Sequence analysis of the genes encoding the nucleocapsid protein and phosphoprotein (P) of phocid distemper virus, and editing of the P gene transcript

1 Institute of Veterinary Microbiology, Laboratory for Virology and Immunology, The Royal Veterinary and Agricultural University, Bülowsvej 13, Frederiksberg C, DK1870, Denmark and 2 Department of Virology, School of Medicine, Karolinska Institute, Stockholm S-105 21, Sweden The nucleotide and deduced amino acid sequences of two genes of phocid distemper virus (PDV) were determined by cDNA cloning and sequencing. The long open reading frame of the gene encoding the nucleocapsid (N) protein is presented. As with other morbilliviruses, the phosphoprotein (P) gene of PDV was found to be located after the 5' end of the N gene and before the 3' end of the matrix protein gene. The P gene was shown to have the capacity to encode three distinct proteins, P, V and C, in analogy to other morbilliviruses. The results presented provide evidence for editing of the PDV P mRNA transcript by insertion of G residues. When the nucleotide and deduced amino acid sequences of the N, P, V and C genes were aligned with corresponding sequences of other established members of the morbillivirus genus, compelling homology was found between PDV and canine distemper virus (CDV), whereas there was markedly less similarity between PDV and measles virus or rinderpest virus. On the basis of the alignments presented, the estimated amino acid sequence similarity between the N and P genes of PDV and CDV was 84% and 76%, respectively. These differences at the genomic level indicate that the viruses are two separate entities. Permanent address: Division of Virology, Indian Veterinary Research Institute, Mukteswar-Kumaon, Nainital 263138, India. Received 19 July 1991; accepted 16 December 1991.