{"gene":"OSR2","run_date":"2026-04-29T11:37:57","timeline":{"discoveries":[{"year":2004,"finding":"Osr2 null mutation in mice causes a significant reduction in palatal mesenchyme proliferation specifically in the medial halves of downward-growing palatal shelves at E13.5, identifying Osr2 as a key intrinsic regulator of palatal shelf growth and patterning. Loss of Osr2 also alters expression of Osr1, Pax9, and Tgfb3 during palate development.","method":"Targeted null mutation in mice, histological analysis, in situ hybridization, cell proliferation assays","journal":"Development","confidence":"High","confidence_rationale":"Tier 2 — clean KO with defined cellular proliferation phenotype, replicated across multiple molecular markers, foundational paper with 138 citations","pmids":["15175245"],"is_preprint":false},{"year":2001,"finding":"Osr2 encodes a zinc-finger protein with 65% overall amino acid identity and 98% zinc-finger region identity to Osr1; it exists in two isoforms (three and five zinc-finger motifs) due to alternative splicing and is expressed at sites of epithelial-mesenchymal interactions during tooth and kidney development.","method":"Gene cloning, sequence analysis, whole-mount in situ hybridization, RT-PCR","journal":"Mechanisms of development","confidence":"Medium","confidence_rationale":"Tier 2 — direct molecular characterization of protein structure and expression; single lab","pmids":["11520675"],"is_preprint":false},{"year":2009,"finding":"Osr2 restricts BMP4 expression in developing tooth mesenchyme in a lingual-to-buccal gradient; Osr2-deficient mice develop supernumerary lingual teeth due to expansion of the odontogenic field, and this expansion requires Msx1 (a BMP4 feedback activator), placing Osr2 as a repressor of the BMP4-Msx1 odontogenic pathway.","method":"Osr2 knockout mice, in situ hybridization, genetic epistasis (Osr2/Msx1 double mutants)","journal":"Science","confidence":"High","confidence_rationale":"Tier 2 — genetic epistasis with double mutants, replicated with molecular marker analysis, 98 citations","pmids":["19251632"],"is_preprint":false},{"year":2009,"finding":"Osr1 and Osr2 proteins are functionally equivalent: knockin of Osr1 cDNA into the Osr2 locus fully rescues cleft palate and cranial skeletal defects of Osr2-/- mice, indicating their distinct in vivo functions result from divergent cis-regulatory sequences rather than different biochemical activities. Additionally, Osr2 controls eyelid development through regulation of the Fgf10-Fgfr2 signaling pathway.","method":"Knockin mouse generation, molecular marker analysis (in situ hybridization), genetic rescue experiments","journal":"Developmental biology","confidence":"High","confidence_rationale":"Tier 1-2 — knockin rescue with multiple orthogonal phenotypic and molecular readouts","pmids":["19389375"],"is_preprint":false},{"year":2011,"finding":"Osr2 forms stable protein complexes with the Msx1 transcription factor and interacts weakly with Pax9 protein in co-transfected cells; Osr2 acts downstream of Pax9 during tooth mesenchyme patterning, and expression of Osr2 from the Pax9 locus suppresses supernumerary tooth formation in Osr2-/- mice.","method":"Co-immunoprecipitation in co-transfected cells, gene-targeted knockin mouse strain, genetic epistasis (Osr2/Pax9 double mutants), in situ hybridization","journal":"Developmental biology","confidence":"High","confidence_rationale":"Tier 2 — protein-protein interaction by Co-IP combined with genetic epistasis and in vivo rescue","pmids":["21420399"],"is_preprint":false},{"year":2011,"finding":"Osr1 and Osr2 function redundantly to control synovial joint formation in mice; tissue-specific inactivation of Osr1 in limb mesenchyme of Osr2-/- mice causes fusion of multiple joints; Osr1/Osr2 are required for maintenance of Gdf5, Wnt4, and Wnt9b expression, and for upregulation of articular cartilage marker Prg4 in joint cells.","method":"Conditional knockout mice, genetic epistasis (double mutants), in situ hybridization for molecular markers","journal":"Developmental biology","confidence":"High","confidence_rationale":"Tier 2 — clean conditional double KO with defined joint fusion phenotype and molecular marker readouts","pmids":["21262216"],"is_preprint":false},{"year":2012,"finding":"Osr1 and Osr2 act as zinc-finger transcriptional repressors that suppress Bmp4 expression in the lateral plate mesoderm; depletion of both Osr1/Osr2 in Xenopus results in lung/trachea/esophagus agenesis due to failure to express wnt2, wnt2b, and raldh2, placing Osr1/Osr2 downstream of FGF/RA signaling and upstream of Wnt2b in lung specification.","method":"Morpholino knockdown in Xenopus, epistasis experiments, in situ hybridization, gain-of-function assays","journal":"Development","confidence":"High","confidence_rationale":"Tier 2 — genetic epistasis with multiple pathway components, Xenopus loss-of-function with defined molecular phenotypes","pmids":["22791896"],"is_preprint":false},{"year":2013,"finding":"Pax9 directly regulates Osr2 expression in the palatal mesenchyme; restoration of Osr2 expression via a Pax9(Osr2KI) knockin allele rescues posterior palate morphogenesis in Pax9 mutant embryos, placing Osr2 downstream of Pax9 in the Bmp4/Fgf10/Shh/Osr2 network controlling palatal shelf patterning.","method":"Pax9 conditional knockout, Pax9(Osr2KI) knockin rescue, in situ hybridization, genetic epistasis","journal":"Development","confidence":"High","confidence_rationale":"Tier 2 — in vivo rescue of palate morphogenesis by Osr2 knockin into Pax9 locus, multiple molecular markers","pmids":["24173808"],"is_preprint":false},{"year":2016,"finding":"Osr2 and Msx1/Bmp4 have antagonistic effects on expression of secreted Wnt antagonists Dkk2 and Sfrp2 in tooth bud mesenchyme; Osr2-dependent preferential lingual expression of Dkk2 and Sfrp2 suppresses canonical Wnt signaling, and pharmacological Wnt activation or combined DKK inhibition with Sfrp2/Sfrp3 inactivation rescues tooth morphogenesis in Msx1-/- mice.","method":"RNA-seq of tooth mesenchyme