{"gene":"TEX12","run_date":"2026-04-28T21:42:58","timeline":{"discoveries":[{"year":2006,"finding":"TEX12 is a meiosis-specific component of the central element of the synaptonemal complex that depends on the transverse filament protein SYCP1 for localization to meiotic chromosomes, and specifically co-precipitates with SYCE2, suggesting TEX12 and SYCE2 form a complex that interacts with SYCE1.","method":"Co-immunoprecipitation, co-localization by immunofluorescence, mouse knockout models","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP plus multiple knockout models, replicated across labs","pmids":["16968740"],"is_preprint":false},{"year":2008,"finding":"TEX12 is essential for propagation of synapsis along paired homologous chromosomes and for maturation of early recombination events into crossovers; in Tex12-/- meiocytes, the central element is disrupted and synapsis initiates but fails to propagate.","method":"Tex12 gene knockout in mouse (both male and female), structural analysis of synaptonemal complex","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 — clean KO with defined cellular and structural phenotype, in both sexes","pmids":["18611960"],"is_preprint":false},{"year":2012,"finding":"PLK1 directly phosphorylates TEX12 (and SYCP1) in vitro, and PLK1-mediated phosphorylation of central element proteins is required for their removal from the synaptonemal complex during the prophase-to-metaphase I transition in mouse spermatocytes.","method":"In vitro phosphorylation assay with PLK1/2/3/4, PLK inhibitor (BI 2536) treatment of pachytene spermatocytes ex vivo, okadaic acid-induced meiotic prophase exit assay","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 1 — in vitro kinase assay plus pharmacological inhibition with defined phenotypic readout","pmids":["22854038"],"is_preprint":false},{"year":2012,"finding":"Human SYCE2 and TEX12 form a highly stable constitutive equimolar hetero-octameric complex (SYCE2 tetramer + two TEX12 dimers) that self-assembles into filamentous structures resembling the central element, as revealed by biochemical reconstitution and electron microscopy.","method":"Biochemical reconstitution, biophysical analysis (analytical ultracentrifugation, gel filtration), electron microscopy","journal":"Open biology","confidence":"High","confidence_rationale":"Tier 1 — reconstituted complex with structural EM, multiple orthogonal biophysical methods","pmids":["22870393"],"is_preprint":false},{"year":2016,"finding":"Disruption of SYCE2 and TEX12 localization to the central element abolishes central alignment of the N-terminal region of SYCP1, demonstrating that all four central element proteins interdependently contribute to forming a bilayered transverse-filament-central-element junction structure.","method":"Immunoelectron microscopy with protein interaction data in mouse spermatocytes","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 — immunoelectron microscopy with functional disruption showing structural consequence","pmids":["27103161"],"is_preprint":false},{"year":2021,"finding":"X-ray crystal structures of human SYCE2-TEX12 reveal that building blocks are 2:2 coiled coils that dimerize into 4:4 hetero-oligomers, which interact end-to-end and laterally to form 10-nm fibers that intertwine into 40-nm bundled micrometer-long fibers defining the SC midline, analogous to intermediate filament assembly.","method":"X-ray crystallography, mutagenesis, biophysics, electron microscopy","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 — crystal structures combined with mutagenesis, biophysics, and EM in a single study","pmids":["34373646"],"is_preprint":false},{"year":2021,"finding":"TEX12 localises to centrosomes during meiosis independently of chromosome synapsis, and ectopic somatic expression of TEX12 similarly localises to centrosomes causing centrosome amplification; phosphorylation of TEX12 on tyrosine 48 is required for centrosome amplification but not for TEX12 recruitment to centrosomes.","method":"Immunofluorescence localization, ectopic expression in somatic cells, structure-function mutagenesis (Y48 phosphorylation), cancer cell proliferation assays","journal":"Communications biology","confidence":"High","confidence_rationale":"Tier 2 — direct localization experiments with functional consequence, mutagenesis defining phosphorylation site","pmids":["34880391"],"is_preprint":false},{"year":2021,"finding":"The mammalian TEX11 (Zip4 ortholog) interacts with SC central element protein TEX12, suggesting a conserved mechanism directly coupling crossover formation to synaptonemal complex assembly.","method":"Co-immunoprecipitation/interaction assay (reported as part of broader study in yeast and mammals)","journal":"Genes & development","confidence":"Medium","confidence_rationale":"Tier 3 — single Co-IP in mammalian cells, supporting a conserved mechanism shown by genetic epistasis in yeast","pmids":["34969823"],"is_preprint":false},{"year":2022,"finding":"X-ray crystal structures of TEX12 mutants in three conformations reveal a wild-type dimeric four-helical coiled-coil structure; the C-terminal tip sequence responsible for driving SYCE2-TEX12 fiber assembly also controls the oligomeric state and conformation of isolated TEX12, providing structural basis for SYCE2-independent roles of TEX12.","method":"X-ray crystallography, solution light scattering and X-ray scattering (SAXS), C-terminal tip mutagenesis","journal":"Communications biology","confidence":"High","confidence_rationale":"Tier 1 — crystal structures in multiple conformations with mutagenesis and solution scattering","pmids":["36071143"],"is_preprint":false},{"year":2023,"finding":"SYCE3 interacts with the CE complex SYCE2-TEX12, providing a mechanism for SYCE2-TEX12 recruitment during SC assembly following SYCE3-mediated remodeling of the SYCP1 lattice.","method":"Biochemical interaction assays, separation-of-function mutagenesis in mice","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1–2 — biochemical interaction plus in vivo mutagenesis demonstrating recruitment mechanism","pmids":["36635604"],"is_preprint":false}],"current_model":"TEX12 is a meiosis-specific synaptonemal complex central element protein that forms a stable 2:2 coiled-coil hetero-oligomeric complex with SYCE2, which hierarchically assembles into intermediate-filament-like fibers that structurally underpin synaptic elongation along meiotic chromosomes; TEX12 is essential for propagation of synapsis and crossover maturation, is phosphorylated by PLK1 to trigger SC disassembly at meiotic prophase exit, and additionally localizes to meiotic centrosomes where phosphorylation of Y48 drives centrosome amplification when aberrantly expressed in somatic/cancer cells."},"narrative":{"teleology":[{"year":2006,"claim":"Identifying TEX12 as a central element component that physically associates with SYCE2 established its molecular address within the SC and its partnership hierarchy.","evidence":"Co-immunoprecipitation, immunofluorescence co-localization, and mouse knockout models","pmids":["16968740"],"confidence":"High","gaps":["Stoichiometry and direct binding mode of the TEX12–SYCE2 complex were unknown","Whether TEX12 has functions independent of the central element was unaddressed"]},{"year":2008,"claim":"Genetic ablation showed that TEX12 is not required for synapsis initiation but is essential for its propagation along chromosomes and for crossover maturation, defining its specific functional role within SC assembly.","evidence":"Tex12 knockout mice (male and female), structural analysis of the SC in mutant meiocytes","pmids":["18611960"],"confidence":"High","gaps":["Molecular mechanism by which TEX12 drives synapsis propagation was unclear","Whether TEX12 directly participates in recombination or acts indirectly through SC structure was unknown"]},{"year":2012,"claim":"Biochemical reconstitution revealed that SYCE2 and TEX12 form a stable equimolar hetero-oligomeric complex that self-assembles into filaments resembling the central element, establishing the structural building block of the SC midline.","evidence":"Reconstitution with analytical ultracentrifugation, gel filtration, and electron microscopy of human SYCE2–TEX12","pmids":["22870393"],"confidence":"High","gaps":["Atomic-resolution structure of the SYCE2–TEX12 complex was lacking","The assembly hierarchy connecting filament formation to the transverse filament lattice was unknown"]},{"year":2012,"claim":"Demonstrating that PLK1 directly phosphorylates TEX12 and that PLK activity is required for central element disassembly at meiotic prophase exit revealed the signal controlling SC dismantling.","evidence":"In vitro kinase assays with PLK1–4, PLK inhibitor (BI 2536) treatment of pachytene spermatocytes, okadaic acid–induced prophase exit","pmids":["22854038"],"confidence":"High","gaps":["Specific phosphorylation sites on TEX12 responsible for disassembly were not mapped","Whether phosphorylation destabilizes TEX12–SYCE2 filaments directly or acts through additional effectors was untested"]},{"year":2016,"claim":"Immunoelectron microscopy showed that SYCE2–TEX12 disruption abolishes central alignment of SYCP1 N-termini, establishing that all central element proteins interdependently form the bilayered transverse-filament junction.","evidence":"Immunoelectron microscopy with functional disruption in mouse spermatocytes","pmids":["27103161"],"confidence":"High","gaps":["Exact contact interfaces