{"gene":"GGN","run_date":"2026-06-10T01:55:21","timeline":{"discoveries":[{"year":2003,"finding":"GGN1 and GGN3, two proteins produced by alternate splicing of the Ggn (gametogenetin) gene, interact with POG (the product of the Pog gene) via yeast two-hybrid screening. The three GGN isoforms (GGN1, GGN2, GGN3) have distinct subcellular localizations: GGN1 along the nuclear membrane, GGN2 in the cytoplasm, and GGN3 in the nucleus/nucleoli. Co-expression of POG with GGN1 or GGN3 in HeLa cells redirected POG localization to the perinuclear region or nucleoli, respectively, demonstrating that GGN isoforms regulate POG subcellular localization.","method":"Yeast two-hybrid screening, subcellular localization by transfection/imaging in HeLa cells, co-expression experiments","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid plus co-expression localization rescue in HeLa cells, single lab, two complementary methods","pmids":["12574169"],"is_preprint":false},{"year":2003,"finding":"Ggn expression is confined to late pachytene spermatocytes and round spermatids, temporally coinciding with meiosis. POG-deficient mice show impaired meiosis, and Ggn/Pog co-expression in primary spermatocytes implicates GGN in spermatogenesis downstream of POG.","method":"Expression analysis in mouse testis; genetic loss-of-function (Pog-deficient mice) with meiotic phenotype readout","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mouse knockout phenotype combined with expression timing analysis, single lab","pmids":["12574169"],"is_preprint":false},{"year":2013,"finding":"GGN1 (the largest isoform) interacts with the DNA repair proteins FANCL, FANCD2, and BRCC36 in mouse testis, as demonstrated by co-immunoprecipitation. Complete loss of GGN (Ggn null mice) causes pre-implantation embryonic lethality with no viable blastocysts. Heterozygous Ggn knockout pachytene spermatocytes show an increased incidence of unrepaired DNA double-strand breaks (DSBs), placing GGN in the Fanconi Anemia/BRCA DNA repair pathway during male meiosis.","method":"Co-immunoprecipitation from mouse testis lysate; Ggn null mouse generation; immunostaining for DSB markers in pachytene spermatocytes of heterozygous knockouts; RT-PCR for Ggn expression in oocytes and pre-implantation embryos","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP identifying multiple binding partners, combined with clean knockout mouse showing two distinct phenotypes (embryonic lethality, meiotic DSB repair defect), single lab but multiple orthogonal methods","pmids":["23451117"],"is_preprint":false},{"year":2013,"finding":"A homozygous truncating variant in GGN was identified by whole-exome sequencing in one patient with globozoospermia (round-headed spermatozoa lacking an acrosome), confirming that loss-of-function of GGN can cause this spermatogenic defect in humans.","method":"Whole-exome sequencing in a cohort of 69 globozoospermia patients","journal":"Human genetics","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single patient with a truncating variant identified by WES, no functional validation in this paper","pmids":["33108537"],"is_preprint":false},{"year":2019,"finding":"Knockdown of GGN in colorectal cancer (CRC) cell lines inhibited cellular proliferation and promoted apoptosis, and was associated with reduced phospho-Akt levels, placing GGN upstream of the PI3K/Akt signaling pathway in this context.","method":"siRNA knockdown of GGN in CRC cell lines; proliferation and apoptosis assays; Western blotting for p-Akt","journal":"Pathology oncology research : POR","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single knockdown experiment with pathway readout but no rescue or mutagenesis to confirm specificity","pmids":["30721393"],"is_preprint":false}],"current_model":"GGN (Gametogenetin) is a testis-enriched protein expressed in late pachytene spermatocytes and round spermatids that exists as multiple splice isoforms (GGN1, GGN2, GGN3) with distinct subcellular localizations; GGN1 physically interacts with the DNA repair proteins FANCL, FANCD2, and BRCC36, and loss of GGN in mice causes pre-implantation embryonic lethality and increased unrepaired meiotic DNA double-strand breaks, implicating GGN in the Fanconi Anemia/BRCA DNA repair pathway during spermatogenesis; GGN also interacts with and regulates the localization of POG, a regulator of primordial germ cell proliferation."