The S promoter of hepatitis B virus is regulated by positive and negative elements.
AUTOR(ES)
De-Medina, T
RESUMO
The S promoter, one of the major hepatitis B virus (HBV) promoters, directs the synthesis of mRNA for surface antigen. Transient expression studies revealed that this promoter is highly active in the Alexander hepatoma cell line but not in SK-Hep1 and HeLa cells. We found that a distal element of the promoter (-103 to -48) confers this cell-type-specific behavior through a mechanism in which the promoter activity is repressed in HeLa and SK-Hep1 cells but increased in Alexander cells. By using an inhibitor of protein synthesis, we obtained evidence that a labile repressor(s) confers the negative effect in SK-Hep1 cells. We also found an enhancerlike activity associated with a small DNA segment of the S promoter (-27 to + 30). This proximal element was active in HeLa and SK-Hep1 cells only in the absence of the distal negative element. Finally, analysis of S promoter deletion mutants demonstrated that the -27 to -17 region of the S promoter is crucial for its activity.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=363444Documentos Relacionados
- Lysozyme gene activity in chicken macrophages is controlled by positive and negative regulatory elements.
- A developmentally regulated Caulobacter flagellar promoter is activated by 3' enhancer and IHF binding elements.
- Simian virus 40 T antigen activates the late promoter by modulating the activity of negative regulatory elements.
- Hepatocyte-specific expression of the hepatitis B virus core promoter depends on both positive and negative regulation.
- Pancreatic beta-cell-type-specific expression of the rat insulin II gene is controlled by positive and negative cellular transcriptional elements.