Epitopes and nuclear localization analyses of canine distemper virus nucleocapsid protein by expression of its deletion mutants

A series of nucleocapsid protein (NP)-deleted genes of the Onderstepoort st rain was constructed in order to locate antigenic regions of the NP of cani ne distemper virus. The expression of proteins from 5'-deleted NP genes was examined in COS-7 cells by indirect immunofluorescence assay using three m onoclonal antibodies (MAbs), c-5, f-5 and h-6, and a rabbit serum against N P. These MAbs reacted with two regions of NP. Amino acid residues from 1 to 80, and 337-358, were necessary and sufficient for formation of the epitop es identified by MAbs f-5 and h-6, and c-5, respectively. The proteins tran slated from intact or 3'-deleted genes were found to be localized in the nu clei of COS-7 cells, whereas the proteins from the 5'-deleted genes were ma inly detected in the cytoplasm. These results suggested that 80 amino acid residues at the N-terminus are required for transportation of NP into the n ucleus. (C) 1999 Elsevier Science B.V. All rights reserved.