Completion of the full-length genome sequence of the infectious salmon anemia virus, an aquatic orthomyxovirus-like, and characterization of mAbs

Mérour, Emilie; LeBerre, Monique; Lamoureux, Annie; Bernard, Julie; Brémont, Michel; Biacchesi, Stéphane

doi:10.1099/vir.0.027417-0

Cited by 22 publications

(19 citation statements)

References 31 publications

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“…Sequences were selected, including the noncoding 5= and 3= UTR ends of the eight genomic segments, from the publications of Fourrier et al, Kulshreshtha et al, and Merour et al (10,33,34). The sequences were from two Scottish isolates (390/98 and 982/08) (33), a Norwegian isolate (Glesvaer/2/90) (10), two Canadian isolates (NBISA01 and RPC NB 98-049) (34), and one Chilean isolate (ADL-PM 3205 ISAV) (34).…”

Section: Methodsmentioning

confidence: 99%

Development of a Reverse Genetic System for Infectious Salmon Anemia Virus: Rescue of Recombinant Fluorescent Virus by Using Salmon Internal Transcribed Spacer Region 1 as a Novel Promoter

Toro-Ascuy

Tambley

Beltrán

et al. 2015

Appl Environ Microbiol

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Infectious salmon anemia (ISA) is a serious disease of marine-farmed Atlantic salmon (Salmo salar) caused by ISA virus (ISAV), belonging to the genus Isavirus, family Orthomyxoviridae. There is an urgent need to understand the virulence factors and pathogenic mechanisms of ISAV and to develop new vaccine approaches. Using a recombinant molecular biology approach, we report the development of a plasmid-based reverse genetic system for ISAV, which includes the use of a novel fish promoter, the Atlantic salmon internal transcribed spacer region 1 (ITS-1). Salmon cells cotransfected with pSS-URG-based vectors expressing the eight viral RNA segments and four cytomegalovirus (CMV)-based vectors that express the four proteins of the ISAV ribonucleoprotein complex allowed the generation of infectious recombinant ISAV (rISAV). We generated three recombinant viruses, wild-type rISAV 901_09 and rISAVr S6-NotI-HPR containing a NotI restriction site and rISAV S6/EGFP-HPR harboring the open reading frame of enhanced green fluorescent protein (EGFP), both within the highly polymorphic region (HPR) of segment 6. All rescued viruses showed replication activity and cytopathic effect in Atlantic salmon kidney-infected cells. The fluorescent recombinant viruses also showed a characteristic cytopathic effect in salmon cells, and the viruses replicated to a titer of 6.5 ؋ 10 5 PFU/ml, similar to that of the wild-type virus. This novel reverse genetics system offers a powerful tool to study the molecular biology of ISAV and to develop a new generation of ISAV vaccines to prevent and mitigate ISAV infection, which has had a profound effect on the salmon industry. Infectious salmon anemia (ISA) is a disease that principally affects Atlantic salmon (Salmo salar), which has caused enormous losses to salmon farming worldwide (1, 2). ISA was first reported in 1984 in Norway (3) and subsequently was identified in Canada (4), Scotland (5), the United States (6), the Faroe Islands (Denmark) (6), and Chile (7). The etiological agent of this disease is the infectious salmon anemia virus (ISAV), a pleomorphic enveloped virus with a diameter of 45 to 140 nm, which belongs to the family Orthomyxoviridae (8). Its genome has 8 negative-polarity singlestranded RNA (ssRNA) segments that encode 10 proteins. Sequence similarity analyses of the genomes of different ISAV isolates show significant variation in the coding regions. In contrast, the untranslated regions (UTR) at both ends of each segment are highly conserved (9-11), as has been described for other orthomyxoviruses as well (e.g., influenza A and B viruses) (12).There is little knowledge at present about the functions of the ISAV proteins. Bioinformatic analyses of the sequences predict that segments 1, 2, and 4 encode the subunits of the RNA-dependent RNA polymerase (RdRp), analogous to PB2, PB1, and PA, respectively, of the influenza A virus. Segment 3 encodes the nucleoprotein (NP), which has been reported to have the capacity to bind ssRNA (13). For influenza virus, it has been shown that t...

