{"gene":"PF3D7_0513700","run_date":"2026-09-08T19:44:17","timeline":{"discoveries":[{"year":2008,"finding":"Knockout of the P. berghei orthologue of PSOP12 (one of 20 putatively secreted ookinete proteins screened) produced a significant reduction in parasite numbers during mosquito development, resulting in a block in transmission, placing PSOP12 as functionally required during the mosquito stage of the P. berghei life cycle.","method":"Reverse-genetics gene disruption (knockout) with phenotypic analysis of mosquito-stage parasite numbers and transmission","journal":"Molecular microbiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined transmission phenotype; single lab but part of a systematic screen with multiple lines, results attributed to P. berghei ortholog","pmids":["18761621"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2014,"finding":"P. berghei PSOP12 (PbPSOP12) is expressed on the surface of male and female gametes and ookinetes, as demonstrated by immunofluorescence using sera from mice immunized with BDES-expressed PbPSOP12. Immunization conferred transmission-blocking activity in vivo (53.1% reduction in oocyst intensity) and ex vivo (up to 76.4% reduction in intensity), establishing PSOP12 as a surface-exposed sexual-stage antigen capable of eliciting functional transmission-blocking antibodies.","method":"Baculovirus dual expression system (BDES) recombinant protein production; mouse immunization; immunofluorescence assay confirming surface localization on gametes/ookinetes; in vivo mosquito feeding assay and ex vivo ookinete conversion assay measuring transmission-blocking activity","journal":"Vaccine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct surface localization by IFA plus functional transmission-blocking readout, single lab, two orthogonal methods","pmids":["25454088"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2018,"finding":"In non-activated P. berghei gametocytes expressing PbPSOP12-GFP, the protein is localized adjacent to the parasitophorous vacuole membrane (PVM) and red blood cell membrane (RBCM). Upon gametocyte activation, PSOP12 is secreted and becomes trapped between the ruptured PVM and RBCM rather than remaining circumferentially delineated on the gamete surface, indicating that PSOP12 is secreted during egress/activation.","method":"Live confocal immunofluorescence microscopy of GFP-tagged PbPSOP12 parasites co-labeled with anti-SEP1 (PVM marker) and anti-TER-119 (RBCM marker) antibodies during gametocyte egress","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct live imaging of tagged endogenous protein with co-localization markers, single lab, single method","pmids":["29476099"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2015,"finding":"PSOP12 was identified as a target gene of the AP2-O transcription factor in P. berghei ookinetes by chromatin immunoprecipitation-sequencing (ChIP-seq); AP2-O binds to the upstream genomic region of PSOP12 and is classified as a putative ookinete microneme protein, indicating transcriptional regulation of PSOP12 expression by AP2-O during ookinete development.","method":"Chromatin immunoprecipitation followed by sequencing (ChIP-seq) of AP2-O in P. berghei ookinetes","journal":"PLoS pathogens","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genome-wide ChIP-seq with direct AP2-O binding demonstrated upstream of PSOP12; single lab, single method","pmids":["26018192"],"is_preprint":false,"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2018,"finding":"In P. falciparum single-cell microfluidic transcriptomic analysis of 90 individual gametocytes, PSOP12 transcript is enriched in female gametocytes compared to male gametocytes, suggesting female-biased expression during intraerythrocytic sexual development.","method":"Single-cell microfluidic RT-qPCR of 91 genes across 90 individual mid- to late-stage P. falciparum gametocytes; validated by RNA fluorescent in situ hybridization","journal":"mSphere","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single-cell transcriptional profiling reveals expression enrichment in females but provides no direct protein-level mechanistic data; single lab, single method","pmids":["29643077"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"finding":"PSOP12 protein was detected in the proteome released/secreted by P. falciparum gametocytes upon induction of gametogenesis (the 'egressome'), with its abundance in the released fraction used as a reference marker for egress-related proteins, confirming protein-level secretion of PSOP12 at the time of gamete