2,3,7,8-Tetrachlorodibenzo-p-dioxin receptors in wild type and variant mouse hepatoma cells. Nuclear location and strength of nuclear binding |
| |
Authors: | J P Whitlock D R Galeazzi |
| |
Abstract: | The volume of aqueous solvent present during subcellular fractionation of mouse hepatoma (Hepa 1c1c7) cells influences the distribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) receptors between the nuclear and cytosolic fractions. When the effects of dilution are minimized, at least 80% of the receptors associate with nuclei. The receptors bind relatively strongly to nuclei, as measured by their release by KCl. TCDD-receptor complexes bind more strongly to nuclei than do unoccupied receptors. A temperature-dependent event further enhances the binding of TCDD-receptor complexes to nuclei. A class of variant cells contains receptors which bind relatively weakly to nuclei; this defect accounts for the variant phenotype. We conclude that, in the intact cell, TCDD receptors are located within the nucleus and that the temperature-dependent event in the induction of cytochrome P1-450 gene expression is one which strengthens the binding of the TCDD-receptor complex to chromatin. |
| |
Keywords: | |
|
|