Previous Article | Next Article ![]()
J. Virol., 08 1996, 4986-4995, Vol 70, No. 8
MR Beard, TB MacNaughton and EJ Gowans
Transcription and replication of hepatitis delta virus (HDV) RNA are
performed by the cellular enzyme RNA polymerase II (Pol II). As DNA is the
normal template for Pol II, the enzyme must undergo template switching. The
mechanism for this is unknown, but since HDV RNA can form a rod-like
molecule by extensive intramolecular base pairing, it has been suggested
that a double-stranded region(s) of HDV RNA serves as a recognition site
for Pol II. A bidirectional promoter has been identified previously on HDV
cDNA (T. B. Macnaughton, M. R. Beard, M. Chao, E. J. Gowans, and M. M. C.
Lai, Virology 196:629-636, 1993). In the present study, genomic RNA
corresponding to this region was able to direct the synthesis of
antigenomic RNA in a nuclear extract transcription reaction, whereas
genomic RNA species containing a mutation that resulted in a
replication-defective phenotype were unable to do so. Thus, this region,
the location of which is defined as nucleotides 1608 to 1669 on the basis
of a highly conserved structure, represents a RNA-RNA promoter. Computer
analysis of the RNA secondary structure predicted that the promoter
contains two bulge regions in a stem-loop structure which encompasses a
GC-rich motif. This predicted model was confirmed by enzyme digestion and
primer extension analysis. The promoter is located at one end of the rod
and has some homology with the simian virus 40 late promoter. A number of
other mutations were introduced within this region, and expression plasmids
were constructed to examine the effects of mutations in the promoter on HDV
replication. Disruption of the overall secondary structure, particularly
the bulge regions, totally inhibited HDV RNA replication.
Copyright © 1996, American Society for Microbiology
Identification and characterization of a hepatitis delta virus RNA transcriptional promoter
Sir Albert Sakzewski Virus Research Centre, Royal Children's Hospital, Brisbane, Queensland, Australia.
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|