between SYCE2–TEX12 fibers and SYCP1 N-termini were unresolved"]},{"year":2021,"claim":"Crystal structures of SYCE2–TEX12 revealed the 2:2 coiled-coil building block and its hierarchical assembly into 10-nm and bundled 40-nm fibers via end-to-end and lateral interactions, analogous to intermediate filament polymerization, providing the atomic-resolution mechanism for SC midline formation.","evidence":"X-ray crystallography, mutagenesis, biophysics, and electron microscopy of human SYCE2–TEX12","pmids":["34373646"],"confidence":"High","gaps":["In vivo validation of assembly-defective mutants in mouse meiosis was not reported","How the fiber lattice integrates with other CE components (SYCE1, SYCE3, SIX6OS1) structurally was incomplete"]},{"year":2021,"claim":"Discovery that TEX12 localizes to meiotic centrosomes independently of synapsis and that ectopic somatic expression drives centrosome amplification dependent on Y48 phosphorylation revealed a SC-independent function relevant to cancer-testis antigen biology.","evidence":"Immunofluorescence, ectopic expression in somatic/cancer cells, Y48 phospho-mutant analysis","pmids":["34880391"],"confidence":"High","gaps":["The kinase responsible for Y48 phosphorylation was not identified","Whether centrosomal TEX12 contributes to normal meiotic spindle function was not determined"]},{"year":2021,"claim":"Interaction between TEX11 (Zip4 ortholog) and TEX12 suggested a direct molecular coupling between crossover designation and SC central element assembly.","evidence":"Co-immunoprecipitation in mammalian cells, supported by genetic epistasis in yeast","pmids":["34969823"],"confidence":"Medium","gaps":["Single Co-IP without reciprocal validation in mammalian system","Binding interface and functional consequence of the TEX11–TEX12 interaction were not characterized"]},{"year":2022,"claim":"Structures of TEX12 alone in multiple conformations showed that its C-terminal tip controls both oligomeric state and fiber-driving capacity, providing a structural basis for potential SYCE2-independent roles such as centrosome function.","evidence":"X-ray crystallography, SAXS, solution light scattering, and C-terminal tip mutagenesis of TEX12","pmids":["36071143"],"confidence":"High","gaps":["Whether the C-terminal tip conformational switch operates in the centrosomal context was untested","Functional consequence of TEX12 oligomeric state in vivo was not assessed"]},{"year":2023,"claim":"Demonstrating that SYCE3 directly interacts with the SYCE2–TEX12 complex and is required for its recruitment to the SC defined the upstream assembly step linking transverse filament remodeling to central element fiber formation.","evidence":"Biochemical interaction assays and separation-of-function mutagenesis in mice","pmids":["36635604"],"confidence":"High","gaps":["Structural basis of the SYCE3–SYCE2/TEX12 interface at atomic resolution was not determined","Whether SYCE3-mediated recruitment is the sole pathway or whether redundant recruitment mechanisms exist is unknown"]},{"year":null,"claim":"Key open questions include identifying the kinase and functional role of TEX12 Y48 phosphorylation at centrosomes, mapping the specific PLK1 phosphosites that trigger SC disassembly, and determining whether TEX12's SYCE2-independent oligomeric states serve distinct functions at centrosomes versus chromosomes.","evidence":"","pmids":[],"confidence":"High","gaps":["Kinase for Y48 phosphorylation at centrosomes is unknown","PLK1 phosphosites on TEX12 are unmapped","In vivo relevance of TEX12 C-terminal tip conformational switch remains untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[3,5,8]}],"localization":[{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[0,1,4]},{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[6]}],"pathway":[{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[1,2]},{"term_id":"R-HSA-1474165","term_label":"Reproduction","supporting_discovery_ids":[0,1]}],"complexes":["SYCE2-TEX12 central element complex"],"partners":["SYCE2","SYCE3","SYCP1","TEX11","PLK1","SYCE1"],"other_free_text":[]},"mechanistic_narrative":"TEX12 is a meiosis-specific structural protein of the synaptonemal complex (SC) central element that is essential for propagation of chromosome synapsis and crossover maturation during meiotic prophase. TEX12 forms a 2:2 coiled-coil heterodimer with SYCE2 that hierarchically assembles through end-to-end and lateral interactions into intermediate-filament-like fibers defining the SC midline; this complex is recruited to the SC lattice through interaction with SYCE3 following SYCE3-mediated remodeling of the SYCP1 transverse filament [PMID:22870393, PMID:34373646, PMID:36635604]. PLK1 phosphorylates TEX12 to drive removal of central element proteins from the SC during the prophase-to-metaphase I transition [PMID:22854038]. TEX12 also localizes to meiotic centrosomes independently of synapsis, and ectopic somatic expression causes centrosome amplification dependent on phosphorylation of tyrosine 48, providing a mechanistic link to cancer-testis antigen biology [PMID:34880391]."