The intracellular sites of early replication and budding of SARS-coronavirus.
In this study, we analyzed the replication and budding sites of severe acute respiratory syndrome coronavirus (SARS-CoV) at early time points of infection. We detected cytoplasmic accumulations containing the viral nucleocapsid protein, viral RNA and the non-structural protein nsp3. Using EM techniques, we found that these putative viral replication sites were associated with characteristic membrane tubules and double membrane vesicles that most probably originated from ER cisternae. In addition to its presence at the replication sites, N also accumulated in the Golgi region and colocalized with the viral spike protein. Immuno-EM revealed that budding occurred at membranes of the ERGIC (ER-Golgi intermediate compartment) and the Golgi region as early as 3 h post infection, demonstrating that SARS-CoV replicates surprisingly fast. Our data suggest that SARS-CoV establishes replication complexes at ER-derived membranes. Later on, viral nucleocapsids have to be transported to the budding sites in the Golgi region where the viral glycoproteins accumulate and particle formation occurs.
Stertz
Silke
S
Department of Virology, University of Freiburg, D-79008 Freiburg, Germany.
Reichelt
Mike
M
Spiegel
Martin
M
Kuri
Thomas
T
Martínez-Sobrido
Luis
L
García-Sastre
Adolfo
A
Weber
Friedemann
F
Kochs
Georg
G
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure / Q000821:virology; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000378:metabolism / Q000648:ultrastructure / Q000821:virology; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D008854:Microscopy, Electron; D016253:Microscopy, Immunoelectron; D019590:Nucleocapsid Proteins / Q000378:metabolism; D021381:Protein Transport; D012367:RNA, Viral / Q000378:metabolism; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism; D045473:Severe acute respiratory syndrome-related coronavirus / Q000502:physiology*; D045169:Severe Acute Respiratory Syndrome / Q000821:virology*; D064370:Spike Glycoprotein, Coronavirus; D013997:Time Factors; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000378:metabolism; D017361:Viral Nonstructural Proteins / Q000378:metabolism; D014779:Virus Replication
D008562:Membrane Glycoproteins; D019590:Nucleocapsid Proteins; D012367:RNA, Viral; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; D017361:Viral Nonstructural Proteins; C578557:spike glycoprotein, SARS-CoV; C510959:Nsp3 protein, SARS-CoV; D012324:RNA-Dependent RNA Polymerase