scholarly journals Thyroid hormone alters the DNA binding properties of chicken thyroid hormone receptors α and β

1992 ◽  
Vol 20 (18) ◽  
pp. 4803-4810 ◽  
Author(s):  
Monika L. Andersson ◽  
Kristina Nordström ◽  
Stephen Demczuk ◽  
Matthias Harbers ◽  
Björn Vennström
Keyword(s):  
Thyroid Hormone ◽  
Dna Binding ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptors ◽  
Binding Properties ◽  
Dna Binding Properties

scholarly journals Interactions of Estrogen- and Thyroid Hormone Receptors on a Progesterone Receptor Estrogen Response Element (ERE) Sequence: a Comparison with the Vitellogenin A2 Consensus ERE

1997 ◽  
Vol 11 (11) ◽  
pp. 1581-1592 ◽  
Author(s):  
Roderick E. M. Scott ◽  
X. Sharon Wu-Peng ◽  
Paul M. Yen ◽  
William W. Chin ◽  
Donald W. Pfaff
Keyword(s):  
Thyroid Hormone ◽  
Dna Binding ◽  
Reproductive Behavior ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptors ◽  
Estrogen Response Element ◽  
Hormone Response ◽  
Response Element ◽  
Estrogen Response

Abstract The identification of hormone response elements in the promoter regions of hormonally regulated genes has revealed a striking similarity between the half-site of the estrogen-response element (ERE) and a consensus sequence constituting the thyroid hormone-response element. Because of the potential for thyroid hormone (T3) to affect estrogen (E)- and progesterone-dependent female reproductive behavior via EREs, we have begun to investigate the activity of an ERE identified in the progesterone receptor (PR) proximal promoter and its interactions with the estrogen receptor (ER) and thyroid hormone receptors (TR). In addition, we have compared ER and TR interactions on the PR ERE construct with that of the vitellogenin A2 (vit A2) consensus ERE. Electrophoretic mobility shift assays demonstrated that TR binds to the PR ERE as well as to the consensus ERE sequence in vitro. Further, these two EREs were differentially regulated by T3 in the presence of TR. T3 in the presence of TRα increased transcription from a PR ERE construct ∼5-fold and had no inhibitory effect on E induction. Similarly, T3 also activated a β-galactosidase reporter construct containing PR promoter sequences spanning −1400 to +700. In addition, the TR isoforms β1 and β2 also stimulated transcription from the PR ERE construct by 5- to 6-fold. A TRα mutant lacking the ability to bind AGGTCA sequences in vitro failed to activate transcription from the PR ERE construct, demonstrating dependence on DNA binding. In contrast to its actions on the PR ERE construct, TRα did not activate transcription from the vit A2 consensus ERE but rather attenuated E-mediated transcriptional activation. Attenuation from the vit A2 consensus ERE is not necessarily dependent on DNA binding as the TRα DNA binding mutant was still able to inhibit E-dependent transactivation. In contrast to TRα, the isoforms TRβ1 and TRβ2 failed to inhibit E-induced activation from the vit A2 consensus ERE. These results demonstrate that the PR ERE construct differs from the vit A2 consensus ERE in its ability to respond to TRs and that divergent pathways exist for activation and inhibition by TR. Since ERs, PRs, and TRs are all present in hypothalamic neurons, these findings may be significant for endocrine integration, which is important for reproductive behavior.

scholarly journals Thyroid hormone alters in vitro DNA binding of monomers and dimers of thyroid hormone receptors.

1992 ◽  
Vol 6 (7) ◽  
pp. 1142-1152
Author(s):  
R C Ribeiro ◽  
P J Kushner ◽  
J W Apriletti ◽  
B L West ◽  
J D Baxter
Keyword(s):  
Thyroid Hormone ◽  
Dna Binding ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptors

scholarly journals Thyroid hormone receptor can modulate retinoic acid-mediated axis formation in frog embryogenesis.

1993 ◽  
Vol 13 (12) ◽  
pp. 7540-7552 ◽  
Author(s):  
D E Banker ◽  
R N Eisenman
Keyword(s):  
Gene Expression ◽  
Retinoic Acid ◽  
Thyroid Hormone ◽  
Dna Binding ◽  
Hormone Receptor ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptor ◽  
Retinoic Acid Receptor ◽  
Thyroid Hormone Receptors ◽  
Axis Formation

