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Glucocorticoid receptor binds cooperatively to adjacent recognition sites
W Schmid1, U Strähle, G Schütz
1Institute of Cell and Tumor Biology, German Cancer Research Center, Heidelberg, FRG.
The EMBO Journal
|August 1, 1989
Summary
Multiple glucocorticoid response elements (GREs) significantly enhance the binding affinity and stability of the glucocorticoid receptor. This synergistic effect involves structural alterations in DNA, optimizing receptor complex formation for gene regulation.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Glucocorticoid response elements (GREs) are crucial DNA sequences that regulate gene expression upon binding of the glucocorticoid receptor.
- Understanding the mechanism of synergistic induction by multiple GREs is essential for deciphering complex gene regulation pathways.
Purpose of the Study:
- To elucidate the mechanism by which multiple GREs mediate synergistic induction.
- To analyze the binding affinity and stability of the glucocorticoid receptor to single and duplicated GREs.
Main Methods:
- Gel retardation assays
- Nitrocellulose filter binding assays
- DNase I footprinting experiments
- Direct affinity measurements and competition assays
Main Results:
- The glucocorticoid receptor exhibits a greater than 10-fold higher affinity for duplicated GREs compared to single GREs.
- Maximal complex stability is achieved with two closely spaced GREs on the same side of the DNA helix.
- Altered DNA helical patterns in intervening DNA suggest structural modifications induced by receptor binding to adjacent GREs.
Conclusions:
- Duplicated GREs significantly enhance glucocorticoid receptor binding affinity and complex stability, mediating synergistic induction.
- The spatial arrangement and proximity of GREs are critical for optimizing receptor binding and downstream effects.
- Receptor binding to adjacent GREs induces structural alterations in DNA, contributing to the observed synergistic effects.