{"gene":"PHOX2A","run_date":"2026-06-10T06:43:35","timeline":{"discoveries":[{"year":1997,"finding":"Phox2a is required for development of the locus coeruleus, subset of sympathetic/parasympathetic ganglia, and VIIth/IXth/Xth cranial sensory ganglia; in sensory ganglia, Phox2a knockout abolishes transient dopamine-beta-hydroxylase expression in neuroblasts and dramatically reduces Ret expression, leading to massive apoptosis.","method":"Targeted gene knockout (Phox2a-/- mice), immunohistochemistry, in situ hybridization","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean KO mouse with multiple defined cellular phenotypes, replicated across multiple neuronal populations","pmids":["9115735"],"is_preprint":false},{"year":1997,"finding":"Phox2a positively cross-regulates Phox2b: loss of Phox2b expression is observed in cranial ganglia of Phox2a-deficient mice, indicating Phox2a is upstream of Phox2b at those sites.","method":"In situ hybridization in Phox2a knockout mice","journal":"Development","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean KO mouse, defined molecular phenotype, single lab with orthogonal readouts","pmids":["9374403"],"is_preprint":false},{"year":1997,"finding":"Phox2a (Arix) interacts synergistically with cAMP to activate transcription from the DBH promoter via the DB1 regulatory element; neither Arix nor cAMP alone is sufficient, but together they substantially activate DBH transcription in non-neuronal cells.","method":"Transient transfection reporter assay, cotransfection with PKA catalytic subunit, EMSA with antisera supershift","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — reporter assay with multiple constructs and EMSA, single lab but multiple orthogonal methods","pmids":["9341190"],"is_preprint":false},{"year":1998,"finding":"Phox2a binds the homeodomain-binding site in the DBH promoter domain IV in a noradrenergic cell-specific manner and robustly activates DBH promoter activity (>10-fold) in DBH-negative cell lines; Phox2a does not activate tyrosine hydroxylase transcription, demonstrating selectivity.","method":"Electrophoretic mobility shift assay (EMSA), transient transfection reporter assay, forced expression","journal":"Journal of neurochemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — DNA binding demonstrated by EMSA, functional readout by reporter assay, replicated with Phox2b in same study","pmids":["9798905"],"is_preprint":false},{"year":1998,"finding":"Phox2a contains at least two binding sites in the DBH upstream promoter (domain IV and domain II); domain II is a second Phox2a-binding site and is a noradrenergic-specific element; four tandem copies of domain II increase minimal DBH promoter activity 100-200 fold in DBH-positive cells.","method":"EMSA, competition and antibody supershift assays, Southwestern analysis, transient transfection of mutant reporter constructs","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — multiple orthogonal methods (EMSA, supershift, reporter), mutagenesis, single lab","pmids":["9763470"],"is_preprint":false},{"year":1998,"finding":"MASH1 is required upstream of Phox2a: Phox2a expression is abolished or massively reduced in Mash1-/- mutant embryos in noradrenergic brain centers and peripheral autonomic ganglia, and constitutive MASH1 expression in neural crest stem cells induces Phox2a expression.","method":"In situ hybridization/immunohistochemistry in Mash1 knockout mice; retroviral vector-mediated constitutive MASH1 expression in NCSCs","journal":"Development","confidence":"High","confidence_rationale":"Tier 2 / Strong — loss-of-function and gain-of-function in two independent studies (PMID 9435281, 9435282) with consistent conclusions","pmids":["9435281","9435282"],"is_preprint":false},{"year":1998,"finding":"Constitutive Phox2a expression induces c-RET expression but fails to induce pan-neuronal markers or neuronal morphology, indicating Phox2a specifies a subtype-specific (rather than pan-neuronal) component of autonomic neuronal identity.","method":"Retroviral constitutive expression in neural crest stem cells, immunostaining","journal":"Development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — gain-of-function with defined molecular readout, single lab","pmids":["9435282"],"is_preprint":false},{"year":1999,"finding":"In zebrafish, soulless/Phox2a is not only necessary but sufficient to induce ectopic Phox2b+, dopamine-beta-hydroxylase+, and tyrosine hydroxylase+ noradrenergic neurons; Phox2a expression in locus coeruleus progenitors depends on FGF8 from the mid/hindbrain boundary and BMP signaling.","method":"Zebrafish forward genetics (soulless mutation), ectopic Phox2a overexpression, antisense morpholino knockdown","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — loss-of-function (mutation) and gain-of-function (overexpression) in vertebrate model with defined molecular and cellular phenotypes","pmids":["10595509"],"is_preprint":false},{"year":2000,"finding":"Arix/Phox2a contains an N-terminal activation domain and a C-terminal repression domain; the N-terminal domain contains an amino acid motif similar to Brachyury and Pax9; the N-terminal domain interacts with CBP, and this interaction potentiates PKA-dependent DBH transcription; Arix forms DNA-independent multimers.","method":"Mammalian one-hybrid and two-hybrid assays, deletion analysis, site-directed mutagenesis of homeodomain binding sites","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — multiple domain-mapping and interaction assays with functional readouts, single lab with several orthogonal methods","pmids":["10644760"],"is_preprint":false},{"year":2000,"finding":"Arix/Phox2a and Phox2b (NBPhox) bind to three sites in the DBH proximal promoter, form DNA-independent multimers, exhibit cooperative binding to the DB1 element (containing two homeodomain recognition sites), and independently stimulate DBH transcription synergistically with PKA; the N-terminal segment is essential for transcriptional activity.","method":"In vitro DNA binding assays, transient transfection reporter assay, co-expression experiments","journal":"DNA and cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro binding and reporter assays, single lab, consistent with prior findings","pmids":["11034547"],"is_preprint":false},{"year":2001,"finding":"Phox2b binds directly to a homeodomain factor-binding site in the 5' regulatory region of the human Phox2a promoter and transactivates Phox2a expression, providing molecular evidence that Phox2b directly regulates Phox2a transcription.","method":"EMSA, cotransfection reporter assay, promoter deletion analysis","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — EMSA showing direct binding plus functional reporter assay, two orthogonal methods, single lab","pmids":["11549713"],"is_preprint":false},{"year":2001,"finding":"Homozygous mutations in PHOX2A/ARIX (two predicted splicing mutations and one missense in the brachyury-like domain) cause congenital fibrosis of the extraocular muscles type 2 (CFEOM2), confirming PHOX2A is required for nIII/nIV oculomotor and trochlear nucleus development in humans.","method":"Human genetics — mutation identification by sequencing in four CFEOM2 pedigrees","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — human disease mutations identified across four independent pedigrees, consistent with mouse/zebrafish loss-of-function phenotypes","pmids":["11600883"],"is_preprint":false},{"year":2002,"finding":"Phox2a directly transactivates the DBH promoter through interactions with four binding sites (PBD1–3) in the proximal promoter; PBD1 interacts with Phox2a monomers while PBD2 and PBD3 interact with Phox2a dimers; homeodomain point mutations abolish both DBH transactivation in vitro and noradrenergic neuron development in vivo (zebrafish).","method":"EMSA with homeodomain mutants, transient transfection reporter assay, antisense oligonucleotide injection in zebrafish","journal":"Journal of neurochemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — homeodomain mutagenesis with both in vitro (reporter, EMSA) and in vivo (zebrafish) validation, multiple orthogonal methods","pmids":["11948255"],"is_preprint":false},{"year":2002,"finding":"Arix/Phox2a is constitutively phosphorylated in vivo; PKA pathway activation decreases Phox2a phosphorylation (dephosphorylation) and coincides with increased Arix DNA-binding activity; phosphatase inhibitors reverse both dephosphorylation and transcriptional activation, demonstrating that dephosphorylation of Phox2a is required for PKA-mediated DBH transcription.","method":"In vivo