Molecular Analysis of the Surface Glycoprotein Genes of an Aquatic Bird Influenza Virus

Several H11N2 subtype of Avian influenza A viruses were isolated from aquatic birds in live bird markets when we surveyed the ecology of the influenza in East China for more than two years and identified by specific RT-PCR.The hemagglutinin(HA) and neuraminidase(NA) genes of one representative virus named A/Duck/Yangzhou/44/2002(H11N2)(DYZ/44/02) was sequenced.The results showed the HA nucleotide sequence of DYZ/44/02 has high identity with Dk/England/56(H11N6) and the NA nucleotide sequence of DYZ/44/02 has more than 95% sequence homology with Dk/Hokkaido/49/98(H9N2).Sequencing and phylogenetic analysis of the N2 NA genes of DYZ/44/02 revealed that the NA gene of DYZ/44/02 has close relationships with that of Ck/Korea/MS96/96-like H9N2 virus and are distinct from those of Ck/Beijing/94(H9N2).The sequence of cleavage site of DYZ/44/02 consists of a single arginine,as is the case with most other hemagglutinins exhibiting low susceptibility to proteolytic activation.