{"gene":"ISYNA1","run_date":"2026-06-10T01:55:23","timeline":{"discoveries":[{"year":1984,"finding":"The yeast INO1 gene (ortholog of ISYNA1) encodes myo-inositol-1-phosphate synthase, the enzyme catalyzing the first committed step in inositol biosynthesis; the cloned gene complemented ino1 loss-of-function mutants and restored cross-reactive enzyme protein, confirming its identity as the structural gene for inositol-1-phosphate synthase.","method":"Genetic complementation of ino1 auxotrophs with cloned DNA; antibody cross-reactivity assay for enzyme protein; Southern blot confirming unique genomic locus","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct enzymatic complementation plus immunological confirmation, foundational cloning paper replicated by subsequent studies","pmids":["6374665"],"is_preprint":false},{"year":1986,"finding":"INO1 (ISYNA1 ortholog) expression and inositol-1-phosphate synthase activity are transcriptionally repressed 12-fold by exogenous inositol and 33-fold by inositol plus choline combined; repression requires regulatory genes INO2 and INO4 (loss-of-function causes auxotrophy), and constitutive overexpression occurs in opi1 mutants.","method":"RNA blot hybridization under defined growth conditions; enzyme activity assays; genetic analysis of ino2, ino4, opi1 mutants","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (RNA blot, enzyme assay, genetics), replicated across many subsequent studies","pmids":["3025587"],"is_preprint":false},{"year":1981,"finding":"The INO1 locus (structural gene for inositol-1-phosphate synthase) was mapped to chromosome X of S. cerevisiae between ura2 and cdc6; ~70% of inositol auxotrophs carry ino1 alleles, and INO1 null mutations are not suppressible by known nonsense suppressors, suggesting premature termination is lethal.","method":"Trisomic analysis, genetic complementation, chromosomal mapping","journal":"Genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — classical genetics with multiple alleles and mapping, single lab","pmids":["17249096"],"is_preprint":false},{"year":1991,"finding":"A 9-bp repeated element (consensus 5'-CATGTGAAAT-3'), termed UAS(INO), in the INO1 promoter is necessary and sufficient for inositol/choline-responsive transcriptional regulation; the smallest active fragment was 40 bp containing one copy of this element.","method":"INO1 promoter-lacZ fusions with systematic deletions and oligonucleotide insertions; beta-galactosidase reporter assays","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Strong — promoter dissection with multiple deletion constructs and heterologous reporter, mechanistic element defined","pmids":["2027776"],"is_preprint":false},{"year":1994,"finding":"The positive regulators Ino2p and Ino4p (both bHLH proteins) form a heterodimeric complex that binds to the INO1 promoter UAS(INO) element; neither protein alone binds DNA, and the complex is identical in mobility to that formed with whole-cell extracts.","method":"In vitro translation of Ino2p and Ino4p; electrophoretic mobility shift assay (EMSA); immunoprecipitation confirming Ino2p–Ino4p protein–protein interaction in absence of DNA; competition with bHLH consensus oligonucleotide","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstitution in vitro with purified translated proteins, EMSA, immunoprecipitation, multiple orthogonal methods in one study","pmids":["8195172"],"is_preprint":false},{"year":1992,"finding":"A dominant CSE1 mutation causes choline-dependent repression of INO1 (ISYNA1 ortholog) and inositol-1-phosphate synthase; choline-dependent repression requires metabolism of choline via the CDP-choline pathway, as blocking this pathway abolishes choline-induced INO1 repression.","method":"INO1-lacZ promoter fusions; Northern blot; enzyme activity assay; genetic epistasis with CDP-choline pathway mutations","journal":"Journal of biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reporter fusions plus epistasis analysis, single lab","pmids":["1587797"],"is_preprint":false},{"year":1995,"finding":"The SCS2 gene (encoding an integral membrane protein, VAP homolog) is a multicopy suppressor of ire15 and CSE1 mutations affecting INO1 expression; SCS2 and INO2/SCS1 (a positive regulator) both suppress these regulatory mutations, placing Scs2p in the INO1 regulatory pathway.","method":"Multicopy suppressor screen; genetic complementation; sequence analysis","journal":"Journal of biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic suppressor screen with complementation, single lab","pmids":["8537323"],"is_preprint":false},{"year":1996,"finding":"Repression of INO1 transcription in response to inositol requires ongoing phosphatidylcholine (PC) biosynthesis but is independent of the specific pathway (methylation vs. CDP-choline) used for PC synthesis; intermediates in these pathways are not the regulatory signal, and repression correlates with the rate of PC synthesis sustaining growth rather than absolute PC proportion.","method":"INO1-lacZ reporter assays; genetic analysis of PC biosynthesis mutants (cho2, opi3, cki1, pct1); growth and phospholipid measurements","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple genetic backgrounds tested with reporter assay, single lab","pmids":["8810347"],"is_preprint":false},{"year":1996,"finding":"Individual UAS(INO) elements in the INO1 promoter differ in functionality; most native INO1 promoter elements are inactive individually, whereas all CHO2 promoter elements are active, explaining differential regulation between co-regulated genes; elements with C or A at the 5' position of the consensus are functional.","method":"Systematic placement of individual promoter fragments upstream of CYC1-lacZ reporter; beta-galactosidase assay; oligonucleotide mutagenesis of consensus first position","journal":"Yeast (Chichester, England)","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — promoter mutagenesis with reporter assay, single lab, mechanistic detail on cis-element function","pmids":["8810039"],"is_preprint":false},{"year":1997,"finding":"Inactivation of Sec14p (phosphatidylinositol/phosphatidylcholine transfer protein) in a cki1 background leads to increased phosphatidylcholine turnover via a phospholipase D-like mechanism, which derepresses INO1 (ISYNA1 ortholog) transcription, establishing a regulatory link between PC turnover and INO1 expression.","method":"Genetic epistasis (sec14ts cki1 double mutants); choline excretion assay; INO1-lacZ reporter; enzyme assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with reporter assay, single lab","pmids":["9252414"],"is_preprint":false},{"year":1999,"finding":"The REG1-encoded regulatory subunit of the Glc7 phosphatase is required for repression of INO1; reg1 loss-of-function suppresses inositol auxotrophy of ino4 and ino2 missense mutants and causes constitutive INO1 expression, placing Reg1p/Glc7 phosphatase activity as a positive component of INO1 repression. Separately, Snf4/Snf1 kinase activity promotes INO1 activation, as dominant SNF4 mutations suppress INO1 derepression defects.","method":"Genetic suppressor screen; INO1-lacZ reporter assays; two-hybrid interaction assay for Snf4-Snf1 interaction","journal":"Genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic suppressor screen with reporter confirmation, single lab","pmids":["10224244"],"is_preprint":false},{"year":1999,"finding":"REG1 (Glc7 phosphatase regulatory subunit) loss-of-function causes constitutive INO1 expression independently of OPI1; REG1 suppresses ino4 missense alleles but not ino2/ino4 null mutations; OPI1 protein does not bind UAS(INO) or interact with Ino2p or Ino4p directly.","method":"INO1-lacZ reporter assays in multiple mutant backgrounds; two-hybrid assays testing Opi1p-UAS(INO), Opi1p-Ino2p, Opi1p-Ino4p interactions (all negative)","journal":"Genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple genetic backgrounds with reporter assay; negative two-hybrid results are informative; single lab","pmids":["10747047"],"is_preprint":false},{"year":2001,"finding":"Both lithium and valproate decrease intracellular myo-inositol levels and increase expression of INO1 (ISYNA1 ortholog) and INO2; valproate may inhibit Ino1p-catalyzed synthesis of inositol-1-phosphate directly, as valproate treatment decreases inositol monophosphate synthesis; the opi1 mutant is more resistant to lithium (but not valproate) growth inhibition, indicating different mechanisms for the two drugs.","method":"Northern blot for INO1/INO2 mRNA; inositol mass measurement; inositol monophosphate synthesis assay; growth assays in opi1 mutant","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — biochemical assays plus genetics in yeast, single lab","pmids":["11278273"],"is_preprint":false},{"year":2001,"finding":"The Snf1 kinase is required for INO1 activation; mutations