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Determinants contributing to estrogen-regulated expression of SK3
David Jacobson1, David Pribnow, Paco S Herson
1Vollum Institute, Oregon Health and Sciences University, Portland, OR 97201, USA.
Biochemical and Biophysical Research Communications
|March 28, 2003
Summary
Estrogen regulates the rSK3 gene by interacting with estrogen receptor alpha (ER alpha) and Sp1. This interaction activates an enhancer region, influencing small conductance Ca(2+)-activated K(+) channel gene expression.
Area of Science:
- Molecular Biology
- Endocrinology
- Neuroscience
Background:
- The rSK3 gene encodes a small conductance Ca(2+)-activated K(+) channel.
- Estrogen is known to transcriptionally regulate the rSK3 gene.
Purpose of the Study:
- To identify the regulatory elements and mechanisms controlling rSK3 gene expression.
- To investigate the role of estrogen receptor alpha (ER alpha) in rSK3 gene regulation.
Main Methods:
- Promoter and enhancer identification in L6 and Cos7 cells.
- Reporter gene assays to assess transcriptional activity.
- Nuclear protein binding assays (electrophoretic mobility shift assays) to identify transcription factors.
Main Results:
- A 33 bp sequence adjacent to the rSK3 promoter functions as an enhancer in ER alpha-positive cells.
- Estrogen (17 beta-estradiol) and ER alpha activate the enhancer in Cos7 cells, inducing endogenous SK3 gene expression.
- Sp1 and Sp3 transcription factors bind to the enhancer, with ER alpha enhancing Sp1 binding affinity.
Conclusions:
- Estrogen-mediated regulation of SK3 gene expression involves the interaction between ER alpha and Sp1.
- ER alpha and Sp1 binding to the enhancer are critical for modulating rSK3 gene transcription.