title: [Characterization of internal genes of two strains of influenza A (H9N2) virus isolated from men].
abstract: BACKGROUND
  To understand the characteristics of internal genes of two strains of influenza A(H9N2) virus isolated from men and on the basis of these to reveal the origin of these two strains of influenza A(H9N2)virus.
  
  
  METHODS
  The target gene was amplified by RT-PCR,the PCR product was ligated with P GEM-T Vector (Promega Company, USA) at 4 degrees, the recombined plasmid was transferred into dH5a bacteria, and the positive colonies were selected and identified with restriction enzyme. Afterwards, they were sent to Liu He Tong Company in Beijing for nucleotide sequencing. Finally, phylogenetic analysis of the sequencing data was performed with MegAlign (version 1.03)and Editseq (Version 3.69) softwares.
  
  
  RESULTS
  Internal genes of the two strains of H9N2 virus were G9 lineage. There was a slight difference in nucleotide sequence in PA gene between the two strains, whereas another five gene segments were identical to each other.
  
  
  CONCLUSIONS
  The genomes of the two strains of influenza A(H9N2)virus were G9 lineage.They were transmitted to men separately from different avian sources with different characteristics of gene of influenza A(H9N2) virus, respectively.
authors.affiliation: Department of Influenza, National Institute of Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100052, China.
authors.forename: Yuan-ji
authors.initials: YJ
authors.lastname: Guo
authors.forename: Le-ying
authors.initials: LY
authors.lastname: Wen
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Jun-feng
authors.initials: JF
authors.lastname: Guo
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zi
authors.initials: Z
authors.lastname: Li
mesh_terms: D000818:Animals; D002642:Chick Embryo; D002681:China; D006801:Humans; D053127:Influenza A Virus, H9N2 Subtype / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D007251:Influenza, Human / Q000821:virology*; D010802:Phylogeny; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D014764:Viral Proteins