},"prefetch_data":{"uniprot":{"accession":"Q9BXU0","full_name":"Testis-expressed protein 12","aliases":[],"length_aa":123,"mass_kda":14.1,"function":"Component of the transverse central element of synaptonemal complexes (SCS), formed between homologous chromosomes during meiotic prophase (By similarity). Requires SYCP1 in order to be incorporated into the central element (By similarity)","subcellular_location":"Chromosome","url":"https://www.uniprot.org/uniprotkb/Q9BXU0/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/TEX12","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/TEX12","total_profiled":1310},"omim":[{"mim_id":"618968","title":"CHROMOSOME 1 OPEN READING FRAME 146; C1ORF146","url":"https://www.omim.org/entry/618968"},{"mim_id":"605791","title":"TESTIS-EXPRESSED GENE 12; TEX12","url":"https://www.omim.org/entry/605791"},{"mim_id":"300311","title":"TESTIS-EXPRESSED GENE 11; TEX11","url":"https://www.omim.org/entry/300311"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Centrosome","reliability":"Supported"},{"location":"Basal body","reliability":"Supported"}],"tissue_specificity":"Group enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"retina","ntpm":8.0},{"tissue":"testis","ntpm":19.3}],"url":"https://www.proteinatlas.org/search/TEX12"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q9BXU0","domains":[],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BXU0","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BXU0-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BXU0-F1-predicted_aligned_error_v6.png","plddt_mean":79.75},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=TEX12","jax_strain_url":"https://www.jax.org/strain/search?query=TEX12"},"sequence":{"accession":"Q9BXU0","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9BXU0.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9BXU0/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BXU0"}},"corpus_meta":[{"pmid":"16968740","id":"PMC_16968740","title":"Characterization of a novel meiosis-specific protein within the central element of the synaptonemal complex.","date":"2006","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/16968740","citation_count":126,"is_preprint":false},{"pmid":"18611960","id":"PMC_18611960","title":"Progression of meiotic recombination requires structural maturation of the central element of the synaptonemal complex.","date":"2008","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/18611960","citation_count":100,"is_preprint":false},{"pmid":"22854038","id":"PMC_22854038","title":"Polo-like kinase is required for synaptonemal complex disassembly and phosphorylation in mouse spermatocytes.","date":"2012","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/22854038","citation_count":82,"is_preprint":false},{"pmid":"18802461","id":"PMC_18802461","title":"Corona is required for higher-order assembly of transverse filaments into full-length synaptonemal complex in Drosophila oocytes.","date":"2008","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/18802461","citation_count":63,"is_preprint":false},{"pmid":"22870393","id":"PMC_22870393","title":"Structural analysis of the human SYCE2-TEX12 complex provides molecular insights into synaptonemal complex assembly.","date":"2012","source":"Open biology","url":"https://pubmed.ncbi.nlm.nih.gov/22870393","citation_count":49,"is_preprint":false},{"pmid":"30607510","id":"PMC_30607510","title":"Molecular structure of human synaptonemal complex protein SYCE1.","date":"2019","source":"Chromosoma","url":"https://pubmed.ncbi.nlm.nih.gov/30607510","citation_count":35,"is_preprint":false},{"pmid":"34969823","id":"PMC_34969823","title":"The Zip4 protein directly couples meiotic crossover formation to synaptonemal complex assembly.","date":"2021","source":"Genes & development","url":"https://pubmed.ncbi.nlm.nih.gov/34969823","citation_count":35,"is_preprint":false},{"pmid":"27103161","id":"PMC_27103161","title":"The central element of the synaptonemal complex in mice is organized as a bilayered junction structure.","date":"2016","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/27103161","citation_count":33,"is_preprint":false},{"pmid":"29934299","id":"PMC_29934299","title":"Two Tabersonine 6,7-Epoxidases Initiate Lochnericine-Derived Alkaloid Biosynthesis in Catharanthus roseus.","date":"2018","source":"Plant