Differential modulation of androgen receptor action by deoxyribonucleic acid response elements

Area of Science:

• Molecular Biology
• Genetics
• Endocrinology

Background:

• Steroid receptors bind to specific DNA sequences called response elements.
• Androgen receptor (AR) recognizes both steroid response elements (SREs) and a distinct class, androgen response elements (AREs).
• The differential roles of SREs and AREs in modulating AR function remain incompletely understood.

Purpose of the Study:

• To investigate the differential roles of SREs and AREs in modulating androgen receptor (AR) function.
• To elucidate how DNA response element class influences AR activity, coactivator recruitment, and responses to post-translational modifications like sumoylation.

Main Methods:

• Purification of AR complexes bound to SREs and AREs.
• Limited protease digestion to assess differential accessibility of bound AR.
• Transactivation assays using AR mutants and specific response elements.
• Analysis of AR activity modulation by coactivators (TIF2, ARA55) and sumoylation enzymes (Ubc9, PIASxα).

Main Results:

• AR complexes bound to SREs and AREs exhibited differential accessibility to protease digestion.
• AR mutants showed varied effects on transactivation depending on the response element (SRE vs. ARE).
• Coactivator and sumoylation enzyme effects on AR activity differed significantly between SREs and AREs, with notable distinctions for Pem ARE-2.

Conclusions:

• DNA response elements (SREs and AREs) play a crucial role in modulating androgen receptor (AR) activity.
• The specific DNA response element bound by AR is determinative for the specificity of gene expression.
• Differential interactions with coactivators and sumoylation machinery contribute to element-specific AR function.