title: [Studies on the basis of molecular biology of the phase change of influenza A(H1N1) viruses].
abstract: OBJECTIVE
  To reveal the basis of molecular biology of the phase change of influenza A (H1N1) viruses.
  
  
  METHODS
  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 oligodeoxynucleotide primers. Finally, phylogenetic analysis of the sequencing data was performed with MegAlign (Version 1.03) and Editseq (Version 3.69) software.
  
  
  RESULTS
  No special amino acid on HA1 protein molecule determining the influenza A(H1N1) virus with O or D phase feature was found. However, there are differences of amino acid sequences at -2, -7, 130 and 139 positions between H1N1 viruses isolated in or before end after 1995. It is very interesting that since 1995, two different genetic lineages of influenza A (H1N1) virus HA gene have been cocirculating in men in China. One lineage is no any deletion of amino acid on HA1 protein molecule. The other one has a deletion at 130 position. Their amino acid sequences were compared with those of H1N1 viruses isolated before 1995.
  
  
  CONCLUSIONS
  There is no special amino acid on HA1 domain protein molecule determining the influenza A (H1N1) virus with O or D phase feature was found. Since 1995, two distinguished genetic lineages of influenza A H1N1 virus HA gene have been cocirculating in men in China.
authors.affiliation: Institute of Virology, Chinese Academy of Preventive Medicine, Bejing 100052, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Guo
authors.forename: J
authors.initials: J
authors.lastname: Dong
authors.forename: M
authors.initials: M
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000940:Antigenic Variation; D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics; D005814:Genes, Viral / Q000235:genetics*; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D053118:Influenza A Virus, H1N1 Subtype; D009980:Influenza A virus / Q000737:chemistry / Q000145:classification / Q000235:genetics*; D008967:Molecular Biology; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000235:genetics; D017421:Sequence Analysis
chemical_list: D004279:DNA, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D012367:RNA, Viral