Estrogen receptor binding to a DNA response element in vitro is not dependent upon estradiol

Murdoch, Fern E.; Meier, Daniel A.; Furlow, J. David; Grunwald, Kurt A. A.; Gorski, Jack

doi:10.1021/bi00488a026

Cited by 103 publications

(71 citation statements)

References 52 publications

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“…4). These findings are generally consistent with the results of previous experiments on the binding of ER (in the absence of associated heat shock proteins) to naked DNA in vitro (see, e.g., Murdoch et al 1990;Furlow et al 1993;Metzger et al 1995;Cheskis et al 1997). We do not, however, extrapolate these data to the behavior of ER in vivo, as these experiments with free polypeptide ER do not involve issues such as the association of heat shock proteins with ER and nuclear localization.…”

Section: Relation Between Binding Of Er To Chromatin and Transcriptiosupporting

confidence: 92%

p300 and estrogen receptor cooperatively activate transcription via differential enhancement of initiation and reinitiation

Kraus¹,

Kadonaga²

1998

Genes & Development

313

246

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Estrogen-and antiestrogen-regulated, AF-2-dependent transcriptional activation by purified full-length human estrogen receptor (ER) was carried out with chromatin templates in vitro. With this system, the ability of purified human p300 to function as a transcriptional coactivator was examined. In the absence of ligand-activated ER, p300 was found to have little effect (less than twofold increase) on transcription, whereas, in contrast, p300 was observed to act synergistically with ligand-activated ER to enhance transcription. When transcription was limited to a single round, p300 and ER were found to enhance the efficiency of transcription initiation in a cooperative manner. On the other hand, when transcription reinitiation was allowed to occur, ER, but not p300, was able to increase the number of rounds of transcription. These results suggest a two-stroke mechanism for transcriptional activation by ligand-activated ER and p300. In the first stroke, ER and p300 function cooperatively to increase the efficiency of productive transcription initiation. In the second stroke, ER promotes the reassembly of the transcription preinitiation complex. Therefore, ER exhibits distinct, dual functions in transcription initiation and reinitiation.

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Section: Relation Between Binding Of Er To Chromatin and Transcriptiosupporting

confidence: 92%

p300 and estrogen receptor cooperatively activate transcription via differential enhancement of initiation and reinitiation

Kraus¹,

Kadonaga²

1998

Genes & Development

313

246

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“…Binding of ER to 32 P-ERE-containing oligonucleotide was detected in the nuclear extract prepared from cells grown in E2-free medium in the absence of E2, suggesting that ER⅐ERE interaction in this reconstitution system is independent of E2, as has been observed by other investigators (30). Stimulation by E2 of ER-32 P-ERE binding was detected when hormonetreated, ERϩ MCF-7 cells (with native ER) were used to prepare nuclear extracts (Fig.…”

Section: Cam Is An Integral Component Of the Er⅐ere Complex-wesupporting

confidence: 77%

Calmodulin Is Essential for Estrogen Receptor Interaction with Its Motif and Activation of Responsive Promoter

