title: [Quasispecies and variations of hepatitis B virus: core promotor region as an example].
abstract: OBJECTIVE
  To investigate the HBV quasispecies groups in the patients with chronic HBV infection.
  
  
  METHODS
  A set of specific primers was synthesized according to DNA sequence of HBV strain found in China. The whole core promoter (CP) region was amplified by PCR method from the sera of 3 patients with chronic HBV infection, and the PCR products were subcloned into pGEM Teasy vectors. The clones were randomly selected to be sequenced. Sequence comparison of the selected clones was made to find the difference.
  
  
  RESULTS
  By comparison, it was found that each sequence of selected clones was different. The point mutation always occurred in TATA-like boxes, especially from T to C replacement on 184 site. There is a hot region (33.3% 5/15) in basic core promoter where deletion mutation frequently happened.
  
  
  CONCLUSIONS
  There is a hot deletion region near DR I in CP. The replacement at 184 nt (T to C) in the third TATA-like box may influence the expression of pre-C/C protein. The sequencing results suggest that there are HBV quasispecies groups in chronically infected patients.
authors.affiliation: Gene Therapy Research Center, Institute of Infectious Diseases, The 302nd Hospital of PLA, Beijing 100039, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Dong
authors.forename: Jun
authors.initials: J
authors.lastname: Cheng
authors.forename: Qinhuan
authors.initials: Q
authors.lastname: Wang
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Shi
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Xia
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Guoqing
authors.initials: G
authors.lastname: Zhang
authors.forename: Chongwen
authors.initials: C
authors.lastname: Si
mesh_terms: D004279:DNA, Viral / Q000032:analysis; D005814:Genes, Viral / Q000235:genetics*; D014644:Genetic Variation; D006512:Hepatitis B Core Antigens / Q000235:genetics*; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000821:virology*; D006801:Humans; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D016385:TATA Box / Q000235:genetics
chemical_list: D004279:DNA, Viral; D006512:Hepatitis B Core Antigens