Oligodeoxynucleotide base recognition by steroid hormone receptors

Area of Science:

• Molecular Biology
• Endocrinology
• Genetics

Background:

• Steroid holoreceptors possess DNA-binding domains crucial for their function.
• Previous studies established a binding hierarchy for oligodeoxynucleotides with the estrogen receptor (E2R).

Purpose of the Study:

• To investigate the DNA-binding domain of mouse uterine estrogen receptor (E2R) using oligodeoxynucleotides as probes.
• To characterize the differential binding of various oligodeoxynucleotides and the influence of inhibitors and accessory proteins.

Main Methods:

• Utilized oligodeoxynucleotides covalently linked to cellulose as ligands for E2R.
• Examined salt sensitivity and the effect of chaotropic salts and amino acid modifiers on binding.
• Investigated the impact of histones (H2A, H2B) and limited proteolysis on receptor binding and stabilization.

Main Results:

• Identified two types of subsites within the E2R DNA-binding domain: stable G sites and labile N sites.
• Demonstrated differential binding affinities for various oligodeoxynucleotides (oligo(dG), oligo(dT), oligo(dC), oligo(dA)).
• Showed that histones H2A and H2B stimulate binding to N sites and stabilize the holoreceptor.

Conclusions:

• Steroid holoreceptors exhibit specificity for deoxynucleotide base structures.
• Accessory proteins like histones can modulate DNA-binding interactions of steroid receptors.
• The DNA-binding domain of E2R contains distinct subsites with differential ligand recognition properties.