scholarly journals Characterization of a Third Human Thyroid Hormone Receptor Coexpressed with Other Thyroid Hormone Receptors in Several Tissues

1988 ◽  
Vol 2 (11) ◽  
pp. 1087-1092 ◽  
Author(s):  
Akira Nakai ◽  
Akihiro Sakurai ◽  
Graeme I. Bell ◽  
Leslie J. DeGroot
Keyword(s):  
Thyroid Hormone ◽  
Hormone Receptor ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptor ◽  
Thyroid Hormone Receptors ◽  
Human Thyroid

scholarly journals The thyroid hormone receptor gene (c-erbA alpha) is expressed in advance of thyroid gland maturation during the early embryonic development of Xenopus laevis.

1991 ◽  
Vol 11 (10) ◽  
pp. 5079-5089 ◽  
Author(s):  
D E Banker ◽  
J Bigler ◽  
R N Eisenman
Keyword(s):  
Gene Expression ◽  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Xenopus Laevis ◽  
Hormone Receptor ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptor ◽  
Thyroid Hormone Receptors ◽  
Stages Of Development ◽  
Xenopus Development

The c-erbA proto-oncogene encodes the thyroid hormone receptor, a ligand-dependent transcription factor which plays an important role in vertebrate growth and development. To define the role of the thyroid hormone receptor in developmental processes, we have begun studying c-erbA gene expression during the ontogeny of Xenopus laevis, an organism in which thyroid hormone has well-documented effects on morphogenesis. Using polymerase chain reactions (PCR) as a sensitive assay of specific gene expression, we found that polyadenylated erbA alpha RNA is present in Xenopus cells at early developmental stages, including the fertilized egg, blastula, gastrula, and neurula. By performing erbA alpha-specific PCR on reverse-transcribed RNAs from high-density sucrose gradient fractions prepared from early-stage embryos, we have demonstrated that these erbA transcripts are recruited to polysomes. Therefore, erbA is expressed in Xenopus development prior to the appearance of the thyroid gland anlage in tailbud-stage embryos. This implies that erbA alpha/thyroid hormone receptors may play ligand-independent roles during the early development of X. laevis. Quantitative PCR revealed a greater than 25-fold range in the steady-state levels of polyadenylated erbA alpha RNA across early stages of development, as expressed relative to equimolar amounts of total embryonic RNA. Substantial increases in the levels of erbA alpha RNA were noted at stages well after the onset of zygotic transcription at the mid-blastula transition, with accumulation of erbA alpha transcripts reaching a relative maximum in advance of metamorphosis. We also show that erbA alpha RNAs are expressed unequally across Xenopus neural tube embryos. This differential expression continues through later stages of development, including metamorphosis. This finding suggests that erbA alpha/thyroid hormone receptors may play roles in tissue-specific processes across all of Xenopus development.

scholarly journals Differences between the silencing-related properties of the extreme carboxyl-terminal regions of thyroid hormone receptors alpha 1 and beta 1

2000 ◽  
Vol 167 (2) ◽  
pp. 219-227 ◽  
Author(s):  
K Nishiyama ◽  
A Matsushita ◽  
H Natsume ◽  
T Mikami ◽  
R Genma ◽  
...  
Keyword(s):  
Amino Acid ◽  
Thyroid Hormone ◽  
Hormone Receptors ◽  
Target Genes ◽  
Thyroid Hormone Receptor ◽  
Thyroid Hormone Receptors ◽  
Human Thyroid ◽  
Wild Type ◽  
Amino Acid Deletion ◽  
The Difference

Human thyroid hormone receptor (TR) is encoded by two distinct genes, TR alpha and TR beta. TR heterodimerizes with retinoid X receptor (RXR) and binds efficiently to the thyroid hormone (T(3)) response element (TRE) of target genes. In the absence of T(3), unliganded TR suppresses the basal promoter activity of positively regulated genes (silencing). Silencing mediator for retinoid and thyroid hormone receptors (SMRT) and nuclear receptor co-repressor (N-CoR) interact with unliganded TR and function as corepressor proteins. Previously, we found beta F451X with carboxyl (C)-terminal 11-amino acid deletion had stronger silencing potency than wild-type TR beta 1 and beta E449X with C-terminal 13-amino acid deletion on a subset of TREs. In the present study, to assess the isoform-specific effects of the C-terminal truncations on TR silencing, we constructed two mutant TR alpha 1s (alpha F397X and alpha E395X) with the same respective C-terminal truncations as beta F451X and beta E449X and analysed their silencing activities. Unlike beta F451X and beta E449X, alpha F397X and alpha E395X showed similarly stronger silencing potency than wild-type TR alpha 1. We further studied the abilities of wild-type and the mutant TR beta 1s and alpha 1s on RXR and co-repressor binding by a two-hybrid interference assay. beta F451X had significantly stronger abilities to bind to RXR and SMRT than did wild-type TR beta 1 and beta E449X. In contrast, wild-type TR alpha 1, alpha F397X and alpha E395X showed similar abilities to bind to RXR and SMRT. beta E449X and alpha E395X, which have identical C-terminal truncation, showed less ability to bind to N-CoR than did wild-type TR beta 1 and beta F451X and wild-type TR alpha 1 and alpha F397X respectively. These results indicate that an identical C-terminal truncation gives rise to different effects on TR beta 1 and alpha1 with respect to silencing potency, RXR binding and SMRT binding. The difference in the silencing potency among wild-type TR beta 1, beta F451X and beta E449X correlated well with the difference in the ability to bind co-repressor SMRT.

