Affinage · Plasmodium

AP2-G2

PF3D7_1408200 · AP2 domain transcription factor AP2-G2

Annotated
2026-09-08
73 papers in source corpus 8 papers cited in narrative 9 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

PF3D7_1408200 (AP2-G2) is an AP2-domain transcription factor that acts as a global transcriptional repressor operating within the ApiAP2 regulatory cascade that governs the transition from asexual proliferation to sexual development in Plasmodium (PMID:26417110, PMID:28081440, PMID:33368818). It sits downstream of the master commitment regulator AP2-G: single-cell transcriptomics in P. falciparum show AP2-G2 is upregulated in sexually committed cells (PMID:29094698), and AP2-G directly binds upstream of AP2-G2 in P. berghei (PMID:34119684). Genome-wide ChIP-seq establishes that AP2-G2 binds ~1,500 gene promoters through a five-base cis-acting negative regulatory motif and that most targets encode asexual-proliferation functions, so its loss de-represses the asexual program without preventing sexual commitment (PMID:26417110); in P. falciparum it additionally binds within the gene bodies of ~3,000 genes in correlation with H3K36me3 and HP1 occupancy, and its disruption causes overexpression, but no downregulation, of bound genes, confirming repressor activity (PMID:33368818). Functionally, AP2-G2 is required for gametocyte maturation past stage III, and its disruption arrests sexual parasites before sex-specific morphologies emerge (PMID:26417110, PMID:33368818), with a disproportionate loss of male gametocytes traceable to direct activation of the male development gene PfMDV-1, whose transcription start site AP2-G2 occupies (PMID:33537025). AP2-G2 localizes to the nucleus (PMID:33537025) and physically associates with chromatin remodeling proteins, a MORC protein, and the ApiAP2 factor PF3D7_1139300 (PMID:33368818), and is found in a gametocyte-specific SAGA-like chromatin complex linked to a defined histone code (PMID:35051657), indicating it exerts repression in the context of chromatin-modifying machinery.

Mechanistic history

Synthesis pass · year-by-year structured walk · 8 steps
  1. 2014 Medium

    Establishing whether AP2-G2 contributes to sexual development addressed which ApiAP2 factors act beyond the master commitment switch; deletion showed it modulates gametocytogenesis rather than triggering it.

    Evidence Systematic gene deletion with gametocytogenesis phenotypic readout in P. berghei

    PMID:24572359

    Open questions at the time
    • Did not define molecular activity or direct targets
    • Modulatory role not mechanistically explained
    • Single lab, single method for this gene
  2. 2015 High

    Defining the molecular mode of action distinguished AP2-G2 from activating ApiAP2 factors; ChIP-seq, transcriptomics, and a promoter assay established it as a repressor that silences asexual genes via a five-base cis-negative element.

    Evidence Knockout, ChIP-seq (~1,500 targets), microarray, and promoter assay in P. berghei

    PMID:26417110

    Open questions at the time
    • Mechanism of repression at chromatin not resolved
    • Interaction partners unidentified
    • Stage-arrest point not precisely mapped
  3. 2017 High

    Placing AP2-G2 in a genome-wide ApiAP2 network clarified that its repressive activity spans both asexual and sexual stages, coordinating clusters of co-regulated genes with shared cis elements.

    Evidence Systematic knockout screen and comparative transcriptomics across mutants and developmental stages in P. berghei

    PMID:28081440

    Open questions at the time
    • Direct vs indirect target discrimination limited by transcriptomics
    • No structural or biochemical partner data
  4. 2017 Medium

    Determining the regulatory hierarchy of commitment placed AP2-G2 downstream of AP2-G by showing its upregulation specifically in sexually committed cells.

    Evidence Single-cell RNA-seq of >18,000 transcriptomes using conditional AP2-G knockdown and NF54 wild-type P. falciparum

    PMID:29094698

    Open questions at the time
    • Transcriptomic correlation only, no direct binding shown in this study
    • Functional consequence of upregulation not tested here
  5. 2021 High

    Extending function to P. falciparum defined the maturation arrest point and revealed gene-body binding and chromatin partners, linking repression to specific histone marks and a physical complex.

    Evidence Knockout (stage III arrest), promoter and gene-body ChIP-seq, RNA-seq, Co-IP, and histone modification correlation in P. falciparum

    PMID:33368818

    Open questions at the time
    • Functional role of gene-body binding not experimentally dissected
    • Direct vs bridged nature of Co-IP interactions unresolved
    • How H3K36me3/HP1 context directs binding unknown
  6. 2021 High

    Explaining the sex-ratio phenotype identified a direct activated target, showing AP2-G2 supports male gametocyte production by driving PfMDV-1 transcription.

