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Jiao F, Qiao K, Jiang Y, Li S, Zhao J, Gui W. Integrated thyroid endocrine disrupting effect on zebrafish (Danio rario) larvae via simultaneously repressing type II iodothyronine deiodinase and activating thyroid receptor-mediated signaling following waterborne exposure to trace azocyclotin. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 255:113328. [PMID: 31671316 DOI: 10.1016/j.envpol.2019.113328] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/26/2019] [Accepted: 09/29/2019] [Indexed: 06/10/2023]
Abstract
As a widely used organotin acaricide nowadays, azocyclotin (ACT) could induce thyroidal endocrine disruption in fishes and amphibians, but its dominant disrupting mode remains unknown. In this study, zebrafish were firstly exposed to ACT (0.18-0.36 ng/mL) from 2 hpf (hours post fertilization) to 30 dpf (days post fertilization), and a series of developmental toxicological endpoints and thyroid hormones were measured. Result showed that no developmental toxicity to zebrafish was found in 0.18 and 0.24 ng/mL groups except decreased body weight (30 dpf, 0.24 ng/mL). However, exposed to 0.36 ng/mL ACT led to reductions in heartbeat (48 hpf), hatching rate (72 hpf) and bodyweight (30 dpf). General tendencies of decreases in free T3 but increases in free T4 and reductions in ratio of free T3/T4 were also found, inferring that type II deiodinase (Dio2) was repressed. This inference was confirmed by Western analysis that Dio2 expression reduced by 42.7% after 0.36 ng/mL ACT treatment. Moreover, RNA-Seq analysis implied that exposed to 0.36 ng/mL ACT altered the genome-wide gene expression profiles of zebrafish. Totally 5660 genes (involving 3154 down-regulated and 2596 up-regulated genes) were differentially expressed, and 13 deferentially expressed genes including down-regulated dio2 were significantly enriched in thyroid hormone signaling pathway. Subsequently, an in vitro thyroid receptor-reporter gene assay using GH3 cells was performed to further explore the potential disrupting mechanism. Result showed that luciferase activity slightly increased after exposure to ACT alone or ACT combined with low level T3, but was suppressed when combined with high level T3. It indicted there probably existed a competitive relationship in some extent between ACT and T3 in vivo. Overall, the present study provided preliminary evidences that long-term exposure to trace ACT repressed Dio2 expression, declined T3 and then activated thyroid receptor-mediated signaling, thereby leading to integrated thyroid endocrine disruption in zebrafish larvae.
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Affiliation(s)
- Fang Jiao
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, PR China
| | - Kun Qiao
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, PR China
| | - Yao Jiang
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, PR China
| | - Shuying Li
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, PR China
| | - Jinghao Zhao
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, PR China
| | - Wenjun Gui
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, 310058, PR China.
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2
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Bargi-Souza P, Goulart-Silva F, Nunes MT. Novel aspects of T 3 actions on GH and TSH synthesis and secretion: physiological implications. J Mol Endocrinol 2017; 59:R167-R178. [PMID: 28951438 DOI: 10.1530/jme-17-0068] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 09/26/2017] [Indexed: 12/27/2022]
Abstract
Thyroid hormones (THs) classically regulate the gene expression by transcriptional mechanisms. In pituitary, the encoding genes for growth hormone (GH) and thyroid-stimulating hormone (TSH) are examples of genes regulated by triiodothyronine (T3) in a positive and negative way, respectively. Recent studies have shown a rapid adjustment of GH and TSH synthesis/secretion induced by T3 posttranscriptional actions. In somatotrophs, T3 promotes an increase in Gh mRNA content, poly(A) tail length and binding to the ribosome, associated with a rearrangement of actin cytoskeleton. In thyrotrophs, T3 reduces Tshb mRNA content, poly(A) tail length and its association with the ribosome. In parallel, it promotes a redistribution of TSH secretory granules to more distal regions of the cell periphery, indicating a rapid effect of T3 inhibition of TSH secretion. T3 was shown to affect the content of tubulin and the polymerization of actin and tubulin cytoskeletons in the whole anterior pituitary gland, and to increase intracellular alpha (CGA) content. This review summarizes genomic and non-genomic/posttranscriptional actions of TH on the regulation of several steps of GH and TSH synthesis and secretion. These distinct mechanisms induced by T3 can occur simultaneously, even though non-genomic effects are promptly elicited and precede the genomic actions, coexisting in a functional network within the cells.
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Affiliation(s)
| | | | - M T Nunes
- Department of Physiology and Biophysics of the Institute of Biomedical SciencesUniversity of São Paulo, São Paulo, SP, Brazil
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3
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Silvestri E, Lombardi A, de Lange P, Glinni D, Senese R, Cioffi F, Lanni A, Goglia F, Moreno M. Studies of complex biological systems with applications to molecular medicine: the need to integrate transcriptomic and proteomic approaches. J Biomed Biotechnol 2010; 2011:810242. [PMID: 20981256 PMCID: PMC2963870 DOI: 10.1155/2011/810242] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 09/08/2010] [Indexed: 02/07/2023] Open
Abstract
Omics approaches to the study of complex biological systems with potential applications to molecular medicine are attracting great interest in clinical as well as in basic biological research. Genomics, transcriptomics and proteomics are characterized by the lack of an a priori definition of scope, and this gives sufficient leeway for investigators (a) to discern all at once a globally altered pattern of gene/protein expression and (b) to examine the complex interactions that regulate entire biological processes. Two popular platforms in "omics" are DNA microarrays, which measure messenger RNA transcript levels, and proteomic analyses, which identify and quantify proteins. Because of their intrinsic strengths and weaknesses, no single approach can fully unravel the complexities of fundamental biological events. However, an appropriate combination of different tools could lead to integrative analyses that would furnish new insights not accessible through one-dimensional datasets. In this review, we will outline some of the challenges associated with integrative analyses relating to the changes in metabolic pathways that occur in complex pathophysiological conditions (viz. ageing and altered thyroid state) in relevant metabolically active tissues. In addition, we discuss several new applications of proteomic analysis to the investigation of mitochondrial activity.
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Affiliation(s)
- Elena Silvestri
- Dipartimento di Scienze Biologiche ed Ambientali, Università degli Studi del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy
| | - Assunta Lombardi
- Dipartimento delle Scienze Biologiche, Sezione Fisiologia, Università degli Studi di Napoli “Federico II”, Via Mezzocannone 8, 80134 Napoli, Italy
| | - Pieter de Lange
- Dipartimento di Scienze della Vita, Seconda Università di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
| | - Daniela Glinni
- Dipartimento di Scienze Biologiche ed Ambientali, Università degli Studi del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy
| | - Rosalba Senese
- Dipartimento di Scienze della Vita, Seconda Università di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
| | - Federica Cioffi
- Dipartimento di Scienze della Vita, Seconda Università di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
| | - Antonia Lanni
- Dipartimento di Scienze della Vita, Seconda Università di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
| | - Fernando Goglia
- Dipartimento di Scienze Biologiche ed Ambientali, Università degli Studi del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy
| | - Maria Moreno
- Dipartimento di Scienze Biologiche ed Ambientali, Università degli Studi del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy
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4
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Zoeller RT, Tan SW, Tyl RW. General background on the hypothalamic-pituitary-thyroid (HPT) axis. Crit Rev Toxicol 2007; 37:11-53. [PMID: 17364704 DOI: 10.1080/10408440601123446] [Citation(s) in RCA: 262] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This article reviews the thyroid system, mainly from a mammalian standpoint. However, the thyroid system is highly conserved among vertebrate species, so the general information on thyroid hormone production and feedback through the hypothalamic-pituitary-thyroid (HPT) axis should be considered for all vertebrates, while species-specific differences are highlighted in the individual articles. This background article begins by outlining the HPT axis with its components and functions. For example, it describes the thyroid gland, its structure and development, how thyroid hormones are synthesized and regulated, the role of iodine in thyroid hormone synthesis, and finally how the thyroid hormones are released from the thyroid gland. It then progresses to detail areas within the thyroid system where disruption could occur or is already known to occur. It describes how thyroid hormone is transported in the serum and into the tissues on a cellular level, and how thyroid hormone is metabolized. There is an in-depth description of the alpha and beta thyroid hormone receptors and their functions, including how they are regulated, and what has been learned from the receptor knockout mouse models. The nongenomic actions of thyroid hormone are also described, such as in glucose uptake, mitochondrial effects, and its role in actin polymerization and vesicular recycling. The article discusses the concept of compensation within the HPT axis and how this fits into the paradigms that exist in thyroid toxicology/endocrinology. There is a section on thyroid hormone and its role in mammalian development: specifically, how it affects brain development when there is disruption to the maternal, the fetal, the newborn (congenital), or the infant thyroid system. Thyroid function during pregnancy is critical to normal development of the fetus, and several spontaneous mutant mouse lines are described that provide research tools to understand the mechanisms of thyroid hormone during mammalian brain development. Overall this article provides a basic understanding of the thyroid system and its components. The complexity of the thyroid system is clearly demonstrated, as are new areas of research on thyroid hormone physiology and thyroid hormone action developing within the field of thyroid endocrinology. This review provides the background necessary to review the current assays and endpoints described in the following articles for rodents, fishes, amphibians, and birds.
