Related Experiment Video
Updated: Aug 17, 2026

Development of a Hepatitis B Virus Reporter System to Monitor the Early Stages of the Replication Cycle
Published on: February 1, 2017
Negative regulation of the hepatitis B virus pre-S1 promoter by internal DNA sequences
1Department of Microbiology and Immunology, University of Colorado School of Medicine, Denver 80262.
Abstract:
Expression of the surface antigen gene (S gene) of hepatitis B virus is directed by two distinct promoter elements with markedly different activities. The upstream (pre-S1) promoter produces a 2.4-kb transcript at very low levels while the downstream (pre-S2) promoter produces an approximately 2.1-kb transcript in relative abundance. We have constructed a series of internal deletion mutants to analyze differential regulation of the two S gene promoters. We show here that expression directed by the pre-S1 promoter is negatively regulated by DNA sequences containing the downstream pre-S2 promoter region. Nuclear run-on analysis indicates this down-regulation to be at the level of transcription. Furthermore, promoter repression does not appear to be due to products of the S gene region. Deletion mutagenesis studies have permitted the localization of a 61-bp region that may be involved in the apparent down-regulation of the pre-S1 promoter. These results suggest the use of an unusual regulatory mechanism by a dipromoter gene in which an active internal promoter may preclude efficient use of an upstream promoter.
Related Concept Videos
The Eukaryotic Promoter Region
Eukaryotic Transcription Inhibitors
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Leaky Scanning
Viruses with RNA Genomes
Hepatitis
Inhibitors Of Virion Release