physiology","url":"https://pubmed.ncbi.nlm.nih.gov/29934299","citation_count":32,"is_preprint":false},{"pmid":"34373646","id":"PMC_34373646","title":"Structural basis of meiotic chromosome synaptic elongation through hierarchical fibrous assembly of SYCE2-TEX12.","date":"2021","source":"Nature structural & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/34373646","citation_count":31,"is_preprint":false},{"pmid":"31023827","id":"PMC_31023827","title":"A molecular model for self-assembly of the synaptonemal complex protein SYCE3.","date":"2019","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/31023827","citation_count":28,"is_preprint":false},{"pmid":"29932616","id":"PMC_29932616","title":"Expression analysis of genes encoding TEX11, TEX12, TEX14 and TEX15 in testis tissues of men with non-obstructive azoospermia.","date":"2018","source":"JBRA assisted reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/29932616","citation_count":27,"is_preprint":false},{"pmid":"36635604","id":"PMC_36635604","title":"Structural maturation of SYCP1-mediated meiotic chromosome synapsis by SYCE3.","date":"2023","source":"Nature structural & molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/36635604","citation_count":19,"is_preprint":false},{"pmid":"34880391","id":"PMC_34880391","title":"Centrosome dysfunction associated with somatic expression of the synaptonemal complex protein TEX12.","date":"2021","source":"Communications 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TEX12 and conformational regulation by its C-terminal tip.","date":"2022","source":"Communications biology","url":"https://pubmed.ncbi.nlm.nih.gov/36071143","citation_count":6,"is_preprint":false},{"pmid":"29957214","id":"PMC_29957214","title":"Cryo-electron tomography of SYCP3 fibers under native conditions.","date":"2018","source":"Methods in cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/29957214","citation_count":1,"is_preprint":false},{"pmid":"37012491","id":"PMC_37012491","title":"A Novel Frameshift Microdeletion of the TEX12 Gene Caused Infertility in Two Brothers with Nonobstructive Azoospermia.","date":"2023","source":"Reproductive sciences (Thousand Oaks, Calif.)","url":"https://pubmed.ncbi.nlm.nih.gov/37012491","citation_count":0,"is_preprint":false},{"pmid":"41467312","id":"PMC_41467312","title":"SOX30 Governs Synaptonemal Complex Assembly and Homologous Recombination in Male Meiosis.","date":"2025","source":"Cell proliferation","url":"https://pubmed.ncbi.nlm.nih.gov/41467312","citation_count":0,"is_preprint":false},{"pmid":"40332359","id":"PMC_40332359","title":"Single-Cell Transcriptomic Analysis of the Potential Mechanisms of Follicular Development in Stra8-Deficient Mice.","date":"2025","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/40332359","citation_count":0,"is_preprint":false},{"pmid":"41537827","id":"PMC_41537827","title":"Synaptonemal complex assembly in yeast depends on a 2:2 Ecm11-Gmc2 heterocomplex.","date":"2025","source":"Open biology","url":"https://pubmed.ncbi.nlm.nih.gov/41537827","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":11225,"output_tokens":2193,"usd":0.033285},"stage2":{"model":"claude-opus-4-6","input_tokens":5501,"output_tokens":2583,"usd":0.13812},"total_usd":0.171405,"stage1_batch_id":"msgbatch_01RPbVc9PDH9zQmYK5Hs6srm","stage2_batch_id":"msgbatch_01JVbVLzeKN2yVrsGp3zC8aM","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2006,\n      \"finding\": \"TEX12 is a meiosis-specific component of the central element of the synaptonemal complex that depends on the transverse filament protein SYCP1 for localization to meiotic chromosomes, and specifically co-precipitates with SYCE2, suggesting TEX12 and SYCE2 form a complex that interacts with SYCE1.\",\n      \"method\": \"Co-immunoprecipitation, co-localization by immunofluorescence, mouse knockout models\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP plus multiple knockout models, replicated across labs\",\n      \"pmids\": [\"16968740\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"TEX12 is essential for propagation of synapsis along paired homologous chromosomes and for maturation of early recombination events into crossovers; in Tex12-/- meiocytes, the central element is disrupted and synapsis initiates but fails to propagate.\",\n      \"method\": \"Tex12 gene knockout in mouse (both male and female), structural analysis of synaptonemal complex\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with defined cellular and structural phenotype, in both sexes\",\n      \"pmids\": [\"18611960\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"PLK1 directly phosphorylates TEX12 (and SYCP1) in vitro, and PLK1-mediated phosphorylation of central element proteins is required for their removal from the synaptonemal complex during the prophase-to-metaphase I transition in mouse spermatocytes.