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Proceedings of the National Academy of... Nov 1994We have identified a low-affinity (type II) estrogen-binding site (EBS) that is expressed at high levels during pregnancy in rat uteri. Although this activity was...
We have identified a low-affinity (type II) estrogen-binding site (EBS) that is expressed at high levels during pregnancy in rat uteri. Although this activity was detectable in nonpregnant rat uteri, it was present in amounts (0.094 pmol/g of uteri) that were severalfold lower than the high-affinity type I estrogen receptor (0.57 pmol/g of uteri). During pregnancy, at 19-20 days of gestation, the low-affinity type II EBS became the major (> or = 88%) estrogen-binding site in rat uteri. The increase in the level of low-affinity EBS (7.9 pmol/g) in uteri was approximately 85-fold with an approximately 20-fold increase in the specific activity (0.39 pmol/mg) of this form, whereas the high-affinity form remained relatively unchanged. We report here a method of purification of type II EBS from pregnant rat uteri and present an analysis of its DNA and steroid-binding properties. Estradiol-binding studies and Scatchard analysis showed that the type II EBS had an apparent estradiol-binding affinity of > or = 24 nM. Gel filtration and SDS/PAGE analysis indicated that the type II EBS was a monomeric 73-kDa protein. The estradiol binding remained apparently uninhibited in the presence of a large excess of tamoxifen, nafoxidine, or dihydrotestosterone. Estradiol, diethylstilbestrol, and quercitin (a type II EBS-specific inhibitor) competed efficiently. The purified low-affinity EBS did not have sequence-specific DNA-binding activity with the estrogen-responsive element, which indicated that it differs in function from the type I estrogen receptor.
Topics: Animals; Base Sequence; Binding, Competitive; DNA; DNA-Binding Proteins; Estradiol; Estrogens; Female; Molecular Sequence Data; Pregnancy; Rats; Receptors, Estrogen; Uterus; alpha-Fetoproteins
PubMed: 7526397
DOI: 10.1073/pnas.91.24.11502 -
The Biochemical Journal Sep 1981We show that a mouse uterus nuclear phosphatase exists that is capable of inactivating nuclear oestrogen receptor complexed to oestradiol-17 beta in vitro but is... (Comparative Study)
Comparative Study
We show that a mouse uterus nuclear phosphatase exists that is capable of inactivating nuclear oestrogen receptor complexed to oestradiol-17 beta in vitro but is ineffective when the receptor is complexed with the two non-steroidal anti-oestrogens, nafoxidine and tamoxifen. We suggest that the long half-life of the tamoxifen-receptor complex versus the short half-life of the oestradiol-receptor complex in uterine nuclei in vivo is the result of the ineffectiveness of the phosphatase in dephosphorylating the anti-oestrogen-receptor complex.
Topics: Animals; Cattle; Cell Nucleus; Cytosol; Estradiol; Female; Half-Life; In Vitro Techniques; Mice; Nafoxidine; Phosphoric Monoester Hydrolases; Pyrrolidines; Receptors, Estradiol; Receptors, Estrogen; Tamoxifen; Uterus
PubMed: 6275856
DOI: 10.1042/bj1980699 -
British Journal of Pharmacology Jan 1980
Topics: Animals; Estrogen Antagonists; Female; In Vitro Techniques; Nafoxidine; Naphthalenes; Pyrrolidines; Rats; Receptors, Progesterone
PubMed: 7357169
DOI: No ID Found -
Proceedings of the National Academy of... Apr 1991We describe in this report experiments in vivo that demonstrate that antiestrogens promote DNA binding of the estrogen receptor without efficiently inducing...
We describe in this report experiments in vivo that demonstrate that antiestrogens promote DNA binding of the estrogen receptor without efficiently inducing transcription. When the receptor is modified to carry a foreign unregulated transactivation domain, transcription can be induced efficiently by both estrogen and antiestrogens. Under apparent saturation conditions, antihormone-receptor complexes binding to responsive enhancer elements elicit only a low level of transcription. In addition, we show that both estrogen and an antiestrogen, nafoxidine, effect very similar alterations in chromatin structure at a responsive promoter. These results indicate that in vivo steroid receptor action can be regulated subsequent to the DNA binding step, by regulating interactions with the target transcriptional machinery. In this regard, antihormones can function by establishing receptor-DNA complexes that are transcriptionally nonproductive.
Topics: Chromatin; Cloning, Molecular; DNA-Binding Proteins; Enhancer Elements, Genetic; Estradiol; Estrogen Antagonists; Gene Expression Regulation; Humans; In Vitro Techniques; Receptors, Estrogen; Recombinant Fusion Proteins; Saccharomyces cerevisiae; Signal Transduction; Structure-Activity Relationship; Transcription, Genetic; Transfection
PubMed: 2014231
DOI: 10.1073/pnas.88.8.3125 -
The Biochemical Journal Dec 1972The effect of oestradiol treatment on the acetylation of histones of the immature rat uterus has been studied. A 10mug dose of oestradiol causes a 70% increase at 5min...
The effect of oestradiol treatment on the acetylation of histones of the immature rat uterus has been studied. A 10mug dose of oestradiol causes a 70% increase at 5min and a 140% increase at 10min after administration in the labelling of the histone fraction F2+F3. No effect of oestradiol is seen on the labelling of histones F1 or acidic non-histone chromatin proteins. The oestradiol stimulation is seen in animals pretreated with either cycloheximide or actinomycin D. The stimulation of labelling caused by oestradiol is completely abolished by pretreatment of the animals with the anti-oestrogen, nafoxidine. The stimulation is given by lower doses of oestradiol, by stilboestrol and oestriol, but is not given by testosterone. These results suggest that stimulation of histone acetylation in the uterus is the earliest known effect of the hormone on its target tissue.
Topics: Acetates; Acetylation; Animals; Anti-Bacterial Agents; Chromatin; Cycloheximide; Dactinomycin; Diethylstilbestrol; Estradiol; Estriol; Estrogen Antagonists; Female; Histones; Liver; Naphthalenes; Phenols; Pyrrolidines; Rats; Stimulation, Chemical; Testosterone; Tritium; Uterus
PubMed: 4664926
DOI: 10.1042/bj1300663 -
British Medical Journal Jun 1974
Topics: Antineoplastic Agents; Breast Neoplasms; Dimethylamines; Estrogen Antagonists; Female; Humans; Menopause; Nafoxidine; Phenyl Ethers; Receptors, Cell Surface; Stilbenes; Time Factors
PubMed: 4365448
DOI: 10.1136/bmj.2.5917.500 -
British Medical Journal Mar 1974
Clinical Trial
Topics: Aged; Breast Neoplasms; Estrogens; Ethinyl Estradiol; Female; Humans; Menopause; Middle Aged; Nafoxidine
PubMed: 4819183
DOI: 10.1136/bmj.1.5904.390 -
British Medical Journal May 1974
Topics: Breast Neoplasms; Estrogen Antagonists; Female; Humans; Menopause; Nafoxidine; Pyrrolidines
PubMed: 4835320
DOI: 10.1136/bmj.2.5916.447