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The constitution of a progesterone response element
B A Lieberman1, B J Bona, D P Edwards
1Department of Pathology, University of Colorado Health Sciences Center, Denver 80262.
Molecular Endocrinology (Baltimore, Md.)
|April 1, 1993
Summary
Researchers identified the optimal DNA sequence for progesterone receptor (PR) binding, revealing key determinants for gene regulation. This finding advances understanding of hormone receptor-DNA interactions and their impact on gene expression.
Area of Science:
- Molecular Biology
- Genetics
- Endocrinology
Background:
- Progesterone receptors (PRs) regulate gene expression through sequence-specific DNA binding.
- Understanding these recognition sequences is crucial for deciphering hormonal control of cellular processes.
Purpose of the Study:
- To define the precise DNA sequence determinants governing progesterone receptor (PR) binding.
- To correlate in vitro PR-DNA binding with in vivo gene activation mediated by PR.
Main Methods:
- Analysis of point substitution and insertion mutants of the mouse mammary tumor virus (MMTV) progesterone response element (PRE).
- In vitro assessment of PR-DNA binding affinity.
- In vivo reporter gene assays to measure PR-mediated transcriptional activation.
Main Results:
- An optimal PR recognition sequence, -7RGNACANRNTGTNCY+7, was inferred, featuring hexameric half-sites separated by 3 bp with dyad symmetry.
- Specific base substitutions, particularly a G for T at the first position, enhanced PR binding.
- Insertion of a base pair between half-sites abolished binding, indicating fixed spatial orientation of receptor subunits.
Conclusions:
- PR binding is highly sequence-specific, with defined optimal and permissible variations.
- In vitro binding affinity generally correlates with in vivo transcriptional activity, though some exceptions exist.
- PR and glucocorticoid receptors share similar DNA recognition patterns, suggesting potential cross-reactivity.