MERS coronavirus nsp1 participates in an efficient propagation through a specific interaction with viral RNA

MERS-CoV is the only lethal human CoV still endemic in the Arabian Peninsula and neither vaccine nor therapeutics against MERS-CoV infection is available. The nspl of CoV is thought to be a major virulence factor because it suppresses protein synthesis through the degradation of host mRNA. In contrast, viral RNA circumvents the nspl-mediated translational shutoff for an efficient propagation. In this study, we identified amino acid residue in MERS-CoV nspl that differ from those of SARS-CoV nspl, and that appear to be crucial for circumventing the translational shutoff. In addition, reverse genetics analysis suggested the presence of a cisacting element at the 5 '-terminus of the nspl-coding region, which contributes to the specific recognition of viral RNA that is required for an efficient viral replication. Our results suggest the CoVs share a common mechanism for circumventing the nsp 1-mediated translational shutoff.