},"narrative":{"mechanistic_narrative":"GGN (Gametogenetin) is a testis-enriched protein expressed in late pachytene spermatocytes and round spermatids that functions in DNA double-strand break repair during male meiosis [PMID:12574169, PMID:23451117]. The Ggn locus produces three splice isoforms (GGN1, GGN2, GGN3) with distinct subcellular distributions—GGN1 at the nuclear membrane, GGN2 cytoplasmic, and GGN3 nuclear/nucleolar—and these isoforms regulate the subcellular localization of their interaction partner POG, redirecting it to the perinuclear region or nucleoli [PMID:12574169]. GGN1, the largest isoform, physically associates with the Fanconi Anemia/BRCA DNA repair proteins FANCL, FANCD2, and BRCC36; complete loss of GGN in mice causes pre-implantation embryonic lethality, while heterozygous spermatocytes accumulate unrepaired meiotic DNA double-strand breaks, placing GGN within the FA/BRCA repair pathway [PMID:23451117]. A homozygous truncating variant in human GGN was identified in a patient with globozoospermia, linking GGN loss-of-function to this spermatogenic defect [PMID:33108537].","teleology":[{"year":2003,"claim":"Established GGN as a POG-interacting protein whose splice isoforms control POG subcellular localization, providing the first molecular handle on GGN function in germ cells.","evidence":"Yeast two-hybrid screening with co-expression localization assays in HeLa cells","pmids":["12574169"],"confidence":"Medium","gaps":["Interaction shown in heterologous HeLa system, not in germ cells","Functional consequence of POG relocalization not defined","No structural basis for isoform-specific localization"]},{"year":2003,"claim":"Linked GGN expression to the timing of meiosis and to spermatogenesis downstream of POG, framing GGN as a germ-cell-stage-specific factor.","evidence":"Expression analysis in mouse testis combined with Pog-deficient mouse meiotic phenotype","pmids":["12574169"],"confidence":"Medium","gaps":["Causal role of GGN itself in meiosis not directly tested here","Mechanism connecting POG to meiotic progression unknown"]},{"year":2013,"claim":"Defined a mechanistic role for GGN in meiotic DNA repair by showing GGN1 binds FA/BRCA pathway proteins and that GGN loss disrupts double-strand break repair and is embryonically essential.","evidence":"Co-immunoprecipitation from mouse testis, Ggn null mouse generation, and DSB-marker immunostaining in heterozygous pachytene spermatocytes","pmids":["23451117"],"confidence":"High","gaps":["Embryonic lethality of nulls prevented direct assessment of meiotic phenotype in homozygotes","Biochemical step within the FA/BRCA pathway performed by GGN not defined","Whether interactions are direct vs. complex-mediated not resolved"]},{"year":2013,"claim":"Connected GGN loss-of-function to a human spermatogenic disease phenotype, extending its germ-cell role to clinical infertility.","evidence":"Whole-exome sequencing of a globozoospermia cohort identifying a homozygous truncating variant in one patient","pmids":["33108537"],"confidence":"Low","gaps":["Single patient with no functional validation","Causality not established beyond genetic association","Mechanism linking GGN loss to acrosome failure unknown"]},{"year":2019,"claim":"Raised a possible context-dependent role for GGN in cell survival signaling outside the germ line, in colorectal cancer cells.","evidence":"siRNA knockdown in CRC cell lines with proliferation, apoptosis, and p-Akt readouts","pmids":["30721393"],"confidence":"Low","gaps":["Single knockdown without rescue or mutagenesis to confirm specificity","Direct molecular link between GGN and PI3K/Akt not established","Relationship to germ-cell DNA repair role unclear"]},{"year":null,"claim":"The precise biochemical activity of GGN within the FA/BRCA repair pathway and the functional significance of its isoform-specific localizations remain undefined.","evidence":"","pmids":[],"confidence":"Low","gaps":["No enzymatic or structural activity assigned to GGN","Mechanism by which GGN promotes DSB repair unresolved","Whether POG and FA/BRCA interactions are part of one functional axis is unknown"]}],"mechanism_profile":{"molecular_activity":[],"localization":[{"term_id":"GO:0005635","term_label":"nuclear