{"gene":"THRA","run_date":"2026-06-10T10:51:55","timeline":{"discoveries":[{"year":1989,"finding":"TRα1 (c-erbA alpha 1) functions as a ligand-dependent transcriptional activator of thyroid hormone-responsive genes, while the alternatively spliced variant TRα2 (c-erbA alpha 2) does not bind T3 but inhibits T3-dependent gene induction mediated by TRα1 or TRβ, establishing dominant-negative antagonism through alternative splicing of the same locus.","method":"Transient transfection of T3-responsive reporter genes in mammalian cells; in vitro translation and ligand-binding assays","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — multiple independent labs (Koenig et al. PMID:2537467; Lazar et al. PMID:2903438; Lazar et al. PMID:2554288) replicated using in vitro binding, reporter assays, and mutagenesis","pmids":["2537467","2903438","2554288"],"is_preprint":false},{"year":1989,"finding":"The v-erbA oncogene protein acts as a constitutive transcriptional repressor of thyroid hormone-responsive promoters and, when co-expressed with c-erbA/TRα, blocks T3-dependent transcriptional activation, establishing v-erbA as a dominant-negative oncogene that antagonizes its cellular homolog.","method":"Co-transfection of v-erbA and c-erbA expression vectors with T3-responsive reporter genes in cell lines; functional transcriptional assays","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — replicated across multiple labs using reporter assays, chimeric protein analysis, and erythroid differentiation assays (PMID:2733791, PMID:1972036, PMID:1682217)","pmids":["2733791","1972036","1682217"],"is_preprint":false},{"year":1988,"finding":"The hormone-binding domain of c-erbA/TRα resides in the carboxy-terminal half of the protein; multiple mutations in this region of v-erbA cooperate to abolish T3 binding, and the ligand-binding domain is positionally analogous to that of steroid receptors.","method":"Chimeric v-erbA/c-erbA protein analysis; ligand-binding assays of in vitro translated deletion and chimeric mutants","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with systematic mutagenesis of chimeras; replicated by multiple deletion studies (PMID:3359993, PMID:2464752)","pmids":["3359993","2464752"],"is_preprint":false},{"year":1988,"finding":"c-erbA/TRα protein (p46c-erbA) is phosphorylated on serine residues in its amino-terminal domain; one site (Ser28/Ser29) is shared with v-erbA and phosphorylation is enhanced 10-fold by activators of PKC or PKA; cAMP-dependent protein kinase directly phosphorylates both proteins in vitro at this site.","method":"In vivo metabolic labeling, tryptic phosphopeptide mapping, in vitro kinase assays with purified cAMP-dependent protein kinase","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro kinase reconstitution plus in vivo phosphopeptide mapping, two orthogonal methods in one study (PMID:2903825)","pmids":["2903825"],"is_preprint":false},{"year":1989,"finding":"c-erbA/TRα is phosphorylated at Ser12 in its amino-terminal domain by casein kinase II; the site contains an acidic context matching CK2 consensus; purified CK2 phosphorylates c-erbA at the same site in vitro; Ser12→Ala mutation abolishes CK2 phosphorylation in vitro.","method":"In vitro phosphorylation with purified casein kinase II; site-directed mutagenesis (Ser12→Ala); two-dimensional phosphopeptide mapping","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with mutagenesis and 2D peptide mapping in a single focused study (PMID:2552374)","pmids":["2552374"],"is_preprint":false},{"year":1990,"finding":"Phosphorylation of Ser-16/17 in the v-erbA-encoded domain of the gag/v-erbA fusion protein is required for its oncogenic function: Ser→Ala substitutions at these positions abolish phosphorylation, block inhibition of erythroid differentiation, and prevent suppression of erythrocyte-specific genes (band 3, CAII), while Ser→Thr substitution preserves basal but not PKA/PKC-enhanced phosphorylation and gives partial activity.","method":"Site-directed mutagenesis of Ser-16/17; retroviral expression in ts-v-erbB or ts-v-sea erythroblasts; in vivo and in vitro phosphorylation analysis; differentiation and gene expression assays","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 1 / Strong — systematic mutagenesis with multiple orthogonal readouts (phosphorylation, differentiation, gene expression) in one rigorous study (PMID:1979040)","pmids":["1979040"],"is_preprint":false},{"year":1990,"finding":"A conserved 9-amino-acid sequence at the extreme C-terminus of c-ErbA alpha (deleted in v-ErbA) is essential for T3-dependent transcriptional activation, AP-1 transcriptional interference, and induction of erythroid differentiation; single, double, and triple amino acid substitutions within this region abolish both transactivation and AP-1 interference independently of their effect on T3 binding.","method":"c-ErbA/v-ErbA chimeras; site-directed mutagenesis; transient transfection reporter assays; erythroid differentiation assays","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — systematic mutagenesis with three independent functional readouts in one rigorous study (PMID:8098843)","pmids":["8098843"],"is_preprint":false},{"year":1991,"finding":"c-ErbA alpha (TRα1) represses AP-1-mediated transcriptional activation of the collagenase gene promoter by decreasing AP-1 activity in a ligand-activated manner; v-ErbA fails to repress AP-1 and acts as a dominant negative by overcoming c-ErbA alpha-mediated AP-1 repression, thereby abrogating growth-inhibitory responses to retinoic acid.","method":"Co-transfection of AP-1 reporter constructs with c-ErbA alpha or v-ErbA expression vectors; AP-1 activity assays; growth assays in chicken embryo fibroblasts with retinoic acid","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reporter assays plus growth phenotype, single lab with two orthogonal methods (PMID:1682056)","pmids":["1682056"],"is_preprint":false},{"year":1993,"finding":"Unliganded TRα (c-ErbA alpha), but not v-ErbA, suppresses RAR-dependent transactivation by competing for the shared dimerization partner RXR; TRα/RXR competition dissociates preformed RAR/RXR–RARE ternary complexes in vitro; a single Pro349→Ser mutation in v-ErbA's dimerization interface abolishes this trans-dominant phenotype when introduced into TRα.","method":"Gel-shift (EMSA) showing dissociation of RAR/RXR–RARE complex; co-transfection with RXR to alleviate suppression; site-directed mutagenesis of dimerization interface","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro EMSA reconstitution plus mutagenesis plus co-transfection rescue, multiple orthogonal methods in one study (PMID:8096810)","pmids":["8096810"],"is_preprint":false},{"year":1993,"finding":"v-ErbA requires heterodimerization with RXR-alpha for sufficient DNA binding to natural thyroid hormone response elements; only v-ErbA–RXR-alpha heterodimers bind TREs with the affinity required for potent transcriptional repression; C-terminal mutations that abolish v-ErbA–RXR-alpha heterodimerization also abolish repressor activity.","method":"EMSA heterodimerization assays; co-transfection with dominant-negative RXR; C-terminal mutagenesis of v-ErbA","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 1 / Moderate — EMSA reconstitution plus mutagenesis plus reporter assays, multiple methods in one study (PMID:8093812)","pmids":["8093812"],"is_preprint":false},{"year":1993,"finding":"c-ErbA alpha (TRα1) activates transcription through an RSV-LTR T3 response element (RSV-T3RE) in the absence of ligand via a unique N-terminal activation domain; T3 reverses this ligand-independent activation; c-ErbA alpha/RXR heterodimers or c-ErbA alpha homodimers recognize this element; c-ErbA alpha adopts a different conformation on RSV-T3RE versus classical T3RE, enabling selective deployment of N-terminal vs. C-terminal activation domains.","method":"Transient transfection of RSV-T3RE reporter with c-ErbA alpha domain mutants; EMSA; N-terminal deletion analysis","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — reporter assays with domain mutants plus EMSA, two orthogonal methods in one study (PMID:7903219)","pmids":["7903219"],"is_preprint":false},{"year":1993,"finding":"A 'hinge-region' Pro→Arg mutation in v-ErbA (equivalent to TRα hinge) selectively abolishes transcriptional repression (trans-repression) without affecting DNA binding or hormone binding of TRα, suggesting that trans-repression—not dominant-negative blockade of receptor activation—is the primary oncogenic function of v-erbA.","method":"Site-directed mutagenesis of hinge Pro→Arg in v-ErbA and TRα; co-transfection reporter assays; T3 and retinoic acid response assays","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Moderate — mutagenesis plus multiple reporter assays with selective functional dissection in one study (PMID:7902566)","pmids":["7902566"],"is_preprint":false},{"year":1989,"finding":"A DNA-binding mutation (Gly73→Ser) in the zinc-finger domain of v-ErbA is in part responsible for its inability to activate transcription; chimeric ER/TRα constructs with the v-erbA DNA-binding domain fail to activate reporters, whereas those with the c-erbA DNA-binding domain activate transcription.","method":"Chimeric estrogen/thyroid hormone receptor constructs; transient co-transfection reporter assays","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — chimeric receptor reporter assays, single lab, single method (PMID:1975094)","pmids":["1975094"],"is_preprint":false},{"year":1991,"finding":"v-ErbA and c-ErbA both bind directly to sequences within the CAII (carbonic anhydrase II) promoter; this erbA-binding site confers T3 responsiveness to a heterologous promoter; v-ErbA requires overexpression to overcome c-ErbA/T3-mediated activation at equimolar ratios in stably transformed erythroblasts.","method":"DNA-protein binding assays (EMSA/footprinting); stable retroviral co-expression of v-erbA and c-erbA; T3-responsive reporter and endogenous gene expression assays","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct DNA binding plus stable gene expression analysis plus reporter assays, multiple orthogonal methods (PMID:1682217)","pmids":["1682217"],"is_preprint":false},{"year":1988,"finding":"c-erbA/TRα1 protein and in vitro-translated c-erbA products are localized predominantly to the nucleus; multiple c-erbA-encoded proteins of 27–46 kDa arise from internal initiations within the c-erbA mRNA, generating a nested set of proteins; all are nuclear.","method":"Anti-erbA antibodies; immunoprecipitation; subcellular fractionation; in vitro translation; partial proteolytic mapping","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — fractionation, in vitro translation, and immunoprecipitation in a single study with multiple methods (PMID:3054510)","pmids":["3054510"],"is_preprint":false},{"year":1988,"finding":"c-erbA alpha and c-erbA beta proteins mediate thyroid hormone-dependent regulation of the rat growth hormone and prolactin gene regulatory sequences, functioning as T3 receptors; in receptor-deficient cells both act as hormone-dependent modulators, confirming their identity as functional T3 receptors.","method":"Transient expression of c-erbA alpha and c-erbA beta with chimeric GH/PRL reporter constructs in receptor-deficient (235-1) and receptor-containing (GH4C1, GH1) cell lines","journal":"Molecular endocrinology (Baltimore, Md.)","confidence":"High","confidence_rationale":"Tier 2 / Moderate — cell-line complementation with receptor-deficient cells plus multiple receptor subtypes and promoters, single lab but rigorous design (PMID:2903439)","pmids":["2903439"],"is_preprint":false},{"year":1990,"finding":"The chicken c-erbA alpha protein restores T3 responsiveness (malic enzyme, PEPCK, Na+/K+-ATPase gene induction and direct activation of MLV promoter) in FAO receptor-deficient hepatoma cells in a ligand-dependent manner, proving it is a functional T3 receptor.","method":"Retroviral expression of cTR-alpha in FAO cells; Northern blot analysis of T3-responsive endogenous genes; T3 dose-response experiments","journal":"Molecular endocrinology (Baltimore, Md.)","confidence":"High","confidence_rationale":"Tier 2 / Moderate — cell complementation with multiple endogenous gene readouts, single lab (PMID:2158623)","pmids":["2158623"],"is_preprint":false},{"year":1990,"finding":"Overexpressed TRα (c-erbA/T3 receptor) modulates erythroid differentiation and erythrocyte-specific gene expression in a T3-dependent fashion in erythroid cells; v-erbA has lost the T3-dependent regulatory activity but constitutively displays a repressor function; the region responsible for loss of hormone-dependent activity in v-erbA maps to the extreme C-terminus of c-erbA, including a cluster of conserved residues forming a predicted amphipathic alpha-helix.","method":"Retroviral expression of chimeric v-/c-erbA proteins in erythroid cells; erythroid differentiation assays; erythrocyte gene expression analysis","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — chimeric protein mapping in cells with differentiation and gene expression readouts, replicated concept across labs (PMID:1972036, PMID:8098843)","pmids":["1972036"],"is_preprint":false},{"year":1996,"finding":"Rev-ErbA alpha (encoded on the opposite strand of the THRA locus) physically interacts with the corepressor N-CoR/RIP13 through a domain composed of