title: [Characterization of HA1 genes of influenza A (H1N1) viruses isolated in Shenzhen City].
abstract: OBJECTIVE
  To understand the molecular bases of intention of influenza virus activity and emergence of "O" phase of influenza A(H1N1) strains in human population in Shenzhen in recently years, and also the evolutionary characterization of influenza A(H1N1) HA1 gene.
  
  
  METHODS
  Virion RNA was transcribed into cDNA by reverse transcriptase, cDNA was amplified by PCR, the products of PCR were purified. Afterward, RNA sequence analysis was performed by the dideoxynucleotide chain termination method using synthetic oligodeoxynucleotide primers. Finally, phylogenetic analysis of the sequencing data was performed with MegAlign (version 1.03) and Editseq (version 3.69) softwares.
  
  
  RESULTS
  Since 1995, there were three different genetic lineages of influenza A(H1N1) virus HA1 gene cocirculating in men in Shenzhen city. Adding one and deleting one of potential glycosylation sites at 54 and 155 positions of amino acid sequences on HA1 protein domain of H1N1 viruses isolated recently was found as compared with those of A/Singapore/6/86(H1N1) virus. Meanwhile, there were some differences of amino acid sequences on HA1 protein molecules among H1N1 viruses tested and A/Singapore/6/86 (H1N1) virus.
  
  
  CONCLUSIONS
  The intention of influenza A(H1N1) virus activity occurred since 1995 was due to emergence of substitution in amino acid sequences, especially the appearance of one addition and one deletion of potential glycosylation sites on their HA1 protein domains, and also was due to occurrence of influenza A(H1N1) virus with feature of "O" phase.
authors.affiliation: Municipal Hygiene and Anti-epidemic Station of Shenzhen, Shenzhen 580020.
authors.forename: X
authors.initials: X
authors.lastname: Cheng
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: He
mesh_terms: D000595:Amino Acid Sequence; D004279:DNA, Viral / Q000032:analysis / Q000235:genetics; D005814:Genes, Viral; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D009980:Influenza A virus / Q000145:classification / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D004279:DNA, Viral