Altered Intracellular Trafficking of Mutant Thyroid Hormone Receptors in Resistance to Thyroid Hormone Syndrome

RAP1 is an essential sequence-specific DNA-binding protein in Saccharomyces cerevisiae whose binding sites are found in a large number of promoters, where they function as upstream activation sites, and at the silencer elements of the HMR and HML mating-type loci, where they are important for repression. We have examined the involvement of specific regions of the RAP1 protein in both repression and activation of transcription by studying the properties of a series of hybrid proteins containing RAP1 sequences fused to the DNA-binding domain of the yeast protein GAL4 (amino acids 1 to 147). GAL4 DNA-binding domain/RAP1 hybrids containing only the carboxy-terminal third of the RAP1 protein (which lacks the RAP1 DNA-binding domain) function as transcriptional activators of a reporter gene containing upstream GAL4 binding sites. Expression of some hybrids from the strong ADH1 promoter on multicopy plasmids has a dominant negative effect on silencers, leading to either partial or complete derepression of normally silenced genes. The GAL4/RAP1 hybrids have different effects on wild-type and several mutated but functional silencers. Silencers lacking either an autonomously replicating sequence consensus element or the RAP1 binding site are strongly derepressed, whereas the wild-type silencer or a silencer containing a deletion of the binding site for another silencer-binding protein, ABF1, are only weakly affected by hybrid expression. By examining a series of GAL4 DNA-binding domain/RAP1 hybrids, we have mapped the transcriptional activation and derepression functions to specific parts of the RAP1 carboxy terminus.(ABSTRACT TRUNCATED AT 250 WORDS)

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Dissection of a carboxy-terminal region of the yeast regulatory protein RAP1 with effects on both transcriptional activation and silencing.

Molecular and Cellular Biology ◽

10.1128/mcb.12.3.1209 ◽

1992 ◽

Vol 12 (3) ◽

pp. 1209-1217 ◽

Cited By ~ 49

Author(s):

C F Hardy ◽

D Balderes ◽

D Shore

Keyword(s):

Dna Binding ◽

Binding Site ◽

Transcriptional Activation ◽

Binding Sites ◽

Binding Protein ◽

Binding Domain ◽

Dominant Negative Effect ◽

Dna Binding Domain ◽

Wild Type ◽

Carboxy Terminal

RAP1 is an essential sequence-specific DNA-binding protein in Saccharomyces cerevisiae whose binding sites are found in a large number of promoters, where they function as upstream activation sites, and at the silencer elements of the HMR and HML mating-type loci, where they are important for repression. We have examined the involvement of specific regions of the RAP1 protein in both repression and activation of transcription by studying the properties of a series of hybrid proteins containing RAP1 sequences fused to the DNA-binding domain of the yeast protein GAL4 (amino acids 1 to 147). GAL4 DNA-binding domain/RAP1 hybrids containing only the carboxy-terminal third of the RAP1 protein (which lacks the RAP1 DNA-binding domain) function as transcriptional activators of a reporter gene containing upstream GAL4 binding sites. Expression of some hybrids from the strong ADH1 promoter on multicopy plasmids has a dominant negative effect on silencers, leading to either partial or complete derepression of normally silenced genes. The GAL4/RAP1 hybrids have different effects on wild-type and several mutated but functional silencers. Silencers lacking either an autonomously replicating sequence consensus element or the RAP1 binding site are strongly derepressed, whereas the wild-type silencer or a silencer containing a deletion of the binding site for another silencer-binding protein, ABF1, are only weakly affected by hybrid expression. By examining a series of GAL4 DNA-binding domain/RAP1 hybrids, we have mapped the transcriptional activation and derepression functions to specific parts of the RAP1 carboxy terminus.(ABSTRACT TRUNCATED AT 250 WORDS)

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Characterization of the DNA-Binding and Dimerization Properties of the Nuclear Orphan Receptor Germ Cell Nuclear Factor

Molecular and Cellular Biology ◽

10.1128/mcb.19.1.690 ◽

1999 ◽

Vol 19 (1) ◽

pp. 690-703 ◽

Cited By ~ 35

Author(s):

Holger Greschik ◽

Jean-Marie Wurtz ◽

Philip Hublitz ◽

Fabian Köhler ◽

Dino Moras ◽

...

