Temporal and subcellular localization of infectious pancreatic necrosis virus structural proteins.

The temporal subcellular localization of the structural proteins VP2 and VP3 of infectious pancreatic necrosis virus was analyzed with monoclonal antibodies conjugated with fluorochromes. Early in the infection both proteins were colocalized in the cytosol, at later times, VP2 was visualized as inclusion bodies around the nuclei of the cells and, sometimes, it was found in elongated tubular structures that might correspond to the type I tubules seen in cells infected with another Birnavirus. As VP2 is a glycosylated protein we determined its subcellular localization compared with that of ER and Golgi probes. These results suggest that VP2 is glycosylated freely in the cytoplasm.