title: Nucleocapsid-independent specific viral RNA packaging via viral envelope protein and viral RNA signal.
abstract: For any of the enveloped RNA viruses studied to date, recognition of a specific RNA packaging signal by the virus's nucleocapsid (N) protein is the first step described in the process of viral RNA packaging. In the murine coronavirus a selective interaction between the viral transmembrane envelope protein M and the viral ribonucleoprotein complex, composed of N protein and viral RNA containing a short cis-acting RNA element, the packaging signal, determines the selective RNA packaging into virus particles. In this report we show that expressed coronavirus envelope protein M specifically interacted with coexpressed noncoronavirus RNA transcripts containing the short viral packaging signal in the absence of coronavirus N protein. Furthermore, this M protein-packaging signal interaction led to specific packaging of the packaging signal-containing RNA transcripts into coronavirus-like particles in the absence of N protein. These findings not only highlight a novel RNA packaging mechanism for an enveloped virus, where the specific RNA packaging can occur without the core or N protein, but also point to a new, biologically important general model of precise and selective interaction between transmembrane proteins and specific RNA elements.
authors.affiliation: Department of Microbiology and Immunology, The University of Texas Medical Branch at Galveston, Galveston, Texas 77555-1019, USA.
authors.forename: Krishna
authors.initials: K
authors.lastname: Narayanan
authors.forename: Chun-Jen
authors.initials: CJ
authors.lastname: Chen
authors.forename: Junko
authors.initials: J
authors.lastname: Maeda
authors.forename: Shinji
authors.initials: S
authors.lastname: Makino
mesh_terms: D000818:Animals; D000086862:Coronavirus M Proteins; D051379:Mice; D006517:Murine hepatitis virus / Q000235:genetics / Q000378:metabolism*; D019251:Nucleocapsid / Q000378:metabolism*; D019590:Nucleocapsid Proteins; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014763:Viral Matrix Proteins / Q000378:metabolism*; D014771:Virion / Q000378:metabolism; D019065:Virus Assembly
chemical_list: D000086862:Coronavirus M Proteins; D019590:Nucleocapsid Proteins; D012367:RNA, Viral; D014763:Viral Matrix Proteins; C099600:nucleocapsid protein, Hepatitis virus