The complete nucleotide sequence of the JS strain of human parainfluenza virus type 3: comparison with the...

The nucleotide sequence of the JS strain of human parainfluenza virus type 3 (PIV3) was determined from a series of 14 overlapping cDNA clones and was compared to that of the previously sequenced prototype PIV3 strain, Wash/47885/57 (Galinski, 1991). Overall, there were 630 (4%) nucleotide differences between the two viruses. 15462 nucleotides comprised the JS genome in contrast to 15463 which constituted the genome of the prototype virus. This was accounted for by a single nucleotide deletion in the 5' non-coding region of the JS phosphoprotein gene. Four nucleotide substitutions were found in the leader region at the 3' end of the viral genome at positions 24, 28, 42 and 45, whereas no differences were found in the 44 base trailer region. All of the transcription start and stop signals and intergenic sequences were conserved between the two viruses with the exception of the transcription stop signal of the matrix (M) gene where there was a nucleotide transposition between bases 7 and 8. A comparison of all of the nucleotide differences in the 3' and 5' non-coding regions of each gene showed a variability of 9.8% and 10.5%, respectively. The 3' non-coding regions of the nucleocapsid (NP) and M genes were completely conserved in contrast to the polymerase (L) gene in which 25% of the nucleotides were different. Differences were observed in the 5' non-coding regions of each gene and ranged from 5.9% for the hemagglutinin neuraminidase (HN) gene to 14.6% for the M gene. An analysis of the amino acid differences in each open reading frame revealed that of all the genes, the coding region of the M gene was the most highly conserved (1.1% amino acid variability), while the phosphoprotein (P) gene was the most variable (5.8% amino acid variability). As these two viruses are wild type strains, these differences in nucleotide and amino acid sequence are compatible with efficient replication in vivo.