envelope","supporting_discovery_ids":[0]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0]},{"term_id":"GO:0005730","term_label":"nucleolus","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[2]},{"term_id":"R-HSA-1474165","term_label":"Reproduction","supporting_discovery_ids":[1,2]}],"complexes":[],"partners":["POG","FANCL","FANCD2","BRCC36"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q86UU5","full_name":"Gametogenetin","aliases":[],"length_aa":652,"mass_kda":66.7,"function":"May be involved in spermatogenesis","subcellular_location":"","url":"https://www.uniprot.org/uniprotkb/Q86UU5/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GGN","classification":"Not Classified","n_dependent_lines":86,"n_total_lines":1208,"dependency_fraction":0.07119205298013245},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/GGN","total_profiled":1310},"omim":[{"mim_id":"619826","title":"SPERMATOGENIC FAILURE 69; SPGF69","url":"https://www.omim.org/entry/619826"},{"mim_id":"613958","title":"SPERMATOGENIC FAILURE 9; SPGF9","url":"https://www.omim.org/entry/613958"},{"mim_id":"613893","title":"DPY19-LIKE 2; DPY19L2","url":"https://www.omim.org/entry/613893"},{"mim_id":"609966","title":"GAMETOGENETIN; GGN","url":"https://www.omim.org/entry/609966"},{"mim_id":"600473","title":"PURINE-RICH ELEMENT-BINDING PROTEIN A; PURA","url":"https://www.omim.org/entry/600473"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Golgi apparatus","reliability":"Approved"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"testis","ntpm":90.1}],"url":"https://www.proteinatlas.org/search/GGN"},"hgnc":{"alias_symbol":["FLJ35713","MGC33369"],"prev_symbol":[]},"alphafold":{"accession":"Q86UU5","domains":[{"cath_id":"-","chopping":"622-647","consensus_level":"medium","plddt":64.1062,"start":622,"end":647}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q86UU5","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q86UU5-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q86UU5-F1-predicted_aligned_error_v6.png","plddt_mean":44.03},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GGN","jax_strain_url":"https://www.jax.org/strain/search?query=GGN"},"sequence":{"accession":"Q86UU5","fasta_url":"https://rest.uniprot.org/uniprotkb/Q86UU5.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q86UU5/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q86UU5"}},"corpus_meta":[{"pmid":"11016637","id":"PMC_11016637","title":"Polymorphic 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hospitalaria","url":"https://pubmed.ncbi.nlm.nih.gov/26667715","citation_count":6,"is_preprint":false},{"pmid":"29044734","id":"PMC_29044734","title":"Association of androgen receptor gene CAG and GGN repeat polymorphism with cryptorchidism: A meta-analysis.","date":"2017","source":"Andrologia","url":"https://pubmed.ncbi.nlm.nih.gov/29044734","citation_count":5,"is_preprint":false},{"pmid":"39487084","id":"PMC_39487084","title":"GGN-GO: geometric graph networks for predicting protein function by multi-scale structure features.","date":"2024","source":"Briefings in bioinformatics","url":"https://pubmed.ncbi.nlm.nih.gov/39487084","citation_count":5,"is_preprint":false},{"pmid":"25027083","id":"PMC_25027083","title":"Associations between androgen receptor CAG & GGN repeat polymorphism & recurrent spontaneous abortions in Chinese women.","date":"2014","source":"The Indian journal of medical research","url":"https://pubmed.ncbi.nlm.nih.gov/25027083","citation_count":5,"is_preprint":false},{"pmid":"26221130","id":"PMC_26221130","title":"Association of androgen receptor GGN repeat length polymorphism and male infertility in Khuzestan, Iran.","date":"2015","source":"Iranian journal of reproductive medicine","url":"https://pubmed.ncbi.nlm.nih.gov/26221130","citation_count":4,"is_preprint":false},{"pmid":"27626686","id":"PMC_27626686","title":"Androgen receptor CAG and GGN repeat length variation contributes more to the tumorigenesis of osteosarcoma.","date":"2016","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/27626686","citation_count":2,"is_preprint":false},{"pmid":"27873769","id":"PMC_27873769","title":"Androgen receptor gene CAG and GGN repeat lengths as predictors of recovery of spermatogenesis following testicular germ cell cancer treatment.","date":"2017","source":"Asian journal of andrology","url":"https://pubmed.ncbi.nlm.nih.gov/27873769","citation_count":2,"is_preprint":false},{"pmid":"23744333","id":"PMC_23744333","title":"[Polymorphisms