two receptor interaction domains (ID-I and ID-II); this interaction requires an intact E (ligand-binding) region of Rev-ErbA alpha; overexpression of N-CoR interaction domains relieves Rev-ErbA alpha-mediated repression.","method":"Mammalian two-hybrid system; co-transfection repression assays with dominant-negative N-CoR fragments; deletion mutagenesis of Rev-ErbA alpha E region","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — two-hybrid and co-transfection assays, single lab, two orthogonal methods (PMID:8948627)","pmids":["8948627"],"is_preprint":false},{"year":2000,"finding":"v-ErbA recruits both N-CoR and HDAC3 to chromatin for transcriptional repression, but—unlike TRα—requires mature chromatin (not partial chromatinization) for this repression; v-ErbA is less competent than TRα for binding TFIIB in vitro and in vivo, explaining its impaired silencing on partly chromatinized templates.","method":"Xenopus oocyte chromatin assembly assays; histone deacetylase inhibitor (TSA) treatment; co-immunoprecipitation of N-CoR and HDAC3; in vitro TFIIB binding assays","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — Xenopus oocyte reconstitution plus Co-IP plus in vitro binding, multiple orthogonal methods in one study (PMID:10921888)","pmids":["10921888"],"is_preprint":false},{"year":1991,"finding":"The antisense RNA Rev-ErbA alpha (transcribed from the opposite strand of the THRA locus) inhibits splicing of c-erbA alpha 2 pre-mRNA in vitro; both an antisense RNA spanning the 3′ splice site and a shorter exon-complementary RNA block splicing, suggesting that base-pairing with Rev-ErbA alpha shifts the alpha1/alpha2 ratio by inhibiting alpha2 mRNA splicing.","method":"In vitro splicing assay with c-erbA alpha 2 pre-mRNA; addition of antisense Rev-ErbA alpha RNA fragments; competition with non-complementary RNAs as control","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution of splicing inhibition with strand-specific controls, single lab (PMID:1657988)","pmids":["1657988"],"is_preprint":false},{"year":1992,"finding":"The unique C-terminus of TRα1 is required for heterodimerization with nuclear proteins on T3-response elements; the unique C-terminus of c-erbA alpha 2 acts as an inhibitory domain reducing DNA binding; chimera experiments show the last 100–150 aa of TRα1 are sufficient to confer heterodimerization competence on alpha 2.","method":"In vitro synthesis in E. coli and reticulocyte lysates; EMSA with TR alpha 1, alpha 2, and C-terminal deletion/chimeric mutants; heterodimerization assays on TREs","journal":"Molecular endocrinology (Baltimore, Md.)","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with systematic chimeric and deletion mutants, EMSA, single lab (PMID:1318505)","pmids":["1318505"],"is_preprint":false},{"year":1993,"finding":"Unliganded TRα1 (c-erbA alpha) expressed in PC12 neuronal progenitor cells inhibits NGF-induced neuronal differentiation and represses neuron-specific gene expression; T3 binding relieves this inhibition, allowing normal differentiation; TRα1 also constitutively blocks dexamethasone-induced chromaffin differentiation, establishing TRα1 as a ligand-controlled switch for neuronal vs. chromaffin progenitor commitment.","method":"Retroviral expression of c-erbA/TR alpha-1 or v-erbA in PC12 cells; NGF and dexamethasone differentiation assays; neuronal gene expression analysis","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean gain-of-function in a defined cell line with multiple differentiation readouts and hormone dose-response, single lab (PMID:8385673)","pmids":["8385673"],"is_preprint":false},{"year":1994,"finding":"Unliganded TRα1 induces trkB mRNA expression (with concomitant loss of trkA and trkC) in N2a neuroblastoma cells in a ligand-independent manner; both TRα1 and TRβ1 produce this effect upon transient expression.","method":"Stable and transient expression of c-erbA/TR alpha 1 in N2a cells; Northern blot analysis of trk mRNAs; T3 treatment (no effect); tyrosine phosphorylation assay of induced gp145trkB","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — gene expression assay with functional protein validation, single lab, single main method (PMID:8134111)","pmids":["8134111"],"is_preprint":false},{"year":1997,"finding":"Two novel N-terminally truncated isoforms of TRα (TRΔα1 and TRΔα2) are transcribed from an internal promoter within intron 7 of the c-erbA alpha gene; TRΔα1 antagonizes T3-dependent and retinoic-acid-dependent transcriptional activation by TRα1 and 9-cis-RAR alpha but does not affect RAR alpha-dependent activation.","method":"Identification of internal promoter by 5′ RACE; expression vector transfection; T3- and RA-responsive reporter assays with TRΔα1 co-expression","journal":"Molecular endocrinology (Baltimore, Md.)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — promoter identification plus reporter co-transfection with selective inhibition profile, single lab (PMID:9259319)","pmids":["9259319"],"is_preprint":false},{"year":2001,"finding":"A targeted mutation in Thra (Thra(tm2)) that deletes TRα2 and causes overexpression of TRα1 suppresses the deafness and thyroid hyperactivity phenotypes of Thrb-null mice, indicating that increased TRα1 expression can substitute for loss of TRβ and that TRα2 is dispensable for hearing.","method":"Genetic epistasis: Thra(tm2) allele introduced into Thrb(tm1/tm1) null background; auditory brainstem response thresholds; thyroid hormone measurements","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean genetic epistasis in mice with two independent phenotypic readouts (hearing, thyroid), single lab (PMID:11726557)","pmids":["11726557"],"is_preprint":false},{"year":2015,"finding":"Truncating and missense mutations in THRA cause a distinct resistance-to-thyroid-hormone syndrome (RTHα) with low fT4/fT3 ratio, macrocephaly, and skeletal dysplasia; missense mutations show milder phenotypes than truncating mutations (genotype-phenotype correlation), establishing THRA as the causal gene.","method":"Whole exome sequencing followed by Sanger sequencing; longitudinal clinical assessment; biochemical thyroid function tests in six patients from five families","journal":"Journal of medical genetics","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — human genetic causation established by sequencing in multiple independent families with consistent phenotype, but no in vitro functional assay in this paper (PMID:25670821)","pmids":["25670821"],"is_preprint":false},{"year":2015,"finding":"A de novo missense mutation in THRA (N359Y) affecting TRα1 causes decreased T3 binding affinity and a dominant-negative effect on wild-type TRα1-mediated transcription; the mutation also affects the non-receptor isoform TRα2.","method":"Whole exome sequencing; in vitro transcriptional activity assays of mutant vs. wild-type TRα1; T3 binding assays; dominant-negative co-transfection assays","journal":"The Journal of clinical endocrinology and metabolism","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — functional assays (T3 binding, reporter, dominant-negative) on a single patient mutation, single lab (PMID:26037512)","pmids":["26037512"],"is_preprint":false},{"year":1988,"finding":"v-ErbA protein exists in both nuclear and cytoplasmic forms; both forms can bind DNA; a mutation that inhibits DNA binding also inhibits nuclear localization and abolishes the ability to potentiate erythroid transformation, linking DNA binding to nuclear localization and oncogenic function.","method":"Site-specific antisera; subcellular fractionation; DNA binding assays; biological transformation assays","journal":"Journal of virology","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — fractionation, DNA binding, and transformation assays with DNA-binding mutant, single lab (PMID:2826814)","pmids":["2826814"],"is_preprint":false},{"year":1990,"finding":"A subpopulation of the v-erbA protein (a TRα-derived nuclear receptor) is glycosylated, identifying TRα-related proteins as members of the glycoprotein class of nuclear transcription factors.","method":"Metabolic labeling with [3H]-glucosamine; glycosidase treatment; immunoprecipitation","journal":"Journal of virology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single biochemical observation in v-erbA (surrogate for TRα), single method, single lab (PMID:1967151)","pmids":["1967151"],"is_preprint":false},{"year":1993,"finding":"ErbA oncogene protein (v-ErbA) interferes with TRα and trans-retinoic acid receptors by competing for binding to their respective DNA response elements; v-ErbA does not heterodimerize with RAR or TR in a functionally significant manner for repression of these receptors, but efficiently heterodimerizes with RXR, which dramatically impairs RXR-mediated gene activation.","method":"EMSA competition assays; co-transfection reporter assays; heterodimerization assays","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — EMSA plus reporter assays, single lab with two methods (PMID:8105369)","pmids":["8105369"],"is_preprint":false}],"current_model":"THRA encodes thyroid hormone receptor alpha (TRα1), a ligand-dependent nuclear transcription factor that, upon T3 binding, activates T3-responsive genes via thyroid hormone response elements (TREs); in the absence of T3, unliganded TRα1 represses target genes by recruiting corepressors (N-CoR/HDAC3); an alternatively spliced isoform TRα2 lacks T3 binding and acts as a dominant-negative inhibitor of TRα1 by competing for TREs while being unable to heterodimerize; additional N-terminally truncated isoforms (TRΔα1/2) from an internal promoter further attenuate receptor activity; TRα1 is phosphorylated at Ser12 by casein kinase II and at Ser28/29 by PKA/PKC, modulating its transcriptional function; the extreme C-terminal helix AF-2 is essential for T3-dependent transactivation, AP-1 interference, and erythroid differentiation; germline THRA loss-of-function or dominant-negative mutations cause resistance to thyroid hormone alpha (RTHα) with growth retardation, skeletal dysplasia, and low fT4/fT3 ratio, while overexpression of TRα1 can compensate for loss of TRβ in auditory and thyroid function."},"narrative":{"mechanistic_narrative":"THRA encodes thyroid hormone receptor alpha (TRα1, c-erbA alpha 1), a nuclear, ligand-dependent transcription factor that controls T3-responsive gene programs governing growth, differentiation, and metabolism [PMID:2537467, PMID:2903438, PMID:2554288, PMID:3054510, PMID:2903439]. Its hormone-binding domain occupies the carboxy-terminal half of the protein, positionally analogous to that of steroid receptors [PMID:3359993, PMID:2464752], and TRα1 functions as a bona fide T3 receptor that restores hormone-responsive induction of endogenous genes (growth hormone, prolactin, malic enzyme, PEPCK, Na+/K+-ATPase) in receptor-deficient cells [PMID:2903439, PMID:2158623]. A conserved 9-residue amphipathic helix at the extreme C-terminus (AF-2) is essential for T3-dependent transactivation, AP-1 interference, and erythroid differentiation, independently of T3 binding itself [PMID:8098843, PMID:1972036]. TRα1 efficiently activates transcription only as part of an RXR heterodimer, with the unique C-terminus conferring heterodimerization competence on TREs [PMID:1318505], and unliganded receptor can repress competing pathways by sequestering RXR and dissociating RAR/RXR complexes [PMID:8096810]; repression operates through corepressor and HDAC3 recruitment to chromatin [PMID:10921888]. TRα1 acts as a ligand-controlled developmental switch: in the unliganded state it blocks NGF-induced neuronal differentiation, with T3 relieving the block [PMID:8385673]. Receptor output is tuned at multiple layers from the same locus: alternative splicing produces TRα2, which cannot bind T3 and antagonizes TRα1/TRβ in dominant-negative fashion [PMID:2537467, PMID:2903438, PMID:2554288]; an internal intron-7 promoter yields N-terminally truncated TRΔα isoforms that further attenuate TRα1 activity [PMID:9259319]; the antisense Rev-ErbA alpha RNA shifts the α1/α2 ratio by inhibiting α2 splicing [PMID:1657988]; and TRα1 is phosphorylated at N-terminal Ser12 by casein kinase II and at Ser28/29 by PKA/PKC [PMID:2903825, PMID:2552374]. Germline truncating and missense THRA mutations cause resistance to thyroid hormone alpha (RTHα), a syndrome of low fT4/fT3 ratio, macrocephaly, and skeletal dysplasia, acting through reduced T3 binding and dominant-negative interference [PMID:25670821, PMID:26037512]. Much of the early mechanistic dissection was performed through the constitutively repressive viral homolog v-ErbA, which lacks the AF-2 helix and functions as a dominant-negative oncogene antagonizing cellular TRα [PMID:2733791, PMID:1972036, PMID:1682217].","teleology":[{"year":1988,"claim":"Before its function was defined, it was unknown whether the c-erbA alpha protein was itself a hormone receptor; locating the hormone-binding domain to the C-terminal half established it as a steroid/nuclear receptor-class molecule and pinpointed where ligand control resides.","evidence":"Chimeric v-erbA/c-erbA proteins and ligand-binding assays of in vitro translated deletion mutants","pmids":["3359993","2464752"],"confidence":"High","gaps":["Structural basis of T3 binding not resolved","Did not address DNA target sequences or cofactor requirements"]},{"year":1988,"claim":"It was unclear whether