Analysis Of The Genome Sequence And Bioinformatics Characterizations Of A Novel Strain Of The H7N9 Influenza A Virus

To understand the genomic features of a novel strain of the avian infuenza virus[A/Changsha/2/2013(H7N9)],the genome sequences of Influenza A virus A/Changsha/2/2013(H7N9)were downloaded online from database of NCBI(The National Center for Biotechnology Information).The characterizations of the genome sequences of the virus were analyzed by bioinformatics software.Phylogenetic tree analysis was conducted by Bioedit and Mega software.The phylogenetic tree of the genome of A/Changsha/2/2013(H7N9)demonstrated that A/Changsha/2/2013(H7N9)virus and all the new H7N9 viruses in 2013 were in a large cluster,and their nucleotide evolutionary distances were closely associated.Phylogenetic tree analyses of the nucleoprotein and nonstructural genes showed two main branches.One branch contained novel H7N9 viruses isolated from avian,human and environmental sources in different regions.The other branch contained three novel H7N9 virus strains isolated from environmental sources in Shanghai.All the phylogenetic trees of the matrix protein,polymerase acidic,polymerase basic protein 1 and polymerase basic protein 2 genes also showed two branches,with each branch including the novel H7N9 virus strains isolated from avian,human and environmental sources in different regions.This suggests that NP,NS,MP,PA,PB1 and PB2 genes of the new H7N9 viruses isolated in 2013 are in different degrees of evolutionary separation.Amino acid sequence of HA and NA protein analyzed by Bioedit software.The results showed that the main functional sites of HA and NA protein of A/Changsha/2/2013(H7N9)were conservative.But there also were amino acid mutations at some sites.Some amino acid deletion or mutation sites might have an impact on the virus virulence and immunogenicity of H7N9 avian infuenza,and may facilitate adaptation of the virus to mammalian hosts and even bind to human receptors.