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Section: Methodsmentioning

confidence: 99%

Development of a Reverse Genetic System for Infectious Salmon Anemia Virus: Rescue of Recombinant Fluorescent Virus by Using Salmon Internal Transcribed Spacer Region 1 as a Novel Promoter

Toro-Ascuy

Tambley

Beltrán

et al. 2015

Appl Environ Microbiol

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“…An important study from Sandvik et al, in which the nucleotide sequences of the termini of two ISAV vRNA genomic segments were determined and secondary structures for these sequences were predicted using nearest-neighbor thermody-namic rules, established ISAV to be an orthomyxovirus (56). The secondary structure prediction was performed for the 25 terminal nucleotides on genomic segments 6 (originally misidentified as segment 7 [28,41]) and 8 using MulFold, an earlier version of Mfold (59), and predicted a temperaturedependent switch in RNA secondary structures between 15°C, the temperature of the North Atlantic and the optimal temperature for ISAV replication, and 37°C. In this respect, it should be noted that ISAV replication does not occur above 25°C (14).…”

Section: Infectious Salmon Anemia Virus (Isav) Has Emerged As a Greatmentioning

confidence: 99%

Structural Characterization of the Viral and cRNA Panhandle Motifs from the Infectious Salmon Anemia Virus

Brinson

Szakal

Marino

2011

J Virol

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Infectious salmon anemia virus (ISAV) has emerged as a virus of great concern to the aquaculture industry since it can lead to highly contagious and lethal infections in farm-raised salmon populations. While little is known about the transcription/replication cycle of ISAV, initial evidence suggests that it follows molecular mechanisms similar to those found in other orthomyxoviruses, which include the highly pathogenic influenza A (inf A) virus. During the life cycle of orthomyxoviruses, a panhandle structure is formed by the pairing of the conserved 5 and 3 ends of each genomic RNA. This structural motif serves both as a promoter of the viral RNA (vRNA)-dependent RNA polymerase and as a regulatory element in the transcription/replication cycle. As a first step toward characterizing the structure of the ISAV panhandle, here we have determined the secondary structures of the vRNA and the cRNA panhandles on the basis of solution nuclear magnetic resonance (NMR) and thermal melting data. The vRNA panhandle is distinguished by three noncanonical U ⅐ G pairs and one U ⅐ U pair in two stem helices that are linked by a highly stacked internal loop. For the cRNA panhandle, a contiguous stem helix with a protonated C ⅐ A pair near the terminus and tandem downstream U ⅐ U pairs was found. The observed noncanonical base pairs and base stacking features of the ISAV RNA panhandle motif provide the first insight into structural features that may govern recognition by the viral RNA polymerase.

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“…However, sequences similar to the ones obtained by us were recently published for the Glesvaer strain passaged on cell culture (Merour et al . ).…”

Section: Resultsmentioning

confidence: 97%

“…; Merour et al . ). All other ISAV sequences available for this area of PA have a histidine residue in this position.…”

Section: Discussionmentioning

confidence: 97%

Multiple passage of infectious salmon anaemia virus in rainbow trout, Oncorhynchus mykiss (Walbaum), did not induce increased virus load

Olsen

Braaen

Falk

et al. 2012

Journal of Fish Diseases

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The infectious salmon anaemia virus (ISAV) has not been observed to cause natural disease in farmed rainbow trout, Onchorhynchus mykiss (Walbaum), but may cause high mortality in farmed Atlantic salmon, Salmo salar L. In this study, ISAV was passaged 10 times in succession by intraperitoneal injections of serum from previous passage into naïve rainbow trout. The serum viraemia was monitored by real-time qPCR. The rainbow trout in this study became infected but did not develop ISA. No clinical signs were observed in the rainbow trout in any passage, but replication of ISAV was detected from Day 4 post-infection (p.i.). Neither increased relative virus loads nor histopathological and immunohistochemical findings consistent with ISA were observed. However, the expression of interferon type I and Mx genes were slightly up-regulated in the hearts of some individual fish at day 17 p.i. Sequencing of all open reading frames in the ISAV genome of the 10th passage revealed two nucleotide mutations, one in segment 6 coding for the haemagglutinin-esterase (HE) and one in segment 1 coding for the basic polymerase 2 (PB2). The mutation in HE resulted in an amino acid substitution T/K(312) .

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Completion of the full-length genome sequence of the infectious salmon anemia virus, an aquatic orthomyxovirus-like, and characterization of mAbs

Cited by 22 publications

References 31 publications

Development of a Reverse Genetic System for Infectious Salmon Anemia Virus: Rescue of Recombinant Fluorescent Virus by Using Salmon Internal Transcribed Spacer Region 1 as a Novel Promoter

Development of a Reverse Genetic System for Infectious Salmon Anemia Virus: Rescue of Recombinant Fluorescent Virus by Using Salmon Internal Transcribed Spacer Region 1 as a Novel Promoter

Structural Characterization of the Viral and cRNA Panhandle Motifs from the Infectious Salmon Anemia Virus

Multiple passage of infectious salmon anaemia virus in rainbow trout, Oncorhynchus mykiss (Walbaum), did not induce increased virus load

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