c-erbA proteins were functional T3 receptors in cells; complementation in receptor-deficient lines showed they confer hormone-dependent regulation of growth hormone/prolactin and other endogenous genes, confirming receptor identity and predominantly nuclear localization.","evidence":"Transient expression with chimeric GH/PRL reporters in receptor-deficient versus receptor-containing cell lines; antibody fractionation and in vitro translation","pmids":["2903439","3054510"],"confidence":"High","gaps":["Target gene repertoire incompletely mapped","Internal-initiation isoform functions not yet defined"]},{"year":1989,"claim":"The question of how a single locus produces opposing activities was answered by showing alternative splicing yields TRα1 (T3-activating) and TRα2 (non-T3-binding, dominant-negative), establishing intragenic antagonism as a regulatory principle.","evidence":"Transient transfection of T3-responsive reporters with in vitro translation and ligand-binding assays across multiple labs","pmids":["2537467","2903438","2554288"],"confidence":"High","gaps":["Mechanism of TRα2 dominant-negativity not yet localized to a domain","Splicing control of the α1/α2 ratio unknown"]},{"year":1989,"claim":"To understand how the cellular receptor is post-translationally regulated, N-terminal phosphorylation sites were defined: PKA/PKC-enhanced Ser28/29 and casein kinase II-targeted Ser12, identifying kinase inputs onto receptor function.","evidence":"In vivo metabolic labeling, tryptic phosphopeptide mapping, in vitro kinase assays with purified PKA and CK2, and Ser12→Ala mutagenesis","pmids":["2903825","2552374"],"confidence":"High","gaps":["Functional consequence of each phosphosite on transactivation not fully quantified","Upstream signals driving these modifications in vivo unknown"]},{"year":1989,"claim":"The transforming v-ErbA homolog was shown to be a constitutive repressor that dominantly blocks T3-dependent activation, providing the key tool to dissect activating versus repressive receptor functions; a zinc-finger DNA-binding mutation (Gly73→Ser) was linked to its loss of activation.","evidence":"Co-transfection of v-erbA/c-erbA with T3 reporters and chimeric ER/TRα DNA-binding-domain constructs","pmids":["2733791","1972036","1682217","1975094"],"confidence":"High","gaps":["Repression mechanism (cofactors) not yet identified","Relative contributions of DNA-binding versus ligand-binding lesions unresolved"]},{"year":1990,"claim":"Mapping the difference between activating cellular receptor and repressive virus showed a conserved C-terminal 9-residue amphipathic helix (AF-2) is essential for T3-dependent transactivation, AP-1 interference, and erythroid differentiation, independent of T3 binding.","evidence":"c-ErbA/v-ErbA chimeras, single/double/triple substitution mutagenesis, reporter and erythroid differentiation assays","pmids":["8098843","1972036"],"confidence":"High","gaps":["Identity of coactivators engaging AF-2 not defined","Structural mechanism of the helix not resolved"]},{"year":1991,"claim":"How TRα cross-talks with other signaling outputs was clarified by demonstrating ligand-activated TRα1 represses AP-1-driven collagenase transcription while v-ErbA fails to do so, linking receptor activity to control of cell growth.","evidence":"Co-transfection AP-1 reporter assays and retinoic-acid growth assays in chicken embryo fibroblasts","pmids":["1682056"],"confidence":"High","gaps":["Molecular contact mediating AP-1 interference not mapped","Physiological relevance in mammals not tested here"]},{"year":1992,"claim":"The basis of differential isoform DNA binding was localized: the unique TRα1 C-terminus enables heterodimerization on TREs, whereas the unique TRα2 C-terminus is an inhibitory domain that reduces DNA binding.","evidence":"In vitro synthesis with EMSA and heterodimerization assays of TRα1, TRα2, deletion and chimeric mutants","pmids":["1318505"],"confidence":"High","gaps":["Heterodimer partner identity not fully specified here","In vivo relevance of isoform DNA-binding differences untested"]},{"year":1993,"claim":"Mechanisms of trans-dominant antagonism were resolved: unliganded TRα suppresses RAR signaling by competing for shared RXR partner and dissociating RAR/RXR–RARE complexes, while v-ErbA functions chiefly through RXR heterodimerization and hinge-region-dependent trans-repression.","evidence":"EMSA dissociation and competition assays, RXR co-transfection rescue, and dimerization-interface/hinge mutagenesis (Pro349→Ser; Pro→Arg)","pmids":["8096810","8093812","7902566","8105369"],"confidence":"High","gaps":["Quantitative contribution of competition versus active repression in vivo unclear","Endogenous gene targets of RXR sequestration not enumerated"]},{"year":1993,"claim":"TRα1 was established as a ligand-controlled developmental switch: unliganded receptor blocks NGF-induced neuronal differentiation and chromaffin commitment, with T3 relieving the neuronal block.","evidence":"Retroviral expression of TRα1/v-erbA in PC12 cells with NGF and dexamethasone differentiation and neuronal gene-expression assays; trk mRNA analysis in N2a cells","pmids":["8385673","8134111"],"confidence":"High","gaps":["Direct target genes mediating the differentiation switch not all defined","In vivo developmental requirement not addressed in these systems"]},{"year":1996,"claim":"The corepressor logic underlying receptor-mediated silencing was advanced by showing the antisense locus product Rev-ErbA alpha binds N-CoR via two interaction domains, foreshadowing the corepressor machinery that TRα-class receptors deploy.","evidence":"Mammalian two-hybrid and co-transfection repression assays with dominant-negative N-CoR fragments","pmids":["8948627"],"confidence":"Medium","gaps":["Direct demonstration on TRα1 itself not provided in this finding","Single-lab two-hybrid without structural validation"]},{"year":2000,"claim":"The chromatin-level repression mechanism was defined: v-ErbA recruits N-CoR and HDAC3 to repress, but unlike TRα requires mature chromatin and binds TFIIB poorly, dissecting why the viral protein silences less efficiently on partly assembled templates.","evidence":"Xenopus oocyte chromatin assembly assays, TSA treatment, Co-IP of N-CoR/HDAC3, and in vitro TFIIB binding","pmids":["10921888"],"confidence":"High","gaps":["Equivalent stepwise mechanism for endogenous mammalian TRα not directly shown","Other corepressors/coactivators not surveyed"]},{"year":1997,"claim":"Additional layers of locus-encoded receptor tuning were identified: an internal intron-7 promoter generates N-terminally truncated TRΔα isoforms that selectively antagonize TRα1, and antisense Rev-ErbA alpha RNA inhibits TRα2 splicing to shift the α1/α2 ratio.","evidence":"5′ RACE promoter identification with reporter co-transfection (TRΔα1) and in vitro splicing assays with strand-specific antisense RNA","pmids":["9259319","1657988"],"confidence":"Medium","gaps":["Physiological abundance and tissue distribution of TRΔα isoforms not quantified","In vivo significance of antisense splicing regulation not established"]},{"year":2001,"claim":"Genetic epistasis in mice answered whether TRα1 and TRβ functions overlap, showing that increased TRα1 expression substitutes for loss of TRβ in deafness and thyroid hyperactivity, and that TRα2 is dispensable for hearing.","evidence":"Thra(tm2) allele in Thrb-null background with auditory brainstem response and thyroid hormone measurements","pmids":["11726557"],"confidence":"High","gaps":["Tissues where TRα1 cannot substitute for TRβ not delineated here","Molecular basis of functional redundancy not addressed"]},{"year":2015,"claim":"The human disease relevance was established: germline THRA truncating and missense mutations cause resistance to thyroid hormone alpha (RTHα) through reduced T3 binding and dominant-negative interference, with genotype-phenotype correlation.","evidence":"Whole exome and Sanger sequencing in multiple families with longitudinal clinical/biochemical assessment, plus in vitro T3-binding, reporter, and dominant-negative assays of the N359Y mutant","pmids":["25670821","26037512"],"confidence":"Medium","gaps":["Tissue-specific mechanisms of skeletal and growth phenotypes not fully resolved","Functional assays performed on limited mutation set"]},{"year":null,"claim":"How the multiple regulatory layers (splicing, antisense RNA, internal promoter, phosphorylation, cofactor recruitment) are integrated to set tissue-specific TRα1 output in human physiology and RTHα remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No integrated in vivo model linking phosphorylation, isoform ratios, and cofactor recruitment","Tissue-resolved target gene programs of TRα1 not comprehensively mapped"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[0,10,15,16,22]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[13,21,28]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[2]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[14,28]}],"pathway":[{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[0,15,16]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[22]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[17,22]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[26,27]}],"complexes":[],"partners":["RXRA","NCOR1","HDAC3","TFIIB"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P10827","full_name":"Thyroid hormone receptor alpha","aliases":["Nuclear receptor subfamily 1 group A member 1","V-erbA-related protein 7","EAR-7","c-erbA-1","c-erbA-alpha"],"length_aa":490,"mass_kda":54.8,"function":"Nuclear hormone receptor that can act as a repressor or activator of transcription. High affinity receptor for thyroid hormones, including triiodothyronine and thyroxine Does not bind thyroid hormone and functions as a weak dominant negative inhibitor of thyroid hormone action","subcellular_location":"Cytoplasm; Nucleus","url":"https://www.uniprot.org/uniprotkb/P10827/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/THRA","classification":"Not Classified","n_dependent_lines":22,"n_total_lines":1208,"dependency_fraction":0.018211920529801324},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/THRA","total_profiled":1310},"omim":[{"mim_id":"616223","title":"ANGIOPOIETIN-LIKE 8; ANGPTL8","url":"https://www.omim.org/entry/616223"},{"mim_id":"615354","title":"LIGAND-DEPENDENT NUCLEAR RECEPTOR-INTERACTING FACTOR 1; LRIF1","url":"https://www.omim.org/entry/615354"},{"mim_id":"614450","title":"HYPOTHYROIDISM, CONGENITAL, NONGOITROUS, 6; CHNG6","url":"https://www.omim.org/entry/614450"},{"mim_id":"612054","title":"CCR4-NOT TRANSCRIPTION COMPLEX, SUBUNIT 9; CNOT9","url":"https://www.omim.org/entry/612054"},{"mim_id":"611583","title":"AT-RICH INTERACTION DOMAIN-CONTAINING PROTEIN 5A; ARID5A","url":"https://www.omim.org/entry/611583"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Uncertain","locations":[{"location":"Cytosol","reliability":"Uncertain"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"brain","ntpm":400.8}],"url":"https://www.proteinatlas.org/search/THRA"},"hgnc":{"alias_symbol":["EAR-7.1/EAR-7.2","THRA3","AR7","ERBA","NR1A1","TRalpha","TRalpha1","TRalpha2","c-ERBA-1","c-erbA","THRalpha","THRalpha1","THRalpha2"],"prev_symbol":["THRA1","THRA2","ERBA1"]},"alphafold":{"accession":"P10827","domains":[{"cath_id":"3.30.50.10","chopping":"42-127","consensus_level":"medium","plddt":94.6478,"start":42,"end":127},{"cath_id":"1.10.565.10","chopping":"161-385_398-406","consensus_level":"high","plddt":84.8458,"start":161,"end":406}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P10827","model_url":"https://alphafold.ebi.ac.uk/files/AF-P10827-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P10827-F1-predicted_aligned_error_v6.png","plddt_mean":73.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=THRA","jax_strain_url":"https://www.jax.org/strain/search?query=THRA"},"sequence":{"accession":"P10827","fasta_url":"https://rest.uniprot.org/uniprotkb/P10827.