Complete sequence of the major nucleocapsid protein gene of human parainfluenza type 3 virus: comparison with other negative strand viruses.

The sequence of the major nucleocapsid protein (NP) mRNA and its encoded protein were deduced by sequencing a cDNA clone representing the complete mRNA. The cDNA sequence was confirmed by dideoxynucleotide sequencing of purified viral genomic RNA by primer extension using synthetic oligonucleotides. The NP mRNA contains 1,641 nucleotides exclusive of poly(A) and encodes an NP protein of 515 amino acids. Alignment of the human parainfluenza type 3 virus (PF3) NP protein sequence with that of Sendai virus showed that the two proteins shared considerable sequence identity (58.8%). Additional comparisons provided highly significant statistical evidence that the PF3 NP protein sequence is related to those of measles and canine distemper viruses, but there was no evidence of relatedness with the nucleocapsid proteins of respiratory syncytial virus, influenza B virus, or vesicular stomatitis virus.