Cloning And Analysis On Gene Phylogenesis And Amino Acid Composition Of PB1-F2 Of AIVs Isolated From Wild Birds

With the recently discovered Influenza A Virus PB1-F2 Protein as the research object, based on the completion of cloning and sequencing PB1-F2 genes of avian influenza viruses (AIV) isolated from 14 wild birds, we performed the analysis on the homology, phylogenetic relationships on these genes and the composition of the coded amino acids. We found the amino acids 37,48,50 of PB1-F2 were arginine(Arg, R), proline(Pro, P), glycine(Gly, G) respectively in a H5N1 high pathogenic avian influenza virus (HPAIV) strain, A/lesser_kestrel/Harbin/194/2007(H5N1), which was different from that of other 13 low pathogenic avian influenza virus (LPAIV) strains, glutamine(Gln, Q), glutamine(Gln, Q) and aspartate(Asp, D) respectively. For further exploring this phenomenon,1061 AIV strains PB1-F2 genetic sequences which download from NCBI Influenza Virus Resource were compared, the results showed that all of the non-H9N2 subtype AIVs:97 Hong Kong H5N1 subtype, the other H5N1 subtype and the other subtypes of AIV were obvious different in the amino acid composition of these sites. Moreover these distinction also presented certain rules and characteristics; H9N2 subtype AIVs:displayed obvious characteristics in temporal and spatial distributions of amino acid composition in these three sites. According to the difference between H9N2 and the other subtypes of AIV, we divided H9N2 subtype AIVs into H5N1-like and Other subtypes-like classes. Genetic phylogenetic analysis showed that PB1-F2 had already formed many distinct phylogenetic clades. Such as H5N1 and Hong Kong strains had a big genetic distance with other AIVs. It seemed to could not be well explaned by genetic stochastic mutation and recombination, its biological significance remains to be further explored.