title: Identification of an interferon antagonist protein encoded by segment 7 of infectious salmon anaemia virus.
abstract: Infectious salmon anaemia virus (ISAV) is an orthomyxovirus and member of the genus Isavirus, which contains eight genomic segments coding for ten viral proteins. This study focussed on identifying the function of the largest protein encoded by ISAV genomic segment 7 (7i), which like influenza A segment 7 encodes two proteins, one of which is based on removal of an intron from the primary transcript. Using two independent methods, an Mx1 promoter-driven reporter system and real-time PCR of FACS-sorted transfected cells, we demonstrate that the non-structural ISAV 7i protein is an interferon-signalling antagonist. Other transfection studies indicated a predominantly cytoplasmic localisation of the expressed protein, which is consistent with this role. The demonstration that ISAV segment 7 encodes a putative non-structural IFN system antagonist reveals a difference with influenza A virus, where segment 7, which shares a similar coding strategy, encodes the structural matrix proteins.
authors.affiliation: FRS Marine Laboratory, Aberdeen AB11 9DB, UK.
authors.forename: Alastair J A
authors.initials: AJ
authors.lastname: McBeath
authors.forename: Bertrand
authors.initials: B
authors.lastname: Collet
authors.forename: Richard
authors.initials: R
authors.lastname: Paley
authors.forename: Sophie
authors.initials: S
authors.lastname: Duraffour
authors.forename: Vidar
authors.initials: V
authors.lastname: Aspehaug
authors.forename: Eirik
authors.initials: E
authors.lastname: Biering
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Secombes
authors.forename: Michael
authors.initials: M
authors.lastname: Snow
mesh_terms: D000818:Animals; D019677:Artificial Gene Fusion; D002460:Cell Line; D003593:Cytoplasm / Q000737:chemistry; D005434:Flow Cytometry; D017930:Genes, Reporter; D016679:Genome, Viral; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D009980:Influenza A virus / Q000235:genetics; D007372:Interferons / Q000037:antagonists & inhibitors*; D046829:Isavirus / Q000235:genetics* / Q000502:physiology; D049409:Luciferases, Firefly / Q000032:analysis / Q000235:genetics; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D012367:RNA, Viral / Q000032:analysis; D012474:Salmon; D017361:Viral Nonstructural Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*
chemical_list: D012333:RNA, Messenger; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; C485197:luciferase, Photinus; D049452:Green Fluorescent Proteins; D007372:Interferons; D049409:Luciferases, Firefly