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Affiliation(s)
- R Thomas Zoeller
- Biology Department, Morrill Science Center, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, USA.
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Shen X, Li QL, Brent GA, Friedman TC. Regulation of regional expression in rat brain PC2 by thyroid hormone/characterization of novel negative thyroid hormone response elements in the PC2 promoter. Am J Physiol Endocrinol Metab 2005; 288:E236-45. [PMID: 15585599 DOI: 10.1152/ajpendo.00144.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The prohormone convertases (PCs) PC1 and PC2 are involved in the tissue-specific endoproteolytic processing of neuropeptide precursors within the secretory pathway. We previously showed that changes in thyroid status altered pituitary PC2 mRNA and that this regulation was due to triiodothyronine-dependent interaction of the thyroid hormone receptor (TR) with negative thyroid hormone response elements (nTREs) contained in a large proximal region of the human PC2 promoter. In the current study, we examined the in vivo regulation of brain PC2 mRNA by thyroid status and found that 6-n-propyl-2-thiouracil-induced hypothyroidism stimulated, whereas thyroxine-induced hyperthyroidism suppressed, PC2 mRNA levels in the rat hypothalamus and cerebral cortex. To address the mechanism of T3 regulation of the PC2 gene, we used human PC2 (hPC2) promoter constructs transiently transfected into GH3 cells and found that triiodothyronine negatively and 9-cis-retinoic acid positively regulated hPC2 promoter activity. EMSAs, using purified TRalpha1 and retinoid X receptor-beta (RXRbeta) proteins demonstrated that TRalpha bound the distal putative nTRE-containing oligonucleotide in the PC2 promoter, and RXR bound to both nTRE-containing oligonucleotides. EMSAs with oligonucleotides containing deletion mutations of the nTREs demonstrated that the binding to TR and RXR separately is reduced, but specific binding to TR and RXR together persists even with deletion of each putative nTRE. We conclude that there are two novel TRE-like sequences in the hPC2 promoter and that these regions act in concert in a unique manner to facilitate the effects of thyroid hormone and 9-cis-retinoic acid on PC2.
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Affiliation(s)
- Xiaoxiong Shen
- Division of Endocrinology, Department of Medicine, Charles R. Drew University of Medicine & Sciences, Los Angeles, CA 90059, USA
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Scheller K, Seibel P, Sekeris CE. Glucocorticoid and thyroid hormone receptors in mitochondria of animal cells. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 222:1-61. [PMID: 12503846 DOI: 10.1016/s0074-7696(02)22011-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This article concerns the localization of glucocorticoid and thyroid hormone receptors in mitochondria of animal cells. The receptors are discussed in terms of their potential role in the regulation of mitochondrial transcription and energy production by the oxidative phosphorylation pathway, realized both by nuclear-encoded and mitochondrially encoded enzymes. A brief survey of the role of glucocorticoid and thyroid hormones on energy metabolism is presented, followed by a description of the molecular mode of action of these hormones and of the central role of the receptors in regulation of transcription. Subsequently, the structure and characteristics of glucocorticoid and thyroid hormone receptors are described, followed by a section on the effects of glucocorticoid and thyroid hormones on the transcription of mitochondrial and nuclear genes encoding subunits of OXPHOS and by an introduction to the mitochondrial genome and its transcription. A comprehensive description of the data demonstrates the localization of glucocorticoid and thyroid hormone receptors in mitochondria as well as the detection of potential hormone response elements that bind to these receptors. This leads to the conclusion that the receptors potentially play a role in the regulation of transcription of mitochondrial genes. The in organello mitochondrial system, which is capable of sustaining transcription in the absence of nuclear participation, is presented, responding to T3 with increased transcription rates, and the central role of a thyroid receptor isoform in the transcription effect is emphasized. Lastly, possible ways of coordinating nuclear and mitochondrial gene transcription in response to glucocorticoid and thyroid hormones are discussed, the hormones acting directly on the genes of the two compartments by way of common hormone response elements and indirectly on mitochondrial genes by stimulation of nuclear-encoded transcription factors.
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Affiliation(s)
- Klaus Scheller
- Department of Cell and Developmental Biology, Biocenter of the University, D-97074 Würzburg, Germany
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7
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Abstract
Both in vivo and in primary rat hepatocyte culture, carbohydrate and triiodothyronine (T(3)) rapidly induce transcription of the rat S14 gene. To determine if regulation of this gene by T(3) is similar in human liver cells, we transfected the S14 upstream region into HepG2 cells. We chose this cell line because many others have used this cell line to study the effect of thyroid hormone on hepatic gene expression. We found that changing media glucose concentration did not affect S14 transcription. Furthermore, addition of T(3) to HepG2 cells caused a marked reduction of rat S14 transcription. This paradoxical reduction was dependent on cotransfection of the T(3) receptor. We obtained similar results in the other human hepatoma cell lines, HuH-7 and Hep3B. The paradoxical response was not limited to human cells. We found a similar response in the nonmalignant permanent mouse liver cell line, AML-12. This paradoxical response was specific to the S14 gene because transfection of all the cell lines with a CAT or luciferase reporter driven by a mouse mammary tumor virus promoter containing 1 or 4 copies of a palindromic thyroid hormone response element (TRE) showed marked induction by T(3). Our results show that T(3) abnormally regulates the S14 gene in proliferating liver cell lines of diverse origins. This paradoxical regulation by T(3) is caused by an interaction between T(3) and the thyroid hormone receptor. The factors that lead to this paradoxical response are not active in primary hepatocytes and normal intact liver.