Keyword(s):

Dna Binding ◽

Germ Cell ◽

Nuclear Receptor ◽

Target Gene ◽

Binding Domain ◽

Orphan Receptor ◽

Nuclear Factor ◽

Binding Behavior ◽

Helix 12 ◽

Germ Cell Nuclear Factor

ABSTRACT The orphan receptor germ cell nuclear factor (GCNF) is a member of the superfamily of nuclear receptors. During development, GCNF exhibits a restricted brain-specific expression pattern, whereas GCNF expression in the adult is germ cell specific. Therefore, the receptor may participate in the regulation of neurogenesis and reproductive functions. No natural GCNF target gene has yet been identified, but recent data demonstrate specific and high-affinity binding of GCNF either to the direct repeat DNA element AGGTCAAGGTCA (DR0) or to extended half-sites, such as TCAAGGTCA. In this study, we show that murine GCNF (mGCNF) can bind as a homodimer to extended half-sites, thus describing a novel property within the nuclear receptor superfamily. Homodimeric binding to extended half-sites requires the presence of a dimerization function within the mGCNF DNA-binding domain (DBD) and a novel dimerization surface encompassing the putative helix 3 and the helix 12 region of the mGCNF ligand-binding domain (LBD). In addition, the mGCNF LBD has the potential to adopt different conformations with distinct dimerization properties. The helix 12 region of the mGCNF LBD not only regulates the switch between these dimerization conformations but also dictates the DNA-binding behavior and transcriptional properties of the different dimerization conformations. In summary, our findings describe unique DNA-binding and dimerization properties of a nuclear receptor and suggest a novel mechanism that allows mGCNF to modulate target gene activity.

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A direct and widespread role for the nuclear receptor EcR in mediating the response to ecdysone in Drosophila

10.1101/517458 ◽

2019 ◽

Cited By ~ 2

Author(s):

Christopher M. Uyehara ◽

Daniel J. McKay

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Dna Binding ◽

Nuclear Receptor ◽

Binding Sites ◽

Target Genes ◽

Transcriptional Responses ◽

Developmental Transitions ◽

The Impact

ABSTRACTThe ecdysone pathway was amongst the first experimental systems employed to study the impact of steroid hormones on the genome. In Drosophila and other insects, ecdysone coordinates developmental transitions, including wholesale transformation of the larva into the adult during metamorphosis. Like other hormones, ecdysone controls gene expression through a nuclear receptor, which functions as a ligand-dependent transcription factor. Although it is clear that ecdysone elicits distinct transcriptional responses within its different target tissues, the role of its receptor, EcR, in regulating target gene expression is incompletely understood. In particular, EcR initiates a cascade of transcription factor expression in response to ecdysone, making it unclear which ecdysone-responsive genes are direct EcR targets. Here, we use the larval-to-prepupal transition of developing wings to examine the role of EcR in gene regulation. Genome-wide DNA binding profiles reveal that EcR exhibits widespread binding across the genome, including at many canonical ecdysone-response genes. However, the majority of its binding sites reside at genes with wing-specific functions. We also find that EcR binding is temporally dynamic, with thousands of binding sites changing over time. RNA-seq reveals that EcR acts as both a temporal gate to block precocious entry to the next developmental stage as well as a temporal trigger to promote the subsequent program. Finally, transgenic reporter analysis indicates that EcR regulates not only temporal changes in target enhancer activity but also spatial patterns. Together, these studies define EcR as a multipurpose, direct regulator of gene expression, greatly expanding its role in coordinating developmental transitions.SIGNIFICANCENuclear receptors (NRs) are sequence-specific DNA binding proteins that act as intracellular receptors for small molecules such as hormones. Prior work has shown that NRs function as ligand-dependent switches that initiate a cascade of gene expression changes. The extent to which NRs function as direct regulators of downstream genes in these hierarchies remains incompletely understood. Here, we study the role of the NR EcR in metamorphosis of the Drosophila wing. We find that EcR directly regulates many genes at the top of the hierarchy as well as at downstream genes. Further, we find that EcR binds distinct sets of target genes at different developmental times. This work helps inform how hormones elicit tissue- and temporal-specific responses in target tissues.

