SARS-Coronavirus Replication Is Supported by a Reticulovesicular Network of Modified Endoplasmic Reticulum

By K. Knoops, M. Kikkert, S. V. D. Worm, Jessika C. Zevenhoven-Dobbe, Y. van der Meer, A. Koster, A. Mommaas, E. Snijder. PLoS Biology, 2008

993 citations recorded by the source corpus.

Positive-strand RNA viruses, a large group including human pathogens such as SARS-coronavirus (SARS-CoV), replicate in the cytoplasm of infected host cells. Their replication complexes are commonly associated with modified host cell membranes. Membrane structures supporting viral RNA synthesis range from distinct spherular membrane invaginations to more elaborate webs of packed membranes and vesicles. Generally, their ultrastructure, morphogenesis, and exact role in viral replication remain to be defined. Poorly characterized double-membrane vesicles (DMVs) were previously implicated in SARS-CoV RNA synthesis. We have now applied electron tomography of cryofixed infected cells for the three-dimensional imaging of coronavirus-induced membrane alterations at high resolution. Our analysis defines a unique reticulovesicular network of modified endoplasmic reticulum that integrates convoluted membranes, numerous interconnected DMVs (diameter 200–300 nm), and “vesicle packets” apparently arising from DMV merger. The convoluted membranes were most abundantly immunolabeled for viral replicase subunits. However, double-stranded RNA, presumably revealing the site of viral RNA synthesis, mainly localized to the DMV interior. Since we could not discern a connection between DMV interior and cytosol, our analysis raises several questions about the mechanism of DMV formation and the actual site of SARS-CoV RNA synthesis. Our data document the extensive virus-induced reorganization of host cell membranes into a network that is used to organize viral replication and possibly hide replicating RNA from antiviral defense mechanisms. Together with biochemical studies of the viral enzyme complex, our ultrastructural description of this “replication network” will aid to further dissect the early stages of the coronavirus life cycle and its virus-host interactions.

Subfields: Animal Science and Zoology, Immunology, Infectious Diseases

View Paper: https://www.semanticscholar.org/paper/82ef5d93dc7dd6b35e8411969e33633b402e5acc

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Citations in the corpus

A structural analysis of M protein in coronavirus assembly and morphology (2010, background): “Coronavirus assembly is then completed at the membrane of a pre-Golgi compartment, as shown most recently in a tomography study of intracellular structures involved in virus replication and assembly (Knoops et al., 2008).”
SARS-CoV-2 productively infects human gut enterocytes (2020, background): “S3A -B) as shown previously (26, 27) .”
Immunology of COVID-19: Current State of the Science (2020, positive): “To evade PRRs, dsRNA is first shielded by membrane-bound compartments that form during viral replication of SARSCoV-1 (Knoops et al., 2008).”
Nsp3 of coronaviruses: Structures and functions of a large multi-domain protein (2017, methodology): “Nsp3 and Nsp5 were detected on the CMs in SARS-CoV-infected cells by immunogold electron microscopy (Knoops et al., 2008).”
Composition and Three-Dimensional Architecture of the Dengue Virus Replication and Assembly Sites (2009, methodology): “It has been successfully employed to determine the architecture of virus-induced membrane alterations (Knoops et al., 2008; Kopek et al., 2007) or the organization of other large intracellular structures (Hoog et al.”
An evolving arsenal: viral RNA detection by RIG-I-like receptors (2014, background): “SARS-CoV induces formation of doublemembrane vesicles on an altered endoplasmic reticulum, as revealed by electron tomography images of infected cells [45].”
Molecular immune pathogenesis and diagnosis of COVID-19 (2020, positive): “Those nsps rearrange membranes originating from the rough endoplasmic reticulum (RER) into double-membrane vesicles where viral replication and transcription occur [8,9].”