The thyroid hormone receptor gene (c-erbA alpha) is expressed in advance of thyroid gland maturation during the early embryonic development of Xenopus laevis

1991 ◽  
Vol 11 (10) ◽  
pp. 5079-5089
Author(s):  
D E Banker ◽  
J Bigler ◽  
R N Eisenman
Keyword(s):  
Gene Expression ◽  
Thyroid Hormone ◽  
Thyroid Gland ◽  
Xenopus Laevis ◽  
Hormone Receptor ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptor ◽  
Thyroid Hormone Receptors ◽  
Stages Of Development ◽  
Xenopus Development

The c-erbA proto-oncogene encodes the thyroid hormone receptor, a ligand-dependent transcription factor which plays an important role in vertebrate growth and development. To define the role of the thyroid hormone receptor in developmental processes, we have begun studying c-erbA gene expression during the ontogeny of Xenopus laevis, an organism in which thyroid hormone has well-documented effects on morphogenesis. Using polymerase chain reactions (PCR) as a sensitive assay of specific gene expression, we found that polyadenylated erbA alpha RNA is present in Xenopus cells at early developmental stages, including the fertilized egg, blastula, gastrula, and neurula. By performing erbA alpha-specific PCR on reverse-transcribed RNAs from high-density sucrose gradient fractions prepared from early-stage embryos, we have demonstrated that these erbA transcripts are recruited to polysomes. Therefore, erbA is expressed in Xenopus development prior to the appearance of the thyroid gland anlage in tailbud-stage embryos. This implies that erbA alpha/thyroid hormone receptors may play ligand-independent roles during the early development of X. laevis. Quantitative PCR revealed a greater than 25-fold range in the steady-state levels of polyadenylated erbA alpha RNA across early stages of development, as expressed relative to equimolar amounts of total embryonic RNA. Substantial increases in the levels of erbA alpha RNA were noted at stages well after the onset of zygotic transcription at the mid-blastula transition, with accumulation of erbA alpha transcripts reaching a relative maximum in advance of metamorphosis. We also show that erbA alpha RNAs are expressed unequally across Xenopus neural tube embryos. This differential expression continues through later stages of development, including metamorphosis. This finding suggests that erbA alpha/thyroid hormone receptors may play roles in tissue-specific processes across all of Xenopus development.

scholarly journals Nontranscriptional modulation of intracellular Ca2+ signaling by ligand stimulated thyroid hormone receptor

2004 ◽  
Vol 167 (5) ◽  
pp. 915-924 ◽  
Author(s):  
Nuttawut Saelim ◽  
Linu M. John ◽  
Jun Wu ◽  
Jeong Soon Park ◽  
Yidong Bai ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Hormone Receptor ◽  
Transcriptional Activity ◽  
Hormone Receptors ◽  
Thyroid Hormone Receptor ◽  
Wave Activity ◽  
Ruthenium Red ◽  
Thyroid Hormone Receptors ◽  
Localization Signal ◽  
Receptor Beta

Thyroid hormone 3,5,3′-tri-iodothyronine (T3) binds and activates thyroid hormone receptors (TRs). Here, we present evidence for a nontranscriptional regulation of Ca2+ signaling by T3-bound TRs. Treatment of Xenopus thyroid hormone receptor beta subtype A1 (xTRβA1) expressing oocytes with T3 for 10 min increased inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ wave periodicity. Coexpression of TRβA1 with retinoid X receptor did not enhance regulation. Deletion of the DNA binding domain and the nuclear localization signal of the TRβA1 eliminated transcriptional activity but did not affect the ability to regulate Ca2+ signaling. T3-bound TRβA1 regulation of Ca2+ signaling could be inhibited by ruthenium red treatment, suggesting that mitochondrial Ca2+ uptake was required for the mechanism of action. Both xTRβA1 and the homologous shortened form of rat TRα1 (rTRαΔF1) localized to the mitochondria and increased O2 consumption, whereas the full-length rat TRα1 did neither. Furthermore, only T3-bound xTRβA1 and rTRαΔF1 affected Ca2+ wave activity. We conclude that T3-bound mitochondrial targeted TRs acutely modulate IP3-mediated Ca2+ signaling by increasing mitochondrial metabolism independently of transcriptional activity.

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