{"gene":"ZXDA","run_date":"2026-06-11T09:02:07","timeline":{"discoveries":[{"year":1993,"finding":"ZXDA was identified as a zinc finger gene (C2-H2 type, at least ten tandem motifs) on the proximal short arm of the human X chromosome (Xp11.21), expressed in multiple human tissues (~6.5 kb mRNA), and shown to be subject to X-inactivation.","method":"Northern blot hybridization, cDNA isolation and sequencing, X-inactivation studies","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct molecular characterization with multiple methods (Northern blot, sequencing, X-inactivation), single lab","pmids":["8268913"],"is_preprint":false},{"year":2007,"finding":"ZXDA and ZXDC form a heteromeric complex (mediated by their zinc finger domains) that interacts with the MHC II transcriptional co-activator CIITA; ZXDA knockdown and overexpression experiments demonstrated its requirement for transcriptional activation of MHC II genes. ZXDC is present at MHC II promoters before and after IFN-γ treatment.","method":"Co-immunoprecipitation, knockdown (siRNA), overexpression, chromatin immunoprecipitation (ChIP), reporter assays","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP for complex formation, ChIP for promoter occupancy, loss-of-function (knockdown) and gain-of-function (overexpression) with defined transcriptional phenotype, replicated across multiple orthogonal methods in one study","pmids":["17493635"],"is_preprint":false},{"year":2007,"finding":"ZXDA interacts with ZXDC; this interaction is not disrupted by sumoylation of ZXDC, confirming that the ZXDA–ZXDC complex is stable regardless of ZXDC sumoylation status.","method":"Co-immunoprecipitation, Western blot with anti-SUMO antibodies","journal":"Biological chemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — Co-IP confirming known interaction under sumoylation conditions, single lab, corroborates prior study","pmids":["17696781"],"is_preprint":false},{"year":2009,"finding":"A truncated ZXDC isoform (ZXDC2) interacts with both ZXDA and ZXDC and represses IFN-γ-induced MHC II transcription in HeLa cells, suggesting a competitive inhibition mechanism on the ZXDA–ZXDC–CIITA regulatory complex.","method":"Co-immunoprecipitation, reporter/transcription assays, IFN-γ treatment of HeLa cells","journal":"Molecular and cellular biochemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — Co-IP for interaction, functional transcription assay, single lab, two orthogonal methods","pmids":["19777325"],"is_preprint":false},{"year":2022,"finding":"ZXDA (and ZXDB) are substrates of the E3 ubiquitin ligase FBXO38; FBXO38 controls ZXDA/B protein stability via ubiquitination and proteasome-dependent degradation. ZXDA/B interact with the centromeric protein CENP-B, and this interaction is mutually exclusive with the ZXDA/B–FBXO38 interaction. Inappropriate stabilization of ZXDA/B leads to upregulation of centromeric chromatin-associated CENP-A and CENP-B, demonstrating a role for ZXDA/B in centromere integrity.","method":"Co-immunoprecipitation, ubiquitination assays, proteasome inhibitor treatment, proximity ligation assay, Western blot, cellular overexpression/loss-of-function","journal":"Frontiers in cell and developmental biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (Co-IP, ubiquitination assay, proteasome inhibition, functional centromere readout) in one study with mechanistic detail","pmids":["35813202"],"is_preprint":false}],"current_model":"ZXDA is a C2-H2 zinc finger protein encoded on Xp11.21 that is subject to X-inactivation; it forms a heteromeric complex with ZXDC via their zinc finger domains, and this ZXDA–ZXDC complex binds the MHC II co-activator CIITA to drive MHC II gene transcription. ZXDA protein stability is regulated by FBXO38-mediated ubiquitination and proteasomal degradation; when stabilized, ZXDA/B associate with centromeric CENP-B and elevate CENP-A/B levels, implicating ZXDA in centromere chromatin integrity."},"narrative":{"mechanistic_narrative":"ZXDA is a C2-H2 tandem zinc finger protein encoded on the proximal short arm of the X chromosome (Xp11.21) and subject to X-inactivation that functions as a transcriptional regulator of immune gene expression and a contributor to centromere chromatin integrity [PMID:8268913, PMID:17493635, PMID:35813202]. Through its zinc finger domains, ZXDA forms a heteromeric complex with its paralog ZXDC, and this complex engages the MHC class II transactivator CIITA to drive MHC II gene transcription; ZXDA is required for this transcriptional activation, and a truncated ZXDC isoform competitively represses the activity of the ZXDA-ZXDC-CIITA regulatory module [PMID:17493635, PMID:19777325]. Independently of its transcriptional role, ZXDA protein abundance is controlled by the E3 ubiquitin ligase FBXO38, which targets ZXDA