Upregulation of porcine epidemic diarrhea virus (PEDV) RNA translation by the nucleocapsid protein
Lin Hao, Mario Fragoso-Saavedra, Qiang Liu
Abstract
The role of coronaviral nucleocapsid (N) protein in regulating viral translation remains poorly understood. Here, we showed that the N protein of porcine epidemic diarrhea virus (PEDV) enhances the translation of both virus-like genomic RNA (gRNA) and messenger RNA. Further characterization of the gRNA translation upregulation showed that the N-terminal domain (NTD) + Linker region plays a major role. The stem-loop 1 in the 5′ untranslated region (UTR) and the budged stem loop in the 3′UTR are required for viral translation upregulation by PEDV N protein. The signaling kinase Akt exists in three isoforms. We found that Akt1 enhances viral gRNA translation upregulation by the N protein dependent on its kinase activity. We further showed an interaction between Akt1 and PEDV N, that is abolished by the NTD + Linker region. This suggested that the enhancing effect of Akt1 on translation upregulation by the N protein does not require interaction between these two proteins. • PEDV nucleocapsid (N) protein increases viral gRNA and mRNA translation. • The stem-loop 1 in the 5′UTR has a positive role in viral gRNA translation upregulation by the N protein. • The budged stem loop in the 3′UTR is required for the regulation of viral gRNA translation by PEDV N protein. • Akt1 significantly enhances viral translation upregulation by the N protein. • PEDV N interacts with Akt1 and the interaction is not required for translation upregulation.