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Detecting the Ligand-binding Domain Dimerization Activity of Estrogen Receptor Alpha Using the Mammalian Two-Hybrid Assay
Published on: December 19, 2018
Coactivator function defines the active estrogen receptor alpha cistrome.
Mathieu Lupien1, Jérôme Eeckhoute, Clifford A Meyer
1Division of Molecular and Cellular Oncology, Department of Medical Oncology, Dana-Farber Cancer Institute, 44 Binney St., Boston, MA 02115, USA.
Molecular and Cellular Biology
|April 15, 2009
Summary
Estrogen receptor alpha (ERalpha) activation in breast cancer cells is specific, driven by coactivator-associated arginine methyltransferase 1 (CARM1) at ERalpha-bound enhancers, influencing gene expression.
Area of Science:
- Molecular Biology
- Genomics
- Cancer Research
Background:
- Transcriptional networks are crucial for cellular responses to stimuli in complex organisms.
- Estrogen receptor alpha (ERalpha) plays a significant role in various biological processes, including breast cancer development and progression.
Purpose of the Study:
- To investigate the mechanisms underlying the specific transcriptional response to estradiol (E2) in MCF7 breast cancer cells.
- To elucidate the role of ERalpha cistrome subsets and coactivator-associated arginine methyltransferase 1 (CARM1) in E2-regulated gene expression.
Main Methods:
- Analysis of the estrogen receptor alpha (ERalpha) cistrome in MCF7 cells.
- Investigating the impact of estradiol (E2) on gene expression and enhancer activity.
- Assessing the role of coactivator-associated arginine methyltransferase 1 (CARM1) and FoxA1 in E2 response.
- Mapping the RNA polymerase II cistrome in MCF7 cells.
Main Results:
- Selective activation of a subset of the ERalpha cistrome provides specificity to the E2 response in breast cancer cells.
- E2-stimulated gene expression is critically dependent on ERalpha-specific enhancers modulated by CARM1, irrespective of FoxA1.
- E2-suppressed genes are linked to FoxA1-independent ERalpha binding sites with E2-induced CARM1 activity.
- RNA polymerase II shows preferential occupancy at E2-regulated promoters before stimulation, with suppressed genes often in silent genomic regions.
Conclusions:
- The transcriptional response to E2 in breast cancer cells is orchestrated by the interplay between pre-occupied promoters by RNA polymerase II and a specific subset of the ERalpha cistrome associated with coactivation.
- CARM1 action on ERalpha-bound enhancers is a key determinant of E2-stimulated gene expression, highlighting its importance in breast cancer biology.
- Understanding these regulatory mechanisms offers potential targets for therapeutic interventions in estrogen-dependent breast cancers.
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