Expression of Estrogen Receptor-  Protein in Rodent Ovary

Fitzpatrick, Shannon L.

doi:10.1210/en.140.6.2581

Cited by 63 publications

(79 citation statements)

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“…ERβ was expressed almost exclusively in granular cells suggesting the possibility that the estrogen action may be mediated primarily by ERβ in the ovary of the Mongolian gerbil. This result is similar to that reported for rats [3,8]. Also, the finding that the expected ERβ PCR product was not satisfactorily generated from reverse transcribed mRNA from the uterus of the Mongolian gerbil is consistent with other work [32].…”

Section: Discussionsupporting

confidence: 91%

Effects of Levonorgestrel on Reproductive Hormone Levels and Their Receptor Expression in Mongolian Gerbils (Meriones unguiculatus)

Shi

2011

Exp. Anim.

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Abstract:The effects of levonorgestrel (LNG) on serum levels of reproductive hormones and their receptor mRNA expression in the ovary and uterus of Mongolian gerbils were examined. The results show that serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) increased, whereas serum estradiol (E2) and progesterone (P4) decreased profoundly after LNG treatment. LNG down-regulated the mRNA expression of folliclestimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR), estrogen receptor (ER) β and progesterone receptor (PR) in the ovary, and ERα and PR in the uterus of Mongolian gerbils. The down-regulated effects were time-dependent and dose-dependent. LNG had no obvious effects on ERα mRNA expression in the ovary. The findings suggest that LNG impairs reproductive hormone receptor expression at the molecular level in Mongolian gerbils. Also, the two ER subtypes may play different roles in the ovary, and ERβ may not be the predominant ER subtype in the uterus of Mongolian gerbils. The ovary and uterus may be the important sites of action of LNG through its direct progesterone-like effects in Mongolian gerbils.

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Section: Discussionsupporting

confidence: 91%

Effects of Levonorgestrel on Reproductive Hormone Levels and Their Receptor Expression in Mongolian Gerbils (Meriones unguiculatus)

Shi

2011

Exp. Anim.

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“…As ER␤ function appears to be indispensable for normal folliculogenesis, we tested if the observed FSH-induced regulation of ER␤ target genes occurred during folliculogenesis in the intact ovary. To model the murine ovulatory cycle, we injected mice at the diestrous phase with PMSG and hCG and collected ovarian samples from immature ovaries (9,15) (Fig. 7A).…”

Section: Resultsmentioning

confidence: 99%

Coactivation of Estrogen Receptor β by Gonadotropin-Induced Cofactor GIOT-4

Kouzu-Fujita

Mezaki

Sawatsubashi

et al. 2009

Molecular and Cellular Biology

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Estrogen exerts its diverse effects through two subtypes of estrogen receptors (ER), ER␣ and ER␤. Each subtype has its own distinct function and expression pattern in its target tissues. Little, however, is known about the transcriptional regulatory mechanism of ER␤ in the major ER␤-expressing tissues. Using biochemical methods, we identified and described a novel ER␤ coactivator. This protein, designated GIOT-4, was biochemically purified from 293F cells. It coactivated ER␤ in ovarian granulosa cells. GIOT-4 expression was induced by stimulation with follicle-stimulating hormone (FSH). GIOT-4 recruited an SWI/SNF-type complex in a ligand-independent manner to ER␤ as an ER subtype-specific physical bridging factor and induced subsequent histone modifications in the ER␤ target gene promoters in a human ovarian granulosa cell line (KGN). Indeed, two ER␤-specific target genes were upregulated by FSH at a specific stage of a normal ovulatory cycle in intact mice. These findings imply the presence of a novel regulatory convergence between the gonadotropin signaling cascade and ER␤-mediated transcription in the ovary.Estrogen plays important roles in many target organs, including the female reproductive organs, the central nervous system, and bone. Estrogen exerts its diverse biological actions through binding to and activating one of two nuclear estrogen receptor (ER) subtypes (ER␣ or ER␤) (12,22,35,40). ERs are members of the nuclear receptor (NR) gene superfamily. ERs, bound to and activated by estrogen, bind to specific DNA sequences called estrogen-responsive elements (ERE) to induce target genes (14,21).Like the other NR members, the ER requires the cooperation of distinct classes of coregulators and multiprotein coregulator complexes in order to initiate estrogen-mediated chromatin reorganization (16,46). These complexes appear to modify the chromatin configuration in a highly regulated manner by controlling nucleosomal rearrangement and enzymecatalyzed modifications of histone tails. By altering chromatin structure, the coregulator complexes facilitate bridging between NRs and basal transcription factors, along with RNA polymerase II, thereby controlling transcription. As for the nucleosomal rearrangement, two major classes of chromatinmodifying complexes that coregulate NRs have been well-characterized. One class is the histone-modifying complexes, including discrete subfamilies of transcription coregulatory complexes (2,29,36). The best-characterized NR coregulator complexes possess either histone acetylase or histone deacetylase activities. Recently, histone methylases/demethylases have also been shown to be significant NR coregulators. The other class of coregulator complexes is ATP-dependent chromatinremodeling complexes. These complexes use ATP hydrolysis to rearrange nucleosomal arrays in a noncovalent manner to facilitate or prevent the access of NRs to nucleosomal DNA (5,17,33). These ATP-dependent chromatin-remodeling complexes have been classified into three subfamilies based on the major catalytic ...

