Abstract
Molecular properties of cytosolic Ah receptors from livers of Sprague-Dawley rats and C57BL/6N mice were assessed by velocity sedimentation on sucrose gradients and by gel permeation chromatography on Sephacryl S-300. Analyses were done under conditions of both moderate ionic strength (presence of 0.1 M KCl) and high ionic strength (0.4 M KCl). [3H]2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was used as the radioligand. In conditions of moderate ionic strength the receptor from Sprague-Dawley rat liver sedimented at 88 ± 0.05 S, had a Stokes radius of 7.0 ± 0.21 nm, and an apparent relative molecular mass (M(r)) of 257,000 ± 7,700. In conditions of high ionic strength the Ah receptor from rat hepatic cytosol dissociated to a [3H]TCDD-binding subunit which sedimented at 5.6 ± 0.58 S, had a Stokes radius of 5.2 ± 0.24 nm, and an apparent M(r) of 121,000 ± 5,600. The Ah receptor from liver of C57BL/6N mice, in moderate ionic strength conditions, sedimented at 9.4 ± 0.54 S, had a Stokes radius of 7.1 ± 0.12 nm, and an apparent M(r) of 277,000 ± 4,800. Whereas the Ah receptor from rat liver readily dissociated into a [3H]TCDD-binding subunit during brief exposure to 0.4 M KCl, the mouse Ah receptor resisted dissociation. When exposed to 0.4 M KCl for 2 h, the mouse Ah receptor remained at the same molecular size that it had exhibited in moderate ionic strength conditions. Prolonged exposure (16 h) to 0.4 M KCl prior to analysis partially converted the mouse Ah receptor into a smaller [3H]TCDD-binding subunit which sedimented at 4.9 ± 0.07 S, had a Stokes radius of 5.2 ± 0.19 nm, and an apparent M(r) of 105,000 ± 3,800. The potency of seven different Ah receptor agonists in competing with [3H]TCDD for specific receptor sites was slightly different in mouse cytosol than in rat cytosol. By criteria of size, response to high ionic strength environments, and ligand binding preferences the mouse and rat Ah receptors appear to be similar but not identical molecular species.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3987-3995 |
| Number of pages | 9 |
| Journal | Journal of Biological Chemistry |
| Volume | 261 |
| Issue number | 9 |
| State | Published - 1986 |
| Externally published | Yes |
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- Biochemistry
Cite this
Structure and function of the Ah receptor for 2,3,7,8-tetrachlorodibenzo-p-dioxin. Species difference in molecular properties of the receptors from mouse and rat hepatic cytosols. / Denison, M. S.; Vella, L. M.; Okey, A. B.
In: Journal of Biological Chemistry, Vol. 261, No. 9, 1986, p. 3987-3995.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Structure and function of the Ah receptor for 2,3,7,8-tetrachlorodibenzo-p-dioxin. Species difference in molecular properties of the receptors from mouse and rat hepatic cytosols
AU - Denison, M. S.
AU - Vella, L. M.
AU - Okey, A. B.
PY - 1986
Y1 - 1986
N2 - Molecular properties of cytosolic Ah receptors from livers of Sprague-Dawley rats and C57BL/6N mice were assessed by velocity sedimentation on sucrose gradients and by gel permeation chromatography on Sephacryl S-300. Analyses were done under conditions of both moderate ionic strength (presence of 0.1 M KCl) and high ionic strength (0.4 M KCl). [3H]2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was used as the radioligand. In conditions of moderate ionic strength the receptor from Sprague-Dawley rat liver sedimented at 88 ± 0.05 S, had a Stokes radius of 7.0 ± 0.21 nm, and an apparent relative molecular mass (M(r)) of 257,000 ± 7,700. In conditions of high ionic strength the Ah receptor from rat hepatic cytosol dissociated to a [3H]TCDD-binding subunit which sedimented at 5.6 ± 0.58 S, had a Stokes radius of 5.2 ± 0.24 nm, and an apparent M(r) of 121,000 ± 5,600. The Ah receptor from liver of C57BL/6N mice, in moderate ionic strength conditions, sedimented at 9.4 ± 0.54 S, had a Stokes radius of 7.1 ± 0.12 nm, and an apparent M(r) of 277,000 ± 4,800. Whereas the Ah receptor from rat liver readily dissociated into a [3H]TCDD-binding subunit during brief exposure to 0.4 M KCl, the mouse Ah receptor resisted dissociation. When exposed to 0.4 M KCl for 2 h, the mouse Ah receptor remained at the same molecular size that it had exhibited in moderate ionic strength conditions. Prolonged exposure (16 h) to 0.4 M KCl prior to analysis partially converted the mouse Ah receptor into a smaller [3H]TCDD-binding subunit which sedimented at 4.9 ± 0.07 S, had a Stokes radius of 5.2 ± 0.19 nm, and an apparent M(r) of 105,000 ± 3,800. The potency of seven different Ah receptor agonists in competing with [3H]TCDD for specific receptor sites was slightly different in mouse cytosol than in rat cytosol. By criteria of size, response to high ionic strength environments, and ligand binding preferences the mouse and rat Ah receptors appear to be similar but not identical molecular species.
AB - Molecular properties of cytosolic Ah receptors from livers of Sprague-Dawley rats and C57BL/6N mice were assessed by velocity sedimentation on sucrose gradients and by gel permeation chromatography on Sephacryl S-300. Analyses were done under conditions of both moderate ionic strength (presence of 0.1 M KCl) and high ionic strength (0.4 M KCl). [3H]2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was used as the radioligand. In conditions of moderate ionic strength the receptor from Sprague-Dawley rat liver sedimented at 88 ± 0.05 S, had a Stokes radius of 7.0 ± 0.21 nm, and an apparent relative molecular mass (M(r)) of 257,000 ± 7,700. In conditions of high ionic strength the Ah receptor from rat hepatic cytosol dissociated to a [3H]TCDD-binding subunit which sedimented at 5.6 ± 0.58 S, had a Stokes radius of 5.2 ± 0.24 nm, and an apparent M(r) of 121,000 ± 5,600. The Ah receptor from liver of C57BL/6N mice, in moderate ionic strength conditions, sedimented at 9.4 ± 0.54 S, had a Stokes radius of 7.1 ± 0.12 nm, and an apparent M(r) of 277,000 ± 4,800. Whereas the Ah receptor from rat liver readily dissociated into a [3H]TCDD-binding subunit during brief exposure to 0.4 M KCl, the mouse Ah receptor resisted dissociation. When exposed to 0.4 M KCl for 2 h, the mouse Ah receptor remained at the same molecular size that it had exhibited in moderate ionic strength conditions. Prolonged exposure (16 h) to 0.4 M KCl prior to analysis partially converted the mouse Ah receptor into a smaller [3H]TCDD-binding subunit which sedimented at 4.9 ± 0.07 S, had a Stokes radius of 5.2 ± 0.19 nm, and an apparent M(r) of 105,000 ± 3,800. The potency of seven different Ah receptor agonists in competing with [3H]TCDD for specific receptor sites was slightly different in mouse cytosol than in rat cytosol. By criteria of size, response to high ionic strength environments, and ligand binding preferences the mouse and rat Ah receptors appear to be similar but not identical molecular species.
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M3 - Article
VL - 261
SP - 3987
EP - 3995
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 9
ER -