Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thyroid hormone response elements (T3REs) have been identified in a variety of promoters including those directing expression of rat GH (rGH), alpha-myosin heavy chain (rMHC), and malic enzyme (rME). A detailed biochemical and genetic analysis of the rGH element has shown that it consists of three hexamers related to the consensus [(A/G)GGT(C/A)A]. We have extended this analysis to the rMHC and rME elements. Binding of highly purified thyroid hormone receptor (T3R) to T3REs was determined using the gel shift assay, and thyroid hormone (T3) induction was measured in transient tranfections. We show that the wild type version of each of the three elements binds T3R dimers cooperatively. Mutational analysis of the rMHC and rME elements identified domains important for binding T3R dimers and allowed a direct determination of the relationship between T3R binding and function. In each element two hexamers are required for dimer binding, and mutations that interfere with dimer formation significantly reduce T3 induction. Similar to the rGH element, the rMHC T3RE contains three hexameric domains arranged as a direct repeat followed by an inverted copy, although the third domain is weaker than in rGH. All three are required for full function and T3R binding. The rME T3RE is a two-hexamer direct repeat T3RE, which also binds T3R monomer and dimer. Across a series of mutant elements, there was a strong correlation between dimer binding in vitro and function in vivo for rMHC (r = 0.99, P less than 0.01) and rME (r = 0.67, P less than 0.05) T3REs. Our results demonstrate a similar pattern of T3R dimer binding to a diverse array of hexameric sequences and arrangements in three wild type T3REs. Addition of nuclear protein enhanced T3R binding but did not alter the specificity of binding to wild type or mutant elements. Binding of purified T3R to T3REs was highly correlated with function, both with and without the addition of nuclear protein. T3R dimer formation is the common feature which defines the capacity of these elements to confer T3 induction.
Mol Endocrinol 1992 Apr
PMID:Capacity for cooperative binding of thyroid hormone (T3) receptor dimers defines wild type T3 response elements. 158 20

The epidermal growth factor (EGF) receptor (EGFR) promoter is negatively regulated by thyroid hormone and retinoic acid. This regulation can be mapped to a 36-basepair GC-rich region of the promoter (EGFR P/E) that functions autonomously as a promoter and an enhancer when placed in front of the thymidine kinase gene TATA element. Direct high affinity binding of the thyroid hormone receptor (T3R) to this element requires a nuclear protein. Through ion exchange chromatography and gel filtration of HeLa nuclear extract, this activity was identified as a protein of approximately 67 kilodaltons. This protein did not bind to DNA alone, but greatly augmented T3R binding to the EGFR P/E sequence in gel mobility shift and DNA precipitation assays. When combined with the T3R auxillary protein (TRAP), the T3R migrated as a larger complex on the DNA. Chemical cross-linking identified this complex as a heterodimer between T3R and TRAP. T3R-TRAP binds to a 7-basepair site in the EGFR P/E (GGGACTC) that has weak homology to a consensus thyroid response element half-site. Thus, on this element, T3R-TRAP heterodimers contact the DNA primarily on a single site that comprises an inhibitory thyroid response element.
Mol Endocrinol 1992 Apr
PMID:A nuclear protein is required for thyroid hormone receptor binding to an inhibitory half-site in the epidermal growth factor receptor promoter. 158 25

The rat GH (rGH) gene is expressed in the pituitary in a highly tissue-specific manner. A pituitary-specific transcription factor, Pit-1 (or GHF-1), and other, more tissue-general factors, including the thyroid hormone receptor (T3R), are important for regulating rGH promoter activity. The relative roles of Pit-1, T3R, and protein kinases in the activation of the rGH promoter were studied. Each component was supplied individually or in combination with the others to human monocyte U937 cells. The transfected rGH promoter was inactive in these cells even when it was cotransfected with either Pit-1 or T3R expression vectors. The rGH promoter carried in a truncated pUC vector could be activated by expression of the T3R if the cells were cultured with inducers of protein kinase-A (forskolin) and protein kinase-C [phorbol 12-myristate 13-acetate (PMA)] activity. By contrast, the PMA- and forskolin-dependent activation of the rGH promoter by Pit-1 expression was comparatively insignificant unless 1) the sequences deleted from the pUC vector (including a putative site for the transcription factor AP1) were restored to the plasmid carrying the rGH promoter; or 2) the T3R was coexpressed, which led to a marked synergistic response. These results indicate the relative inactivity of Pit-1 in isolation from other factors. Activation by forskolin and PMA did not require de novo protein synthesis. The synergistic activation by Pit-1 and the T3R was enhanced, but was not dependent upon, thyroid hormone (T3). The T3-dependent effect operated predominately through a thyroid hormone response element located up-stream of the two Pit-1-binding sites within the rGH promoter, whereas the T3-independent effect did not require any of the known T3R-binding sites on the rGH promoter. These results suggest a role for the more tissue-general T3R and protein kinases in the activation of the rGH promoter. They demonstrate the synergistic interplay between the T3R and Pit-1, underscore the dependence of Pit-1 action on other transcription factors, and implicate Pit-1 as a cofactor, rather than the dominant factor, influencing the tissue-specific expression of the rGH promoter.
Mol Endocrinol 1992 Apr
PMID:Synergistic activation of the rat growth hormone promoter by Pit-1 and the thyroid hormone receptor. 158 27

