| 1. |
- Lindberg, Marie K, 1975, et al.
(författare)
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Estrogen receptor (ER)-beta reduces ERalpha-regulated gene transcription, supporting a "ying yang" relationship between ERalpha and ERbeta in mice.
- 2003
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Ingår i: Molecular endocrinology (Baltimore, Md.). - : The Endocrine Society. - 0888-8809 .- 1944-9917. ; 17:2, s. 203-8
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Tidskriftsartikel (refereegranskat)abstract
- Estrogen is of importance for the regulation of adult bone metabolism. The aim of the present study was to determine the role of estrogen receptor-beta (ERbeta) in vivo on global estrogen-regulated transcriptional activity in bone. The effect of estrogen in bone of ovariectomized mice was determined using microarray analysis including 9400 genes. Most of the genes (95% = 240 genes) that were increased by estrogen in wild-type (WT) mice were also increased by estrogen in ERbeta-inactivated mice. Interestingly, the average stimulatory effect of estrogen on the mRNA levels of these genes was 85% higher in ERbeta-inactivated than in WT mice, demonstrating that ERbeta reduces estrogen receptor-alpha (ERalpha)-regulated gene transcription in bone. The average stimulatory effect of estrogen on estrogen-regulated bone genes in ERalpha-inactivated mice was intermediate between that seen in WT and ERalphabeta double-inactivated mice. Thus, ERbeta inhibits ERalpha-mediated gene transcription in the presence of ERalpha, whereas, in the absence of ERalpha, it can partially replace ERalpha. In conclusion, our in vivo data indicate that an important physiological role of ERbeta is to modulate ERalpha-mediated gene transcription supporting a "Ying Yang" relationship between ERalpha and ERbeta in mice.
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| 2. |
- Otsuki, Michio, et al.
(författare)
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Specific regulation of lipocalin-type prostaglandin D synthase in mouse heart by estrogen receptor beta.
- 2003
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Ingår i: Molecular endocrinology (Baltimore, Md.). - : The Endocrine Society. - 0888-8809 .- 1944-9917. ; 17:9, s. 1844-55
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Tidskriftsartikel (refereegranskat)abstract
- Estrogens have important physiological roles in the cardiovascular system. We use DNA microarray technology to study the molecular mechanism of estrogen action in the heart and to identify novel estrogen-regulated genes. In this investigation we identify genes that are regulated by chronic estrogen treatment of mouse heart. We present our detailed characterization of one of these genes, lipocalin-type prostaglandin D synthase (L-PGDS). Northern and Western blot analysis revealed that L-PGDS was induced both by acute and chronic estrogen treatment. Northern blot analysis, using estrogen receptor (ER)-disrupted mice, suggests that L-PGDS is specifically induced by ERbeta in vivo. In further support of ERbeta-selective regulation, we identify a functional estrogen-responsive element in the L-PGDS promoter, the activity of which is up-regulated by ERbeta, but not by ERalpha. We demonstrate that a one-nucleotide change (A to C) in the L-PGDS estrogen-responsive element affects receptor selectivity.
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| 3. |
- Saltó, C, et al.
(författare)
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Ablation of TRalpha2 and a concomitant overexpression of alpha1 yields a mixed hypo- and hyperthyroid phenotype in mice.
- 2001
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Ingår i: Molecular endocrinology (Baltimore, Md.). - : The Endocrine Society. - 0888-8809. ; 15:12, s. 2115-28
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Tidskriftsartikel (refereegranskat)abstract
- Thyroid hormone governs a diverse repertoire of physiological functions through receptors encoded in the receptor genes alpha and beta, which each generate variant proteins. In mammals, the alpha gene generates, in addition to the normal receptor TRalpha1, a non-hormone-binding variant TRalpha2 whose exact function is unclear. Here, we present the phenotype associated with the targeted ablation of TRalpha2 expression. Selective ablation of TRalpha2 resulted in an inevitable, concomitant overexpression of TRalpha1. Both TRalpha2 +/- and -/- mice show a complex phenotype with low levels of free T3 and free T4, and have inappropriately normal levels of TSH. The thyroid glands exhibit mild morphological signs of dysfunction and respond poorly to TSH, suggesting that the genetic changes affect the ability of the gland to release thyroid hormones. However, the phenotype of the mutant mice also has features of hyperthyroidism, including decreased body weight, elevated heart rate, and a raised body temperature. Furthermore, TRalpha2-/- and TRalpha2+/- mice are obese and exhibit skeletal alterations, associated with a late-onset growth retardation. The results thus suggest that the overexpression of TRalpha1 and the concomitant decrease in TRalpha2 expression lead to a mixed hyper- and hypothyroid phenotype, dependent on the tissue studied. The phenotypes suggest that the balance of TRalpha1:TRalpha2 expressed from the TRalpha gene provides an additional level of tuning the control of growth and homeostasis in mammalian species.
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