Author
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Seal, Bruce |
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Submitted to: Functional and Integrative Genomics
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/15/2004 Publication Date: 10/1/2004 Citation: Seal, B.S. 2004. Nucleotide and predicted amino acid sequence analysis of the fusion protein and hemagglutinin-neuraminidase protein genes among Newcastle disease virus isolates. Phylogenetic relationships among the Paramyxovirinae based on attachment glycoprotein sequences. Functional and Integrative Genomics, 4(4):246-257. Interpretive Summary: Highly virulent Newcastle disease virus (NDV) isolates are List A pathogens for commercial poultry, and reports of its isolation among member nations must be made to the Office of International Epizootes (OIE). Two virus surface glycoproteins, the fusion (F) and hemagglutinin-neuraminidase (HN) proteins, play essential roles in NDV attachment to cells during infection. Antibodies to the F or HN are capable of virus neutralization and no full-length sequences are available for these proteins from recently obtained virulent NDV isolates. Consequently, nucleotide and predicted amino acid sequences of the F and HN protein genes for fifteen NDV isolates representing highly virulent viruses from worldwide sources were compared too older virulent isolates and vaccine strains. Basic physical structure of theses viral proteins were maintained among all the isolates with some variation due to substitution of similar amino acids in the proteins of different isolates. One NDV isolate from a Eurasian collared dove had unique changes in its surface glycoproteins that indicated that these birds may have NDV circulating among them that evolve differently from other species. Based on genetic sequences for these proteins, NDV isolates separated into four specific groups representing two vaccine categories and two virulent categories. Virulent viruses found worldwide form a genetically diverse group. However, since the genetic differences have not resulted in major physical changes in the proteins this helps explain why currently utilized vaccines for commercial poultry remain protective against Newcastle disease. Technical Abstract: Highly virulent Newcastle disease virus (NDV) isolates are List A pathogens for commercial poultry, and reports of its isolation among member nations must be made to the Office of International Epizootes (OIE). The virus is classified as a member of the order Mononegalovirales in the family Paramyxoviridae of the subfamily the Paramyxovirinae. Two interactive surface glycoproteins, the fusion (F) and hemagglutinin-neuraminidase (HN) proteins, play essential roles in NDV cell attachment and fusion of cells during infection. Antibodies to the F or HN are capable of virus neutralization and no full-length sequences are available for these genes from recently obtained virulent NDV isolates. Consequently, nucleotide and predicted amino acid sequences of the F and HN protein genes for fifteen NDV isolates representing highly virulent viruses from worldwide sources were cloned and sequenced for comparison too older virulent isolates and vaccine strains. The F protein amino acid sequence was relatively conserved among isolates maintaining the basic predicted physical structure including potential glycosylation sites and C residues for disulfide bonds. The dibasic amino acid motif was present at the cleavage site among more virulent isolates, while the low virulence viruses did not have this sequence. A Eurasian collared dove virus had a K114Q substitution at the F cleavage site unique among NDV isolates. The HN protein predicted physical structure was also maintained among NDV isolates with conserved amino acid substitutions at specific residues. HN protein length for a Eurasion collard dove isolate and a previously reported heat resistant virulent isolate were longer relative to other more recent virulent isolates. Phylogenetically NDV isolates separated into four groups with more recent virulent isolates forming a diverse branch with origins worldwide, while all the avian paramyxoviruses formed their own clade distinct from other members of the Paramyxoviridae. |