    Evidence Knockout, RT-qPCR, RNA-seq, ChIP-qPCR at PfMDV-1 TSS, and IFA in P. falciparum

    PMID:33537025

    Open questions at the time
    • Reconciliation of activation of PfMDV-1 with predominantly repressor role not mechanistically explained
    • Whether AP2-G downregulation in KO schizonts is direct or secondary unknown
  7. 2021 Medium

    Localizing AP2-G2 confirmed nuclear residence consistent with a chromatin-acting transcription factor.

    Evidence Indirect immunofluorescence assay in P. falciparum asexual blood stages

    PMID:33537025

    Open questions at the time
    • Single method localization
    • No dynamics across sexual stages reported
  8. 2022 Medium

    Chromatin proteomics tied AP2-G2 to a defined effector complex, indicating it operates within a gametocyte-specific SAGA-like machinery associated with a particular histone code.

    Evidence Quantitative middle-down proteomics and chromatin proteomics in P. falciparum mature gametocytes

    PMID:35051657

    Open questions at the time
    • Complex membership from one method without functional validation
    • Direct contribution of AP2-G2 to the histone code not tested
    • Complex stoichiometry and stage-specificity unresolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • How AP2-G2 mechanistically switches between global repression of asexual genes and direct activation of male-development genes, and how its gene-body binding and chromatin-complex associations execute repression, remains unresolved.
  • No structural basis for the dual repressor/activator behavior
  • Function of gene-body binding vs promoter binding undissected
  • Direct effector role within the SAGA-like/MORC complexes untested

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
AP2-G (MASTER REGULATOR, BINDS UPSTREAM OF AP2-G2) [#3, #5]APIAP2 FACTOR PF3D7_1139300 (CO-IP) [#4]CHROMATIN REMODELING PROTEINS (CO-IP) [#4]MORC PROTEIN (CO-IP) [#4]PFMDV-1 / PF3D7_1216500 (DIRECT TARGET, TSS BINDING) [#6]
Complex memberships
Gametocyte-specific SAGA-like chromatin effector complex associated with H3R17me2K18acK23ac [#8]

