Allosteric modulation of estrogen receptor conformation by different estrogen response elements

Area of Science:

• Molecular Biology
• Genetics
• Endocrinology

Background:

• Estrogen receptor (ER) binding to estrogen response elements (EREs) is crucial for regulating gene expression.
• The specific sequence of an ERE can influence the efficiency of ER-mediated transcription.

Purpose of the Study:

• To investigate how different ERE sequences affect ER's transcriptional activity.
• To explore the impact of ERE sequence variation on ER conformation and coactivator recruitment.

Main Methods:

• Reporter plasmid assays to measure transcriptional activation by ER with various EREs (vitellogenin A2, pS2, vitellogenin B1, oxytocin).
• DNase I footprinting to assess protein protection of EREs.
• Protease digestion to analyze ER conformation changes.
• Co-immunoprecipitation and recruitment assays to evaluate coactivator binding.

Main Results:

• The consensus vitellogenin A2 ERE was the most potent activator of transcription, followed by the oxytocin ERE.
• ER conformation changed distinctly depending on the bound ERE sequence.
• Coactivators like GRIP1 and SRC-1 stabilized ER-DNA interactions, while TIF2 recruitment varied based on the ERE.

Conclusions:

• ERE sequence directly influences ER conformation, impacting coactivator protein recruitment.
• This allosteric modulation leads to differential gene expression from genes with varying ERE sequences.
• Understanding ERE-specific regulation is key to deciphering complex estrogen-mediated gene control.