Thyroid hormone receptor acts as a hormone-dependent transcriptional transactivator and as a transcriptional repressor in the absence of thyroid hormone. Specifically, thyroid hormone receptor can repress retinoic acid-induced gene expression through interactions with retinoic acid receptor. (Retinoic acid is a potent teratogen in the frog Xenopus laevis, acting at early embryonic stages to interfere with the formation of anterior structures. Endogenous retinoic acid is thought to act in normal anterior-posterior axis formation.) We have previously shown that thyroid hormone receptor RNA (alpha isotype) is expressed and polysome-associated during Xenopus embryogenesis preceding thyroid gland maturation and endogenous thyroid hormone production (D. E. Banker, J. Bigler, and R. N. Eisenman, Mol. Cell. Biol. 11:5079-5089, 1991). To determine whether thyroid hormone receptor might influence the effects of retinoic acid in early frog development, we have examined the results of ectopic thyroid hormone receptor expression on retinoic acid teratogenesis. We demonstrate that microinjections of full-length thyroid hormone receptor RNA protect injected embryos from retinoic acid teratogenesis. DNA binding is apparently essential to this protective function, as truncated thyroid hormone receptors, lacking DNA-binding domains but including hormone-binding and dimerization domains, do not protect from retinoic acid. We have shown that microinjections of these dominant-interfering thyroid hormone receptors, as well as anti-thyroid hormone receptor antibodies, increase retinoic acid teratogenesis in injected embryos, presumably by inactivating endogenous thyroid hormone receptor. This finding suggests that endogenous thyroid hormone receptors may act to limit retinoic acid sensitivity. On the other hand, after thyroid hormone treatment, ectopic thyroid hormone receptor mediates teratogenesis that is indistinguishable from the dorsoanterior deficiencies produced in retinoic acid teratogenesis. The previously characterized retinoic acid-responsive gene, Xhox.lab2, can be induced by thyroid hormone in embryos ectopically expressing thyroid hormone receptor and is less responsive to retinoic acid in such embryos. The fact that both thyroid hormone and retinoic acid can affect overlapping gene expression pathways to produce abnormal embryonic axes and can regulate the same early-expressed gene suggests a model in which thyroid hormone receptor blocks retinoic acid receptor-mediated teratogenesis by directly repressing retinoic acid-responsive genes.

Thyroid hormone receptor can modulate retinoic acid-mediated axis formation in frog embryogenesis

1993 ◽  
Vol 13 (12) ◽  
pp. 7540-7552
Author(s):  
D E Banker ◽  
R N Eisenman
Keyword(s):  
Gene Expression ◽  
Retinoic Acid ◽  
Thyroid Hormone ◽  
Dna Binding ◽  
Hormone Receptor ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptor ◽  
Retinoic Acid Receptor ◽  
Thyroid Hormone Receptors ◽  
Axis Formation

Thyroid hormone receptor acts as a hormone-dependent transcriptional transactivator and as a transcriptional repressor in the absence of thyroid hormone. Specifically, thyroid hormone receptor can repress retinoic acid-induced gene expression through interactions with retinoic acid receptor. (Retinoic acid is a potent teratogen in the frog Xenopus laevis, acting at early embryonic stages to interfere with the formation of anterior structures. Endogenous retinoic acid is thought to act in normal anterior-posterior axis formation.) We have previously shown that thyroid hormone receptor RNA (alpha isotype) is expressed and polysome-associated during Xenopus embryogenesis preceding thyroid gland maturation and endogenous thyroid hormone production (D. E. Banker, J. Bigler, and R. N. Eisenman, Mol. Cell. Biol. 11:5079-5089, 1991). To determine whether thyroid hormone receptor might influence the effects of retinoic acid in early frog development, we have examined the results of ectopic thyroid hormone receptor expression on retinoic acid teratogenesis. We demonstrate that microinjections of full-length thyroid hormone receptor RNA protect injected embryos from retinoic acid teratogenesis. DNA binding is apparently essential to this protective function, as truncated thyroid hormone receptors, lacking DNA-binding domains but including hormone-binding and dimerization domains, do not protect from retinoic acid. We have shown that microinjections of these dominant-interfering thyroid hormone receptors, as well as anti-thyroid hormone receptor antibodies, increase retinoic acid teratogenesis in injected embryos, presumably by inactivating endogenous thyroid hormone receptor. This finding suggests that endogenous thyroid hormone receptors may act to limit retinoic acid sensitivity. On the other hand, after thyroid hormone treatment, ectopic thyroid hormone receptor mediates teratogenesis that is indistinguishable from the dorsoanterior deficiencies produced in retinoic acid teratogenesis. The previously characterized retinoic acid-responsive gene, Xhox.lab2, can be induced by thyroid hormone in embryos ectopically expressing thyroid hormone receptor and is less responsive to retinoic acid in such embryos. The fact that both thyroid hormone and retinoic acid can affect overlapping gene expression pathways to produce abnormal embryonic axes and can regulate the same early-expressed gene suggests a model in which thyroid hormone receptor blocks retinoic acid receptor-mediated teratogenesis by directly repressing retinoic acid-responsive genes.

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