Mapping of putative virulence motifs on infectious salmon anemia virus surface glycoprotein genes.
Infectious salmon anemia virus (ISAV) is classified in the genus Isavirus of the family Orthomyxoviridae. Although virulence variation of ISAV can be demonstrated experimentally in fish, virus strain identification is ambiguous because the correlates of pathogenicity and/or antigenicity of ISAV are not well defined. Thirteen ISAV isolates characterized for their ability to kill fish were used to search for markers of virulence on the virus surface glycoprotein genes; haemagglutinin-esterase (HE) and fusion (F) protein genes. A single amino acid change N(164)D in the putative globular head of the HE protein, and a deletion/insertion of <or=13 aa with the presence of a specific motif (352)FNT(354) in the highly polymorphic region spanning residues (337)V to M(372) in the HE protein stalk, in combination with a specific motif (265)YP(266) very close to the trypsin-cleavage site (267)RA/G(268) of the precursor F(0) protein were correlated with reduced cytopathogenicity and reduced virulence for Atlantic salmon. Phylogenetic analysis suggests that the original ancestral ISAV was virulent. The virulence of the North American genotype has not changed much, whereas the European genotype evolved into two genogroups, the real-European genogroup that is still virulent and the European-in-North America genogroup, which is of lower virulence. A novel phylogenetic software program, backtrack, estimated that the North American and European genotypes diverged between 1879 and 1891, whereas the European-in-North America genogroup diverged from the real-European genogroup between 1976 and 1988. This direction of evolution supports insertion of specific motifs in the HE protein, resulting in ISAV attenuation.
Kibenge
Frederick S B
FSB
Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE C1A 4P3, Canada.
Kibenge
Molly J T
MJT
Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE C1A 4P3, Canada.
Wang
Yingwei
Y
Department of Computer Science and Information Technology, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE C1A 4P3, Canada.
Qian
Biao
B
Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE C1A 4P3, Canada.
Hariharan
Shebel
S
Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PE C1A 4P3, Canada.
McGeachy
Sandi
S
New Brunswick Department of Agriculture and Aquaculture, PO Box 6000, Fredericton, NB E3B 5H1, Canada.
D020816:Amino Acid Motifs / Q000235:genetics / Q000502:physiology; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003588:Cytopathogenic Effect, Viral / Q000235:genetics; D019143:Evolution, Molecular; D005393:Fish Diseases / Q000401:mortality / Q000821:virology; D005843:Geography; D006389:Hemagglutinins, Viral / Q000235:genetics / Q000502:physiology*; D046829:Isavirus / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D017684:Oncorhynchus kisutch; D017686:Oncorhynchus mykiss; D009976:Orthomyxoviridae Infections / Q000401:mortality / Q000662:veterinary / Q000821:virology; D010802:Phylogeny; D020317:Salmo salar; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D017385:Sequence Homology; D014760:Viral Fusion Proteins / Q000235:genetics / Q000502:physiology*; D014774:Virulence
D006389:Hemagglutinins, Viral; D014760:Viral Fusion Proteins; C060814:hemagglutinin esterase