in ACC1 (acetyl-CoA carboxylase) and FAS1 (fatty acid synthase beta subunit) suppress the inositol auxotrophy of snf1Δ strains by reducing Acc1 activity, which is elevated in snf1Δ cells because Snf1 normally phosphorylates and inactivates Acc1p; reduced fatty acid synthesis rate restores INO1 expression.","method":"Genetic suppressor screen; in vitro Acc1 enzyme activity assay; soraphen A (Acc1 inhibitor) growth sensitivity; INO1-lacZ reporter; conditional ACC1 expression","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple orthogonal methods (genetics, in vitro enzyme assay, chemical inhibitor, conditional expression) establishing Snf1→Acc1→INO1 pathway","pmids":["11486011"],"is_preprint":false},{"year":2001,"finding":"The Isw2p-Itc1p chromatin-remodeling complex represses INO1 expression; deletion of either ISW2 or ITC1 in a hac1Δ background derepresses INO1 even under inositol-repressing conditions; a truncated dominant-negative form of Itc1p suppresses the hac1Δ inositol auxotrophy by impairing Isw2p-Itc1p repressor function.","method":"Multicopy suppressor screen; INO1-lacZ reporter; genetic epistasis (isw2Δ itc1Δ hac1Δ); dominant-negative truncation analysis","journal":"Journal of bacteriology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reporter assays with genetic epistasis and dominant-negative construct, single lab","pmids":["11489850"],"is_preprint":false},{"year":2002,"finding":"The unfolded protein response (UPR) pathway (Ire1p/Hac1p) is required for sustained high-level INO1 expression under inositol starvation but not for transient derepression; inactivation of Sec14p activates the UPR; the UPR is not required for INO1 regulation in the sec14ts cki1Δ background.","method":"Genetic epistasis (ire1Δ, hac1Δ combined with sec14ts cki1Δ); INO1-lacZ reporter; UPR reporter assays","journal":"Genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with reporter assays, single lab","pmids":["12242221"],"is_preprint":false},{"year":2003,"finding":"Scs2p (yeast VAP homolog) regulates INO1 expression by controlling phosphatidylcholine synthesis through the CDP-choline pathway; scs2Δ cells have reduced INO1 mRNA but normal INO1 promoter-driven reporter activity, suggesting Scs2p acts post-transcriptionally or on mRNA stability; disruption of CDP-choline pathway genes rescues INO1 expression defect in scs2Δ cells.","method":"INO1 mRNA Northern blot; INO1 promoter-lacZ reporter; phospholipid composition analysis; genetic epistasis with CDP-choline pathway mutants","journal":"Journal of biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple assays (Northern, reporter, lipidomics, genetics) in single lab","pmids":["12761300"],"is_preprint":false},{"year":2004,"finding":"Activation of INO1 (ISYNA1 ortholog) recruits the gene locus to the nuclear periphery; repressed INO1 is distributed throughout the nucleoplasm; recruitment requires the transcriptional activator Hac1p (produced upon UPR induction) and the integral membrane protein Scs2p (which antagonizes Opi1p repressor); artificial tethering of INO1 to the nuclear membrane enables activation in the absence of Scs2p.","method":"Fluorescence microscopy of GFP-tagged INO1 locus; genetic analysis of hac1Δ, scs2Δ, opi1Δ; artificial membrane tethering experiment","journal":"PLoS biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct live imaging of locus position, multiple genetic backgrounds, and functional rescue by artificial tethering — multiple orthogonal methods","pmids":["15455074"],"is_preprint":false},{"year":2004,"finding":"The UPR pathway plays a functional role in membrane trafficking under secretory stress; UPR loss-of-function (hac1Δ, ire1Δ) exacerbates secretory defects and slows vacuolar protein transport; high UPR induction under secretory stress does not correlate with elevated INO1 expression, indicating UPR and INO1 regulatory signals are separable.","method":"Carboxypeptidase Y transit time assay; genetic interaction analysis (Sec– mutations with ire1Δ/hac1Δ); INO1-lacZ reporter; UPR reporter","journal":"Genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple genetic backgrounds with biochemical trafficking assay and reporter, single lab","pmids":["15371354"],"is_preprint":false},{"year":2004,"finding":"In Mycobacterium tuberculosis, four active-site residues of inositol-1-phosphate synthase (Ino1, homolog of ISYNA1) are essential for enzymatic activity; site-directed mutagenesis of these residues abolished activity; a D310N mutation caused loss of the active-site Zn²⁺ ion and a conformational change in the NAD⁺ cofactor; the ino1 gene is essential for mycobacterial growth and virulence.","method":"Site-directed mutagenesis of four active-site residues; enzyme activity assay; metal ion analysis; NAD⁺ cofactor conformational assessment; conditional knockout in macrophages and SCID mice","journal":"Molecular microbiology","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — reconstitution with mutagenesis and cofactor analysis, but bacterial enzyme not the mammalian protein","pmids":["14763976"],"is_preprint":false},{"year":2005,"finding":"Snf1 kinase and Sit4 phosphatase have opposing roles in INO1 transcription: Snf1 promotes activation while Sit4 represses it; both regulate binding of TATA-binding protein (TBP) to the INO1 promoter as shown by chromatin immunoprecipitation; sit4 mutation suppresses snf1Δ inositol auxotrophy; TOR signaling (via rapamycin) reduces INO1 activation through Sit4.","method":"Chromatin immunoprecipitation (ChIP) for TBP at INO1 promoter; genetic suppressor analysis; rapamycin treatment; INO1-lacZ reporter","journal":"Genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP assay directly showing TBP recruitment, plus genetic epistasis and pharmacological intervention, single lab but multiple orthogonal methods","pmids":["15716495"],"is_preprint":false},{"year":2010,"finding":"Interaction of a DNA 'zip code' (11-bp memory recruitment sequence, MRS) in the INO1 promoter with the nuclear pore complex (NPC) protein Nup100 controls both peripheral targeting of recently repressed INO1 and incorporation of histone variant H2A.Z; loss of MRS or Nup100 abolishes INO1 transcriptional memory, leading to nucleoplasmic localization and slower reactivation.","method":"Fluorescence microscopy of INO1 locus position; H2A.Z chromatin immunoprecipitation; promoter MRS deletion analysis; nup100Δ genetic analysis; reactivation kinetics assay","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct locus imaging, ChIP for histone variant, promoter deletion, and functional reactivation kinetics — multiple orthogonal methods","pmids":["20932479"],"is_preprint":false},{"year":2010,"finding":"Complete derepression of INO1 transcription requires cooperative binding of both the Ino2p-Ino4p bHLH heterodimer to UAS(INO) sites in the INO1 promoter and Cbf1p binding to distal sites encompassing the upstream SNA3 ORF; Cbf1p binding requires prior Ino2p-Ino4p binding and vice versa; Cbf1p binding is required for recruitment of the ISW2 chromatin-remodeling complex to UAS(INO) sites.","method":"Chromatin immunoprecipitation (ChIP) for Cbf1p, Ino2p, Ino4p, and ISW2 at INO1 promoter; INO1-lacZ reporter in cbf1Δ, ino2Δ, ino4Δ, isw2Δ mutants","journal":"Eukaryotic cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP for multiple factors with genetic epistasis and reporter assay, cooperative binding mechanism defined","pmids":["20935143"],"is_preprint":false},{"year":2011,"finding":"Rat Isyna1 (myo-inositol-3-phosphate synthase gene) is regulated by DNA methylation in a tissue-specific manner; in vitro methylation of the promoter suppresses transcription; a specific CpG residue in the -700 to -500 bp region is required for promoter activity in neuronal cells; a tissue-specific differentially methylated region (T-DMR) between +450 and +650 bp correlates inversely with mRNA levels across tissues.","method":"Transfection with in vitro methylated promoter constructs; Southern blot with methylation-sensitive restriction enzyme; CpG methylation profiling; CpG mutation analysis by transfection","journal":"Epigenomics","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro methylation/transfection assay with mutagenesis of specific CpG, single lab","pmids":["21841945"],"is_preprint":false},{"year":2015,"finding":"INO1 transcriptional memory involves interchromosomal clustering: during memory, both alleles of INO1 cluster together in diploids, and endogenous INO1 clusters with an ectopic copy in haploids; memory clustering requires Nup100 and two sets of DNA zip codes (those for active targeting and those for memory targeting); clustering is cell cycle-regulated during memory but peripheral localization is not.","method":"Fluorescence microscopy of tagged INO1 loci in diploid and haploid cells; genetic analysis of nup100Δ and