from mutant embryos, in situ hybridization, pharmacological treatments (LiCl, DKK inhibitor) in utero, genetic compound mutants","journal":"Developmental biology","confidence":"High","confidence_rationale":"Tier 1-2 — RNA-seq plus multiple orthogonal pharmacological and genetic epistasis experiments","pmids":["27713059"],"is_preprint":false},{"year":2017,"finding":"Endogenous OSR2 protein binds to the promoter regions of Sema3a and Sema3d genes in embryonic palatal mesenchyme (ChIP-PCR), and Osr2 expression represses transcription from Sema3a and Sema3d promoters in co-transfected cells. Osr2 loss leads to upregulated osteogenic pathway genes (Bmp3, Bmp5, Bmp7, Mef2c, Sox6, Sp7) and ectopic Sema3 signaling in the palatal mesenchyme.","method":"RNA-seq of palatal mesenchyme, chromatin immunoprecipitation (ChIP)-PCR, quantitative RT-PCR, in situ hybridization, co-transfection reporter assay","journal":"Journal of dental research","confidence":"High","confidence_rationale":"Tier 1-2 — direct ChIP demonstrating OSR2 binding to target gene promoters, combined with transcriptional repression assay and in vivo loss-of-function","pmids":["28731788"],"is_preprint":false},{"year":2015,"finding":"Runx2 expression is expanded in tooth bud mesenchyme in Osr2-/- mice; deletion of Osr2 partially rescues tooth morphogenesis in Runx2-/- mice (bud-to-early-bell progression) with restored Msx1 and Bmp4 expression in dental papilla, but Fgf3 and Fgf10 remain absent, indicating Runx2 controls continued tooth growth beyond cap stage independently of Osr2.","method":"Osr2-/-/Runx2-/- compound knockout mice, in situ hybridization, cell proliferation analysis","journal":"Journal of dental research","confidence":"Medium","confidence_rationale":"Tier 2 — genetic epistasis with compound knockouts and multiple molecular markers; single lab","pmids":["25916343"],"is_preprint":false},{"year":2024,"finding":"OSR2 expression in terminally exhausted CD8+ T cells is induced by coupled TCR signaling and biomechanical stress via the Piezo1/calcium/CREB axis. Mechanistically, OSR2 recruits HDAC3 to rewire the epigenetic program, suppressing cytotoxic gene expression and promoting terminal exhaustion. Depletion of Osr2 alleviates exhaustion of tumor-specific CD8+ T cells and CAR-T cells in solid tumor models.","method":"Conditional KO and forced overexpression in CD8+ T cells, Co-IP (OSR2-HDAC3 interaction), chromatin accessibility/epigenomic assays, solid tumor mouse models, pharmacological Piezo1 manipulation","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (Co-IP, epigenomics, KO, OE, in vivo models) in a high-impact single study","pmids":["38744281"],"is_preprint":false},{"year":2022,"finding":"MAX directly targets the OSR2 promoter and activates OSR2 transcription in human endometrial stromal cells (HESCs), as demonstrated by ChIP-seq, CUT&RUN-seq, and dual-luciferase reporter assays. OSR2 knockdown impairs HESC decidualization, and OSR2 overexpression partially rescues IGFBP1 expression lost upon MAX knockdown.","method":"ChIP-seq, CUT&RUN-seq, dual-luciferase reporter assay, siRNA knockdown, overexpression, MTS proliferation assay","journal":"Cell and tissue research","confidence":"High","confidence_rationale":"Tier 1-2 — direct ChIP-seq and CUT&RUN demonstrating MAX binding to OSR2 promoter, validated by reporter assay and functional rescue","pmids":["35146559"],"is_preprint":false},{"year":2025,"finding":"SOX8 transcriptionally activates OSR2 expression in ligament fibroblasts; OSR2 knockdown negates the inhibitory effects of SOX8 overexpression on osteogenic differentiation, placing OSR2 downstream of the TRIM25/SOX8 axis as a negative regulator of osteogenic differentiation.","method":"RNA-seq, GTRD analysis, dual-luciferase reporter assay, siRNA knockdown, overexpression, ALP/Alizarin Red staining, co-immunoprecipitation (TRIM25-SOX8)","journal":"JOR spine","confidence":"Medium","confidence_rationale":"Tier 2 — reporter assay and genetic epistasis (OSR2 knockdown rescue), but single lab and OSR2 is a downstream target rather than the primary focus","pmids":["40918640"],"is_preprint":false},{"year":2025,"finding":"Heterozygous loss-of-function variants in OSR2 (including nonsense, missense, and deletion) cause radioulnar synostosis in humans; functional studies demonstrated that missense variants impair nuclear localization of OSR2 protein, establishing a loss-of-function mechanism for skeletal joint fusion consistent with Osr2 knockout mouse phenotypes.","method":"Exome sequencing, chromosomal microarray, Western blot, immunofluorescence (nuclear localization assay), structural modeling","journal":"Genetics in medicine","confidence":"Medium","confidence_rationale":"Tier 2-3 — direct functional validation of nuclear localization impairment by immunofluorescence, combined with human genetics; single study","pmids":["41424369"],"is_preprint":false}],"current_model":"OSR2 is a zinc-finger transcription factor that functions as a transcriptional repressor (directly binding promoters of targets such as Sema3a, Sema3d, and Bmp4) and as a transcriptional activator (of genes like Gdf5, Wnt ligands, and Fgf10), operating downstream of Pax9 and upstream of BMP4-Msx1 and Wnt signaling pathways to control palate morphogenesis, tooth field patterning, and synovial joint formation; in CD8+ T cells, OSR2 is induced by Piezo1/calcium/CREB-mediated biomechanical signaling and recruits HDAC3 to epigenetically suppress cytotoxic gene programs, driving terminal T cell exhaustion in tumors."