of (CAG)n and(GGN)n repeats of androgen receptor gene among ethnic Hui and Han Chinese from Ningxia].","date":"2013","source":"Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23744333","citation_count":2,"is_preprint":false},{"pmid":"37377277","id":"PMC_37377277","title":"CAG and GGN repeat polymorphisms in the androgen receptor gene of a Chilean pediatric cohort with idiopathic inguinal cryptorchidism.","date":"2023","source":"Andrology","url":"https://pubmed.ncbi.nlm.nih.gov/37377277","citation_count":1,"is_preprint":false},{"pmid":"26609967","id":"PMC_26609967","title":"Androgen receptor CAG and GGN repeat polymorphisms influence performance in boys and girls.","date":"2015","source":"The Journal of sports medicine and physical fitness","url":"https://pubmed.ncbi.nlm.nih.gov/26609967","citation_count":1,"is_preprint":false},{"pmid":"30721393","id":"PMC_30721393","title":"GGN Promotes Tumorigenesis by Regulating Proliferation and Apoptosis in Colorectal Cancer.","date":"2019","source":"Pathology oncology research : POR","url":"https://pubmed.ncbi.nlm.nih.gov/30721393","citation_count":1,"is_preprint":false},{"pmid":"38831467","id":"PMC_38831467","title":"Does clinical T1N0 GGN really require checking for distant metastasis during initial staging for lung cancer?","date":"2024","source":"Cancer imaging : the official publication of the International Cancer Imaging Society","url":"https://pubmed.ncbi.nlm.nih.gov/38831467","citation_count":1,"is_preprint":false},{"pmid":"39395345","id":"PMC_39395345","title":"gGN: Representing the Gene Ontology as low-rank Gaussian distributions.","date":"2024","source":"Computers in biology and medicine","url":"https://pubmed.ncbi.nlm.nih.gov/39395345","citation_count":0,"is_preprint":false},{"pmid":"29714466","id":"PMC_29714466","title":"The relation between isolated micropenis in childhood with CAG and GGN repeat polymorphisms in the androgen receptor gene.","date":"2018","source":"Turkish journal of medical sciences","url":"https://pubmed.ncbi.nlm.nih.gov/29714466","citation_count":0,"is_preprint":false},{"pmid":"40031964","id":"PMC_40031964","title":"GGN repeat length of the androgen receptor gene is associated with antral follicle count in Chinese women undergoing controlled ovarian stimulation.","date":"2025","source":"Nan fang yi ke da xue xue bao = Journal of Southern Medical University","url":"https://pubmed.ncbi.nlm.nih.gov/40031964","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":33533,"output_tokens":1739,"usd":0.063342,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8151,"output_tokens":2001,"usd":0.04539,"stage2_stop_reason":"end_turn"},"total_usd":0.108732,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"Looking through the abstracts, I need to identify papers about the canonical GGN protein (Gametogenetin) vs. papers about the GGN repeat in the androgen receptor gene (which is a different entity - a microsatellite repeat in the AR gene, not the GGN gene/protein itself).\n\nThe query gene is **GGN** (also known as FLJ35713, MGC33369), which encodes Gametogenetin - a testis-enriched protein involved in spermatogenesis.\n\nPapers [14], [37], [57], and [16] are about the actual GGN protein/gene (Gametogenetin). The vast majority of other papers are about the GGN trinucleotide repeat in the androgen receptor gene - a completely different entity. Papers [3], [6], [13], [36], [49], [58], [59] are about other genes/topics that collide on \"GGN.\"\n\nLet me extract mechanistic findings from papers [14], [37], [57], and [16]:\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2003,\n      \"finding\": \"GGN1 and GGN3, two proteins produced by alternate splicing of the Ggn (gametogenetin) gene, interact with POG (the product of the Pog gene) via yeast two-hybrid screening. The three GGN isoforms (GGN1, GGN2, GGN3) have distinct subcellular localizations: GGN1 along the nuclear membrane, GGN2 in the cytoplasm, and GGN3 in the nucleus/nucleoli. Co-expression of POG with GGN1 or GGN3 in HeLa cells redirected POG localization to the perinuclear region or nucleoli, respectively, demonstrating that GGN isoforms regulate POG subcellular localization.