phosphorylation assay, EMSA, reporter assay, pharmacological manipulation (forskolin, phosphatase inhibitors)","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — post-translational modification linked mechanistically to DNA binding and transcription by multiple methods, single lab","pmids":["11943777"],"is_preprint":false},{"year":2003,"finding":"HAND2/dHAND synergistically enhances Phox2a-driven DBH transcription without directly binding to E-box sequences; HAND2 interacts with CBP in the transcriptional complex; the synergistic activation requires Phox2a homeodomain binding sites and is blocked by E1A; dHAND and Arix directly interact by protein-protein interaction (coprecipitation).","method":"Transient transfection reporter assay, co-immunoprecipitation, E1A inhibition, mutagenesis of HD-binding sites","journal":"Developmental biology / The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — co-IP demonstrating direct interaction, reporter mutagenesis, multiple orthogonal methods in two independent studies","pmids":["14512028","14506227"],"is_preprint":false},{"year":2001,"finding":"Phox2b is capable of transactivating the human Phox2a promoter (but not Phox2a itself or MASH1), as shown by cotransfection assays in Phox2a-negative HeLa cells.","method":"Cotransfection reporter assay in HeLa cells","journal":"Journal of neurochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional reporter assay, consistent with EMSA evidence from PMID 11549713, single lab","pmids":["11752063"],"is_preprint":false},{"year":1999,"finding":"Forced expression of Phox2a does not activate the norepinephrine transporter (NET) promoter in NET-negative cell lines, in contrast to its strong activation of the DBH promoter, indicating that distinct molecular mechanisms control NET and DBH cell-specific expression.","method":"Transient transfection reporter assay (negative result, mechanistically informative)","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — well-controlled reporter assay, negative result with positive DBH control in same experiment","pmids":["10037744"],"is_preprint":false},{"year":2004,"finding":"Phox2a gene and the A6 (locus coeruleus) noradrenergic neurons it generates are required for normal prenatal maturation of respiratory rhythm; noradrenaline released from A6 neurons potentiates rhythmic respiratory activity via alpha1 medullary adrenoceptors; transynaptic tracing confirmed A6 neurons are connected to the neonatal respiratory network.","method":"Phox2a knockout mouse respiratory measurements (in vivo ventilation, in vitro respiratory activity), pharmacological blockade (prazosin), rabies virus transynaptic tracing","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — KO mouse with multiple physiological readouts, pharmacological rescue, transynaptic tracing as orthogonal method","pmids":["14749437"],"is_preprint":false},{"year":2005,"finding":"cAMP-dependent PKA pathway activates Phox2a by promoting its dephosphorylation (at serine residues), which is required for Phox2a DNA binding and DBH-luciferase reporter expression; inhibition of PKA (H89) or PP2A-like phosphatase (okadaic acid) suppresses Phox2a dephosphorylation, DNA binding, and sympathoadrenal lineage development.","method":"Primary neural crest cultures, pharmacological inhibitors, in vitro DNA binding assay, reporter assay, dominant-negative CREB","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — mechanistic dissection with multiple pharmacological tools plus in vitro binding assay and reporter assay, single lab","pmids":["16204240"],"is_preprint":false},{"year":2006,"finding":"Phox2a induces p27Kip1 transcription by binding homeodomain cis-acting elements in the p27Kip1 promoter in vivo (chromatin immunoprecipitation) and mediates p27Kip1-luciferase expression; siRNA silencing of Phox2a suppresses p27Kip1 transcription and neuronal differentiation; this activity requires cAMP signaling.","method":"siRNA knockdown, tet-off ectopic expression, chromatin immunoprecipitation, luciferase reporter assay in CAD cells and primary NC cells","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — ChIP showing in vivo binding, loss-of-function and gain-of-function with reporter assay, multiple orthogonal methods in same study","pmids":["16982676"],"is_preprint":false},{"year":2007,"finding":"PHOX2A regulates the human alpha3 nicotinic acetylcholine receptor subunit gene promoter; PHOX2A assembles on the SacI-NcoI region of the alpha3 promoter (chromatin IP and DNA pulldown); it does not appear to bind DNA directly but interacts with Sp1 by co-immunoprecipitation, regulating alpha3 transcription through a DNA-independent protein-protein interaction mechanism.","method":"Chromatin immunoprecipitation, DNA pulldown, co-immunoprecipitation, cotransfection reporter assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — ChIP, pulldown, and co-IP with functional reporter validation, multiple orthogonal methods, single lab","pmids":["17344216"],"is_preprint":false},{"year":2009,"finding":"Phox2a is phosphorylated at a cluster of Ser-Pro sites identified by mass spectrometry; cAMP-dependent activation of Phox2a involves two sequential events: first, dephosphorylation of Ser206 enables DNA binding and p27Kip1 transcription initiation; second, PKA-dependent phosphorylation of Ser153 (after a delay) prevents DNA binding and terminates p27Kip1 transcription.","method":"Mass spectrometry phosphorylation site identification, phospho-specific antibody, Ser-to-Ala/Asp mutagenesis, inducible CAD cell lines, in vitro DNA binding assay","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — mass spectrometry identification of sites, site-directed mutagenesis, phospho-specific antibody, in vitro binding assay; multiple orthogonal methods in single study","pmids":["19564421"],"is_preprint":false},{"year":2005,"finding":"ERK1/2 phosphorylates Arix/Phox2a at two sites within the N-terminal transactivation domain; MEK1 inhibition reduces Phox2a phosphorylation in SH-SY5Y cells and increases interaction of Arix with DBH and NET (but not TH) gene targets and elevates DBH and NET mRNAs in sympathetic neurons, indicating ERK1/2-mediated phosphorylation negatively regulates Phox2a transcriptional activity.","method":"In vitro kinase assay (implied), MEK1 inhibitors (UO126, PD98059), chromatin association assay, qRT-PCR","journal":"Journal of neurochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological inhibition with chromatin association and mRNA readouts, phosphorylation site mapped; single lab","pmids":["16156742"],"is_preprint":false},{"year":2007,"finding":"PHOX2A directly regulates TLX2 transactivation: PHOX2A binds the TLX2 promoter (EMSA and chromatin immunoprecipitation) and transactivates it in cotransfection assays, establishing PHOX2A as part of the cascade leading to TLX2 expression in intestinal neuronal differentiation.","method":"Co-transfection reporter assay, EMSA, chromatin immunoprecipitation","journal":"European journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — ChIP plus EMSA plus reporter assay, multiple orthogonal methods; single lab","pmids":["17505528"],"is_preprint":false},{"year":2010,"finding":"Forced expression of PHOX2A in embryonic chick midbrain drives the complete oculomotor complex (OMC) molecular program, producing both visceral and somatic motoneurons and generating ectopic motor nerves that directly innervate extraocular muscle; PHOX2A both specifies motoneuron cell fate and orchestrates spatial organization of the nuclear complex.","method":"In ovo electroporation-mediated forced expression in chick midbrain, immunohistochemistry, axon tracing","journal":"Development","confidence":"High","confidence_rationale":"Tier 2 / Moderate — gain-of-function with multiple defined cellular and anatomical phenotypic readouts, including ectopic innervation; single lab","pmids":["20215354"],"is_preprint":false},{"year":2011,"finding":"Lmx1b regulates Phox2a expression in the ventral midbrain; loss of Lmx1b leads to disrupted Phox2a expression and impaired sequential specification of ocular motor neurons and red nucleus neurons from lateral progenitors.","method":"Lmx1b conditional knockout mouse, immunohistochemistry, in situ hybridization","journal":"Development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean conditional KO mouse, defined molecular phenotype; single lab","pmids":["21752929"],"is_preprint":false},{"year":2004,"finding":"Ciliary neurotrophic factor (CNTF) suppresses Phox2a expression in neuroblastoma cells and cultured sympathetic neurons, and Phox2a is absent