},"narrative":{"teleology":[{"year":2001,"claim":"Molecular cloning established OSR2 as a zinc-finger protein with two alternatively spliced isoforms, closely related to OSR1, and expressed at sites of epithelial–mesenchymal interaction during tooth and kidney development, framing it as a developmental transcription factor.","evidence":"Gene cloning, sequence analysis, whole-mount in situ hybridization, and RT-PCR in mouse embryos","pmids":["11520675"],"confidence":"Medium","gaps":["Single-lab characterization","No functional data on transcriptional activity","Protein localization beyond mRNA expression patterns not determined"]},{"year":2004,"claim":"Osr2 null mice revealed that OSR2 is required for palatal shelf growth by promoting mesenchyme proliferation in a region-specific manner, establishing its first loss-of-function phenotype and identifying cleft palate as the primary developmental consequence.","evidence":"Targeted null mutation in mice with histological analysis, cell proliferation assays, and in situ hybridization","pmids":["15175245"],"confidence":"High","gaps":["Transcriptional targets mediating the proliferation defect unknown","Mechanism of medial-lateral regionalization of OSR2 function unclear"]},{"year":2009,"claim":"Genetic epistasis using Osr2/Msx1 double mutants demonstrated that OSR2 restricts the odontogenic field by repressing BMP4 expression along a lingual-to-buccal gradient, and that supernumerary tooth formation in Osr2 knockouts depends on Msx1, placing OSR2 as an antagonist of the BMP4-Msx1 pathway. Concurrently, knockin experiments showed OSR1 and OSR2 are biochemically equivalent, with distinct in vivo roles arising from cis-regulatory divergence.","evidence":"Osr2 KO and Osr2/Msx1 double KO mice with molecular marker analysis; Osr1-into-Osr2 knockin rescue mice","pmids":["19251632","19389375"],"confidence":"High","gaps":["Direct DNA-binding targets of OSR2 not yet identified","Whether OSR2 directly represses Bmp4 transcription or acts indirectly not resolved"]},{"year":2011,"claim":"OSR2 was shown to physically interact with Msx1 and weakly with Pax9 by co-immunoprecipitation, and genetic epistasis placed OSR2 downstream of Pax9 in tooth patterning; simultaneously, redundant roles of OSR1/OSR2 in synovial joint formation were demonstrated, with double knockouts showing joint fusion and loss of Gdf5/Wnt4/Wnt9b expression.","evidence":"Co-IP in co-transfected cells, Pax9-Osr2 knockin rescue mice, conditional Osr1/Osr2 double KO in limb mesenchyme","pmids":["21420399","21262216"],"confidence":"High","gaps":["Whether OSR2-Msx1 interaction occurs on chromatin not tested","Mechanism by which OSR2 maintains joint-specific gene expression unknown","Co-IP performed in overexpression system, endogenous interaction not confirmed"]},{"year":2012,"claim":"Xenopus studies established that OSR1/OSR2 act as transcriptional repressors of Bmp4 in lateral plate mesoderm and are required upstream of Wnt2b for lung/trachea/esophagus specification, broadening OSR2 function beyond craniofacial tissues to foregut organogenesis.","evidence":"Morpholino knockdown in Xenopus with epistasis experiments and gain-of-function assays","pmids":["22791896"],"confidence":"High","gaps":["Whether OSR2 directly represses Bmp4 or acts through intermediaries in Xenopus not determined","Mammalian lung phenotype from Osr2 loss not characterized"]},{"year":2013,"claim":"Direct regulation of Osr2 by Pax9 in palatal mesenchyme was confirmed when an Osr2 knockin into the Pax9 locus rescued posterior palate morphogenesis in Pax9 mutants, solidifying the Pax9→OSR2→Bmp4/Fgf10/Shh regulatory hierarchy.","evidence":"Pax9 conditional KO, Pax9(Osr2KI) knockin rescue, in situ hybridization","pmids":["24173808"],"confidence":"High","gaps":["Whether Pax9 directly binds Osr2 cis-regulatory elements not tested by ChIP"]},{"year":2016,"claim":"RNA-seq and pharmacological rescue experiments revealed that OSR2 antagonizes canonical Wnt signaling in tooth mesenchyme by promoting expression of secreted Wnt antagonists Dkk2 and Sfrp2, and that Wnt pathway activation can bypass Msx1 loss, integrating OSR2 into the Wnt-BMP crosstalk network.","evidence":"RNA-seq of mutant tooth mesenchyme, in utero LiCl and DKK inhibitor treatment, genetic compound mutants","pmids":["27713059"],"confidence":"High","gaps":["Whether OSR2 directly activates Dkk2/Sfrp2 transcription or acts indirectly not resolved"]},{"year":2017,"claim":"ChIP-PCR demonstrated that endogenous OSR2 directly binds promoters of Sema3a and Sema3d in palatal mesenchyme and represses their transcription, providing the first direct chromatin occupancy data and identifying semaphorin signaling as a downstream effector of OSR2 in palate development.","evidence":"ChIP-PCR on embryonic palatal mesenchyme, co-transfection reporter assay, RNA-seq","pmids":["28731788"],"confidence":"High","gaps":["Genome-wide binding profile (ChIP-seq) not performed","Whether semaphorin repression is the primary mechanism preventing cleft palate not tested"]},{"year":2022,"claim":"Outside developmental contexts, MAX was shown to directly bind the OSR2 promoter and activate OSR2 transcription in human endometrial stromal cells, and OSR2 knockdown impaired decidualization, revealing a role in endometrial differentiation.","evidence":"ChIP-seq, CUT&RUN-seq, dual-luciferase reporter, siRNA knockdown and overexpression rescue in HESCs","pmids":["35146559"],"confidence":"High","gaps":["OSR2 transcriptional targets in decidualization not identified","In vivo endometrial phenotype not examined"]},{"year":2024,"claim":"A mechanistically distinct role for OSR2 in immunity was established: in terminally exhausted CD8+ T cells, Piezo1-mediated biomechanical signaling activates OSR2 via calcium/CREB, and OSR2 recruits HDAC3 to suppress cytotoxic gene programs epigenetically, with Osr2 depletion reinvigorating anti-tumor T cell responses.","evidence":"Conditional KO and overexpression in CD8+ T cells, Co-IP of OSR2-HDAC3, chromatin accessibility assays, solid tumor mouse models, pharmacological Piezo1 manipulation","pmids":["38744281"],"confidence":"High","gaps":["Genome-wide OSR2-HDAC3 co-occupancy sites not mapped","Whether OSR2 plays roles in other immune cell types unknown","Therapeutic window of OSR2 targeting in cancer immunotherapy not defined"]},{"year":2025,"claim":"Heterozygous loss-of-function OSR2 variants were identified as a cause of radioulnar synostosis in humans, with missense mutations impairing nuclear localization, directly translating the mouse joint-fusion phenotype