title: A nuclear localization of the infectious haematopoietic necrosis virus NV protein is necessary for optimal viral growth.
abstract: The nonvirion (NV) protein of infectious hematopoietic necrosis virus (IHNV) has been previously reported to be essential for efficient growth and pathogenicity of IHNV. However, little is known about the mechanism by which the NV supports the viral growth. In this study, cellular localization of NV and its role in IHNV growth in host cells was investigated. Through transient transfection in RTG-2 cells of NV fused to green fluorescent protein (GFP), a nuclear localization of NV was demonstrated. Deletion analyses showed that the (32)EGDL(35) residues were essential for nuclear localization of NV protein, and fusion of these 4 amino acids to GFP directed its transport to the nucleus. We generated a recombinant IHNV, rIHNV-NV-ΔEGDL in which the (32)EGDL(35) was deleted from the NV. rIHNVs with wild-type NV (rIHNV-NV) or with the NV gene replaced with GFP (rIHNV-ΔNV-GFP) were used as controls. RTG-2 cells infected with rIHNV-ΔNV-GFP and rIHNV-NV-ΔEGDL yielded 12- and 5-fold less infectious virion, respectively, than wild type rIHNV-infected cells at 48 h post-infection (p.i.). While treatment with poly I∶C at 24 h p.i. did not inhibit replication of wild-type rIHNVs, replication rates of rIHNV-ΔNV-GFP and rIHNV-NV-ΔEGDL were inhibited by poly I∶C. In addition, both rIHNV-ΔNV and rIHNV-NV-ΔEGDL induced higher levels of expressions of both IFN1 and Mx1 than wild-type rIHNV. These data suggest that the IHNV NV may support the growth of IHNV through inhibition of the INF system and the amino acid residues of (32)EGDL(35) responsible for nuclear localization are important for the inhibitory activity of NV.
authors.affiliation: Department of Biological Sciences, University of Ulsan, Ulsan, Korea.
authors.forename: Myeong Kyu
authors.initials: MK
authors.lastname: Choi
authors.forename: Chang Hoon
authors.initials: CH
authors.lastname: Moon
authors.forename: Myoung Seok
authors.initials: MS
authors.lastname: Ko
authors.forename: Unn-Hwa
authors.initials: UH
authors.lastname: Lee
authors.forename: Wha Ja
authors.initials: WJ
authors.lastname: Cho
authors.forename: Seung Ju
authors.initials: SJ
authors.lastname: Cha
authors.forename: Jeong Wan
authors.initials: JW
authors.lastname: Do
authors.forename: Gang Joon
authors.initials: GJ
authors.lastname: Heo
authors.forename: Soo Geun
authors.initials: SG
authors.lastname: Jeong
authors.forename: Yoo Sik
authors.initials: YS
authors.lastname: Hahm
authors.forename: Abdallah
authors.initials: A
authors.lastname: Harmache
authors.forename: Michel
authors.initials: M
authors.lastname: Bremont
authors.forename: Gael
authors.initials: G
authors.lastname: Kurath
authors.forename: Jeong Woo
authors.initials: JW
authors.lastname: Park
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D003530:Cyprinidae; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D029142:Infectious hematopoietic necrosis virus / Q000254:growth & development* / Q000472:pathogenicity*; D019913:Nuclear Localization Signals; D017686:Oncorhynchus mykiss; D011070:Poly I-C / Q000235:genetics; D011401:Promoter Regions, Genetic; D012367:RNA, Viral; D018353:Rhabdoviridae Infections / Q000378:metabolism / Q000821:virology*; D012474:Salmon; D013347:Subcellular Fractions; D014759:Viral Envelope Proteins / Q000378:metabolism*; D014779:Virus Replication
chemical_list: C104040:IHNVG protein, Infectious hematopoietic necrosis virus; D019913:Nuclear Localization Signals; D012367:RNA, Viral; D014759:Viral Envelope Proteins; D049452:Green Fluorescent Proteins; D011070:Poly I-C