\",\n      \"method\": \"Yeast two-hybrid screening, subcellular localization by transfection/imaging in HeLa cells, co-expression experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid plus co-expression localization rescue in HeLa cells, single lab, two complementary methods\",\n      \"pmids\": [\"12574169\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Ggn expression is confined to late pachytene spermatocytes and round spermatids, temporally coinciding with meiosis. POG-deficient mice show impaired meiosis, and Ggn/Pog co-expression in primary spermatocytes implicates GGN in spermatogenesis downstream of POG.\",\n      \"method\": \"Expression analysis in mouse testis; genetic loss-of-function (Pog-deficient mice) with meiotic phenotype readout\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mouse knockout phenotype combined with expression timing analysis, single lab\",\n      \"pmids\": [\"12574169\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"GGN1 (the largest isoform) interacts with the DNA repair proteins FANCL, FANCD2, and BRCC36 in mouse testis, as demonstrated by co-immunoprecipitation. Complete loss of GGN (Ggn null mice) causes pre-implantation embryonic lethality with no viable blastocysts. Heterozygous Ggn knockout pachytene spermatocytes show an increased incidence of unrepaired DNA double-strand breaks (DSBs), placing GGN in the Fanconi Anemia/BRCA DNA repair pathway during male meiosis.\",\n      \"method\": \"Co-immunoprecipitation from mouse testis lysate; Ggn null mouse generation; immunostaining for DSB markers in pachytene spermatocytes of heterozygous knockouts; RT-PCR for Ggn expression in oocytes and pre-implantation embryos\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP identifying multiple binding partners, combined with clean knockout mouse showing two distinct phenotypes (embryonic lethality, meiotic DSB repair defect), single lab but multiple orthogonal methods\",\n      \"pmids\": [\"23451117\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"A homozygous truncating variant in GGN was identified by whole-exome sequencing in one patient with globozoospermia (round-headed spermatozoa lacking an acrosome), confirming that loss-of-function of GGN can cause this spermatogenic defect in humans.\",\n      \"method\": \"Whole-exome sequencing in a cohort of 69 globozoospermia patients\",\n      \"journal\": \"Human genetics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single patient with a truncating variant identified by WES, no functional validation in this paper\",\n      \"pmids\": [\"33108537\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Knockdown of GGN in colorectal cancer (CRC) cell lines inhibited cellular proliferation and promoted apoptosis, and was associated with reduced phospho-Akt levels, placing GGN upstream of the PI3K/Akt signaling pathway in this context.\",\n      \"method\": \"siRNA knockdown of GGN in CRC cell lines; proliferation and apoptosis assays; Western blotting for p-Akt\",\n      \"journal\": \"Pathology oncology research : POR\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single knockdown experiment with pathway readout but no rescue or mutagenesis to confirm specificity\",\n      \"pmids\": [\"30721393\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GGN (Gametogenetin) is a testis-enriched protein expressed in late pachytene spermatocytes and round spermatids that exists as multiple splice isoforms (GGN1, GGN2, GGN3) with distinct subcellular localizations; GGN1 physically interacts with the DNA repair proteins FANCL, FANCD2, and BRCC36, and loss of GGN in mice causes pre-implantation embryonic lethality and increased unrepaired meiotic DNA double-strand breaks, implicating GGN in the Fanconi Anemia/BRCA DNA repair pathway during spermatogenesis; GGN also interacts with and regulates the localization of POG, a regulator of primordial germ cell proliferation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GGN (Gametogenetin) is a testis-enriched protein expressed in late pachytene spermatocytes and round spermatids that functions in DNA double-strand break repair during male meiosis [#1, #2]. The Ggn locus produces three splice isoforms (GGN1, GGN2, GGN3) with distinct subcellular distributions—GGN1 at the nuclear membrane, GGN2 cytoplasmic, and GGN3 nuclear/nucleolar—and these isoforms regulate the subcellular localization of their interaction partner POG, redirecting it to the perinuclear region or nucleoli [#0]. GGN1, the largest isoform, physically associates with the Fanconi Anemia/BRCA DNA repair proteins FANCL, FANCD2, and BRCC36; complete loss of GGN in mice causes pre-implantation embryonic lethality, while heterozygous spermatocytes accumulate unrepaired meiotic DNA double-strand breaks, placing GGN within the FA/BRCA repair pathway [#2]. A homozygous truncating variant in human GGN was identified in a patient with globozoospermia, linking GGN loss-of-function to this spermatogenic defect [#3].