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DNA-binding and transcriptional regulatory properties of hepatic leukemia factor (HLF) and the t(17;19) acute lymphoblastic leukemia chimera E2A-HLF

Molecular and Cellular Biology ◽

10.1128/mcb.14.9.5986-5996.1994 ◽

1994 ◽

Vol 14 (9) ◽

pp. 5986-5996

Author(s):

S P Hunger ◽

R Brown ◽

M L Cleary

Keyword(s):

Dna Binding ◽

Binding Site ◽

Dna Sequences ◽

Transcriptional Activation ◽

Binding Sites ◽

Lymphoblastic Leukemia ◽

Consensus Sequence ◽

Reporter Genes ◽

Wild Type ◽

Basic Leucine Zipper

The t(17;19) translocation in acute lymphoblastic leukemias results in creation of E2A-hepatic leukemia factor (HLF) chimeric proteins that contain the DNA-binding and protein dimerization domains of the basic leucine zipper (bZIP) protein HLF fused to a portion of E2A proteins with transcriptional activation properties. An in vitro binding site selection procedure was used to determine DNA sequences preferentially bound by wild-type HLF and chimeric E2A-HLF proteins isolated from various t(17;19)-bearing leukemias. All were found to selectively bind the consensus sequence 5'-GTTACGTAAT-3' with high affinity. Wild-type and chimeric HLF proteins also bound closely related sites identified previously for bZIP proteins of both the proline- and acidic amino acid-rich (PAR) and C/EBP subfamilies; however, E2A-HLF proteins were significantly less tolerant of certain deviations from the HLF consensus binding site. These differences were directly attributable to loss of an HLF ancillary DNA-binding domain in all E2A-HLF chimeras and were further exacerbated by a zipper mutation in one isolate. Both wild-type and chimeric HLF proteins displayed transcriptional activator properties in lymphoid and nonlymphoid cells on reporter genes containing HLF or C/EBP consensus binding sites. But on reporter genes with nonoptimal binding sites, their transcriptional properties diverged and E2A-HLF competitively inhibited activation by wild-type PAR proteins. These findings establish a spectrum of binding site-specific transcriptional properties for E2A-HLF which may preferentially activate expression of select subordinate genes as a homodimer and potentially antagonize expression of others through heteromeric interactions.

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An Inhibitory Region of the DNA-Binding Domain of Thyroid Hormone Receptor Blocks Hormone-Dependent Transactivation

Molecular Endocrinology ◽

10.1210/mend.12.1.0046 ◽

1998 ◽

Vol 12 (1) ◽

pp. 34-44 ◽

Cited By ~ 3

Author(s):

Ying Liu ◽

Akira Takeshita ◽

Takashi Nagaya ◽

Aria Baniahmad ◽

William W. Chin ◽

...

Keyword(s):

Thyroid Hormone ◽

Dna Binding ◽

Ligand Binding ◽

Transcriptional Activation ◽

Thyroid Hormone Receptor ◽

Binding Domain ◽

Dna Binding Domain ◽

Chimeric Receptor ◽

Receptor System ◽

Inhibitory Region

Abstract We have employed a chimeric receptor system in which we cotransfected yeast GAL4 DNA-binding domain/retinoid X receptor β ligand-binding domain chimeric receptor (GAL4RXR), thyroid hormone receptor-β (TRβ), and upstream activating sequence-reporter plasmids into CV-1 cells to study repression, derepression, and transcriptional activation. In the absence of T3, unliganded TR repressed transcription to 20% of basal level, and in the presence of T3, liganded TRβ derepressed transcription to basal level. Using this system and a battery of TRβ mutants, we found that TRβ/RXR heterodimer formation is necessary and sufficient for basal repression and derepression in this system. Additionally, an AF-2 domain mutant (E457A) mediated basal repression but not derepression, suggesting that interaction with a putative coactivator at this site may be critical for derepression. Interestingly, a mutant containing only the TRβ ligand binding domain (LBD) not only mediated derepression, but also stimulated transcriptional activation 10-fold higher than basal level. Studies using deletion and domain swap mutants localized an inhibitory region to the TRβ DNA-binding domain. Titration studies further suggested that allosteric changes promoting interaction with coactivators may account for enhanced transcriptional activity by LBD. In summary, our findings suggest that TR heterodimer formation with RXR is important for repression and derepression, and coactivator interaction with the AF-2 domain may be needed for derepression in this chimeric system. Additionally, there may be an inhibitory region in the DNA-binding domain, which reduces TR interaction with coactivators, and prevents full-length wild-type TRβ from achieving transcriptional activation above basal level in this chimeric receptor system.