to a human Mendelian skeletal disorder.","evidence":"Exome sequencing, chromosomal microarray, immunofluorescence for nuclear localization, Western blot","pmids":["41424369"],"confidence":"Medium","gaps":["Single study; independent replication in additional cohorts needed","Transcriptional consequences of impaired nuclear entry not characterized","Whether haploinsufficiency versus dominant-negative mechanism applies not fully resolved"]},{"year":null,"claim":"Key unresolved questions include the genome-wide direct target repertoire of OSR2 (no ChIP-seq exists), the structural basis for its dual activator/repressor function, how tissue-specific cofactor recruitment (e.g., HDAC3 in T cells versus unknown partners in mesenchyme) is determined, and whether OSR2's immunological role extends beyond CD8+ T cell exhaustion.","evidence":"","pmids":[],"confidence":"Low","gaps":["No genome-wide ChIP-seq binding map","No crystal or cryo-EM structure","Cofactor selectivity mechanism unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[1,9,12]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[2,6,9,11,12]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[1,9,14]}],"pathway":[{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0,2,3,5,6,7]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[9,11,12]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[6,8,11]},{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[11]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[11]}],"complexes":[],"partners":["MSX1","PAX9","HDAC3","RUNX2","MAX","SOX8"],"other_free_text":[]},"mechanistic_narrative":"OSR2 is a zinc-finger transcription factor that patterns developing tissues by restricting morphogenetic signaling domains and, in immune cells, epigenetically represses cytotoxic gene programs to drive T cell exhaustion. In craniofacial and tooth development, OSR2 acts downstream of Pax9 and directly binds promoters of target genes (Sema3a, Sema3d, Bmp4) to repress their transcription, thereby establishing lingual-buccal gradients that constrain the odontogenic field and prevent supernumerary tooth formation through antagonism of the BMP4-Msx1 and canonical Wnt signaling pathways [PMID:19251632, PMID:28731788, PMID:27713059]. OSR2 and its paralog OSR1 function redundantly in synovial joint maintenance—where they sustain Gdf5 and Wnt4/9b expression—and in lung specification, where they act upstream of Wnt2b [PMID:21262216, PMID:22791896]; heterozygous OSR2 loss-of-function variants cause radioulnar synostosis in humans [PMID:41424369]. In terminally exhausted CD8+ T cells within tumors, OSR2 is induced by Piezo1/calcium/CREB mechanosensory signaling and recruits the histone deacetylase HDAC3 to epigenetically silence cytotoxic effector genes, and its depletion reinvigorates anti-tumor T cell and CAR-T cell responses [PMID:38744281]."},"prefetch_data":{"uniprot":{"accession":"Q8N2R0","full_name":"Protein odd-skipped-related 2","aliases":[],"length_aa":312,"mass_kda":35.5,"function":"May be involved in the development of the mandibular molar tooth germ at the bud stage","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q8N2R0/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/OSR2","classification":"Not Classified","n_dependent_lines":3,"n_total_lines":1208,"dependency_fraction":0.0024834437086092716},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/OSR2","total_profiled":1310},"omim":[{"mim_id":"611297","title":"ODD-SKIPPED-RELATED TRANSCRIPTION FACTOR 2; OSR2","url":"https://www.omim.org/entry/611297"},{"mim_id":"608996","title":"PREMATURE OVARIAN FAILURE 3; POF3","url":"https://www.omim.org/entry/608996"},{"mim_id":"608891","title":"ODD-SKIPPED-RELATED TRANSCRIPTION FACTOR 1; OSR1","url":"https://www.omim.org/entry/608891"},{"mim_id":"605597","title":"FORKHEAD TRANSCRIPTION FACTOR FOXL2; FOXL2","url":"https://www.omim.org/entry/605597"},{"mim_id":"142983","title":"MSH HOMEOBOX 1; MSX1","url":"https://www.omim.org/entry/142983"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Plasma membrane","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"cervix","ntpm":149.8},{"tissue":"endometrium 1","ntpm":161.9},{"tissue":"fallopian tube","ntpm":151.8}],"url":"https://www.proteinatlas.org/search/OSR2"},"hgnc":{"alias_symbol":["FLJ90037"],"prev_symbol":[]},"alphafold":{"accession":"Q8N2R0","domains":[],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8N2R0","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8N2R0-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8N2R0-F1-predicted_aligned_error_v6.png","plddt_mean":60.66},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=OSR2","jax_strain_url":"https://www.jax.org/strain/search?query=OSR2"},"sequence":{"accession":"Q8N2R0","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8N2R0.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8N2R0/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8N2R0"}},"corpus_meta":[{"pmid":"15175245","id":"PMC_15175245","title":"Odd-skipped related 2 (Osr2) encodes a key intrinsic regulator of secondary palate growth and morphogenesis.","date":"2004","source":"Development (Cambridge, England)","url":"https://pubmed.ncbi.nlm.nih.gov/15175245","citation_count":138,"is_preprint":false},{"pmid":"38744281","id":"PMC_38744281","title":"Osr2 functions as a biomechanical checkpoint to aggravate CD8+ T cell exhaustion in tumor.","date":"2024","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/38744281","citation_count":115,"is_preprint":false},{"pmid":"19251632","id":"PMC_19251632","title":"Antagonistic actions of Msx1 and Osr2 pattern mammalian teeth into a single row.","date":"2009","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/19251632","citation_count":98,"is_preprint":false},{"pmid":"11520675","id":"PMC_11520675","title":"Osr2, a new mouse gene related to Drosophila odd-skipped, exhibits dynamic expression patterns during craniofacial, limb, and kidney development.","date":"2001","source":"Mechanisms of 