\",\n      \"method\": \"In vitro phosphorylation assay with PLK1/2/3/4, PLK inhibitor (BI 2536) treatment of pachytene spermatocytes ex vivo, okadaic acid-induced meiotic prophase exit assay\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro kinase assay plus pharmacological inhibition with defined phenotypic readout\",\n      \"pmids\": [\"22854038\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Human SYCE2 and TEX12 form a highly stable constitutive equimolar hetero-octameric complex (SYCE2 tetramer + two TEX12 dimers) that self-assembles into filamentous structures resembling the central element, as revealed by biochemical reconstitution and electron microscopy.\",\n      \"method\": \"Biochemical reconstitution, biophysical analysis (analytical ultracentrifugation, gel filtration), electron microscopy\",\n      \"journal\": \"Open biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstituted complex with structural EM, multiple orthogonal biophysical methods\",\n      \"pmids\": [\"22870393\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Disruption of SYCE2 and TEX12 localization to the central element abolishes central alignment of the N-terminal region of SYCP1, demonstrating that all four central element proteins interdependently contribute to forming a bilayered transverse-filament-central-element junction structure.\",\n      \"method\": \"Immunoelectron microscopy with protein interaction data in mouse spermatocytes\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — immunoelectron microscopy with functional disruption showing structural consequence\",\n      \"pmids\": [\"27103161\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"X-ray crystal structures of human SYCE2-TEX12 reveal that building blocks are 2:2 coiled coils that dimerize into 4:4 hetero-oligomers, which interact end-to-end and laterally to form 10-nm fibers that intertwine into 40-nm bundled micrometer-long fibers defining the SC midline, analogous to intermediate filament assembly.\",\n      \"method\": \"X-ray crystallography, mutagenesis, biophysics, electron microscopy\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structures combined with mutagenesis, biophysics, and EM in a single study\",\n      \"pmids\": [\"34373646\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"TEX12 localises to centrosomes during meiosis independently of chromosome synapsis, and ectopic somatic expression of TEX12 similarly localises to centrosomes causing centrosome amplification; phosphorylation of TEX12 on tyrosine 48 is required for centrosome amplification but not for TEX12 recruitment to centrosomes.\",\n      \"method\": \"Immunofluorescence localization, ectopic expression in somatic cells, structure-function mutagenesis (Y48 phosphorylation), cancer cell proliferation assays\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct localization experiments with functional consequence, mutagenesis defining phosphorylation site\",\n      \"pmids\": [\"34880391\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"The mammalian TEX11 (Zip4 ortholog) interacts with SC central element protein TEX12, suggesting a conserved mechanism directly coupling crossover formation to synaptonemal complex assembly.\",\n      \"method\": \"Co-immunoprecipitation/interaction assay (reported as part of broader study in yeast and mammals)\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single Co-IP in mammalian cells, supporting a conserved mechanism shown by genetic epistasis in yeast\",\n      \"pmids\": [\"34969823\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"X-ray crystal structures of TEX12 mutants in three conformations reveal a wild-type dimeric four-helical coiled-coil structure; the C-terminal tip sequence responsible for driving SYCE2-TEX12 fiber assembly also controls the oligomeric state and conformation of isolated TEX12, providing structural basis for SYCE2-independent roles of TEX12.\",\n      \"method\": \"X-ray crystallography, solution light scattering and X-ray scattering (SAXS), C-terminal tip mutagenesis\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structures in multiple conformations with mutagenesis and solution scattering\",\n      \"pmids\": [\"36071143\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SYCE3 interacts with the CE complex SYCE2-TEX12, providing a mechanism for SYCE2-TEX12 recruitment during SC assembly following SYCE3-mediated remodeling of the SYCP1 lattice.