The Accessory Protein ORF3 Contributes to Porcine Epidemic Diarrhea Virus Replication by Direct Binding to the Spike Protein

Viruses

Qigai He¹  Challika Kaewborisuth²  Anan Jongkaewwattana² 

[1] State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China;Virology and Cell Technology Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathumthani 12120, Thailand;

关键词: porcine epidemic diarrhea virus;    accessory protein ORF3;    spike protein;    subcellular localization;    virus replication;   

DOI  :  10.3390/v10080399

来源: DOAJ

【 摘 要 】

The porcine epidemic diarrhea virus (PEDV) is an important swine pathogen responsible for severe watery diarrhea, particularly in neonatal piglets. Despite extensive studies performed to elucidate the function of several viral proteins, the contribution of an accessory protein ORF3 in PEDV replication is still largely unknown. Here, we constructed expression plasmids as well as recombinant PEDV carrying myc-tagged ORF3 to assess their expression and subcellular localization in both transfected and infected cells. In PEDV-infected cells, ORF3 was predominantly localized in the cytoplasm, partially in the endoplasmic reticulum (ER) and the Golgi apparatus (Golgi). Interestingly, ORF3 with the N-terminal Flag tag was also detected on the cell surface concomitant with the spike (S) protein as determined by flow cytometry and confocal microscopy. ORF3 and S proteins were also co-localized at perinuclear compartments and in the vesicle-like structures in transfected and infected cells. We also demonstrated that both full-length and naturally truncated ORF3 proteins could interact with the S protein but with different binding affinity, which correlate with the ability of the protein to regulate virus replication in cell culture. Collectively, our results underscore the unprecedented role of the ORF3, which involves the interaction of ORF3 with S and, possibly, other structural protein during PEDV replication.

【 授权许可】

Unknown