Middle East Respiratory Syndrome Coronavirus Nucleocapsid Protein Suppresses Type I and Type III Interferon Induction by Targeting RIG-I Signaling.

Type I and type III interferons (IFNs) are the frontline of antiviral defense mechanisms that trigger hundreds of downstream antiviral genes. In this study, we observed that MERS-CoV nucleocapsid (N) protein suppresses type I and type III IFN gene expression. The N protein suppresses Sendai virus-induced IFN-β and IFN-λ1 by reducing their promoter activity and mRNA levels, as well as downstream IFN-stimulated genes (ISGs).

Nucleocapsid protein-dependent assembly of the RNA packaging signal of Middle East respiratory syndrome coronavirus.

Background: Middle East respiratory syndrome coronavirus (MERS-CoV) consists of a positive-sense, single-stranded RNA genome and four structural proteins: the spike, envelope, membrane, and nucleocapsid protein. The assembly of the viral genome into virus particles involves viral structural proteins and is believed to be mediated through recognition of specific sequences and RNA structures of the viral genome.

Methods And Results: A culture system for the production of MERS coronavirus-like particles (MERS VLPs) was determined and established by electron microscopy and the detection of coexpressed viral structural proteins.