Could estrogen impact a new pertinent gene for AIS?

Molecular and Cellular Endocrinology, 2007

Estrogen-related receptor alpha (ERR␣) modulates estrogen receptor (ER)-mediated activity and is participating in the energy homeostasis by regulation of downstream target genes. The ERR␣ gene itself is proposed to be regulated by peroxisome proliferator-activated receptor ␥ coactivator (PGC-1␣) through an autoregulatory loop under physiological stimulation. We have previously shown that the close family member ERR␥ is a positive regulator of ERR␣ gene expression. ERR␣ and ERR␥ are coexpressed in metabolically active tissues such as heart, kidney and muscle, yet the physiological role of ERR␥ and its relationship with ERR␣ in gene regulation are currently unknown. The present study examined the interplay of ERR␥ and ERR␣ in regulation of ERR␣ gene expression. Using real-time PCR analyses we found that ERR␥, like the ERR␣ and PGC-1␣ is induced in mouse liver during fasting. Overexpression of ERR␥ in the HEC-1B cells robustly stimulated the multi-hormone response element (MHRE) of the ERR␣ gene promoter and this activity was repressed by increasing expression of ERR␣. The two ERRs bind MHRE simultaneously in electrophoretic mobility shift assay (EMSA) and they were detected as multimeric complexes in cells by coimmunoprecipitation. Although ERR␣ and ERR␥ share high sequence identity, they differ in biochemical and molecular characteristics as examined by trypsin digestion, reporter activation and coactivator interaction and utilization. Using chromatin immunoprecipitation (ChIP) assay, we showed that ectopic expression of both ERR␣ and ERR␥ modifies chromatin structure at the MHRE region while ectopic expression of PGC-1␣ in HEC-1B cells promotes ERR␥ but not ERR␣ occupancy at the MHRE region of the ERR␣ gene promoter and enhances the recruitment of coactivator SRC1. These data suggested that ERR␣ and ERR␥ regulate ERR␣ gene expression with different molecular mechanisms.

Biology Open

The physiological role and the regulation of ADGRG7 are not yet elucidated. The functional involvement of this receptor was linked with different physiological process such as reduced body weight, gastrointestinal function and recently, a gene variant in ADGRG7 was observed in patients with adolescent idiopathic scoliosis. Here, we identify the ADGRG7 as an estrogen-responsive gene under the regulation of estrogen receptor ERα in scoliotic osteoblasts and other cells lines. We found that ADGRG7 expression was upregulated in response to estrogen (E2) in adolescent idiopathic scoliosis (AIS) cells. ADGRG7 promoter studies indicate the presence of an ERα response half site in close vicinity of a specificity protein 1 (SP1) binding site. Mutation of the SP1 site completely abrogated the response to E2, indicating its essential requirement. ChIP confirmed the binding of SP1 and ERα to the ADGRG7 promoter. Our results identify the ADGRG7 gene as an estrogen-responsive gene under the control of ERα and SP1 tethered actions, suggesting a possible role of estrogens in the regulation of ADGRG7.

Molecular Endocrinology, 2006

The orphan nuclear receptor estrogen-related receptor ␣ (ERR␣, NR3B1) is a constitutively active transcription factor that controls multiple processes, most notably mitochondrial function. ERR␣ preferentially binds to a nine-nucleotide extended half-site sequence TNAAGGTCA, referred to as the ERRE, as either a monomer or a dimer, although how the mode of DNA binding is dictated remains to be determined. Here, we used variants of the extended half-site sequence and selective DNA binding domain mutants of ERR␣ to investigate the effects of ERRE sequence specificity on ERR␣ DNA binding mode, transactivation and interaction with the coactivator protein peroxisome proliferator-activated receptor ␥ coactivator 1␣ (PGC-1␣). We found that the base at the N position of the TNAAGGTCA sequence dictated ERR␣ binding preference as a monomer or dimer. In addition, we demonstrated that the threonine residue at position 124 (Thr 124) was a determinant of ERR␣ DNAdependent dimerization. Transfection experiments also indicated that substituting a thymidine for a cytosine at the N position in the ERRE of the native ERR␣ target promoter trefoil factor 1 (TFF1) considerably diminished the transcriptional response of the ERR␣/PGC-1␣ complex. These results suggest that a single nucleotide in an ERR␣ binding site can determine specific configuration to the receptor and productive interaction with the coactivator PGC-1␣. (Molecular Endocrinology 20: 302-310, 2006)