in rat cholinergic sympathetic neurons (where noradrenergic enzymes are reduced), suggesting that CNTF-mediated suppression of TH and DBH occurs at least in part through reduction of Phox2a.","method":"Immunohistochemistry of sympathetic ganglia, western blot/RT-PCR in neuroblastoma cells and sympathetic neuron cultures","journal":"Neuroreport","confidence":"Low","confidence_rationale":"Tier 3 / Weak — correlation of Phox2a suppression with CNTF treatment; no direct causal experiment; single lab, single method approach","pmids":["15106827"],"is_preprint":false},{"year":2020,"finding":"Most mouse spinal neurons that embryonically express Phox2a innervate nociceptive brain targets (parabrachial nucleus and thalamus); Phox2a is required for the development of relay of nociceptive signals from spinal cord to brain, as loss of Phox2a leads to defects in anterolateral system neuron differentiation and nociceptive signaling.","method":"Phox2a::Cre fate mapping, retrograde tracing, Phox2a knockout analysis, immunohistochemistry in mouse and human fetal spinal cord","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Moderate — lineage tracing combined with retrograde tracing and loss-of-function with nociceptive circuit phenotype; multiple orthogonal methods","pmids":["33238113"],"is_preprint":false},{"year":2022,"finding":"DCC deletion in Phox2a neurons causes impaired topognosis along the rostrocaudal axis and defective somatotopic targeting of cervical and lumbar anterolateral system axons within the thalamus, placing DCC/netrin-1 signaling downstream of Phox2a neuronal identity in the formation of somatotopically ordered nociceptive maps.","method":"Conditional Dcc knockout in Phox2a neurons, anatomical tracing, behavioral assays (topognosis)","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional KO with anatomical and behavioral phenotypes; single lab","pmids":["36028316"],"is_preprint":false},{"year":2023,"finding":"Prdm12 is required to repress Phox2a/b expression in somatosensory neural precursors; loss of Prdm12 results in ectopic Phox2a and Phox2b expression in trigeminal and dorsal root ganglia, indicating Prdm12 acts upstream of Phox2a to prevent precursors from adopting a visceral neuronal fate.","method":"Prdm12 knockout mouse analysis, immunohistochemistry, in situ hybridization","journal":"iScience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with defined molecular phenotype; single lab","pmids":["38025786"],"is_preprint":false},{"year":2025,"finding":"Phox2a expressed in Tac1+ neurons of the lateral spinal nucleus (LSN) negatively regulates histamine-independent itch; Phox2a is downregulated during chloroquine-induced itch; overexpression of Phox2a in LSNTac1 neurons reduces scratching and decreases spontaneous excitatory postsynaptic current amplitude (without changing frequency), indicating a presynaptic mechanism.","method":"Chemogenetic manipulation (viral-mediated activation/inhibition), whole-cell patch-clamp recording, Western blotting, FISH, behavioral assays","journal":"CNS neuroscience & therapeutics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple methods (chemogenetics, electrophysiology, behavior) in single study; single lab","pmids":["41204431"],"is_preprint":false},{"year":2024,"finding":"A PHOX2A variant (p.Trp137Cys) in the homeodomain reduces or abolishes DNA binding as demonstrated by protein binding microarray, supporting that this residue is critical for PHOX2A transcription factor activity and that this variant is pathogenic in ocular congenital cranial dysinnervation disorder.","method":"Protein binding microarray, G0 CRISPR/Cas9 zebrafish knockout screen","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — protein binding microarray provides direct DNA-binding functional data; preprint, single study","pmids":[],"is_preprint":true}],"current_model":"PHOX2A is a paired-like homeodomain transcription factor that acts downstream of MASH1 and Phox2b/BMP/FGF8 signals to specify noradrenergic and autonomic neuronal identity; it directly binds multiple homeodomain sites in the DBH (and other target gene) promoters—as a monomer at PBD1 and dimer at PBD2/3—to activate transcription synergistically with cAMP/PKA signaling, a process regulated by sequential dephosphorylation (at Ser206, enabling DNA binding) and PKA-dependent rephosphorylation (at Ser153, terminating activity), as well as negative regulation by ERK1/2 phosphorylation; it also induces p27Kip1 to coordinate cell-cycle exit with neuronal differentiation, interacts with co-activators CBP and Sp1, and in the mature nervous system is required for oculomotor/trochlear nucleus development, locus coeruleus-dependent respiratory rhythm, and anterolateral system nociceptive circuit formation."},"narrative":{"mechanistic_narrative":"PHOX2A is a paired-like homeodomain transcription factor that specifies noradrenergic and autonomic neuronal identity during development [PMID:9115735, PMID:10595509]. It is positioned within a defined regulatory cascade: MASH1 acts upstream to drive Phox2a expression in noradrenergic centers and autonomic ganglia [PMID:9435281, PMID:9435282], and FGF8 and BMP signals from the mid/hindbrain boundary control its induction in locus coeruleus progenitors [PMID:10595509], while PHOX2B directly binds and transactivates the PHOX2A promoter [PMID:11549713]; Phox2a in turn cross-regulates Phox2b at cranial ganglia, making the two factors mutually dependent in distinct contexts [PMID:9374403]. Its principal transcriptional target is the dopamine-β-hydroxylase (DBH) gene, which it activates in a noradrenergic-specific manner by binding multiple homeodomain sites in the proximal promoter—engaging PBD1 as a monomer and PBD2/PBD3 as dimers—with target selectivity such that it activates DBH but not tyrosine hydroxylase [PMID:9798905, PMID:9763470, PMID:11948255]. Activation is synergistic with the cAMP/PKA pathway and is potentiated by the co-activator CBP, which binds the N-terminal activation domain, and by HAND2, which directly interacts with PHOX2A to enhance DBH transcription [PMID:9341190, PMID:10644760, PMID:14512028, PMID:14506227]. PHOX2A activity is gated by phosphorylation: constitutive phosphorylation is removed by PP2A-like dephosphorylation at Ser206 to enable DNA binding, followed after a delay by PKA-dependent rephosphorylation at Ser153 that terminates activity, while ERK1/2 phosphorylation in the N-terminal domain negatively regulates target engagement [PMID:11943777, PMID:16204240, PMID:19564421, PMID:16156742]. Beyond noradrenergic enzyme genes, PHOX2A induces the cell-cycle inhibitor p27Kip1 to couple cell-cycle exit to differentiation, transactivates TLX2, and regulates the α3 nicotinic receptor subunit gene through a DNA-independent interaction with Sp1 [PMID:16982676, PMID:17344216, PMID:17505528]. In the mature nervous system PHOX2A is required for oculomotor and trochlear nucleus development—homozygous PHOX2A mutations cause congenital fibrosis of the extraocular muscles type 2 (CFEOM2) [PMID:11600883, PMID:20215354]—for locus coeruleus-dependent respiratory rhythm maturation [PMID:14749437], and for formation of the anterolateral system nociceptive relay from spinal cord to brain [PMID:33238113, PMID:36028316].","teleology":[{"year":1997,"claim":"Established PHOX2A as an essential developmental regulator by showing its loss eliminates specific noradrenergic and autonomic neuronal populations and triggers apoptosis.","evidence":"Targeted Phox2a knockout mice with immunohistochemistry and in situ hybridization","pmids":["9115735","9374403"],"confidence":"High","gaps":["Did not establish direct transcriptional targets","Cross-regulation with Phox2b directionally context-dependent and not resolved mechanistically"]},{"year":1997,"claim":"Identified DBH as a direct functional target and revealed that PHOX2A requires cAMP synergy rather than acting alone.","evidence":"Reporter assays with PKA cotransfection and EMSA supershift in non-neuronal cells","pmids":["9341190"],"confidence":"High","gaps":["Did not map the phosphorylation events linking cAMP to PHOX2A activity","Mechanism of synergy not defined at the protein level"]},{"year":1998,"claim":"Defined the cell-specific DNA-binding architecture of PHOX2A on the DBH promoter and demonstrated target selectivity versus tyrosine hydroxylase.","evidence":"EMSA, Southwestern, supershift, and mutant reporter constructs in noradrenergic and DBH-negative cell lines","pmids":["9798905","9763470"],"confidence":"High","gaps":["Monomer vs dimer occupancy not yet resolved","Co-factors mediating