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Affiliation(s)
- Yasuhiro Ota
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, University of Minnesota, Minneapolis 55455, USA
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8
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Abstract
Nuclear receptors (NRs) comprise a family of 49 members that share a common structural organization and act as ligand-inducible transcription factors with major (patho)physiological impact. For some NRs (“orphan receptors”), cognate ligands have not yet been identified or may not exist. The principles of DNA recognition and ligand binding are well understood from both biochemical and crystal structure analyses. The 3D structures of several DNA-binding domains (DBDs),in complexes with a variety of cognate response elements, and multiple ligand-binding domains (LBDs), in the absence (apoLBD)and presence (holoLBD) of agonist, have been established and reveal canonical structural organization. Agonist binding induces a structural transition in the LBD whose most striking feature is the relocation of helix H12, which is required for establishing a coactivator complex, through interaction with members of the p160 family (SRC1, TIF2, AIB1) and/or the TRAP/DRIP complex. The p160-dependent coactivator complex is a multiprotein complex that comprises histone acetyltransferases (HATs), such as CBP,methyltransferases, such as CARM1, and other enzymes (SUMO ligase,etc.). The agonist-dependent recruitment of the HAT complex results in chromatin modification in the environment of the target gene promoters, which is requisite to, or may in some cases be sufficient for, transcription activation. In the absence of ligands, or in the presence of some antagonists, certain NRs are bound to distinct multiprotein complexes through the interaction with corepressors, such as NCoR and SMRT. Corepressor complexes comprise histone deacetylases (HDACs) that have the capacity to condense chromatin over target gene promoters. Ligands have been designed that selectively modulate the interaction between NRs and their coregulators. Both HATs and HDACs can also modify the acetylation status of nonhistone proteins, but the significance in the context of NR signaling is unclear. NRs communicate with other intracellular signaling pathways on a mutual basis, and their functionality may be altered, positively or negatively, by post-translational modification. The majority of NRs act as retinoid X receptor (RXR) heterodimers in which RXR cannot a priori respond autonomously to its cognate ligand to activate target gene transcription. This RXR subordination allows signaling pathway identity for the RXR partner. The corresponding mechanism is understood and reveals cell and NR selectivity, indicating that RXR can, under certain conditions, act autonomously. NRs are regulators of cell life and death,and NR malfunction can be at the basis of both disease and therapy, as is impressively documented in the case of acute promyelocytic leukemia. Recently, several pathways have been uncovered that link NR action with cell proliferation and apoptosis.
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9
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Abstract
The prohormone convertases (PCs) PC1 and PC2 are key enzymes capable of processing a variety of prohormones to their bioactive forms. In this study, we demonstrated that 6-n-propyl-2-thiouracil (PTU)-induced hypothyroidism stimulated, whereas triido-L-thyronine (T(3))-induced hyperthyroidism suppressed, PC1 mRNA levels in the rat anterior pituitary. Using 5' deletions of the human PC1 (hPC1) promoter transiently transfected into GH3 (a somatotroph cell line) cells, we found that T(3) negatively regulated hPC1 promoter activity and that this regulation required the region from -82 to +19 bp relative to the transcription start site. Electrophoretic mobility shift assays (EMSAs) using purified thyroid hormone receptor-alpha1 (TR alpha 1) and retinoid X receptor-beta (RXRbeta) proteins and GH3 nuclear extracts demonstrated that the region from -10 to +19 bp of the hPC1 promoter bound TR alpha 1 as both a monomer and a homodimer and bound TR alpha 1/RXR beta as a heterodimer and multimer. EMSAs with oligonucleotides containing point mutations of the putative negative thyroid response elements (TREs) exhibited diminished homodimer and loss of multimer binding. We conclude that there are multiple novel TRE-like sequences in the hPC1 promoter located from -10 to +19 bp.
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MESH Headings
- Alitretinoin
- Animals
- Antineoplastic Agents/pharmacology
- Aspartic Acid Endopeptidases/genetics
- Aspartic Acid Endopeptidases/metabolism
- Cells, Cultured
- Gene Deletion
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Enzymologic/physiology
- Genes, Reporter
- Hypothyroidism/chemically induced
- Hypothyroidism/metabolism
- Luciferases/genetics
- Male
- Mutagenesis, Insertional/physiology
- Oligonucleotides/genetics
- Oligonucleotides/metabolism
- Peptide Fragments/metabolism
- Pituitary Gland, Anterior/metabolism
- Promoter Regions, Genetic/physiology
- Proprotein Convertases
- Protein Processing, Post-Translational/drug effects
- Protein Processing, Post-Translational/physiology
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Retinoic Acid/metabolism
- Retinoid X Receptors
- Transcription Factors/metabolism
- Tretinoin/pharmacology
- Triiodothyronine/metabolism
- Uracil/analogs & derivatives
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Affiliation(s)
- Q L Li
- Division of Endocrinology, Department of Medicine, Cedars-Sinai Research Institute--University of California at Los Angeles School of Medicine, Los Angeles, 90048, USA
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Li QL, Jansen E, Brent GA, Naqvi S, Wilber JF, Friedman TC. Interactions between the prohormone convertase 2 promoter and the thyroid hormone receptor. Endocrinology 2000; 141:3256-66. [PMID: 10965896 DOI: 10.1210/endo.141.9.7674] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The majority of prohormones are cleaved at paired basic residues to generate bioactive hormones by prohormone convertases (PCs). As PC1 and PC2, two neuroendocrine-specific PCs, appear to be the key enzymes capable of processing a variety of prohormones, alterations of PC2 and/or PC1 levels will probably have a profound effect on hormonal homeostasis. We investigated the regulation of PC2 messenger RNA (mRNA) by thyroid hormone using GH3 cells to demonstrate that T3 negatively regulated PC2 mRNA levels in a dose- and time-dependent fashion. Functional analysis of progressive 5'-deletions of the human (h) PC2 promoter luciferase constructs in GH3 cells demonstrated that the regulation probably occurs at the transcriptional level, and that putative negative thyroid hormone response elements were located within the region from -44 to + 137 bp relative to the transcriptional start site. Transient transfections in JEG-3 cells and COS-1 cells showed that the suppressive effect of T3 was equally mediated by the thyroid hormone receptor (TR) isoforms TRalpha1 and TRbeta1. Electrophoretic mobility shift assays using purified TRal and retinoid X receptor-beta protein as well as GH3 nuclear extracts showed that regions from +51 to +71 bp and from +118 to +137 bp of the hPC2 promoter bind to TRalpha1 as both a monomer and a homodimer and with TRalpha1/retinoid X receptor-beta as a heterodimer. Finally, the in vivo regulation of pituitary PC2 mRNA by thyroid status was demonstrated in rats. These results demonstrate that T3 negatively regulates PC2 expression at the transcriptional level and that functional negative thyroid hormone response elements exist in the hPC2 promoter. We postulate that the alterations of PC2 activity may mediate some of the pathophysiological consequences of hypo- or hyperthyroidism.
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Affiliation(s)
- Q L Li
- Department of Medicine, Cedars-Sinai Research Institute, University of California School of Medicine, Los Angeles 90048, USA
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11
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Casas F, Rochard P, Rodier A, Cassar-Malek I, Marchal-Victorion S, Wiesner RJ, Cabello G, Wrutniak C. A variant form of the nuclear triiodothyronine receptor c-ErbAalpha1 plays a direct role in regulation of mitochondrial RNA synthesis. Mol Cell Biol 1999; 19:7913-24. [PMID: 10567517 PMCID: PMC84876 DOI: 10.1128/mcb.19.12.7913] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In earlier research, we identified a 43-kDa c-ErbAalpha1 protein (p43) in the mitochondrial matrix of rat liver. In the present work, binding experiments indicate that p43 displays an affinity for triiodothyronine (T3) similar to that of the T3 nuclear receptor. Using in organello import experiments, we found that p43 is targeted to the organelle by an unusual process similar to that previously reported for MTF1, a yeast mitochondrial transcription factor. DNA-binding experiments demonstrated that p43 specifically binds to four mitochondrial DNA sequences with a high similarity to nuclear T3 response elements (mt-T3REs). Using in organello transcription experiments, we observed that p43 increases the levels of both precursor and mature mitochondrial transcripts and the ratio of mRNA to rRNA in a T3-dependent manner. These events lead to stimulation of mitochondrial protein synthesis. In transient-transfection assays with reporter genes driven by the mitochondrial D loop or two mt-T3REs located in the D loop, p43 stimulated reporter gene activity only in the presence of T3. All these effects were abolished by deletion of the DNA-binding domain of p43. Finally, p43 overexpression in QM7 cells increased the levels of mitochondrial mRNAs, thus indicating that the in organello influence of p43 was physiologically relevant. These data reveal a novel hormonal pathway functioning within the mitochondrion, involving a truncated form of a nuclear receptor acting as a potent mitochondrial T3-dependent transcription factor.
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Affiliation(s)
- F Casas
- Institut National de la Recherche Agronomique, Unité d'Endocrinologie Cellulaire, Laboratoire de Différenciation Cellulaire et Croissance, 34060 Montpellier Cedex 1, France
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12
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Satoh T, Monden T, Ishizuka T, Mitsuhashi T, Yamada M, Mori M. DNA binding and interaction with the nuclear receptor corepressor of thyroid hormone receptor are required for ligand-independent stimulation of the mouse preprothyrotropin-releasing hormone gene. Mol Cell Endocrinol 1999; 154:137-49. [PMID: 10509808 DOI: 10.1016/s0303-7207(99)00032-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A negative thyroid hormone response element (TRE) in the mouse preprothyrotropin-releasing hormone (TRH) gene was previously mapped within the proximal promoter element between -83 and +53 that contained a TRE half-site motif at -57 (-57TGACCT-51). In transfection experiments, the promoter activity is stimulated by unliganded thyroid hormone receptor (TR) and T3 reverses the basal promoter stimulation. In this study, we determined whether the direct binding of TR to the TRE half-site in the mouse TRH gene is required for the ligand-independent stimulation using a transient transfection assay into CV-1 cells and electrophoretic mobility shift assays (EMSA). In addition, the role of a corepressor protein for the ligand-independent stimulation was examined using a putative splicing variant of the nuclear receptor corepressor (N-CoRI). Point mutations introduced into the TRE half-site at -57 eliminated the binding of TR and the stimulatory effect of unliganded TR. Two mutant TRs lacking DNA-binding activity and two CoR box mutant TRs showed no stimulation in the wild-type TRH promoter. The cotransfected N-CoRI potentiated the ligand-independent stimulation by the wild-type TR, but did not compensate for the impaired function of the CoR box mutant TR. In EMSA, TR strongly bound as homodimers and weakly as heterodimers with retinoid X receptor (RXR) to the element containing the TRE half-site at -57. Binding of TR to the TRE half-site was essential to form homo- and heterodimers, and the RXR binding site appeared to be located downstream of the TRE half-site. In vitro translated N-CoRI preferentially bound TR homodimers over TR/RXR heterodimers. These results collectively suggest that the DNA-bound TR/corepressor complex might be directly involved in the ligand-independent stimulation of the mouse TRH gene promoter.
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Affiliation(s)
- T Satoh
- First Department of Internal Medicine, Gunma University School of Medicine, Maebashi, Japan.
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13
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Darling DS, Gaur NK, Zhu B. A zinc finger homeodomain transcription factor binds specific thyroid hormone response elements. Mol Cell Endocrinol 1998; 139:25-35. [PMID: 9705071 DOI: 10.1016/s0303-7207(98)00076-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Thyroid hormone receptors can act through response elements (TREs) having a wide variation of sequence. We screened for transcription factors that bind the rat (r) glycoprotein hormone alpha-subunit TRE (alpha-sub), and isolated a cDNA, termed zinc finger homeodomain enhancer-binding protein (Zfhep), which encodes two separate zinc finger domains (ZD1 and ZD2), and a region similar to homeodomains. DNA-binding assays show that ZD1 or ZD2 can bind the alpha-subunit, rat growth hormone, or thyrotropin beta (TSHbeta) gene TREs, but do not bind DR4 or palindromic (pal) TREs. Methylation interference footprinting demonstrates that Zfhep binds the alpha-sub overlapping the TR-binding site. Similarly, the ZD1 protein footprints over TR-binding halfsites of the rat growth hormone (rGH) and TSHbeta TREs. Hence, Zfhep binding is dependent on sequences within and outside the AGGTCA TR-binding halfsite. Interactions of non-receptor transcription factors (such as Zfhep) with certain TREs are important to modify gene-specific regulation by thyroid hormones.
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Affiliation(s)
- D S Darling
- Department of Biological and Biophysical Sciences, University of Louisville, School of Dentistry, Kentucky 40292, USA.
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14
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Langlois MF, Zanger K, Monden T, Safer JD, Hollenberg AN, Wondisford FE. A unique role of the beta-2 thyroid hormone receptor isoform in negative regulation by thyroid hormone. Mapping of a novel amino-terminal domain important for ligand-independent activation. J Biol Chem 1997; 272:24927-33. [PMID: 9312095 DOI: 10.1074/jbc.272.40.24927] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Negative regulation by thyroid hormone is mediated by nuclear thyroid hormone receptors (TRs) acting on thyroid hormone response elements (TREs). We examine here the role of human TR-beta2, a TR isoform with central nervous system-restricted expression, in the regulation of target genes whose expression are decreased by triiodothyronine (T3). Using transient transfection studies, we found that TR-beta2 achieved significantly greater ligand-independent activation on the thyrotropin-releasing hormone (TRH) and common glycoprotein alpha-subunit genes than either TR-beta1 or TR-alpha1. A chimeric TR-beta isoform containing the TR-beta2 amino terminus linked to the TR-alpha1 DNA- and ligand-binding domains functioned like the TR-beta2 isoform on these promoters, confirming that the amino terminus of TR-beta2 was both necessary and sufficient to mediate this effect. By constructing deletion mutants of the TR-beta2 amino terminus, we demonstrate that amino acids 89-116 mediate this function. This domain, important in ligand-independent activation on negative TREs, is discrete from a previously described activation domain in the amino-terminal portion of TR-beta2. We conclude that the central nervous system-restricted TR-beta2 isoform has a unique effect on negative regulation by T3 that can be mapped to amino acids 89-116 of the amino terminus of the human TR-beta2.
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Affiliation(s)
- M F Langlois
- Thyroid Unit, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
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15
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Sarapura VD, Wood WM, Bright TM, Ocran KW, Gordon DF, Ridgway EC. Reconstitution of triiodothyronine inhibition in non-triiodothyronine-responsive thyrotropic tumor cells using transfected thyroid hormone receptor isoforms. Thyroid 1997; 7:453-61. [PMID: 9226219 DOI: 10.1089/thy.1997.7.453] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The triiodothyronine (T3) inhibitory effect on the thyrotropin (TSH)beta- and alpha-subunit genes is believed to be mediated by binding of T3 to specific nuclear receptors that are present in various isoforms. alphaTSH cells, which are derived from a pure alpha-subunit secreting thyrotropic tumor, contain the same nuclear factors that are important for alpha-subunit gene expression in TSH-expressing T3-responsive thyrotropic cells (TtT97). However, as in the parent tumor, alpha-subunit expression in alphaTSH cells was not inhibited by T3, despite the presence of high-affinity nuclear T3 receptors (TRs) with a similar number of sites per cell as in TtT97. When transcripts coding for the different TR isoforms from the MGH101A tumor were analyzed by Northern blot, TR alpha1 was present, as well as the non-T3-binding variant alpha2, but transcripts encoding the opposite strand Rev-ErbAa were not detectable and neither TR beta1 nor TR beta2 mRNAs were detectable, whereas all these transcripts were detectable in TtT97 tumors. Similar findings were observed in alphaTSH cells, where TR beta1 transcripts were barely detectable in Northern blots and TR beta2 transcripts were detectable only by RT-PCR. The TR beta gene locus is present and unrearranged in the tumor genome. In transient transfection studies conducted in alphaTSH cells overexpression of either TR beta1, TR beta2, or TR alpha1 reconstituted T3-inhibition of the alpha-subunit promoter down to 40% to 50% of control. We conclude that the relative lack of TR beta gene expression correlates with unresponsiveness to T3. The alphaTSH cell line represents a unique model in which to dissect the mechanism of T3 inhibition.