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research","url":"https://pubmed.ncbi.nlm.nih.gov/35146559","citation_count":18,"is_preprint":false},{"pmid":"23238298","id":"PMC_23238298","title":"The odd-skipped related genes Osr1 and Osr2 are induced by 1,25-dihydroxyvitamin D3.","date":"2012","source":"The Journal of steroid biochemistry and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/23238298","citation_count":11,"is_preprint":false},{"pmid":"25916343","id":"PMC_25916343","title":"Deletion of Osr2 Partially Rescues Tooth Development in Runx2 Mutant Mice.","date":"2015","source":"Journal of dental research","url":"https://pubmed.ncbi.nlm.nih.gov/25916343","citation_count":10,"is_preprint":false},{"pmid":"40067293","id":"PMC_40067293","title":"Long Non-Coding RNA Osr2 Promotes Fusarium solani Keratitis Inflammation via the miR-30a-3p/ Xcr1 Axis.","date":"2025","source":"Investigative ophthalmology & visual science","url":"https://pubmed.ncbi.nlm.nih.gov/40067293","citation_count":1,"is_preprint":false},{"pmid":"40918640","id":"PMC_40918640","title":"TRIM25-Mediated Ubiquitination and Degradation of SOX8 Promotes Ligament Fibroblast Osteogenic Differentiation and Regulates OPLL Progression by Inhibiting OSR2 Transcription.","date":"2025","source":"JOR spine","url":"https://pubmed.ncbi.nlm.nih.gov/40918640","citation_count":0,"is_preprint":false},{"pmid":"41424369","id":"PMC_41424369","title":"Heterozygous loss of OSR2 can cause radioulnar synostosis with ancillary skeletal manifestations.","date":"2025","source":"Genetics in medicine : official journal of the American College of Medical Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/41424369","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":12146,"output_tokens":3924,"usd":0.047649},"stage2":{"model":"claude-opus-4-6","input_tokens":7320,"output_tokens":3184,"usd":0.1743},"total_usd":0.221949,"stage1_batch_id":"msgbatch_012ZiiCUBfB62NCTQd4Bk1Jo","stage2_batch_id":"msgbatch_01Xuqq9aUHoQouS7UVGZNStZ","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2004,\n      \"finding\": \"Osr2 null mutation in mice causes a significant reduction in palatal mesenchyme proliferation specifically in the medial halves of downward-growing palatal shelves at E13.5, identifying Osr2 as a key intrinsic regulator of palatal shelf growth and patterning. Loss of Osr2 also alters expression of Osr1, Pax9, and Tgfb3 during palate development.\",\n      \"method\": \"Targeted null mutation in mice, histological analysis, in situ hybridization, cell proliferation assays\",\n      \"journal\": \"Development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with defined cellular proliferation phenotype, replicated across multiple molecular markers, foundational paper with 138 citations\",\n      \"pmids\": [\"15175245\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Osr2 encodes a zinc-finger protein with 65% overall amino acid identity and 98% zinc-finger region identity to Osr1; it exists in two isoforms (three and five zinc-finger motifs) due to alternative splicing and is expressed at sites of epithelial-mesenchymal interactions during tooth and kidney development.\",\n      \"method\": \"Gene cloning, sequence analysis, whole-mount in situ hybridization, RT-PCR\",\n      \"journal\": \"Mechanisms of development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct molecular characterization of protein structure and expression; single lab\",\n      \"pmids\": [\"11520675\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Osr2 restricts BMP4 expression in developing tooth mesenchyme in a lingual-to-buccal gradient; Osr2-deficient mice develop supernumerary lingual teeth due to expansion of the odontogenic field, and this expansion requires Msx1 (a BMP4 feedback activator), placing Osr2 as a repressor of the BMP4-Msx1 odontogenic pathway.\",\n      \"method\": \"Osr2 knockout mice, in situ hybridization, genetic epistasis (Osr2/Msx1 double mutants)\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with double mutants, replicated with molecular marker analysis, 98 citations\",\n      \"pmids\": [\"19251632\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Osr1 and Osr2 proteins are functionally equivalent: knockin of Osr1 cDNA into the Osr2 locus fully rescues cleft palate and cranial skeletal defects of Osr2-/- mice, indicating their distinct in vivo functions result from divergent cis-regulatory sequences rather than different biochemical activities. Additionally, Osr2 controls eyelid development through regulation of the Fgf10-Fgfr2 signaling pathway.\",\n      \"method\": \"Knockin mouse generation, molecular marker analysis (in situ hybridization), genetic rescue experiments\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — knockin rescue with multiple orthogonal phenotypic and molecular readouts\",\n      \"pmids\": [\"19389375\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Osr2 forms stable protein complexes with the Msx1 transcription factor and interacts weakly with Pax9 protein in co-transfected cells; Osr2 acts downstream of Pax9 during tooth mesenchyme patterning, and expression of Osr2 from the Pax9 locus suppresses supernumerary tooth formation in Osr2-/- mice.\",\n      \"method\": \"Co-immunoprecipitation in co-transfected cells, gene-targeted knockin mouse strain, genetic epistasis (Osr2/Pax9 double mutants), in situ hybridization\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — protein-protein interaction by Co-IP combined with genetic epistasis and in vivo rescue\",\n      \"pmids\": [\"21420399\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Osr1 and Osr2 function redundantly to control synovial joint formation in mice; tissue-specific inactivation of Osr1 in limb mesenchyme of Osr2-/- mice causes fusion of multiple joints; Osr1/Osr2 are required for maintenance of Gdf5, Wnt4, and Wnt9b expression, and for upregulation of articular cartilage marker Prg4 in joint cells.