zip code mutations; cell cycle staging","journal":"Microbial cell (Graz, Austria)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct locus imaging in multiple genetic backgrounds, single lab","pmids":["26688804"],"is_preprint":false},{"year":2016,"finding":"Human ISYNA1 (inositol-3-phosphate synthase) is a direct transcriptional target of p53; p53 activates ISYNA1 expression through a p53 response element in the seventh exon; ectopic ISYNA1 expression increases intracellular myo-inositol levels and suppresses tumor cell growth; ISYNA1 knockdown causes resistance to adriamycin treatment, placing ISYNA1 downstream of p53 in growth suppression.","method":"Microarray screening followed by p53 induction; chromatin immunoprecipitation for p53 at ISYNA1 response element; myo-inositol measurement after ISYNA1 overexpression; cell proliferation assay; siRNA knockdown with drug treatment","journal":"International journal of oncology","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP identifying p53 response element, functional myo-inositol measurement, KD/OE with defined phenotype, multiple orthogonal methods in single lab","pmids":["27035231"],"is_preprint":false},{"year":2020,"finding":"ISYNA1 acts as a tumor suppressor downstream of MSI2 (Musashi2) in pancreatic cancer; MSI2 represses ISYNA1 expression (dependent on wild-type p53); ISYNA1 silencing promotes cell proliferation and cell cycle progression by inhibiting p21, and enhances migration/invasion by upregulating ZEB-1; MSI2 silencing-induced suppression of migration is rescued by ISYNA1 knockdown, defining an MSI2→ISYNA1→p21/ZEB-1 pathway.","method":"siRNA knockdown and overexpression of ISYNA1 and MSI2; cell proliferation and cell cycle assays; migration/invasion assays; Western blot for p21 and ZEB-1; rescue experiments","journal":"Journal of cellular and molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — epistasis by rescue experiment, multiple cellular phenotype readouts, single lab","pmids":["32779876"],"is_preprint":false},{"year":2022,"finding":"INO1 transcriptional memory involves RNAPII-independent H3K4 dimethylation (H3K4me2) that is mitotically heritable; H3K4me2 at the INO1 locus requires Nup100, SET3C, and the Leo1 subunit of the Paf1 complex, but not RNAPII; upon loss of an essential transcription factor, this H3K4me2 is inherited through multiple cell cycles; COMPASS (the H3K4 methyltransferase) physically interacts with SET3C (the potential H3K4me2 reader), suggesting a spreading/re-incorporation mechanism.","method":"ChIP for H3K4me2 after RNAPII depletion; genetic analysis of nup100Δ, set3c, leo1Δ mutants; cell cycle tracking of histone mark inheritance; co-immunoprecipitation of COMPASS and SET3C","journal":"eLife","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP, genetic epistasis, protein interaction (Co-IP), and cell-cycle inheritance assay — multiple orthogonal methods in single study","pmids":["35579426"],"is_preprint":false}],"current_model":"ISYNA1 encodes myo-inositol-3-phosphate synthase (inositol-1-phosphate synthase), the rate-limiting enzyme catalyzing the first committed step in myo-inositol biosynthesis from glucose-6-phosphate; in yeast (INO1 ortholog) its transcription is tightly regulated by phospholipid metabolic status through a UAS(INO) promoter element bound by the Ino2p-Ino4p bHLH heterodimer and repressed by Opi1p, with additional control by the Snf1 kinase/Sit4 phosphatase balance affecting TBP recruitment, the Isw2p-Itc1p chromatin remodeling complex, and NPC-mediated gene positioning that confers epigenetic transcriptional memory via RNAPII-independent H3K4me2; in mammalian cells, human ISYNA1 is a direct p53 transcriptional target that increases intracellular myo-inositol to suppress tumor cell growth, and its expression is also regulated by tissue-specific DNA methylation and suppressed by MSI2 to promote cancer progression via a ISYNA1–p21/ZEB-1 axis."},"narrative":{"mechanistic_narrative":"ISYNA1 (and its yeast ortholog INO1) encodes myo-inositol-3-phosphate synthase, the enzyme catalyzing the first committed, rate-limiting step of myo-inositol biosynthesis [PMID:6374665]. Active-site mutagenesis of the homologous enzyme establishes that catalysis depends on a defined set of active-site residues, a bound Zn²⁺ ion, and an NAD⁺ cofactor [PMID:14763976]. In yeast, INO1 has served as a paradigm for transcriptional control coupled to lipid metabolism: its expression is repressed by inositol and choline and depends on the positive regulators Ino2p and Ino4p, two bHLH proteins that heterodimerize and bind the UAS(INO) promoter element, while neither binds DNA alone [PMID:3025587, PMID:8195172, PMID:2027776]. Full derepression additionally requires cooperative Cbf1p binding at distal sites and recruitment of the Isw2p-Itc1p chromatin-remodeling complex [PMID:20935143, PMID:11489850]. The repressing signal is the rate of phosphatidylcholine biosynthesis rather than any specific pathway intermediate, linking INO1 output to membrane phospholipid flux [PMID:8810347, PMID:9252414]. INO1 transcription is further tuned by opposing Snf1 kinase and Sit4/Glc7 phosphatase activities that control TBP recruitment to the promoter, with Snf1 acting in part through phosphoinactivation of Acc1p [PMID:15716495, PMID:11486011, PMID:10224244]. The locus is a model for nuclear-position-dependent gene regulation: activation recruits INO1 to the nuclear periphery via Scs2p and the activator Hac1p [PMID:15455074], and a promoter DNA 'zip code' interacting with the nucleoporin Nup100 confers mitotically heritable transcriptional memory through interchromosomal clustering, H2A.Z incorporation, and RNAPII-independent H3K4me2 deposited via SET3C, Leo1/Paf1, and COMPASS [PMID:20932479, PMID:26688804, PMID:35579426]. In mammalian cells, human ISYNA1 is a direct p53 transcriptional target whose induction raises intracellular myo-inositol and suppresses tumor cell growth [PMID:27035231], and it acts as a tumor suppressor downstream of MSI2 through an ISYNA1→p21/ZEB-1 axis, with its expression also controlled by tissue-specific DNA methylation [PMID:32779876, PMID:21841945].","teleology":[{"year":1984,"claim":"Established the molecular identity of the gene by showing it is the structural gene for the inositol biosynthetic enzyme, anchoring all downstream mechanistic work.","evidence":"Genetic complementation of ino1 auxotrophs with cloned DNA plus immunological detection of enzyme protein in yeast","pmids":["6374665"],"confidence":"High","gaps":["Did not resolve enzyme catalytic mechanism or cofactor requirements","Mammalian ortholog function not addressed"]},{"year":1986,"claim":"Defined the gene as inositol/choline-repressible and identified the trans-acting regulators (INO2, INO4 positive; OPI1 negative) that control its expression.","evidence":"RNA blot, enzyme activity assays, and genetic analysis of ino2/ino4/opi1 mutants in yeast","pmids":["3025587"],"confidence":"High","gaps":["Did not identify the cis-element bound by regulators","Molecular nature of the repressing signal unknown"]},{"year":1991,"claim":"Mapped regulation to a discrete promoter element, showing a single UAS(INO) repeat is necessary and sufficient for inositol/choline-responsive control.","evidence":"Promoter-lacZ deletion/insertion reporter dissection in yeast","pmids":["2027776"],"confidence":"High","gaps":["Did not identify the protein binding the element","Differential activity among individual elements not yet resolved"]},{"year":1994,"claim":"Demonstrated the mechanistic basis of positive regulation: Ino2p and Ino4p heterodimerize and only the complex binds UAS(INO).","evidence":"In vitro translation, EMSA, and co-immunoprecipitation of Ino2p-Ino4p in yeast","pmids":["8195172"],"confidence":"High","gaps":["Did not address how the repressor counteracts this complex","Chromatin context of binding not examined"]},{"year":1996,"claim":"Resolved the nature of the repressing signal, showing repression tracks the rate of phosphatidylcholine biosynthesis rather than any specific pathway or intermediate.","evidence":"Reporter assays across PC biosynthesis mutants with phospholipid measurements in yeast","pmids":["8810347","8810039"],"confidence":"Medium","gaps":["Did not identify the molecular sensor transducing PC flux to the promoter","Did not connect signal to OPI1 mechanism"]},{"year":2001,"claim":"Identified opposing kinase/phosphatase and metabolic inputs (Snf1, Acc1, Reg1/Glc7) that set the activation threshold, integrating energy and fatty-acid metabolism with inositol gene control.","evidence":"Genetic suppressor screens, in vitro Acc1 enzyme assays, chemical inhibition, and reporters in yeast","pmids":["11486011","10224244","10747047"],"confidence":"High","gaps":["Did not show direct promoter-level mechanism of Snf1/Sit4 action","Mammalian relevance