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P10827/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P10827"}},"corpus_meta":[{"pmid":"3755102","id":"PMC_3755102","title":"The chicken oestrogen receptor sequence: homology with v-erbA and the human oestrogen and glucocorticoid receptors.","date":"1986","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/3755102","citation_count":645,"is_preprint":false},{"pmid":"2733791","id":"PMC_2733791","title":"Protein encoded by v-erbA functions as a thyroid-hormone receptor antagonist.","date":"1989","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/2733791","citation_count":616,"is_preprint":false},{"pmid":"2537467","id":"PMC_2537467","title":"Inhibition of thyroid hormone action by a non-hormone binding c-erbA protein generated by alternative mRNA splicing.","date":"1989","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/2537467","citation_count":433,"is_preprint":false},{"pmid":"3299059","id":"PMC_3299059","title":"Amplification of the neu (c-erbB-2) oncogene in human mammmary tumors is relatively frequent and is often accompanied by amplification of the linked c-erbA oncogene.","date":"1987","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/3299059","citation_count":369,"is_preprint":false},{"pmid":"2901090","id":"PMC_2901090","title":"Alternative splicing generates messages encoding rat c-erbA proteins that do not bind thyroid hormone.","date":"1988","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/2901090","citation_count":312,"is_preprint":false},{"pmid":"2542765","id":"PMC_2542765","title":"A novel member of the thyroid/steroid hormone receptor family is encoded by the opposite strand of the rat c-erbA alpha transcriptional unit.","date":"1989","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/2542765","citation_count":309,"is_preprint":false},{"pmid":"6297784","id":"PMC_6297784","title":"Transforming capacities of avian erythroblastosis virus mutants deleted in the erbA or erbB oncogenes.","date":"1983","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/6297784","citation_count":301,"is_preprint":false},{"pmid":"3281095","id":"PMC_3281095","title":"Genetic alterations of the c-erbB-2 oncogene occur frequently in tubular adenocarcinoma of the stomach and are often accompanied by amplification of the v-erbA homologue.","date":"1988","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/3281095","citation_count":284,"is_preprint":false},{"pmid":"2162351","id":"PMC_2162351","title":"Relationship of c-erbA mRNA content to tissue triiodothyronine nuclear binding capacity and function in developing and adult rats.","date":"1990","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/2162351","citation_count":283,"is_preprint":false},{"pmid":"2903438","id":"PMC_2903438","title":"Identification of a rat c-erbA alpha-related protein which binds deoxyribonucleic acid but does not bind thyroid hormone.","date":"1988","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/2903438","citation_count":275,"is_preprint":false},{"pmid":"2153150","id":"PMC_2153150","title":"Differential and tissue-specific regulation of the multiple rat c-erbA messenger RNA species by thyroid hormone.","date":"1990","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/2153150","citation_count":250,"is_preprint":false},{"pmid":"2539258","id":"PMC_2539258","title":"Two erbA homologs encoding proteins with different T3 binding capacities are transcribed from opposite DNA strands of the same genetic locus.","date":"1989","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/2539258","citation_count":244,"is_preprint":false},{"pmid":"1972036","id":"PMC_1972036","title":"v-erbA oncogene activation entails the loss of hormone-dependent regulator activity of c-erbA.","date":"1990","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/1972036","citation_count":240,"is_preprint":false},{"pmid":"8474464","id":"PMC_8474464","title":"The orphan receptor Rev-ErbA alpha activates transcription via a novel response element.","date":"1993","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/8474464","citation_count":208,"is_preprint":false},{"pmid":"6323162","id":"PMC_6323162","title":"Chromosomal localisation of the human homologues to the oncogenes erbA and B.","date":"1984","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/6323162","citation_count":199,"is_preprint":false},{"pmid":"1663215","id":"PMC_1663215","title":"Independent expression of the alpha and beta c-erbA genes in developing rat brain.","date":"1991","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/1663215","citation_count":194,"is_preprint":false},{"pmid":"2153155","id":"PMC_2153155","title":"A base mutation of the C-erbA beta thyroid hormone receptor in a kindred with generalized thyroid hormone resistance. Molecular heterogeneity in two other kindreds.","date":"1990","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/2153155","citation_count":178,"is_preprint":false},{"pmid":"8344913","id":"PMC_8344913","title":"Induction of Rev-ErbA alpha, an orphan receptor encoded on the opposite strand of the alpha-thyroid hormone receptor gene, during adipocyte differentiation.","date":"1993","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/8344913","citation_count":172,"is_preprint":false},{"pmid":"2905763","id":"PMC_2905763","title":"Tight linkage between the syndrome of generalized thyroid hormone resistance and the human c-erbA beta gene.","date":"1988","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/2905763","citation_count":161,"is_preprint":false},{"pmid":"1682056","id":"PMC_1682056","title":"A novel mechanism of action for v-ErbA: abrogation of the inactivation of transcription factor AP-1 by retinoic acid and thyroid hormone receptors.","date":"1991","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/1682056","citation_count":159,"is_preprint":false},{"pmid":"3009024","id":"PMC_3009024","title":"v-erbA cooperates with sarcoma oncogenes in leukemic cell transformation.","date":"1986","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/3009024","citation_count":159,"is_preprint":false},{"pmid":"2830979","id":"PMC_2830979","title":"v-erbA specifically suppresses transcription of the avian erythrocyte anion transporter (band 3) gene.","date":"1988","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/2830979","citation_count":157,"is_preprint":false},{"pmid":"2903825","id":"PMC_2903825","title":"Activation of protein kinase C or cAMP-dependent protein kinase increases phosphorylation of the c-erbA-encoded thyroid hormone receptor and of the v-erbA-encoded protein.","date":"1988","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/2903825","citation_count":155,"is_preprint":false},{"pmid":"1657988","id":"PMC_1657988","title":"Inhibition of c-erbA mRNA splicing by a naturally occurring antisense RNA.","date":"1991","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/1657988","citation_count":149,"is_preprint":false},{"pmid":"2903439","id":"PMC_2903439","title":"c-erbA protooncogenes mediate thyroid hormone-dependent and independent regulation of the rat growth hormone and prolactin genes.","date":"1988","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/2903439","citation_count":147,"is_preprint":false},{"pmid":"6589608","id":"PMC_6589608","title":"A human c-erbA oncogene homologue is closely proximal to the chromosome 17 breakpoint in acute promyelocytic leukemia.","date":"1984","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/6589608","citation_count":141,"is_preprint":false},{"pmid":"2554288","id":"PMC_2554288","title":"Human carboxyl-terminal variant of alpha-type c-erbA inhibits trans-activation by thyroid hormone receptors without binding thyroid hormone.","date":"1989","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/2554288","citation_count":134,"is_preprint":false},{"pmid":"9259319","id":"PMC_9259319","title":"Identification of transcripts initiated from an internal promoter in the c-erbA alpha locus that encode inhibitors of retinoic acid receptor-alpha and triiodothyronine receptor activities.","date":"1997","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/9259319","citation_count":132,"is_preprint":false},{"pmid":"3359993","id":"PMC_3359993","title":"Characterization of the hormone-binding domain of the chicken c-erbA/thyroid hormone receptor protein.","date":"1988","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/3359993","citation_count":127,"is_preprint":false},{"pmid":"2573734","id":"PMC_2573734","title":"Presence of two members of c-erbA receptor gene family (c-erbA beta and c-erbA2) in smallest region of somatic homozygosity on chromosome 3p21-p25 in human breast carcinoma.","date":"1989","source":"Journal of the National Cancer Institute","url":"https://pubmed.ncbi.nlm.nih.gov/2573734","citation_count":126,"is_preprint":false},{"pmid":"1653889","id":"PMC_1653889","title":"A homozygous deletion in the c-erbA beta thyroid hormone receptor gene in a patient with generalized thyroid hormone resistance: isolation and characterization of the mutant receptor.","date":"1991","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/1653889","citation_count":121,"is_preprint":false},{"pmid":"7903219","id":"PMC_7903219","title":"A novel cis element mediating ligand-independent activation by c-ErbA: implications for hormonal regulation.","date":"1993","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/7903219","citation_count":120,"is_preprint":false},{"pmid":"2884040","id":"PMC_2884040","title":"Expression of the v-erbA oncogene in chicken embryo fibroblasts stimulates their proliferation in vitro and enhances tumor growth in vivo.","date":"1987","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/2884040","citation_count":113,"is_preprint":false},{"pmid":"1850510","id":"PMC_1850510","title":"Genomic organization of the human thyroid hormone receptor alpha (c-erbA-1) gene.","date":"1991","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/1850510","citation_count":106,"is_preprint":false},{"pmid":"6328658","id":"PMC_6328658","title":"Sequencing the erbA gene of avian erythroblastosis virus reveals a new type of oncogene.","date":"1984","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/6328658","citation_count":103,"is_preprint":false},{"pmid":"8098843","id":"PMC_8098843","title":"A conserved C-terminal sequence that is deleted in v-ErbA is essential for the biological activities of c-ErbA (the thyroid hormone receptor).","date":"1993","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/8098843","citation_count":102,"is_preprint":false},{"pmid":"12082618","id":"PMC_12082618","title":"Expression of thyroid hormone receptor/erbA genes is altered in human breast cancer.","date":"2002","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/12082618","citation_count":98,"is_preprint":false},{"pmid":"2568887","id":"PMC_2568887","title":"Expression of the v-erbA product, an altered nuclear hormone receptor, is sufficient to transform erythrocytic cells in vitro.","date":"1989","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/2568887","citation_count":98,"is_preprint":false},{"pmid":"10704394","id":"PMC_10704394","title":"Increased cell death and delayed development in the cerebellum of mice lacking the rev-erbA(alpha) orphan receptor.","date":"2000","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/10704394","citation_count":97,"is_preprint":false},{"pmid":"2884103","id":"PMC_2884103","title":"A single point mutation in erbA restores the erythroid transforming potential of a mutant avian erythroblastosis virus (AEV) defective in both erbA and erbB oncogenes.","date":"1987","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/2884103","citation_count":92,"is_preprint":false},{"pmid":"8096810","id":"PMC_8096810","title":"Unliganded T3R, but not its oncogenic variant, v-erbA, suppresses RAR-dependent transactivation by titrating out RXR.","date":"1993","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/8096810","citation_count":92,"is_preprint":false},{"pmid":"1682217","id":"PMC_1682217","title":"v-erbA overexpression is required to extinguish c-erbA function in erythroid cell differentiation and regulation of the erbA target gene CAII.","date":"1991","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/1682217","citation_count":89,"is_preprint":false},{"pmid":"1979040","id":"PMC_1979040","title":"Phosphorylation of the v-erbA protein is required for its function as an oncogene.","date":"1990","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/1979040","citation_count":89,"is_preprint":false},{"pmid":"1979758","id":"PMC_1979758","title":"The viral erbA oncogene protein, a constitutive repressor in animal cells, is a hormone-regulated activator in yeast.","date":"1990","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/1979758","citation_count":87,"is_preprint":false},{"pmid":"7003595","id":"PMC_7003595","title":"Nucleotide sequence of the thrA gene of Escherichia coli.","date":"1980","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/7003595","citation_count":86,"is_preprint":false},{"pmid":"2552374","id":"PMC_2552374","title":"The c-erbA alpha-encoded thyroid hormone receptor is phosphorylated in its amino terminal domain by casein kinase II.","date":"1989","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/2552374","citation_count":86,"is_preprint":false},{"pmid":"8614403","id":"PMC_8614403","title":"Constitutive expression of the orphan receptor, Rev-erbA alpha, inhibits muscle differentiation and abrogates the expression of the myoD gene family.","date":"1995","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/8614403","citation_count":85,"is_preprint":false},{"pmid":"2572268","id":"PMC_2572268","title":"c-erbB-2/c-erbA co-amplification indicative of lymph node metastasis, and c-myc amplification of high tumour grade, in human breast carcinoma.","date":"1989","source":"British journal of cancer","url":"https://pubmed.ncbi.nlm.nih.gov/2572268","citation_count":81,"is_preprint":false},{"pmid":"8948627","id":"PMC_8948627","title":"Two receptor interaction domains in the corepressor, N-CoR/RIP13, are required for an efficient interaction with Rev-erbA alpha and RVR: physical association is dependent on the E region of the orphan receptors.","date":"1996","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/8948627","citation_count":79,"is_preprint":false},{"pmid":"8385673","id":"PMC_8385673","title":"Thyroid hormone receptor/c-erbA: control of commitment and differentiation in the neuronal/chromaffin progenitor line PC12.","date":"1993","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/8385673","citation_count":76,"is_preprint":false},{"pmid":"7910550","id":"PMC_7910550","title":"v-erbA and citral reduce the teratogenic effects of all-trans retinoic acid and retinol, respectively, in