11 research outputs found
Thyroid Hormone Receptor alpha-1 Directly Controls Transcription of the beta-Catenin Gene in Intestinal Epithelial Cells
Thyroid hormones, T3 and T4, are known regulators of intestine development. The best characterized example is the remodeling of the gastrointestinal tract during amphibian metamorphosis. Thyroid hormones act via nuclear receptors, the TRs, which are T3-dependent transcription factors. We previously showed that intestinal epithelial cell proliferation is controlled by thyroid hormones and the TRalpha gene. To analyze the mechanisms responsible, we studied the expression of genes belonging to and/or activated by the Wnt/beta-catenin pathway, a major actor in the control of physiological and pathological epithelial proliferation in the intestine. We show that T3-TR1 controls the transcription of the beta-catenin gene in an epithelial cell-autonomous way. This is parallel to positive regulation of proliferation-controlling genes such as type D cyclins and c-myc, known targets of the Wnt/-beta-catenin. In addition, we show that the regulation of the beta-catenin gene is direct, as TR binds in vitro and in chromatin in vivo to a specific thyroid hormone-responsive element present in intron 1 of this gene. This is the first report concerning in vivo transcriptional control of the beta-catenin gene. As Wnt/beta-catenin plays a crucial role in intestinal tumorigenesis, our observations open a new perspective on the study of TRs as potential tumor inducers
<Abstract of published report>Novel Derivatives of 5-Fluorouridine and 5-Fluorouracil Having Potent Antitumor and Lower Immunosuppressive Activities.
<Abstract of published report>Novel lowly immunosuppressive antitumor fluorouridine derivative, UK-21 : antitumor activity and effect on humoral immune response in mice.
Thyroid Hormone Receptor α1 Directly Controls Transcription of the β-Catenin Gene in Intestinal Epithelial Cells
Thyroid hormones, T3 and T4, are known regulators of intestine development. The best characterized example is the remodeling of the gastrointestinal tract during amphibian metamorphosis. Thyroid hormones act via nuclear receptors, the TRs, which are T3-dependent transcription factors. We previously showed that intestinal epithelial cell proliferation is controlled by thyroid hormones and the TRα gene. To analyze the mechanisms responsible, we studied the expression of genes belonging to and/or activated by the Wnt/β-catenin pathway, a major actor in the control of physiological and pathological epithelial proliferation in the intestine. We show that T3-TRα1 controls the transcription of the β-catenin gene in an epithelial cell-autonomous way. This is parallel to positive regulation of proliferation-controlling genes such as type D cyclins and c-myc, known targets of the Wnt/β-catenin. In addition, we show that the regulation of the β-catenin gene is direct, as TR binds in vitro and in chromatin in vivo to a specific thyroid hormone-responsive element present in intron 1 of this gene. This is the first report concerning in vivo transcriptional control of the β-catenin gene. As Wnt/β-catenin plays a crucial role in intestinal tumorigenesis, our observations open a new perspective on the study of TRs as potential tumor inducers