Auxiliary proteins of infectious salmon anemia virus

Abstract

Infectious salmon anemia virus (ISAV) causes an infection with high mortality in farmed Atlantic salmon, characterized by anemia and circulatory collapse. ISAV is an RNA virus, but replicate in the nucleus of the cell. Therefore it depends on tightly control of the import and export of viral proteins across the nuclear membrane. This study focuses on the auxiliary proteins encoded by ISAV, which functions are essential for the success of the virus replication, but relatively poorly studied. From ISAV genomic segment 7 two protein are encoded. The multifunctional non-structural protein which antagonize the innate immune response of the cell, and one protein with unknown function. The study concludes that the latter is a nuclear export protein, NEP, that helps to coordinate the transport of virus proteins through the pores of the nuclear membrane. Also from ISAV genomic segment 8, there are two protein encoded; the matrix and a structural protein (s8ORF2) that binds RNA and antagonize type I interferon. The study concludes that the latter protein acts as a modifier of the RNA interference system of the cell. The thesis contributes to new basic knowledge since the auxiliary proteins of ISAV so far have been poorly described. Although the thesis only focuses on two proteins, the characterization of these proteins helps to understand pathogenesis of the virus.

Infeksiøs laksanemi (ILA) er en viktig sykdom hos oppdrettslaks (Salmo salar) som har forårsaket store økonomisk tap i flere land. Sykdommen er forårsaket av ILA-virus (ILAV) i virusfamilien Orthomyxoviridae hvor det utgjør slekten Isavirus. ILAV har et genom bestående av åtte RNA-segmenter som er enkelttrådete (ss) og har negativ-sense. Viruset har mange fellestrekk med influensavirus når det gjelder morfologiske-, biokjemiske-, fysisk-kjemiske- og replikasjons-egenskaper. Kunnskap om funksjonen til de enkelte virusproteiner er lite kjent. I dette arbeidet ble funksjoner til virusproteiner som ikke er viktige byggesteiner i viruspartikkelen studert.