Xenopus embryogenesis.","date":"1993","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/7910550","citation_count":76,"is_preprint":false},{"pmid":"7925269","id":"PMC_7925269","title":"Thyroid abnormalities and hepatocellular carcinoma in mice transgenic for v-erbA.","date":"1994","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/7925269","citation_count":76,"is_preprint":false},{"pmid":"2901667","id":"PMC_2901667","title":"Regulation of two c-erbA messenger ribonucleic acids in rat GH3 cells by thyroid hormone.","date":"1988","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/2901667","citation_count":72,"is_preprint":false},{"pmid":"1693571","id":"PMC_1693571","title":"Characterization of site-specific polyclonal antibodies to c-erbA peptides recognizing human thyroid hormone receptors alpha 1, alpha 2, and beta and native 3,5,3'-triiodothyronine receptor, and study of tissue distribution of the antigen.","date":"1990","source":"Endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/1693571","citation_count":72,"is_preprint":false},{"pmid":"25670821","id":"PMC_25670821","title":"Thyroid hormone resistance syndrome due to mutations in the thyroid hormone receptor α gene (THRA).","date":"2015","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/25670821","citation_count":70,"is_preprint":false},{"pmid":"3054510","id":"PMC_3054510","title":"c-erbA encodes multiple proteins in chicken erythroid cells.","date":"1988","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/3054510","citation_count":68,"is_preprint":false},{"pmid":"1846005","id":"PMC_1846005","title":"A new point mutation in the 3,5,3'-triiodothyronine-binding domain of the c-erbA beta thyroid hormone receptor is tightly linked to generalized thyroid hormone resistance.","date":"1991","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/1846005","citation_count":67,"is_preprint":false},{"pmid":"8381821","id":"PMC_8381821","title":"An arginine to histidine mutation in codon 311 of the C-erbA beta gene results in a mutant thyroid hormone receptor that does not mediate a dominant negative phenotype.","date":"1993","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/8381821","citation_count":66,"is_preprint":false},{"pmid":"2891438","id":"PMC_2891438","title":"erbA-related sequence coding for DNA-binding hormone receptor localized to chromosome 3p21-3p25 and deleted in small cell lung carcinoma.","date":"1988","source":"Cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/2891438","citation_count":62,"is_preprint":false},{"pmid":"7906409","id":"PMC_7906409","title":"c-erbA alpha/T3R and RARs control commitment of hematopoietic self-renewing progenitor cells to apoptosis or differentiation and are antagonized by the v-erbA oncogene.","date":"1994","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/7906409","citation_count":61,"is_preprint":false},{"pmid":"7902566","id":"PMC_7902566","title":"Identification of a domain required for oncogenic activity and transcriptional suppression by v-erbA and thyroid-hormone receptor alpha.","date":"1993","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/7902566","citation_count":60,"is_preprint":false},{"pmid":"1675637","id":"PMC_1675637","title":"Thyroid hormone receptor/and v-erbA. A single amino acid difference in the C-terminal region influences dominant negative activity and receptor dimer formation.","date":"1991","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/1675637","citation_count":60,"is_preprint":false},{"pmid":"10921888","id":"PMC_10921888","title":"Targeting of N-CoR and histone deacetylase 3 by the oncoprotein v-erbA yields a chromatin infrastructure-dependent transcriptional repression pathway.","date":"2000","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/10921888","citation_count":59,"is_preprint":false},{"pmid":"2464752","id":"PMC_2464752","title":"Characterization of the domain structure of chick c-erbA by deletion mutation: in vitro translation and cell transfection studies.","date":"1989","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/2464752","citation_count":57,"is_preprint":false},{"pmid":"8105369","id":"PMC_8105369","title":"The erbA oncogene represses the actions of both retinoid X and retinoid A receptors but does so by distinct mechanisms.","date":"1993","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/8105369","citation_count":56,"is_preprint":false},{"pmid":"10809233","id":"PMC_10809233","title":"Structure-function analysis of the Rev-erbA and RVR ligand-binding domains reveals a large hydrophobic surface that mediates corepressor binding and a ligand cavity occupied by side chains.","date":"2000","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/10809233","citation_count":55,"is_preprint":false},{"pmid":"1645454","id":"PMC_1645454","title":"Regulation of c-erbA-alpha messenger RNA species in tadpole erythrocytes by thyroid hormone.","date":"1991","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/1645454","citation_count":54,"is_preprint":false},{"pmid":"1347913","id":"PMC_1347913","title":"The v-erbA oncogene requires cooperation with tyrosine kinases to arrest erythroid differentiation induced by ligand-activated endogenous c-erbA and retinoic acid receptor.","date":"1992","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/1347913","citation_count":53,"is_preprint":false},{"pmid":"1656222","id":"PMC_1656222","title":"The thyroid hormone receptor gene (c-erbA alpha) is expressed in advance of thyroid gland maturation during the early embryonic development of Xenopus laevis.","date":"1991","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/1656222","citation_count":51,"is_preprint":false},{"pmid":"2553781","id":"PMC_2553781","title":"Expression of the ErbA-beta class of thyroid hormone receptors is selectively lost in human colon carcinoma.","date":"1989","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/2553781","citation_count":50,"is_preprint":false},{"pmid":"26037512","id":"PMC_26037512","title":"A Novel Mutation in THRA Gene Associated With an Atypical Phenotype of Resistance to Thyroid Hormone.","date":"2015","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/26037512","citation_count":47,"is_preprint":false},{"pmid":"2826814","id":"PMC_2826814","title":"The avian erythroblastosis virus erbA oncogene encodes a DNA-binding protein exhibiting distinct nuclear and cytoplasmic subcellular localizations.","date":"1988","source":"Journal of virology","url":"https://pubmed.ncbi.nlm.nih.gov/2826814","citation_count":47,"is_preprint":false},{"pmid":"8093812","id":"PMC_8093812","title":"V-erbA requires auxiliary proteins for dominant negative activity.","date":"1993","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/8093812","citation_count":47,"is_preprint":false},{"pmid":"1975094","id":"PMC_1975094","title":"The lack of transcriptional activation of the v-erbA oncogene is in part due to a mutation present in the DNA binding domain of the protein.","date":"1990","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/1975094","citation_count":44,"is_preprint":false},{"pmid":"1318505","id":"PMC_1318505","title":"The unique C-termini of the thyroid hormone receptor variant, c-erbA alpha 2, and thyroid hormone receptor alpha 1 mediate different DNA-binding and heterodimerization properties.","date":"1992","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/1318505","citation_count":44,"is_preprint":false},{"pmid":"1672166","id":"PMC_1672166","title":"Ontogeny of the v-erbA oncoprotein from the thyroid hormone receptor: an alteration in the DNA binding domain plays a role crucial for v-erbA function.","date":"1991","source":"Journal of virology","url":"https://pubmed.ncbi.nlm.nih.gov/1672166","citation_count":42,"is_preprint":false},{"pmid":"1971514","id":"PMC_1971514","title":"Isolation of a cDNA encoding human Rev-ErbA alpha: transcription from the noncoding DNA strand of a thyroid hormone receptor gene results in a related protein that does not bind thyroid hormone.","date":"1990","source":"DNA and cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/1971514","citation_count":41,"is_preprint":false},{"pmid":"11726557","id":"PMC_11726557","title":"Suppression of the deafness and thyroid dysfunction in Thrb-null mice by an independent mutation in the Thra thyroid hormone receptor alpha gene.","date":"2001","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/11726557","citation_count":40,"is_preprint":false},{"pmid":"2160381","id":"PMC_2160381","title":"Expression of erbA alpha and beta mRNAs in regions of adult rat brain.","date":"1990","source":"Molecular and cellular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/2160381","citation_count":40,"is_preprint":false},{"pmid":"3036525","id":"PMC_3036525","title":"Nucleotide sequence of the chicken proto-oncogene c-erbA corresponding to domain 1 of v-erbA.","date":"1987","source":"European journal of biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/3036525","citation_count":40,"is_preprint":false},{"pmid":"9482666","id":"PMC_9482666","title":"Identification and characterization of a novel corepressor interaction region in RVR and Rev-erbA alpha.","date":"1998","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/9482666","citation_count":39,"is_preprint":false},{"pmid":"7904604","id":"PMC_7904604","title":"Roles of v-erbA homodimers and heterodimers in mediating dominant negative activity by v-erbA.","date":"1994","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/7904604","citation_count":38,"is_preprint":false},{"pmid":"2847034","id":"PMC_2847034","title":"Genetic dissection of functional domains within the avian erythroblastosis virus v-erbA oncogene.","date":"1988","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/2847034","citation_count":38,"is_preprint":false},{"pmid":"2169728","id":"PMC_2169728","title":"Thyroid hormone and DNA binding properties of a mutant c-erbA beta receptor associated with generalized thyroid hormone resistance.","date":"1990","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/2169728","citation_count":37,"is_preprint":false},{"pmid":"9917326","id":"PMC_9917326","title":"Hepatocyte nuclear factor 4-mediated activation of rat CYP3A1 gene and its modes of modulation by apolipoprotein AI regulatory protein I and v-ErbA-related protein 3.","date":"1999","source":"Archives of biochemistry and biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/9917326","citation_count":37,"is_preprint":false},{"pmid":"10493974","id":"PMC_10493974","title":"The v-erbA oncogene (review).","date":"1999","source":"International journal of molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/10493974","citation_count":35,"is_preprint":false},{"pmid":"30500912","id":"PMC_30500912","title":"Bisphenol A Alters Bmal1, Per2, and Rev-Erba mRNA and Requires Bmal1 to Increase Neuropeptide Y Expression in Hypothalamic Neurons.","date":"2019","source":"Endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/30500912","citation_count":35,"is_preprint":false},{"pmid":"1968105","id":"PMC_1968105","title":"Sequence-specific DNA binding by the v-erbA oncogene protein of avian erythroblastosis virus.","date":"1990","source":"Journal of virology","url":"https://pubmed.ncbi.nlm.nih.gov/1968105","citation_count":33,"is_preprint":false},{"pmid":"1349165","id":"PMC_1349165","title":"V-erbA and c-erbA proteins enhance transcriptional activation by c-jun.","date":"1992","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/1349165","citation_count":31,"is_preprint":false},{"pmid":"8134111","id":"PMC_8134111","title":"Unliganded c-erbA/thyroid hormone receptor induces trkB expression in neuroblastoma cells.","date":"1994","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/8134111","citation_count":31,"is_preprint":false},{"pmid":"1314846","id":"PMC_1314846","title":"An arginine to histidine mutation in codon 315 of the c-erbA beta thyroid hormone receptor in a kindred with generalized resistance to thyroid hormones results in a receptor with significant 3,5,3'-triiodothyronine binding activity.","date":"1992","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/1314846","citation_count":31,"is_preprint":false},{"pmid":"2904357","id":"PMC_2904357","title":"Antipeptide antibodies recognize c-erbA and a related protein in human A431 carcinoma cells.","date":"1988","source":"Endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/2904357","citation_count":30,"is_preprint":false},{"pmid":"2126201","id":"PMC_2126201","title":"The carbonic anhydrase II gene, a gene regulated by thyroid hormone and erythropoietin, is repressed by the v-erbA oncogene in erythrocytic cells.","date":"1990","source":"The New biologist","url":"https://pubmed.ncbi.nlm.nih.gov/2126201","citation_count":30,"is_preprint":false},{"pmid":"1969136","id":"PMC_1969136","title":"Requirement for the C-terminal domain of the v-erbA oncogene protein for biological function and transcriptional repression.","date":"1990","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/1969136","citation_count":29,"is_preprint":false},{"pmid":"7796935","id":"PMC_7796935","title":"Modulation of thyroid hormone action by mutant thyroid hormone receptors, c-erbA alpha 2 and peroxisome proliferator-activated receptor: evidence for different mechanisms of inhibition.","date":"1995","source":"Molecular and