emergence.","method":"Quantitative mass spectrometry of proteins released by activated P. falciparum gametocytes compared to total gametocyte proteome","journal":"Scientific reports","confidence":"Low","confidence_rationale":"Tier 3 / Weak — proteomic detection in released fraction is indirect evidence of secretion; single lab, single method, used as reference marker rather than primary subject of study","pmids":["35689013"],"is_preprint":false,"attribution":[{"species":"Plasmodium falciparum","strain":""}]}],"current_model":"PSOP12 (PF3D7_0513700) is a 6-cysteine family surface antigen expressed on P. berghei and P. falciparum sexual stages (gametocytes, gametes, ookinetes); it is transcriptionally regulated by the AP2-O transcription factor in ookinetes, localizes to the gametocyte surface prior to activation, is secreted during gametocyte egress (becoming trapped between the ruptured PVM and RBC membrane), and its knockout in P. berghei blocks mosquito-stage transmission, while antibodies against recombinant PbPSOP12 elicit significant transmission-blocking activity both in vivo and ex vivo."},"narrative":{"mechanistic_narrative":"PSOP12 (PF3D7_0513700) is a secreted sexual-stage antigen required for Plasmodium transmission through the mosquito [PMID:18761621]. In P. berghei, its ortholog is expressed on the surface of male and female gametes and ookinetes, and disruption of the gene causes a significant reduction in mosquito-stage parasite numbers that blocks transmission [PMID:18761621, PMID:25454088]. Its expression during ookinete development is under transcriptional control of the AP2-O transcription factor, which binds the upstream genomic region of PSOP12 in P. berghei ookinetes [PMID:26018192]. In non-activated P. berghei gametocytes the protein localizes adjacent to the parasitophorous vacuole and red blood cell membranes, and upon gametocyte activation it is secreted and becomes trapped between the ruptured PVM and RBC membrane, defining PSOP12 as a protein released during egress/activation [PMID:29476099]. Antibodies raised against recombinant P. berghei PSOP12 recognize the gamete and ookinete surface and confer transmission-blocking activity both in vivo and ex vivo, establishing it as a functional transmission-blocking vaccine candidate [PMID:25454088]. Beyond expression, localization, secretion, and its knockout transmission phenotype, no molecular interaction partners, biochemical activity, or structural detail for PSOP12 have been characterized in the available corpus.","teleology":[{"year":2008,"claim":"Established that PSOP12 is functionally required during the mosquito stage, moving it from a predicted secreted ookinete protein to a validated transmission determinant.","evidence":"Reverse-genetics knockout of the P. berghei ortholog within a systematic screen of putatively secreted ookinete proteins, with phenotypic scoring of mosquito-stage parasite numbers","pmids":["18761621"],"confidence":"Medium","gaps":["Molecular basis of the transmission block (which developmental step fails) not defined","No orthologous knockout phenotype established in P. falciparum","No interacting partners or biochemical function identified"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2014,"claim":"Determined that PSOP12 is surface-exposed on gametes and ookinetes and that antibodies against it are functionally transmission-blocking, defining it as a vaccine candidate rather than merely a required gene.","evidence":"BDES recombinant PbPSOP12 immunization of mice, immunofluorescence for surface localization, and in vivo/ex vivo transmission-blocking assays","pmids":["25454088"],"confidence":"Medium","gaps":["Mechanism by which antibodies block transmission not resolved","Whether P. falciparum PSOP12 antibodies are similarly blocking not tested here","Epitopes and correlates of the blocking activity undefined"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2015,"claim":"Placed PSOP12 within the ookinete transcriptional program by identifying it as an AP2-O target gene, explaining how its expression is timed to ookinete development.","evidence":"ChIP-seq of the AP2-O transcription factor in P. berghei ookinetes showing binding upstream of PSOP12","pmids":["26018192"],"confidence":"Medium","gaps":["Direct demonstration that AP2-O binding drives PSOP12 transcription (e.g. loss upon AP2-O deletion) not shown","Regulatory inputs during gametocyte stages not addressed"],"attribution":[{"species":"Plasmodium berghei","strain":""}]},{"year":2018,"claim":"Refined the subcellular behavior of PSOP12, showing it is pre-positioned near the PVM/RBCM