Prospects for inhibiting the post-transcriptional regulation of gene expression in hepatitis B virus.
There is a continuing need for novel antivirals to treat hepatitis B virus (HBV) infection, as it remains a major health problem worldwide. Ideally new classes of antivirals would target multiple steps in the viral lifecycle. In this review, we consider the steps in which HBV RNAs are processed, exported from the nucleus and translated. These are often overlooked steps in the HBV life-cycle. HBV, like retroviruses, incorporates a number of unusual steps in these processes, which use a combination of viral and host cellular machinery. Some of these unusual steps deserve a closer scrutiny. They may provide alternative targets to existing antiviral therapies, which are associated with increasing drug resistance. The RNA post-transcriptional regulatory element identified 20 years ago promotes nucleocytoplasmic export of all unspliced HBV RNAs. There is evidence that inhibition of this step is part of the antiviral action of interferon. Similarly, the structured RNA epsilon element situated at the 5' end of the polycistronic HBV pregenomic RNA also performs key roles during HBV replication. The pregenomic RNA, which is the template for translation of both the viral core and polymerase proteins, is also encapsidated and used in replication. This complex process, regulated at the epsilon element, also presents an attractive antiviral target. These RNA elements that mediate and regulate gene expression are highly conserved and could be targeted using novel strategies employing RNAi, miRNAs or aptamers. Such approaches targeting these functionally constrained genomic regions should avoid escape mutations. Therefore understanding these regulatory elements, along with providing potential targets, may also facilitate the development of other new classes of antiviral drugs.
['Chen|Augustine|A|', 'Panjaworayan T-Thienprasert|Nattanan|N|', 'Brown|Chris M|CM|']
D000818:Animals D000998:Antiviral Agents D015195:Drug Design D015967:Gene Expression Regulation, Viral D006509:Hepatitis B D006515:Hepatitis B virus D006801:Humans D012323:RNA Processing, Post-Transcriptional D012367:RNA, Viral D014764:Viral Proteins
Hepatitis B virus Antiviral Nucleocytoplasmic export Nuclear export Post-transcriptional control Translational control