[Cell entry mechanisms of coronaviruses].
Enveloped viruses enter into cells via fusion of their envelope and cellular membrane. Spike (S) protein of coronavirus (CoV) is responsible for entry events. We studied the cell entry mechanisms of two different CoVs, murine coronavirus mouse hepatitis virus (MHV) and severe acute respiratory syndrome coronavirus (SARS-CoV). MHV-JHM that induces syncytia in infected cells entered directly from cell surface, i.e., fusion of envelope and plasma membrane, whereas SARS-CoV and MHV-2 that fail to induce syncytia entered via endosome in a protease-dependent fashion, i.e., fusion of envelope and endosomal membrane. The latter viruses entered directly from cell surface, when receptor-bound viruses were treated with proteases that activate fusion activity of their S proteins. The entry pathway of SARS-CoV could influence the severity of the disease. It was also reveled that a highly neurovirulent JHM spread in a receptor-independent fashion, which could result in a high neuropathogenicity of the virus.
Taguchi
Fumihiro
F
Laboratory of Virology and Viral Diseases, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University. ftaguchi@nvlu.ac.jp
Matsuyama
Shutoku
S
D000818:Animals; D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D002462:Cell Membrane / Q000821:virology; D017934:Coronavirus / Q000472:pathogenicity*; D011992:Endosomes; D006801:Humans; D008561:Membrane Fusion; D008562:Membrane Glycoproteins / Q000502:physiology*; D051379:Mice; D010447:Peptide Hydrolases / Q000502:physiology; D011991:Receptors, Virus / Q000502:physiology; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins / Q000502:physiology*
D015703:Antigens, CD; C069847:CD66 antigens; D015815:Cell Adhesion Molecules; D008562:Membrane Glycoproteins; D011991:Receptors, Virus; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus; D010447:Peptide Hydrolases