title: [Effect of hepatitis B virus X protein on suppressor of cytokine signaling-1 expression].
abstract: OBJECTIVE
  To investigate the effect of hepatitis B virus-encoded X protein (HBx) on the expression of host-encoded suppressor of cytokine signaling-1 (SOCS-1) and to explore the possibility of an underlying mechanism involving modulation of CpG island methylation in the SOCS-1 gene promoter.
  
  
  METHODS
  The immortalized human derived non-tumor liver cell line QSG7701 was transfected with a recombinant HBx plasmid (pcDNA-X) or an empty vector control plasmid (pcDNA3.0) and stably transfected clones were selected by G418 resistance screening. Untransfected cells served as negative controls. Expression of SOCS-1 mRNA and protein was detected by real-time quantitative PCR and western blotting. The methylation status of SOCS-1 was detected by methylation-specific PCR (MSP). The significance of intergroup differences was analyzed by one-way ANOVA or pairwise comparison with post-hoc LSD test.
  
  
  RESULTS
  SOCS-1 mRNA level was significantly lower in the pcDNA-X/QSG7701 cells compared to that in the pcDNA3.0/QSG7701 and untransfected cells (0.3249+/-0.0536 vs. 1.0543+/-0.1937 and 1.00; F = 19.6, P = 0.042). SOCS-1 protein level was similarly lower in the pcDNA-X/QSG7701 cells (0.1496+/-0.0106 vs. 0.1984+/-0.0438 and 0.2152+/-0.0816; F = 19.4, P = 0.048). The SOCS-1 promoter region showed methylation only in the pcDNA-X/QSG7701 cells.
  
  
  CONCLUSIONS
  HBx-expressing human hepatocytes have down-regulated SOCS-1 expression, both at the mRNA and protein levels, and this effect corresponds to increased methylation in the SOCS-1 promoter region harboring CpG islands.
authors: Department of Infectious Diseases, Xiangya Hospital of Central South University, Viral Hepatitis Key Laboratary of Hunan Province, Changsha 410008, China.
authors: Xiao-ling
authors: XL
authors: Song
authors: Guo-zhen
authors: GZ
authors: Liu
authors: De-ming
authors: DM
authors: Tan
authors: Yan-yan
authors: YY
authors: Li
mesh_terms: D002460:Cell Line; D018899:CpG Islands; D019175:DNA Methylation; D006801:Humans; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D012333:RNA, Messenger; C108944:SOCS1 protein, human; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein