Genetic dissection of gluco- and mineralocorticoid receptor function in mice

2003 ◽  
Vol 75 (11-12) ◽  
pp. 1699-1707
Author(s):  
E. F. Greiner ◽  
S. Berger ◽  
G. Schütz
Keyword(s):  
Mineralocorticoid Receptor ◽  
Hormone Receptors ◽  
Target Genes ◽  
Genetic Network ◽  
Nuclear Hormone Receptor ◽  
Genetic Dissection ◽  
Transcriptional Responses ◽  
Protein Protein Interaction

Nuclear hormone receptors function to transduce hormonal signals into transcriptional responses by controlling the activity of specific target genes. These target genes comprise a genetic network whose coordinate activity defines the physiological responses to hormonal signals. Dissecting nuclear hormone receptor functions in vivo by gene inactivation and transgenic strategies represents an invaluable and powerful approach to increase our knowledge of these genetic networks and their physiological functions. Glucocorticoids and mineralocorticoids are involved in numerous physiological processes important to maintain metabolic, cardiovascular, central nervous, and immune system homeostasis. Germline and somatic gene targeting as well as an increased dosage of the glucocorticoid receptor (GR) allows the characterization of the various functions and molecular modes of action of this receptor. Most of the effects of the GR are mediated via activation and repression of gene expression. To separate activating from repressing functions of the GR, a point mutation was introduced which allowed us to characterize and distinguish functions dependent on GR binding to DNA from those mediated by protein/protein interaction. Cell/tissue-specific mutations of the gluco- and mineralocorticoid receptor is the basis for the evaluation of their cell-specific functions, including the characterization of target genes of the receptors in order to describe their specific effects on different targets.

scholarly journals NRC-Interacting Factor 1 Is a Novel Cotransducer That Interacts with and Regulates the Activity of the Nuclear Hormone Receptor Coactivator NRC

2002 ◽  
Vol 22 (19) ◽  
pp. 6883-6894 ◽  
Author(s):  
Muktar A. Mahajan ◽  
Audrey Murray ◽  
Herbert H. Samuels
Keyword(s):  
Amino Acid ◽  
Transcriptional Activation ◽  
Transcriptional Activity ◽  
Hormone Receptors ◽  
Nuclear Protein ◽  
Zinc Fingers ◽  
Nuclear Hormone Receptor ◽  
Coactivator Complex

ABSTRACT We previously reported the cloning and characterization of a novel nuclear hormone receptor transcriptional coactivator, which we refer to as NRC. NRC is a 2,063-amino-acid nuclear protein which contains a potent N-terminal activation domain and several C-terminal modules which interact with CBP and ligand-bound nuclear hormone receptors as well as c-Fos and c-Jun. In this study we sought to clone and identify novel factors that interact with NRC to modulate its transcriptional activity. Here we describe the cloning and characterization of a novel protein we refer to as NIF-1 (NRC-interacting factor 1). NIF-1 was cloned from rat pituitary and human cell lines and was found to interact in vivo and in vitro with NRC. NIF-1 is a 1,342-amino-acid nuclear protein containing a number of conserved domains, including six Cys-2/His-2 zinc fingers, an N-terminal stretch of acidic amino acids, and a C-terminal leucine zipper-like motif. Zinc fingers 1 to 3 are potential DNA-binding BED finger domains recently proposed to play a role in altering local chromatin architecture. We mapped the interaction domains of NRC and NIF-1. Although NIF-1 does not directly interact with nuclear receptors, it markedly enhances ligand-dependent transcriptional activation by nuclear hormone receptors in vivo as well as activation by c-Fos and c-Jun. These results, and the finding that NIF-1 interacts with NRC in vivo, suggest that NIF-1 functions to regulate transcriptional activation through NRC. We suggest that NIF-1, and factors which associate with coactivators but not receptors, be referred to as cotransducers, which act in vivo either as part of a coactivator complex or downstream of a coactivator complex to modulate transcriptional activity. Our findings suggest that NIF-1 may be a functional component of an NRC complex and acts as a regulator or cotransducer of NRC function.

scholarly journals 30 YEARS OF THE MINERALOCORTICOID RECEPTOR: Coregulators as mediators of mineralocorticoid receptor signalling diversity

2017 ◽  
Vol 234 (1) ◽  
pp. T23-T34 ◽  
Author(s):  
Peter J Fuller ◽  
Jun Yang ◽  
Morag J Young
Keyword(s):  
Protein Interactions ◽  
Mineralocorticoid Receptor ◽  
Hormone Receptors ◽  
Target Genes ◽  
Steroid Hormone Receptors ◽  
Protein Protein Interactions ◽  
Transcriptional Responses ◽  
Functional Roles ◽  
Regulatory Processes ◽  
Coregulatory Proteins

The cloning of the mineralocorticoid receptor (MR) 30 years ago was the start of a new era of research into the regulatory processes of MR signalling at target genes in the distal nephron, and subsequently in many other tissues. Nuclear receptor (NR) signalling is modified by interactions with coregulatory proteins that serve to enhance or inhibit the gene transcriptional responses. Over 400 coregulatory proteins have been described for the NR super family, many with functional roles in signalling, cellular function, physiology and pathophysiology. Relatively few coregulators have however been described for the MR although recent studies have demonstrated both ligand and/or tissue selectivity for MR-coregulator interactions. A full understanding of the cell, ligand and promoter-specific requirements for MR-coregulator signalling is an essential first step towards the design of small molecular inhibitors of these protein-protein interactions. Tissue-selective steroidal or non-steroidal modulators of the MR are also a desired therapeutic goal. Selectivity, as for other steroid hormone receptors, will probably depend on differential expression and recruitment of coregulatory proteins.

scholarly journals Do unliganded thyroid hormone receptors have physiological functions?

2003 ◽  
Vol 31 (1) ◽  
pp. 9-20 ◽  
Author(s):  
O Chassande
Keyword(s):  
Thyroid Hormone ◽  
Hormone Receptors ◽  
Target Genes ◽  
Thyroid Hormone Receptors ◽  
Intrinsic Activity ◽  
Vertebrate Development ◽  
Transcriptional Responses ◽  
Embryonic And Fetal Development

Thyroid hormone (TH) is required for the development of vertebrates and exerts numerous homeostatic functions in adults. TH acts through nuclear receptors which control the transcription of target genes. Unliganded and liganded thyroid hormone receptors (TRs) have been shown to exert opposite effects on the transcription of target genes in vitro. However, the occurance of an aporeceptor activity in vivo and its potential physiological significance has not been clearly addressed. Several data generated using experimental hypothyroidism and thyrotoxicosis in wild type and TR knockout mice support the notion that apoTRs have an intrinsic activity in several tIssues. ApoTRs, and in particular TRalpha1, are predominant during the early stages of vertebrate development and must be turned into holoTRs for post-natal development to proceed normally. However, the absence of striking alterations of embryonic and fetal development in mice devoid of TRs indicates that apoTRs do not play a fundamental role. During development, as well as in adults, apoTRs rather appears as a system which increases the range of transcriptional responses to moderate variations of T3.

Nuclear Hormone Receptors and Gene Expression

2001 ◽  
Vol 81 (3) ◽  
pp. 1269-1304 ◽  
Author(s):  
Ana Aranda ◽  
Angel Pascual
Keyword(s):  
Gene Expression ◽  
Nuclear Receptors ◽  
Transcriptional Activation ◽  
Transcriptional Repression ◽  
Hormone Receptors ◽  
Target Genes ◽  
Specific Interaction ◽  
Nuclear Hormone Receptor ◽  
Transcriptional Responses ◽  
Orphan Receptors

The nuclear hormone receptor superfamily includes receptors for thyroid and steroid hormones, retinoids and vitamin D, as well as different “orphan” receptors of unknown ligand. Ligands for some of these receptors have been recently identified, showing that products of lipid metabolism such as fatty acids, prostaglandins, or cholesterol derivatives can regulate gene expression by binding to nuclear receptors. Nuclear receptors act as ligand-inducible transcription factors by directly interacting as monomers, homodimers, or heterodimers with the retinoid X receptor with DNA response elements of target genes, as well as by “cross-talking” to other signaling pathways. The effects of nuclear receptors on transcription are mediated through recruitment of coregulators. A subset of receptors binds corepressor factors and actively represses target gene expression in the absence of ligand. Corepressors are found within multicomponent complexes that contain histone deacetylase activity. Deacetylation leads to chromatin compactation and transcriptional repression. Upon ligand binding, the receptors undergo a conformational change that allows the recruitment of multiple coactivator complexes. Some of these proteins are chromatin remodeling factors or possess histone acetylase activity, whereas others may interact directly with the basic transcriptional machinery. Recruitment of coactivator complexes to the target promoter causes chromatin decompactation and transcriptional activation. The characterization of corepressor and coactivator complexes, in concert with the identification of the specific interaction motifs in the receptors, has demonstrated the existence of a general molecular mechanism by which different receptors elicit their transcriptional responses in target genes.

scholarly journals Structural and Functional Characterization of the Interdomain Interaction in the Mineralocorticoid Receptor

2009 ◽  
Vol 23 (9) ◽  
pp. 1360-1370 ◽  
Author(s):  
Jyotsna B. Pippal ◽  
Yizhou Yao ◽  
Fraser M. Rogerson ◽  
Peter J. Fuller
Keyword(s):  
Mineralocorticoid Receptor ◽  
Functional Characterization ◽  
Glutathione S Transferase ◽  
Protein Protein Interaction ◽  
Functional Differences ◽  
Electrolyte Homeostasis ◽  
Interdomain Interaction ◽  
Two Hybrid

Abstract The mineralocorticoid receptor (MR) plays a central role in electrolyte homeostasis and in cardiovascular disease. We have previously reported a ligand-dependent N/C-interaction in the MR. In the present study we sought to fully characterize the MR N/C-interaction. By using a range of natural and synthetic MR ligands in a mammalian two-hybrid assay we demonstrate that in contrast to aldosterone, which strongly induces the interaction, the physiological ligands deoxycorticosterone and cortisol weakly promote the interaction but predominantly inhibit the aldosterone-mediated N/C-interaction. Similarly, progesterone and dexamethasone antagonize the interaction. In contrast, the synthetic agonist 9α-fludrocortisol robustly induces the interaction. The ability of the N/C interaction to discriminate between MR agonists suggests a subtle conformational difference in the ligand-binding domain induced by these agonists. We also demonstrate that the N/C interaction is not cell specific, consistent with the evidence from a glutathione-S-transferase pull-down assay, of a direct protein-protein interaction between the N- and C-terminal domains of the MR. Examination of a panel of deletions in the N terminus suggests that several regions may be critical to the N/C-interaction. These studies have identified functional differences between physiological MR ligands, which suggest that the ligand-specific dependence of the N/C-interaction may contribute to the differential activation of the MR that has been reported in vivo.

scholarly journals Mediator complex subunit Med19 binds directly GATA transcription factors and is required with Med1 for GATA-driven gene regulation in vivo

2020 ◽  
Vol 295 (39) ◽  
pp. 13617-13629
Author(s):  
Clément Immarigeon ◽  
Sandra Bernat-Fabre ◽  
Emmanuelle Guillou ◽  
Alexis Verger ◽  
Elodie Prince ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Target Genes ◽  
Direct Interaction ◽  
Mediator Complex ◽  
Loss Of Function ◽  
Transcriptional Responses ◽  
Rna Pol Ii ◽  
Evolutionarily Conserved

The evolutionarily conserved multiprotein Mediator complex (MED) serves as an interface between DNA-bound transcription factors (TFs) and the RNA Pol II machinery. It has been proposed that each TF interacts with a dedicated MED subunit to induce specific transcriptional responses. But are these binary partnerships sufficient to mediate TF functions? We have previously established that the Med1 Mediator subunit serves as a cofactor of GATA TFs in Drosophila, as shown in mammals. Here, we observe mutant phenotype similarities between another subunit, Med19, and the Drosophila GATA TF Pannier (Pnr), suggesting functional interaction. We further show that Med19 physically interacts with the Drosophila GATA TFs, Pnr and Serpent (Srp), in vivo and in vitro through their conserved C-zinc finger domains. Moreover, Med19 loss of function experiments in vivo or in cellulo indicate that it is required for Pnr- and Srp-dependent gene expression, suggesting general GATA cofactor functions. Interestingly, Med19 but not Med1 is critical for the regulation of all tested GATA target genes, implying shared or differential use of MED subunits by GATAs depending on the target gene. Lastly, we show a direct interaction between Med19 and Med1 by GST pulldown experiments indicating privileged contacts between these two subunits of the MED middle module. Together, these findings identify Med19/Med1 as a composite GATA TF interface and suggest that binary MED subunit–TF partnerships are probably oversimplified models. We propose several mechanisms to account for the transcriptional regulation of GATA-targeted genes.

scholarly journals Promoter-Specific Roles for Liver X Receptor/Corepressor Complexes in the Regulation of ABCA1 and SREBP1 Gene Expression

2003 ◽  
Vol 23 (16) ◽  
pp. 5780-5789 ◽  
Author(s):  
Brandee L. Wagner ◽  
Annabel F. Valledor ◽  
Gang Shao ◽  
Chris L. Daige ◽  
Eric D. Bischoff ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Hormone Receptors ◽  
Target Genes ◽  
Density Lipoprotein ◽  
Hdl Cholesterol ◽  
Whole Body ◽  
Abca1 Gene ◽  
Element Binding Protein ◽  
X Receptors

ABSTRACT Liver X receptors (LXRs) regulate the expression of genes involved in cholesterol and fatty acid homeostasis, including the genes for ATP-binding cassette transporter A1 (ABCA1) and sterol response element binding protein 1 (SREBP1). Loss of LXR leads to derepression of the ABCA1 gene in macrophages and the intestine, while the SREBP1c gene remains transcriptionally silent. Here we report that high-density-lipoprotein (HDL) cholesterol levels are increased in LXR-deficient mice, suggesting that derepression of ABCA1 and possibly other LXR target genes in selected tissues is sufficient to result in enhanced HDL biogenesis at the whole-body level. We provide several independent lines of evidence indicating that the repressive actions of LXRs are dependent on interactions with the nuclear receptor corepressor (NCoR) and the silencing mediator of retinoic acid and thyroid hormone receptors (SMRT). While dissociation of NCoR and SMRT results in derepression of the ABCA1 gene in macrophages, it is not sufficient for derepression of the SREBP1c gene. These findings reveal differential requirements for corepressors in the regulation of genes involved in cholesterol and fatty acid homeostasis and raise the possibility that these interactions may be exploited to develop synthetic ligands that selectively modulate LXR actions in vivo.

Abstract P244: Transcriptional Regulation of Cardiac Gene Expression by Med13 Alters Global Energy Balance

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Chad E Grueter ◽  
Brett A Johnson ◽  
Xiaoxia Qi ◽  
John McAnally ◽  
Rhonda Bassel-Duby ◽  
...  
Keyword(s):  
Gene Expression ◽  
Energy Balance ◽  
Hormone Receptor ◽  
Hormone Receptors ◽  
Target Genes ◽  
Thyroid Hormone Receptor ◽  
Cardiac Contractility ◽  
Nuclear Hormone Receptor ◽  
Mediator Complex

Aberrant cardiac metabolism is associated with obesity, type 2 diabetes and heart failure. The heart requires highly efficient metabolism to maintain the levels of ATP needed for contractility and pump function, however little is known about the role of the heart as a metabolic organ. Nuclear hormone receptors, such as thyroid hormone receptor play an important role in cardiovascular disease by significantly altering expression of genes involved in maintaining metabolic activity. The Mediator, a large multiprotein complex functions as a hub to control gene expression through association with transcriptional activators and repressors. We tested the hypothesis that Med13, a component of the Mediator complex, regulates cardiac function in a gain-of-function mouse model. Trangsenic mice overexpressing Med13 in the heart are lean, have increased energy expenditure, are resistant to high fat diet-induced obesity and have enhanced cardiac contractility. Microarray analysis and biochemical assays show that in vivo and in vitro Med13 selectively inhibits nuclear hormone receptor target genes of energy metabolism. These results implicate the Mediator complex regulates energy balance and cardiac contractility and suggests that the heart may function as a key component of mammalian energy homeostasis.

scholarly journals PRIC295, a Nuclear Receptor Coactivator, Identified from PPAR-Interacting Cofactor Complex

PPAR Research ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
Sean R. Pyper ◽  
Navin Viswakarma ◽  
Yuzhi Jia ◽  
Yi-Jun Zhu ◽  
Joseph D. Fondell ◽  
...  
Keyword(s):  
Nuclear Receptor ◽  
Target Genes ◽  
Peroxisome Proliferator ◽  
Dependent Manner ◽  
Peroxisome Proliferator Activated Receptor ◽  
Nuclear Receptor Coactivator ◽  
Evolutionarily Conserved

The peroxisome proliferator-activated receptor- (PPAR) plays a key role in lipid metabolism and energy combustion. Chronic activation of PPAR in rodents leads to the development of hepatocellular carcinomas. The ability of PPAR to induce expression of its target genes depends on Mediator, an evolutionarily conserved complex of cofactors and, in particular, the subunit 1 (Med1) of this complex. Here, we report the identification and characterization of PPAR-interacting cofactor (PRIC)-295 (PRIC295), a novel coactivator protein, and show that it interacts with the Med1 and Med24 subunits of the Mediator complex. PRIC295 contains 10 LXXLL signature motifs that facilitate nuclear receptor binding and interacts with PPAR and five other members of the nuclear receptor superfamily in a ligand-dependent manner. PRIC295 enhances the transactivation function of PPAR, PPAR, and ER. These data demonstrate that PRIC295 interacts with nuclear receptors such as PPAR and functions as a transcription coactivator underin vitroconditions and may play an important role in mediating the effectsin vivoas a member of the PRIC complex with Med1 and Med24.

scholarly journals Friend of Prmt1, a Novel Chromatin Target of Protein Arginine Methyltransferases

2009 ◽  
Vol 30 (1) ◽  
pp. 260-272 ◽  
Author(s):  
Thamar Bryn van Dijk ◽  
Nynke Gillemans ◽  
Claudia Stein ◽  
Pavlos Fanis ◽  
Jeroen Demmers ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Unknown Function ◽  
Target Genes ◽  
Arginine Methylation ◽  
Critical Event ◽  
Protein Arginine Methyltransferases ◽  
Isolation And Characterization ◽  
Promoter Occupancy

ABSTRACT We describe the isolation and characterization of Friend of Prmt1 (Fop), a novel chromatin target of protein arginine methyltransferases. Human Fop is encoded by C1orf77, a gene of previously unknown function. We show that Fop is tightly associated with chromatin, and that it is modified by both asymmetric and symmetric arginine methylation in vivo. Furthermore, Fop plays an important role in the ligand-dependent activation of estrogen receptor target genes, including TFF1 (pS2). Fop depletion results in an almost complete block of estradiol-induced promoter occupancy by the estrogen receptor. Our data indicate that Fop recruitment to the promoter is an early critical event in the activation of estradiol-dependent transcription.

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