| Abstrakt: |
Oncofetal antigens such as alpha-fetoprotein (AFP) are expressed in regenerating liver. The level of AFP geneexpression during liver regeneration is regulated by the unlinked, autosomal gene,lpha-etoprotein regulator2 (Afr2). C3H/HeJ (Afr2A/A) mice express 10-fold higher levels of AFP than C57BL/6J (Afr2B/B) mice.Here we show that primary hepatocytes isolated from C3H/HeJ and C57BL/6J mice exhibit differential expressionof the endogenous AFP gene, which was attributed to the Afr2 gene locus and indicative of a cellautonomousmechanism. We show that thefr2-esponselement (ARE), between 1010 and 838 base pairsupstream of the AFP transcriptional start site, did not modulate reporter gene expression in transfection assaysof Hep G2, Hep 3B, Hepa 1.6, and HeLa cell lines. Reporter gene expression in transiently transfectedprimary hepatocytes was also ARE-independent. Finally, gene expression from reporter constructs deliveredby hydrodynamics-based transfection to the livers of C3H/HeJ and C57BL/6J mice after CCl-induced liverregeneration was ARE-independent. In conclusion, ARE-dependent transcription was not found in transientassays performed in three different systems, two of which retained regulation of the endogenous AFP gene,suggesting that the ARE may not function as a simple transcription factor recognition site. [ABSTRACT FROM AUTHOR] |
