title: Severe acute respiratory syndrome coronavirus 7a accessory protein is a viral structural protein.
abstract: Severe acute respiratory syndrome coronavirus (SCoV) 7a protein is one of the viral accessory proteins. In expressing cells, 7a protein exhibits a variety of biological activities, including induction of apoptosis, activation of the mitogen-activated protein kinase signaling pathway, inhibition of host protein translation, and suppression of cell growth progression. Analysis of SCoV particles that were purified by either sucrose gradient equilibrium centrifugation or a virus capture assay, in which intact SCoV particles were specifically immunoprecipitated by anti-S protein monoclonal antibody, demonstrated that 7a protein was associated with purified SCoV particles. Coexpression of 7a protein with SCoV S, M, N, and E proteins resulted in production of virus-like particles (VLPs) carrying 7a protein, while 7a protein was not released from cells expressing 7a protein alone. Although interaction between 7a protein and another SCoV accessory protein, 3a, has been reported, 3a protein was dispensable for assembly of 7a protein into VLPs. S protein was not required for the 7a protein incorporation into VLPs, and yet 7a protein interacted with S protein in coexpressing cells. These data established that, in addition to 3a protein, 7a protein was a SCoV accessory protein identified as a SCoV structural protein.
authors.affiliation: Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, TX 77555-1019, USA.
authors.forename: Cheng
authors.initials: C
authors.lastname: Huang
authors.forename: Naoto
authors.initials: N
authors.lastname: Ito
authors.forename: Chien-Te K
authors.initials: CT
authors.lastname: Tseng
authors.forename: Shinji
authors.initials: S
authors.lastname: Makino
mesh_terms: D015153:Blotting, Western; D002478:Cells, Cultured; D006801:Humans; D047468:Immunoprecipitation; D007668:Kidney / Q000196:embryology / Q000821:virology; D010957:Plasmids; D045473:Severe acute respiratory syndrome-related coronavirus / Q000502:physiology*; D045169:Severe Acute Respiratory Syndrome / Q000821:virology; D014763:Viral Matrix Proteins / Q000502:physiology*; D014764:Viral Proteins / Q000502:physiology*; D015678:Viral Structural Proteins / Q000502:physiology*; D019065:Virus Assembly
chemical_list: D014763:Viral Matrix Proteins; D014764:Viral Proteins; D015678:Viral Structural Proteins; C488151:sars7a protein, SARS virus