cellular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/7796935","citation_count":29,"is_preprint":false},{"pmid":"1967151","id":"PMC_1967151","title":"A subpopulation of the avian erythroblastosis virus v-erbA protein, a member of the nuclear hormone receptor family, is glycosylated.","date":"1990","source":"Journal of virology","url":"https://pubmed.ncbi.nlm.nih.gov/1967151","citation_count":28,"is_preprint":false},{"pmid":"9100577","id":"PMC_9100577","title":"Deoxyribonucleic acid binding and transcriptional silencing by a truncated c-erbA beta 1 thyroid hormone receptor identified in a severely retarded patient with resistance to thyroid hormone.","date":"1997","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/9100577","citation_count":26,"is_preprint":false},{"pmid":"9264411","id":"PMC_9264411","title":"Mechanism of transformation by v-ErbA: substitution for steroid hormone receptor function in self renewal induction.","date":"1997","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/9264411","citation_count":25,"is_preprint":false},{"pmid":"8093487","id":"PMC_8093487","title":"v-erbA acts on retinoic acid receptors in immature avian erythroid cells.","date":"1993","source":"Journal of virology","url":"https://pubmed.ncbi.nlm.nih.gov/8093487","citation_count":24,"is_preprint":false},{"pmid":"2158623","id":"PMC_2158623","title":"The chicken c-erbA alpha-product induces expression of thyroid hormone-responsive genes in 3,5,3'-triiodothyronine receptor-deficient rat hepatoma cells.","date":"1990","source":"Molecular endocrinology (Baltimore, Md.)","url":"https://pubmed.ncbi.nlm.nih.gov/2158623","citation_count":24,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":46806,"output_tokens":8144,"usd":0.131289,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":17796,"output_tokens":5394,"usd":0.111915,"stage2_stop_reason":"end_turn"},"total_usd":0.243204,"stage1_batch_id":"msgbatch_017qqVz33Ga63SCDwzb35XPb","stage2_batch_id":"msgbatch_01Scr2Ei9x4HJMiRGxwrmvLK","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1989,\n      \"finding\": \"TRα1 (c-erbA alpha 1) functions as a ligand-dependent transcriptional activator of thyroid hormone-responsive genes, while the alternatively spliced variant TRα2 (c-erbA alpha 2) does not bind T3 but inhibits T3-dependent gene induction mediated by TRα1 or TRβ, establishing dominant-negative antagonism through alternative splicing of the same locus.\",\n      \"method\": \"Transient transfection of T3-responsive reporter genes in mammalian cells; in vitro translation and ligand-binding assays\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — multiple independent labs (Koenig et al. PMID:2537467; Lazar et al. PMID:2903438; Lazar et al. PMID:2554288) replicated using in vitro binding, reporter assays, and mutagenesis\",\n      \"pmids\": [\"2537467\", \"2903438\", \"2554288\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"The v-erbA oncogene protein acts as a constitutive transcriptional repressor of thyroid hormone-responsive promoters and, when co-expressed with c-erbA/TRα, blocks T3-dependent transcriptional activation, establishing v-erbA as a dominant-negative oncogene that antagonizes its cellular homolog.\",\n      \"method\": \"Co-transfection of v-erbA and c-erbA expression vectors with T3-responsive reporter genes in cell lines; functional transcriptional assays\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — replicated across multiple labs using reporter assays, chimeric protein analysis, and erythroid differentiation assays (PMID:2733791, PMID:1972036, PMID:1682217)\",\n      \"pmids\": [\"2733791\", \"1972036\", \"1682217\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1988,\n      \"finding\": \"The hormone-binding domain of c-erbA/TRα resides in the carboxy-terminal half of the protein; multiple mutations in this region of v-erbA cooperate to abolish T3 binding, and the ligand-binding domain is positionally analogous to that of steroid receptors.\",\n      \"method\": \"Chimeric v-erbA/c-erbA protein analysis; ligand-binding assays of in vitro translated deletion and chimeric mutants\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with systematic mutagenesis of chimeras; replicated by multiple deletion studies (PMID:3359993, PMID:2464752)\",\n      \"pmids\": [\"3359993\", \"2464752\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1988,\n      \"finding\": \"c-erbA/TRα protein (p46c-erbA) is phosphorylated on serine residues in its amino-terminal domain; one site (Ser28/Ser29) is shared with v-erbA and phosphorylation is enhanced 10-fold by activators of PKC or PKA; cAMP-dependent protein kinase directly phosphorylates both proteins in vitro at this site.\",\n      \"method\": \"In vivo metabolic labeling, tryptic phosphopeptide mapping, in vitro kinase assays with purified cAMP-dependent protein kinase\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro kinase reconstitution plus in vivo phosphopeptide mapping, two orthogonal methods in one study (PMID:2903825)\",\n      \"pmids\": [\"2903825\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"c-erbA/TRα is phosphorylated at Ser12 in its amino-terminal domain by casein kinase II; the site contains an acidic context matching CK2 consensus; purified CK2 phosphorylates c-erbA at the same site in vitro; Ser12→Ala mutation abolishes CK2 phosphorylation in vitro.\",\n      \"method\": \"In vitro phosphorylation with purified casein kinase II; site-directed mutagenesis (Ser12→Ala); two-dimensional phosphopeptide mapping\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with mutagenesis and 2D peptide mapping in a single focused study (PMID:2552374)\",\n      \"pmids\": [\"2552374\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"Phosphorylation of Ser-16/17 in the v-erbA-encoded domain of the gag/v-erbA fusion protein is required for its oncogenic function: Ser→Ala substitutions at these positions abolish phosphorylation, block inhibition of erythroid differentiation, and prevent suppression of erythrocyte-specific genes (band 3, CAII), while Ser→Thr substitution preserves basal but not PKA/PKC-enhanced phosphorylation and gives partial activity.\",\n      \"method\": \"Site-directed mutagenesis of Ser-16/17; retroviral expression in ts-v-erbB or ts-v-sea erythroblasts; in vivo and in vitro phosphorylation analysis; differentiation and gene expression assays\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — systematic mutagenesis with multiple orthogonal readouts (phosphorylation, differentiation, gene expression) in one rigorous study (PMID:1979040)\",\n      \"pmids\": [\"1979040\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"A conserved 9-amino-acid sequence at the extreme C-terminus of c-ErbA alpha (deleted in v-ErbA) is essential for T3-dependent transcriptional activation, AP-1 transcriptional interference, and induction of erythroid differentiation; single, double, and triple amino acid substitutions within this region abolish both transactivation and AP-1 interference independently of their effect on T3 binding.\",\n      \"method\": \"c-ErbA/v-ErbA chimeras; site-directed mutagenesis; transient transfection reporter assays; erythroid differentiation assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — systematic mutagenesis with three independent functional readouts in one rigorous study (PMID:8098843)\",\n      \"pmids\": [\"8098843\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1991,\n      \"finding\": \"c-ErbA alpha (TRα1) represses AP-1-mediated transcriptional activation of the collagenase gene promoter by decreasing AP-1 activity in a ligand-activated manner; v-ErbA fails to repress AP-1 and acts as a dominant negative by overcoming c-ErbA alpha-mediated AP-1 repression, thereby abrogating growth-inhibitory responses to retinoic acid.\",\n      \"method\": \"Co-transfection of AP-1 reporter constructs with c-ErbA alpha or v-ErbA expression vectors; AP-1 activity assays; growth assays in chicken embryo fibroblasts with retinoic acid\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reporter assays plus growth phenotype, single lab with two orthogonal methods (PMID:1682056)\",\n      \"pmids\": [\"1682056\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"Unliganded TRα (c-ErbA alpha), but not v-ErbA, suppresses RAR-dependent transactivation by competing for the shared dimerization partner RXR; TRα/RXR competition dissociates preformed RAR/RXR–RARE ternary complexes in vitro; a single Pro349→Ser mutation in v-ErbA's dimerization interface abolishes this trans-dominant phenotype when introduced into TRα.\",\n      \"method\": \"Gel-shift (EMSA) showing dissociation of RAR/RXR–RARE complex; co-transfection with RXR to alleviate suppression; site-directed mutagenesis of dimerization interface\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro EMSA reconstitution plus mutagenesis plus co-transfection rescue, multiple orthogonal methods in one study (PMID:8096810)\",\n      \"pmids\": [\"8096810\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"v-ErbA requires heterodimerization with RXR-alpha for sufficient DNA binding to natural thyroid hormone response elements; only v-ErbA–RXR-alpha heterodimers bind TREs with the affinity required for potent transcriptional repression; C-terminal mutations that abolish v-ErbA–RXR-alpha heterodimerization also abolish repressor activity.\",\n      \"method\": \"EMSA heterodimerization assays; co-transfection with dominant-negative RXR; C-terminal mutagenesis of v-ErbA\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — EMSA reconstitution plus mutagenesis plus reporter assays, multiple methods in one study (PMID:8093812)\",\n      \"pmids\": [\"8093812\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"c-ErbA alpha (TRα1) activates transcription through an RSV-LTR T3 response element (RSV-T3RE) in the absence of ligand via a unique N-terminal activation domain; T3 reverses this ligand-independent activation; c-ErbA alpha/RXR heterodimers or c-ErbA alpha homodimers recognize this element; c-ErbA alpha adopts a different conformation on RSV-T3RE versus classical T3RE, enabling selective deployment of N-terminal vs. C-terminal activation domains.\",\n      \"method\": \"Transient transfection of RSV-T3RE reporter with c-ErbA alpha domain mutants; EMSA; N-terminal deletion analysis\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — reporter assays with domain mutants plus EMSA, two orthogonal methods in one study (PMID:7903219)\",\n      \"pmids\": [\"7903219\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"A 'hinge-region' Pro→Arg mutation in v-ErbA (equivalent to TRα hinge) selectively abolishes transcriptional repression (trans-repression) without affecting DNA binding or hormone binding of TRα, suggesting that trans-repression—not dominant-negative blockade of receptor activation—is the primary oncogenic function of v-erbA.\",\n      \"method\": \"Site-directed mutagenesis of hinge Pro→Arg in v-ErbA and TRα; co-transfection reporter assays; T3 and retinoic acid response assays\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mutagenesis plus multiple reporter assays with selective functional dissection in one study (PMID:7902566)\",\n      \"pmids\": [\"7902566\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"A DNA-binding mutation (Gly73→Ser) in the zinc-finger domain of v-ErbA is in part responsible for its inability to activate transcription; chimeric ER/TRα constructs with the v-erbA DNA-binding domain fail to activate reporters, whereas those with the c-erbA DNA-binding domain activate transcription.\",\n      \"method\": \"Chimeric estrogen/thyroid hormone receptor constructs; transient co-transfection reporter assays\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — chimeric receptor reporter assays, single lab, single method (PMID:1975094)\",\n      \"pmids\": [\"1975094\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1991,\n      \"finding\": \"v-ErbA and c-ErbA both bind directly to sequences within the CAII (carbonic anhydrase II) promoter; this erbA-binding site confers T3 responsiveness to a heterologous promoter; v-ErbA requires overexpression to overcome c-ErbA/T3-mediated activation at equimolar ratios in stably transformed erythroblasts.\",\n      \"method\": \"DNA-protein binding assays (EMSA/footprinting); stable retroviral co-expression of v-erbA and c-erbA; T3-responsive reporter and endogenous gene expression assays\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct DNA binding plus stable gene expression analysis plus reporter assays, multiple orthogonal methods (PMID:1682217)\",\n      \"pmids\": [\"1682217\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1988,\n      \"finding\": \"c-erbA/TRα1 protein and in vitro-translated c-erbA products are localized predominantly to the nucleus; multiple c-erbA-encoded proteins of 27–46 kDa arise from internal initiations within the c-erbA mRNA, generating a nested set of proteins; all are nuclear.\",\n      \"method\": \"Anti-erbA antibodies; immunoprecipitation; subcellular fractionation; in vitro translation; partial proteolytic mapping\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — fractionation, in vitro translation, and immunoprecipitation in a single study with multiple methods (PMID:3054510)\",\n      \"pmids\": [\"3054510\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1988,\n      \"finding\": \"c-erbA alpha and c-erbA beta proteins mediate thyroid hormone-dependent regulation of the rat growth hormone and prolactin gene regulatory sequences, functioning as T3 receptors; in receptor-deficient cells both act as hormone-dependent modulators, confirming their identity as functional T3 receptors.