Antipeptide polyclonal antibodies specifically recognize each human thyroid hormone receptor isoform

Falcone, M

doi:10.1210/en.131.5.2419

Cited by 49 publications

(39 citation statements)

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“…3). Staining was both nuclear and cytoplasmic, as reported before (Falcone et al 1992, Zandieh et al 2002. Valves did not stain and thus gave an additional indication of the specificity of the reaction with the antisera (data not shown).…”

Section: Immunohistochemistry In the Adult Heartsupporting

confidence: 69%

Expression pattern and ontogenesis of thyroid hormone receptor isoforms in the mouse heart

Stoykov¹,

Zandieh-Doulabi²,

Moorman³

et al. 2006

Journal of Endocrinology

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Nuclear thyroid hormone (T 3 ) receptors (TR) play a critical role in mediating the effects of T 3 on development, differentiation and normal physiology of many organs. The heart is a major target organ of T 3 , and recent studies in knockout mice demonstrated distinct effects of the different TR isoforms on cardiac function, but the specific actions of TR isoforms and their specific localization in the heart remain unclear. We therefore studied the expression of TR 1, TR 2 and TR 1 isoforms in the mouse heart at different stages of development, using monoclonal antibodies against TR 1, TR 2 and TR 1. In order to identify distinct components of the embryonic heart, in situ hybridization for cardiac-specific markers was used with the expression pattern of sarcoplasmic reticulum calcium-ATPase 2a as a marker of myocardial structures, while the pattern of expression of connexin40 was used to indicate the developing chamber myocardium and peripheral ventricular conduction system. Here we show that in the ventricles of the adult heart the TR 1 isoform is confined to the cells that form the peripheral ventricular conduction system. TR 1, on the other hand, is present in working myocardium as well as in the peripheral ventricular conduction system. In the atria and in the proximal conduction system (sinoatrial node, atrioventricular node), TR 1 and TR 1 isoforms are coexpressed. We also found the heterogeneous expression of the TR 1, TR 2 and TR 1 isoforms in the developing mouse heart, which, in the case of the TR 1 isoform, gradually revealed a dynamic expression pattern. It was present in all cardiomyocytes at the early stages of cardiogenesis, but from embryonic day 11·5 and into adulthood, TR 1 demonstrated a gradual confinement to the peripheral ventricular conduction system (PVCS), suggesting a specific role of this isoform in the formation of PVCS. Detailed knowledge of the distribution of TR 1 and TR 1 in the heart is of importance for understanding not only their mechanism of action in the heart but also the design and (clinical) use of TR isoform-specific agonists and antagonists.

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Section: Immunohistochemistry In the Adult Heartsupporting

confidence: 69%

Expression pattern and ontogenesis of thyroid hormone receptor isoforms in the mouse heart

Stoykov¹,

Zandieh-Doulabi²,

Moorman³

et al. 2006

Journal of Endocrinology

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“…TRa1QF, TRa1QR, TRb1QF, TRb1QR, b-ActinQF, and bActinQR, were used in the quantitative study TR protein levels correlate with RNA expression To con®rm at the protein level the di erences in RNA expression found by using semi-quantitative RT ± PCR, we performed Western analysis of the cases where tumor and normal tissues were available, ®ve with normal RNA expression and patients #24 and #76 with altered expression. According to previous reports, a band of 48 kDa was detected using an antibody (a-144) against TRa1, while two di erent anti-TRb antibodies (b-62 and b-82) detected a band of 55 kDa (Falcone et al, 1992). The results were in good concordance with those obtained by semi-quantitative RT ± PCR: no changes in protein levels were detected in any of the ®ve patients with normal TR RNA expression, while lower expression of TRb1 but not TRa1 polypeptides was found in patient #24, and reduction in both TRa1 and TRb1 was clear in patient #76 (Figure 3).…”

Section: Tr Rna Expression Is Altered In a Subset Of Breast Tumorsmentioning

confidence: 71%

Expression of thyroid hormone receptor/erbA genes is altered in human breast cancer

et al. 2002

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The relation between thyroid status and diseases and cancer is unclear. No detailed analysis of thyroid hormone receptor (TR) expression in human breast cancer has been reported. We have analysed the expression and mutational status of the TRa1, encoded by the c-erbA proto-oncogene, TRb1 and TRb2 isoforms in 70 sporadic breast cancers. Alterations in the RNA level of TRb1, TRa1, or both were found in a number of patients. No expression of TRb2 RNA was detected. Western blotting analysis con®rmed the di erences in expression at the protein level in those cases where su cient tumor sample was available. Additionally, tumor-speci®c truncated TRb1 RNA was found in six patients. Strikingly, three transcripts shared the same breakpoint. Only one tumor carried the corresponding deletion at the genomic DNA level, suggesting that the remaining abnormal TRb1 transcripts are aberrant splicing products. Though no signi®cant correlation was found between TRb1 alteration and any clinical parameter, it showed a tendency to associate with early age of onset (550 years). Our results reveal speci®c alterations in the expression of TRb and TRa genes in a subset of breast cancer patients, suggesting that deregulation of thyroid hormone target genes may be involved in the generation of this neoplasia.