selectivity unknown"]},{"year":1998,"claim":"Placed PHOX2A downstream of MASH1 and showed it specifies a subtype-specific, not pan-neuronal, identity program.","evidence":"Mash1 knockout in situ analysis and retroviral MASH1/Phox2a forced expression in neural crest stem cells","pmids":["9435281","9435282"],"confidence":"High","gaps":["Additional targets beyond c-RET not identified","Does not explain how pan-neuronal differentiation is supplied"]},{"year":1999,"claim":"Demonstrated PHOX2A is both necessary and sufficient for noradrenergic neuron formation in vivo and identified FGF8/BMP as upstream inducers.","evidence":"Zebrafish soulless mutant, ectopic overexpression, and morpholino knockdown","pmids":["10595509"],"confidence":"High","gaps":["Signaling link from FGF8/BMP to Phox2a transcription not mapped","Target gene readout limited to DBH/TH/Phox2b"]},{"year":2000,"claim":"Mapped PHOX2A functional domains and identified CBP as a co-activator potentiating PKA-dependent transcription, plus DNA-independent multimerization.","evidence":"One- and two-hybrid assays, deletion analysis, and homeodomain-site mutagenesis","pmids":["10644760","11034547"],"confidence":"High","gaps":["Stoichiometry and functional role of multimers in vivo unclear","How N-terminal domain engages the transcription machinery not defined"]},{"year":2001,"claim":"Established the regulatory loop with PHOX2B by showing PHOX2B directly binds and transactivates the PHOX2A promoter.","evidence":"EMSA, promoter deletion, and cotransfection reporter assays","pmids":["11549713","11752063"],"confidence":"High","gaps":["In vivo significance of direct binding versus genetic cross-regulation not separated","Tissue specificity of the interaction not resolved"]},{"year":2001,"claim":"Linked PHOX2A directly to human disease, demonstrating it is required for oculomotor and trochlear nucleus development.","evidence":"Mutation identification in four CFEOM2 pedigrees","pmids":["11600883"],"confidence":"High","gaps":["Functional consequences of individual mutations not biochemically tested at the time","Target genes in oculomotor lineage not defined"]},{"year":2002,"claim":"Resolved the binding mode on DBH (monomer at PBD1, dimers at PBD2/3) and tied homeodomain function to in vivo neuron development.","evidence":"EMSA with homeodomain mutants, reporter assays, and antisense injection in zebrafish","pmids":["11948255"],"confidence":"High","gaps":["Determinants of monomer vs dimer site selection not identified","Broader target set not surveyed"]},{"year":2002,"claim":"Showed that dephosphorylation is the switch coupling PKA signaling to PHOX2A DNA binding and transcription.","evidence":"In vivo phosphorylation assay, EMSA, reporter assays, and phosphatase inhibitor manipulation","pmids":["11943777"],"confidence":"High","gaps":["Specific residues not yet identified","Phosphatase identity inferred but not purified"]},{"year":2003,"claim":"Identified HAND2 as a direct protein partner that enhances PHOX2A-driven DBH transcription via CBP.","evidence":"Reporter assays, co-immunoprecipitation, E1A inhibition, and HD-site mutagenesis","pmids":["14512028","14506227"],"confidence":"High","gaps":["Structural basis of the HAND2-PHOX2A interaction unknown","In vivo requirement of the interaction not tested"]},{"year":2005,"claim":"Demonstrated PKA/PP2A-driven dephosphorylation controls PHOX2A activity and sympathoadrenal lineage development, and that ERK1/2 phosphorylation negatively regulates it.","evidence":"Primary neural crest cultures, pharmacological inhibitors, in vitro binding, reporter assays, and chromatin association/qRT-PCR in SH-SY5Y","pmids":["16204240","16156742"],"confidence":"High","gaps":["ERK1/2 site mapping correlational in cells","Integration of opposing kinase/phosphatase inputs not modeled"]},{"year":2006,"claim":"Connected PHOX2A to cell-cycle exit by showing it directly induces p27Kip1 to coordinate proliferation arrest with differentiation.","evidence":"siRNA knockdown, tet-off expression, ChIP, and luciferase reporter assays in CAD and primary neural crest cells","pmids":["16982676"],"confidence":"High","gaps":["Quantitative contribution of p27Kip1 to the differentiation phenotype unclear","cAMP dependence mechanism not fully resolved"]},{"year":2007,"claim":"Broadened the target repertoire by establishing direct transactivation of TLX2 and a DNA-independent, Sp1-mediated mechanism at the α3 nicotinic receptor promoter.","evidence":"EMSA, ChIP, DNA pulldown, co-immunoprecipitation, and reporter assays","pmids":["17344216","17505528"],"confidence":"High","gaps":["Generality of the DNA-independent Sp1 mechanism to other targets unknown","In vivo relevance of TLX2 regulation not tested"]},{"year":2009,"claim":"Defined a two-step phosphorylation timer that initiates and then terminates PHOX2A activity at single-residue resolution.","evidence":"Mass spectrometry, phospho-specific antibody, Ser-to-Ala/Asp mutagenesis, inducible CAD cells, and in vitro binding assays","pmids":["19564421"],"confidence":"High","gaps":["Kinase responsible for delayed Ser153 phosphorylation not purified","How timing delay is set mechanistically unknown"]},{"year":2010,"claim":"Showed PHOX2A is sufficient to drive the complete oculomotor complex program and organize the nuclear/axonal architecture.","evidence":"In ovo electroporation forced expression in chick midbrain, immunohistochemistry, axon tracing","pmids":["20215354"],"confidence":"High","gaps":["Downstream effectors of spatial organization not identified","Direct target genes in motoneuron program not enumerated"]},{"year":2011,"claim":"Identified Lmx1b as an upstream regulator of Phox2a in the ventral midbrain ocular motor lineage.","evidence":"Lmx1b conditional knockout, immunohistochemistry, in situ hybridization","pmids":["21752929"],"confidence":"Medium","gaps":["Direct vs indirect regulation by Lmx1b not distinguished","Single lab"]},{"year":2020,"claim":"Revealed a new circuit role: PHOX2A is required for development of the anterolateral system relaying nociceptive signals from spinal cord to brain.","evidence":"Phox2a::Cre fate mapping, retrograde tracing, knockout analysis in mouse and human fetal spinal cord","pmids":["33238113"],"confidence":"High","gaps":["Direct transcriptional targets in this lineage unknown","Molecular link to axon targeting not defined here"]},{"year":2022,"claim":"Placed DCC/netrin-1 signaling downstream of PHOX2A identity in building somatotopic nociceptive maps.","evidence":"Conditional Dcc knockout in Phox2a neurons, anatomical tracing, topognosis behavior","pmids":["36028316"],"confidence":"Medium","gaps":["Whether PHOX2A directly regulates DCC not tested","Single lab"]},{"year":2025,"claim":"Extended PHOX2A function to modulation of itch by showing it presynaptically suppresses histamine-independent itch in lateral spinal nucleus Tac1+ neurons.","evidence":"Chemogenetics, whole-cell patch-clamp, Western blot, FISH, and behavioral assays","pmids":["41204431"],"confidence":"Medium","gaps":["Transcriptional targets mediating the presynaptic effect unknown","Single lab"]},{"year":null,"claim":"How upstream 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apoptosis.\",\n      \"method\": \"Targeted gene knockout (Phox2a-/- mice), immunohistochemistry, in situ hybridization\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean KO mouse with multiple defined cellular phenotypes, replicated across multiple neuronal populations\",\n      \"pmids\": [\"9115735\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Phox2a positively cross-regulates Phox2b: loss of Phox2b expression is observed in cranial ganglia of Phox2a-deficient mice, indicating Phox2a is upstream of Phox2b at those sites.\",\n      \"method\": \"In situ hybridization in Phox2a knockout mice\",\n      \"journal\": \"Development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO mouse, defined molecular phenotype, single lab with orthogonal readouts\",\n      \"pmids\": [\"9374403\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Phox2a (Arix) interacts synergistically with cAMP to activate transcription from the DBH promoter via the DB1 regulatory element; neither Arix nor cAMP alone is sufficient, but together they substantially activate DBH transcription in non-neuronal cells.