\",\n  \"teleology\": [\n    {\n      \"year\": 2003,\n      \"claim\": \"Established GGN as a POG-interacting protein whose splice isoforms control POG subcellular localization, providing the first molecular handle on GGN function in germ cells.\",\n      \"evidence\": \"Yeast two-hybrid screening with co-expression localization assays in HeLa cells\",\n      \"pmids\": [\"12574169\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Interaction shown in heterologous HeLa system, not in germ cells\", \"Functional consequence of POG relocalization not defined\", \"No structural basis for isoform-specific localization\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Linked GGN expression to the timing of meiosis and to spermatogenesis downstream of POG, framing GGN as a germ-cell-stage-specific factor.\",\n      \"evidence\": \"Expression analysis in mouse testis combined with Pog-deficient mouse meiotic phenotype\",\n      \"pmids\": [\"12574169\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Causal role of GGN itself in meiosis not directly tested here\", \"Mechanism connecting POG to meiotic progression unknown\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Defined a mechanistic role for GGN in meiotic DNA repair by showing GGN1 binds FA/BRCA pathway proteins and that GGN loss disrupts double-strand break repair and is embryonically essential.\",\n      \"evidence\": \"Co-immunoprecipitation from mouse testis, Ggn null mouse generation, and DSB-marker immunostaining in heterozygous pachytene spermatocytes\",\n      \"pmids\": [\"23451117\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Embryonic lethality of nulls prevented direct assessment of meiotic phenotype in homozygotes\", \"Biochemical step within the FA/BRCA pathway performed by GGN not defined\", \"Whether interactions are direct vs. complex-mediated not resolved\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Connected GGN loss-of-function to a human spermatogenic disease phenotype, extending its germ-cell role to clinical infertility.\",\n      \"evidence\": \"Whole-exome sequencing of a globozoospermia cohort identifying a homozygous truncating variant in one patient\",\n      \"pmids\": [\"33108537\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single patient with no functional validation\", \"Causality not established beyond genetic association\", \"Mechanism linking GGN loss to acrosome failure unknown\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Raised a possible context-dependent role for GGN in cell survival signaling outside the germ line, in colorectal cancer cells.\",\n      \"evidence\": \"siRNA knockdown in CRC cell lines with proliferation, apoptosis, and p-Akt readouts\",\n      \"pmids\": [\"30721393\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single knockdown without rescue or mutagenesis to confirm specificity\", \"Direct molecular link between GGN and PI3K/Akt not established\", \"Relationship to germ-cell DNA repair role unclear\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The precise biochemical activity of GGN within the FA/BRCA repair pathway and the functional significance of its isoform-specific localizations remain undefined.\",\n      \"evidence\": null,\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No enzymatic or structural activity assigned to GGN\", \"Mechanism by which GGN promotes DSB repair unresolved\", \"Whether POG and FA/BRCA interactions are part of one functional axis is unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"GO:0005635\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005730\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"POG\", \"FANCL\", \"FANCD2\", \"BRCC36\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":4,"faith_total":4,"faith_pct":100.0}}