\",\n      \"method\": \"Conditional knockout mice, genetic epistasis (double mutants), in situ hybridization for molecular markers\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean conditional double KO with defined joint fusion phenotype and molecular marker readouts\",\n      \"pmids\": [\"21262216\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Osr1 and Osr2 act as zinc-finger transcriptional repressors that suppress Bmp4 expression in the lateral plate mesoderm; depletion of both Osr1/Osr2 in Xenopus results in lung/trachea/esophagus agenesis due to failure to express wnt2, wnt2b, and raldh2, placing Osr1/Osr2 downstream of FGF/RA signaling and upstream of Wnt2b in lung specification.\",\n      \"method\": \"Morpholino knockdown in Xenopus, epistasis experiments, in situ hybridization, gain-of-function assays\",\n      \"journal\": \"Development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with multiple pathway components, Xenopus loss-of-function with defined molecular phenotypes\",\n      \"pmids\": [\"22791896\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Pax9 directly regulates Osr2 expression in the palatal mesenchyme; restoration of Osr2 expression via a Pax9(Osr2KI) knockin allele rescues posterior palate morphogenesis in Pax9 mutant embryos, placing Osr2 downstream of Pax9 in the Bmp4/Fgf10/Shh/Osr2 network controlling palatal shelf patterning.\",\n      \"method\": \"Pax9 conditional knockout, Pax9(Osr2KI) knockin rescue, in situ hybridization, genetic epistasis\",\n      \"journal\": \"Development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — in vivo rescue of palate morphogenesis by Osr2 knockin into Pax9 locus, multiple molecular markers\",\n      \"pmids\": [\"24173808\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Osr2 and Msx1/Bmp4 have antagonistic effects on expression of secreted Wnt antagonists Dkk2 and Sfrp2 in tooth bud mesenchyme; Osr2-dependent preferential lingual expression of Dkk2 and Sfrp2 suppresses canonical Wnt signaling, and pharmacological Wnt activation or combined DKK inhibition with Sfrp2/Sfrp3 inactivation rescues tooth morphogenesis in Msx1-/- mice.\",\n      \"method\": \"RNA-seq of tooth mesenchyme from mutant embryos, in situ hybridization, pharmacological treatments (LiCl, DKK inhibitor) in utero, genetic compound mutants\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — RNA-seq plus multiple orthogonal pharmacological and genetic epistasis experiments\",\n      \"pmids\": [\"27713059\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Endogenous OSR2 protein binds to the promoter regions of Sema3a and Sema3d genes in embryonic palatal mesenchyme (ChIP-PCR), and Osr2 expression represses transcription from Sema3a and Sema3d promoters in co-transfected cells. Osr2 loss leads to upregulated osteogenic pathway genes (Bmp3, Bmp5, Bmp7, Mef2c, Sox6, Sp7) and ectopic Sema3 signaling in the palatal mesenchyme.\",\n      \"method\": \"RNA-seq of palatal mesenchyme, chromatin immunoprecipitation (ChIP)-PCR, quantitative RT-PCR, in situ hybridization, co-transfection reporter assay\",\n      \"journal\": \"Journal of dental research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — direct ChIP demonstrating OSR2 binding to target gene promoters, combined with transcriptional repression assay and in vivo loss-of-function\",\n      \"pmids\": [\"28731788\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Runx2 expression is expanded in tooth bud mesenchyme in Osr2-/- mice; deletion of Osr2 partially rescues tooth morphogenesis in Runx2-/- mice (bud-to-early-bell progression) with restored Msx1 and Bmp4 expression in dental papilla, but Fgf3 and Fgf10 remain absent, indicating Runx2 controls continued tooth growth beyond cap stage independently of Osr2.\",\n      \"method\": \"Osr2-/-/Runx2-/- compound knockout mice, in situ hybridization, cell proliferation analysis\",\n      \"journal\": \"Journal of dental research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis with compound knockouts and multiple molecular markers; single lab\",\n      \"pmids\": [\"25916343\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"OSR2 expression in terminally exhausted CD8+ T cells is induced by coupled TCR signaling and biomechanical stress via the Piezo1/calcium/CREB axis. Mechanistically, OSR2 recruits HDAC3 to rewire the epigenetic program, suppressing cytotoxic gene expression and promoting terminal exhaustion. Depletion of Osr2 alleviates exhaustion of tumor-specific CD8+ T cells and CAR-T cells in solid tumor models.\",\n      \"method\": \"Conditional KO and forced overexpression in CD8+ T cells, Co-IP (OSR2-HDAC3 interaction), chromatin accessibility/epigenomic assays, solid tumor mouse models, pharmacological Piezo1 manipulation\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (Co-IP, epigenomics, KO, OE, in vivo models) in a high-impact single study\",\n      \"pmids\": [\"38744281\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"MAX directly targets the OSR2 promoter and activates OSR2 transcription in human endometrial stromal cells (HESCs), as demonstrated by ChIP-seq, CUT&RUN-seq, and dual-luciferase reporter assays. OSR2 knockdown impairs HESC decidualization, and OSR2 overexpression partially rescues IGFBP1 expression lost upon MAX knockdown.\",\n      \"method\": \"ChIP-seq, CUT&RUN-seq, dual-luciferase reporter assay, siRNA knockdown, overexpression, MTS proliferation assay\",\n      \"journal\": \"Cell and tissue research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — direct ChIP-seq and CUT&RUN demonstrating MAX binding to OSR2 promoter, validated by reporter assay and functional rescue\",\n      \"pmids\": [\"35146559\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"SOX8 transcriptionally activates OSR2 expression in ligament fibroblasts; OSR2 knockdown negates the inhibitory effects of SOX8 overexpression on osteogenic differentiation, placing OSR2 downstream of the TRIM25/SOX8 axis as a negative regulator of osteogenic differentiation.