\",\n      \"method\": \"Biochemical interaction assays, separation-of-function mutagenesis in mice\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — biochemical interaction plus in vivo mutagenesis demonstrating recruitment mechanism\",\n      \"pmids\": [\"36635604\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"TEX12 is a meiosis-specific synaptonemal complex central element protein that forms a stable 2:2 coiled-coil hetero-oligomeric complex with SYCE2, which hierarchically assembles into intermediate-filament-like fibers that structurally underpin synaptic elongation along meiotic chromosomes; TEX12 is essential for propagation of synapsis and crossover maturation, is phosphorylated by PLK1 to trigger SC disassembly at meiotic prophase exit, and additionally localizes to meiotic centrosomes where phosphorylation of Y48 drives centrosome amplification when aberrantly expressed in somatic/cancer cells.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"TEX12 is a meiosis-specific structural protein of the synaptonemal complex (SC) central element that is essential for propagation of chromosome synapsis and crossover maturation during meiotic prophase. TEX12 forms a 2:2 coiled-coil heterodimer with SYCE2 that hierarchically assembles through end-to-end and lateral interactions into intermediate-filament-like fibers defining the SC midline; this complex is recruited to the SC lattice through interaction with SYCE3 following SYCE3-mediated remodeling of the SYCP1 transverse filament [PMID:22870393, PMID:34373646, PMID:36635604]. PLK1 phosphorylates TEX12 to drive removal of central element proteins from the SC during the prophase-to-metaphase I transition [PMID:22854038]. TEX12 also localizes to meiotic centrosomes independently of synapsis, and ectopic somatic expression causes centrosome amplification dependent on phosphorylation of tyrosine 48, providing a mechanistic link to cancer-testis antigen biology [PMID:34880391].\",\n  \"teleology\": [\n    {\n      \"year\": 2006,\n      \"claim\": \"Identifying TEX12 as a central element component that physically associates with SYCE2 established its molecular address within the SC and its partnership hierarchy.\",\n      \"evidence\": \"Co-immunoprecipitation, immunofluorescence co-localization, and mouse knockout models\",\n      \"pmids\": [\"16968740\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Stoichiometry and direct binding mode of the TEX12–SYCE2 complex were unknown\",\n        \"Whether TEX12 has functions independent of the central element was unaddressed\"\n      ]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Genetic ablation showed that TEX12 is not required for synapsis initiation but is essential for its propagation along chromosomes and for crossover maturation, defining its specific functional role within SC assembly.\",\n      \"evidence\": \"Tex12 knockout mice (male and female), structural analysis of the SC in mutant meiocytes\",\n      \"pmids\": [\"18611960\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Molecular mechanism by which TEX12 drives synapsis propagation was unclear\",\n        \"Whether TEX12 directly participates in recombination or acts indirectly through SC structure was unknown\"\n      ]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Biochemical reconstitution revealed that SYCE2 and TEX12 form a stable equimolar hetero-oligomeric complex that self-assembles into filaments resembling the central element, establishing the structural building block of the SC midline.\",\n      \"evidence\": \"Reconstitution with analytical ultracentrifugation, gel filtration, and electron microscopy of human SYCE2–TEX12\",\n      \"pmids\": [\"22870393\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Atomic-resolution structure of the SYCE2–TEX12 complex was lacking\",\n        \"The assembly hierarchy connecting filament formation to the transverse filament lattice was unknown\"\n      ]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Demonstrating that PLK1 directly phosphorylates TEX12 and that PLK activity is required for central element disassembly at meiotic prophase exit revealed the signal controlling SC dismantling.\",\n      \"evidence\": \"In vitro kinase assays with PLK1–4, PLK inhibitor (BI 2536) treatment of pachytene spermatocytes, okadaic acid–induced prophase exit\",\n      \"pmids\": [\"22854038\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Specific phosphorylation sites on TEX12 responsible for disassembly were not mapped\",\n        \"Whether phosphorylation destabilizes TEX12–SYCE2 filaments directly or acts through additional effectors was untested\"\n      ]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Immunoelectron microscopy showed that SYCE2–TEX12 disruption abolishes central alignment of SYCP1 N-termini, establishing that all central element proteins interdependently form the bilayered transverse-filament junction.