The nucleotide sequence of the human parainfluenza type 1 (Pl1) virus nucleoprotein (NP) gene was determined from cDNA clones of the mRNA. A cDNA clone, 4-31, containing a 1.7-kb insert, was identified as a Pl1 NP-specific clone by partial nucleotide sequence analysis and sequence comparison with Sendai virus (SV) NP. Using a vaccinia virus transient expression system, a polypeptide with electrophoretic mobility similar to that of Pl1 NP was synthesized from this clone, which reacted specifically with both polyclonal and monoclonal antibodies against Pl1 virus and Pl1 NP, respectively. The complete nucleotide sequence of this clone was determined and was found to contain a single open reading frame that can encode a protein of 524 amino acids with a predicted molecular weight of 57,547. Comparison of the amino acid sequence of Pl1 NP with that of other paramyxoviruses showed that two conserved amino acid sequences found within other paramyxoviruses are also present in Pl1 NP. Although Pl1 and SV showed a high sequence homology, approximately 100 amino acids at the C-terminal region were highly divergent as found also among other paramyxoviruses.
Amino Acid Sequence Animals