for ubiquitination and proteasomal degradation; FBXO38 binding is mutually exclusive with ZXDA association with the centromeric protein CENP-B, such that stabilized ZXDA partitions to centromeres and elevates centromeric CENP-A and CENP-B levels [PMID:35813202].","teleology":[{"year":1993,"claim":"Establishing the gene's existence and basic properties answered where ZXDA resides and how it is regulated at the chromosomal level, defining it as an X-linked, X-inactivated zinc finger gene.","evidence":"cDNA isolation/sequencing, Northern blot, and X-inactivation studies of the human Xp11.21 locus","pmids":["8268913"],"confidence":"Medium","gaps":["No molecular function assigned at this stage","No binding partners or DNA targets identified","Tissue expression pattern described but not linked to a pathway"]},{"year":2007,"claim":"Identifying the ZXDA-ZXDC heterocomplex and its association with CIITA answered what protein partners ZXDA acts through and placed it in MHC II transcriptional control.","evidence":"Reciprocal Co-IP, siRNA knockdown, overexpression, ChIP, and reporter assays defining complex formation, CIITA interaction, and a transcriptional requirement","pmids":["17493635"],"confidence":"High","gaps":["Direct DNA-binding specificity of ZXDA not mapped","Stoichiometry of the ZXDA-ZXDC-CIITA complex unresolved","Whether ZXDA contributes promoter occupancy distinct from ZXDC not established"]},{"year":2007,"claim":"Testing whether ZXDC sumoylation alters the interaction answered whether the ZXDA-ZXDC complex is sensitive to this post-translational modification, showing it is stable regardless of sumoylation status.","evidence":"Co-IP combined with anti-SUMO Western blotting","pmids":["17696781"],"confidence":"Medium","gaps":["Functional consequence of ZXDC sumoylation for transcription not resolved","Corroborates but does not extend the interaction map"]},{"year":2009,"claim":"Discovery that a truncated ZXDC isoform binds ZXDA and represses MHC II transcription answered how the regulatory complex can be negatively modulated, defining a competitive inhibition mechanism.","evidence":"Co-IP and IFN-γ-induced reporter/transcription assays in HeLa cells","pmids":["19777325"],"confidence":"Medium","gaps":["Endogenous abundance and physiological relevance of the truncated isoform not quantified","Mechanism of competition at the promoter not directly visualized"]},{"year":2022,"claim":"Identifying FBXO38 as the E3 ligase for ZXDA and linking stabilized ZXDA to centromeric CENP-A/B answered how ZXDA protein levels are controlled and revealed a second, chromatin-integrity function beyond transcription.","evidence":"Co-IP, ubiquitination assays, proteasome inhibition, proximity ligation assay, and centromere readouts upon overexpression/loss-of-function","pmids":["35813202"],"confidence":"High","gaps":["How ZXDA influences CENP-A/B deposition mechanistically is unresolved","Whether the centromeric and transcriptional roles are coupled is unknown","Physiological context where FBXO38-ZXDA balance matters not defined"]},{"year":null,"claim":"The direct DNA-binding targets of ZXDA and the structural basis for its zinc-finger-mediated assembly into the ZXDC and CENP-B complexes remain undefined.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No genome-wide ZXDA binding sites mapped","No structural model of the ZXDA-ZXDC interface","Relationship between transcriptional and centromeric functions unestablished"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[1,3]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[1,4]},{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[4]}],"pathway":[{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[1,3]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[1]}],"complexes":["ZXDA-ZXDC complex"],"partners":["ZXDC","CIITA","FBXO38","CENP-B","ZXDB"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P98168","full_name":"Zinc finger X-linked protein ZXDA","aliases":[],"length_aa":799,"mass_kda":84.8,"function":"Cooperates with CIITA to promote transcription of MHC class I and MHC class II genes","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/P98168/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ZXDA","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ZXDA","total_profiled":1310},"omim":[{"mim_id":"615746","title":"ZXD FAMILY ZINC FINGER PROTEIN C; ZXDC","url":"https://www.omim.org/entry/615746"},{"mim_id":"600005","title":"CLASS II MAJOR HISTOCOMPATIBILITY COMPLEX TRANSACTIVATOR; CIITA","url":"https://www.omim.org/entry/600005"},{"mim_id":"300236","title":"ZINC FINGER-ENCODING GENE, X-LINKED, DUPLICATED, B; ZXDB","url":"https://www.omim.org/entry/300236"},{"mim_id":"300235","title":"ZINC FINGER-ENCODING GENE, X-LINKED, DUPLICATED, A; ZXDA","url":"https://www.omim.org/entry/300235"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in many","driving_tissues":[],"url":"https://www.proteinatlas.org/search/ZXDA"},"hgnc":{"alias_symbol":["ZNF896"],"prev_symbol":[]},"alphafold":{"accession":"P98168","domains":[{"cath_id":"-","chopping":"543-580","consensus_level":"medium","plddt":74.1771,"start":543,"end":580},{"cath_id":"3.30.160","chopping":"509-542","consensus_level":"medium","plddt":73.1841,"start":509,"end":542}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P98168","model_url":"https://alphafold.ebi.ac.uk/files/AF-P98168-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P98168-F1-predicted_aligned_error_v6.png","plddt_mean":54.