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DNA-binding and transcriptional regulatory properties of hepatic leukemia factor (HLF) and the t(17;19) acute lymphoblastic leukemia chimera E2A-HLF.

Molecular and Cellular Biology ◽

10.1128/mcb.14.9.5986 ◽

1994 ◽

Vol 14 (9) ◽

pp. 5986-5996 ◽

Cited By ~ 39

Author(s):

S P Hunger ◽

R Brown ◽

M L Cleary

Keyword(s):

Dna Binding ◽

Binding Site ◽

Dna Sequences ◽

Transcriptional Activation ◽

Binding Sites ◽

Lymphoblastic Leukemia ◽

Consensus Sequence ◽

Reporter Genes ◽

Wild Type ◽

Basic Leucine Zipper

The t(17;19) translocation in acute lymphoblastic leukemias results in creation of E2A-hepatic leukemia factor (HLF) chimeric proteins that contain the DNA-binding and protein dimerization domains of the basic leucine zipper (bZIP) protein HLF fused to a portion of E2A proteins with transcriptional activation properties. An in vitro binding site selection procedure was used to determine DNA sequences preferentially bound by wild-type HLF and chimeric E2A-HLF proteins isolated from various t(17;19)-bearing leukemias. All were found to selectively bind the consensus sequence 5'-GTTACGTAAT-3' with high affinity. Wild-type and chimeric HLF proteins also bound closely related sites identified previously for bZIP proteins of both the proline- and acidic amino acid-rich (PAR) and C/EBP subfamilies; however, E2A-HLF proteins were significantly less tolerant of certain deviations from the HLF consensus binding site. These differences were directly attributable to loss of an HLF ancillary DNA-binding domain in all E2A-HLF chimeras and were further exacerbated by a zipper mutation in one isolate. Both wild-type and chimeric HLF proteins displayed transcriptional activator properties in lymphoid and nonlymphoid cells on reporter genes containing HLF or C/EBP consensus binding sites. But on reporter genes with nonoptimal binding sites, their transcriptional properties diverged and E2A-HLF competitively inhibited activation by wild-type PAR proteins. These findings establish a spectrum of binding site-specific transcriptional properties for E2A-HLF which may preferentially activate expression of select subordinate genes as a homodimer and potentially antagonize expression of others through heteromeric interactions.

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A mutant androgen receptor from patients with Reifenstein syndrome: identification of the function of a conserved alanine residue in the D box of steroid receptors

Molecular and Cellular Biology ◽

10.1128/mcb.13.12.7850-7858.1993 ◽

1993 ◽

Vol 13 (12) ◽

pp. 7850-7858

Author(s):

F Kaspar ◽

H Klocker ◽

A Denninger ◽

A C Cato

Keyword(s):