\",\n      \"method\": \"Transient transfection reporter assay, cotransfection with PKA catalytic subunit, EMSA with antisera supershift\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — reporter assay with multiple constructs and EMSA, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"9341190\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Phox2a binds the homeodomain-binding site in the DBH promoter domain IV in a noradrenergic cell-specific manner and robustly activates DBH promoter activity (>10-fold) in DBH-negative cell lines; Phox2a does not activate tyrosine hydroxylase transcription, demonstrating selectivity.\",\n      \"method\": \"Electrophoretic mobility shift assay (EMSA), transient transfection reporter assay, forced expression\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — DNA binding demonstrated by EMSA, functional readout by reporter assay, replicated with Phox2b in same study\",\n      \"pmids\": [\"9798905\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Phox2a contains at least two binding sites in the DBH upstream promoter (domain IV and domain II); domain II is a second Phox2a-binding site and is a noradrenergic-specific element; four tandem copies of domain II increase minimal DBH promoter activity 100-200 fold in DBH-positive cells.\",\n      \"method\": \"EMSA, competition and antibody supershift assays, Southwestern analysis, transient transfection of mutant reporter constructs\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — multiple orthogonal methods (EMSA, supershift, reporter), mutagenesis, single lab\",\n      \"pmids\": [\"9763470\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"MASH1 is required upstream of Phox2a: Phox2a expression is abolished or massively reduced in Mash1-/- mutant embryos in noradrenergic brain centers and peripheral autonomic ganglia, and constitutive MASH1 expression in neural crest stem cells induces Phox2a expression.\",\n      \"method\": \"In situ hybridization/immunohistochemistry in Mash1 knockout mice; retroviral vector-mediated constitutive MASH1 expression in NCSCs\",\n      \"journal\": \"Development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — loss-of-function and gain-of-function in two independent studies (PMID 9435281, 9435282) with consistent conclusions\",\n      \"pmids\": [\"9435281\", \"9435282\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Constitutive Phox2a expression induces c-RET expression but fails to induce pan-neuronal markers or neuronal morphology, indicating Phox2a specifies a subtype-specific (rather than pan-neuronal) component of autonomic neuronal identity.\",\n      \"method\": \"Retroviral constitutive expression in neural crest stem cells, immunostaining\",\n      \"journal\": \"Development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — gain-of-function with defined molecular readout, single lab\",\n      \"pmids\": [\"9435282\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"In zebrafish, soulless/Phox2a is not only necessary but sufficient to induce ectopic Phox2b+, dopamine-beta-hydroxylase+, and tyrosine hydroxylase+ noradrenergic neurons; Phox2a expression in locus coeruleus progenitors depends on FGF8 from the mid/hindbrain boundary and BMP signaling.\",\n      \"method\": \"Zebrafish forward genetics (soulless mutation), ectopic Phox2a overexpression, antisense morpholino knockdown\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — loss-of-function (mutation) and gain-of-function (overexpression) in vertebrate model with defined molecular and cellular phenotypes\",\n      \"pmids\": [\"10595509\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Arix/Phox2a contains an N-terminal activation domain and a C-terminal repression domain; the N-terminal domain contains an amino acid motif similar to Brachyury and Pax9; the N-terminal domain interacts with CBP, and this interaction potentiates PKA-dependent DBH transcription; Arix forms DNA-independent multimers.\",\n      \"method\": \"Mammalian one-hybrid and two-hybrid assays, deletion analysis, site-directed mutagenesis of homeodomain binding sites\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — multiple domain-mapping and interaction assays with functional readouts, single lab with several orthogonal methods\",\n      \"pmids\": [\"10644760\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Arix/Phox2a and Phox2b (NBPhox) bind to three sites in the DBH proximal promoter, form DNA-independent multimers, exhibit cooperative binding to the DB1 element (containing two homeodomain recognition sites), and independently stimulate DBH transcription synergistically with PKA; the N-terminal segment is essential for transcriptional activity.\",\n      \"method\": \"In vitro DNA binding assays, transient transfection reporter assay, co-expression experiments\",\n      \"journal\": \"DNA and cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro binding and reporter assays, single lab, consistent with prior findings\",\n      \"pmids\": [\"11034547\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Phox2b binds directly to a homeodomain factor-binding site in the 5' regulatory region of the human Phox2a promoter and transactivates Phox2a expression, providing molecular evidence that Phox2b directly regulates Phox2a transcription.\",\n      \"method\": \"EMSA, cotransfection reporter assay, promoter deletion analysis\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — EMSA showing direct binding plus functional reporter assay, two orthogonal methods, single lab\",\n      \"pmids\": [\"11549713\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Homozygous mutations in PHOX2A/ARIX (two predicted splicing mutations and one missense in the brachyury-like domain) cause congenital fibrosis of the extraocular muscles type 2 (CFEOM2), confirming PHOX2A is required for nIII/nIV oculomotor and trochlear nucleus development in humans.\",\n      \"method\": \"Human genetics — mutation identification by sequencing in four CFEOM2 pedigrees\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — human disease mutations identified across four independent pedigrees, consistent with mouse/zebrafish loss-of-function phenotypes\",\n      \"pmids\": [\"11600883\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Phox2a directly transactivates the DBH promoter through interactions with four binding sites (PBD1–3) in the proximal promoter; PBD1 interacts with Phox2a monomers while PBD2 and PBD3 interact with Phox2a dimers; homeodomain point mutations abolish both DBH transactivation in vitro and noradrenergic neuron development in vivo (zebrafish).\",\n      \"method\": \"EMSA with homeodomain mutants, transient transfection reporter assay, antisense oligonucleotide injection in zebrafish\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — homeodomain mutagenesis with both in vitro (reporter, EMSA) and in vivo (zebrafish) validation, multiple orthogonal methods\",\n      \"pmids\": [\"11948255\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Arix/Phox2a is constitutively phosphorylated in vivo; PKA pathway activation decreases Phox2a phosphorylation (dephosphorylation) and coincides with increased Arix DNA-binding activity; phosphatase inhibitors reverse both dephosphorylation and transcriptional activation, demonstrating that dephosphorylation of Phox2a is required for PKA-mediated DBH transcription.\",\n      \"method\": \"In vivo phosphorylation assay, EMSA, reporter assay, pharmacological manipulation (forskolin, phosphatase inhibitors)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — post-translational modification linked mechanistically to DNA binding and transcription by multiple methods, single lab\",\n      \"pmids\": [\"11943777\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"HAND2/dHAND synergistically enhances Phox2a-driven DBH transcription without directly binding to E-box sequences; HAND2 interacts with CBP in the transcriptional complex; the synergistic activation requires Phox2a homeodomain binding sites and is blocked by E1A; dHAND and Arix directly interact by protein-protein interaction (coprecipitation).\",\n      \"method\": \"Transient transfection reporter assay, co-immunoprecipitation, E1A inhibition, mutagenesis of HD-binding sites\",\n      \"journal\": \"Developmental biology / The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP demonstrating direct interaction, reporter mutagenesis, multiple orthogonal methods in two independent studies\",\n      \"pmids\": [\"14512028\", \"14506227\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Phox2b is capable of transactivating the human Phox2a promoter (but not Phox2a itself or MASH1), as shown by cotransfection assays in Phox2a-negative HeLa cells.