scholarly journals Thyroid hormone receptors are required for the melatonin‐dependent control of Rfrp gene expression in mice

2020 ◽  
Vol 34 (9) ◽  
pp. 12072-12082
Author(s):  
Clarisse Quignon ◽  
Matthew Beymer ◽  
Karine Gauthier ◽  
François Gauer ◽  
Valérie Simonneaux
1991 ◽  
Vol 11 (10) ◽  
pp. 5079-5089 ◽  
Author(s):  
D E Banker ◽  
J Bigler ◽  
R N Eisenman

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.


2020 ◽  
Vol 244 (1) ◽  
pp. 83-94 ◽  
Author(s):  
Ángela Sánchez ◽  
Constanza Contreras-Jurado ◽  
Diego Rodríguez ◽  
Javier Regadera ◽  
Susana Alemany ◽  
...  

Hypothyroidism is often associated with anemia and immunological disorders. Similar defects are found in patients and in mice with a mutated dominant-negative thyroid hormone receptor α (TRα) and in knockout mice devoid of this receptor, suggesting that this isoform is responsible for the effects of the thyroid hormones in hematopoiesis. However, the hematological phenotype of mice lacking also TRβ has not yet been examined. We show here that TRα1/TRβ-knockout female mice, lacking all known thyroid hormone receptors with capacity to bind thyroid hormones, do not have overt anemia and in contrast with hypothyroid mice do not present reduced Gata1 or Hif1 gene expression. Similar to that found in hypothyroidism or TRα deficiency during the juvenile period, the B-cell population is reduced in the spleen and bone marrow of ageing TRα1/TRβ-knockout mice, suggesting that TRβ does not play a major role in B-cell development. However, splenic hypotrophy is more marked in hypothyroid mice than in TRα1/TRβ-knockout mice and the splenic population of T-lymphocytes is not significantly impaired in these mice in contrast with the reduction found in hypothyroidism. Our results show that the overall hematopoietic phenotype of the TRα1/TRβ-knockout mice is milder than that found in the absence of hormone. Although other mechanism/s cannot be ruled out, our results suggest that the unoccupied TRs could have a negative effect on hematopoiesis, likely secondary to repression of hematopoietic gene expression.


1991 ◽  
Vol 11 (10) ◽  
pp. 5079-5089
Author(s):  
D E Banker ◽  
J Bigler ◽  
R N Eisenman

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.


1989 ◽  
Vol 15 (4) ◽  
pp. 495-545 ◽  
Author(s):  
Herbert H. Samuels ◽  
Juan Casanova ◽  
Richard P. Copp ◽  
Laura Janocko ◽  
Bruce M. Raaka ◽  
...  

2004 ◽  
Vol 33 (2) ◽  
pp. 445-458 ◽  
Author(s):  
Kwang-Huei Lin ◽  
Chia-yu Chen ◽  
Shen-Liang Chen ◽  
Chun-Che Yen ◽  
Ya-Hui Huang ◽  
...  

Thyroid hormones regulate growth, development, differentiation, and metabolic processes by interacting with and activating thyroid hormone receptors and associated pathways. We investigated the triiodothyronine (T3) modulation of gene expression, in human hepatocellular carcinoma cell lines, via a PCR-based cDNA subtraction method. Here we present further data on one of the T3-upregulated genes, fibronectin (FN). We demonstrate that the induction of FN protein expression by T3 in TRα1 and TRβ1 over-expressing cells was time and dose-dependent at the mRNA and protein levels. Blockade of protein synthesis by cycloheximide almost completely inhibited the concomitant induction of FN mRNA by T3, indicating that T3 indirectly regulates FN. Furthermore, nuclear-run on and FN promoter assay clearly can specifically increase the number of FN transcriptional demonstrated that the presence of T3 initiations. In addition, we further confirmed that the up-regulation of FN by T3 was mediated, at least in part, by transforming growth factor-β (TGF-β), because the induction of FN was blocked in a dose-dependent manner by the addition of TGF-β neutralizing antibody. In an effort to elucidate the we demonstrated the involvement of the signaling pathways involved in the activation of FN by T3, mitogen activated protein kinase/c-Jun N-terminal kinase/p38 MAPK (MAPK/JNK/p38) pathway. Although T3 induces the expression of TGF-β, neither wild-type nor dominant-negative Smad3 or Smad4 over-expression affected the activation of FN by T3. Thus, we demonstrate that T3 regulates FN gene expression indirectly at the transcriptional level, with the participation of the MAPK/JNK/p38 pathway and the TGF-β signaling pathway but independent of Smad3/4.


Life Sciences ◽  
1999 ◽  
Vol 64 (20) ◽  
pp. 1793-1802 ◽  
Author(s):  
Chang-Gyu Hahn ◽  
Aaron C. Pawlyk ◽  
Peter C. Whybrow ◽  
Lazlo Gyulai ◽  
Shanaz M. Tejani-Butt

1993 ◽  
Vol 13 (12) ◽  
pp. 7540-7552 ◽  
Author(s):  
D E Banker ◽  
R N Eisenman

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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