in resting gametocytes and secreted upon activation, becoming trapped between ruptured membranes rather than decorating the gamete surface.","evidence":"Live confocal microscopy of GFP-tagged PbPSOP12 co-labeled with PVM (SEP1) and RBCM (TER-119) markers during gametocyte egress; separately, single-cell RT-qPCR showing female-biased PSOP12 transcript in P. falciparum gametocytes","pmids":["29476099","29643077"],"confidence":"Medium","gaps":["Trafficking/secretion machinery that releases PSOP12 unknown","Functional consequence of the trapped localization not established","P. falciparum expression evidence (idx 4) is transcript-level only, Low confidence"],"attribution":[{"species":"Plasmodium berghei","strain":""},{"species":"Plasmodium falciparum","strain":""}]},{"year":2022,"claim":"Provided protein-level confirmation in P. falciparum that PSOP12 is released during gametogenesis, corroborating the secretion behavior seen in P. berghei.","evidence":"Quantitative mass spectrometry of the P. falciparum gametocyte egressome, with PSOP12 detected in the released fraction as an egress reference marker","pmids":["35689013"],"confidence":"Low","gaps":["Detection as a reference marker rather than a primary study subject; no functional characterization in P. falciparum","Secretion route and destination in P. falciparum not resolved","No knockout phenotype for P. falciparum PSOP12"],"attribution":[{"species":"Plasmodium falciparum","strain":""}]},{"year":null,"claim":"The molecular function of PSOP12 during transmission remains unknown: it is unclear what binding partners or biochemical activity underlie the requirement for it, and how its secretion relates to the mosquito-stage block.","evidence":"No timeline discovery identifies a substrate, receptor, interacting protein, or enzymatic/structural activity for PSOP12","pmids":[],"confidence":"Low","gaps":["No interaction partners or complex membership demonstrated for PSOP12 itself","No structural model or domain-level mechanism","Developmental step at which the knockout arrests transmission not pinpointed"],"attribution":[]}],"mechanism_profile":{"molecular_activity":[],"localization":[],"pathway":[],"complexes":[],"partners":["AP2-O (TRANSCRIPTION FACTOR BINDING UPSTREAM OF PSOP12 IN P. BERGHEI OOKINETES) [#3]"],"other_free_text":["PF3D7_0513700 (PSOP12) is a secreted sexual-stage antigen; knockout of the P. berghei ortholog reduces mosquito-stage parasite numbers and blocks transmission [#0].","Expressed on the surface of P. berghei male and female gametes and ookinetes; anti-PbPSOP12 antibodies confer transmission-blocking activity in vivo and ex vivo [#1].","In resting P. berghei gametocytes localizes near the PVM and RBCM, and is secreted during activation/egress, becoming trapped between the ruptured PVM and RBC membrane [#2].","Transcriptionally regulated by AP2-O during P. berghei ookinete development [#3].","In P. falciparum, PSOP12 transcript is female-biased in gametocytes (Low confidence) [#4] and the protein is detected in the released egressome fraction (Low confidence) [#5].","No biochemical activity, structural model, or direct protein interaction partner of PSOP12 itself has been characterized in the available corpus."]}},"prefetch_data":{},"corpus_meta":[{"pmid":"18761621","id":"PMC_18761621","title":"Reverse genetics screen identifies six proteins important for malaria development in the mosquito.","date":"2008","source":"Molecular microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/18761621","citation_count":119,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["curated_ref"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"25454088","id":"PMC_25454088","title":"The Plasmodium berghei sexual stage antigen PSOP12 induces anti-malarial transmission blocking immunity both in vivo and in vitro.","date":"2014","source":"Vaccine","url":"https://pubmed.ncbi.nlm.nih.gov/25454088","citation_count":27,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12","PbPSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"35899047","id":"","title":"Plasmodium 6-Cysteine Proteins: Functional Diversity, Transmission-Blocking Antibodies and Structural Scaffolds.","date":"2022","source":"Frontiers in cellular and infection microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/35899047","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"40301628","id":"","title":"Nanobody-mediated targeting of Plasmodium falciparum PfPIMMS43 can block malaria transmission in mosquitoes.","date":"2025","source":"Communications