ABSTRACT
The hepatitis delta virus consists of a circular RNA genome that encodes a single protein, the delta antigen. The virus replicates in an unusual fashion that is similar to the process used by plant viroids. The viral RNA is duplicated in a ‘rolling circle’ mechanism in which antigenomic RNA is produced in a long chain; the long chain of multiple, joined viral genomes is then cleaved by a ribozyme. Ribozymes are enzymes that are formed by loops of RNA and are able to process RNA – hence the hepatitis delta virus RNA is able to form loops that cleave the viral RNA during replication. This unusual replication is an attractive target for the development of antiviral drugs but, to date, none that targets the hepatitis delta virus ribozyme has been developed.