untested"]},{"year":2005,"claim":"Showed how kinase/phosphatase balance acts mechanistically at the promoter by controlling TBP recruitment, linking TOR signaling to inositol gene transcription.","evidence":"ChIP for TBP, genetic epistasis, and rapamycin treatment in yeast","pmids":["15716495"],"confidence":"High","gaps":["Did not define the chromatin steps downstream of TBP recruitment"]},{"year":2010,"claim":"Defined cooperative activation requiring both the Ino2p-Ino4p heterodimer and Cbf1p, with Cbf1p directing ISW2 chromatin remodeler recruitment.","evidence":"ChIP for multiple factors with genetic epistasis and reporter assays in yeast","pmids":["20935143","11489850"],"confidence":"High","gaps":["Order of remodeling and transcription factor loading not fully resolved"]},{"year":2010,"claim":"Established the gene as a model for spatial and epigenetic transcriptional memory, linking promoter zip codes and the nuclear pore to histone variant deposition and faster reactivation.","evidence":"Locus imaging, H2A.Z ChIP, promoter MRS deletion, and nup100Δ analysis in yeast","pmids":["20932479","15455074","26688804"],"confidence":"High","gaps":["Mechanism connecting NPC contact to histone variant incorporation incomplete","Conservation of positioning memory in mammals untested"]},{"year":2016,"claim":"Connected the gene to mammalian tumor suppression by establishing human ISYNA1 as a direct p53 target whose myo-inositol output restrains cell growth.","evidence":"p53 ChIP at a response element, myo-inositol measurement, and knockdown/overexpression with drug response in human cells","pmids":["27035231"],"confidence":"High","gaps":["Mechanism by which elevated myo-inositol suppresses growth not defined","Did not address upstream regulators of ISYNA1 in cancer"]},{"year":2020,"claim":"Placed ISYNA1 in an oncogenic regulatory circuit as a p53-dependent target repressed by MSI2, acting through p21 and ZEB-1 to control proliferation and invasion.","evidence":"Knockdown/overexpression of ISYNA1 and MSI2, phenotypic assays, and rescue experiments in pancreatic cancer cells","pmids":["32779876"],"confidence":"Medium","gaps":["Direct biochemical link between ISYNA1 enzymatic output and p21/ZEB-1 regulation unresolved","Single-lab cellular study without in vivo validation"]},{"year":2022,"claim":"Refined the chromatin basis of transcriptional memory by showing RNAPII-independent, mitotically heritable H3K4me2 deposited via SET3C, Leo1/Paf1, and COMPASS.","evidence":"ChIP after RNAPII depletion, genetic epistasis, cell-cycle inheritance tracking, and COMPASS-SET3C co-IP in yeast","pmids":["35579426"],"confidence":"High","gaps":["Reader-to-methyltransferase spreading mechanism inferred, not directly reconstituted","Relevance to mammalian ISYNA1 unknown"]},{"year":null,"claim":"How the enzymatic product myo-inositol mechanistically drives mammalian growth suppression, and whether the yeast nuclear-memory paradigm operates at human ISYNA1, remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No mechanistic link established between intracellular myo-inositol levels and p21/ZEB-1 or growth control","No structural model of the mammalian enzyme in the corpus","Nuclear positioning/memory not tested for human ISYNA1"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016853","term_label":"isomerase activity","supporting_discovery_ids":[0,19]},{"term_id":"GO:0016740","term_label":"transferase activity","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[17,21]},{"term_id":"GO:0005635","term_label":"nuclear envelope","supporting_discovery_ids":[17]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0,25]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[1,3,4,22]},{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[21,27]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[25,26]}],"complexes":[],"partners":["INO2","INO4","CBF1","P53","MSI2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9NPH2","full_name":"Inositol-3-phosphate synthase 1","aliases":["Myo-inositol 1-phosphate synthase","MI-1-P synthase","MIP synthase","hIPS","Myo-inositol 1-phosphate synthase A1","hINO1"],"length_aa":558,"mass_kda":61.1,"function":"Key enzyme in myo-inositol biosynthesis pathway that catalyzes the conversion of glucose 6-phosphate to 1-myo-inositol 1-phosphate in a NAD-dependent manner (PubMed:15024000, PubMed:23902760). 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N.J.)","url":"https://pubmed.ncbi.nlm.nih.gov/25687301","citation_count":19,"is_preprint":false},{"pmid":"35579426","id":"PMC_35579426","title":"Mitotically heritable, RNA polymerase II-independent H3K4 dimethylation stimulates INO1 transcriptional memory.","date":"2022","source":"eLife","url":"https://pubmed.ncbi.nlm.nih.gov/35579426","citation_count":18,"is_preprint":false},{"pmid":"7975896","id":"PMC_7975896","title":"Comparison of INO1 gene sequences and products in Candida albicans and Saccharomyces cerevisiae.","date":"1994","source":"Yeast (Chichester, England)","url":"https://pubmed.ncbi.nlm.nih.gov/7975896","citation_count":18,"is_preprint":false},{"pmid":"21841945","id":"PMC_21841945","title":"Differential methylation of the gene encoding myo-inositol 3-phosphate synthase (Isyna1) in rat tissues.","date":"2011","source":"Epigenomics","url":"https://pubmed.ncbi.nlm.nih.gov/21841945","citation_count":18,"is_preprint":false},{"pmid":"11840310","id":"PMC_11840310","title":"Epi-inositol regulates expression of the yeast INO1 gene encoding inositol-1-P synthase.","date":"2002","source":"Molecular psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/11840310","citation_count":18,"is_preprint":false},{"pmid":"10224245","id":"PMC_10224245","title":"The REG1 gene product is required for repression of INO1 and other inositol-sensitive upstream activating sequence-containing genes of yeast.","date":"1999","source":"Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/10224245","citation_count":18,"is_preprint":false},{"pmid":"26688804","id":"PMC_26688804","title":"INO1 transcriptional memory leads to DNA zip code-dependent interchromosomal clustering.","date":"2015","source":"Microbial cell (Graz, Austria)","url":"https://pubmed.ncbi.nlm.nih.gov/26688804","citation_count":18,"is_preprint":false},{"pmid":"31619750","id":"PMC_31619750","title":"Expression regulation of myo-inositol 3-phosphate synthase 1 (INO1) in determination of phytic acid accumulation in rice grain.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/31619750","citation_count":17,"is_preprint":false},{"pmid":"24267275","id":"PMC_24267275","title":"Clinical grade iPS cells: need for versatile small molecules and optimal cell sources.","date":"2013","source":"Chemistry & biology","url":"https://pubmed.ncbi.nlm.nih.gov/24267275","citation_count":17,"is_preprint":false},{"pmid":"28758131","id":"PMC_28758131","title":"Treatment of Diabetes Mellitus Using iPS Cells and Spice Polyphenols.","date":"2017","source":"Journal of diabetes research","url":"https://pubmed.ncbi.nlm.nih.gov/28758131","citation_count":17,"is_preprint":false},{"pmid":"33810153","id":"PMC_33810153","title":"A ROCK Inhibitor Promotes Graft Survival during Transplantation of iPS-Cell-Derived Retinal Cells.","date":"2021","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/33810153","citation_count":17,"is_preprint":false},{"pmid":"20935143","id":"PMC_20935143","title":"Derepression of INO1 transcription requires cooperation between the Ino2p-Ino4p heterodimer and Cbf1p and recruitment of the ISW2 chromatin-remodeling complex.","date":"2010","source":"Eukaryotic cell","url":"https://pubmed.ncbi.nlm.nih.gov/20935143","citation_count":16,"is_preprint":false},{"pmid":"21373884","id":"PMC_21373884","title":"DNA methylation assay for X-chromosome inactivation in female human iPS cells.","date":"2011","source":"Stem cell reviews and reports","url":"https://pubmed.ncbi.nlm.nih.gov/21373884","citation_count":16,"is_preprint":false},{"pmid":"33005258","id":"PMC_33005258","title":"Strategies for immune regulation in iPS cell-based cardiac regenerative medicine.","date":"2020","source":"Inflammation and regeneration","url":"https://pubmed.ncbi.nlm.nih.gov/33005258","citation_count":16,"is_preprint":false},{"pmid":"22009222","id":"PMC_22009222","title":"Recurrent trisomy and Robertsonian translocation of chromosome 14 in murine iPS cell lines.","date":"2011","source":"Chromosome research : an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology","url":"https://pubmed.ncbi.nlm.nih.gov/22009222","citation_count":16,"is_preprint":false},{"pmid":"33292717","id":"PMC_33292717","title":"Ex vivo generation of platelet products from human iPS cells.","date":"2020","source":"Inflammation and regeneration","url":"https://pubmed.ncbi.nlm.nih.gov/33292717","citation_count":15,"is_preprint":false},{"pmid":"7753636","id":"PMC_7753636","title":"INO1-100: an allele of the Saccharomyces cerevisiae INO1 gene that is transcribed without the action of the positive factors encoded by the INO2, INO4, SWI1, SWI2 and SWI3 genes.","date":"1995","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/7753636","citation_count":15,"is_preprint":false},{"pmid":"23264997","id":"PMC_23264997","title":"Generation of clinically relevant \"induced pluripotent stem\" (iPS) cells.","date":"2011","source":"Journal of stem cells","url":"https://pubmed.ncbi.nlm.nih.gov/23264997","citation_count":15,"is_preprint":false},{"pmid":"27572712","id":"PMC_27572712","title":"Induced Pluripotent Stem (iPS) Cells in Dentistry: A Review.","date":"2016","source":"International journal of stem cells","url":"https://pubmed.ncbi.nlm.nih.gov/27572712","citation_count":15,"is_preprint":false},{"pmid":"34808354","id":"PMC_34808354","title":"Metabolomics and transcriptomics of pheromone biosynthesis in an aggressive forest pest Ips typographus.","date":"2021","source":"Insect biochemistry and molecular biology","url":"https://pubmed.ncbi.nlm.nih.gov/34808354","citation_count":15,"is_preprint":false},{"pmid":"23823661","id":"PMC_23823661","title":"Induced pluripotent stem (iPS) cells from human fetal stem cells (hFSCs).","date":"2013","source":"Organogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/23823661","citation_count":15,"is_preprint":false},{"pmid":"36626080","id":"PMC_36626080","title":"Progress of iPS cell-based transplantation therapy for retinal diseases.","date":"2023","source":"Japanese journal of ophthalmology","url":"https://pubmed.ncbi.nlm.nih.gov/36626080","citation_count":14,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":42851,"output_tokens":7846,"usd":0.123121,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":16710,"output_tokens":3942,"usd":0.09105,"stage2_stop_reason":"end_turn"},"total_usd":0.214171,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"Looking through the papers, I need to identify those about the canonical ISYNA1 protein (myo-inositol-3-phosphate synthase / inositol-1-phosphate synthase). The HGNC aliases include Ino1 and IPS.\n\nMost papers in this corpus are about iPS (induced pluripotent stem) cells — a completely different topic. The relevant papers are those about the yeast INO1 gene (ortholog of ISYNA1, encoding inositol-1-phosphate synthase) and the mammalian ISYNA1 gene directly.\n\nLet me identify the on-target papers:\n- Papers about yeast INO1 (ortholog): PMIDs 15455074, 3025587, 8195172, 2027776, 9252414, 8810347, 11278273, 15371354, 12242221, 1587797, 10747047, 15716495, 10224244, 12761300, 11489850, 6374665, 17249096, 20932479, 8537323, 11486011, 8810039, 7753636, 20935143, 35579426, 26688804\n- Papers about mammalian ISYNA1 directly: PMIDs 27035231, 32779876, 21841945\n- Paper about M. tuberculosis ino1 (PMID 14763976) — symbol collision in bacteria, functionally related but not the mammalian ortholog. However it does describe active site mutagenesis of inositol-1-phosphate synthase.\n- Rice INO1 (PMID 31619750) — plant ortholog, symbol collision in different kingdom context.\n\nThe M. tuberculosis paper (14763976) describes active site mutagenesis relevant to the enzyme mechanism. I'll include it with appropriate confidence noting it's a bacterial enzyme.\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1984,\n      \"finding\": \"The yeast INO1 gene (ortholog of ISYNA1) encodes myo-inositol-1-phosphate synthase, the enzyme catalyzing the first committed step in inositol biosynthesis; the cloned gene complemented ino1 loss-of-function mutants and restored cross-reactive enzyme protein, confirming its identity as the structural gene for inositol-1-phosphate synthase.\",\n      \"method\": \"Genetic complementation of ino1 auxotrophs with cloned DNA; antibody cross-reactivity assay for enzyme protein; Southern blot confirming unique genomic locus\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct enzymatic complementation plus immunological confirmation, foundational cloning paper replicated by subsequent studies\",\n      \"pmids\": [\"6374665\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1986,\n      \"finding\": \"INO1 (ISYNA1 ortholog) expression and inositol-1-phosphate synthase activity are transcriptionally repressed 12-fold by exogenous inositol and 33-fold by inositol plus choline combined; repression requires regulatory genes INO2 and INO4 (loss-of-function causes auxotrophy), and constitutive overexpression occurs in opi1 mutants.\",\n      \"method\": \"RNA blot hybridization under defined growth conditions; enzyme activity assays; genetic analysis of ino2, ino4, opi1 mutants\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (RNA blot, enzyme assay, genetics), replicated across many subsequent studies\",\n      \"pmids\": [\"3025587\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1981,\n      \"finding\": \"The INO1 locus (structural gene for inositol-1-phosphate synthase) was mapped to chromosome X of S. cerevisiae between ura2 and cdc6; ~70% of inositol auxotrophs carry ino1 alleles, and INO1 null mutations are not suppressible by known nonsense suppressors, suggesting premature termination is lethal.\",\n      \"method\": \"Trisomic analysis, genetic complementation, chromosomal mapping\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — classical genetics with multiple alleles and mapping, single lab\",\n      \"pmids\": [\"17249096\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1991,\n      \"finding\": \"A 9-bp repeated element (consensus 5'-CATGTGAAAT-3'), termed UAS(INO), in the INO1 promoter is necessary and sufficient for inositol/choline-responsive transcriptional regulation; the smallest active fragment was 40 bp containing one copy of this element.\",\n      \"method\": \"INO1 promoter-lacZ fusions with systematic deletions and oligonucleotide insertions; beta-galactosidase reporter assays\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — promoter dissection with multiple deletion constructs and heterologous reporter, mechanistic element defined\",\n      \"pmids\": [\"2027776\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"The positive regulators Ino2p and Ino4p (both bHLH proteins) form a heterodimeric complex that binds to the INO1 promoter UAS(INO) element; neither protein alone binds DNA, and the complex is identical in mobility to that formed with whole-cell extracts.\",\n      \"method\": \"In vitro translation of Ino2p and Ino4p; electrophoretic mobility shift assay (EMSA); immunoprecipitation confirming Ino2p–Ino4p protein–protein interaction in absence of DNA; competition with bHLH consensus oligonucleotide\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstitution in vitro with purified translated proteins, EMSA, immunoprecipitation, multiple orthogonal methods in one study\",\n      \"pmids\": [\"8195172\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"A dominant CSE1 mutation causes choline-dependent repression of INO1 (ISYNA1 ortholog) and inositol-1-phosphate synthase; choline-dependent repression requires metabolism of choline via the CDP-choline pathway, as blocking this pathway abolishes choline-induced INO1 repression.\",\n      \"method\": \"INO1-lacZ promoter fusions; Northern blot; enzyme activity assay; genetic epistasis with CDP-choline pathway mutations\",\n      \"journal\": \"Journal of biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reporter fusions plus epistasis analysis, single lab\",\n      \"pmids\": [\"1587797\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"The SCS2 gene (encoding an integral membrane protein, VAP homolog) is a multicopy suppressor of ire15 and CSE1 mutations affecting INO1 expression; SCS2 and INO2/SCS1 (a positive regulator) both suppress these regulatory mutations, placing Scs2p in the INO1 regulatory pathway.\",\n      \"method\": \"Multicopy suppressor screen; genetic complementation; sequence analysis\",\n      \"journal\": \"Journal of biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic suppressor screen with complementation, single lab\",\n      \"pmids\": [\"8537323\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Repression of INO1 transcription in response to inositol requires ongoing phosphatidylcholine (PC) biosynthesis but is independent of the specific pathway (methylation vs. CDP-choline) used for PC synthesis; intermediates in these pathways are not the regulatory signal, and repression correlates with the rate of PC synthesis sustaining growth rather than absolute PC proportion.