Description
Key facts
Detection method:Colorimetric,
Sample types:Nuclear Extracts,
Reacts with:Mouse, Rat, Human,
Assay type:Semi-quantitative,
Sensitivity:< 600 ng/well,
Assay time:3h 30m,
Assay Platform:Microplate reader
Product details:
Estrogen Receptor Transcription Factor Assay Kit (Colorimetric) (ab207203) is a high throughput assay to quantify Estrogen Receptor (ER) activation in nuclear extracts. This assay combines a quick ELISA format with a sensitive and specific non-radioactive assay for transcription factor activation.
A specific double stranded DNA sequence containing the Estrogen Receptor consensus binding site (5' –GGTCACAGTGACC– 3') has been immobilized onto a 96-well plate. Active Estrogen Receptor present in the nuclear extract specifically binds to the oligonucleotide. Estrogen Receptor is detected by a primary antibody that recognizes an epitope of Estrogen Receptor accessible only when the protein is activated and bound to its target DNA. An HRP-conjugated secondary antibody provides sensitive colorimetric readout that at OD 450 nm. This product detects human, mouse and rat Estrogen Receptor.
Key performance and benefits:
Assay time: 3.5 hours (cell extracts preparation not included).
Detection limit: < 0.6 μg nuclear extract/well.
Detection range: 0.6 – 20 μg nuclear extract/well.
ER belongs to the superfamily of ligand-inducible transcription factors. Human ERa is comprised of 595 amino acids and displays an approximate molecular weight of 66-70 kDa. Six functional regions have been identified. A hypervariable domain (aa 1-184) contains activation function 1 (AF1). The DNA binding domain (DBD, aa 185-263) contains two zinc finger motifs and is highly conserved across the nuclear receptor superfamily. It is responsible for the binding of the receptor to estrogen response elements (EREs) and contributes to dimerization and activation. Typically, EREs consist of two inverted half-sites separated by 3 bp (5´-GGTCAnnnTGACC-3´). The region which separates the ligand binding domain (LBD) and the DBD is called the hinge region (aa 264-302).
The LBD (aa 303-553) consists of 12 a-helices, which form a hydrophobic pocket responsible for ligand binding. The function of the final domain (aa 554-595) is not clear but is thought to play a role in distinguishing between agonist and antagonist binding. Human ERb is expressed as multiple isoforms. Structure and function studies have shown that the DBD of ERa and ERb are highly homologous, approaching 96%, whereas the LBD showed only 59% homology. The general mechanism of action of ERb is thought to be similar to that of ERa. ERa and ERb have the ability to interact with target promoters in three different complexes: ERa homodimers, ERb homodimers and ERa/ERb heterodimers.
The transcriptional effects of ER can be mediated through several mechanisms other than E
-ER complexes binding to EREs. E
-ER complexes can also trans activate genes through protein-protein interactions with transcription factors such as AP-1 or Sp1 that bind DNA, with coaccessory proteins (Src, ACTR), some of which have histone acetylase activity, and with RNA Polymerase II complex proteins. In addition, ERs serve to repress genes, which also plays an important role in E
action.
Properties and Storage Information:
Shipped at conditions-Dry Ice, Appropriate short-term storage conditions-Multi, Appropriate long-term storage conditions-Multi, Storage information-Please refer to protocols
Supplementary Information:
This supplementary information is collated from multiple sources and compiled automatically.
The Estrogen Receptor (ER) also known by its alternate names NR3A1 (nuclear receptor subfamily 3 group A member 1) is a nuclear hormone receptor that binds estrogens such as the 17 beta estradiol molecule. Its molecular mass is approximately 66 kDa. This receptor locates mainly in the cytoplasm and nucleus of cells within tissues such as the breast uterus and bone. The ER exists in two primary subtypes ER alpha and ER beta which differ in their tissue distribution and functional roles.
Biological function summary
The Estrogen Receptor functions as a transcription factor that regulates gene expression when it binds to its ligand which is commonly estradiol. Upon binding 17 beta estradiol the receptor dimerizes and interacts with specific DNA sequences to influence transcription. It significantly regulates genes responsible for cell growth differentiation and reproductive functions. The estradiol chemical structure allows for specific interactions with ER altering the transcriptional regulation in a ligand-dependent manner. Though functioning mainly as a monomer ER can form heterodimers with other nuclear receptors affecting its biological role.
Pathways
The Estrogen Receptor is an important player in the genomic signaling pathway where it modulates the expression of numerous target genes by direct DNA binding. It also participates in the non-genomic signaling pathway where it involves the activation of second messengers and kinases. ER closely associates with important proteins such as coactivators and corepressors in these pathways. Estradiol chemical formula interactions facilitate molecular events involving ER-alpha to influence components of cell proliferation and survival.
The Estrogen Receptor is intricately linked to breast cancer and osteoporosis. Dysfunction in ER signaling promotes the proliferation of breast cancer cells often requiring targeted therapies that inhibit its action. In osteoporosis ER activity impacts bone density and turnover through regulation of osteoclasts and osteoblasts. The receptor's interaction with growth factor receptors like HER2 in breast cancer further highlights its significance in disease pathogenesis.