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“…We then examined the sensitivity to TH in two peripheral tissues, liver and heart, that express predominantly the TR␤ and TR␣ genes, respectively (15,(39)(40), † †). Studies were carried out under the conditions of TH deprivation and TH supplementation, according to a previously tested and standardized protocol (15,21,33).…”

Section: Discussionmentioning

confidence: 99%

Increased sensitivity to thyroid hormone in mice with complete deficiency of thyroid hormone receptor alpha

Macchia¹

2000

Proceedings of the National Academy of Sciences

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Only three of the four thyroid hormone receptor (TR) isoforms, ␣1, ␤1, and ␤2, bind thyroid hormone (TH) and are considered to be true TRs. TR␣2 binds to TH response elements on DNA, but its role in vivo is still unknown. We produced mice completely deficient in TR␣ (TR␣ o/o ) that maintain normal serum thyroid-stimulating hormone (TSH) concentration despite low serum thyroxine (T4), suggesting increased sensitivity to TH. We therefore examined the effects of TH (L-3,3 ,5-triiodothyronine, L-T3) given to TH-deprived and to intact TR␣ o/o mice. Controls were wild-type (WT) mice of the same strain and mice resistant to TH due to deficiency in TR␤ (TR␤ ؊/؊ ). In liver, T3 produced significantly greater responses in TR␣ o/o and smaller responses in TR␤ ؊/؊ as compared with WT mice. In contrast, cardiac responses to L-T3 were absent or reduced in TR␣ o/o , whereas they were similar in WT and TR␤ ؊/؊ mice, supporting the notion that TR␣1 is the dominant TH-dependent TR isoform in heart. 5-Triiodothyronine (L-T3) given to intact mice produced a greater suppression of serum T4 in TR␣ o/o than it did in WT mice and reduced by a greater amount the TSH response to TSH-releasing hormone. This is an in vivo demonstration that a TR deficiency can enhance sensitivity to TH. This effect is likely due to the abrogation of the constitutive ''silencing'' effect of TR␣2 in tissues expressing the TR␤ isoforms.T hyroid hormone (TH) action is mediated through specific nuclear TH receptors (TRs) functioning as ligand-dependent transcription factors that increase or decrease the expression of target genes (1-3). There are two TR genes. The TR␤ locus generates the ␤1 and ␤2 receptors by using two different promoters and alternative splicing. The TR␣ locus encodes TR␣1, a molecule containing 410 aa, and three proteins that do not bind the ligand, triiodothyronine (T 3 ) (4-7) (GenBank accession no. AI322342). TR␣2, which results from an alternative splicing of the TR␣ primary transcript, has 492 aa, the first 370 of which are identical to TR␣1. TR⌬␣1 and TR⌬␣2, molecules of approximately 154 and 237 aa, respectively, are generated from an internal promoter located in intron 7 of the TR␣ locus (6). The function of TR␣2, which has a wide tissue distribution (8), and that of TR⌬␣1 and TR⌬␣2, found mainly in brain, gut, and lung (6), are still unknown. However, all have been shown to inhibit ligand-dependent transactivation of TR␤ and TR␣1, a phenomenon termed the dominant negative effect (6, 9-11, ** ).The relative contribution of the two TR gene products in mediating TH responses is poorly understood because of the paucity of information regarding in vivo function. In vitro DNA binding studies and functional assays in transfected cells have generated conflicting results concerning the specific effect of TR isoforms in gene regulation (12, 13). Interpretation is complicated, however, because data are derived from artificial systems using the overexpression of chimeric gene constructs that may not be faithful models of events occurring in the...

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Antipeptide polyclonal antibodies specifically recognize each human thyroid hormone receptor isoform

Cited by 49 publications

References 0 publications

Expression pattern and ontogenesis of thyroid hormone receptor isoforms in the mouse heart

Expression pattern and ontogenesis of thyroid hormone receptor isoforms in the mouse heart

Expression of thyroid hormone receptor/erbA genes is altered in human breast cancer

Increased sensitivity to thyroid hormone in mice with complete deficiency of thyroid hormone receptor alpha

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