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Affiliation(s)
- V D Sarapura
- University of Colorado Health Science Center, Denver 80262, USA
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16
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Waters KM, Miller CW, Ntambi JM. Localization of a negative thyroid hormone-response region in hepatic stearoyl-CoA desaturase gene 1. Biochem Biophys Res Commun 1997; 233:838-43. [PMID: 9168944 DOI: 10.1006/bbrc.1997.6550] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effect of thyroid hormone on stearoyl-CoA desaturase gene 1 (SCD1) expression was investigated in mouse liver. Daily injections of 15 micrograms triiodothyronine (T3)/100 g body weight to hypothyroid mice resulted in repression of SCD1 mRNA levels by more than 50% in 48 hours and up to 65% in 6 days. Transient co-transfections were performed with an expression vector for T3 receptor alpha (T3R alpha) in HepG2 cells using chimeric reporter gene constructs of the SCD1 5'-flanking region. Transcriptional repression of the SCD1 putative promoter was observed upon treatment with 100 nM T3 when cotransfected with T3R alpha, but not without cotransfection of receptor. Transient gene expression studies localized a T3 response region to a 70-bp sequence in the SCD1 putative promoter. Eliminating the TATA box and an AP-2 binding site, DNA mobility shift analysis demonstrated specific binding of in vivo nuclear protein from mouse liver nuclear extract to a 43-bp sequence. DNA mobility shift with purified T3R alpha confirmed the presence of a T3 receptor binding site in this thyroid hormone-responsive region. These data indicate that SCD1 contains a negative T3 response region in its proximal promoter.
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Affiliation(s)
- K M Waters
- Department of Biochemistry, University of Wisconsin, Madison 53706, USA
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17
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Kaiser UB, Conn PM, Chin WW. Studies of gonadotropin-releasing hormone (GnRH) action using GnRH receptor-expressing pituitary cell lines. Endocr Rev 1997; 18:46-70. [PMID: 9034786 DOI: 10.1210/edrv.18.1.0289] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- U B Kaiser
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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18
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Satoh T, Yamada M, Iwasaki T, Mori M. Negative regulation of the gene for the preprothyrotropin-releasing hormone from the mouse by thyroid hormone requires additional factors in conjunction with thyroid hormone receptors. J Biol Chem 1996; 271:27919-26. [PMID: 8910392 DOI: 10.1074/jbc.271.44.27919] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
To gain additional insights into the negative gene regulatory action by triiodothyronine (T3), we isolated a 2-kilobase pair 5'-flanking region of the mouse preprothyrotropin-releasing hormone (ppTRH) gene and characterized the DNA elements mediating inhibitory regulation by T3 in the promoter region. In GH4C1 cells, the expression of the 2-kilobase pair mouse ppTRH 5'-flanking region fused to the luciferase reporter gene occurred by transfection and was significantly suppressed by T3. In contrast, T3 suppression was not observed in T3 receptor (T3R)-deficient CV-1 cells, suggesting that T3Rs were required for the negative regulation. Cotransfected mouse T3R alpha1, beta1, and beta2 possessed indistinguishable potency for the negative regulation. Deletion analysis localized the element mediating the negative regulation to the region between -83 and +46, and the sequence downstream of the transcription start site (TSS) between +12 and +46 was found to be essential for the inhibitory regulation. In mobility shift assays, only T3R monomers bound to the element containing a T3 response element half-site at -57. No apparent T3R binding was observed to the element downstream of TSS. Neither the T3 response element half-site nor the element downstream of the TSS confer T3 suppression individually in heterologous promoters. These results indicate that the negative regulation of murine ppTRH gene by T3 might be mediated by the cooperation of T3R monomers with unknown factor(s) interacting with the element downstream of the TSS.
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Affiliation(s)
- T Satoh
- First Department of Internal Medicine, Gunma University School of Medicine, 3-39-15 Showa-machi, Maebashi 371, Japan
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19
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Quirin-Stricker C, Nappey V, Simoni P, Toussaint JL, Schmitt M. Trans-activation by thyroid hormone receptors of the 5' flanking region of the human ChAT gene. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1994; 23:253-65. [PMID: 8057782 DOI: 10.1016/0169-328x(94)90232-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Fusion gene constructs containing the human choline acetyltransferase 5' flanking region are stimulated by thyroid hormone (T3) in neuronal NG108-15 and NE1-115 cells but not in non neuronal COS-1 and JEG-3 cells. To identify potential T3 receptor binding elements (T3RE), chimeric plasmids containing various lengths of the 5' end of the hChAT gene linked to the CAT reporter gene were assayed by transient transfections into NG108-15, NE1-115 and COS-1 cells. We show that regulation is T3 specific as estrogen, dexamethasone, dihydrotestosterone, all-trans-retinoic acid and 9-cis-retinoic acid have no effect. We localized several potential T3REs and characterized the most proximal T3RE (position 3280-3291) which contains two hexameric half-sites arranged as a direct repeat without a base pair spacer. An oligonucleotide containing this sequence confers T3 responsiveness to a heterologous promoter. The transcriptional response of this T3RE is markedly reduced after mutation of the first or second half-site indicating that both half-sites are required for a maximal T3 response. We have found that RAR alpha, RXR alpha and COUP-TF do not enhance T3 responsiveness and therefore they may not interact with T3R alpha in NG108-15 cells on this regulatory sequence. T3R monomer and dimer specific binding to the proximal T3RE is demonstrated by gel-retardation DNA binding assays and by methylation interference experiments. In COS-1 cells, T3R inhibits transcriptional activation by the transcription factor AP-1 whereas in NE1-115 cells T3R enhances AP-1 mediated activation in a T3 dependant fashion. It is likely that these effects involve protein-protein interactions. These results suggest that the T3 receptor can act as a positive transcriptional regulatory factor on the hChAT gene.
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Affiliation(s)
- C Quirin-Stricker
- Institut de Chimie Biologique de la Faculté de Médecine, CNRS, Unité 184, INSERM, Strasbourg, France
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20
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21
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In vitro transcriptional studies of the roles of the thyroid hormone (T3) response elements and minimal promoters in T3-stimulated gene transcription. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)42260-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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22
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An AP-1-like factor and the pituitary-specific factor Pit-1 are both necessary to mediate hormonal induction of human thyrotropin beta gene expression. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)49472-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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23
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Yarwood N, Gurr J, Sheppard M, Franklyn J. Estradiol modulates thyroid hormone regulation of the human glycoprotein hormone alpha subunit gene. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(20)80637-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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24
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25
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Madison LD, Ahlquist JA, Rogers SD, Jameson JL. Negative regulation of the glycoprotein hormone alpha gene promoter by thyroid hormone: mutagenesis of a proximal receptor binding site preserves transcriptional repression. Mol Cell Endocrinol 1993; 94:129-36. [PMID: 7690722 DOI: 10.1016/0303-7207(93)90060-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Transcription of the glycoprotein hormone alpha gene is repressed by the thyroid hormone receptor (TR) in a hormone dependent manner. Previous studies identified a TR binding site immediately downstream of the TATA box. Site directed mutagenesis and transient gene expression studies were used to evaluate the role of this TR binding site as a negative thyroid response element (nTRE). Mutagenesis of the putative negative thyroid response element (nTRE) site eliminated TR binding but failed to eliminate negative regulation by T3. A mutation which converted the putative nTRE to a higher affinity palindromic element did not enhance repression, but rather eliminated thyroid hormone dependent negative regulation. Proximal alpha promoter sequences between -100 and +44 were replaced with a heterologous thymidine kinase promoter resulting in a construct that was not repressed by T3 treatment. This finding confirmed that repression required proximal alpha promoter sequences and also indicated that repression did not occur by interference with the function of upstream the alpha gene enhancers. These studies indicate that TR binding adjacent to the TATA box is not required for T3 mediated repression of the alpha promoter and suggest that negative regulation may involve protein-protein interactions with promoter-specific transcription factors.
