{"gene":"TG_220890","gene_symbol":"GRA12A","run_date":"2026-09-08T11:06:37","timeline":{"discoveries":[{"year":2021,"finding":"GRA12A is a dense granule protein secreted by bradyzoites that localizes to the cyst wall and cyst matrix, colocalizing with GRA2 and the intravacuolar network (IVN) in both tachyzoite and bradyzoite stages, placing it within the IVN membrane system.","method":"Fluorescence microscopy / colocalization with GRA2 and IVN markers in tachyzoites and bradyzoites","journal":"mSphere","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct localization experiments with colocalization controls in multiple life stages, single lab","pmids":["33883265"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2021,"finding":"Deletion of GRA12A (Δgra12A) reduces chronic-stage cyst burdens in mice and delays cyst reactivation in vitro, establishing a role for GRA12A in cyst formation, maintenance, and reactivation during chronic infection.","method":"Genetic knockout (Δgra12A), in vivo mouse infection (cyst burden counts), in vitro cyst reactivation assay","journal":"mSphere","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined in vivo and in vitro phenotypic readouts, single lab","pmids":["33883265"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"GRA12A is a dense granule protein that is secreted by bradyzoites and incorporated into the cyst wall and cyst matrix (associating with GRA2 and the intravacuolar network), where it promotes chronic-stage cyst development, persistence, and reactivation, as demonstrated by reduced cyst burdens and delayed reactivation upon its deletion."},"narrative":{"mechanistic_narrative":"GRA12A is a Toxoplasma gondii dense granule protein that supports chronic-stage cyst biology [PMID:33883265]. It is secreted by bradyzoites and localizes to the cyst wall and cyst matrix, colocalizing with GRA2 and the intravacuolar network (IVN), placing it within the IVN membrane system in both tachyzoite and bradyzoite stages [PMID:33883265]. Functionally, deletion of GRA12A reduces chronic-stage cyst burdens in mice and delays cyst reactivation in vitro, establishing a role in cyst formation, maintenance, and reactivation during chronic infection [PMID:33883265]. Beyond its IVN association and these cyst phenotypes, the molecular mechanism by which GRA12A acts has not been characterized in the available corpus.","teleology":[{"year":2021,"claim":"Establishing where GRA12A resides answered whether it is part of the parasite's intravacuolar membrane machinery, situating it alongside known dense granule/IVN components.","evidence":"Fluorescence microscopy and colocalization with GRA2 and IVN markers in tachyzoites and bradyzoites","pmids":["33883265"],"confidence":"Medium","gaps":["Direct binding partners within the IVN are not defined; colocalization does not establish physical interaction","No structural or biochemical basis for IVN membrane association identified"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2021,"claim":"Genetic deletion answered whether GRA12A is functionally required, linking its IVN localization to chronic-stage cyst development, persistence, and reactivation.","evidence":"Δgra12A knockout with in vivo mouse cyst burden counts and in vitro cyst reactivation assay","pmids":["33883265"],"confidence":"Medium","gaps":["The molecular mechanism connecting GRA12A to reduced cyst burden is unknown","Whether the reactivation delay reflects a defect in cyst wall integrity, matrix organization, or bradyzoite viability is unresolved"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The biochemical activity of GRA12A and its direct molecular partners at the IVN and cyst wall remain undefined.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No enzymatic or structural function assigned","No direct physical interaction with GRA2 or other IVN proteins demonstrated","Host-directed effects, if any, are uncharacterized"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["GRA2 (COLOCALIZATION AT IVN AND CYST MATRIX)"],"other_free_text":["Secreted by bradyzoites and incorporated into the cyst wall and cyst matrix","Deletion reduces chronic-stage cyst burdens in mice and delays cyst reactivation in vitro"]},"strain_conflicts":[]},"prefetch_data":{},"corpus_meta":[{"pmid":"33883265","id":"PMC_33883265","title":"A Family of Toxoplasma gondii Genes Related to GRA12 Regulate Cyst Burdens and Cyst Reactivation.","date":"2021","source":"mSphere","url":"https://pubmed.ncbi.nlm.nih.gov/33883265","citation_count":12,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":3274,"output_tokens":561,"usd":0.009118,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5254,"output_tokens":1563,"usd":0.032673,"stage2_stop_reason":"end_turn"},"total_usd":0.041791,"stage1_batch_id":"msgbatch_01WokvBYTB6JLnYrpD4rXnyV","stage2_batch_id":"msgbatch_01M7hsQDvz6AqVC9DLVjQzzc","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2021,\n      \"finding\": \"GRA12A is a dense granule protein secreted by bradyzoites that localizes to the cyst wall and cyst matrix, colocalizing with GRA2 and the intravacuolar network (IVN) in both tachyzoite and bradyzoite stages, placing it within the IVN membrane system.\",\n      \"method\": \"Fluorescence microscopy / colocalization with GRA2 and IVN markers in tachyzoites and bradyzoites\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct localization experiments with colocalization controls in multiple life stages, single lab\",\n      \"pmids\": [\"33883265\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Deletion of GRA12A (Δgra12A) reduces chronic-stage cyst burdens in mice and delays cyst reactivation in vitro, establishing a role for GRA12A in cyst formation, maintenance, and reactivation during chronic infection.