Affinage · Toxoplasma gondii

LEO1

Paf1/RNA polymerase II complex component LEO1 · UniProt S8ETE7

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

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

In Toxoplasma gondii, LEO1 is a polymerase-associated factor (Paf1 complex) subunit that physically associates with the GCN5b lysine acetyltransferase core complex, which also includes the co-activator ADA2-A, TFIID subunits, RRM proteins, and AP2-domain transcription factors, placing LEO1 within a transcription and chromatin-remodeling assembly (PMID:24391497). Beyond this single co-immunoprecipitation/mass-spectrometry identification (PMID:24391497), LEO1's direct functional role within this complex has not been characterized in the available corpus.

Mechanistic history

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

    It was unknown which factors partner with the GCN5b acetyltransferase in Toxoplasma; proteomics of the GCN5b core complex placed LEO1 within a transcriptional/chromatin-remodeling assembly, connecting a Paf1 subunit to acetyltransferase-driven gene regulation in the parasite.

    Evidence Co-immunoprecipitation followed by mass spectrometry of HA-tagged dominant-negative GCN5b in Toxoplasma gondii

    PMID:24391497

    Open questions at the time
    • No direct functional characterization of LEO1 itself within the complex
    • Interaction shown by single Co-IP/MS without reciprocal validation
    • No evidence for LEO1 substrates, target genes, or contribution to complex activity

Open questions

Synthesis pass · forward-looking unresolved questions
  • The direct molecular function of LEO1, whether the association with GCN5b is direct or bridged, and its individual contribution to transcription or parasite proliferation remain unresolved.
  • No genetic or biochemical dissection of LEO1 function
  • No structural or interaction-mapping data
  • No defined target genes or phenotype for LEO1 loss

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
ADA2-A [#0]AP2-DOMAIN TRANSCRIPTION FACTORS [#0]GCN5B (LYSINE ACETYLTRANSFERASE) [#0]RRM PROTEINS [#0]TFIID SUBUNITS [#0]
Complex memberships
GCN5b lysine acetyltransferase core complex (with ADA2-A, TFIID subunits, RRM proteins, AP2-domain transcription factors) [#0]Paf1 complex (LEO1 as polymerase-associated factor subunit) [#0]

Evidence

Reading pass · 1 per-paper finding extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2014 LEO1, a Paf1 complex subunit, was identified as part of the GCN5b 'core complex' in Toxoplasma gondii. Proteomics revealed that GCN5b (a lysine acetyltransferase) interacts with a core complex that includes the co-activator ADA2-A, TFIID subunits, LEO1 (polymerase-associated factor/Paf1 subunit), and RRM proteins, as well as AP2-domain transcription factors. Co-immunoprecipitation followed by mass spectrometry (proteomics) of HA-tagged dominant-negative GCN5b PLoS pathogens Medium 24391497

