| Summary: | 碩士 === 國立臺灣大學 === 生化學研究所 === 84 === HDV-encoded proteins, HDAg-S and HDAg-L of delta antigen, are nuclear
phosphoproteins. The HDAg-S appears to be required for the replication
of HDV replication and is required for the assembly of HDV. Cellular
factors may be involved in controlling the process of HDV replication.
In this study, whether the retinoblastoma protein (RB) and p53 can
interact with HDAg-S and affect HDV replication is examined.
Coimmunoprecipitation study with rabbit polyclonoal antibodies
specifically against the C terminus of the human RB demonstrate an
interaction between the HDAg-S and RB. However, the HDAg-S could not be
coimmunoprecipitation with p53 in the presence of a monoclonal antibody
against p53. By transfecting a dimeric HDV cDNA together with a plasmid
encoding RB and p53 into Saos-2 cells, RB was demonstrated to transactivate
the replication of HDV, whereas p53 appears to inhibit the replication
of HDV. It is the effect of p53 on the replicaiton of HDV because Saos-2
cells transfected with p53 may induce apoptosis when the normal function
of RB is lacking. It has been demostrated that Saos-2 cells transfected
with RB were arrested in the late G1 phase. This may provide abundant
free transcriptional machinery of the transfected Saos-2 cells to support
the replication of HDV. In addition, the formation of RB-HDAg-S complexes
may induce cytopathic effects in HDV-infected cells.
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