Study on the origin of influenza A(H1N2) virus HA and NA genes
Qi Junlin, WANG Min, DONG Jie, et al.
（Institute of Virology, Chinese Academy of Preventive Medicine, Beijing 100052）
【Abstract】 Objective To determine the origins of the HA and NA genes of new subtype (H1N2) of influenza A virus. Methods Virus was amplified in embryonated chicken eggs, then virion RNA was transcribed into cDNA by reverse transcriptase, cDNA amplified by PCR, the products of PCR were purified. Afterward, RNA sequence analysis was performed by the dideoxynucleotide chain termination method, using synthetic oligodideoxynucleotide primers. Finally, phylogenetic analysis of the sequencing data was performed with MegAlign (Version 1.03) and Editseq (Version 3.69) softwares. Results The homology of amino acid sequences of protein molecules on HA1 domains when compared, with A/PR/8/34(H1N1) and A/Guangdong/6/91(H1N1) viruses was 98.2% and 99.4%, respectively. The homology of amino acid sequences of NA protein molecules between the novel reassortant and H1N1 virus was only 83.4%, but the homology of those between H1N2 strain and H3N2 virus circulating in men in 1995 was as high as 99.1%. Conclusion The new reassortant(H1N2) virus HA gene was derived from A/PR/8/34(H1N1) like virus, but its NA gene was derived from H3N2 virus circulating in men in 1995.
【Key words】 Influenza A virus,human; Haemagglutinin; Neuraminidase; Genes
Fig.1 Deduced amino acid sequences of the HA gene HA1 region of the three novel H1N2 viruses compared with those of H1N1 and H1N2 viruses
Note:The amino acid sequences of the HA1 protein molecule of all the comparing viruses compared were provided by the National Influenza Center of China. “-”means the essential glycosylation site
Fig.2 Deduced amino acid sequences of the NA genes of the three novel H1N2 viruses compared
with those of previous H1N2 viruses and H3N2 viruses circulating in men recently
Note:the amino acid sequences of the NA protein molecule of previous H1N2 viruses and the H3N2 viruses were provided by the National Influenza Center of China. “-”means the glycosylation site
Fig.3 Phylogenetic tree for the HA1 genes of H1 subtype of influenza A viruses
Horizontal distance is proportional to the numbers of nucleotide differences between branch points. Vertical lines are for spacing. Scale is drawn to show the mutational distances between the viruses
Fig.4 Phylogenetic tree for 15 influenza A (H3N2 or H1N2) virus NA gene sequences
Horizontal lines are proportional to the numbers of nucleotide differences between branch points. Vertical lines are for spacing. Scale is drawn to show the mutational distances between the viruses
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