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MESH Headings
- Animals
- Base Sequence
- Binding Sites/genetics
- DNA/metabolism
- Enhancer Elements, Genetic
- Glycoprotein Hormones, alpha Subunit/biosynthesis
- Glycoprotein Hormones, alpha Subunit/genetics
- Humans
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Promoter Regions, Genetic/drug effects
- Promoter Regions, Genetic/genetics
- Rats
- Receptors, Thyroid Hormone/metabolism
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/genetics
- Regulatory Sequences, Nucleic Acid/drug effects
- Regulatory Sequences, Nucleic Acid/genetics
- Sequence Deletion
- Transcription, Genetic/drug effects
- Transcription, Genetic/genetics
- Triiodothyronine/pharmacology
- Tumor Cells, Cultured
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Affiliation(s)
- L D Madison
- Thyroid Unit, Massachusetts General Hospital, Boston 02114
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26
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Shull JD, Pennington KL, Rader AE. Promoter region of the rat gene encoding ornithine aminotransferase: transcriptional activity, sequence, and DNase-I-hypersensitive sites. Gene X 1993; 125:169-75. [PMID: 8462871 DOI: 10.1016/0378-1119(93)90324-v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In the rat, the gene (rOAT) encoding ornithine aminotransferase (OAT) is expressed in all cell types examined; however, regulation of rOAT expression is complex and cell-type specific. Various regions of the rOAT 5' flanking domain were cloned upstream from the cat reporter gene, and the expression of these OAT::cat fusions was examined following transfection into rat kidney epithelial cells (NRK-52E), human embryonic kidney cells (293), and rat hepatoma cells (H-4-II-E). Although these experiments suggested the presence of one or more positive regulatory elements between nucleotides -661 and -158, and one or more negative elements upstream from nt -897, none of these putative elements appeared to function in a cell-type-specific manner. The nt sequence of 2531 bp of the rOAT domain flanking the promoter revealed several putative promoter/enhancer elements in positions analogous to the human OAT gene, numerous AGGTCA-like motifs related to the binding sites for the estrogen and thyroid hormone receptors, and multiple motifs resembling a putative regulatory element associated with genes encoding enzymes of the urea cycle. Finally, sensitivity of the 5' end of rOAT to cleavage by DNase I was examined, as DNase-I-hypersensitive sites (DHS) are often found in association with cis-acting regulatory elements. Two DHS were identified; one DHS approximately 140 bp upstream, and the second DHS approximately 300 bp downstream, of the transcription start point (tsp). These data provide the foundation upon which to base future studies aimed at elucidating the molecular mechanisms through which rOAT expression is regulated in a cell-type specific manner.
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Affiliation(s)
- J D Shull
- Eppley Institute for Research in Cancer and Allied Disease, University of Nebraska Medical Center, Omaha 68198-6805
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27
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Chin WW, Carr FE, Burnside J, Darling DS. Thyroid hormone regulation of thyrotropin gene expression. RECENT PROGRESS IN HORMONE RESEARCH 1993; 48:393-414. [PMID: 8441852 DOI: 10.1016/b978-0-12-571148-7.50018-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Thyroid hormones suppress the synthesis and release of thyrotropin from thyrotropes in the anterior pituitary gland, a feature that is critical in the classic negative-feedback loop of the pituitary-thyroid endocrine axis. The major effect of thyroid hormones in this system is exerted at the transcriptional level. The molecular mechanisms by which there is negative regulation of TSH subunit gene expression by thyroid hormone have been elucidated. The TSH subunit genes have isolated and characterized. Structure-function analyses using fusion genes and DNA transfection approaches have defined the putative negative TREs among the promoters of the rat, mouse, and human alpha and TSH beta genes. These sequences are either largely overlapping direct TRE half-sites, TRE half-sites as direct repeats gapped by two nucleotides, or single TRE half-sites. These arrangements are distinct from those seen in positive TREs. Recent knowledge regarding the molecular mechanisms of thyroid action in general forces consideration of multiple TR isoforms, TR heterodimer partners (TRAPs), and thyroid hormones in the ultimate mechanisms of negative action. Several models have been proposed, but none has yet been proved. In addition, the role of thyroid hormone in the regulation of gene expression at the posttranscriptional level is beginning to be addressed. Future work should continue to illuminate these important facets of gene regulation.
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Affiliation(s)
- W W Chin
- Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts
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28
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Yen P, Sugawara A, Chin W. Triiodothyronine (T3) differentially affects T3-receptor/retinoic acid receptor and T3-receptor/retinoid X receptor heterodimer binding to DNA. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)50083-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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29
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Carr F, Kaseem L, Wong N. Thyroid hormone inhibits thyrotropin gene expression via a position-independent negative L-triiodothyronine-responsive element. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)37016-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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30
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Hu RM, Sakurai A, Miyamoto T, DeGroot LJ. Expression and function of a human thyroid hormone receptor-derived DNA-binding domain protein. Mol Cell Endocrinol 1992; 84:209-17. [PMID: 1587392 DOI: 10.1016/0303-7207(92)90032-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
DNA binding domain proteins (DBDP) were prepared using a pET construct containing an insert coding for amino acids 49-122 of human thyroid hormone receptor (hTR) alpha and 103-179 of hTR beta. These proteins were expressed in Escherichia coli strain BL21 (DE3)-plysS after induction by isopropyl-D-thiogalactopyranoside (IPTG). The hTR alpha and hTR beta DBDP contain respectively 79 and 82 amino acids, including an amino terminal 4 amino acid extension derived from pET-3a or the synthesized initiation codon. Using a gel shift assay, both DBDPs were found to bind to a DNA oligonucleotide containing a thyroid hormone response element (TRE). The DBDPs competed with full length hTR alpha 1 for binding to the oligonucleotide. Apo-DBDPs (Zn2+ released by low pH) failed to bind to the palindromic TRE. DNA binding is restored however if apo-DBDP is preincubated in 500 microM Zn2+. When the DBDPs were expressed in COS-7 cells using a pCB6+ expression vector, they did not induce expression of a TRE-CAT fusion gene. hTR DBDPs thus can bind to DNA, presumably as monomers, since they do not contain the leucine zipper-like motif for dimerization. In COS-7 cells, they fail to cause transactivation of a TRE-CAT fusion gene. It is inferred that this may be because the DBDPs are not translocated to the nucleus or lack a transactivation domain.
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Affiliation(s)
- R M Hu
- Department of Medicine, University of Chicago, IL 60637
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31
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Sarapura VD, Wood WM, Gordon DF, Ridgway EC. A cell line that produces the glycoprotein hormone alpha-subunit contains specific nuclear factors similar to those present in thyrotropes. Thyroid 1992; 2:31-8. [PMID: 1381977 DOI: 10.1089/thy.1992.2.31] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A unique characteristics of thyrotrope-specific gene expression is the coordinated expression and regulation of the alpha- and beta-subunits of TSH. A cell line (alpha TSH) derived from the transplantable mouse thyrotropic tumor MGH101A, which no longer expresses the TSH beta-subunit gene but continues to secrete large amounts of alpha-subunit, was used as a model to study alpha-subunit gene expression independent from the TSH beta-subunit gene and was compared with the expression in TSH-secreting TtT97 tumors. Transient transfection studies showed a striking similarity in the activity of 5' deletions of the mouse alpha-subunit gene promoter in both alpha TSH and TtT97 cells and localized two regions important for expression that spanned 100 base pairs, from -480 to -417 and from -417 to -381. These regions were found to have no activity in nonthyrotrope pituitary GH4 cells and L-cell fibroblasts. Analysis of the alpha-subunit 5' flanking DNA interactions with alpha TSH and TtT97 nuclear extracts showed two DNase I protected sequences, from -474 to -452 and from -447 to -400, both of which colocalized with the functionally important regions. Gel retardation analysis demonstrated the specificity of these interactions, and a similar migration of the DNA-protein complexes suggested that protein factors were similar in the two cell types. We conclude that the nuclear factors necessary for alpha-subunit expression in thyrotropes are retained in alpha TSH cells. Moreover, since alpha TSH cells do not express the TSH beta-subunit gene, the factors that determine the expression of the alpha-subunit may not be sufficient for TSH beta-subunit gene expression.