The Journal of Steroid Biochemistry and Molecular Biology, 1997

The presence or absence of estrogen receptor (ER) plays a key role in the diagnosis and treatment of breast tumors. It is known that patients with breast tumors classified as ER-positive have a better prognosis. Observations such as this have led us to explore the question of what makes some breast tumors overexpress ER whereas others express either very low levels or none at all. To begin a study of ER regulation, we first chose to examine a 200 bp region of the ER promoter located immediately upstream from the transcribed sequence of the human ER gene. We found that this region of the ER promoter contained basal activity when transiently transfected into ER-negative HeLa cells. ER promoter activity was further increased by co-transfection of a wild-type ER expression vector, and this increased activity was hormone-dependent. Several ER deletion mutant constructs were also able to increase the activity of the ER promoter fragment, but none could support equivalent activity as was seen with the full-length ER. Therefore, we conclude that the ER can contribute to its own expression, and we hypothesize that this auto-regulation may contribute to its overexpression in some breast tumors.

The EMBO Journal, 1999

The physiological activities of estrogens are thought to be mediated by specific nuclear receptors, ERα and ERβ. However, certain tissues, such as the bone, that are highly responsive to estrogens only express a low level of these receptors. Starting from this apparent contradiction, we have evaluated the potentials of two related receptors ERRα and ERRβ to intervene in estrogen signaling. ERα, ERRα and ERRβ bind to and activate transcription through both the classical estrogen response element (ERE) and the SF-1 response element (SFRE). In contrast, ERβ DNA-binding and transcriptional activity is restricted to the ERE. Accordingly, the osteopontin gene promoter is stimulated through SFRE sequences, by ERRα as well as by ERα, but not by ERβ. Analysis of the cross-talk within the ER/ERR subgroup of nuclear receptors thus revealed common targets but also functional differences between the two ERs.

Frontiers in Bioscience

Introduction 3. ERα Structure 3.1. The Structure of the ERα-LBD 3.2. The Structure of the ERα-DBD 3.3. The Structure of the ERα amino-terminus 4. Nuclear E2-ERα signaling 4.1. Pioneering Factors and ERBSs 4.2. ERα-Mediated ERE-Dependent Signaling 4.3. ERα-Mediated ERE-Independent Signaling 4.4. The Importance of the ERE-dependent signaling pathway in cellular responses 5. Enhancer RNAs (eRNAs) and ERα signaling 6. Transcription-coupled DNA repair and ERα signaling 7. R-loops, DNA breaks and transcription 8. Conclusions 9. Acknowledgments 10. References

Endocrinology, 2000

To investigate the estrogenic effects on the transcriptional regulation of the epidermal growth factor (EGF) receptor (EGFR) gene, we assayed its promoter ability to direct transcription of the luciferase reporter gene after transfection into HeLa cells. Our studies demonstrated a dose-dependent activation of the EGFR gene transcription by ligand-bound estrogen receptor α (ERα). This action was retained by the 36-bp core promoter fragment and did not require the receptor DNA binding domain, as demonstrated by analyzing the role of ERα deletion mutants on EGFR gene promoter-derived constructs. The 36-bp promoter fragment does not contain an estrogen response element but an imperfect thyroid hormone response element half-site that overlaps the Sp1 binding site. ERα does not bind this imperfect thyroid hormone response element half-site but is able to enhance binding of Sp1 to its site, in gel mobility shift assays, suggesting that the mechanism by which the receptor stimulated the tra...