Androgen Receptor ◽

Dna Binding ◽

Steroid Receptors ◽

Regulatory Elements ◽

Binding Domain ◽

Dna Binding Domain ◽

Wild Type ◽

Binding Studies ◽

Mutant Receptor ◽

Alanine Residue

Reifenstein syndrome is an eponymic term that describes partial androgen-insensitive disorders. Androgen receptor isolated from five patients with this syndrome contains a specific mutation in the DNA binding domain of the receptor. This mutation converts an alanine to a threonine at position 596 next to the zinc catenation site at the second finger. The threonine 596 mutant receptor mediated normal androgen response at promoters with closely positioned multiple regulatory elements for the androgen receptor and other transcription factors. Promoters with single isolated androgen response elements were not transactivated by the mutant receptor. In in vitro receptor-DNA binding studies, interaction with DNA by the mutant receptor was achieved only in the presence of an anti-androgen receptor antibody. Exchanging alanine 596 in the wild-type androgen receptor with serine or valine produced mutants with properties indistinguishable from those of the naturally occurring threonine 596 mutant receptor. These results indicate that an alanine residue at position 596 contributes important structural and functional activities to the androgen receptor. In the androgen receptor from the patients with Reifenstein syndrome, in which this alanine is converted to a threonine, wild-type receptor properties can be restored by exchanging an additional threonine at position 602 to an alanine. An alanine residue at position 596 or 602 in the DNA binding domain of the androgen receptor is therefore important for the full function of this receptor. In all steroid receptors that bind the core sequence AGAACANNNTGTTCT, an alanine residue is also present at a position equivalent to alanine 596 in the androgen receptor.

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SAT-434 Phenotype and Genotype Analysis of Patients with Resistance to Thyroid Hormone β: A Single-Center Experience

Journal of the Endocrine Society ◽

10.1210/jendso/bvaa046.873 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

Author(s):

Karn Wejaphikul ◽

Prapai Dejkhamron ◽

Stefan Groeneweg ◽

W Edward Visser ◽

Kevalee Unachak ◽

...

Keyword(s):

Thyroid Hormone ◽

Mutation Analysis ◽

Novel Mutation ◽

Family Members ◽

Antithyroid Drugs ◽

Thyroid Function Tests ◽

Resistance To Thyroid Hormone ◽

The Mean ◽

The Impact

Abstract Introduction Resistance to thyroid hormone β (RTHβ) is caused by mutations in THRB, the gene that encodes thyroid hormone receptor β. The clinical phenotype is variable and may include goiter, tachycardia, and learning disability with or without hyperactive behavior. The biochemical hallmark of RTHβ is elevated T4 and T3 with non-suppressed TSH concentrations. We here describe the phenotype and genotype of three Thai patients diagnosed with RTHβ in a pediatric referral center. Patients had previously been misdiagnosed and inappropriately treated with antithyroid drugs (ATDs). Methods Clinical features and thyroid function tests (TFTs) of three unrelated RTHβ patients were retrospectively reviewed. Genomic DNA of the RTHβ patients and affected family members was amplified for exon 7-10 of the THRB gene and sequenced to identify mutation by Sanger sequencing. The impact of the p.L341V novel mutation on the affinity for T3 and T3-induced transcriptional activity was previously determined in vitro. Results Three female patients were diagnosed with RTHβ. All of them had been misdiagnosed with hyperthyroidism and treated with ATDs prior to referral. The mean age at diagnosis was 8 years. The main presenting symptoms were diffuse goiter and tachycardia. The mean duration of ATD treatment was 3 years. During the treatment, patients had fluctuating thyroid hormone and increased TSH levels. An older sister and mother of one patient also had similar TFTs abnormalities, for which the mother had undergone a subtotal thyroidectomy. RTHβ was diagnosed based on the high FT3 and FT4 with normal (non-suppressed) TSH concentrations and confirmed by mutation analysis. Anti-thyroid peroxidase, anti-thyroglobulin, and TSH receptor antibody (TRAb) were negative, excluding autoimmune thyroid disease. Heterozygous missense mutations of the THRB gene were identified in all patients and affected family members. Two mutations had been previously reported (p.R243W and p.L456F), and one mutation was novel (p.L341V). In vitro studies confirmed an important role of Leu341 in T3 binding of the TRβ and functional impairment of the p.L341V novel mutation and were reported separately. According to available literature, only nine Thai RTHβ patients (in three families) carrying three different mutations (p.G251V, p.M313T, and p.A317T) had been previously reported. Goiter was the most common clinical finding, and almost all patients had a history of receiving unnecessary treatment with ATDs. Conclusion We report a series of RTHβ patients carrying THRB gene mutations, including one novel mutation (p.L341V). Clinicians should be alert that RTHβ can be found in patients with goiter and tachycardia. Elevated T4 and T3 with non-suppressed TSH concentration is the main diagnostic clue for this disease. Mutation analysis allows definitive diagnosis of RTHβ and may help to avoid potential misdiagnosis and improper treatment.

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