Evidence

Reading pass · 9 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2014 AP2-G2 (PBANKA_103430) gene deletion in P. berghei significantly modulates but does not abolish gametocytogenesis, indicating it plays a modulatory role in commitment to gametocyte production and maturation, downstream of AP2-G in a cascade of ApiAP2 proteins. Systematic gene deletion (knockout screen) in Plasmodium berghei with gametocytogenesis phenotypic readout Nature Medium 24572359
2015 AP2-G2 functions as a transcriptional repressor in P. berghei gametocytes. Disruption of AP2-G2 did not prevent commitment to the sexual stage but halted development before sex-specific morphologies appeared. ChIP-seq revealed AP2-G2 targets ~1,500 genes by recognizing a five-base promoter motif; most target genes are required for asexual proliferation. Microarray analysis showed ~70% of up-regulated genes in AP2-G2-depleted parasites were AP2-G2 targets. A promoter assay demonstrated the AP2-G2 binding motif functions as a cis-acting negative regulatory element. Gene disruption/knockout, ChIP-seq, microarray transcriptome analysis, promoter assay with centromere plasmid Proceedings of the National Academy of Sciences of the United States of America High 26417110
2017 AP2-G2 was identified as a repressor active in both asexual and sexual stages of P. berghei. A systematic knockout screen across ApiAP2 genes revealed AP2-G2 as a transcriptional repressor, and comparative transcriptomics across mutants and developmental stages revealed clusters of co-regulated genes with shared cis promoter elements whose expression is controlled negatively by AP2-G2. Systematic knockout screen in Plasmodium berghei, comparative transcriptomics across mutants and developmental stages Cell host & microbe High 28081440
2017 Single-cell RNA-seq of sexually committed AP2-G+ mature schizonts in P. falciparum revealed upregulation of additional AP2 transcription factors (including AP2-G2/PF3D7_1408200) in sexually committed cells, placing AP2-G2 as a downstream target of AP2-G during the commitment cycle. Single-cell RNA sequencing of >18,000 parasite transcriptomes using a conditional AP2-G knockdown line and NF54 wild-type parasites Nature Medium 29094698
2021 In P. falciparum, PfAP2-G2 (PF3D7_1408200) plays a critical role in gametocyte maturation. PfAP2-G2 binds promoters of a wide array of genes across parasite life cycle stages and also binds within gene bodies of ~3,000 genes, which correlates with H3K36me3, other histone modifications, and HP1 occupancy, suggesting gene body binding as an alternative regulatory mechanism. Disruption of pfap2-g2 does not impact asexual development but causes the majority of sexual parasites to arrest at stage III gametocytes. Absence of pfap2-g2 leads to overexpression of 28% of bound genes with no downregulation of bound genes, confirming repressor function. PfAP2-G2 co-immunoprecipitates with chromatin remodeling proteins, a MORC protein, and another ApiAP2 protein (PF3D7_1139300). Gene disruption/knockout, ChIP-seq (promoter and gene body binding), RNA-seq, co-immunoprecipitation, histone modification correlation analysis Molecular microbiology High 33368818
2021 AP2-G2 is identified as a target gene directly bound by AP2-G in P. berghei, placing AP2-G2 downstream in a transcriptional cascade initiated by AP2-G that promotes gametocyte development; AP2-G binding sites exist upstream of AP2-G2 in the genome. ChIP-seq of AP2-G at peak expression, fluorescence microscopy of AP2-G expression timing Parasitology international Medium 34119684
2021 In P. falciparum, PfAP2-G2 (PF3D7_1408200) knockout leads to ~95% decrease in mature gametocyte numbers with a greater impact on male gametocyte production, resulting in a higher female/male ratio. RNA-seq and RT-qPCR showed disruption of PfAP2-G2 causes downregulation of PfMDV-1 (male development gene-1, PF3D7_1216500). ChIP-qPCR demonstrated PfAP2-G2 is enriched at the transcriptional start site of PfMDV-1 in both ring and schizont stages. PfAP2-G (the master regulator) is also downregulated in pfap2-g2 knockout schizonts but not in ring stages. Gene knockout, RT-qPCR, RNA-seq, chromatin immunoprecipitation followed by qPCR (ChIP-qPCR), indirect immunofluorescence assay Frontiers in microbiology High 33537025
2021 Indirect immunofluorescence assay in P. falciparum showed nuclear localization of PfAP2-G2 in asexual blood stages, consistent with its role as a transcription factor. Indirect immunofluorescence assay (IFA) Frontiers in microbiology Medium 33537025
2021 In P. falciparum mature gametocytes, a gametocyte-specific SAGA-like effector complex including PfAP2-G2 was identified by chromatin proteomics and tied to the specific histone code H3R17me2K18acK23ac, suggesting PfAP2-G2 participates in a chromatin regulatory complex associated with this histone modification in mature gametocytes. Quantitative middle-down proteomics for histone codes, chromatin proteomics for complex identification Molecular & cellular proteomics : MCP Medium 35051657

