title: [Quasispecies and mutation of hepatitis B virus polymerase gene in lamivudine- treated patients].
abstract: OBJECTIVE
  To study the quasispecies and mutation features of hepatitis B virus polymerase (HBV P) gene in chronic hepatitis B patients before and after lamivudine treatment.
  
  
  METHODS
  The HBV P gene was amplificated with PCR and cloned, then single strand conformation polymorphism / heteroduplex analysis (SSCP/HDA) was applied to analyze the quasispecies complexity and mutation characters of HBV P gene.
  
  
  RESULTS
  The quasispecies number of HBV P gene before treatment was larger than that after treatment (7 to 14 vs. 4 to 8, t = 3.98, P < 0.05). Six patients had one or two predominant quasispecies before therapy, but the percentages of predominant quasispecies were lower than those after therapy (33.3% to 81.8% vs. 78.8% to 90.9%, t = 3.42, P < 0.05). By sequencing the predominant clones, there were 2 patients with M550V/L528M mutation, 3 patients with M550I mutation and 1 patient with wild type after lamivudine therapy. Additionally, there were individualization mutations which had no obvious tender.
  
  
  CONCLUSIONS
  Quasispecies of hepatitis B virus are changed under the selection of lamivudine, meanwhile, the mutation at YMDD motif emerges.
authors.affiliation: Department of Infectious Diseases, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Yan-ping
authors.initials: YP
authors.lastname: Huang
authors.forename: Yu-ming
authors.initials: YM
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Lan
authors.forename: Yi
authors.initials: Y
authors.lastname: Fan
mesh_terms: D000998:Antiviral Agents / Q000627:therapeutic use; D004279:DNA, Viral / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000235:genetics; D005260:Female; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D019259:Lamivudine / Q000627:therapeutic use*; D008297:Male; D017354:Point Mutation / Q000235:genetics*
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D019259:Lamivudine; D004259:DNA-Directed DNA Polymerase