title: Equine viperin restricts equine infectious anemia virus replication by inhibiting the production and/or release of viral Gag, Env, and receptor via distortion of the endoplasmic reticulum.
abstract: Viperin is an endoplasmic reticulum (ER)-associated multifunctional protein that regulates virus replication and possesses broad antiviral activity. In many cases, viperin interferes with the trafficking and budding of viral structural proteins by distorting the membrane transportation system. The lentivirus equine infectious anemia virus (EIAV) has been studied extensively. In this study, we examined the restrictive effect of equine viperin (eViperin) on EIAV replication and investigated the possible molecular basis of this restriction to obtain insights into the effect of this cellular factor on retroviruses. We demonstrated that EIAV infection of primary equine monocyte-derived macrophages (eMDMs) upregulated the expression of eViperin. The overexpression of eViperin significantly inhibited the replication of EIAV in eMDMs, and knockdown of eViperin transcription enhanced the replication of EIAV in eMDMs by approximately 45.8%. Further experiments indicated that eViperin restricts EIAV at multiple steps of viral replication. The overexpression of eViperin inhibited EIAV Gag release. Both the α-helix domain and radical S-adenosylmethionine (SAM) domain were required for this activity. However, the essential motifs in SAM were different from those reported for the inhibition of HIV-1 Gag by human viperin. Furthermore, eViperin disrupted the synthesis of both EIAV Env and receptor, which consequently inhibited viral production and entry, respectively, and this disruption was dependent on the eViperin α-helix domain. Using immunofluorescence assays and electron microscopy, we demonstrated that the α-helix domain is responsible for the distortion of the endoplasmic reticulum (ER). Finally, EIAV did not exhibit counteracting eViperin at the protein level.
  
  
  OBJECTIVE
  In previous studies, viperin was indicated as restricting virus replications primarily by the inhibition of virus budding. Here, we show that viperin may have multiple antiviral mechanisms, including the reduction of EIAV Gag budding and Env expression, and these activities are dependent on different viperin domains. We especially demonstrate that the overexpression of viperin inhibits EIAV entry by decreasing the level of virus receptor. Therefore, viperin restriction of viruses is determined largely by the dependence of virus on the cellular membrane transportation system.
authors.affiliation: Biotechnology Institute of Southern Medical University, Guangzhou, China State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Yan-Dong
authors.initials: YD
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Na
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Chun-Hui
authors.initials: CH
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Yang
authors.affiliation: The First Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Xian-Qiu
authors.initials: XQ
authors.lastname: Fu
authors.affiliation: The First Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Yu-Hong
authors.initials: YH
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Li-Hua
authors.initials: LH
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Jia-Yi
authors.initials: JY
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Yue-Zhi
authors.initials: YZ
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Xue-Feng
authors.initials: XF
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China Harbin Pharmaceutical Group Biovaccine Company, Harbin, China jianhua_uc@126.com chengyaoli@hotmail.com.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Zhou
authors.affiliation: Biotechnology Institute of Southern Medical University, Guangzhou, China jianhua_uc@126.com chengyaoli@hotmail.com.
authors.forename: Cheng-Yao
authors.initials: CY
authors.lastname: Li
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure / Q000821:virology*; D005455:Fluorescent Antibody Technique; D015497:HIV-1; D006736:Horses; D054884:Host-Pathogen Interactions; D004860:Infectious Anemia Virus, Equine / Q000276:immunology* / Q000502:physiology*; D008264:Macrophages / Q000276:immunology / Q000821:virology; D008854:Microscopy, Electron; D014764:Viral Proteins / Q000378:metabolism*; D057074:Virus Release; D014779:Virus Replication
chemical_list: D014764:Viral Proteins