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Affiliation(s)
- V D Sarapura
- Department of Medicine, University of Colorado Health Sciences Center, Denver
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32
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Leidig F, Shepard AR, Zhang WG, Stelter A, Cattini PA, Baxter JD, Eberhardt NL. Thyroid hormone responsiveness in human growth hormone-related genes. Possible correlation with receptor-induced DNA conformational changes. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)48371-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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33
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A detailed functional and structural analysis of a major thyroid hormone inhibitory element in the human thyrotropin beta-subunit gene. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54688-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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34
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Clayton RN, Lalloz MR, Salton SR, Roberts JL. Expression of luteinising hormone-beta subunit chloramphenicol acetyltransferase (LH-beta-CAT) fusion gene in rat pituitary cells: induction by cyclic 3'-adenosine monophosphate (cAMP). Mol Cell Endocrinol 1991; 80:193-202. [PMID: 1659545 DOI: 10.1016/0303-7207(91)90156-m] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In this study we determined the activity of the rat luteinising hormone-beta gene promoter in a heterologous rat pituitary cell line (GH3 cells). 1.7 kb of LH-beta 5' flanking sequence and the first 5 bp of the 5' untranslated region were ligated to the chloramphenicol acetyltransferase (CAT) receptor gene (LH-beta-CAT) and transiently transfected by calcium phosphate precipitation into subconfluent cultures of GH3 cells. Basal low-level CAT activity was only detected in GH3 cells, being absent in two non-pituitary cell lines (BeWo and HeLa) RNase analysis revealed that mRNA from transfected GH3 cells protected a fragment of labelled antisense probe of correct size for transcription initiation from the LH-beta CAP site, confirming that promoter activity reflected correctly initiated LH-beta-CAT fusion gene transcripts. CAT activity was consistently induced by an average of 3-5-fold from the full-length 1.7 kb promoter, in a dose- and time-dependent manner, by forskolin, dibutyryl cAMP, and 8-bromo cAMP implying presence of a cAMP-responsive cis-acting domain in the LH-beta promoter region. Transfection of deletion mutants delta-615-CAT, delta-385-CAT and delta-250-CAT each reduced forskolin inducibility to 1.7-fold but did not abolish induction completely suggesting a domain between -1.7 and -0.6 kb contained a cAMP-responsive element(s) (CRE). Further deletion of LH-beta 5' flanking sequences to delta-85-CAT restored forskolin induction to wild-type levels (3-5-fold), suggesting the presence of a weak inhibitory element between -600 and -85 kb, and a cAMP-responsive domain in the proximal promoter region. The LH-beta promoter does not contain perfect tandem repeat palindromic CRE DNA sequences, though there are several octanucleotide sequences differing by only 1 bp from AP-2 binding sites, the consensus CRE, and the vasointestinal peptide gene CRE. Although these data suggest that the LH-beta gene is cAMP responsive this is likely mediated by several and complex protein interactions with multiple DNA sequences in the proximal and distal LH-beta promoter enhancer.
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Affiliation(s)
- R N Clayton
- Endocrinology Research Group, Clinical Research Centre, Harrow, Middlesex, U.K
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35
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Voz M, Peers B, Belayew A, Martial J. Characterization of an unusual thyroid response unit in the promoter of the human placental lactogen gene. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98853-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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36
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Umesono K, Murakami KK, Thompson CC, Evans RM. Direct repeats as selective response elements for the thyroid hormone, retinoic acid, and vitamin D3 receptors. Cell 1991; 65:1255-66. [PMID: 1648450 PMCID: PMC6159884 DOI: 10.1016/0092-8674(91)90020-y] [Citation(s) in RCA: 1326] [Impact Index Per Article: 40.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report here the identification of thyroid hormone response elements (TREs) that consist of a direct repeat, not a palindrome, of the half-sites. Unlike palindromic TREs, direct repeat TREs do not confer a retinoic acid response. The tandem TRE can be converted into a retinoic acid response element by increasing the spacing between the half-sites by 1 nucleotide, and the resulting retinoic acid response element is no longer a TRE. Decreasing the half-site spacing by 1 nucleotide converts the TRE to a vitamin D3 response element, while eliminating response to T3. These results correlate well with DNA-binding affinities of the thyroid hormone, retinoic acid, and vitamin D3 receptors. This study points to the general importance of tandem repeat hormone response elements and suggests a simple physiologic code exists in which half-site spacing plays a critical role in achieving selective hormonal response.
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Affiliation(s)
- K Umesono
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, San Diego, California 92186-5800
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Näär AM, Boutin JM, Lipkin SM, Yu VC, Holloway JM, Glass CK, Rosenfeld MG. The orientation and spacing of core DNA-binding motifs dictate selective transcriptional responses to three nuclear receptors. Cell 1991; 65:1267-79. [PMID: 1648451 DOI: 10.1016/0092-8674(91)90021-p] [Citation(s) in RCA: 491] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Characterization of several thyroid hormone (T3), retinoic acid, and estrogen response elements has led to the identification of conserved DNA half-sites (core binding motifs). We present evidence that differences in both the relative orientation and spacing of these motifs within hormone response elements determine the distinct transcriptional responses of three members of the nuclear receptor superfamily. When separated by 3 bp, direct repeat, palindromic, and inverted palindromic arrangements of these motifs impart selective transcriptional responses to retinoic acid, estrogen, and T3 receptors, respectively. Varying the spacing between core motifs alters the specificity. Without spacing, a direct repeat of the core motif paradoxically configures the T3 receptor to confer transactivation in the absence of T3 and repression in its presence. Such an element occurs naturally in the mouse beta-thyrotropin promoter, physiologically under negative regulation by T3. The orientation and spacing of core binding motifs may thus function in concert as a code that accounts for the selective patterns of transcriptional responses of hormonally regulated promoters.
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Affiliation(s)
- A M Näär
- Eukaryotic Regulatory Biology Program, University of California, San Diego School of Medicine, La Jolla 92093-0648
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38
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Golos TG, Durning M, Fisher JM. Molecular cloning of the rhesus glycoprotein hormone alpha-subunit gene. DNA Cell Biol 1991; 10:367-80. [PMID: 1713773 DOI: 10.1089/dna.1991.10.367] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A rhesus monkey genomic library was screened with a cDNA for the glycoprotein hormone alpha-subunit. Genomic clones hybridizing with exon-specific probes were selected and the DNA sequences were determined for 1.6 kb of 5'-flanking DNA, all four exons, the second and third introns, all exon-intron junctions, and 357 bp of 3'-flanking DNA. Comparison with the 236 bp of 5'-flanking sequence data available for the human alpha gene indicates an overall homology of 95%. Primer extension analysis of rhesus placental and pituitary mRNA demonstrated that transcription initiation is identical to that in the human placenta. The rhesus gene contains an element nearly identical (21/22 bases) to the placental tissue-specific element described for the human alpha gene. The rhesus gene has only one copy of the cAMP-response element (CRE), which is present as a direct repeat in the human gene. The rhesus CRE contains the consensus core sequence TGACG-TCA with the cytosine in the fourth position that is essential for placental expression of the human gene. The 5'-flanking region also has elements highly homologous to the consensus estrogen and progesterone/glucocorticoid response elements, as well as thyrotrope-specific and Pit-1-like binding sites described in rodent genes. The nucleotide sequence of four exons (predicted mRNA) have an aggregate homology of 92.7% with the human sequence. However, a 12-bp insertion to the second exon results in the addition of 4 amino acids to the amino-terminal end of the protein; these are homologous with the proteins of nonprimates but are lacking in the human alpha-subunit. The amino acid sequence of the deduced protein was slightly more homologous with the bovine than the human protein (91.6% vs. 89.6%). Thus, the rhesus glycoprotein alpha-subunit gene codes for a protein whose structure somewhat more closely resembles that of lower species, but the 5'-flanking DNA of the gene has gained the elements necessary for transcription in the placental syncytiotrophoblast which distinguishes the primate placenta from the other species examined.