\",\n      \"method\": \"Genetic knockout (Δgra12A), in vivo mouse infection (cyst burden counts), in vitro cyst reactivation assay\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined in vivo and in vitro phenotypic readouts, single lab\",\n      \"pmids\": [\"33883265\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"GRA12A is a dense granule protein that is secreted by bradyzoites and incorporated into the cyst wall and cyst matrix (associating with GRA2 and the intravacuolar network), where it promotes chronic-stage cyst development, persistence, and reactivation, as demonstrated by reduced cyst burdens and delayed reactivation upon its deletion.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GRA12A is a Toxoplasma gondii dense granule protein that supports chronic-stage cyst biology [#0, #1]. It is secreted by bradyzoites and localizes to the cyst wall and cyst matrix, colocalizing with GRA2 and the intravacuolar network (IVN), placing it within the IVN membrane system in both tachyzoite and bradyzoite stages [#0]. Functionally, deletion of GRA12A reduces chronic-stage cyst burdens in mice and delays cyst reactivation in vitro, establishing a role in cyst formation, maintenance, and reactivation during chronic infection [#1]. Beyond its IVN association and these cyst phenotypes, the molecular mechanism by which GRA12A acts has not been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2021,\n      \"claim\": \"Establishing where GRA12A resides answered whether it is part of the parasite's intravacuolar membrane machinery, situating it alongside known dense granule/IVN components.\",\n      \"evidence\": \"Fluorescence microscopy and colocalization with GRA2 and IVN markers in tachyzoites and bradyzoites\",\n      \"pmids\": [\n        \"33883265\"\n      ],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Direct binding partners within the IVN are not defined; colocalization does not establish physical interaction\",\n        \"No structural or biochemical basis for IVN membrane association identified\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Toxoplasma gondii\",\n          \"strain\": \"\"\n        }\n      ]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Genetic deletion answered whether GRA12A is functionally required, linking its IVN localization to chronic-stage cyst development, persistence, and reactivation.\",\n      \"evidence\": \"Δgra12A knockout with in vivo mouse cyst burden counts and in vitro cyst reactivation assay\",\n      \"pmids\": [\n        \"33883265\"\n      ],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"The molecular mechanism connecting GRA12A to reduced cyst burden is unknown\",\n        \"Whether the reactivation delay reflects a defect in cyst wall integrity, matrix organization, or bradyzoite viability is unresolved\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Toxoplasma gondii\",\n          \"strain\": \"\"\n        }\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The biochemical activity of GRA12A and its direct molecular partners at the IVN and cyst wall remain undefined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No enzymatic or structural function assigned\",\n        \"No direct physical interaction with GRA2 or other IVN proteins demonstrated\",\n        \"Host-directed effects, if any, are uncharacterized\"\n      ],\n      \"attribution\": [\n        {\n          \"species\": \"Toxoplasma gondii\",\n          \"strain\": \"\"\n        }\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\n        \"term_id\": \"cyst wall\",\n        \"supporting_discovery_ids\": [0],\n        \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n      },\n      {\n        \"term_id\": \"intravacuolar network (IVN)\",\n        \"supporting_discovery_ids\": [0],\n        \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n      },\n      {\n        \"term_id\": \"dense granule\",\n        \"supporting_discovery_ids\": [0],\n        \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n      }\n    ],\n    \"pathway\": [\n      {\n        \"term_id\": \"chronic-stage cyst development and reactivation\",\n        \"supporting_discovery_ids\": [1],\n        \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n      }\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"GRA2 (colocalization at IVN and cyst matrix)\"\n    ],\n    \"other_free_text\": [\n      \"Secreted by bradyzoites and incorporated into the cyst wall and cyst matrix\",\n      \"Deletion reduces chronic-stage cyst burdens in mice and delays cyst reactivation in vitro\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_220890","name":"GRA12A","product":"dense granule protein GRA12A","uniprot_acc":"S8FDY4","chromosome":"TGME49_chrII","start_pos":37902},{"strain":"GT1","gene_id":"TGGT1_220890","name":null,"product":"hypothetical protein","uniprot_acc":null,"chromosome":"TGGT1_chrII","start_pos":23072},{"strain":"RH88","gene_id":"TGRH88_000070","name":null,"product":"unspecified product","uniprot_acc":null,"chromosome":"CM023083","start_pos":178264},{"strain":"VEG","gene_id":"TGVEG_220890","name":null,"product":"putative transmembrane protein","uniprot_acc":"B9Q3R8","chromosome":"TGVEG_chrII","start_pos":37393}]}