\",\n      \"method\": \"RNA-seq, GTRD analysis, dual-luciferase reporter assay, siRNA knockdown, overexpression, ALP/Alizarin Red staining, co-immunoprecipitation (TRIM25-SOX8)\",\n      \"journal\": \"JOR spine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — reporter assay and genetic epistasis (OSR2 knockdown rescue), but single lab and OSR2 is a downstream target rather than the primary focus\",\n      \"pmids\": [\"40918640\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Heterozygous loss-of-function variants in OSR2 (including nonsense, missense, and deletion) cause radioulnar synostosis in humans; functional studies demonstrated that missense variants impair nuclear localization of OSR2 protein, establishing a loss-of-function mechanism for skeletal joint fusion consistent with Osr2 knockout mouse phenotypes.\",\n      \"method\": \"Exome sequencing, chromosomal microarray, Western blot, immunofluorescence (nuclear localization assay), structural modeling\",\n      \"journal\": \"Genetics in medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — direct functional validation of nuclear localization impairment by immunofluorescence, combined with human genetics; single study\",\n      \"pmids\": [\"41424369\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"OSR2 is a zinc-finger transcription factor that functions as a transcriptional repressor (directly binding promoters of targets such as Sema3a, Sema3d, and Bmp4) and as a transcriptional activator (of genes like Gdf5, Wnt ligands, and Fgf10), operating downstream of Pax9 and upstream of BMP4-Msx1 and Wnt signaling pathways to control palate morphogenesis, tooth field patterning, and synovial joint formation; in CD8+ T cells, OSR2 is induced by Piezo1/calcium/CREB-mediated biomechanical signaling and recruits HDAC3 to epigenetically suppress cytotoxic gene programs, driving terminal T cell exhaustion in tumors.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"OSR2 is a zinc-finger transcription factor that patterns developing tissues by restricting morphogenetic signaling domains and, in immune cells, epigenetically represses cytotoxic gene programs to drive T cell exhaustion. In craniofacial and tooth development, OSR2 acts downstream of Pax9 and directly binds promoters of target genes (Sema3a, Sema3d, Bmp4) to repress their transcription, thereby establishing lingual-buccal gradients that constrain the odontogenic field and prevent supernumerary tooth formation through antagonism of the BMP4-Msx1 and canonical Wnt signaling pathways [PMID:19251632, PMID:28731788, PMID:27713059]. OSR2 and its paralog OSR1 function redundantly in synovial joint maintenance—where they sustain Gdf5 and Wnt4/9b expression—and in lung specification, where they act upstream of Wnt2b [PMID:21262216, PMID:22791896]; heterozygous OSR2 loss-of-function variants cause radioulnar synostosis in humans [PMID:41424369]. In terminally exhausted CD8+ T cells within tumors, OSR2 is induced by Piezo1/calcium/CREB mechanosensory signaling and recruits the histone deacetylase HDAC3 to epigenetically silence cytotoxic effector genes, and its depletion reinvigorates anti-tumor T cell and CAR-T cell responses [PMID:38744281].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Molecular cloning established OSR2 as a zinc-finger protein with two alternatively spliced isoforms, closely related to OSR1, and expressed at sites of epithelial–mesenchymal interaction during tooth and kidney development, framing it as a developmental transcription factor.\",\n      \"evidence\": \"Gene cloning, sequence analysis, whole-mount in situ hybridization, and RT-PCR in mouse embryos\",\n      \"pmids\": [\"11520675\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab characterization\", \"No functional data on transcriptional activity\", \"Protein localization beyond mRNA expression patterns not determined\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Osr2 null mice revealed that OSR2 is required for palatal shelf growth by promoting mesenchyme proliferation in a region-specific manner, establishing its first loss-of-function phenotype and identifying cleft palate as the primary developmental consequence.\",\n      \"evidence\": \"Targeted null mutation in mice with histological analysis, cell proliferation assays, and in situ hybridization\",\n      \"pmids\": [\"15175245\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Transcriptional targets mediating the proliferation defect unknown\", \"Mechanism of medial-lateral regionalization of OSR2 function unclear\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Genetic epistasis using Osr2/Msx1 double mutants demonstrated that OSR2 restricts the odontogenic field by repressing BMP4 expression along a lingual-to-buccal gradient, and that supernumerary tooth formation in Osr2 knockouts depends on Msx1, placing OSR2 as an antagonist of the BMP4-Msx1 pathway. Concurrently, knockin experiments showed OSR1 and OSR2 are biochemically equivalent, with distinct in vivo roles arising from cis-regulatory divergence.\",\n      \"evidence\": \"Osr2 KO and Osr2/Msx1 double KO mice with molecular marker analysis; Osr1-into-Osr2 knockin rescue mice\",\n      \"pmids\": [\"19251632\", \"19389375\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct DNA-binding targets of OSR2 not yet identified\", \"Whether OSR2 directly represses Bmp4 transcription or acts indirectly not resolved\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"OSR2 was shown to physically interact with Msx1 and weakly with Pax9 by co-immunoprecipitation, and genetic epistasis placed OSR2 downstream of Pax9 in tooth patterning; simultaneously, redundant roles of OSR1/OSR2 in synovial joint formation were demonstrated, with double knockouts showing joint fusion and loss of Gdf5/Wnt4/Wnt9b expression.