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ZXDA","jax_strain_url":"https://www.jax.org/strain/search?query=ZXDA"},"sequence":{"accession":"P98168","fasta_url":"https://rest.uniprot.org/uniprotkb/P98168.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P98168/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P98168"}},"corpus_meta":[{"pmid":"10196364","id":"PMC_10196364","title":"Generation of an approximately 2.4 Mb human X centromere-based minichromosome by targeted telomere-associated chromosome fragmentation in DT40.","date":"1999","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/10196364","citation_count":89,"is_preprint":false},{"pmid":"8079992","id":"PMC_8079992","title":"The severe phenotype of females with tiny ring X chromosomes is associated with inability of these chromosomes to undergo X inactivation.","date":"1994","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/8079992","citation_count":70,"is_preprint":false},{"pmid":"8554051","id":"PMC_8554051","title":"Molecular definition of breakpoints associated with human Xq isochromosomes: implications for mechanisms of formation.","date":"1996","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/8554051","citation_count":68,"is_preprint":false},{"pmid":"11896455","id":"PMC_11896455","title":"Lack of expression of XIST from a small ring X chromosome containing the XIST locus in a girl with short stature, facial dysmorphism and developmental delay.","date":"2002","source":"European journal of human genetics : EJHG","url":"https://pubmed.ncbi.nlm.nih.gov/11896455","citation_count":31,"is_preprint":false},{"pmid":"8268913","id":"PMC_8268913","title":"Duplicated zinc finger protein genes on the proximal short arm of the human X chromosome: isolation, characterization and X-inactivation studies.","date":"1993","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/8268913","citation_count":30,"is_preprint":false},{"pmid":"23236494","id":"PMC_23236494","title":"X-linked gene transcription patterns in female and male in vivo, in vitro and cloned porcine individual blastocysts.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23236494","citation_count":24,"is_preprint":false},{"pmid":"17493635","id":"PMC_17493635","title":"The zinc finger proteins ZXDA and ZXDC form a complex that binds CIITA and regulates MHC II gene transcription.","date":"2007","source":"Journal of molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/17493635","citation_count":23,"is_preprint":false},{"pmid":"9832041","id":"PMC_9832041","title":"Severe phenotype resulting from an active ring X chromosome in a female with a complex karyotype: characterisation and replication study.","date":"1998","source":"Journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/9832041","citation_count":12,"is_preprint":false},{"pmid":"17696781","id":"PMC_17696781","title":"Sumoylation of the zinc finger protein ZXDC enhances the function of its transcriptional activation domain.","date":"2007","source":"Biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17696781","citation_count":7,"is_preprint":false},{"pmid":"35813202","id":"PMC_35813202","title":"FBXO38 Ubiquitin Ligase Controls Centromere Integrity via ZXDA/B Stability.","date":"2022","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/35813202","citation_count":5,"is_preprint":false},{"pmid":"19777325","id":"PMC_19777325","title":"An N- and C-terminal truncated isoform of zinc finger X-linked duplicated C protein represses MHC class II transcription.","date":"2009","source":"Molecular and cellular biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19777325","citation_count":4,"is_preprint":false},{"pmid":"20684234","id":"PMC_20684234","title":"[Changes in genes expression caused by overexpression of the transcription factor ZXDC in embryonic kidney cell line HEK293].","date":"2010","source":"Ukrains'kyi biokhimichnyi zhurnal (1999 )","url":"https://pubmed.ncbi.nlm.nih.gov/20684234","citation_count":1,"is_preprint":false},{"pmid":"36211459","id":"PMC_36211459","title":"Erratum: FBXO38 ubiquitin ligase controls centromere integrity via ZXDA/B