Accessory proteins of SARS-CoV and other coronaviruses

Highlights

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  The SARS-CoV genome encodes eight accessory proteins; none is essential for RNA replication.

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  Several appear to be involved in virus–host interactions and to influence the pathogenicity of the virus.

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  Some of these accessory proteins modulate the interferon pathway and the production of pro-inflammatory cytokines.

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  Five of the accessory proteins are incorporated into virions as minor structural proteins.

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  Other coronaviruses including MERS-CoV also encode accessory proteins.

Abstract

The huge RNA genome of SARS coronavirus comprises a number of open reading frames that code for a total of eight accessory proteins. Although none of these are essential for virus replication, some appear to have a role in virus pathogenesis. Notably, some SARS-CoV accessory proteins have been shown to modulate the interferon signaling pathways and the production of pro-inflammatory cytokines. The structural information on these proteins is also limited, with only two (p7a and p9b) having their structures determined by X-ray crystallography. This review makes an attempt to summarize the published knowledge on SARS-CoV accessory proteins, with an emphasis on their involvement in virus–host interaction. The accessory proteins of other coronaviruses are also briefly discussed. This paper forms part of a series of invited articles in Antiviral Research on “From SARS to MERS: 10 years of research on highly pathogenic human coronaviruses” (see Introduction by Hilgenfeld and Peiris (2013)).