Mutations of the thyroid hormone receptor (TR) beta 1 gene have recently been detected in several unrelated families with generalized resistance to thyroid hormone (GRTH). We now report a novel point mutation in the TR beta 1 gene in a case of a Korean-Japanese kindred. The intracellular localization and the amount of TR proteins were considered to be normal by the immunocytochemical study of cultured skin fibroblasts from the patients using anti-T3 receptor antibody. The cDNA of the T3-binding domain of the TR beta 1 gene, synthesized from the total RNA of the patients' fibroblasts, was amplified by the polymerase chain reaction, and was sequenced. A point mutation, A to G, in one allele at 1612 resulting in an amino acid substitution from lysine 438 to glutamic acid was detected. The same mutation was identified in one allele in each of the affected members. In vitro translation products of the mutant TR beta 1 gene showed decreased T3-binding activity. These data suggest that a TR mutation is predominantly responsible for GRTH, irrespective of ethnic background.
Mol Cell Endocrinol 1992 Apr
PMID:A point mutation of the T3 receptor beta 1 gene in a kindred of generalized resistance to thyroid hormone. 158 88

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.
Mol Cell Endocrinol 1992 Apr
PMID:Expression and function of a human thyroid hormone receptor-derived DNA-binding domain protein. 158 92

In thyroid hormone-depleted rats, the rate of transcription of the growth hormone (GH) gene in the anterior pituitary gland is lower than the rate in euthyroid controls, and there is a corresponding reduction in the abundance of the GH mRNA. Concomitantly, the poly(A) tail of the GH mRNA increases in length. Examination of nuclear RNA from anterior pituitary glands of control and thyroid hormone-depleted rats revealed no difference in the length of pre-mRNAs containing the first and last introns of the GH gene. However, mature nuclear GH RNA is differentially polyadenylated in euthyroid and hypothyroid animals. We suggest that the extent of polyadenylation of the GH transcript is regulated in the cell nucleus concomitant with or subsequent to the splicing of the pre-mRNA. Experiments with anterior pituitary gland explant cultures demonstrated that the GH mRNA from thyroid hormone-depleted rats is more stable than its euthyroid counterpart and that the poly(A) tail may contribute to the differential stability of free GH ribonucleoproteins.
Mol Cell Biol 1992 Jun
PMID:Posttranscriptional regulation of rat growth hormone gene expression: increased message stability and nuclear polyadenylation accompany thyroid hormone depletion. 158 60

Carboxypeptidase-H (CPH) is a metallocarboxypeptidase implicated in the processing of peptide hormones. Consistent with such a role, the gene for CPH is expressed in cells that secrete regulatory peptides, such as those of the brain and endocrine tissues. In the rat brain, CPH is transcribed from a single transcriptional start site associated with the initiator-type element first described in the gene encoding lymphocyte-specific terminal deoxynucleotidyltransferase. We have used a combination of Northern blot analysis and S1 nuclease protection mapping to describe the expression and transcription initiation pattern of the gene for CPH in the peripheral tissues and brain regions of the normal rat. The single transcriptional start site is used in all tissues examined, except the pituitary, where two additional specific initiation sites are found. The expression of the CPH gene is up-regulated in the anterior pituitary gland as a consequence of systemic thyroid hormone depletion, and this increase is associated with a preferential utilization of the novel upstream transcriptional initiation sites. Thus, the use of different major transcriptional initiation sites of the CPH gene in the pituitary gland is subject to differential direct or indirect thyroid hormone regulation.
Mol Endocrinol 1992 May
PMID:Pituitary-specific transcriptional initiation sites of the rat carboxypeptidase-H gene and the influence of thyroid hormone status. 160 81

