ABSTRACT: In the second half of 2005, a large-scale outbreak of influenza in poultry and wild birds was caused by a highly pathogenic
H5N1 influenza virus in Russia. The level of pathogenicity is a polygenic trait, and most individual genes contribute to the
influenza A virus pathogenicity in birds, animals, and humans. The full-length nucleotide sequences were determined for H5N1
strains isolated in the Kurgan region (Western Siberia). The structure of viral proteins was analyzed using the deduced amino
acid sequences. The receptor-binding site of hemagglutinin (HA) in strains A/chicken/Kurgan/05/2005 and A/duck/Kurgan/08/2005
was typical for avian influenza viruses and contained Glu and Gly at positions 226 and 228, respectively. The structure of
the basic amino acid cluster located within the HA cleavage site was identical in all isolates: QGERRRKKR. According to the
neuraminidase structure, all H5N1 isolates from the Kurgan region were assigned to the Z genotype. Amino acid residues typical
for the avian influenza virus were revealed in 30 out of 32 positions of M1, M2, NP, PA, and PB2, determining the host range
specificity. One of the strains contained Lys at position 627 of PB2. Isolates from the Kurgan region were shown to have a
remantadine-sensitive genotype. Both strains contained Glu at position 92 of NS1, indicating that the virus is interferon-resistant.
Phylogenetic analysis related the Kurgan isolates to subclade 2 of clade 2 of highly pathogenic H5N1 influenza viruses.
Key wordsinfluenza virus A (H5N1)–sequencing–avian influenza–phylogeny
Molecular Biology 04/2012; 42(1):70-78. · 0.66 Impact Factor