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Affiliation(s)
- T G Golos
- Wisconsin Regional Primate Research Center, University of Wisconsin, Madison 53715-1299
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Showers MO, Darling DS, Kieffer GD, Chin WW. Isolation and characterization of a cDNA encoding a chicken beta thyroid hormone receptor. DNA Cell Biol 1991; 10:211-21. [PMID: 1707280 DOI: 10.1089/dna.1991.10.211] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have isolated and characterized a cDNA encoding a chicken beta homolog of c-erbA, or thyroid hormone receptor (TR). Chicken liver cDNA libraries were screened with a rat TR beta-1 cDNA probe, and several cDNA inserts were isolated and characterized. The sequence of one cDNA predicts a 369-amino-acid open reading frame (ORF), with a protein sequence that possesses 96% identity with that of rat TR beta-1, but only 88% identity with chicken TR alpha. These data indicate that the cDNA likely encodes a beta form of TR that has the expected putative DNA and T3 binding domains. The chicken TR beta (chTR beta) in vitro translated protein binds T3 with high affinity, and binds both the thyroid hormone response element (TRE) from the rat growth hormone gene and the Xenopus vitellogenin A2 gene estrogen response element (ERE), similarly to that of the rat TR beta-1. Northern blot analysis revealed the expression of a 7.0-kb RNA in several tissues including cerebellum, pituitary, kidney, and liver. This chicken liver TR beta cDNA sequence varies in both the 5' and 3' untranslated regions from the chicken kidney TR beta cDNA sequence recently reported (Forrest et al., 1990). The 5' untranslated cDNA sequence divergence occurs near a potential splice site junction of the human TR beta gene, suggesting that this chicken liver cDNA may represent an alternatively spliced RNA product of the chicken TR beta gene.
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Affiliation(s)
- M O Showers
- Department of Medicine, Brigham and Women's Hospital, Boston, MA
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GLASS CHRISTOPHERK, ROSENFELD MICHAELG. Regulation of gene transcription by thyroid hormones and retinoic acid. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/b978-0-444-81382-4.50013-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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41
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Luo D, McKeown BA. The effect of thyroid hormone and glucocorticoids on carp growth hormone-releasing factor (GRF)-induced growth hormone (GH) release in rainbow trout (Oncorhynchus mykiss). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1991; 99:621-6. [PMID: 1679699 DOI: 10.1016/0300-9629(91)90140-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
1. The effect of thyroid hormone and glucocorticoids on carp growth hormone-releasing factor (GRF)-induced growth hormone (GH) secretion was studied on rainbow trout using a dispersed pituitary cell culture system. 2. A combined administration of lower doses (0.01 microM) of 3,5,3'-triiodo-L-thyronine (T3) and dexamethasone (Dex) significantly increased spontaneous as well as carp GRF-induced GH release. 3. Lower doses of Dex alone had no effect, and T3 had a marginal effect on GH release. Higher doses of either Dex or T3 potentially reduced GH release. 4. This study indicates an important role of thyroid hormone and/or glucocorticoids in the hypothalamic regulation of GH secretion in fish.
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Affiliation(s)
- D Luo
- Department of Biological Sciences, Simon Fraser University, Burnaby, B.C., Canada
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42
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Desvergne B, Petty KJ, Nikodem VM. Functional characterization and receptor binding studies of the malic enzyme thyroid hormone response element. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(17)35275-4] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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43
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Glass CK, Holloway JM. Regulation of gene expression by the thyroid hormone receptor. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1032:157-76. [PMID: 2261492 DOI: 10.1016/0304-419x(90)90002-i] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- C K Glass
- Eukaryotic Regulatory Biology Program Center for Molecular Genetics, University of California, San Diego School of Medicine, La Jolla 92093
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Gurr JA, Januszeski MM, Tidikis IM, Norcross JJ, Kourides IA. Thyroid hormone regulates expression of the thyrotropin beta-subunit gene from both transcription start sites in the mouse and rat. Mol Cell Endocrinol 1990; 71:185-93. [PMID: 2210030 DOI: 10.1016/0303-7207(90)90024-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Thyroid hormones suppress transcription of the gene for the beta-subunit of thyrotropin (TSH beta). Since the TSH beta gene in both the mouse and the rat contains two start sites of transcription in exon 1, we have investigated whether expression of the gene from each start site is differentially regulated by thyroid hormones in each species. RNase protection analysis was used to assay the levels of mRNA specifically transcribed from the upstream (TSS 1) and downstream (TSS 2) transcription start sites in the mouse and rat pituitary. In euthyroid and hypothyroid pituitaries there was an approximately 5-fold and 2-fold greater abundance of mRNA derived from TSS 2 than TSS 1, respectively. Hypothyroidism induced an 18- and a 9-fold increase in TSH beta gene expression from TSS 1 and TSS 2, respectively. Treatment of hypothyroid animals for 1 day with triiodothyronine (T3) reduced expression from both start sites by about 50%; after 4 days of T3 treatment, TSH beta mRNAs derived from both start sites were below detectable levels. These results were confirmed in the rat by primer extension analysis. Expression from TSS 1 in the mouse was also shown to be dependent on thyroid status using the polymerase chain reaction (PCR) technique. In contrast to previous results from primer extension studies, PCR analysis demonstrated that alternative splicing of the TSH beta RNA primary transcript can occur when transcription is initiated at the upstream start site. We conclude that, in both the mouse and the rat pituitary, expression of the TSH beta gene from both transcription start sites is regulated by thyroid hormones.
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Affiliation(s)
- J A Gurr
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140
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45
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Zilz ND, Murray MB, Towle HC. Identification of multiple thyroid hormone response elements located far upstream from the rat S14 promoter. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39048-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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46
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Petty KJ, Desvergne B, Mitsuhashi T, Nikodem VM. Identification of a thyroid hormone response element in the malic enzyme gene. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39126-4] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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47
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Iwasa Y, Aida K, Yokomori N, Inoue M, Onaya T. Transcriptional regulation of ferritin heavy chain messenger RNA expression by thyroid hormone. Biochem Biophys Res Commun 1990; 167:1279-85. [PMID: 2322273 DOI: 10.1016/0006-291x(90)90662-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effect of 3,5,3'-triiodo-L-thyronine (T3) on the steady state levels of ferritin heavy chain (ferritin H) mRNA in cultured rat glioma C6 cells and various rat tissues was examined. Addition of T3 to cultured C6 cells showed the time and dose-dependent increase in the steady-state level of ferritin H mRNA. In vitro nuclear run-on assay revealed that the stimulatory effect was due to the increase in the transcription rate of ferritin H gene. T3 had no effect on the half life of ferritin H mRNA. In hyperthyroid rats, the level of ferritin H mRNA in the kidney was elevated. On the contrary, that was decreased in hypothyroid rats. The results suggest the involvement of T3 in the regulation of ferritin H gene expression.
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Affiliation(s)
- Y Iwasa
- Third Department of Internal Medicine, University of Yamanashi Medical School, Japan
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48
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A nuclear factor that enhances binding of thyroid hormone receptors to thyroid hormone response elements. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39828-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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