title: Bat Severe Acute Respiratory Syndrome-Like Coronavirus WIV1 Encodes an Extra Accessory Protein, ORFX, Involved in Modulation of the Host Immune Response.
abstract: Bats harbor severe acute respiratory syndrome (SARS)-like coronaviruses (SL-CoVs) from which the causative agent of the 2002-2003 SARS pandemic is thought to have originated. However, despite the fact that a large number of genetically diverse SL-CoV sequences have been detected in bats, only two strains (named WIV1 and WIV16) have been successfully cultured in vitro These two strains differ from SARS-CoV only in containing an extra open reading frame (ORF) (named ORFX), between ORF6 and ORF7, which has no homology to any known protein sequences. In this study, we constructed a full-length cDNA clone of SL-CoV WIV1 (rWIV1), an ORFX deletion mutant (rWIV1-ΔX), and a green fluorescent protein (GFP)-expressing mutant (rWIV1-GFP-ΔX). Northern blotting and fluorescence microscopy indicate that ORFX was expressed during WIV1 infection. A virus infection assay showed that rWIV1-ΔX replicated as efficiently as rWIV1 in Vero E6, Calu-3, and HeLa-hACE2 cells. Further study showed that ORFX could inhibit interferon production and activate NF-κB. Our results demonstrate for the first time that the unique ORFX in the WIV1 strain is a functional gene involving modulation of the host immune response but is not essential for in vitro viral replication.
  
  
  
  Bats harbor genetically diverse SARS-like coronaviruses (SL-CoVs), and some of them have the potential for interspecies transmission. A unique open reading frame (ORFX) was identified in the genomes of two recently isolated bat SL-CoV strains (WIV1 and -16). It will therefore be critical to clarify whether and how this protein contributes to virulence during viral infection. Here we revealed that the unique ORFX is a functional gene that is involved in the modulation of the host immune response but is not essential for in vitro viral replication. Our results provide important information for further exploration of the ORFX function in the future. Moreover, the reverse genetics system we constructed will be helpful for study of the pathogenesis of this group of viruses and to develop therapeutics for future control of emerging SARS-like infections.
authors.affiliation: Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Lei-Ping
authors.initials: LP
authors.lastname: Zeng
authors.affiliation: Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Yu-Tao
authors.initials: YT
authors.lastname: Gao
authors.affiliation: Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Xing-Yi
authors.initials: XY
authors.lastname: Ge
authors.affiliation: Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Peng
authors.affiliation: Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Xing-Lou
authors.initials: XL
authors.lastname: Yang
authors.affiliation: Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Tan
authors.affiliation: Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: EcoHealth Alliance, New York, New York, USA.
authors.forename: Aleksei A
authors.identifier: http://orcid.org/0000-0001-5544-0431
authors.initials: AA
authors.lastname: Chmura
authors.affiliation: EcoHealth Alliance, New York, New York, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Daszak
authors.affiliation: Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China zlshi@wh.iov.cn.
authors.forename: Zheng-Li
authors.identifier: http://orcid.org/0000-0001-8089-163X
authors.initials: ZL
authors.lastname: Shi
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D002685:Chiroptera / Q000821:virology*; D002522:Chlorocebus aethiops; D006367:HeLa Cells; D006801:Humans; D016899:Interferon-beta / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism; D016366:Open Reading Frames / Q000235:genetics / Q000276:immunology*; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D045169:Severe Acute Respiratory Syndrome / Q000188:drug therapy / Q000276:immunology* / Q000821:virology; D014709:Vero Cells; D014779:Virus Replication / Q000276:immunology*
chemical_list: D000998:Antiviral Agents; D016328:NF-kappa B; D016899:Interferon-beta