\",\n      \"method\": \"Cotransfection reporter assay in HeLa cells\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional reporter assay, consistent with EMSA evidence from PMID 11549713, single lab\",\n      \"pmids\": [\"11752063\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Forced expression of Phox2a does not activate the norepinephrine transporter (NET) promoter in NET-negative cell lines, in contrast to its strong activation of the DBH promoter, indicating that distinct molecular mechanisms control NET and DBH cell-specific expression.\",\n      \"method\": \"Transient transfection reporter assay (negative result, mechanistically informative)\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — well-controlled reporter assay, negative result with positive DBH control in same experiment\",\n      \"pmids\": [\"10037744\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Phox2a gene and the A6 (locus coeruleus) noradrenergic neurons it generates are required for normal prenatal maturation of respiratory rhythm; noradrenaline released from A6 neurons potentiates rhythmic respiratory activity via alpha1 medullary adrenoceptors; transynaptic tracing confirmed A6 neurons are connected to the neonatal respiratory network.\",\n      \"method\": \"Phox2a knockout mouse respiratory measurements (in vivo ventilation, in vitro respiratory activity), pharmacological blockade (prazosin), rabies virus transynaptic tracing\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — KO mouse with multiple physiological readouts, pharmacological rescue, transynaptic tracing as orthogonal method\",\n      \"pmids\": [\"14749437\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"cAMP-dependent PKA pathway activates Phox2a by promoting its dephosphorylation (at serine residues), which is required for Phox2a DNA binding and DBH-luciferase reporter expression; inhibition of PKA (H89) or PP2A-like phosphatase (okadaic acid) suppresses Phox2a dephosphorylation, DNA binding, and sympathoadrenal lineage development.\",\n      \"method\": \"Primary neural crest cultures, pharmacological inhibitors, in vitro DNA binding assay, reporter assay, dominant-negative CREB\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — mechanistic dissection with multiple pharmacological tools plus in vitro binding assay and reporter assay, single lab\",\n      \"pmids\": [\"16204240\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Phox2a induces p27Kip1 transcription by binding homeodomain cis-acting elements in the p27Kip1 promoter in vivo (chromatin immunoprecipitation) and mediates p27Kip1-luciferase expression; siRNA silencing of Phox2a suppresses p27Kip1 transcription and neuronal differentiation; this activity requires cAMP signaling.\",\n      \"method\": \"siRNA knockdown, tet-off ectopic expression, chromatin immunoprecipitation, luciferase reporter assay in CAD cells and primary NC cells\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — ChIP showing in vivo binding, loss-of-function and gain-of-function with reporter assay, multiple orthogonal methods in same study\",\n      \"pmids\": [\"16982676\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"PHOX2A regulates the human alpha3 nicotinic acetylcholine receptor subunit gene promoter; PHOX2A assembles on the SacI-NcoI region of the alpha3 promoter (chromatin IP and DNA pulldown); it does not appear to bind DNA directly but interacts with Sp1 by co-immunoprecipitation, regulating alpha3 transcription through a DNA-independent protein-protein interaction mechanism.\",\n      \"method\": \"Chromatin immunoprecipitation, DNA pulldown, co-immunoprecipitation, cotransfection reporter assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — ChIP, pulldown, and co-IP with functional reporter validation, multiple orthogonal methods, single lab\",\n      \"pmids\": [\"17344216\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Phox2a is phosphorylated at a cluster of Ser-Pro sites identified by mass spectrometry; cAMP-dependent activation of Phox2a involves two sequential events: first, dephosphorylation of Ser206 enables DNA binding and p27Kip1 transcription initiation; second, PKA-dependent phosphorylation of Ser153 (after a delay) prevents DNA binding and terminates p27Kip1 transcription.\",\n      \"method\": \"Mass spectrometry phosphorylation site identification, phospho-specific antibody, Ser-to-Ala/Asp mutagenesis, inducible CAD cell lines, in vitro DNA binding assay\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mass spectrometry identification of sites, site-directed mutagenesis, phospho-specific antibody, in vitro binding assay; multiple orthogonal methods in single study\",\n      \"pmids\": [\"19564421\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"ERK1/2 phosphorylates Arix/Phox2a at two sites within the N-terminal transactivation domain; MEK1 inhibition reduces Phox2a phosphorylation in SH-SY5Y cells and increases interaction of Arix with DBH and NET (but not TH) gene targets and elevates DBH and NET mRNAs in sympathetic neurons, indicating ERK1/2-mediated phosphorylation negatively regulates Phox2a transcriptional activity.\",\n      \"method\": \"In vitro kinase assay (implied), MEK1 inhibitors (UO126, PD98059), chromatin association assay, qRT-PCR\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological inhibition with chromatin association and mRNA readouts, phosphorylation site mapped; single lab\",\n      \"pmids\": [\"16156742\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"PHOX2A directly regulates TLX2 transactivation: PHOX2A binds the TLX2 promoter (EMSA and chromatin immunoprecipitation) and transactivates it in cotransfection assays, establishing PHOX2A as part of the cascade leading to TLX2 expression in intestinal neuronal differentiation.\",\n      \"method\": \"Co-transfection reporter assay, EMSA, chromatin immunoprecipitation\",\n      \"journal\": \"European journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — ChIP plus EMSA plus reporter assay, multiple orthogonal methods; single lab\",\n      \"pmids\": [\"17505528\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Forced expression of PHOX2A in embryonic chick midbrain drives the complete oculomotor complex (OMC) molecular program, producing both visceral and somatic motoneurons and generating ectopic motor nerves that directly innervate extraocular muscle; PHOX2A both specifies motoneuron cell fate and orchestrates spatial organization of the nuclear complex.\",\n      \"method\": \"In ovo electroporation-mediated forced expression in chick midbrain, immunohistochemistry, axon tracing\",\n      \"journal\": \"Development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — gain-of-function with multiple defined cellular and anatomical phenotypic readouts, including ectopic innervation; single lab\",\n      \"pmids\": [\"20215354\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Lmx1b regulates Phox2a expression in the ventral midbrain; loss of Lmx1b leads to disrupted Phox2a expression and impaired sequential specification of ocular motor neurons and red nucleus neurons from lateral progenitors.\",\n      \"method\": \"Lmx1b conditional knockout mouse, immunohistochemistry, in situ hybridization\",\n      \"journal\": \"Development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean conditional KO mouse, defined molecular phenotype; single lab\",\n      \"pmids\": [\"21752929\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Ciliary neurotrophic factor (CNTF) suppresses Phox2a expression in neuroblastoma cells and cultured sympathetic neurons, and Phox2a is absent in rat cholinergic sympathetic neurons (where noradrenergic enzymes are reduced), suggesting that CNTF-mediated suppression of TH and DBH occurs at least in part through reduction of Phox2a.\",\n      \"method\": \"Immunohistochemistry of sympathetic ganglia, western blot/RT-PCR in neuroblastoma cells and sympathetic neuron cultures\",\n      \"journal\": \"Neuroreport\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — correlation of Phox2a suppression with CNTF treatment; no direct causal experiment; single lab, single method approach\",\n      \"pmids\": [\"15106827\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Most mouse spinal neurons that embryonically express Phox2a innervate nociceptive brain targets (parabrachial nucleus and thalamus); Phox2a is required for the development of relay of nociceptive signals from spinal cord to brain, as loss of Phox2a leads to defects in anterolateral system neuron differentiation and nociceptive signaling.