SARS coronavirus 8b reduces viral replication by down-regulating E via an ubiquitin-independent proteasome pathway.

Choong-Tat Keng (1) , Sara Akerström (2, 3) , Cynthia Sau-Wai Leung (4) , Leo L M Poon (4) , J S Malik Peiris (4, 5) , Ali Mirazimi (2, 3) , Yee-Joo Tan (1, 6)

1 Collaborative Anti-Viral Research Group
2 Center for Microbiological Preparedness
3 Department of Microbiology, Tumor and Cell Biology
4 Department of Microbiology [HKU]
5 Centre de recherche Université de Hong-Kong-Pasteur
6 Department of Microbiology

The severe acute respiratory syndrome coronavirus (SARS-CoV) 8b protein, which is not expressed by other known coronaviruses, can down-regulate the envelope (E) protein via a proteasome-dependent pathway. Here, we showed that the down-regulation of E is not dependent on the lysine residues on 8b and the reduction of polyubiquitination of E mutants is not correlated with their down-regulation by 8b, suggesting an ubiquitin-independent proteasome pathway is involved. A time-course study revealed that 8b was expressed at late-stages of SARS-CoV infection. By using Vero E6 cells stably expressing green fluorescence protein-tagged 8b, ectopic expression of 8b was shown to significantly reduce the production of progeny virus and down-regulate E expression. Taken together, these results suggest that 8b negatively modulates virus replication by down-regulating E via an ubiquitin-independent proteasome pathway.

Domains: Virology

Choong-Tat Keng, Sara Akerström, Cynthia Sau-Wai Leung, Leo L M Poon, J S Malik Peiris, et al.. SARS coronavirus 8b reduces viral replication by down-regulating E via an ubiquitin-independent proteasome pathway.. Microbes and Infection, 2011, 13 (2), pp.179-88. ⟨10.1016/j.micinf.2010.10.017⟩. ⟨pasteur-00588905⟩