\",\n      \"method\": \"INO1-lacZ reporter assays; genetic analysis of PC biosynthesis mutants (cho2, opi3, cki1, pct1); growth and phospholipid measurements\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple genetic backgrounds tested with reporter assay, single lab\",\n      \"pmids\": [\"8810347\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Individual UAS(INO) elements in the INO1 promoter differ in functionality; most native INO1 promoter elements are inactive individually, whereas all CHO2 promoter elements are active, explaining differential regulation between co-regulated genes; elements with C or A at the 5' position of the consensus are functional.\",\n      \"method\": \"Systematic placement of individual promoter fragments upstream of CYC1-lacZ reporter; beta-galactosidase assay; oligonucleotide mutagenesis of consensus first position\",\n      \"journal\": \"Yeast (Chichester, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — promoter mutagenesis with reporter assay, single lab, mechanistic detail on cis-element function\",\n      \"pmids\": [\"8810039\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Inactivation of Sec14p (phosphatidylinositol/phosphatidylcholine transfer protein) in a cki1 background leads to increased phosphatidylcholine turnover via a phospholipase D-like mechanism, which derepresses INO1 (ISYNA1 ortholog) transcription, establishing a regulatory link between PC turnover and INO1 expression.\",\n      \"method\": \"Genetic epistasis (sec14ts cki1 double mutants); choline excretion assay; INO1-lacZ reporter; enzyme assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with reporter assay, single lab\",\n      \"pmids\": [\"9252414\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"The REG1-encoded regulatory subunit of the Glc7 phosphatase is required for repression of INO1; reg1 loss-of-function suppresses inositol auxotrophy of ino4 and ino2 missense mutants and causes constitutive INO1 expression, placing Reg1p/Glc7 phosphatase activity as a positive component of INO1 repression. Separately, Snf4/Snf1 kinase activity promotes INO1 activation, as dominant SNF4 mutations suppress INO1 derepression defects.\",\n      \"method\": \"Genetic suppressor screen; INO1-lacZ reporter assays; two-hybrid interaction assay for Snf4-Snf1 interaction\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic suppressor screen with reporter confirmation, single lab\",\n      \"pmids\": [\"10224244\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"REG1 (Glc7 phosphatase regulatory subunit) loss-of-function causes constitutive INO1 expression independently of OPI1; REG1 suppresses ino4 missense alleles but not ino2/ino4 null mutations; OPI1 protein does not bind UAS(INO) or interact with Ino2p or Ino4p directly.\",\n      \"method\": \"INO1-lacZ reporter assays in multiple mutant backgrounds; two-hybrid assays testing Opi1p-UAS(INO), Opi1p-Ino2p, Opi1p-Ino4p interactions (all negative)\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple genetic backgrounds with reporter assay; negative two-hybrid results are informative; single lab\",\n      \"pmids\": [\"10747047\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Both lithium and valproate decrease intracellular myo-inositol levels and increase expression of INO1 (ISYNA1 ortholog) and INO2; valproate may inhibit Ino1p-catalyzed synthesis of inositol-1-phosphate directly, as valproate treatment decreases inositol monophosphate synthesis; the opi1 mutant is more resistant to lithium (but not valproate) growth inhibition, indicating different mechanisms for the two drugs.\",\n      \"method\": \"Northern blot for INO1/INO2 mRNA; inositol mass measurement; inositol monophosphate synthesis assay; growth assays in opi1 mutant\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — biochemical assays plus genetics in yeast, single lab\",\n      \"pmids\": [\"11278273\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The Snf1 kinase is required for INO1 activation; mutations in ACC1 (acetyl-CoA carboxylase) and FAS1 (fatty acid synthase beta subunit) suppress the inositol auxotrophy of snf1Δ strains by reducing Acc1 activity, which is elevated in snf1Δ cells because Snf1 normally phosphorylates and inactivates Acc1p; reduced fatty acid synthesis rate restores INO1 expression.\",\n      \"method\": \"Genetic suppressor screen; in vitro Acc1 enzyme activity assay; soraphen A (Acc1 inhibitor) growth sensitivity; INO1-lacZ reporter; conditional ACC1 expression\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple orthogonal methods (genetics, in vitro enzyme assay, chemical inhibitor, conditional expression) establishing Snf1→Acc1→INO1 pathway\",\n      \"pmids\": [\"11486011\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The Isw2p-Itc1p chromatin-remodeling complex represses INO1 expression; deletion of either ISW2 or ITC1 in a hac1Δ background derepresses INO1 even under inositol-repressing conditions; a truncated dominant-negative form of Itc1p suppresses the hac1Δ inositol auxotrophy by impairing Isw2p-Itc1p repressor function.\",\n      \"method\": \"Multicopy suppressor screen; INO1-lacZ reporter; genetic epistasis (isw2Δ itc1Δ hac1Δ); dominant-negative truncation analysis\",\n      \"journal\": \"Journal of bacteriology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reporter assays with genetic epistasis and dominant-negative construct, single lab\",\n      \"pmids\": [\"11489850\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The unfolded protein response (UPR) pathway (Ire1p/Hac1p) is required for sustained high-level INO1 expression under inositol starvation but not for transient derepression; inactivation of Sec14p activates the UPR; the UPR is not required for INO1 regulation in the sec14ts cki1Δ background.\",\n      \"method\": \"Genetic epistasis (ire1Δ, hac1Δ combined with sec14ts cki1Δ); INO1-lacZ reporter; UPR reporter assays\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with reporter assays, single lab\",\n      \"pmids\": [\"12242221\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Scs2p (yeast VAP homolog) regulates INO1 expression by controlling phosphatidylcholine synthesis through the CDP-choline pathway; scs2Δ cells have reduced INO1 mRNA but normal INO1 promoter-driven reporter activity, suggesting Scs2p acts post-transcriptionally or on mRNA stability; disruption of CDP-choline pathway genes rescues INO1 expression defect in scs2Δ cells.\",\n      \"method\": \"INO1 mRNA Northern blot; INO1 promoter-lacZ reporter; phospholipid composition analysis; genetic epistasis with CDP-choline pathway mutants\",\n      \"journal\": \"Journal of biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple assays (Northern, reporter, lipidomics, genetics) in single lab\",\n      \"pmids\": [\"12761300\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Activation of INO1 (ISYNA1 ortholog) recruits the gene locus to the nuclear periphery; repressed INO1 is distributed throughout the nucleoplasm; recruitment requires the transcriptional activator Hac1p (produced upon UPR induction) and the integral membrane protein Scs2p (which antagonizes Opi1p repressor); artificial tethering of INO1 to the nuclear membrane enables activation in the absence of Scs2p.\",\n      \"method\": \"Fluorescence microscopy of GFP-tagged INO1 locus; genetic analysis of hac1Δ, scs2Δ, opi1Δ; artificial membrane tethering experiment\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct live imaging of locus position, multiple genetic backgrounds, and functional rescue by artificial tethering — multiple orthogonal methods\",\n      \"pmids\": [\"15455074\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"The UPR pathway plays a functional role in membrane trafficking under secretory stress; UPR loss-of-function (hac1Δ, ire1Δ) exacerbates secretory defects and slows vacuolar protein transport; high UPR induction under secretory stress does not correlate with elevated INO1 expression, indicating UPR and INO1 regulatory signals are separable.\",\n      \"method\": \"Carboxypeptidase Y transit time assay; genetic interaction analysis (Sec– mutations with ire1Δ/hac1Δ); INO1-lacZ reporter; UPR reporter\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple genetic backgrounds with biochemical trafficking assay and reporter, single lab\",\n      \"pmids\": [\"15371354\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"In Mycobacterium tuberculosis, four active-site residues of inositol-1-phosphate synthase (Ino1, homolog of ISYNA1) are essential for enzymatic activity; site-directed mutagenesis of these residues abolished activity; a D310N mutation caused loss of the active-site Zn²⁺ ion and a conformational change in the NAD⁺ cofactor; the ino1 gene is essential for mycobacterial growth and virulence.