[Complete genome sequence analysis of a newly isolated paramyxovirus Tianjin strain]

Paramyxovirus Tianjin strain is the high-pathogenic virus to primate and might also cause human lower respiratory tract infection. To determine the genome structure, variation features and phylogenetic position, the complete nucleotide sequence of paramyxovirus Tianjin strain was analyzed. The homology comparison and phylogenetic analysis of the nucleotide and the deduced amino acid sequences among paramyxovirus Tianjin strain and the 28 strains in seven genera and the 7 unclassified viruses of Paramyxoviridae were performed. The results suggested that Tianjin strain is a member of the Respirovirus genus in the Paramyxovirinae, Paramyxoviridae and has the closest relationship to Sendai virus. Its genome length and composition are similar to the previously published Sendai virus except one extra glutamic acid residue increasing at the C terminus of Large protein due to the genomic RNA mutation at position A15240C. 440 unique nucleotide variations of Tianjin strain lead to 110 amino acid residue changes, making it differed from any other Sendai viruses. The phylogenetic analysis reveals paramyxovirus Tianjin strain doesn't belong to any of the three known evolution lineages of Sendai viruses and locates at a separate evolution branch. The obvious distinctions of genome nucleotide sequence, host tropism and pathogenicity suggest that paramyxovirus Tianjin strain might represent a novel genotype of Sendai virus.