Narayanasamy Elango

The mumps virus nucleocapsid mRNA sequence and homology among the Paramyxoviridae proteins

The nucleotide sequence of mumps virus nucleocapsid protein (NP) mRNA has been determined from two overlapping cDNA clones and confirmed by partial sequencing of the mRNA and the genome. The mRNA contains 1844 nucleotides excluding poly(A) and encodes a protein of 553 amino acids with a calculated molecular weight of 61,792. A comparison of the mumps virus nucleocapsid protein sequence with that of other paramyxoviruses revealed a moderate degree of homology (33.1%) with the Newcastle disease virus (NDV) only. The nucleocapsid proteins of all paramyxoviruses studied to date, excluding that of the genus pneumovirus, have a conserved sequence of six amino acids (Ser-Tyr-Ala-Met-Gly-Val) except that of NDV which has a mismatch of two amino acids (Ser-Phe-Ala-Met-Gly-Met) in that sequence. In addition, there is another conserved region of seven amino acids (Phe-Ala-Pro-Gly-X-Tyr-Pro) in the nucleocapsid proteins of mumps virus, Sendai virus and parainfluenza virus type 3. The nucleocapsid proteins of measles virus and canine distemper virus (CDV) also have this conserved region but with three conservative amino acid changes.

Complete nucleotide sequence of the hemagglutinin-neuraminidase (HN) mRNA of mumps virus and comparison of paramyxovirus HN proteins.

The complete nucleotide sequence of the hemagglutinin-neuraminidase protein (HN) mRNA of the virulent SBL-1 strain of mumps virus has been determined. The mRNA contains 1887 nucleotides excluding the poly(A). The protein encoded by the mRNA has 582 amino acids and a membrane anchorage domain near the amino terminus. The calculated molecular mass (64 kDa) of the protein is in good agreement with that of the unglycosylated HN protein (63 kDa) identified in tunicamycin treated mumps virus infected cells (Herrler and Compans, 1983). The predicted sequence has nine potential N-glycosylation sites out of which two contain a cysteine residue and one has a proline residue as the variable amino acid X in the glycosylation site (Asn-X-Ser or Asn-X-Thr) and therefore, may not be utilized. One potential glycosylation site is in the cytoplasmic region which may not also be glycosylated. Comparison of the mumps HN protein sequence with the HN protein sequences of Sendai virus, simian-virus 5 (SV5), parainfluenza virus type 3 and Newcastle disease virus (NDV) shows two major homology regions, one region near the middle of the protein and the other in the second half of the molecule. In terms of percentage amino acid homology, the HN proteins of mumps virus, SV5 and NDV are closely related to each other but distinct from Sendai virus and parainfluenza virus type 3 HN proteins.

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.

Complete nucleotide sequence of the matrix protein mRNA of mumps virus

The complete nucleotide sequence of the mumps virus membrane protein or matrix protein (M) has been determined by sequencing cDNA clones and confirmed by partially sequencing the M mRNA and the genome. The mRNA is 1248 nucleotides long excluding the poly(A) and encodes a protein of 375 amino acids. The molecular weight (38,670), deduced from the amino acid sequence, is in agreement with the molecular weight of the viral M protein estimated by polyacrylamide gel electrophoresis (39-40 kDa). The mumps virus M protein shows 23-27% homology with M proteins of Newcastle disease virus (NDV), measles virus, canine distemper virus (CDV), parainfluenza virus type 3, and Sendai virus, respectively. A comparison of the M protein sequences of the above six paramyxoviruses did not reveal any conserved area of homology common among all paramyxovirus M proteins.

The mumps virus fusion protein mRNA sequence and homology among the paramyxoviridae proteins

The complete nucleotide sequence of the fusion protein (F) mRNA of the virulent SBL-1 strain of mumps virus has been determined by sequencing cDNA clones and mRNA and confirmed by partially sequencing the genomic RNA. The mRNA was 1721 nucleotides long excluding the poly(A) sequence and had one long open reading frame which encoded a protein of 538 amino acids with a calculated Mr of 58,791. The predicted amino acid sequence had a proteolytic cleavage/activation site, Arg Arg His Lys Arg, cleavage at which yields proteins F2 and F1. The uncleaved protein contained three highly hydrophobic regions: (i) the amino-terminal signal peptide, (ii) the amino-terminal region of F1 and (iii) the carboxy-terminal membrane anchorage domain. There were seven potential N-glycosylation sites, two in F2 and five in F1. Comparison of the virulent strain F protein sequence with that of an avirulent strain of mumps virus showed a difference of 14 amino acids. Among paramyxoviruses, mumps virus fusion protein shows the highest degree of homology with the fusion proteins of simian virus 5 and Newcastle disease virus.

Sequence analysis of the mumps virus mRNA encoding the P protein

The nucleotide sequence of the mumps virus phospho- or polymerase-associated (P) protein mRNA has been determined by sequencing a full-length cDNA clone and confirmed by partially sequencing the mRNA and the genome. The mRNA contains 1311 nucleotides excluding the poly(A) and encodes a protein of 390 amino acids with a calculated molecular weight of 41,574. Three small polypeptides were seen in in vitro translation of viral mRNA and hybrid-selected P mRNA, possibly representing internal initiation in the same reading frame of the P protein. A second overlapping reading frame is predicted from the sequence which has a capacity to code for two polypeptides of 56 and 34 amino acids, respectively. Whether these two polypeptides are expressed in infected cells is not known. Comparison of the P protein sequence with that of Sendai virus, measles virus, parainfluenza virus type 3, and canine distemper virus (CDV) showed no distinct homology but comparison with the P protein of Newcastle disease virus (NDV) showed 25.6% homology.