\",\n      \"evidence\": \"Immunoelectron microscopy with functional disruption in mouse spermatocytes\",\n      \"pmids\": [\"27103161\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Exact contact interfaces between SYCE2–TEX12 fibers and SYCP1 N-termini were unresolved\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Crystal structures of SYCE2–TEX12 revealed the 2:2 coiled-coil building block and its hierarchical assembly into 10-nm and bundled 40-nm fibers via end-to-end and lateral interactions, analogous to intermediate filament polymerization, providing the atomic-resolution mechanism for SC midline formation.\",\n      \"evidence\": \"X-ray crystallography, mutagenesis, biophysics, and electron microscopy of human SYCE2–TEX12\",\n      \"pmids\": [\"34373646\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"In vivo validation of assembly-defective mutants in mouse meiosis was not reported\",\n        \"How the fiber lattice integrates with other CE components (SYCE1, SYCE3, SIX6OS1) structurally was incomplete\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Discovery that TEX12 localizes to meiotic centrosomes independently of synapsis and that ectopic somatic expression drives centrosome amplification dependent on Y48 phosphorylation revealed a SC-independent function relevant to cancer-testis antigen biology.\",\n      \"evidence\": \"Immunofluorescence, ectopic expression in somatic/cancer cells, Y48 phospho-mutant analysis\",\n      \"pmids\": [\"34880391\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The kinase responsible for Y48 phosphorylation was not identified\",\n        \"Whether centrosomal TEX12 contributes to normal meiotic spindle function was not determined\"\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Interaction between TEX11 (Zip4 ortholog) and TEX12 suggested a direct molecular coupling between crossover designation and SC central element assembly.\",\n      \"evidence\": \"Co-immunoprecipitation in mammalian cells, supported by genetic epistasis in yeast\",\n      \"pmids\": [\"34969823\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single Co-IP without reciprocal validation in mammalian system\",\n        \"Binding interface and functional consequence of the TEX11–TEX12 interaction were not characterized\"\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Structures of TEX12 alone in multiple conformations showed that its C-terminal tip controls both oligomeric state and fiber-driving capacity, providing a structural basis for potential SYCE2-independent roles such as centrosome function.\",\n      \"evidence\": \"X-ray crystallography, SAXS, solution light scattering, and C-terminal tip mutagenesis of TEX12\",\n      \"pmids\": [\"36071143\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether the C-terminal tip conformational switch operates in the centrosomal context was untested\",\n        \"Functional consequence of TEX12 oligomeric state in vivo was not assessed\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Demonstrating that SYCE3 directly interacts with the SYCE2–TEX12 complex and is required for its recruitment to the SC defined the upstream assembly step linking transverse filament remodeling to central element fiber formation.\",\n      \"evidence\": \"Biochemical interaction assays and separation-of-function mutagenesis in mice\",\n      \"pmids\": [\"36635604\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis of the SYCE3–SYCE2/TEX12 interface at atomic resolution was not determined\",\n        \"Whether SYCE3-mediated recruitment is the sole pathway or whether redundant recruitment mechanisms exist is unknown\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key open questions include identifying the kinase and functional role of TEX12 Y48 phosphorylation at centrosomes, mapping the specific PLK1 phosphosites that trigger SC disassembly, and determining whether TEX12's SYCE2-independent oligomeric states serve distinct functions at centrosomes versus chromosomes.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Kinase for Y48 phosphorylation at centrosomes is unknown\",\n        \"PLK1 phosphosites on TEX12 are unmapped\",\n        \"In vivo relevance of TEX12 C-terminal tip conformational switch remains untested\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [3, 5, 8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [0, 1, 4]},\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"complexes\": [\n      \"SYCE2-TEX12 central element complex\"\n    ],\n    \"partners\": [\n      \"SYCE2\",\n      \"SYCE3\",\n      \"SYCP1\",\n      \"TEX11\",\n      \"PLK1\",\n      \"SYCE1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}