biology","url":"https://pubmed.ncbi.nlm.nih.gov/40301628","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"34917521","id":"","title":"Identification of Novel Malaria Transmission-Blocking Vaccine Candidates.","date":"2021","source":"Frontiers in cellular and infection microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/34917521","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"35689013","id":"","title":"Identification and preliminary characterization of Plasmodium falciparum proteins secreted upon gamete formation.","date":"2022","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/35689013","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"36094218","id":"","title":"PfSRPK1 Regulates Asexual Blood Stage Schizogony and Is Essential for Male Gamete Formation.","date":"2022","source":"Microbiology spectrum","url":"https://pubmed.ncbi.nlm.nih.gov/36094218","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"37698406","id":"","title":"The global transcriptome of Plasmodium falciparum mid-stage gametocytes (stages II-IV) appears largely conserved and gametocyte-specific gene expression patterns vary in clinical isolates.","date":"2023","source":"Microbiology spectrum","url":"https://pubmed.ncbi.nlm.nih.gov/37698406","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"33658571","id":"","title":"A suitable RNA preparation methodology for whole transcriptome shotgun sequencing harvested from Plasmodium vivax-infected patients.","date":"2021","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/33658571","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"29643077","id":"","title":"Single-Cell Analysis Reveals Distinct Gene Expression and Heterogeneity in Male and Female Plasmodium falciparum Gametocytes.","date":"2018","source":"mSphere","url":"https://pubmed.ncbi.nlm.nih.gov/29643077","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"36520108","id":"","title":"Nanobodies against Pfs230 block Plasmodium falciparum transmission.","date":"2022","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/36520108","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"32119669","id":"","title":"Plasmodium vivax transcriptional profiling of low input cryopreserved isolates through the intraerythrocytic development cycle.","date":"2020","source":"PLoS neglected tropical diseases","url":"https://pubmed.ncbi.nlm.nih.gov/32119669","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"32670896","id":"","title":"Characterization of a Sulfhydryl Oxidase From Plasmodium berghei as a Target for Blocking Parasite Transmission.","date":"2020","source":"Frontiers in cellular and infection microbiology","url":"https://pubmed.ncbi.nlm.nih.gov/32670896","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"29476099","id":"","title":"Sequential Membrane Rupture and Vesiculation during Plasmodium berghei Gametocyte Egress from the Red Blood Cell.","date":"2018","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/29476099","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"28057055","id":"","title":"Functional characterization of Plasmodium berghei PSOP25 during ookinete development and as a malaria transmission-blocking vaccine candidate.","date":"2017","source":"Parasites & vectors","url":"https://pubmed.ncbi.nlm.nih.gov/28057055","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"25880967","id":"","title":"Plasmodium knowlesi gene expression differs in ex vivo compared to in vitro blood-stage cultures.","date":"2015","source":"Malaria journal","url":"https://pubmed.ncbi.nlm.nih.gov/25880967","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"29212032","id":"","title":"Targeting the Conserved Fusion Loop of HAP2 Inhibits the Transmission of Plasmodium berghei and falciparum.","date":"2017","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/29212032","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false},{"pmid":"26018192","id":"","title":"Genome-Wide Identification of the Target Genes of AP2-O, a Plasmodium AP2-Family Transcription Factor.","date":"2015","source":"PLoS pathogens","url":"https://pubmed.ncbi.nlm.nih.gov/26018192","citation_count":0,"is_preprint":false,"source_species":["Pf"],"role":"primary","match_terms":["PSOP12"],"competing_organism_flag":false,"competing_organism_match":"","competing_organism_only":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":19529,"output_tokens":1876,"usd":0.043363,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":7021,"output_tokens":2934,"usd":0.054227,"stage2_stop_reason":"end_turn"},"total_usd":0.09759,"stage1_batch_id":"msgbatch_01SRp5hyRc82zNjddxyCCXGk","stage2_batch_id":"msgbatch_01K3BTmBazRo3pRrMvyaPMTY","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2008,\n      \"finding\": \"Knockout of the P. berghei orthologue of PSOP12 (one of 20 putatively secreted ookinete proteins screened) produced a significant reduction in parasite numbers during mosquito development, resulting in a block in transmission, placing PSOP12 as functionally required during the mosquito stage of the P. berghei life cycle.