\",\n      \"method\": \"Site-directed mutagenesis of four active-site residues; enzyme activity assay; metal ion analysis; NAD⁺ cofactor conformational assessment; conditional knockout in macrophages and SCID mice\",\n      \"journal\": \"Molecular microbiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstitution with mutagenesis and cofactor analysis, but bacterial enzyme not the mammalian protein\",\n      \"pmids\": [\"14763976\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Snf1 kinase and Sit4 phosphatase have opposing roles in INO1 transcription: Snf1 promotes activation while Sit4 represses it; both regulate binding of TATA-binding protein (TBP) to the INO1 promoter as shown by chromatin immunoprecipitation; sit4 mutation suppresses snf1Δ inositol auxotrophy; TOR signaling (via rapamycin) reduces INO1 activation through Sit4.\",\n      \"method\": \"Chromatin immunoprecipitation (ChIP) for TBP at INO1 promoter; genetic suppressor analysis; rapamycin treatment; INO1-lacZ reporter\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP assay directly showing TBP recruitment, plus genetic epistasis and pharmacological intervention, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"15716495\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Interaction of a DNA 'zip code' (11-bp memory recruitment sequence, MRS) in the INO1 promoter with the nuclear pore complex (NPC) protein Nup100 controls both peripheral targeting of recently repressed INO1 and incorporation of histone variant H2A.Z; loss of MRS or Nup100 abolishes INO1 transcriptional memory, leading to nucleoplasmic localization and slower reactivation.\",\n      \"method\": \"Fluorescence microscopy of INO1 locus position; H2A.Z chromatin immunoprecipitation; promoter MRS deletion analysis; nup100Δ genetic analysis; reactivation kinetics assay\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct locus imaging, ChIP for histone variant, promoter deletion, and functional reactivation kinetics — multiple orthogonal methods\",\n      \"pmids\": [\"20932479\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Complete derepression of INO1 transcription requires cooperative binding of both the Ino2p-Ino4p bHLH heterodimer to UAS(INO) sites in the INO1 promoter and Cbf1p binding to distal sites encompassing the upstream SNA3 ORF; Cbf1p binding requires prior Ino2p-Ino4p binding and vice versa; Cbf1p binding is required for recruitment of the ISW2 chromatin-remodeling complex to UAS(INO) sites.\",\n      \"method\": \"Chromatin immunoprecipitation (ChIP) for Cbf1p, Ino2p, Ino4p, and ISW2 at INO1 promoter; INO1-lacZ reporter in cbf1Δ, ino2Δ, ino4Δ, isw2Δ mutants\",\n      \"journal\": \"Eukaryotic cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP for multiple factors with genetic epistasis and reporter assay, cooperative binding mechanism defined\",\n      \"pmids\": [\"20935143\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Rat Isyna1 (myo-inositol-3-phosphate synthase gene) is regulated by DNA methylation in a tissue-specific manner; in vitro methylation of the promoter suppresses transcription; a specific CpG residue in the -700 to -500 bp region is required for promoter activity in neuronal cells; a tissue-specific differentially methylated region (T-DMR) between +450 and +650 bp correlates inversely with mRNA levels across tissues.\",\n      \"method\": \"Transfection with in vitro methylated promoter constructs; Southern blot with methylation-sensitive restriction enzyme; CpG methylation profiling; CpG mutation analysis by transfection\",\n      \"journal\": \"Epigenomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro methylation/transfection assay with mutagenesis of specific CpG, single lab\",\n      \"pmids\": [\"21841945\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"INO1 transcriptional memory involves interchromosomal clustering: during memory, both alleles of INO1 cluster together in diploids, and endogenous INO1 clusters with an ectopic copy in haploids; memory clustering requires Nup100 and two sets of DNA zip codes (those for active targeting and those for memory targeting); clustering is cell cycle-regulated during memory but peripheral localization is not.\",\n      \"method\": \"Fluorescence microscopy of tagged INO1 loci in diploid and haploid cells; genetic analysis of nup100Δ and zip code mutations; cell cycle staging\",\n      \"journal\": \"Microbial cell (Graz, Austria)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct locus imaging in multiple genetic backgrounds, single lab\",\n      \"pmids\": [\"26688804\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Human ISYNA1 (inositol-3-phosphate synthase) is a direct transcriptional target of p53; p53 activates ISYNA1 expression through a p53 response element in the seventh exon; ectopic ISYNA1 expression increases intracellular myo-inositol levels and suppresses tumor cell growth; ISYNA1 knockdown causes resistance to adriamycin treatment, placing ISYNA1 downstream of p53 in growth suppression.\",\n      \"method\": \"Microarray screening followed by p53 induction; chromatin immunoprecipitation for p53 at ISYNA1 response element; myo-inositol measurement after ISYNA1 overexpression; cell proliferation assay; siRNA knockdown with drug treatment\",\n      \"journal\": \"International journal of oncology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP identifying p53 response element, functional myo-inositol measurement, KD/OE with defined phenotype, multiple orthogonal methods in single lab\",\n      \"pmids\": [\"27035231\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ISYNA1 acts as a tumor suppressor downstream of MSI2 (Musashi2) in pancreatic cancer; MSI2 represses ISYNA1 expression (dependent on wild-type p53); ISYNA1 silencing promotes cell proliferation and cell cycle progression by inhibiting p21, and enhances migration/invasion by upregulating ZEB-1; MSI2 silencing-induced suppression of migration is rescued by ISYNA1 knockdown, defining an MSI2→ISYNA1→p21/ZEB-1 pathway.\",\n      \"method\": \"siRNA knockdown and overexpression of ISYNA1 and MSI2; cell proliferation and cell cycle assays; migration/invasion assays; Western blot for p21 and ZEB-1; rescue experiments\",\n      \"journal\": \"Journal of cellular and molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis by rescue experiment, multiple cellular phenotype readouts, single lab\",\n      \"pmids\": [\"32779876\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"INO1 transcriptional memory involves RNAPII-independent H3K4 dimethylation (H3K4me2) that is mitotically heritable; H3K4me2 at the INO1 locus requires Nup100, SET3C, and the Leo1 subunit of the Paf1 complex, but not RNAPII; upon loss of an essential transcription factor, this H3K4me2 is inherited through multiple cell cycles; COMPASS (the H3K4 methyltransferase) physically interacts with SET3C (the potential H3K4me2 reader), suggesting a spreading/re-incorporation mechanism.\",\n      \"method\": \"ChIP for H3K4me2 after RNAPII depletion; genetic analysis of nup100Δ, set3c, leo1Δ mutants; cell cycle tracking of histone mark inheritance; co-immunoprecipitation of COMPASS and SET3C\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP, genetic epistasis, protein interaction (Co-IP), and cell-cycle inheritance assay — multiple orthogonal methods in single study\",\n      \"pmids\": [\"35579426\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ISYNA1 encodes myo-inositol-3-phosphate synthase (inositol-1-phosphate synthase), the rate-limiting enzyme catalyzing the first committed step in myo-inositol biosynthesis from glucose-6-phosphate; in yeast (INO1 ortholog) its transcription is tightly regulated by phospholipid metabolic status through a UAS(INO) promoter element bound by the Ino2p-Ino4p bHLH heterodimer and repressed by Opi1p, with additional control by the Snf1 kinase/Sit4 phosphatase balance affecting TBP recruitment, the Isw2p-Itc1p chromatin remodeling complex, and NPC-mediated gene positioning that confers epigenetic transcriptional memory via RNAPII-independent H3K4me2; in mammalian cells, human ISYNA1 is a direct p53 transcriptional target that increases intracellular myo-inositol to suppress tumor cell growth, and its expression is also regulated by tissue-specific DNA methylation and suppressed by MSI2 to promote cancer progression via a ISYNA1–p21/ZEB-1 axis.