\",\n      \"method\": \"Transient expression of c-erbA alpha and c-erbA beta with chimeric GH/PRL reporter constructs in receptor-deficient (235-1) and receptor-containing (GH4C1, GH1) cell lines\",\n      \"journal\": \"Molecular endocrinology (Baltimore, Md.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-line complementation with receptor-deficient cells plus multiple receptor subtypes and promoters, single lab but rigorous design (PMID:2903439)\",\n      \"pmids\": [\"2903439\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"The chicken c-erbA alpha protein restores T3 responsiveness (malic enzyme, PEPCK, Na+/K+-ATPase gene induction and direct activation of MLV promoter) in FAO receptor-deficient hepatoma cells in a ligand-dependent manner, proving it is a functional T3 receptor.\",\n      \"method\": \"Retroviral expression of cTR-alpha in FAO cells; Northern blot analysis of T3-responsive endogenous genes; T3 dose-response experiments\",\n      \"journal\": \"Molecular endocrinology (Baltimore, Md.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell complementation with multiple endogenous gene readouts, single lab (PMID:2158623)\",\n      \"pmids\": [\"2158623\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"Overexpressed TRα (c-erbA/T3 receptor) modulates erythroid differentiation and erythrocyte-specific gene expression in a T3-dependent fashion in erythroid cells; v-erbA has lost the T3-dependent regulatory activity but constitutively displays a repressor function; the region responsible for loss of hormone-dependent activity in v-erbA maps to the extreme C-terminus of c-erbA, including a cluster of conserved residues forming a predicted amphipathic alpha-helix.\",\n      \"method\": \"Retroviral expression of chimeric v-/c-erbA proteins in erythroid cells; erythroid differentiation assays; erythrocyte gene expression analysis\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — chimeric protein mapping in cells with differentiation and gene expression readouts, replicated concept across labs (PMID:1972036, PMID:8098843)\",\n      \"pmids\": [\"1972036\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Rev-ErbA alpha (encoded on the opposite strand of the THRA locus) physically interacts with the corepressor N-CoR/RIP13 through a domain composed of two receptor interaction domains (ID-I and ID-II); this interaction requires an intact E (ligand-binding) region of Rev-ErbA alpha; overexpression of N-CoR interaction domains relieves Rev-ErbA alpha-mediated repression.\",\n      \"method\": \"Mammalian two-hybrid system; co-transfection repression assays with dominant-negative N-CoR fragments; deletion mutagenesis of Rev-ErbA alpha E region\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — two-hybrid and co-transfection assays, single lab, two orthogonal methods (PMID:8948627)\",\n      \"pmids\": [\"8948627\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"v-ErbA recruits both N-CoR and HDAC3 to chromatin for transcriptional repression, but—unlike TRα—requires mature chromatin (not partial chromatinization) for this repression; v-ErbA is less competent than TRα for binding TFIIB in vitro and in vivo, explaining its impaired silencing on partly chromatinized templates.\",\n      \"method\": \"Xenopus oocyte chromatin assembly assays; histone deacetylase inhibitor (TSA) treatment; co-immunoprecipitation of N-CoR and HDAC3; in vitro TFIIB binding assays\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — Xenopus oocyte reconstitution plus Co-IP plus in vitro binding, multiple orthogonal methods in one study (PMID:10921888)\",\n      \"pmids\": [\"10921888\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1991,\n      \"finding\": \"The antisense RNA Rev-ErbA alpha (transcribed from the opposite strand of the THRA locus) inhibits splicing of c-erbA alpha 2 pre-mRNA in vitro; both an antisense RNA spanning the 3′ splice site and a shorter exon-complementary RNA block splicing, suggesting that base-pairing with Rev-ErbA alpha shifts the alpha1/alpha2 ratio by inhibiting alpha2 mRNA splicing.\",\n      \"method\": \"In vitro splicing assay with c-erbA alpha 2 pre-mRNA; addition of antisense Rev-ErbA alpha RNA fragments; competition with non-complementary RNAs as control\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution of splicing inhibition with strand-specific controls, single lab (PMID:1657988)\",\n      \"pmids\": [\"1657988\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"The unique C-terminus of TRα1 is required for heterodimerization with nuclear proteins on T3-response elements; the unique C-terminus of c-erbA alpha 2 acts as an inhibitory domain reducing DNA binding; chimera experiments show the last 100–150 aa of TRα1 are sufficient to confer heterodimerization competence on alpha 2.\",\n      \"method\": \"In vitro synthesis in E. coli and reticulocyte lysates; EMSA with TR alpha 1, alpha 2, and C-terminal deletion/chimeric mutants; heterodimerization assays on TREs\",\n      \"journal\": \"Molecular endocrinology (Baltimore, Md.)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with systematic chimeric and deletion mutants, EMSA, single lab (PMID:1318505)\",\n      \"pmids\": [\"1318505\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"Unliganded TRα1 (c-erbA alpha) expressed in PC12 neuronal progenitor cells inhibits NGF-induced neuronal differentiation and represses neuron-specific gene expression; T3 binding relieves this inhibition, allowing normal differentiation; TRα1 also constitutively blocks dexamethasone-induced chromaffin differentiation, establishing TRα1 as a ligand-controlled switch for neuronal vs. chromaffin progenitor commitment.\",\n      \"method\": \"Retroviral expression of c-erbA/TR alpha-1 or v-erbA in PC12 cells; NGF and dexamethasone differentiation assays; neuronal gene expression analysis\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean gain-of-function in a defined cell line with multiple differentiation readouts and hormone dose-response, single lab (PMID:8385673)\",\n      \"pmids\": [\"8385673\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"Unliganded TRα1 induces trkB mRNA expression (with concomitant loss of trkA and trkC) in N2a neuroblastoma cells in a ligand-independent manner; both TRα1 and TRβ1 produce this effect upon transient expression.\",\n      \"method\": \"Stable and transient expression of c-erbA/TR alpha 1 in N2a cells; Northern blot analysis of trk mRNAs; T3 treatment (no effect); tyrosine phosphorylation assay of induced gp145trkB\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — gene expression assay with functional protein validation, single lab, single main method (PMID:8134111)\",\n      \"pmids\": [\"8134111\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Two novel N-terminally truncated isoforms of TRα (TRΔα1 and TRΔα2) are transcribed from an internal promoter within intron 7 of the c-erbA alpha gene; TRΔα1 antagonizes T3-dependent and retinoic-acid-dependent transcriptional activation by TRα1 and 9-cis-RAR alpha but does not affect RAR alpha-dependent activation.\",\n      \"method\": \"Identification of internal promoter by 5′ RACE; expression vector transfection; T3- and RA-responsive reporter assays with TRΔα1 co-expression\",\n      \"journal\": \"Molecular endocrinology (Baltimore, Md.)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — promoter identification plus reporter co-transfection with selective inhibition profile, single lab (PMID:9259319)\",\n      \"pmids\": [\"9259319\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"A targeted mutation in Thra (Thra(tm2)) that deletes TRα2 and causes overexpression of TRα1 suppresses the deafness and thyroid hyperactivity phenotypes of Thrb-null mice, indicating that increased TRα1 expression can substitute for loss of TRβ and that TRα2 is dispensable for hearing.\",\n      \"method\": \"Genetic epistasis: Thra(tm2) allele introduced into Thrb(tm1/tm1) null background; auditory brainstem response thresholds; thyroid hormone measurements\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic epistasis in mice with two independent phenotypic readouts (hearing, thyroid), single lab (PMID:11726557)\",\n      \"pmids\": [\"11726557\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Truncating and missense mutations in THRA cause a distinct resistance-to-thyroid-hormone syndrome (RTHα) with low fT4/fT3 ratio, macrocephaly, and skeletal dysplasia; missense mutations show milder phenotypes than truncating mutations (genotype-phenotype correlation), establishing THRA as the causal gene.\",\n      \"method\": \"Whole exome sequencing followed by Sanger sequencing; longitudinal clinical assessment; biochemical thyroid function tests in six patients from five families\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — human genetic causation established by sequencing in multiple independent families with consistent phenotype, but no in vitro functional assay in this paper (PMID:25670821)\",\n      \"pmids\": [\"25670821\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"A de novo missense mutation in THRA (N359Y) affecting TRα1 causes decreased T3 binding affinity and a dominant-negative effect on wild-type TRα1-mediated transcription; the mutation also affects the non-receptor isoform TRα2.\",\n      \"method\": \"Whole exome sequencing; in vitro transcriptional activity assays of mutant vs. wild-type TRα1; T3 binding assays; dominant-negative co-transfection assays\",\n      \"journal\": \"The Journal of clinical endocrinology and metabolism\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — functional assays (T3 binding, reporter, dominant-negative) on a single patient mutation, single lab (PMID:26037512)\",\n      \"pmids\": [\"26037512\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1988,\n      \"finding\": \"v-ErbA protein exists in both nuclear and cytoplasmic forms; both forms can bind DNA; a mutation that inhibits DNA binding also inhibits nuclear localization and abolishes the ability to potentiate erythroid transformation, linking DNA binding to nuclear localization and oncogenic function.\",\n      \"method\": \"Site-specific antisera; subcellular fractionation; DNA binding assays; biological transformation assays\",\n      \"journal\": \"Journal of virology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — fractionation, DNA binding, and transformation assays with DNA-binding mutant, single lab (PMID:2826814)\",\n      \"pmids\": [\"2826814\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"A subpopulation of the v-erbA protein (a TRα-derived nuclear receptor) is glycosylated, identifying TRα-related proteins as members of the glycoprotein class of nuclear transcription factors.\",\n      \"method\": \"Metabolic labeling with [3H]-glucosamine; glycosidase treatment; immunoprecipitation\",\n      \"journal\": \"Journal of virology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single biochemical observation in v-erbA (surrogate for TRα), single method, single lab (PMID:1967151)\",\n      \"pmids\": [\"1967151\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"ErbA oncogene protein (v-ErbA) interferes with TRα and trans-retinoic acid receptors by competing for binding to their respective DNA response elements; v-ErbA does not heterodimerize with RAR or TR in a functionally significant manner for repression of these receptors, but efficiently heterodimerizes with RXR, which dramatically impairs RXR-mediated gene activation.\",\n      \"method\": \"EMSA competition assays; co-transfection reporter assays; heterodimerization assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — EMSA plus reporter assays, single lab with two methods (PMID:8105369)\",\n      \"pmids\": [\"8105369\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"THRA encodes thyroid hormone receptor alpha (TRα1), a ligand-dependent nuclear transcription factor that, upon T3 binding, activates T3-responsive genes via thyroid hormone response elements (TREs); in the absence of T3, unliganded TRα1 represses target genes by recruiting corepressors (N-CoR/HDAC3); an alternatively spliced isoform TRα2 lacks T3 binding and acts as a dominant-negative inhibitor of TRα1 by competing for TREs while being unable to heterodimerize; additional N-terminally truncated isoforms (TRΔα1/2) from an internal promoter further attenuate receptor activity; TRα1 is phosphorylated at Ser12 by casein kinase II and at Ser28/29 by PKA/PKC, modulating its transcriptional function; the extreme C-terminal helix AF-2 is essential for T3-dependent transactivation, AP-1 interference, and erythroid differentiation; germline THRA loss-of-function or dominant-negative mutations cause resistance to thyroid hormone alpha (RTHα) with growth retardation, skeletal dysplasia, and low fT4/fT3 ratio, while overexpression of TRα1 can compensate for loss of TRβ in auditory and thyroid function.