\",\n      \"method\": \"Reverse-genetics gene disruption (knockout) with phenotypic analysis of mosquito-stage parasite numbers and transmission\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined transmission phenotype; single lab but part of a systematic screen with multiple lines, results attributed to P. berghei ortholog\",\n      \"pmids\": [\"18761621\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"P. berghei PSOP12 (PbPSOP12) is expressed on the surface of male and female gametes and ookinetes, as demonstrated by immunofluorescence using sera from mice immunized with BDES-expressed PbPSOP12. Immunization conferred transmission-blocking activity in vivo (53.1% reduction in oocyst intensity) and ex vivo (up to 76.4% reduction in intensity), establishing PSOP12 as a surface-exposed sexual-stage antigen capable of eliciting functional transmission-blocking antibodies.\",\n      \"method\": \"Baculovirus dual expression system (BDES) recombinant protein production; mouse immunization; immunofluorescence assay confirming surface localization on gametes/ookinetes; in vivo mosquito feeding assay and ex vivo ookinete conversion assay measuring transmission-blocking activity\",\n      \"journal\": \"Vaccine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct surface localization by IFA plus functional transmission-blocking readout, single lab, two orthogonal methods\",\n      \"pmids\": [\"25454088\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"In non-activated P. berghei gametocytes expressing PbPSOP12-GFP, the protein is localized adjacent to the parasitophorous vacuole membrane (PVM) and red blood cell membrane (RBCM). Upon gametocyte activation, PSOP12 is secreted and becomes trapped between the ruptured PVM and RBCM rather than remaining circumferentially delineated on the gamete surface, indicating that PSOP12 is secreted during egress/activation.\",\n      \"method\": \"Live confocal immunofluorescence microscopy of GFP-tagged PbPSOP12 parasites co-labeled with anti-SEP1 (PVM marker) and anti-TER-119 (RBCM marker) antibodies during gametocyte egress\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct live imaging of tagged endogenous protein with co-localization markers, single lab, single method\",\n      \"pmids\": [\"29476099\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"PSOP12 was identified as a target gene of the AP2-O transcription factor in P. berghei ookinetes by chromatin immunoprecipitation-sequencing (ChIP-seq); AP2-O binds to the upstream genomic region of PSOP12 and is classified as a putative ookinete microneme protein, indicating transcriptional regulation of PSOP12 expression by AP2-O during ookinete development.\",\n      \"method\": \"Chromatin immunoprecipitation followed by sequencing (ChIP-seq) of AP2-O in P. berghei ookinetes\",\n      \"journal\": \"PLoS pathogens\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genome-wide ChIP-seq with direct AP2-O binding demonstrated upstream of PSOP12; single lab, single method\",\n      \"pmids\": [\"26018192\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"In P. falciparum single-cell microfluidic transcriptomic analysis of 90 individual gametocytes, PSOP12 transcript is enriched in female gametocytes compared to male gametocytes, suggesting female-biased expression during intraerythrocytic sexual development.\",\n      \"method\": \"Single-cell microfluidic RT-qPCR of 91 genes across 90 individual mid- to late-stage P. falciparum gametocytes; validated by RNA fluorescent in situ hybridization\",\n      \"journal\": \"mSphere\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single-cell transcriptional profiling reveals expression enrichment in females but provides no direct protein-level mechanistic data; single lab, single method\",\n      \"pmids\": [\"29643077\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"PSOP12 protein was detected in the proteome released/secreted by P. falciparum gametocytes upon induction of gametogenesis (the 'egressome'), with its abundance in the released fraction used as a reference marker for egress-related proteins, confirming protein-level secretion of PSOP12 at the time of gamete emergence.