Fusion protein gene nucleotide sequence similarities, shared antigenic sites and phylogenetic analysis suggest that phocid distemper virus type 2 and canine distemper virus belong to the same virus entity.
Nucleotide sequencing of the fusion protein (F) gene of phocid distemper virus-2 (PDV-2), recently isolated from Baikal seals (Phoca sibirica), revealed an open reading frame (nucleotides 84 to 2075) with two potential in-frame ATG translation initiation codons. We suggest that the second in-frame ATG triplet at positions 264 to 266 initiates the translation, resulting in a protein of 537 amino acid residues with a calculated M(r) of 63,035. The putative F1/F2 cleavage site, located approximately 100 amino acid residues from the N terminus, is identical to those of the F proteins of phocid distemper virus-1 (PDV-1) isolated from European harbour seals (Phoca vitulina) and of canine distemper virus (CDV). A full scale comparison of morbillivirus F genes reveals that the conserved F0 extracellular protein-encoding region contains a large number of non-expressed mutations, suggesting that this part of the protein is under strong functional constraints. Phylogenetic analysis of morbillivirus F gene nucleotide sequences revealed a closer evolutionary relationship between PDV-2 and CDV than between PDV-1 and PDV-2. These data were supported by cross-reactivity patterns of PDV-2 and CDV obtained with monoclonal antibodies to structural proteins of PDV-1 and CDV, and suggest that PDV-2 is a strain of CDV, resulting from a trans-species infection.
Seal Rehabilitation and Research Centre, Pieterburen, The Netherlands.
I K
IK
Visser
R W
RW
van der Heijden
M W
MW
van de Bildt
M J
MJ
Kenter
C
C
Orvell
A D
AD
Osterhaus
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D004217:Distemper Virus, Canine / Q000235:genetics*; D005814:Genes, Viral; D008459:Measles virus / Q000235:genetics*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010252:Paramyxoviridae / Q000235:genetics* / Q000302:isolation & purification; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics; D046048:Seals, Earless; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014760:Viral Fusion Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification
D003062:Codon; D004279:DNA, Viral; D012333:RNA, Messenger; D014760:Viral Fusion Proteins; C076619:F protein, Phocine distemper virus