Affinage · Toxoplasma gondii

AP2VIII2

AP2 domain transcription factor AP2VIII-2 · UniProt S8GJZ9

Annotated
2026-09-10
12 papers in source corpus 1 papers cited in narrative 1 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

AP2VIII-2 is a transcription-factor component of a chromatin-regulatory complex that shapes stage-specific gene expression in Toxoplasma gondii (PMID:40217127). It physically associates with the ISWI-family chromatin remodeller TgSNF2h and the scaffold protein TgRFTS to form a core complex; within this complex TgSNF2h insulates highly transcribed genes from silenced neighbours and exerts epistatic control over MORC, a key regulator of sexual commitment (PMID:40217127). Depletion of TgRFTS phenocopies TgSNF2h knockdown by restricting chromatin access and altering local gene expression (PMID:40217127). Beyond this single complex-level characterization, no further mechanistic detail — including AP2VIII-2's direct DNA-binding targets or its individual contribution separable from TgSNF2h — has been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 1 step
  1. 2025 High

    The question of how a specific ApiAP2 transcription factor connects to chromatin remodelling was answered by placing AP2VIII-2 in a defined complex with TgSNF2h and TgRFTS that controls chromatin accessibility and stage-specific gene regulation.

    Evidence Co-immunoprecipitation/proteomics to define the complex, conditional knockdown with chromatin accessibility and gene-expression readouts, and epistasis analysis relative to MORC in Toxoplasma gondii

    PMID:40217127

    Open questions at the time
    • The direct DNA-binding sites and target genes of AP2VIII-2 itself are not resolved
    • The specific contribution of AP2VIII-2 loss (versus TgSNF2h or TgRFTS depletion) to the observed phenotypes is not separated
    • The structural organization and stoichiometry of the AP2VIII-2/TgSNF2h/TgRFTS complex are undefined

Open questions

Synthesis pass · forward-looking unresolved questions
  • Whether AP2VIII-2 directs sequence-specific targeting of the remodelling complex to insulated loci and how it governs MORC-dependent sexual commitment remain unresolved.
  • No genome-wide occupancy map for AP2VIII-2 has been established
  • The mechanism by which the complex insulates transcribed genes from silenced neighbours is not defined at the molecular level

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
MORC (EPISTATIC TARGET; REGULATOR OF SEXUAL COMMITMENT)TGRFTS (SCAFFOLD PROTEIN)TGSNF2H (ISWI-FAMILY CHROMATIN REMODELLER)
Complex memberships
AP2VIII-2 / TgSNF2h / TgRFTS core chromatin-remodelling complex

Evidence

Reading pass · 1 per-paper finding extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2025 AP2VIII-2 forms a core complex with the ISWI-family chromatin remodeller TgSNF2h and the scaffold protein TgRFTS in Toxoplasma gondii. Depletion of TgRFTS phenocopies TgSNF2h knockdown, restricting chromatin access and altering local gene expression. At the genomic level, TgSNF2h (with AP2VIII-2 as a partner) insulates highly transcribed genes from silenced neighbours and exerts epistatic control over MORC, a key regulator of sexual commitment. Co-immunoprecipitation / proteomics to identify the complex; conditional knockdown with phenotypic readout (chromatin accessibility, gene expression); epistasis analysis relative to MORC Nature microbiology High 40217127

Source papers

Stage 0 corpus · 12 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2010 Coordinated progression through two subtranscriptomes underlies the tachyzoite cycle of Toxoplasma gondii. PloS one 234 20865045
2018 The Epigenome, Cell Cycle, and Development in Toxoplasma. Annual review of microbiology 51 29932347
2010 The construction and use of log-odds substitution scores for multiple sequence alignment. PLoS computational biology 48 20657661
2008 Repeated secondary loss of adaptin complex genes in the Apicomplexa. Parasitology international 36 19146987
2012 Cactin is essential for G1 progression in Toxoplasma gondii. Molecular microbiology 23 22486860
2014 Distinct strains of Toxoplasma gondii feature divergent transcriptomes regardless of developmental stage. PloS one 22 25393307
2008 New eukaryotic systematics: a phylogenetic perspective of developmental gene expression in the Apicomplexa. International journal for parasitology 12 18983845
2024 Apicomplexan mitoribosome from highly fragmented rRNAs to a functional machine. Nature communications 9 39690155
2025 An ISWI-related chromatin remodeller regulates stage-specific gene expression in Toxoplasma gondii. Nature microbiology 7 40217127
2022 Genomic insights into host and parasite interactions during intracellular infection by Toxoplasma gondii. PloS one 2 36178892
2026 Host-cell dependent epigenetic profiles associated with survival outcomes in T. gondii infection. Epigenetics & chromatin 0 42087241
2025 HIV-1 Tat favors the multiplication of Mycobacterium tuberculosis and Toxoplasma by inhibiting clathrin-mediated endocytosis and autophagy. PLoS pathogens 0 40934260