{"gene":"TG_308970","gene_symbol":"GRA12D","run_date":"2026-09-08T15:15:13","timeline":{"discoveries":[{"year":2021,"finding":"GRA12D is expressed in asexual stage tachyzoites and bradyzoites, colocalizes with dense granules in extracellular tachyzoites, with GRA2 and the intravacuolar network in the tachyzoite-stage parasitophorous vacuole, and is secreted by bradyzoites and incorporated into the developing cyst wall and cyst matrix.","method":"Fluorescence microscopy/colocalization, gene expression analysis, and stage-specific localization studies","journal":"mSphere","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct localization by fluorescence microscopy with colocalization controls, single lab, multiple stage comparisons","pmids":["33883265"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2021,"finding":"Deletion of GRA12D (Δgra12D) caused no major defects in acute virulence but resulted in reduced in vitro cyst reactivation efficiency, indicating GRA12D plays a role in chronic stage cyst reactivation rather than acute infection.","method":"Gene knockout (Δgra12D), mouse infection model for acute virulence, in vitro cyst reactivation assay","journal":"mSphere","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined cellular phenotype (reactivation assay and in vivo virulence), single lab","pmids":["33883265"],"is_preprint":false,"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"current_model":"GRA12D is a dense granule protein expressed in tachyzoites and bradyzoites that localizes to the intravacuolar network and is incorporated into the cyst wall and cyst matrix; it is dispensable for acute virulence but contributes to efficient reactivation of chronic-stage cysts."},"narrative":{"mechanistic_narrative":"GRA12D is a Toxoplasma gondii dense granule protein expressed across both the acute (tachyzoite) and chronic (bradyzoite) asexual stages that contributes to chronic-stage cyst biology [PMID:33883265]. In tachyzoites it colocalizes with dense granules in extracellular parasites and with GRA2 and the intravacuolar network within the parasitophorous vacuole, and in bradyzoites it is secreted and incorporated into the developing cyst wall and cyst matrix [PMID:33883265]. Functionally, GRA12D is dispensable for acute virulence but is required for efficient cyst reactivation: deletion reduces in vitro reactivation efficiency, placing GRA12D in the chronic-to-recrudescent transition rather than acute infection [PMID:33883265]. Beyond this localization and knockout phenotype, no molecular activity, binding partner, or biochemical mechanism for GRA12D has been characterized in the available corpus.","teleology":[{"year":2021,"claim":"Establishing where and when GRA12D acts was the first step: it defined GRA12D as a stage-spanning dense granule protein that transitions from the tachyzoite intravacuolar network to the bradyzoite cyst wall and matrix.","evidence":"Fluorescence microscopy/colocalization with dense granules, GRA2, and the intravacuolar network, plus stage-specific expression and secretion analysis in Toxoplasma gondii","pmids":["33883265"],"confidence":"Medium","gaps":["No molecular partners or binding interactions within the intravacuolar network or cyst wall identified","Mechanism of secretion and incorporation into the cyst matrix not defined","No biochemical or enzymatic activity assigned"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":2021,"claim":"Genetic ablation tested whether GRA12D is functionally required, revealing a stage-restricted role: it is dispensable for acute virulence but needed for efficient chronic cyst reactivation.","evidence":"Gene knockout (Δgra12D) assessed by mouse acute virulence infection and in vitro cyst reactivation assay in Toxoplasma gondii","pmids":["33883265"],"confidence":"Medium","gaps":["Molecular mechanism linking GRA12D to reactivation efficiency unknown","Single lab, in vitro reactivation readout without in vivo reactivation confirmation","Whether the cyst-wall/matrix localization mediates the reactivation phenotype is untested"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]},{"year":null,"claim":"The molecular function of GRA12D — its binding partners, biochemical activity, and the mechanism by which its cyst-wall localization drives reactivation — remains undefined.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No interactome or structural data","No defined molecular activity","Causal link between cyst-matrix incorporation and reactivation not established"],"attribution":[{"species":"Toxoplasma gondii","strain":""}]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["GRA2 (COLOCALIZATION IN THE INTRAVACUOLAR NETWORK)"],"other_free_text":["Expressed in both tachyzoites and bradyzoites; secreted by bradyzoites into the developing cyst wall [#0]","Dispensable for acute virulence in the mouse infection model; required for efficient in vitro cyst reactivation [#1]"]},"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},{"pmid":"36210525","id":"PMC_36210525","title":"Importance of aspartyl protease 5 in the establishment of the intracellular niche during acute and chronic infection of Toxoplasma gondii.","date":"2022","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/36210525","citation_count":6,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":3738,"output_tokens":565,"usd":0.009845,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":5260,"output_tokens":1672,"usd":0.03405,"stage2_stop_reason":"end_turn"},"total_usd":0.043895,"stage1_batch_id":"msgbatch_01S6GjoYQm8LTPUsdhASdqag","stage2_batch_id":"msgbatch_01VX63RTMdBJqsG6gQMqoCjz","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2021,\n      \"finding\": \"GRA12D is expressed in asexual stage tachyzoites and bradyzoites, colocalizes with dense granules in extracellular tachyzoites, with GRA2 and the intravacuolar network in the tachyzoite-stage parasitophorous vacuole, and is secreted by bradyzoites and incorporated into the developing cyst wall and cyst matrix.