Activation of the glutathione peroxidase 2 (GPx2) promoter by β-catenin
-
Anna Kipp
Abstract
GPx2, formerly named gastrointestinal glutathione peroxidase, is highly expressed in the proliferative area of the intestinal crypt-to-villus axis and in Paneth cells. Additionally, GPx2 is transiently up-regulated during development of gastrointestinal adenocarcinomas. Because both normal proliferation and differentiation of intestinal epithelial cells as well as carcinogenesis are regulated by the Wnt pathway, it was tested whether GPx2 may be a target of the β-catenin/TCF complex which transfers Wnt signals. The GPx2 promoter contains five putative β-catenin/TCF binding sites. Accordingly, the promoter was active in two cell lines with a constitutively active Wnt pathway, HepG2 and SW480, but not in BHK-21 cells in which the pathway is silent. Overexpression of β-catenin/TCF activated the GPx2 promoter in all three cell lines. Overexpression of wild-type adenomatous polyposis coli (APC) in SW480 cells which harbor a mutated APC gene decreased basal GPx2 promoter activity. Truncation of the promoter identified one β-catenin/TCF binding site that was sufficient for activation. Mutation of this site reduced the response to β-catenin/TCF by more than 50%. These findings suggest a function of GPx2 in the maintenance of normal renewal of the intestinal epithelium. Whether up-regulation of GPx2 during carcinogenesis supports tumor growth or can rather be considered as a counteracting effect remains to be investigated.
©2007 by Walter de Gruyter Berlin New York
Articles in the same Issue
- Selenoproteins – biochemistry and clinical relevance
- Selenium in mammalian spermiogenesis
- Selenium in chemistry and biochemistry in comparison to sulfur
- Molecular biology of glutathione peroxidase 4: from genomic structure to developmental expression and neural function
- Physiological role of phospholipid hydroperoxide glutathione peroxidase in mammals
- Activation of the glutathione peroxidase 2 (GPx2) promoter by β-catenin
- Effect of age on sexually dimorphic selenoprotein expression in mice
- Post-translational processing of selenoprotein P: implications of glycosylation for its utilisation by target cells
- Selenoproteins of the thyroid gland: expression, localization and possible function of glutathione peroxidase 3
- Towards understanding selenocysteine incorporation into bacterial proteins
- Glutathione- and thioredoxin-related enzymes are modulated by sulfur-containing chemopreventive agents
- B- and T-cell-specific inactivation of thioredoxin reductase 2 does not impair lymphocyte development and maintenance
- Effect of selenium on thioredoxin reductase activity in Txnrd1 or Txnrd2 hemizygous mice
- Influence of pH and flanking serine on the redox potential of S-S and S-Se bridges of Cys-Cys and Cys-Sec peptides
- An essential role for Pin1 in Xenopus laevis embryonic development revealed by specific inhibitors
- Glucocorticoid receptor-mediated expression of kallikrein 10 in human breast cancer cell lines
Articles in the same Issue
- Selenoproteins – biochemistry and clinical relevance
- Selenium in mammalian spermiogenesis
- Selenium in chemistry and biochemistry in comparison to sulfur
- Molecular biology of glutathione peroxidase 4: from genomic structure to developmental expression and neural function
- Physiological role of phospholipid hydroperoxide glutathione peroxidase in mammals
- Activation of the glutathione peroxidase 2 (GPx2) promoter by β-catenin
- Effect of age on sexually dimorphic selenoprotein expression in mice
- Post-translational processing of selenoprotein P: implications of glycosylation for its utilisation by target cells
- Selenoproteins of the thyroid gland: expression, localization and possible function of glutathione peroxidase 3
- Towards understanding selenocysteine incorporation into bacterial proteins
- Glutathione- and thioredoxin-related enzymes are modulated by sulfur-containing chemopreventive agents
- B- and T-cell-specific inactivation of thioredoxin reductase 2 does not impair lymphocyte development and maintenance
- Effect of selenium on thioredoxin reductase activity in Txnrd1 or Txnrd2 hemizygous mice
- Influence of pH and flanking serine on the redox potential of S-S and S-Se bridges of Cys-Cys and Cys-Sec peptides
- An essential role for Pin1 in Xenopus laevis embryonic development revealed by specific inhibitors
- Glucocorticoid receptor-mediated expression of kallikrein 10 in human breast cancer cell lines
