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Severe acute respiratory syndrome coronavirus envelope protein regulates cell stress response and apoptosis
Journal article   Open access   Peer reviewed

Severe acute respiratory syndrome coronavirus envelope protein regulates cell stress response and apoptosis

Marta L DeDiego, Jose L Nieto-Torres, Jose M Jiménez-Guardeño, Jose A Regla-Nava, Enrique Alvarez, Juan Carlos Oliveros, Jincun Zhao, Craig Fett, Stanley Perlman and Luis Enjuanes
PLoS pathogens, Vol.7(10), e1002315
10/2011
DOI: 10.1371/journal.ppat.1002315
PMCID: PMC3197621
PMID: 22028656
url
https://doi.org/10.1371/journal.ppat.1002315View
Published (Version of record) Open Access

Abstract

Severe acute respiratory syndrome virus (SARS-CoV) that lacks the envelope (E) gene (rSARS-CoV-ΔE) is attenuated in vivo. To identify factors that contribute to rSARS-CoV-ΔE attenuation, gene expression in cells infected by SARS-CoV with or without E gene was compared. Twenty-five stress response genes were preferentially upregulated during infection in the absence of the E gene. In addition, genes involved in signal transduction, transcription, cell metabolism, immunoregulation, inflammation, apoptosis and cell cycle and differentiation were differentially regulated in cells infected with rSARS-CoV with or without the E gene. Administration of E protein in trans reduced the stress response in cells infected with rSARS-CoV-ΔE or with respiratory syncytial virus, or treated with drugs, such as tunicamycin and thapsigargin that elicit cell stress by different mechanisms. In addition, SARS-CoV E protein down-regulated the signaling pathway inositol-requiring enzyme 1 (IRE-1) of the unfolded protein response, but not the PKR-like ER kinase (PERK) or activating transcription factor 6 (ATF-6) pathways, and reduced cell apoptosis. Overall, the activation of the IRE-1 pathway was not able to restore cell homeostasis, and apoptosis was induced probably as a measure to protect the host by limiting virus production and dissemination. The expression of proinflammatory cytokines was reduced in rSARS-CoV-ΔE-infected cells compared to rSARS-CoV-infected cells, suggesting that the increase in stress responses and the reduction of inflammation in the absence of the E gene contributed to the attenuation of rSARS-CoV-ΔE.
Viral Envelope Proteins - genetics Severe Acute Respiratory Syndrome - virology Stress, Physiological - genetics Humans SARS Virus - pathogenicity Host-Pathogen Interactions SARS Virus - genetics Virulence - genetics Virus Replication Gene Expression Regulation, Viral Gene Deletion Viral Envelope Proteins - metabolism Cell Line, Tumor Severe Acute Respiratory Syndrome - metabolism Stress, Physiological - drug effects Apoptosis - physiology Severe Acute Respiratory Syndrome - pathology

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