2,3,7,8-Tetrachlorodibenzo-p-dioxin-inducible aryl hydrocarbon receptor-mediated change in CYP1A1 chromatin structure occurs independently of transcription

2,3,7,8-Tetrachlorodibenzo-p-dioxin induces, in a receptor-dependent fashion, an increase in the accessibility of CYP1A1 chromatin to restriction endonucleases. The 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced change in chromatin structure occurs rapidly and does not require ongoing RNA or protein synthesis. The increased accessibility of chromatin DNA may facilitate its subsequent interaction with other transcription factors.

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2,3,7,8-Tetrachlorodibenzo-p-dioxin-inducible aryl hydrocarbon receptor-mediated change in CYP1A1 chromatin structure occurs independently of transcription.

Molecular and Cellular Biology ◽

10.1128/mcb.9.12.5733 ◽

1989 ◽

Vol 9 (12) ◽

pp. 5733-5737 ◽

Cited By ~ 18

Author(s):

L K Durrin ◽

J P Whitlock

Keyword(s):

Protein Synthesis ◽

Transcription Factors ◽

Aryl Hydrocarbon Receptor ◽

Chromatin Structure ◽

Restriction Endonucleases ◽

Aryl Hydrocarbon ◽

Tetrachlorodibenzo P Dioxin

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Functional analysis of aryl hydrocarbon receptor (AHR) polymorphisms in pituitary adenomas (PAs) in the presence of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)

Endocrine Abstracts ◽

10.1530/endoabs.56.p777 ◽

2018 ◽

Author(s):

Jessica Debattista ◽

Robert Formosa ◽

Josanne Vassallo

Keyword(s):

Functional Analysis ◽

Aryl Hydrocarbon Receptor ◽

Pituitary Adenomas ◽

Aryl Hydrocarbon ◽

Tetrachlorodibenzo P Dioxin

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Transformation of the aryl hydrocarbon receptor to a DNA-binding form is accompanied by release of the 90 kDa heat-shock protein and increased affinity for 2,3,7,8-tetrachlorodibenzo-p-dioxin

Biochemical Journal ◽

10.1042/bj2940095 ◽

1993 ◽

Vol 294 (1) ◽

pp. 95-101 ◽

Cited By ~ 37

Author(s):

E C Henry ◽

T A Gasiewicz

Keyword(s):

Heat Shock ◽

Dna Binding ◽

Heat Shock Protein ◽

Aryl Hydrocarbon Receptor ◽

Incubation Temperature ◽

Binding Affinities ◽

Aryl Hydrocarbon ◽

Molecular Events ◽

Binding Forms ◽

Tetrachlorodibenzo P Dioxin

The binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to the aryl hydrocarbon receptor (AhR) elicits a sequence of poorly defined molecular events that ultimately yield a heteromeric transformed AhR that is active as a transcription factor. We have previously developed a model of the ligand-initiated transformation of the AhR to the DNA-binding state based on characterization of several forms of the AhR with respect to their physicochemical properties and DNA-binding affinities. The present studies were designed to determine whether, and at what stage, this process of transformation alters the receptor's affinity for TCDD. In rat hepatic cytosol, approx. 10% of the TCDD specifically bound to the AhR rapidly dissociated (t1/2 approximately 1 h), while the remainder was only slowly dissociable (t1/2 approximately 70 h). The isolated DNA-binding forms of the receptor (monomeric and transformed) bound TCDD very tightly (t1/2 > 100 h), whereas TCDD was dissociable from the non-DNA-binding receptor form(s). A lower incubation temperature (0-4 degrees C) and the presence of molybdate partially stabilized the non-DNA-binding fraction of the TCDD.receptor complex and also enhanced TCDD dissociation in crude cytosol. Immunoprecipitation of the different AhR forms with an anti-AhR antibody and immunoblotting with antibody to the 90 kDa heat-shock protein (hsp90) demonstrated that hsp90 was associated with the unoccupied receptor complex as well as with a fraction of the non-DNA-binding TCDD.receptor complex; isolated DNA-binding forms did not contain detectable hsp90. We conclude that while hsp90 remains associated with the AhR, TCDD is readily dissociable; following release of hsp90, however, TCDD becomes very tightly bound, and remains so upon completion of transformation.

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