title: [Further study on the genetic characteristics of a strain of A/PR/8/34/].
abstract: OBJECTIVE
  Through the test and analysis of nucleotide sequences of seven different RNA segments of the virion to exclude the possibility that A/Guangdong/6/91 (H1N1) strain might be derived from laboratory contamination and to determine how many RNA segments are there with nucleotide sequence difference between A/Guangdong/6/91 (H1N1) and A/PR/8/34 (H1N1) viruses, as well as to determine is A/Guangdong/6/91 virus a reassortant?
  
  
  METHODS
  Virion RNA was transcribed into cDNA by reverse transcriptase, cDNA was amplified by PCR, the products of PCR were purified. Afterward, RNA sequence test was performed by the dideoxynucleotide chain termination method using synthetic oligodeoxynucleotide primers.
  
  
  RESULTS
  There are no nucleotide sequence differences in RNA segments 6 and 7 between A/Guangdong/6/91 (H1N1) and PR8 strains, while there are 20,5, 11, 7 and 6 differences in nucleotide sequences of RNA segments 1, 2, 3, 5 and 8 between these two strains, respectively. These differences induce 10, 2, 1, 0 and 4 differences in amino acid sequences on PB2, PB1, PA,NP and NS protein molecules between A/Guangdong/6/91 (H1N1) and PR8 strains, respectively.
  
  
  CONCLUSIONS
  The possibility of laboratory contamination of A/Guangdong/6/91 (H1N1) virus can be ruled out completely. A/Guangdong/6/91 (H1N1) virus is a PR8 like strain, but not a reassortant.
authors.affiliation: Institute of Virology, Chinese Academy of Preventive Medicine, Beijing 100052, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Guo
authors.forename: M
authors.initials: M
authors.lastname: Wang
authors.forename: X
authors.initials: X
authors.lastname: Chen
mesh_terms: D002681:China; D005814:Genes, Viral / Q000235:genetics*; D006801:Humans; D009980:Influenza A virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D007251:Influenza, Human / Q000821:virology*; D012367:RNA, Viral / Q000235:genetics*; D020539:Sequence Analysis, Protein; D017423:Sequence Analysis, RNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D012367:RNA, Viral