stability.","date":"2022","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/36211459","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7512,"output_tokens":1382,"usd":0.021633,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8044,"output_tokens":2152,"usd":0.04701,"stage2_stop_reason":"end_turn"},"total_usd":0.068643,"stage1_batch_id":"msgbatch_01UT1AahFPCAyn2uVweS7A9z","stage2_batch_id":"msgbatch_01HuKWtKNT4Pqj1bc8eEP5RV","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1993,\n      \"finding\": \"ZXDA was identified as a zinc finger gene (C2-H2 type, at least ten tandem motifs) on the proximal short arm of the human X chromosome (Xp11.21), expressed in multiple human tissues (~6.5 kb mRNA), and shown to be subject to X-inactivation.\",\n      \"method\": \"Northern blot hybridization, cDNA isolation and sequencing, X-inactivation studies\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct molecular characterization with multiple methods (Northern blot, sequencing, X-inactivation), single lab\",\n      \"pmids\": [\"8268913\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"ZXDA and ZXDC form a heteromeric complex (mediated by their zinc finger domains) that interacts with the MHC II transcriptional co-activator CIITA; ZXDA knockdown and overexpression experiments demonstrated its requirement for transcriptional activation of MHC II genes. ZXDC is present at MHC II promoters before and after IFN-γ treatment.\",\n      \"method\": \"Co-immunoprecipitation, knockdown (siRNA), overexpression, chromatin immunoprecipitation (ChIP), reporter assays\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP for complex formation, ChIP for promoter occupancy, loss-of-function (knockdown) and gain-of-function (overexpression) with defined transcriptional phenotype, replicated across multiple orthogonal methods in one study\",\n      \"pmids\": [\"17493635\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"ZXDA interacts with ZXDC; this interaction is not disrupted by sumoylation of ZXDC, confirming that the ZXDA–ZXDC complex is stable regardless of ZXDC sumoylation status.\",\n      \"method\": \"Co-immunoprecipitation, Western blot with anti-SUMO antibodies\",\n      \"journal\": \"Biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — Co-IP confirming known interaction under sumoylation conditions, single lab, corroborates prior study\",\n      \"pmids\": [\"17696781\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"A truncated ZXDC isoform (ZXDC2) interacts with both ZXDA and ZXDC and represses IFN-γ-induced MHC II transcription in HeLa cells, suggesting a competitive inhibition mechanism on the ZXDA–ZXDC–CIITA regulatory complex.\",\n      \"method\": \"Co-immunoprecipitation, reporter/transcription assays, IFN-γ treatment of HeLa cells\",\n      \"journal\": \"Molecular and cellular biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — Co-IP for interaction, functional transcription assay, single lab, two orthogonal methods\",\n      \"pmids\": [\"19777325\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"ZXDA (and ZXDB) are substrates of the E3 ubiquitin ligase FBXO38; FBXO38 controls ZXDA/B protein stability via ubiquitination and proteasome-dependent degradation. ZXDA/B interact with the centromeric protein CENP-B, and this interaction is mutually exclusive with the ZXDA/B–FBXO38 interaction. Inappropriate stabilization of ZXDA/B leads to upregulation of centromeric chromatin-associated CENP-A and CENP-B, demonstrating a role for ZXDA/B in centromere integrity.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, proteasome inhibitor treatment, proximity ligation assay, Western blot, cellular overexpression/loss-of-function\",\n      \"journal\": \"Frontiers in cell and developmental biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (Co-IP, ubiquitination assay, proteasome inhibition, functional centromere readout) in one study with mechanistic detail\",\n      \"pmids\": [\"35813202\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ZXDA is a C2-H2 zinc finger protein encoded on Xp11.21 that is subject to X-inactivation; it forms a heteromeric complex with ZXDC via their zinc finger domains, and this ZXDA–ZXDC complex binds the MHC II co-activator CIITA to drive MHC II gene transcription. ZXDA protein stability is regulated by FBXO38-mediated ubiquitination and proteasomal degradation; when stabilized, ZXDA/B associate with centromeric CENP-B and elevate CENP-A/B levels, implicating ZXDA in centromere chromatin integrity.