Source papers

Stage 0 corpus · 50 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2016 Dendrimer-RNA nanoparticles generate protective immunity against lethal Ebola, H1N1 influenza, and Toxoplasma gondii challenges with a single dose. Proceedings of the National Academy of Sciences of the United States of America 318 27382155
2014 Efficient genome engineering of Toxoplasma gondii using CRISPR/Cas9. PloS one 221 24971596
2004 RNA interference in protozoan parasites. Cellular microbiology 205 15104593
2014 Dual transcriptional profiling of mice and Toxoplasma gondii during acute and chronic infection. BMC genomics 162 25240600
2013 Combined action of nucleic acid-sensing Toll-like receptors and TLR11/TLR12 heterodimers imparts resistance to Toxoplasma gondii in mice. Cell host & microbe 159 23290966
2016 Illuminating uveitis: metagenomic deep sequencing identifies common and rare pathogens. Genome medicine 155 27562436
2005 Biosynthetic labeling of RNA with uracil phosphoribosyltransferase allows cell-specific microarray analysis of mRNA synthesis and decay. Nature biotechnology 153 15685165
2010 NALP1 influences susceptibility to human congenital toxoplasmosis, proinflammatory cytokine response, and fate of Toxoplasma gondii-infected monocytic cells. Infection and immunity 144 21098108
2019 An experimental genetically attenuated live vaccine to prevent transmission of Toxoplasma gondii by cats. Scientific reports 132 30728393
1996 Mechanisms of interferon-induced inhibition of Toxoplasma gondii replication in human retinal pigment epithelial cells. Infection and immunity 132 8926087
1984 Inhibition of growth of Toxoplasma gondii in cultured fibroblasts by human recombinant gamma interferon. Infection and immunity 131 6425215
2018 P2X7 receptor mediates NLRP3-dependent IL-1β secretion and parasite proliferation in Toxoplasma gondii-infected human small intestinal epithelial cells. Parasites & vectors 125 29291748
2009 Apicomplexan parasites co-opt host calpains to facilitate their escape from infected cells. Science (New York, N.Y.) 120 19342550
2016 Detection and visualization of differential splicing in RNA-Seq data with JunctionSeq. Nucleic acids research 108 27257077
2011 RNA interference in protozoan parasites: achievements and challenges. Eukaryotic cell 103 21764910
2016 Id2 reinforces TH1 differentiation and inhibits E2A to repress TFH differentiation. Nature immunology 100 27213691
2017 Development of CRISPR/Cas9 for Efficient Genome Editing in Toxoplasma gondii. Methods in molecular biology (Clifton, N.J.) 98 27709570
2015 Asexual expansion of Toxoplasma gondii merozoites is distinct from tachyzoites and entails expression of non-overlapping gene families to attach, invade, and replicate within feline enterocytes. BMC genomics 98 25757795
1994 Molecular characterization of a 65-kilodalton Toxoplasma gondii antigen expressed abundantly in the matrix of tissue cysts. Molecular and biochemical parasitology 97 7808478
1995 Inhibition of cytoplasmic and organellar protein synthesis in Toxoplasma gondii. Implications for the target of macrolide antibiotics. The Journal of clinical investigation 94 7814637
1997 A novel class of unconventional myosins from Toxoplasma gondii. Journal of molecular biology 90 9300060
1993 Cytokine mRNA in the central nervous system of SCID mice infected with Toxoplasma gondii: importance of T-cell-independent regulation of resistance to T. gondii. Infection and immunity 89 8406791
1990 Cloning, expression, and cDNA sequence of surface antigen P22 from Toxoplasma gondii. Molecular and biochemical parasitology 89 2290448
1990 Molecular cloning, sequencing and expression of human interferon-gamma-inducible indoleamine 2,3-dioxygenase cDNA. Biochemical and biophysical research communications 86 2109605
1994 The phylogeny of Neospora caninum and Toxoplasma gondii based on ribosomal RNA sequences. FEMS microbiology letters 85 8039658
2010 A complex small RNA repertoire is generated by a plant/fungal-like machinery and effected by a metazoan-like Argonaute in the single-cell human parasite Toxoplasma gondii. PLoS pathogens 84 20523899
2014 MicroRNA-132 dysregulation in Toxoplasma gondii infection has implications for dopamine signaling pathway. Neuroscience 82 24657774
2013 Transcriptional analysis of murine macrophages infected with different Toxoplasma strains identifies novel regulation of host signaling pathways. PLoS pathogens 79 24367253
2006 Changes in the expression of human cell division autoantigen-1 influence Toxoplasma gondii growth and development. PLoS pathogens 79 17069459
1999 Phylogenetic analysis based on full-length large subunit ribosomal RNA gene sequence comparison reveals that Neospora caninum is more closely related to Hammondia heydorni than to Toxoplasma gondii. International journal for parasitology 76 10608441
2012 Admixture and recombination among Toxoplasma gondii lineages explain global genome diversity. Proceedings of the National Academy of Sciences of the United States of America 71 22847430
2020 Pathogenic Infection in Male Mice Changes Sperm Small RNA Profiles and Transgenerationally Alters Offspring Behavior. Cell reports 69 32348768
2014 Lysine acetyltransferase GCN5b interacts with AP2 factors and is required for Toxoplasma gondii proliferation. PLoS pathogens 63 24391497
2011 Protein arginine methylation in parasitic protozoa. Eukaryotic cell 50 21685318
2006 Different neurotropic pathogens elicit neurotoxic CCR9- or neurosupportive CXCR3-expressing microglia. Journal of immunology (Baltimore, Md. : 1950) 49 16951324
2006 Comparison between two real-time PCR assays and a nested-PCR for the detection of Toxoplasma gondii. Acta bio-medica : Atenei Parmensis 49 17172185
1998 Phylogenetic analysis of coccidia based on 18S rDNA sequence comparison indicates that Isospora is most closely related to Toxoplasma and Neospora. The Journal of eukaryotic microbiology 49 9561772
2017 Voltage-dependent calcium channel signaling mediates GABAA receptor-induced migratory activation of dendritic cells infected by Toxoplasma gondii. PLoS pathogens 48 29216332
1992 Physical and genetic mapping of cloned ribosomal DNA from Toxoplasma gondii: primary and secondary structure of the 5S gene. Gene 48 1601300
2005 A novel class of dual-family immunophilins. The Journal of biological chemistry 47 15845546
2017 Induction of Protective Immunity against Toxoplasma gondii in Mice by Nucleoside Triphosphate Hydrolase-II (NTPase-II) Self-amplifying RNA Vaccine Encapsulated in Lipid Nanoparticle (LNP). Frontiers in microbiology 46 28424680
2009 Evidence for a Single Origin of the 35 kb Plastid DNA in Apicomplexans. Protist 45 23196113
1989 Cloning of cDNAs encoding a 28 kilodalton antigen of Toxoplasma gondii. Molecular and biochemical parasitology 45 2710166
1970 The RNA of toxoplasma gondii. Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.) 44 5414249
2014 Knockout of leucine aminopeptidase in Toxoplasma gondii using CRISPR/Cas9. International journal for parasitology 41 25444863
2003 Pleiotropic effect due to targeted depletion of secretory rhoptry protein ROP2 in Toxoplasma gondii. Journal of cell science 41 12711703
1998 Upstream elements required for expression of nucleoside triphosphate hydrolase genes of Toxoplasma gondii. Molecular and biochemical parasitology 41 9657328
2021 Direct Nanopore Sequencing of mRNA Reveals Landscape of Transcript Isoforms in Apicomplexan Parasites. mSystems 40 33688018
1994 Temporal differences in the expression of mRNA for IL-10 and IFN-gamma in the brains and spleens of C57BL/10 mice infected with Toxoplasma gondii. Parasite immunology 39 7970867
1974 Protection against Toxoplasma gondii in mice immunized with Toxoplasma cell fractions, RNA and synthetic polyribonucleotides. Immunology 38 4215743