Biswas¹,

Reddy²,

Pickard³

et al. 1998

Journal of Biological Chemistry

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Calmodulin (CaM) has been reported to have affinity for the estrogen receptor (ER). Observations reported here reveal a direct physical interaction between purified CaM and ER. This direct ER-CaM interaction may be an initial event preceding the assembly of ER plus auxiliary proteins into the active ER complex with its DNA motif, the estrogen response element. We demonstrate that CaM is an integral component of this complex by using a system reconstituted from purified ER and nuclear extract from ER-negative breast cancer cells and also with ER-depleted nuclear extract of an ER-positive breast cancer cell line. Although CaM is essential for formation of this complex, it is not sufficient, suggesting roles also of auxiliary proteins. CaM also is functionally required for activation of an ER-responsive promoter, in the 17␤-estradiol-ER pathway of hormone action and regulation of 17␤-estradiol-responsive gene expression that is associated with proliferation of mammary epithelial cells. CaM1 plays a pivotal role in the proliferation of a variety of cells. Several observations indicate CaM involvement in estrogen regulation of breast cancer cell growth. Calcium homeostasis is lost (1), and expression of calcium binding proteins is modulated (2-4). There is an overall increase of Ca 2ϩ levels in human mammary tumors (5, 6), and CaM concentrations are 2-3-fold higher in estrogen receptor-positive (ERϩ) than in estrogen receptor-negative (ERϪ) breast tumors (7). The growth of breast cancer cells is highly sensitive to anti-calmodulin drugs (8, 9), and the anti-estrogen Tamoxifen binds to CaM with high affinity and antagonizes its action (10). CaM also modulates estrogen (17␤-estradiol (E2)) binding to ER (11), and synergistic inhibition of growth by CaM inhibitors and antiestrogens (12, 13) are associated with breast cancer.Both anti-estrogens and anti-calmodulin drugs block breast cancer cells at an identical point in the G 1 phase of the cell cycle (14). Furthermore, CaM is known to stimulate the phosphorylation of estrogen receptors (15). Biochemical evidence suggests an interaction of CaM with ER (11, 16 -19), but these results did not demonstrate a direct physical contact.We examined more directly the possibility of a role of CaM in key downstream events of E2 action, i.e. the interaction of ER protein with its cognate DNA sequence (estrogen response element (ERE)) to form the ER⅐ERE complex and the resulting transactivation of an E2-responsive promoter. We observed that CaM directly interacts with ER, and is not only an integral component of the ER⅐ERE complex but also plays an essential role in complex formation. Its functional involvement in the molecular pathway of E2-induced transactivation of hormoneresponsive genes in breast cancers was tested. EXPERIMENTAL PROCEDURESCell Lines and Culture-MCF-7 and MDA-MB-231 cell lines were obtained from ATCC and were grown in rich medium (Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum, 2.8 M hydrocortisone, 1 g/ml insulin, and 12.5 ng/ml epide...

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“…Most studies quantitating ER-ERE binding affinity have used short synthetic oligomers (Murdoch et al 1990, Augereau et al 1994, Arnold et al 1996, Anderson et al 1998, Driscoll et al 1998, Boyer et al 2000. Here we used longer restriction fragments in which the ERE is embedded within plasmid DNA, a situation that more closely approximates the context of an ERE within a gene promoter, but eliminates the confounding effect of binding sites for other transcription factors, therefore giving a neutral background.…”

Section: Discussionmentioning

confidence: 99%

Response element sequence modulates estrogen receptor alpha and beta affinity and activity

Kulakosky

McCarty

Jernigan

et al. 2002

Journal of Molecular Endocrinology

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The relationship between estrogen receptor (ER)-estrogen response element (ERE) binding affinity and estradiol (E 2 )-induced transcription has not been systematically or quantitatively tested. We examined the influence of ERE palindrome length and the 3′ ERE flanking sequence on ERα and ERβ affinity binding in vitro and on the induction of reporter gene activity in transfected cells. The addition of one nucleotide in each arm of the 13 bp ERE palindrome, forming a 15 bp ERE palindrome, increased ERα and ERβ affinity and transcription. In contrast, the addition of an AT-rich flanking sequence from genes highly stimulated by E 2 had little effect on affinity or reporter gene activity. Notable differences between ERα and ERβ include: both K d and transcriptional induction were generally higher for ERα than ERβ, better correlation between ERE palindrome length and transcriptional induction for ERα than ERβ, and a better correlation between (ER-ERE) K d and transcriptional induction for ERα than for ERβ.

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Estrogen receptor binding to a DNA response element in vitro is not dependent upon estradiol

Cited by 103 publications

References 52 publications

p300 and estrogen receptor cooperatively activate transcription via differential enhancement of initiation and reinitiation

p300 and estrogen receptor cooperatively activate transcription via differential enhancement of initiation and reinitiation

Calmodulin Is Essential for Estrogen Receptor Interaction with Its Motif and Activation of Responsive Promoter

Response element sequence modulates estrogen receptor alpha and beta affinity and activity

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