Nucleocapsid Proteins From Other Swine Enteric Coronaviruses Differentially Modulate PEDV Replication

Virology
Volume 540, 15 January 2020, Pages 45-56

Sungsuwan, S.; Jongkaewwattana, A.; Jaru-Ampornpan, P.

Abstract

Porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV) and porcine deltacoronavirus (PDCoV) share tropism for swine intestinal epithelial cells. Whether mixing of viral components during co-infection alters pathogenic outcomes or viral replication is not known. In this study, we investigated how different coronavirus nucleocapsid (CoV N) proteins interact and affect PEDV replication. We found that PDCoV N and TGEV N can competitively interact with PEDV N. However, the presence of PDCoV or TGEV N led to very different outcomes on PEDV replication. While PDCoV N significantly suppresses PEDV replication, overexpression of TGEV N, like that of PEDV N, increases production of PEDV RNA and virions. Despite partial interchangeability in nucleocapsid oligomerization and viral RNA synthesis, endogenous PEDV N cannot be replaced in the production of infectious PEDV particles. Results from this study give insights into functional compatibilities and evolutionary relationship between CoV viral proteins during viral co-infection and co-evolution.

Keywords

Porcine epidemic diarrhea virus, Swine coronavirus, Nucleocapsid protein

Bovine coronavirus I protein synthesis follows ribosomal scanning on the bicistronic N mRNA

Virus Research
Volume 48, Issue 1, April 1997, Pages 101-105

Savithra D.Senanayake, David A.Brian

Abstract

The mRNA encoding the 49-kDa nucleocapsid protein (N) of the bovine coronavirus is bicistronic. A 23-kDa protein, termed the I protein for the ‘internal’ open reading frame (ORF), is also synthesized but in the +1 reading frame beginning 61 nt downstream of the N start codon. Sequences flanking the N and I start codons suggest that the I ORF might be accessed by scanning ribosomes passing over the N start codon. Here we test this idea and demonstrate with translation studies both in vitro and in vivo that the I protein is synthesized according to the leaky scanning model for initiation of translation on the subgenomic N mRNA molecule.

Keywords

Coronavirus bicistronic N mRNA, Nucleocapsid protein, Ribosomal scanning