\",\n      \"method\": \"Phox2a::Cre fate mapping, retrograde tracing, Phox2a knockout analysis, immunohistochemistry in mouse and human fetal spinal cord\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — lineage tracing combined with retrograde tracing and loss-of-function with nociceptive circuit phenotype; multiple orthogonal methods\",\n      \"pmids\": [\"33238113\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"DCC deletion in Phox2a neurons causes impaired topognosis along the rostrocaudal axis and defective somatotopic targeting of cervical and lumbar anterolateral system axons within the thalamus, placing DCC/netrin-1 signaling downstream of Phox2a neuronal identity in the formation of somatotopically ordered nociceptive maps.\",\n      \"method\": \"Conditional Dcc knockout in Phox2a neurons, anatomical tracing, behavioral assays (topognosis)\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional KO with anatomical and behavioral phenotypes; single lab\",\n      \"pmids\": [\"36028316\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Prdm12 is required to repress Phox2a/b expression in somatosensory neural precursors; loss of Prdm12 results in ectopic Phox2a and Phox2b expression in trigeminal and dorsal root ganglia, indicating Prdm12 acts upstream of Phox2a to prevent precursors from adopting a visceral neuronal fate.\",\n      \"method\": \"Prdm12 knockout mouse analysis, immunohistochemistry, in situ hybridization\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with defined molecular phenotype; single lab\",\n      \"pmids\": [\"38025786\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Phox2a expressed in Tac1+ neurons of the lateral spinal nucleus (LSN) negatively regulates histamine-independent itch; Phox2a is downregulated during chloroquine-induced itch; overexpression of Phox2a in LSNTac1 neurons reduces scratching and decreases spontaneous excitatory postsynaptic current amplitude (without changing frequency), indicating a presynaptic mechanism.\",\n      \"method\": \"Chemogenetic manipulation (viral-mediated activation/inhibition), whole-cell patch-clamp recording, Western blotting, FISH, behavioral assays\",\n      \"journal\": \"CNS neuroscience & therapeutics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple methods (chemogenetics, electrophysiology, behavior) in single study; single lab\",\n      \"pmids\": [\"41204431\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"A PHOX2A variant (p.Trp137Cys) in the homeodomain reduces or abolishes DNA binding as demonstrated by protein binding microarray, supporting that this residue is critical for PHOX2A transcription factor activity and that this variant is pathogenic in ocular congenital cranial dysinnervation disorder.\",\n      \"method\": \"Protein binding microarray, G0 CRISPR/Cas9 zebrafish knockout screen\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — protein binding microarray provides direct DNA-binding functional data; preprint, single study\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"PHOX2A is a paired-like homeodomain transcription factor that acts downstream of MASH1 and Phox2b/BMP/FGF8 signals to specify noradrenergic and autonomic neuronal identity; it directly binds multiple homeodomain sites in the DBH (and other target gene) promoters—as a monomer at PBD1 and dimer at PBD2/3—to activate transcription synergistically with cAMP/PKA signaling, a process regulated by sequential dephosphorylation (at Ser206, enabling DNA binding) and PKA-dependent rephosphorylation (at Ser153, terminating activity), as well as negative regulation by ERK1/2 phosphorylation; it also induces p27Kip1 to coordinate cell-cycle exit with neuronal differentiation, interacts with co-activators CBP and Sp1, and in the mature nervous system is required for oculomotor/trochlear nucleus development, locus coeruleus-dependent respiratory rhythm, and anterolateral system nociceptive circuit formation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PHOX2A is a paired-like homeodomain transcription factor that specifies noradrenergic and autonomic neuronal identity during development [#0, #7]. It is positioned within a defined regulatory cascade: MASH1 acts upstream to drive Phox2a expression in noradrenergic centers and autonomic ganglia [#5], and FGF8 and BMP signals from the mid/hindbrain boundary control its induction in locus coeruleus progenitors [#7], while PHOX2B directly binds and transactivates the PHOX2A promoter [#10]; Phox2a in turn cross-regulates Phox2b at cranial ganglia, making the two factors mutually dependent in distinct contexts [#1]. Its principal transcriptional target is the dopamine-\\u03b2-hydroxylase (DBH) gene, which it activates in a noradrenergic-specific manner by binding multiple homeodomain sites in the proximal promoter\\u2014engaging PBD1 as a monomer and PBD2/PBD3 as dimers\\u2014with target selectivity such that it activates DBH but not tyrosine hydroxylase [#3, #4, #12]. Activation is synergistic with the cAMP/PKA pathway and is potentiated by the co-activator CBP, which binds the N-terminal activation domain, and by HAND2, which directly interacts with PHOX2A to enhance DBH transcription [#2, #8, #14]. PHOX2A activity is gated by phosphorylation: constitutive phosphorylation is removed by PP2A-like dephosphorylation at Ser206 to enable DNA binding, followed after a delay by PKA-dependent rephosphorylation at Ser153 that terminates activity, while ERK1/2 phosphorylation in the N-terminal domain negatively regulates target engagement [#13, #18, #21, #22]. Beyond noradrenergic enzyme genes, PHOX2A induces the cell-cycle inhibitor p27Kip1 to couple cell-cycle exit to differentiation, transactivates TLX2, and regulates the \\u03b13 nicotinic receptor subunit gene through a DNA-independent interaction with Sp1 [#19, #20, #23]. In the mature nervous system PHOX2A is required for oculomotor and trochlear nucleus development\\u2014homozygous PHOX2A mutations cause congenital fibrosis of the extraocular muscles type 2 (CFEOM2) [#11, #24]\\u2014for locus coeruleus-dependent respiratory rhythm maturation [#17], and for formation of the anterolateral system nociceptive relay from spinal cord to brain [#27, #28].\",\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"Established PHOX2A as an essential developmental regulator by showing its loss eliminates specific noradrenergic and autonomic neuronal populations and triggers apoptosis.\",\n      \"evidence\": \"Targeted Phox2a knockout mice with immunohistochemistry and in situ hybridization\",\n      \"pmids\": [\"9115735\", \"9374403\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not establish direct transcriptional targets\", \"Cross-regulation with Phox2b directionally context-dependent and not resolved mechanistically\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Identified DBH as a direct functional target and revealed that PHOX2A requires cAMP synergy rather than acting alone.\",\n      \"evidence\": \"Reporter assays with PKA cotransfection and EMSA supershift in non-neuronal cells\",\n      \"pmids\": [\"9341190\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not map the phosphorylation events linking cAMP to PHOX2A activity\", \"Mechanism of synergy not defined at the protein level\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Defined the cell-specific DNA-binding architecture of PHOX2A on the DBH promoter and demonstrated target selectivity versus tyrosine hydroxylase.\",\n      \"evidence\": \"EMSA, Southwestern, supershift, and mutant reporter constructs in noradrenergic and DBH-negative cell lines\",\n      \"pmids\": [\"9798905\", \"9763470\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Monomer vs dimer occupancy not yet resolved\", \"Co-factors mediating selectivity unknown\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Placed PHOX2A downstream of MASH1 and showed it specifies a subtype-specific, not pan-neuronal, identity program.\",\n      \"evidence\": \"Mash1 knockout in situ analysis and retroviral MASH1/Phox2a forced expression in neural crest stem cells\",\n      \"pmids\": [\"9435281\", \"9435282\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Additional targets beyond c-RET not identified\", \"Does not explain how pan-neuronal differentiation is supplied\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Demonstrated PHOX2A is both necessary and sufficient for noradrenergic neuron formation in vivo and identified FGF8/BMP as upstream inducers.