\",\n      \"method\": \"Fluorescence microscopy/colocalization, gene expression analysis, and stage-specific localization studies\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct localization by fluorescence microscopy with colocalization controls, single lab, multiple stage comparisons\",\n      \"pmids\": [\"33883265\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Deletion of GRA12D (Δgra12D) caused no major defects in acute virulence but resulted in reduced in vitro cyst reactivation efficiency, indicating GRA12D plays a role in chronic stage cyst reactivation rather than acute infection.\",\n      \"method\": \"Gene knockout (Δgra12D), mouse infection model for acute virulence, in vitro cyst reactivation assay\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined cellular phenotype (reactivation assay and in vivo virulence), single lab\",\n      \"pmids\": [\"33883265\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"GRA12D is a dense granule protein expressed in tachyzoites and bradyzoites that localizes to the intravacuolar network and is incorporated into the cyst wall and cyst matrix; it is dispensable for acute virulence but contributes to efficient reactivation of chronic-stage cysts.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GRA12D is a Toxoplasma gondii dense granule protein expressed across both the acute (tachyzoite) and chronic (bradyzoite) asexual stages that contributes to chronic-stage cyst biology [#0, #1]. In tachyzoites it colocalizes with dense granules in extracellular parasites and with GRA2 and the intravacuolar network within the parasitophorous vacuole, and in bradyzoites it is secreted and incorporated into the developing cyst wall and cyst matrix [#0]. Functionally, GRA12D is dispensable for acute virulence but is required for efficient cyst reactivation: deletion reduces in vitro reactivation efficiency, placing GRA12D in the chronic-to-recrudescent transition rather than acute infection [#1]. Beyond this localization and knockout phenotype, no molecular activity, binding partner, or biochemical mechanism for GRA12D has been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2021,\n      \"claim\": \"Establishing where and when GRA12D acts was the first step: it defined GRA12D as a stage-spanning dense granule protein that transitions from the tachyzoite intravacuolar network to the bradyzoite cyst wall and matrix.\",\n      \"evidence\": \"Fluorescence microscopy/colocalization with dense granules, GRA2, and the intravacuolar network, plus stage-specific expression and secretion analysis in Toxoplasma gondii\",\n      \"pmids\": [\"33883265\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No molecular partners or binding interactions within the intravacuolar network or cyst wall identified\",\n        \"Mechanism of secretion and incorporation into the cyst matrix not defined\",\n        \"No biochemical or enzymatic activity assigned\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Genetic ablation tested whether GRA12D is functionally required, revealing a stage-restricted role: it is dispensable for acute virulence but needed for efficient chronic cyst reactivation.\",\n      \"evidence\": \"Gene knockout (\\u0394gra12D) assessed by mouse acute virulence infection and in vitro cyst reactivation assay in Toxoplasma gondii\",\n      \"pmids\": [\"33883265\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Molecular mechanism linking GRA12D to reactivation efficiency unknown\",\n        \"Single lab, in vitro reactivation readout without in vivo reactivation confirmation\",\n        \"Whether the cyst-wall/matrix localization mediates the reactivation phenotype is untested\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular function of GRA12D — its binding partners, biochemical activity, and the mechanism by which its cyst-wall localization drives reactivation — remains undefined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No interactome or structural data\",\n        \"No defined molecular activity\",\n        \"Causal link between cyst-matrix incorporation and reactivation not established\"\n      ],\n      \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"dense granule\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"intravacuolar network / parasitophorous vacuole\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]},\n      {\"term_id\": \"cyst wall and cyst matrix\", \"supporting_discovery_ids\": [0], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"chronic-stage cyst reactivation\", \"supporting_discovery_ids\": [1], \"attribution\": [{\"species\": \"Toxoplasma gondii\", \"strain\": \"\"}]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"GRA2 (colocalization in the intravacuolar network)\"],\n    \"other_free_text\": [\n      \"Expressed in both tachyzoites and bradyzoites; secreted by bradyzoites into the developing cyst wall [#0]\",\n      \"Dispensable for acute virulence in the mouse infection model; required for efficient in vitro cyst reactivation [#1]\"\n    ]\n  },\n  \"strain_conflicts\": []\n}","audit_flag":null,"strains":[{"strain":"ME49","gene_id":"TGME49_308970","name":"GRA12D","product":"dense granule protein GRA12D","uniprot_acc":"A0A125YT37","chromosome":"TGME49_chrXI","start_pos":409902},{"strain":"GT1","gene_id":"TGGT1_308970","name":null,"product":"hypothetical protein","uniprot_acc":null,"chromosome":"TGGT1_chrXI","start_pos":373848},{"strain":"RH88","gene_id":"TGRH88_048660","name":null,"product":"unspecified product","uniprot_acc":null,"chromosome":"CM023092","start_pos":450113},{"strain":"VEG","gene_id":"TGVEG_308970","name":null,"product":"hypothetical protein","uniprot_acc":"B6K9Y8","chromosome":"TGVEG_chrXI","start_pos":418256}]}