and Clusters of Orthologous Groups (COG). In addition, the tag-based digital gene expression (DGE) system was used to investigate the gene expression and pathways associated with NNV infection in GK cells. The analysis revealed endoplasmic reticulum (ER) stress response was prominently affected in NNV-infected GK cells. A further analysis revealed an interaction between the NNV capsid protein and the ER chaperone immunoglobulin heavy-chain binding protein (BiP). Furthermore, exogenous expression of NNV capsid protein was able to induce XBP-1 mRNA splicing in vivo, suggesting a role of the capsid protein in the NNV-induced ER stress.ConclusionsOur data presents valuable genetic information for Epinephelus spp., which will benefit future study in this non-model but economically important species. The DGE profile of ER stress response in NNV-infected cells provides information of many important components associated with the protein processing in ER. Specifically, we showed that the viral capsid protein might play an important role in the ER stress response.

Betanodavirus and VER Disease: A 30-year Research Review

“…In another study also performed with DLB-1 cells, the transcriptomic profiles obtained from European sea bass head-kidney leucocytes incubated with NNV infected and uninfected cells were very similar, supporting that cell-mediated cytotoxic activity in sea bass is not primed upon NNV infection [231]. Other cells used for transcriptome analysis were Asian seabass (Lateolabrax japonicus) epithelial cells (SB) [229], grouper kidney (GK) cells [228] and Lateolabrax japonicus brain cells (LJB) [233]. The assembly of the transcriptome of NNV-infected SB cells, as in the previously described cell lines, showed a strong induction of various genes relevant to innate immunity which were identified as receptor-transporting 3 (RTP3), Viperin, IRF3, IFN and two heat shock protein (HSP) family members (Hsp30 and 70) [229].…”

“…In recent years, a great deal of progress has been made on high-throughput tools for sequencing the transcriptome (RNA-Seq), enabling genome-wide transcriptomic analysis and providing valuable information for understanding virus-host interactions [227]. Different transcriptomic analyses have been performed on both NNV-infected cells [228][229][230][231][232][233] and fish [234][235][236][237][238].…”

Expression analysis of heat shock protein genes during Aeromonas hydrophila infection in rohu, Labeo rohita, with special reference to molecular characterization of Grp78

“…Interaction of host Grp78 or Bip protein with viral capsid was also evident in grouper, Epinephelus spp. (Lu et al 2012). However, a functional characterization of Grp78 protein during bacterial infection in fish is needed to further identify its mechanism of action.…”

Contrasted Innate Responses to Two Viruses in Zebrafish: Insights into the Ancestral Repertoire of Vertebrate IFN-Stimulated Genes

“…Large-scale analyses of transcriptome response to viral infection have been carried out in a number of other fish species, including Atlantic salmon head kidney cell response to SAV-1 (12), Atlantic salmon heart response to piscine myocarditis virus (13), orange-spotted grouper spleen response to Singapore grouper iridovirus (14), response of the grouper kidney cell line infected by betanodavirus (15), and Atlantic cod brain response to nervous necrosis virus (16). These studies generally addressed the transcriptional response of a particular tissue after infection with a given virus, and resulted in overlapping but largely distinct sets of modulated genes.…”