Steroids, 2012

Estrogens exert their effect through ERa and ERb intracellular transcription factors and rapid, usually membrane-initiated receptors, influencing cytosolic signaling and transcription. The nature of extranuclear estrogen elements has not been elucidated so far; classical or alternatively transcribed ER isoforms (ERa36, ERa46) anchored to the plasma membrane and GPR30 (GPER1) have been reported to exert early estrogen actions. Here, we used E2-BSA, an impermeable estradiol analog for a transcriptome analysis in four GREP1 positive breast cancer cell lines with different estrogen receptor profiles (T47D, MCF-7, MDA-MB-231 and SKBR3) in order to evaluate GPER1 transcriptional effects. Early effects of E2-BSA were assayed after 3 h of incubation, in the absence/presence of ICI182,780 (ER-inhibitor) or G15 (GREP1specific inhibitor). E2-BSA specifically modified 277-549 transcripts in the different cell lines. Two different clusters of transcripts could be identified: (1) the majority of transcripts were inhibited by both ICI182,780 and G15, suggesting an interaction of E2-BSA with a common ER-related element, or a direct ER-GPER1 interaction; (2) a small number of G15-only modified transcripts, in two cell lines (T47D and SKBR3 cells), indicative of specific GPER1-related effects. The latter transcripts were significantly related to pathways including FOXA2/FOXA3 transcription factor networks, RNA-Polymerases Transcription Regulation and lipid metabolism, while ICI/G15 inhibited transcripts affected pathways related to apoptosis, erythropoietin signaling, metabolic effects through the citric acid cycle, IL-4 and IL-5 mediated events and homologous DNA recombination. Finally, we review the current literature of GPER1 actions, in view of our results of ER-dependent and independent GPER1-modified pathways.

Endocrinology, 2002

Chronic treatment of fetal rat calvaria cells with E2stimulated bone nodule formation and up-regulated ERR␣ mRNA expression at early (10 h and d 8) but not later times in culture, suggesting a link between ERR␣ and E2 during osteoprogenitor proliferation. ERR␣ mRNA levels were significantly lower in ovariectomized adult rat bones vs. those of sham-operated rats early (1 d and 1 wk) post surgery, but levels returned to control levels thereafter. ERR␣ is also ex-pressed in osteoclasts (tartrate-resistant acid phosphatase ؉ multinucleated cells) in vivo and in vitro (RAW 264.7 cells) and ovariectomization lowered the OPG/receptor activator of nuclear factor B ligand expression ratio. Down-regulation of ERR␣ expression via antisense treatment of rat calvaria cells not only inhibited osteogenesis but also increased adipocyte colony formation and changed the OPG/receptor activator of nuclear factor B ligand ratio. These data suggest that ERR␣ is regulated by estrogen in bone in which it may play a functional role at several levels (osteoblasts, adipocytes, and osteoclasts) in E2 deficiency diseases such as osteoporosis. (Endocrinology 143: 3658 -3670, 2002) N UCLEAR RECEPTORS ARE transcription factors involved in various physiological regulatory processes.

Journal of Biological Chemistry, 2000

17␤-Estradiol (E2) induces expression of several genes via estrogen receptor (ER)-Sp1 protein interactions with GC-rich promoter elements in which Sp1 but not ER binds DNA. This study reports the ligand-and cell context-dependent ER ␣ /Sp1 and ER ␤ /Sp1 action using an E2-responsive construct (pSp1) containing a GC-rich promoter. Both ER ␣ and ER ␤ proteins physically interact with Sp1 (coimmunoprecipitation) and preferentially bind to the C-terminal region of this protein in pull-down assays. E2-and antiestrogen-dependent transcriptional activation of ER ␣ /Sp1 was observed in MCF-7, MDA-MB-231, and LnCaP cells, but not in HeLa cells. E2 did not affect or significantly decrease ER ␤ /Sp1 action, and antiestrogens had minimal effects in the same 4 cell lines. Exchange of activation function-1 (AF-1) domains of ER subtypes gave chimeric ER ␣/␤ (AF-1␣/AF-2␤) and ER ␤/␣ (AF-1␤/AF-2␣) proteins that resembled wild-type ER (␣ or ␤) in terms of physical association with Sp1 protein. Transcriptional activation studies with chimeric ER ␤/␣ and ER ␣/␤ showed that only ER ␣/␤ can activate transcription from an Sp1 element, not ER ␤/␣. This indicates that the AF-1 domain from ER ␣ is responsible for activation at an Sp1 element, independent of ER subtype context. In order to further characterize this observation, deletion constructs in the AF-1 domain of both ER ␣ and ER ␣/␤ were made, and transactivation studies indicated that the region between amino acids 79 and 117 of this domain is important for activation at an Sp1 element.