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"ZXDA is a C2-H2 tandem zinc finger protein encoded on the proximal short arm of the X chromosome (Xp11.21) and subject to X-inactivation that functions as a transcriptional regulator of immune gene expression and a contributor to centromere chromatin integrity [#0, #1, #4]. Through its zinc finger domains, ZXDA forms a heteromeric complex with its paralog ZXDC, and this complex engages the MHC class II transactivator CIITA to drive MHC II gene transcription; ZXDA is required for this transcriptional activation, and a truncated ZXDC isoform competitively represses the activity of the ZXDA-ZXDC-CIITA regulatory module [#1, #3]. Independently of its transcriptional role, ZXDA protein abundance is controlled by the E3 ubiquitin ligase FBXO38, which targets ZXDA for ubiquitination and proteasomal degradation; FBXO38 binding is mutually exclusive with ZXDA association with the centromeric protein CENP-B, such that stabilized ZXDA partitions to centromeres and elevates centromeric CENP-A and CENP-B levels [#4].\",\n  \"teleology\": [\n    {\n      \"year\": 1993,\n      \"claim\": \"Establishing the gene's existence and basic properties answered where ZXDA resides and how it is regulated at the chromosomal level, defining it as an X-linked, X-inactivated zinc finger gene.\",\n      \"evidence\": \"cDNA isolation/sequencing, Northern blot, and X-inactivation studies of the human Xp11.21 locus\",\n      \"pmids\": [\"8268913\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No molecular function assigned at this stage\", \"No binding partners or DNA targets identified\", \"Tissue expression pattern described but not linked to a pathway\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Identifying the ZXDA-ZXDC heterocomplex and its association with CIITA answered what protein partners ZXDA acts through and placed it in MHC II transcriptional control.\",\n      \"evidence\": \"Reciprocal Co-IP, siRNA knockdown, overexpression, ChIP, and reporter assays defining complex formation, CIITA interaction, and a transcriptional requirement\",\n      \"pmids\": [\"17493635\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct DNA-binding specificity of ZXDA not mapped\", \"Stoichiometry of the ZXDA-ZXDC-CIITA complex unresolved\", \"Whether ZXDA contributes promoter occupancy distinct from ZXDC not established\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Testing whether ZXDC sumoylation alters the interaction answered whether the ZXDA-ZXDC complex is sensitive to this post-translational modification, showing it is stable regardless of sumoylation status.\",\n      \"evidence\": \"Co-IP combined with anti-SUMO Western blotting\",\n      \"pmids\": [\"17696781\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of ZXDC sumoylation for transcription not resolved\", \"Corroborates but does not extend the interaction map\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Discovery that a truncated ZXDC isoform binds ZXDA and represses MHC II transcription answered how the regulatory complex can be negatively modulated, defining a competitive inhibition mechanism.\",\n      \"evidence\": \"Co-IP and IFN-\\u03b3-induced reporter/transcription assays in HeLa cells\",\n      \"pmids\": [\"19777325\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endogenous abundance and physiological relevance of the truncated isoform not quantified\", \"Mechanism of competition at the promoter not directly visualized\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Identifying FBXO38 as the E3 ligase for ZXDA and linking stabilized ZXDA to centromeric CENP-A/B answered how ZXDA protein levels are controlled and revealed a second, chromatin-integrity function beyond transcription.\",\n      \"evidence\": \"Co-IP, ubiquitination assays, proteasome inhibition, proximity ligation assay, and centromere readouts upon overexpression/loss-of-function\",\n      \"pmids\": [\"35813202\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How ZXDA influences CENP-A/B deposition mechanistically is unresolved\", \"Whether the centromeric and transcriptional roles are coupled is unknown\", \"Physiological context where FBXO38-ZXDA balance matters not defined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The direct DNA-binding targets of ZXDA and the structural basis for its zinc-finger-mediated assembly into the ZXDC and CENP-B complexes remain undefined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No genome-wide ZXDA binding sites mapped\", \"No structural model of the ZXDA-ZXDC interface\", \"Relationship between transcriptional and centromeric functions unestablished\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [1, 3]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1, 4]},\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [1, 3]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"complexes\": [\"ZXDA-ZXDC complex\"],\n    \"partners\": [\"ZXDC\", \"CIITA\", \"FBXO38\", \"CENP-B\", \"ZXDB\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":3,"faith_total":3,"faith_pct":100.0}}