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"ISYNA1 (and its yeast ortholog INO1) encodes myo-inositol-3-phosphate synthase, the enzyme catalyzing the first committed, rate-limiting step of myo-inositol biosynthesis [#0]. Active-site mutagenesis of the homologous enzyme establishes that catalysis depends on a defined set of active-site residues, a bound Zn²⁺ ion, and an NAD⁺ cofactor [#19]. In yeast, INO1 has served as a paradigm for transcriptional control coupled to lipid metabolism: its expression is repressed by inositol and choline and depends on the positive regulators Ino2p and Ino4p, two bHLH proteins that heterodimerize and bind the UAS(INO) promoter element, while neither binds DNA alone [#1, #4, #3]. Full derepression additionally requires cooperative Cbf1p binding at distal sites and recruitment of the Isw2p-Itc1p chromatin-remodeling complex [#22, #14]. The repressing signal is the rate of phosphatidylcholine biosynthesis rather than any specific pathway intermediate, linking INO1 output to membrane phospholipid flux [#7, #9]. INO1 transcription is further tuned by opposing Snf1 kinase and Sit4/Glc7 phosphatase activities that control TBP recruitment to the promoter, with Snf1 acting in part through phosphoinactivation of Acc1p [#20, #13, #10]. The locus is a model for nuclear-position-dependent gene regulation: activation recruits INO1 to the nuclear periphery via Scs2p and the activator Hac1p [#17], and a promoter DNA 'zip code' interacting with the nucleoporin Nup100 confers mitotically heritable transcriptional memory through interchromosomal clustering, H2A.Z incorporation, and RNAPII-independent H3K4me2 deposited via SET3C, Leo1/Paf1, and COMPASS [#21, #24, #27]. In mammalian cells, human ISYNA1 is a direct p53 transcriptional target whose induction raises intracellular myo-inositol and suppresses tumor cell growth [#25], and it acts as a tumor suppressor downstream of MSI2 through an ISYNA1→p21/ZEB-1 axis, with its expression also controlled by tissue-specific DNA methylation [#26, #23].\",\n  \"teleology\": [\n    {\n      \"year\": 1984,\n      \"claim\": \"Established the molecular identity of the gene by showing it is the structural gene for the inositol biosynthetic enzyme, anchoring all downstream mechanistic work.\",\n      \"evidence\": \"Genetic complementation of ino1 auxotrophs with cloned DNA plus immunological detection of enzyme protein in yeast\",\n      \"pmids\": [\"6374665\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not resolve enzyme catalytic mechanism or cofactor requirements\", \"Mammalian ortholog function not addressed\"]\n    },\n    {\n      \"year\": 1986,\n      \"claim\": \"Defined the gene as inositol/choline-repressible and identified the trans-acting regulators (INO2, INO4 positive; OPI1 negative) that control its expression.\",\n      \"evidence\": \"RNA blot, enzyme activity assays, and genetic analysis of ino2/ino4/opi1 mutants in yeast\",\n      \"pmids\": [\"3025587\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the cis-element bound by regulators\", \"Molecular nature of the repressing signal unknown\"]\n    },\n    {\n      \"year\": 1991,\n      \"claim\": \"Mapped regulation to a discrete promoter element, showing a single UAS(INO) repeat is necessary and sufficient for inositol/choline-responsive control.\",\n      \"evidence\": \"Promoter-lacZ deletion/insertion reporter dissection in yeast\",\n      \"pmids\": [\"2027776\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the protein binding the element\", \"Differential activity among individual elements not yet resolved\"]\n    },\n    {\n      \"year\": 1994,\n      \"claim\": \"Demonstrated the mechanistic basis of positive regulation: Ino2p and Ino4p heterodimerize and only the complex binds UAS(INO).\",\n      \"evidence\": \"In vitro translation, EMSA, and co-immunoprecipitation of Ino2p-Ino4p in yeast\",\n      \"pmids\": [\"8195172\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not address how the repressor counteracts this complex\", \"Chromatin context of binding not examined\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Resolved the nature of the repressing signal, showing repression tracks the rate of phosphatidylcholine biosynthesis rather than any specific pathway or intermediate.\",\n      \"evidence\": \"Reporter assays across PC biosynthesis mutants with phospholipid measurements in yeast\",\n      \"pmids\": [\"8810347\", \"8810039\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not identify the molecular sensor transducing PC flux to the promoter\", \"Did not connect signal to OPI1 mechanism\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Identified opposing kinase/phosphatase and metabolic inputs (Snf1, Acc1, Reg1/Glc7) that set the activation threshold, integrating energy and fatty-acid metabolism with inositol gene control.\",\n      \"evidence\": \"Genetic suppressor screens, in vitro Acc1 enzyme assays, chemical inhibition, and reporters in yeast\",\n      \"pmids\": [\"11486011\", \"10224244\", \"10747047\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not show direct promoter-level mechanism of Snf1/Sit4 action\", \"Mammalian relevance untested\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Showed how kinase/phosphatase balance acts mechanistically at the promoter by controlling TBP recruitment, linking TOR signaling to inositol gene transcription.\",\n      \"evidence\": \"ChIP for TBP, genetic epistasis, and rapamycin treatment in yeast\",\n      \"pmids\": [\"15716495\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define the chromatin steps downstream of TBP recruitment\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Defined cooperative activation requiring both the Ino2p-Ino4p heterodimer and Cbf1p, with Cbf1p directing ISW2 chromatin remodeler recruitment.\",\n      \"evidence\": \"ChIP for multiple factors with genetic epistasis and reporter assays in yeast\",\n      \"pmids\": [\"20935143\", \"11489850\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Order of remodeling and transcription factor loading not fully resolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Established the gene as a model for spatial and epigenetic transcriptional memory, linking promoter zip codes and the nuclear pore to histone variant deposition and faster reactivation.\",\n      \"evidence\": \"Locus imaging, H2A.Z ChIP, promoter MRS deletion, and nup100Δ analysis in yeast\",\n      \"pmids\": [\"20932479\", \"15455074\", \"26688804\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism connecting NPC contact to histone variant incorporation incomplete\", \"Conservation of positioning memory in mammals untested\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Connected the gene to mammalian tumor suppression by establishing human ISYNA1 as a direct p53 target whose myo-inositol output restrains cell growth.\",\n      \"evidence\": \"p53 ChIP at a response element, myo-inositol measurement, and knockdown/overexpression with drug response in human cells\",\n      \"pmids\": [\"27035231\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which elevated myo-inositol suppresses growth not defined\", \"Did not address upstream regulators of ISYNA1 in cancer\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Placed ISYNA1 in an oncogenic regulatory circuit as a p53-dependent target repressed by MSI2, acting through p21 and ZEB-1 to control proliferation and invasion.\",\n      \"evidence\": \"Knockdown/overexpression of ISYNA1 and MSI2, phenotypic assays, and rescue experiments in pancreatic cancer cells\",\n      \"pmids\": [\"32779876\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct biochemical link between ISYNA1 enzymatic output and p21/ZEB-1 regulation unresolved\", \"Single-lab cellular study without in vivo validation\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Refined the chromatin basis of transcriptional memory by showing RNAPII-independent, mitotically heritable H3K4me2 deposited via SET3C, Leo1/Paf1, and COMPASS.\",\n      \"evidence\": \"ChIP after RNAPII depletion, genetic epistasis, cell-cycle inheritance tracking, and COMPASS-SET3C co-IP in yeast\",\n      \"pmids\": [\"35579426\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Reader-to-methyltransferase spreading mechanism inferred, not directly reconstituted\", \"Relevance to mammalian ISYNA1 unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the enzymatic product myo-inositol mechanistically drives mammalian growth suppression, and whether the yeast nuclear-memory paradigm operates at human ISYNA1, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No mechanistic link established between intracellular myo-inositol levels and p21/ZEB-1 or growth control\", \"No structural model of the mammalian enzyme in the corpus\", \"Nuclear positioning/memory not tested for human ISYNA1\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016853\", \"supporting_discovery_ids\": [0, 19]},\n      {\"term_id\": \"GO:0016740\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [17, 21]},\n      {\"term_id\": \"GO:0005635\", \"supporting_discovery_ids\": [17]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 25]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [1, 3, 4, 22]},\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [21, 27]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [25, 26]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"INO2\", \"INO4\", \"CBF1\", \"p53\", \"MSI2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}