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Sequencing analyses and comparison of parainfluenza virus type 4A and 4B NP protein genes
Abstract:
The nucleotide sequences of the cDNA copies of the mRNA coding for the nucleocapsid proteins (NPs) of human parainfluenza viruses type 4A (PIV-4A) and type 4B (PIV-4B) were determined. The copy of PIV-4A NP mRNA contained 1885 nucleotides encoding a protein with a calculated molecular weight of 62,561. The same number of amino acids with a similar molecular weight (62,425) were predicted for the PIV-4B NP protein. Comparisons on the nucleotide sequence and the amino acid sequence of NP protein between these two subtypes revealed extensive homologies in the nucleotide sequence (87%) and in the amino acid sequence (93%). Furthermore, a conserved region with about 100 amino acids was observed between PIV-4s and other paramyxoviruses, Newcastle disease virus (NDV), Sendai virus, mumps virus (MuV), PIV-3, BPIV-3, measles virus (MV), and canine distemper virus (CDV), indicating a common ancestor for these nine viruses. Our data also indicated that the PIV-4 NP proteins were more closely related to MuV and NDV than to other parainfluenza viruses, PIV-3, BPIV-3, and Sendai virus. Interestingly, the NP protein homology between PIV-4s and the morbillivirus group, MV and CDV, was slightly higher than that between PIV-4s and the parainfluenza viruses, PIV-3, BPIV-3, and Sendai virus.
Insights
Human parainfluenza viruses 4A and 4B (PIV-4A and PIV-4B) nucleocapsid proteins show high sequence homology. These PIV-4 NPs are closely related to other paramyxoviruses, suggesting a common viral ancestor.
Area of Science:
- Virology
- Molecular Biology
- Genomics
Background:
- Human parainfluenza viruses (HPIVs) are significant respiratory pathogens.
- Understanding the genetic diversity and evolutionary relationships of HPIV subtypes is crucial for disease control.
- Nucleocapsid protein (NP) is a key component of the paramyxovirus genome and plays a vital role in viral replication.
Purpose of the Study:
- To determine and compare the nucleotide sequences of the nucleocapsid protein (NP) genes of human parainfluenza virus type 4A (PIV-4A) and type 4B (PIV-4B).
- To analyze the sequence homology between PIV-4A and PIV-4B NP proteins.
- To investigate the evolutionary relationships of PIV-4 NPs with other members of the Paramyxoviridae family.
Main Methods:
- Nucleotide sequencing of cDNA copies of PIV-4A and PIV-4B NP mRNA.
- Bioinformatic analysis of nucleotide and amino acid sequences.
- Comparative sequence analysis with NP genes from other paramyxoviruses.
Main Results:
- The PIV-4A NP mRNA contained 1885 nucleotides, encoding a protein of 62,561 Da.
- PIV-4B NP protein had a similar molecular weight (62,425 Da) and amino acid length.
- Extensive homologies were found between PIV-4A and PIV-4B NP sequences (87% nucleotide, 93% amino acid).
- A conserved region of approximately 100 amino acids was identified in NP proteins across nine different paramyxoviruses, including PIV-4s, Newcastle disease virus (NDV), Sendai virus, mumps virus (MuV), PIV-3, BPIV-3, measles virus (MV), and canine distemper virus (CDV).
- PIV-4 NPs showed closer evolutionary relationships to MuV and NDV than to PIV-3, BPIV-3, or Sendai virus.
- PIV-4 NPs exhibited slightly higher homology to morbilliviruses (MV, CDV) than to other parainfluenza viruses.
Conclusions:
- PIV-4A and PIV-4B NP proteins are highly conserved, indicating a close relationship between these two subtypes.
- The identified conserved region in NP proteins supports the hypothesis of a common ancestor for the studied paramyxoviruses.
- The phylogenetic analysis suggests distinct evolutionary paths within the Paramyxoviridae family, with PIV-4 NPs occupying a specific position relative to other genera.