The nucleotide and predicted amino acid sequence of the attachment protein of canine distemper virus
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J Kövamees1, M Blixenkrone-Möller, E Norrby
1Department of Virology, School of Medicine, Karolinska Institute, Stockholm, Sweden.
Abstract:
The nucleotide sequence of the gene coding for the attachment protein of the Convac strain of the canine distemper virus (CDV), corresponding to the haemagglutinin (H) gene of measles virus was determined using a mRNA-derived cDNA clone and genomic viral RNA. The mRNA transcribed from the CDV H gene is 1944 nucleotides long excluding the polyadenylated tail. Only one long open reading frame was found comprising nucleotides 21-1841. The predicted protein has a single hydrophobic region which can serve as a membrane anchoring domain. The deduced 607 amino acids would code for a protein of 68,247 Da, to be compared with an approximate protein molecular weight in SDS-PAGE of the glycosylated protein, which is 85,000 Da. The CDV H protein exhibited seven potential N-linked glycosylation sites. These were concentrated to the carboxyterminal part of the CDV H protein and differed markedly from measles virus (MV) and rinderpest virus (RPV) where the potential sites were mostly conserved and located in the amino-terminal half of the proteins. In spite of the differences in amino acid composition of these three H proteins their hydrophilicity/hydrophobicity plots were closely similar with the major hydrophobic region at an identical location. All the 12 cysteine residues found in the CDV H protein were conserved in MV and RPV. The amino acid homology between CDV and MV H protein was 37% and between CDV and RPV H protein 38%. The fact that the corresponding homology between the MV and RPV proteins is almost 60% shows that the evolutionary separation between CDV and RPV occurred at a much earlier time than the separation between RPV and MV.
Insights
The canine distemper virus (CDV) attachment protein gene sequence was determined. Its structure and evolutionary relationship to measles virus (MV) and rinderpest virus (RPV) were analyzed.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- Canine distemper virus (CDV) is a significant pathogen affecting various animal species.
- The attachment (H) protein is crucial for viral entry and is a key determinant of host range and pathogenicity.
- Understanding the CDV H gene provides insights into paramyxovirus evolution.
Purpose of the Study:
- To determine the nucleotide sequence of the CDV H gene.
- To analyze the predicted protein structure, including glycosylation sites and hydrophobic regions.
- To compare the CDV H protein with those of measles virus (MV) and rinderpest virus (RPV) to understand evolutionary relationships.
Main Methods:
- Nucleotide sequencing of the CDV H gene using mRNA-derived cDNA and viral RNA.
- Bioinformatic analysis to predict protein structure, open reading frames, and hydrophilicity/hydrophobicity.
- Amino acid sequence comparison and homology analysis with MV and RPV H proteins.
Main Results:
- The CDV H gene mRNA is 1944 nucleotides long, encoding a 607-amino acid protein.
- The predicted protein contains a single membrane-anchoring hydrophobic region and seven N-linked glycosylation sites concentrated in the carboxy-terminal part.
- Amino acid homology was 37% with MV H protein and 38% with RPV H protein, with conserved cysteine residues and similar hydrophilicity plots.
Conclusions:
- The CDV H protein shares structural similarities with MV and RPV H proteins despite differences in glycosylation site distribution.
- The lower homology between CDV and RPV/MV H proteins suggests an earlier evolutionary divergence of CDV.
- These findings contribute to understanding the molecular basis of CDV infection and paramyxovirus evolution.