A tumor appeared on the back of a transgenic mouse carrying the SV40 T-antigen under control of a mouse major urinary protein promoter. High levels of mRNA for the mitochondrial uncoupling protein (UCP) indicated that the tumor was a hibernoma. The tumor has been established as a transplantable tumor line in nude (nu/nu) mice and used as a source of cells to develop a tissue culture system for analyzing brown fat development and differentiation. Ucp expression in tumor cells cultured in Dulbecco's modified Eagle's medium and 10% fetal calf serum was virtually undetectable. Addition of 10(-7) M norepinephrine resulted in approximately a 30-fold induction of Ucp mRNA within 4 h. The induction by norepinephrine was independent of cell density and also independent of thyroid hormone and insulin during the first 5 days in culture. However, in order to maintain the inducibility of Ucp during prolonged culture periods, it was necessary to supplement the medium with insulin. In contrast to Ucp, the expression of Gdc-1, which encodes the cytoplasmic glycerol-3-phosphate dehydrogenase and which is also induced in brown fat by cold exposure, was repressed by norepinephrine and induced by the addition of insulin. Characterization of the adrenergic receptors required for Ucp induction with agonists and antagonists indicated that beta 1 receptors are predominantly utilized; there is no evidence for utilization of beta 3 and alpha 1 receptors for Ucp induction.
Mol Endocrinol 1992 May
PMID:Adrenergic regulation of the mitochondrial uncoupling protein gene in brown fat tumor cells. 160 85

We have determined the nucleotide sequences of the variable regions of H and L chains of a monoclonal antibody 98QQ that interacts with the thyroid hormone triiodo-L- thyronine with high affinity. Analysis of the nucleotide sequence of the light chain V region of 98QQ revealed that the VL sequence is 99% identical to Balb/c germline Vk 21-E sequence. That is an interesting finding with this high affinity anti-T3 antibody, since occurence of predominantly germline variable region sequences is observed in some autoantibodies to self antigens but not usually in high affinity IgG antibodies. The sequence analysis also revealed that the heavy chain variable region sequence of 98QQ is similar to a V region of an anti-DNA antibody (MRL DNA 22). Thus the sequence analysis of our anti-T3 mAb 98QQ has revealed some features of autoantibodies to self antigens.
Mol Immunol
PMID:Sequences of variable regions of a monoclonal antibody specific to the thyroid hormone, triiodo-L-thyronine. 163 58

Putative thyroid hormone (TH) nuclear receptors have been detected in several tissues of Rana catesbeiana tadpoles. T3 receptor number (sites per nucleus) in red blood cells (RBCs) and tail increases substantially just before metamorphic climax or in response to exogenous TH; in contrast, receptor number in liver remains relatively constant. TH receptors in mammals and birds are thought to be encoded by a c-erbA gene. In the present study, two c-erbA cDNAs, one prepared from Xenopus laevis oocytes (XenTR alpha 1) and one prepared from Rana catesbeiana tail (RC12), were used to examine the c-erbA-related mRNA species in Rana catesbeiana tissues and determine their role in the TH induction of tadpole RBC receptor number. XenTR alpha 1 encodes a protein with T3-binding properties typical of TH receptors. RC12 is almost 99% homologous with XenTR alpha 1 at the amino acid level and contains all of the putative T3-binding region and most of the DNA-binding region. Using either cDNA as a probe, it was found that two major species of c-erbA-related mRNA species (2.6 and 4.0 kilobases) were clearly evident in tadpole RBCs, tail, and liver. A third, more diffuse band (approximately 5.0 kilobases) was observed in RBC and tail. In RBCs, but not in liver, the combined level of c-erbA-related mRNA species was increased during spontaneous metamorphosis or after administration of TH. Furthermore, the TH-induced increase in both c-erbA-related mRNA species and receptor number in RBCs was prevented if actinomycin-D was administered with TH.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Endocrinol 1991 Feb
PMID:Regulation of c-erbA-alpha messenger RNA species in tadpole erythrocytes by thyroid hormone. 164 54


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