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"THRA encodes thyroid hormone receptor alpha (TRα1, c-erbA alpha 1), a nuclear, ligand-dependent transcription factor that controls T3-responsive gene programs governing growth, differentiation, and metabolism [#0, #14, #15]. Its hormone-binding domain occupies the carboxy-terminal half of the protein, positionally analogous to that of steroid receptors [#2], and TRα1 functions as a bona fide T3 receptor that restores hormone-responsive induction of endogenous genes (growth hormone, prolactin, malic enzyme, PEPCK, Na+/K+-ATPase) in receptor-deficient cells [#15, #16]. A conserved 9-residue amphipathic helix at the extreme C-terminus (AF-2) is essential for T3-dependent transactivation, AP-1 interference, and erythroid differentiation, independently of T3 binding itself [#6, #17]. TRα1 efficiently activates transcription only as part of an RXR heterodimer, with the unique C-terminus conferring heterodimerization competence on TREs [#21], and unliganded receptor can repress competing pathways by sequestering RXR and dissociating RAR/RXR complexes [#8]; repression operates through corepressor and HDAC3 recruitment to chromatin [#19]. TRα1 acts as a ligand-controlled developmental switch: in the unliganded state it blocks NGF-induced neuronal differentiation, with T3 relieving the block [#22]. Receptor output is tuned at multiple layers from the same locus: alternative splicing produces TRα2, which cannot bind T3 and antagonizes TRα1/TRβ in dominant-negative fashion [#0]; an internal intron-7 promoter yields N-terminally truncated TRΔα isoforms that further attenuate TRα1 activity [#24]; the antisense Rev-ErbA alpha RNA shifts the α1/α2 ratio by inhibiting α2 splicing [#20]; and TRα1 is phosphorylated at N-terminal Ser12 by casein kinase II and at Ser28/29 by PKA/PKC [#3, #4]. Germline truncating and missense THRA mutations cause resistance to thyroid hormone alpha (RTHα), a syndrome of low fT4/fT3 ratio, macrocephaly, and skeletal dysplasia, acting through reduced T3 binding and dominant-negative interference [#26, #27]. Much of the early mechanistic dissection was performed through the constitutively repressive viral homolog v-ErbA, which lacks the AF-2 helix and functions as a dominant-negative oncogene antagonizing cellular TRα [#1, #17].\",\n  \"teleology\": [\n    {\n      \"year\": 1988,\n      \"claim\": \"Before its function was defined, it was unknown whether the c-erbA alpha protein was itself a hormone receptor; locating the hormone-binding domain to the C-terminal half established it as a steroid/nuclear receptor-class molecule and pinpointed where ligand control resides.\",\n      \"evidence\": \"Chimeric v-erbA/c-erbA proteins and ligand-binding assays of in vitro translated deletion mutants\",\n      \"pmids\": [\"3359993\", \"2464752\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of T3 binding not resolved\", \"Did not address DNA target sequences or cofactor requirements\"]\n    },\n    {\n      \"year\": 1988,\n      \"claim\": \"It was unclear whether c-erbA proteins were functional T3 receptors in cells; complementation in receptor-deficient lines showed they confer hormone-dependent regulation of growth hormone/prolactin and other endogenous genes, confirming receptor identity and predominantly nuclear localization.\",\n      \"evidence\": \"Transient expression with chimeric GH/PRL reporters in receptor-deficient versus receptor-containing cell lines; antibody fractionation and in vitro translation\",\n      \"pmids\": [\"2903439\", \"3054510\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Target gene repertoire incompletely mapped\", \"Internal-initiation isoform functions not yet defined\"]\n    },\n    {\n      \"year\": 1989,\n      \"claim\": \"The question of how a single locus produces opposing activities was answered by showing alternative splicing yields TRα1 (T3-activating) and TRα2 (non-T3-binding, dominant-negative), establishing intragenic antagonism as a regulatory principle.\",\n      \"evidence\": \"Transient transfection of T3-responsive reporters with in vitro translation and ligand-binding assays across multiple labs\",\n      \"pmids\": [\"2537467\", \"2903438\", \"2554288\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of TRα2 dominant-negativity not yet localized to a domain\", \"Splicing control of the α1/α2 ratio unknown\"]\n    },\n    {\n      \"year\": 1989,\n      \"claim\": \"To understand how the cellular receptor is post-translationally regulated, N-terminal phosphorylation sites were defined: PKA/PKC-enhanced Ser28/29 and casein kinase II-targeted Ser12, identifying kinase inputs onto receptor function.\",\n      \"evidence\": \"In vivo metabolic labeling, tryptic phosphopeptide mapping, in vitro kinase assays with purified PKA and CK2, and Ser12→Ala mutagenesis\",\n      \"pmids\": [\"2903825\", \"2552374\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of each phosphosite on transactivation not fully quantified\", \"Upstream signals driving these modifications in vivo unknown\"]\n    },\n    {\n      \"year\": 1989,\n      \"claim\": \"The transforming v-ErbA homolog was shown to be a constitutive repressor that dominantly blocks T3-dependent activation, providing the key tool to dissect activating versus repressive receptor functions; a zinc-finger DNA-binding mutation (Gly73→Ser) was linked to its loss of activation.\",\n      \"evidence\": \"Co-transfection of v-erbA/c-erbA with T3 reporters and chimeric ER/TRα DNA-binding-domain constructs\",\n      \"pmids\": [\"2733791\", \"1972036\", \"1682217\", \"1975094\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Repression mechanism (cofactors) not yet identified\", \"Relative contributions of DNA-binding versus ligand-binding lesions unresolved\"]\n    },\n    {\n      \"year\": 1990,\n      \"claim\": \"Mapping the difference between activating cellular receptor and repressive virus showed a conserved C-terminal 9-residue amphipathic helix (AF-2) is essential for T3-dependent transactivation, AP-1 interference, and erythroid differentiation, independent of T3 binding.\",\n      \"evidence\": \"c-ErbA/v-ErbA chimeras, single/double/triple substitution mutagenesis, reporter and erythroid differentiation assays\",\n      \"pmids\": [\"8098843\", \"1972036\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of coactivators engaging AF-2 not defined\", \"Structural mechanism of the helix not resolved\"]\n    },\n    {\n      \"year\": 1991,\n      \"claim\": \"How TRα cross-talks with other signaling outputs was clarified by demonstrating ligand-activated TRα1 represses AP-1-driven collagenase transcription while v-ErbA fails to do so, linking receptor activity to control of cell growth.\",\n      \"evidence\": \"Co-transfection AP-1 reporter assays and retinoic-acid growth assays in chicken embryo fibroblasts\",\n      \"pmids\": [\"1682056\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular contact mediating AP-1 interference not mapped\", \"Physiological relevance in mammals not tested here\"]\n    },\n    {\n      \"year\": 1992,\n      \"claim\": \"The basis of differential isoform DNA binding was localized: the unique TRα1 C-terminus enables heterodimerization on TREs, whereas the unique TRα2 C-terminus is an inhibitory domain that reduces DNA binding.\",\n      \"evidence\": \"In vitro synthesis with EMSA and heterodimerization assays of TRα1, TRα2, deletion and chimeric mutants\",\n      \"pmids\": [\"1318505\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Heterodimer partner identity not fully specified here\", \"In vivo relevance of isoform DNA-binding differences untested\"]\n    },\n    {\n      \"year\": 1993,\n      \"claim\": \"Mechanisms of trans-dominant antagonism were resolved: unliganded TRα suppresses RAR signaling by competing for shared RXR partner and dissociating RAR/RXR–RARE complexes, while v-ErbA functions chiefly through RXR heterodimerization and hinge-region-dependent trans-repression.\",\n      \"evidence\": \"EMSA dissociation and competition assays, RXR co-transfection rescue, and dimerization-interface/hinge mutagenesis (Pro349→Ser; Pro→Arg)\",\n      \"pmids\": [\"8096810\", \"8093812\", \"7902566\", \"8105369\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Quantitative contribution of competition versus active repression in vivo unclear\", \"Endogenous gene targets of RXR sequestration not enumerated\"]\n    },\n    {\n      \"year\": 1993,\n      \"claim\": \"TRα1 was established as a ligand-controlled developmental switch: unliganded receptor blocks NGF-induced neuronal differentiation and chromaffin commitment, with T3 relieving the neuronal block.\",\n      \"evidence\": \"Retroviral expression of TRα1/v-erbA in PC12 cells with NGF and dexamethasone differentiation and neuronal gene-expression assays; trk mRNA analysis in N2a cells\",\n      \"pmids\": [\"8385673\", \"8134111\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct target genes mediating the differentiation switch not all defined\", \"In vivo developmental requirement not addressed in these systems\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"The corepressor logic underlying receptor-mediated silencing was advanced by showing the antisense locus product Rev-ErbA alpha binds N-CoR via two interaction domains, foreshadowing the corepressor machinery that TRα-class receptors deploy.\",\n      \"evidence\": \"Mammalian two-hybrid and co-transfection repression assays with dominant-negative N-CoR fragments\",\n      \"pmids\": [\"8948627\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct demonstration on TRα1 itself not provided in this finding\", \"Single-lab two-hybrid without structural validation\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"The chromatin-level repression mechanism was defined: v-ErbA recruits N-CoR and HDAC3 to repress, but unlike TRα requires mature chromatin and binds TFIIB poorly, dissecting why the viral protein silences less efficiently on partly assembled templates.\",\n      \"evidence\": \"Xenopus oocyte chromatin assembly assays, TSA treatment, Co-IP of N-CoR/HDAC3, and in vitro TFIIB binding\",\n      \"pmids\": [\"10921888\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Equivalent stepwise mechanism for endogenous mammalian TRα not directly shown\", \"Other corepressors/coactivators not surveyed\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Additional layers of locus-encoded receptor tuning were identified: an internal intron-7 promoter generates N-terminally truncated TRΔα isoforms that selectively antagonize TRα1, and antisense Rev-ErbA alpha RNA inhibits TRα2 splicing to shift the α1/α2 ratio.\",\n      \"evidence\": \"5′ RACE promoter identification with reporter co-transfection (TRΔα1) and in vitro splicing assays with strand-specific antisense RNA\",\n      \"pmids\": [\"9259319\", \"1657988\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological abundance and tissue distribution of TRΔα isoforms not quantified\", \"In vivo significance of antisense splicing regulation not established\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Genetic epistasis in mice answered whether TRα1 and TRβ functions overlap, showing that increased TRα1 expression substitutes for loss of TRβ in deafness and thyroid hyperactivity, and that TRα2 is dispensable for hearing.\",\n      \"evidence\": \"Thra(tm2) allele in Thrb-null background with auditory brainstem response and thyroid hormone measurements\",\n      \"pmids\": [\"11726557\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Tissues where TRα1 cannot substitute for TRβ not delineated here\", \"Molecular basis of functional redundancy not addressed\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"The human disease relevance was established: germline THRA truncating and missense mutations cause resistance to thyroid hormone alpha (RTHα) through reduced T3 binding and dominant-negative interference, with genotype-phenotype correlation.\",\n      \"evidence\": \"Whole exome and Sanger sequencing in multiple families with longitudinal clinical/biochemical assessment, plus in vitro T3-binding, reporter, and dominant-negative assays of the N359Y mutant\",\n      \"pmids\": [\"25670821\", \"26037512\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Tissue-specific mechanisms of skeletal and growth phenotypes not fully resolved\", \"Functional assays performed on limited mutation set\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the multiple regulatory layers (splicing, antisense RNA, internal promoter, phosphorylation, cofactor recruitment) are integrated to set tissue-specific TRα1 output in human physiology and RTHα remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No integrated in vivo model linking phosphorylation, isoform ratios, and cofactor recruitment\", \"Tissue-resolved target gene programs of TRα1 not comprehensively mapped\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [0, 10, 15, 16, 22]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [13, 21, 28]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [14, 28]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [0, 15, 16]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [22]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [17, 22]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [26, 27]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"RXRA\", \"NCOR1\", \"HDAC3\", \"TFIIB\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}