Subcellular localization of the porcine deltacoronavirus nucleocapsid protein

Ding, Zhen; Luo, Suxian; Gong, Wang; Wang, Leyi; Ding, Nengshui; Chen, Jun; Chen, Jiajia; Wang, Ting; Ye, Yu; Song, Deping; Kong, Lingbao; Zhang, Jinghua; Tang, Yuxing

Porcine deltacoronavirus (PDCoV) has been recently identified as an emerging enteropathogenic coronavirus that mainly infects newborn piglets and causes enteritis, diarrhea and high mortality. Although coronavirus N proteins have multifarious activities, the subcellular localization of the PDCoV N protein is still unknown. Here, we produced mouse monoclonal antibodies against the PDCoV N protein. Experiments using anti-haemagglutinin antibodies and these monoclonal antibodies revealed that the PDCoV N protein is shuttled into the nucleolus in both ectopic PDCoV N-expressing cells and PDCoV-infected cells. The results of deletion mutagenesis experiments demonstrated that the predicted nucleolar localization signal at amino acids 295–318 is critical for nucleolar localization. Cumulatively, our study yielded a monoclonal antibody against the PDCoV N protein and revealed a mechanism by which the PDCoV N protein translocated into the nucleolus. The tolls and findings from this work will facilitate further investigations on the functions of the PDCoV N protein.