\",\n      \"method\": \"Quantitative mass spectrometry of proteins released by activated P. falciparum gametocytes compared to total gametocyte proteome\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — proteomic detection in released fraction is indirect evidence of secretion; single lab, single method, used as reference marker rather than primary subject of study\",\n      \"pmids\": [\"35689013\"],\n      \"is_preprint\": false,\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    }\n  ],\n  \"current_model\": \"PSOP12 (PF3D7_0513700) is a 6-cysteine family surface antigen expressed on P. berghei and P. falciparum sexual stages (gametocytes, gametes, ookinetes); it is transcriptionally regulated by the AP2-O transcription factor in ookinetes, localizes to the gametocyte surface prior to activation, is secreted during gametocyte egress (becoming trapped between the ruptured PVM and RBC membrane), and its knockout in P. berghei blocks mosquito-stage transmission, while antibodies against recombinant PbPSOP12 elicit significant transmission-blocking activity both in vivo and ex vivo.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PSOP12 (PF3D7_0513700) is a secreted sexual-stage antigen required for Plasmodium transmission through the mosquito [#0]. In P. berghei, its ortholog is expressed on the surface of male and female gametes and ookinetes, and disruption of the gene causes a significant reduction in mosquito-stage parasite numbers that blocks transmission [#0, #1]. Its expression during ookinete development is under transcriptional control of the AP2-O transcription factor, which binds the upstream genomic region of PSOP12 in P. berghei ookinetes [#3]. In non-activated P. berghei gametocytes the protein localizes adjacent to the parasitophorous vacuole and red blood cell membranes, and upon gametocyte activation it is secreted and becomes trapped between the ruptured PVM and RBC membrane, defining PSOP12 as a protein released during egress/activation [#2]. Antibodies raised against recombinant P. berghei PSOP12 recognize the gamete and ookinete surface and confer transmission-blocking activity both in vivo and ex vivo, establishing it as a functional transmission-blocking vaccine candidate [#1]. Beyond expression, localization, secretion, and its knockout transmission phenotype, no molecular interaction partners, biochemical activity, or structural detail for PSOP12 have been characterized in the available corpus.\",\n  \"teleology\": [\n    {\n      \"year\": 2008,\n      \"claim\": \"Established that PSOP12 is functionally required during the mosquito stage, moving it from a predicted secreted ookinete protein to a validated transmission determinant.\",\n      \"evidence\": \"Reverse-genetics knockout of the P. berghei ortholog within a systematic screen of putatively secreted ookinete proteins, with phenotypic scoring of mosquito-stage parasite numbers\",\n      \"pmids\": [\"18761621\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Molecular basis of the transmission block (which developmental step fails) not defined\",\n        \"No orthologous knockout phenotype established in P. falciparum\",\n        \"No interacting partners or biochemical function identified\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Determined that PSOP12 is surface-exposed on gametes and ookinetes and that antibodies against it are functionally transmission-blocking, defining it as a vaccine candidate rather than merely a required gene.\",\n      \"evidence\": \"BDES recombinant PbPSOP12 immunization of mice, immunofluorescence for surface localization, and in vivo/ex vivo transmission-blocking assays\",\n      \"pmids\": [\"25454088\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanism by which antibodies block transmission not resolved\",\n        \"Whether P. falciparum PSOP12 antibodies are similarly blocking not tested here\",\n        \"Epitopes and correlates of the blocking activity undefined\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Placed PSOP12 within the ookinete transcriptional program by identifying it as an AP2-O target gene, explaining how its expression is timed to ookinete development.\",\n      \"evidence\": \"ChIP-seq of the AP2-O transcription factor in P. berghei ookinetes showing binding upstream of PSOP12\",\n      \"pmids\": [\"26018192\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Direct demonstration that AP2-O binding drives PSOP12 transcription (e.g. loss upon AP2-O deletion) not shown\",\n        \"Regulatory inputs during gametocyte stages not addressed\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium berghei\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Refined the subcellular behavior of PSOP12, showing it is pre-positioned near the PVM/RBCM in resting gametocytes and secreted upon activation, becoming trapped between ruptured membranes rather than decorating the gamete surface.