title: [Regulation of the hepatitis B virus X promoter activity by a novel negative regulatory element].
abstract: OBJECTIVE
  To learn the effect of hepatitis B virus (HBV) sequence nt250-453 on the HBV X promoter.
  
  
  METHODS
  A plasmid pNRE-XP which contains the NRE and the HBV X promoter was constructed to co-transfect HepG2 cell line with plasmid RL-TK. The firefly luciferase activity and mRNA expression of the firefly luciferase gene were both detected. Then, nt250-453 of HBV was removed from LJ196, which contained HBV full genes. The mutated plasmid LJ196 and plasmid LJ96 which provided core protein and the viral DNA polymerase were used to co-transfect HepG2 cell line. Reverse transcription polymerase chain reaction (RT-PCR) was performed to detect the X gene mRNA level.
  
  
  RESULTS
  The activity of firefly luciferase and the expression of firefly luciferase gene mRNA were both down-regulated in the presence of the NRE, while the HBV X gene mRNA expression increased as it was removed from the HBV genes.
  
  
  CONCLUSIONS
  This study demonstrates that nt250-453 of HBV acts as a novel negative regulatory element which could suppress the HBV X promoter activity.
authors.affiliation: Institute for Viral Hepatitis, Key Laboratory of Molecular Biology of Infectious Diseases of the Ministry of Education, Chongqing University of Medical Sciences, Chongqing, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Ying
authors.initials: Y
authors.lastname: Wu
authors.forename: Wen-Lu
authors.initials: WL
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Yu
authors.forename: Ai-Long
authors.initials: AL
authors.lastname: Huang
mesh_terms: D004742:Enhancer Elements, Genetic; D015870:Gene Expression; D015967:Gene Expression Regulation, Viral; D006515:Hepatitis B virus / Q000235:genetics*; D011401:Promoter Regions, Genetic; D015534:Trans-Activators / Q000235:genetics*; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein