Isolation And Analysis The Sequences Of A/Sw/GX/06 (H1N2) Swine Influenza Virus

In this study,a swine influenza virus was isolated from the lung tissues of pigs in Guangxi.The subtype of the isolated was identified by RT-PCR techniques.In an effort to determine the genetic characterization and probable origin,the eight genes of isolated were cloned and genetically analyzed.The result show that the isolated was H1N2 subtype swine influenza virus and was named as A/Sw/GX/13/06.The analysis of amino acid of HA showed that 8 potential glycosylation sites of A/Sw/GX/13/06 were conserved.The amino acids at receptor-binding site(RBS)190,225,226 and 228 of isolated were N,D,Q and G,respectively,which enable the isolated has the affinity of the SAα2,3Gal and SAα2,6Gal.it means that A/Sw/GX/13/06 may have the potential to infect the avian and mammals.The amino acid sequence at the HA cleavage site of isolated is PSIQSR↓G,which is consist with the characteristic of low pathogenicial influenza virus.In the NA gene,the glycosylation sites at 61,70,86,146,200,234,402 were conserved,but it lost a potential glycosylation site because S mutated to R.Whether the lost of potetial glycosylation site will affect the biological character of the virus,it need futher study.Phylogenetic analysis showed that A/Sw/GX/13/06 was a human/swine/avian H1N2 virus,The HA,NP,M and NS genes of A/Sw/GX/13/06 were most closely related to genes from the classical swine H1N1 influenza virus lineage.NA and PB1 genes were most closely related to the corresponding genes from the human influenza H3N2 virus lineage.The remaining two genes were most closely related to the genes from avian influenza virus lineage.and closely related to H1N2 viruse A/Swine/Indiana/P12439/00(H1N2)isolated from pigs in United States between 1999 and 2001...