\",\n      \"evidence\": \"Zebrafish soulless mutant, ectopic overexpression, and morpholino knockdown\",\n      \"pmids\": [\"10595509\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Signaling link from FGF8/BMP to Phox2a transcription not mapped\", \"Target gene readout limited to DBH/TH/Phox2b\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Mapped PHOX2A functional domains and identified CBP as a co-activator potentiating PKA-dependent transcription, plus DNA-independent multimerization.\",\n      \"evidence\": \"One- and two-hybrid assays, deletion analysis, and homeodomain-site mutagenesis\",\n      \"pmids\": [\"10644760\", \"11034547\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry and functional role of multimers in vivo unclear\", \"How N-terminal domain engages the transcription machinery not defined\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Established the regulatory loop with PHOX2B by showing PHOX2B directly binds and transactivates the PHOX2A promoter.\",\n      \"evidence\": \"EMSA, promoter deletion, and cotransfection reporter assays\",\n      \"pmids\": [\"11549713\", \"11752063\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo significance of direct binding versus genetic cross-regulation not separated\", \"Tissue specificity of the interaction not resolved\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Linked PHOX2A directly to human disease, demonstrating it is required for oculomotor and trochlear nucleus development.\",\n      \"evidence\": \"Mutation identification in four CFEOM2 pedigrees\",\n      \"pmids\": [\"11600883\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequences of individual mutations not biochemically tested at the time\", \"Target genes in oculomotor lineage not defined\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Resolved the binding mode on DBH (monomer at PBD1, dimers at PBD2/3) and tied homeodomain function to in vivo neuron development.\",\n      \"evidence\": \"EMSA with homeodomain mutants, reporter assays, and antisense injection in zebrafish\",\n      \"pmids\": [\"11948255\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Determinants of monomer vs dimer site selection not identified\", \"Broader target set not surveyed\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Showed that dephosphorylation is the switch coupling PKA signaling to PHOX2A DNA binding and transcription.\",\n      \"evidence\": \"In vivo phosphorylation assay, EMSA, reporter assays, and phosphatase inhibitor manipulation\",\n      \"pmids\": [\"11943777\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific residues not yet identified\", \"Phosphatase identity inferred but not purified\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Identified HAND2 as a direct protein partner that enhances PHOX2A-driven DBH transcription via CBP.\",\n      \"evidence\": \"Reporter assays, co-immunoprecipitation, E1A inhibition, and HD-site mutagenesis\",\n      \"pmids\": [\"14512028\", \"14506227\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the HAND2-PHOX2A interaction unknown\", \"In vivo requirement of the interaction not tested\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Demonstrated PKA/PP2A-driven dephosphorylation controls PHOX2A activity and sympathoadrenal lineage development, and that ERK1/2 phosphorylation negatively regulates it.\",\n      \"evidence\": \"Primary neural crest cultures, pharmacological inhibitors, in vitro binding, reporter assays, and chromatin association/qRT-PCR in SH-SY5Y\",\n      \"pmids\": [\"16204240\", \"16156742\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"ERK1/2 site mapping correlational in cells\", \"Integration of opposing kinase/phosphatase inputs not modeled\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Connected PHOX2A to cell-cycle exit by showing it directly induces p27Kip1 to coordinate proliferation arrest with differentiation.\",\n      \"evidence\": \"siRNA knockdown, tet-off expression, ChIP, and luciferase reporter assays in CAD and primary neural crest cells\",\n      \"pmids\": [\"16982676\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Quantitative contribution of p27Kip1 to the differentiation phenotype unclear\", \"cAMP dependence mechanism not fully resolved\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Broadened the target repertoire by establishing direct transactivation of TLX2 and a DNA-independent, Sp1-mediated mechanism at the \\u03b13 nicotinic receptor promoter.\",\n      \"evidence\": \"EMSA, ChIP, DNA pulldown, co-immunoprecipitation, and reporter assays\",\n      \"pmids\": [\"17344216\", \"17505528\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Generality of the DNA-independent Sp1 mechanism to other targets unknown\", \"In vivo relevance of TLX2 regulation not tested\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Defined a two-step phosphorylation timer that initiates and then terminates PHOX2A activity at single-residue resolution.\",\n      \"evidence\": \"Mass spectrometry, phospho-specific antibody, Ser-to-Ala/Asp mutagenesis, inducible CAD cells, and in vitro binding assays\",\n      \"pmids\": [\"19564421\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinase responsible for delayed Ser153 phosphorylation not purified\", \"How timing delay is set mechanistically unknown\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Showed PHOX2A is sufficient to drive the complete oculomotor complex program and organize the nuclear/axonal architecture.\",\n      \"evidence\": \"In ovo electroporation forced expression in chick midbrain, immunohistochemistry, axon tracing\",\n      \"pmids\": [\"20215354\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream effectors of spatial organization not identified\", \"Direct target genes in motoneuron program not enumerated\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Identified Lmx1b as an upstream regulator of Phox2a in the ventral midbrain ocular motor lineage.\",\n      \"evidence\": \"Lmx1b conditional knockout, immunohistochemistry, in situ hybridization\",\n      \"pmids\": [\"21752929\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs indirect regulation by Lmx1b not distinguished\", \"Single lab\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Revealed a new circuit role: PHOX2A is required for development of the anterolateral system relaying nociceptive signals from spinal cord to brain.\",\n      \"evidence\": \"Phox2a::Cre fate mapping, retrograde tracing, knockout analysis in mouse and human fetal spinal cord\",\n      \"pmids\": [\"33238113\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct transcriptional targets in this lineage unknown\", \"Molecular link to axon targeting not defined here\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed DCC/netrin-1 signaling downstream of PHOX2A identity in building somatotopic nociceptive maps.\",\n      \"evidence\": \"Conditional Dcc knockout in Phox2a neurons, anatomical tracing, topognosis behavior\",\n      \"pmids\": [\"36028316\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether PHOX2A directly regulates DCC not tested\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Extended PHOX2A function to modulation of itch by showing it presynaptically suppresses histamine-independent itch in lateral spinal nucleus Tac1+ neurons.\",\n      \"evidence\": \"Chemogenetics, whole-cell patch-clamp, Western blot, FISH, and behavioral assays\",\n      \"pmids\": [\"41204431\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Transcriptional targets mediating the presynaptic effect unknown\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How upstream signaling (FGF8/BMP, MASH1, Lmx1b) is mechanistically wired to PHOX2A's phosphorylation timer and how its target repertoire diversifies across noradrenergic, oculomotor, and somatosensory lineages remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No genome-wide target map across the distinct PHOX2A-dependent lineages\", \"Kinases/phosphatases acting on PHOX2A in vivo not fully identified\", \"Structural basis of monomer/dimer and Sp1/HAND2 interactions undetermined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [2, 3, 19, 20, 23, 24]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [3, 4, 12, 13, 21]},\n      {\"term_id\": \"GO:0140097\", \"supporting_discovery_ids\": []}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [13, 19, 20, 21]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0, 5, 7, 24, 27]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [2, 3, 19, 20, 23]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [17, 27, 30]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"PHOX2B\", \"CBP\", \"HAND2\", \"SP1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}