Conserved transactivating and pro-apoptotic functions of hepadnaviral X protein in ortho- and avihepadnaviruses.

Two established activities of the multifunctional human hepatitis B virus X-protein are its transactivating and pro-apoptotic potential. We analysed whether X-proteins from other orthohepadnaviruses and the newly discovered avihepadnaviral X-proteins have similar functions as HBx. Previously, we hav...

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Bibliographic Details
Published in:Oncogene
Main Authors: R. Schuster, E. Hildt, S. Chang, O. Terradillos, R. Lanford, W. H. Gerlich, H. Will, S. Schaefer, POLLICINO, Teresa
Other Authors: R., Schuster, E., Hildt, S., Chang, O., Terradillo, Pollicino, Teresa, R., Lanford, W. H., Gerlich, H., Will, S., Schaefer
Format: Article in Journal/Newspaper
Language:English
Published: 2002
Subjects:
HBx
transcriptional transactivation
Apoptosi
HCC
Avihepadnavirus
DHBV
PROGRAMMED CELL-DEATH
HEPATITIS-B VIRUS
Arctic
Online Access:http://hdl.handle.net/11570/1896240
https://doi.org/10.1038/sj.onc.1205916
Description
Summary:Two established activities of the multifunctional human hepatitis B virus X-protein are its transactivating and pro-apoptotic potential. We analysed whether X-proteins from other orthohepadnaviruses and the newly discovered avihepadnaviral X-proteins have similar functions as HBx. Previously, we have shown that HBx suppresses oncogenic transformation of primary rat embryo fibroblasts (REF) by induction of apoptosis. Using this system, we found that the wildtype X-proteins of woodchuck, ground squirrel, arctic squirrel and woolly monkey hepatitis B virus exhibit similar levels of pro-apoptotic activity as HBx, whereas mutants with carboxyterminal deletions were severely impaired in this activity. A strong correlation between the pro-apoptotic and transactivating abilities of the mammalian X-proteins was found. The newly discovered avihepadnaviral X-like proteins showed similar and Raf-MAPK pathway-dependent transactivating abilities and induced apoptosis in the REF-assay. Our data indicate that the transactivating and pro-apoptotic activities reside in the carboxyterminal half of orthohepadnaviral X and are conserved in avihepadnaviral X-proteins.

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