Journal article

Authors list: Krähling, V; Stein, DA; Spiegel, M; Weber, F; Mühlberger, E

Publication year: 2009

Pages: 2298-2309

Journal: Journal of Virology

Volume number: 83

Issue number: 5

ISSN: 0022-538X

eISSN: 1098-5514

DOI Link: https://doi.org/10.1128/JVI.01245-08

Publisher: American Society for Microbiology

Abstract: 
In this study, infection of 293/ACE2 cells with severe acute respiratory syndrome coronavirus (SARS-CoV) activated several apoptosis-associated events, namely, cleavage of caspase-3, caspase-8, and poly(ADP-ribose) polymerase 1 (PARP), and chromatin condensation and the phosphorylation and hence inactivation of the eukaryotic translation initiation factor 2 alpha (eIF2 alpha). In addition, two of the three cellular eIF2 alpha kinases known to be virus induced, protein kinase R (PKR) and PKR-like endoplasmic reticulum kinase (PERK), were activated by SARS-CoV. The third kinase, general control nonderepressible-2 kinase (GCN2), was not activated, but late in infection the level of GCN2 protein was significantly reduced. Reverse transcription-PCR analyses revealed that the reduction of GCN2 protein was not due to decreased transcription or stability of GCN2 mRNA. The specific reduction of PKR protein expression by antisense peptide-conjugated phosphorodiamidate morpholino oligomers strongly reduced cleavage of PARP in infected cells. Surprisingly, the knockdown of PKR neither enhanced SARS-CoV replication nor abrogated SARS-CoV-induced eIF2 alpha phosphorylation. Pretreatment of cells with beta interferon prior to SARS-CoV infection led to a significant decrease in PERK activation, eIF2 alpha phosphorylation, and SARS-CoV replication. The various effects of beta interferon treatment were found to function independently on the expression of PKR. Our results show that SARS-CoV infection activates PKR and PERK, leading to sustained eIF2 alpha phosphorylation. However, virus replication was not impaired by these events, suggesting that SARS-CoV possesses a mechanism to overcome the inhibitory effects of phosphorylated eIF2 alpha on viral mRNA translation. Furthermore, our data suggest that viral activation of PKR can lead to apoptosis via a pathway that is independent of eIF2 alpha phosphorylation.

Harvard Citation style: Krähling, V., Stein, D., Spiegel, M., Weber, F. and Mühlberger, E. (2009) Severe Acute Respiratory Syndrome Coronavirus Triggers Apoptosis via Protein Kinase R but Is Resistant to Its Antiviral Activity, Journal of Virology, 83(5), pp. 2298-2309. https://doi.org/10.1128/JVI.01245-08

APA Citation style: Krähling, V., Stein, D., Spiegel, M., Weber, F., & Mühlberger, E. (2009). Severe Acute Respiratory Syndrome Coronavirus Triggers Apoptosis via Protein Kinase R but Is Resistant to Its Antiviral Activity. Journal of Virology. 83(5), 2298-2309. https://doi.org/10.1128/JVI.01245-08