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The core promoter of hepatitis B virus
Author(s) -
Kramvis A.,
Kew M. C.
Publication year - 1999
Publication title -
journal of viral hepatitis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.329
H-Index - 100
eISSN - 1365-2893
pISSN - 1352-0504
DOI - 10.1046/j.1365-2893.1999.00189.x
Subject(s) - transcription (linguistics) , biology , hepatitis b virus , hbeag , transversion , messenger rna , promoter , virology , open reading frame , regulatory sequence , hepatitis b virus pre beta , rna , microbiology and biotechnology , genetics , transcription factor , gene , virus , mutation , gene expression , hepatitis b virus dna polymerase , hbsag , peptide sequence , philosophy , linguistics
The core promoter (CP) of hepatitis B virus (HBV) plays a central role in HBV replication and morphogenesis, directing the transcription of both species of 3.5 kb mRNA: pregenomic (pg) RNA and precore (pre‐C) mRNA. The CP overlaps the 3′ end of the X open‐reading frame (ORF) and the 5′ end of the pre‐C/C ORF. The major functional elements of the CP are the upper regulatory region (URR) and the basic core promoter (BCP). The BCP is sufficient for accurate initiation of both pre‐C mRNA and pgRNA transcription. It contains four AT‐rich regions and the initiators for pre‐C mRNA and pgRNA transcription. The upstream regulatory region consists of the negative regulatory element and the core upstream regulatory sequence. Co‐operative interaction of various liver‐enriched and ubiquitous transcription factors is necessary for liver‐specific expression from the CP. These factors bind to the CP. Sequence conservation within the CP is crucial for maintaining active viral replication, and variation may contribute to the persistence of HBV within the host, leading to chronic infection and, ultimately, hepatocarcinogenesis. The most frequently described mutations within this region are an A to T transversion at position 1762 together with a G to A transition at position 1764. This double mutant is accompanied by a reduced level of hepatitis B e antigen (HBeAg) expression. Deletions, insertions and duplications occur within the CP.