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“…The high expression level of some of the ERβ mRNA splice variants suggests that if corresponding proteins are expressed, they too would be abundant. Sharma et al (1999) demonstrated that multiple ERβ variants can be seen with ERβ-specific antisera and Western blot analysis of proteins derived from ovary, a tissue known to express ERβ at high levels (Fitzpatrick et al, 1999;O'Brien et al, 1999). The distribution of at least one of these splice variants, ER-β2, has been shown in rat brain using anti-peptide antibodies directed against the unique sequence of the insert in the ligand binding domain.…”

Section: Erβ Splice Variant Characterization and Localization In Brainmentioning

confidence: 99%

Estrogen receptor beta in the brain: From form to function

Weiser

Foradori

Handa

2008

Brain Research Reviews

194

159

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Estrogens have numerous effects on the brain, both in adulthood and during development. These actions of estrogen are mediated by two distinct estrogen receptor (ER) systems, ER alpha (ERα) and ER beta (ERβ). In brain, ERα plays a critical role in regulating reproductive neuroendocrine function and behavior, however, a definitive role for ERβ in any neurobiological function has been slow in forthcoming. Clues to the function of ERβ in the central nervous system can be gleaned from the neuroanatomical distribution of ERβ and the phenotypes of neurons that express ERβ. ERβ immunoreactivity has been found in populations of GnRH, CRH, vasopressin, oxytocin and prolactin containing neurons in the hypothalamus. Utilizing subtype-selective estrogen receptor agonists can help determine the roles for ERβ in non-reproductive behaviors in rat models. ERβ selective agonists exert potent anxiolytic activity when animals were tested in a number of behavioral paradigms. Consistent with this, ERβ selective agonists also inhibited the ACTH and corticosterone response to stress. In contrast, ERα selective agonists were found to be anxiogenic and correspondingly increased the hormonal stress response. Taken together, our studies implicate ERβ as an important modulator of some non-reproductive neurobiological systems. The molecular and neuroanatomical targets of estrogen that are mediated by ERβ remain to be determined.A number of splice variants of ERβ mRNA have been reported in brain tissue. Imaging of eGFP labeled chimeric receptor proteins transfected into cell lines show that ERβ splice variation can alter trafficking patterns and function. The originally described ERβ (herein termed ER-β1) is characterized by possessing a high affinity for estradiol. Similar to ERα, it is localized in the nucleus and is trafficked to nuclear sites termed "hyperspeckles" following ligand binding. In contrast, ER-β2 contains an 18 amino acid insert within the ligand binding domain and as a result can be best described as a low affinity form of ERβ. A delta3 (δ3) variant of ERβ has a deletion of the 3rd exon (coding for the second half of the DNA binding domain) and as a result does not bind an estrogen response element in DNA. δ3 variants are trafficked to a unique low abundance and larger nuclear site following ligand binding. A delta4 (δ4) variant lacks exon 4 and as a result is localized to the cytoplasm. The amount of individual splice variant mRNAs varies depending upon brain region. Examination of neuropeptide promoter regulation by ERβ splice variants demonstrate that ERβ functions as a constitutively active transcription factor. Moreover, it appears that splice variation of ERβ alters its ability to regulate transcription in a promoter-dependent and ligand-dependent fashion.

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Expression of Estrogen Receptor- Protein in Rodent Ovary

Cited by 63 publications

References 0 publications

Effects of Levonorgestrel on Reproductive Hormone Levels and Their Receptor Expression in Mongolian Gerbils (Meriones unguiculatus)

Effects of Levonorgestrel on Reproductive Hormone Levels and Their Receptor Expression in Mongolian Gerbils (Meriones unguiculatus)

Coactivation of Estrogen Receptor β by Gonadotropin-Induced Cofactor GIOT-4

Estrogen receptor beta in the brain: From form to function

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