Source papers

Stage 0 corpus · 73 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2014 A transcriptional switch underlies commitment to sexual development in malaria parasites. Nature 397 24572369
2005 Discovery of the principal specific transcription factors of Apicomplexa and their implication for the evolution of the AP2-integrase DNA binding domains. Nucleic acids research 395 16040597
2014 A cascade of DNA-binding proteins for sexual commitment and development in Plasmodium. Nature 326 24572359
2014 Heterochromatin protein 1 secures survival and transmission of malaria parasites. Cell host & microbe 217 25121746
2018 GDV1 induces sexual commitment of malaria parasites by antagonizing HP1-dependent gene silencing. Science (New York, N.Y.) 195 29590075
2008 Specific DNA-binding by apicomplexan AP2 transcription factors. Proceedings of the National Academy of Sciences of the United States of America 193 18541913
2014 A Plasmodium falciparum histone deacetylase regulates antigenic variation and gametocyte conversion. Cell host & microbe 174 25121747
2017 Single-cell RNA sequencing reveals a signature of sexual commitment in malaria parasites. Nature 168 29094698
2009 Identification of a transcription factor in the mosquito-invasive stage of malaria parasites. Molecular microbiology 164 19220746
2017 A Knockout Screen of ApiAP2 Genes Reveals Networks of Interacting Transcriptional Regulators Controlling the Plasmodium Life Cycle. Cell host & microbe 163 28081440
2010 The Apicomplexan AP2 family: integral factors regulating Plasmodium development. Molecular and biochemical parasitology 156 21126543
2018 Chromatin Accessibility-Based Characterization of the Gene Regulatory Network Underlying Plasmodium falciparum Blood-Stage Development. Cell host & microbe 140 29649445
2010 A major role for the Plasmodium falciparum ApiAP2 protein PfSIP2 in chromosome end biology. PLoS pathogens 134 20195509
2009 Transcription factor AP2-Sp and its target genes in malarial sporozoites. Molecular microbiology 129 20025671
2017 Red Blood Cell Invasion by the Malaria Parasite Is Coordinated by the PfAP2-I Transcription Factor. Cell host & microbe 113 28618269
2020 Dissecting the role of PfAP2-G in malaria gametocytogenesis. Nature communications 108 32198457
2018 Regulation of Sexual Commitment and Gametocytogenesis in Malaria Parasites. Annual review of microbiology 91 29975590
2018 Revisiting the initial steps of sexual development in the malaria parasite Plasmodium falciparum. Nature microbiology 91 30478286
2012 Identification of an AP2-family protein that is critical for malaria liver stage development. PloS one 88 23144823
2015 Global transcriptional repression: An initial and essential step for Plasmodium sexual development. Proceedings of the National Academy of Sciences of the United States of America 84 26417110
2012 A tetracycline-repressible transactivator system to study essential genes in malaria parasites. Cell host & microbe 76 23245327
2017 Epigenetic regulation of Plasmodium falciparum clonally variant gene expression during development in Anopheles gambiae. Scientific reports 74 28091569
2021 Higher gametocyte production and mosquito infectivity in chronic compared to incident Plasmodium falciparum infections. Nature communications 73 33903595
2020 Conditional expression of PfAP2-G for controlled massive sexual conversion in Plasmodium falciparum. Science advances 67 32577509
2018 Inducible developmental reprogramming redefines commitment to sexual development in the malaria parasite Plasmodium berghei. Nature microbiology 65 30177743
2020 Strains used in whole organism Plasmodium falciparum vaccine trials differ in genome structure, sequence, and immunogenic potential. Genome medicine 63 31915075
2014 Endoplasmic reticulum stress triggers gametocytogenesis in the malaria parasite. The Journal of biological chemistry 63 24755215
2016 Proteome-wide analysis reveals widespread lysine acetylation of major protein complexes in the malaria parasite. Scientific reports 62 26813983
2019 Plasmodium falciparum sexual differentiation in malaria patients is associated with host factors and GDV1-dependent genes. Nature communications 60 31086187
2017 Adaptation of Plasmodium falciparum to its transmission environment. Nature ecology & evolution 59 29255304
2023 Regulators of male and female sexual development are critical for the transmission of a malaria parasite. Cell host & microbe 58 36634679
2009 Structural determinants of DNA binding by a P. falciparum ApiAP2 transcriptional regulator. Journal of molecular biology 57 19913037
2021 A cascade of transcriptional repression determines sexual commitment and development in Plasmodium falciparum. Nucleic acids research 49 34365503
2021 A heat-shock response regulated by the PfAP2-HS transcription factor protects human malaria parasites from febrile temperatures. Nature microbiology 48 34400833
2016 Selective sweep suggests transcriptional regulation may underlie Plasmodium vivax resilience to malaria control measures in Cambodia. Proceedings of the National Academy of Sciences of the United States of America 48 27911780
2010 The construction and use of log-odds substitution scores for multiple sequence alignment. PLoS computational biology 48 20657661
2020 From Genes to Transcripts, a Tightly Regulated Journey in Plasmodium. Frontiers in cellular and infection microbiology 46 33425787
