Genetic analysis of NA gene of influenza virus subtype A1 isolates in Zhejiang province from 2005 to 2009

Objective:To analyze the genetic characteristics,variation and evolution of NA gene of influenza virus subtype A1 isolates in Zhejiang province from 2005 to 2009.Methods:The NA gene of influenza virus subtype A1 isolates in Zhejiang province from 2005 to 2009 were sequenced,the molecular and evolution characterization of these virus strains were analyzed by BioEdit and Mega 3.0 bioinformatics software.Results:NA regions of all the isolates were all 1278 bp,encoding protein of 426 amino acids.Isolates shared amino acid homology is 96.0%～99.1% in NA regions.During the 5 years 4 to 10 amino acids on NA region were substituted respectively,but phylogenetic analysis showed that there is no absolutely different branches.Additionally,all the isolates have 7 N-linked glyeosylation sites in NA region,with no significant divergences.Conclusion: There is a certain antigenic variation on NA gene of influenza virus subtype A1 in Zhejiang province from 2005 to 2009.More attention should be paid to divergence of NA regions of influenza virus owning to the significant effect to influenza epidemic.