Abstract:

【Objective】 The molecular characterization of PB1-F2 gene of chicken H9N2 subtype avian influenza viruses(AIVs) isolated from China was analyzed and the prevalence of the PB1-F2 genes of influenza A viruses (IAVs) prevailed in China was further investigated. 【Method】 Fourteen H9N2 viruses were isolated from sick chickens in China from 1998 to 2008. The sequences of the PB1-F2 genes of these isolates were determined by RT-PCR and sequencing. Then, 337 PB1 genes of IAVs derived from avian (H5N1, H9N2 subtype), pig (H5N1, H9N2, H1N1 and H3N2 subtype) and human beings (H5N1, H9N2, H1N1 and H3N2 subtype) in China were downloaded from GenBank database and analyzed using molecular biological software. 【Result】 Phylogenic inference drawn from PB1-F2 sequences of the above IAVs showed six distinct clusters. The deduced sequences of PB1-F2 proteins have multifold lengths and the ratio of PB1-F2 genes encoding full-length PB1-F2 protein differed in the HA subtype and host origin of IAV isolates. 【Conclusion】 Through this study, the molecular epidemiologic characteristics of PB1-F2 gene of IAVs in China was illuminated, thus providing a basic foundation of PB1-F2 gene function research in the infection process of IAVs.

Key words: influenza A virus, avian influenza virus, PB1-F2 gene, evolution analysis