\",\n      \"evidence\": \"Co-IP in co-transfected cells, Pax9-Osr2 knockin rescue mice, conditional Osr1/Osr2 double KO in limb mesenchyme\",\n      \"pmids\": [\"21420399\", \"21262216\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether OSR2-Msx1 interaction occurs on chromatin not tested\", \"Mechanism by which OSR2 maintains joint-specific gene expression unknown\", \"Co-IP performed in overexpression system, endogenous interaction not confirmed\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Xenopus studies established that OSR1/OSR2 act as transcriptional repressors of Bmp4 in lateral plate mesoderm and are required upstream of Wnt2b for lung/trachea/esophagus specification, broadening OSR2 function beyond craniofacial tissues to foregut organogenesis.\",\n      \"evidence\": \"Morpholino knockdown in Xenopus with epistasis experiments and gain-of-function assays\",\n      \"pmids\": [\"22791896\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether OSR2 directly represses Bmp4 or acts through intermediaries in Xenopus not determined\", \"Mammalian lung phenotype from Osr2 loss not characterized\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Direct regulation of Osr2 by Pax9 in palatal mesenchyme was confirmed when an Osr2 knockin into the Pax9 locus rescued posterior palate morphogenesis in Pax9 mutants, solidifying the Pax9→OSR2→Bmp4/Fgf10/Shh regulatory hierarchy.\",\n      \"evidence\": \"Pax9 conditional KO, Pax9(Osr2KI) knockin rescue, in situ hybridization\",\n      \"pmids\": [\"24173808\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Pax9 directly binds Osr2 cis-regulatory elements not tested by ChIP\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"RNA-seq and pharmacological rescue experiments revealed that OSR2 antagonizes canonical Wnt signaling in tooth mesenchyme by promoting expression of secreted Wnt antagonists Dkk2 and Sfrp2, and that Wnt pathway activation can bypass Msx1 loss, integrating OSR2 into the Wnt-BMP crosstalk network.\",\n      \"evidence\": \"RNA-seq of mutant tooth mesenchyme, in utero LiCl and DKK inhibitor treatment, genetic compound mutants\",\n      \"pmids\": [\"27713059\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether OSR2 directly activates Dkk2/Sfrp2 transcription or acts indirectly not resolved\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"ChIP-PCR demonstrated that endogenous OSR2 directly binds promoters of Sema3a and Sema3d in palatal mesenchyme and represses their transcription, providing the first direct chromatin occupancy data and identifying semaphorin signaling as a downstream effector of OSR2 in palate development.\",\n      \"evidence\": \"ChIP-PCR on embryonic palatal mesenchyme, co-transfection reporter assay, RNA-seq\",\n      \"pmids\": [\"28731788\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Genome-wide binding profile (ChIP-seq) not performed\", \"Whether semaphorin repression is the primary mechanism preventing cleft palate not tested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Outside developmental contexts, MAX was shown to directly bind the OSR2 promoter and activate OSR2 transcription in human endometrial stromal cells, and OSR2 knockdown impaired decidualization, revealing a role in endometrial differentiation.\",\n      \"evidence\": \"ChIP-seq, CUT&RUN-seq, dual-luciferase reporter, siRNA knockdown and overexpression rescue in HESCs\",\n      \"pmids\": [\"35146559\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"OSR2 transcriptional targets in decidualization not identified\", \"In vivo endometrial phenotype not examined\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"A mechanistically distinct role for OSR2 in immunity was established: in terminally exhausted CD8+ T cells, Piezo1-mediated biomechanical signaling activates OSR2 via calcium/CREB, and OSR2 recruits HDAC3 to suppress cytotoxic gene programs epigenetically, with Osr2 depletion reinvigorating anti-tumor T cell responses.\",\n      \"evidence\": \"Conditional KO and overexpression in CD8+ T cells, Co-IP of OSR2-HDAC3, chromatin accessibility assays, solid tumor mouse models, pharmacological Piezo1 manipulation\",\n      \"pmids\": [\"38744281\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Genome-wide OSR2-HDAC3 co-occupancy sites not mapped\", \"Whether OSR2 plays roles in other immune cell types unknown\", \"Therapeutic window of OSR2 targeting in cancer immunotherapy not defined\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Heterozygous loss-of-function OSR2 variants were identified as a cause of radioulnar synostosis in humans, with missense mutations impairing nuclear localization, directly translating the mouse joint-fusion phenotype to a human Mendelian skeletal disorder.\",\n      \"evidence\": \"Exome sequencing, chromosomal microarray, immunofluorescence for nuclear localization, Western blot\",\n      \"pmids\": [\"41424369\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single study; independent replication in additional cohorts needed\", \"Transcriptional consequences of impaired nuclear entry not characterized\", \"Whether haploinsufficiency versus dominant-negative mechanism applies not fully resolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the genome-wide direct target repertoire of OSR2 (no ChIP-seq exists), the structural basis for its dual activator/repressor function, how tissue-specific cofactor recruitment (e.g., HDAC3 in T cells versus unknown partners in mesenchyme) is determined, and whether OSR2's immunological role extends beyond CD8+ T cell exhaustion.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No genome-wide ChIP-seq binding map\", \"No crystal or cryo-EM structure\", \"Cofactor selectivity mechanism unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [1, 9, 12]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [2, 6, 9, 11, 12]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1, 9, 14]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0, 2, 3, 5, 6, 7]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [9, 11, 12]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [6, 8, 11]},\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [11]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [11]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"MSX1\", \"PAX9\", \"HDAC3\", \"RUNX2\", \"MAX\", \"SOX8\"],\n    \"other_free_text\": []\n  }\n}\n```"}