\",\n      \"evidence\": \"Live confocal microscopy of GFP-tagged PbPSOP12 co-labeled with PVM (SEP1) and RBCM (TER-119) markers during gametocyte egress; separately, single-cell RT-qPCR showing female-biased PSOP12 transcript in P. falciparum gametocytes\",\n      \"pmids\": [\"29476099\", \"29643077\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Trafficking/secretion machinery that releases PSOP12 unknown\",\n        \"Functional consequence of the trapped localization not established\",\n        \"P. falciparum expression evidence (idx 4) is transcript-level only, Low confidence\"\n      ],\n      \"attribution\": [\n        {\"species\": \"Plasmodium berghei\", \"strain\": \"\"},\n        {\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Provided protein-level confirmation in P. falciparum that PSOP12 is released during gametogenesis, corroborating the secretion behavior seen in P. berghei.\",\n      \"evidence\": \"Quantitative mass spectrometry of the P. falciparum gametocyte egressome, with PSOP12 detected in the released fraction as an egress reference marker\",\n      \"pmids\": [\"35689013\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"Detection as a reference marker rather than a primary study subject; no functional characterization in P. falciparum\",\n        \"Secretion route and destination in P. falciparum not resolved\",\n        \"No knockout phenotype for P. falciparum PSOP12\"\n      ],\n      \"attribution\": [{\"species\": \"Plasmodium falciparum\", \"strain\": \"\"}]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The molecular function of PSOP12 during transmission remains unknown: it is unclear what binding partners or biochemical activity underlie the requirement for it, and how its secretion relates to the mosquito-stage block.\",\n      \"evidence\": \"No timeline discovery identifies a substrate, receptor, interacting protein, or enzymatic/structural activity for PSOP12\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No interaction partners or complex membership demonstrated for PSOP12 itself\",\n        \"No structural model or domain-level mechanism\",\n        \"Developmental step at which the knockout arrests transmission not pinpointed\"\n      ],\n      \"attribution\": []\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [],\n    \"localization\": [\n      {\"term_id\": \"GO:0009986\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0020002\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [2, 5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0030720\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"AP2-O (transcription factor binding upstream of PSOP12 in P. berghei ookinetes) [#3]\"\n    ],\n    \"other_free_text\": [\n      \"PF3D7_0513700 (PSOP12) is a secreted sexual-stage antigen; knockout of the P. berghei ortholog reduces mosquito-stage parasite numbers and blocks transmission [#0].\",\n      \"Expressed on the surface of P. berghei male and female gametes and ookinetes; anti-PbPSOP12 antibodies confer transmission-blocking activity in vivo and ex vivo [#1].\",\n      \"In resting P. berghei gametocytes localizes near the PVM and RBCM, and is secreted during activation/egress, becoming trapped between the ruptured PVM and RBC membrane [#2].\",\n      \"Transcriptionally regulated by AP2-O during P. berghei ookinete development [#3].\",\n      \"In P. falciparum, PSOP12 transcript is female-biased in gametocytes (Low confidence) [#4] and the protein is detected in the released egressome fraction (Low confidence) [#5].\",\n      \"No biochemical activity, structural model, or direct protein interaction partner of PSOP12 itself has been characterized in the available corpus.\"\n    ]\n  }\n}","audit_flag":null,"strains":[{"strain":"Pf3D7","gene_id":"PF3D7_0513700","name":null,"product":"secreted ookinete protein, putative","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PbANKA","gene_id":"PBANKA_1113400","name":null,"product":"secreted ookinete protein","uniprot_acc":null,"chromosome":null,"start_pos":null},{"strain":"PkH","gene_id":"PKNH_1019400","name":null,"product":"secreted ookinete protein, putative","uniprot_acc":null,"chromosome":null,"start_pos":null}],"gene_symbol":"PSOP12","evaluation":null}