2015 Specific expression and export of the Plasmodium falciparum Gametocyte EXported Protein-5 marks the gametocyte ring stage. Malaria journal 46 26315106
2021 The PfAP2-G2 transcription factor is a critical regulator of gametocyte maturation. Molecular microbiology 44 33368818
2023 Sexual differentiation in human malaria parasites is regulated by competition between phospholipid metabolism and histone methylation. Nature microbiology 42 37277533
2017 Capturing in vivo RNA transcriptional dynamics from the malaria parasite Plasmodium falciparum. Genome research 40 28416533
2021 Mechanisms of triggering malaria gametocytogenesis by AP2-G. Parasitology international 29 34119684
2023 Plasmodium falciparum adapts its investment into replication versus transmission according to the host environment. eLife 27 36916164
2020 Rrp6 Regulates Heterochromatic Gene Silencing via ncRNA RUF6 Decay in Malaria Parasites. mBio 26 32487761
2023 Characterization of the dual role of Plasmodium falciparum DNA methyltransferase in regulating transcription and translation. Nucleic acids research 25 37026483
2020 Disruption of the Plasmodium falciparum Life Cycle through Transcriptional Reprogramming by Inhibitors of Jumonji Demethylases. ACS infectious diseases 25 32272012
2010 From cradle to grave: RNA biology in malaria parasites. Wiley interdisciplinary reviews. RNA 25 21935891
2021 Single-Cell RNA Sequencing Reveals Cellular Heterogeneity and Stage Transition under Temperature Stress in Synchronized Plasmodium falciparum Cells. Microbiology spectrum 24 34232098
2019 The role of epigenetics and chromatin structure in transcriptional regulation in malaria parasites. Briefings in functional genomics 24 31220857
2017 A disrupted transsulphuration pathway results in accumulation of redox metabolites and induction of gametocytogenesis in malaria. Scientific reports 24 28091526
2022 A Dynamic and Combinatorial Histone Code Drives Malaria Parasite Asexual and Sexual Development. Molecular & cellular proteomics : MCP 23 35051657
2019 A patatin-like phospholipase functions during gametocyte induction in the malaria parasite Plasmodium falciparum. Cellular microbiology 23 31734953
2022 Identification of a novel AP2 transcription factor in zygotes with an essential role in Plasmodium ookinete development. PLoS pathogens 22 35947628
2021 A Randomized Clinical Trial to Compare Plasmodium falciparum Gametocytemia and Infectivity After Blood-Stage or Mosquito Bite-Induced Controlled Malaria Infection. The Journal of infectious diseases 22 32239171
2019 Predicting gene expression in the human malaria parasite Plasmodium falciparum using histone modification, nucleosome positioning, and 3D localization features. PLoS computational biology 20 31509524
2020 Metabolic regulation of sexual commitment in Plasmodium falciparum. Current opinion in microbiology 17 33053503
2016 Genomic variation in two gametocyte non-producing Plasmodium falciparum clonal lines. Malaria journal 17 27098483
2021 A 39-Amino-Acid C-Terminal Truncation of GDV1 Disrupts Sexual Commitment in Plasmodium falciparum. mSphere 16 34011691
2022 Plasmodium falciparum Sexual Commitment Rate Variation among Clinical Isolates and Diverse Laboratory-Adapted Lines. Microbiology spectrum 15 36409095
2021 H3K36 methylation reprograms gene expression to drive early gametocyte development in Plasmodium falciparum. Epigenetics & chromatin 15 33794978
2022 A Leak-Free Inducible CRISPRi/a System for Gene Functional Studies in Plasmodium falciparum. Microbiology spectrum 14 35510853
2021 PfAP2-G2 Is Associated to Production and Maturation of Gametocytes in Plasmodium falciparum via Regulating the Expression of PfMDV-1. Frontiers in microbiology 14 33537025
2025 Pink or blue: sex determination in malaria gametocytes. Trends in parasitology 2 41107154
2025 Transcription factor 25 modulates gametocytogenesis and ribosome biogenesis in the malaria parasite Plasmodium falciparum. Frontiers in cellular and infection microbiology 2 41210950
2025 Heterochromatin de novo formation and maintenance in Plasmodium falciparum. PLoS pathogens 1 40455742
2026 A single valine to leucine switch disrupts Plasmodium falciparum AP2-G DNA binding and reveals GDV1's role in ap2-g activation. Nature communications 0 41547993
2026 Molecular mechanisms involved in Plasmodium gametocytogenesis. Frontiers in microbiology 0 41716278
2026 A heterologous marker-free selection approach for CRISPR/Cas9-based gene editing in the malaria parasite Plasmodium falciparum. mSphere 0 41885428
2026 A divergent Plasmodium NEK4 acts as a key regulator driving the early events of meiosis. Nature communications 0 42120403
2026 Identification of a sequence element regulating H3K9 methylation at the ap2-g locus in Plasmodium falciparum. Scientific reports 0 42443261
2026 Persistence of Plasmodium falciparum DNA detection after antimalarial treatment and the implication of gametocytes: a prospective cohort study in a non-endemic setting. Microbiology spectrum 0 42684939
2025 A divergent Plasmodium NEK4 acts as a key regulator driving the early events of meiosis. bioRxiv : the preprint server for biology 0 41332573
2025 A divergent Plasmodium NEK4 acts as a key regulator driving the early events of meiosis. Research square 0 41510253