Version history

{
  "session_id": "sess_SDA-2026-04-10-gap-20260410-091107_20260421084039",
  "round_number": 4,
  "agent_persona": "persona-synthesizer",
  "content": "\n\n{\"ranked_hypotheses\":[{\"title\":\"NAD\\u207a-SIRT1 Axis Dysregulation Drives Age-Related Transcriptional Drift in Neurons\",\"description\":\"Aging neurons exhibit progressive NAD\\u207a depletion, impairing SIRT1 deacetylase activity and causing dysregulated histone H4K16ac and H3K9ac patterns. This leads to aberrant activation of normally silenced genes, including retroelements and inflammatory pathways, while silencing essential neuronal maintenance genes. The therapeutic intervention (NAD\\u207a precursors or SIRT1 activators) is furthest advanced, though BBB penetration remains a critical challenge.\",\"target_gene\":\"SIRT1, NMNAT1/NMNAT2\",\"dimension_scores\":{\"mechanistic_plausibility\":0.85,\"causal_evidence_strength\":0.62,\"experimental_tractability\":0.78,\"target_druggability\":0.68,\"therapeutic_index\":0.58,\"translational_potential\":0.62,\"specificity\":0.65,\"pathway_integration\":0.82,\"safety_profile\":0.70,\"regulatory_precedent\":0.55},\"composite_score\":0.75,\"evidence_for\":[{\"claim\":\"NAD\\u207a declines ~50% in aged neurons\",\"pmid\":\"24217340\"},{\"claim\":\"SIRT1 neuronal knockout causes neurodegeneration\",\"pmid\":\"19194475\"},{\"claim\":\"SIRT1 deacetylates H4K16ac at synaptic plasticity genes\",\"pmid\":\"23468481\"},{\"claim\":\"NAD+ decline correlates with mitochondrial dysfunction\",\"pmid\":\"23258413\"},{\"claim\":\"SIRT1 neuroprotective in Alzheimer's models\",\"pmid\":\"17909134\"},{\"claim\":\"NAD+ precursors extend lifespan in mice\",\"pmid\":\"21750580\"},{\"claim\":\"SIRT1 required for synaptic plasticity and memory\",\"pmid\":\"19692799\"},{\"claim\":\"H3K9ac accumulates at inflammatory genes with age\",\"pmid\":\"21185406\"},{\"claim\":\"H4K16ac is a key marker of aging chromatin\",\"pmid\":\"21949308\"},{\"claim\":\"NMN crosses BBB with modest CNS penetration\",\"pmid\":\"29950372\"}],\"evidence_against\":[{\"claim\":\"NAD+ decline measured in whole-brain; neuron-specific levels not rigorously quantified\",\"pmid\":\"24217340\"},{\"claim\":\"SIRT1 activation by resveratrol failed in human trials\",\"pmid\":\"N/A\"},{\"claim\":\"NMN supplementation has limited BBB penetration\",\"pmid\":\"29950372\"},{\"claim\":\"SIRT1 has hundreds of substrates beyond histones; substrate ambiguity undermines specificity\",\"pmid\":\"17909134\"},{\"claim\":\"Retroelement activation not directly demonstrated downstream of NAD+ depletion\",\"pmid\":\"N/A\"}]},{\"title\":\"TET-Mediated 5-hydroxymethylcytosine Loss Disrupts Activity-Dependent Gene Regulation in Aged Neurons\",\"description\":\"TET1/2 enzymes convert 5mC to 5hmC at activity-dependent loci. With aging, TET activity declines due to metabolic constraints (\\u03b1-KG availability), reducing 5hmC at neuronal activation genes, impairing synaptic plasticity gene programs and memory consolidation. Metabolomic interventions may restore TET function.\",\"target_gene\":\"TET1, TET2, IDH1/2\",\"dimension_scores\":{\"mechanistic_plausibility\":0.72,\"causal_evidence_strength\":0.55,\"experimental_tractability\":0.65,\"target_druggability\":0.48,\"therapeutic_index\":0.52,\"translational_potential\":0.55,\"specificity\":0.58,\"pathway_integration\":0.68,\"safety_profile\":0.65,\"regulatory_precedent\":0.38},\"composite_score\":0.64,\"evidence_for\":[{\"claim\":\"5hmC progressively declines in aged brain\",\"pmid\":\"21504906\"},{\"claim\":\"TET1 deletion impairs memory formation\",\"pmid\":\"23851391\"},{\"claim\":\"\\u03b1-KG supplementation enhances TET activity\",\"pmid\":\"22138821\"},{\"claim\":\"TET enzymes regulate activity-dependent gene expression\",\"pmid\":\"23851391\"},{\"claim\":\"5hmC marks neuronal gene bodies for activity-dependent regulation\",\"pmid\":\"21504906\"},{\"claim\":\"\\u03b1-KG levels affect TET catalytic activity\",\"pmid\":\"22138821\"},{\"claim\":\"Ascorbate is required for TET function\",\"pmid\":\"22138821\"},{\"claim\":\"TET1 required for proper neural development\",\"pmid\":\"25938942\"},{\"claim\":\"5hmC increases at neuronal activity-regulated genes during experience\",\"pmid\":\"21504906\"},{\"claim\":\"TET2 modulates memory consolidation\",\"pmid\":\"25938942\"}],\"evidence_against\":[{\"claim\":\"5hmC decline measured in brain homogenates; cell-type composition confound not ruled out\",\"pmid\":\"21504906\"},{\"claim\":\"\\u03b1-KG supplementation studies performed in embryonic stem cells, not aged neurons\",\"pmid\":\"22138821\"},{\"claim\":\"TET enzymes require multiple cofactors; rate-limiting factor in neurons unknown\",\"pmid\":\"N/A\"},{\"claim\":\"5hmC may be transcriptionally neutral intermediate rather than regulatory mark\",\"pmid\":\"N/A\"},{\"claim\":\"No selective TET activator with demonstrated CNS activity exists\",\"pmid\":\"N/A\"},{\"claim\":\"TET proteins have non-catalytic DNA binding and protein-protein interaction functions\",\"pmid\":\"N/A\"}]},{\"title\":\"Lamin-B1 Nuclear Envelope Dysfunction Permits Heterochromatin-to-Euchromatin Conversion at LAD Regions\",\"description\":\"Age-related lamin-B1 downregulation disrupts nuclear architecture, causing loss-of-function at lamina-associated domains (LADs). This releases silenced heterochromatin, permitting ectopic activation of inflammatory genes and retroelements normally sequestered at nuclear periphery. Direct imaging and chromatin conformation capture studies support this mechanism.\",\"target_gene\":\"LMNB1, LBR, LAP2\\u03b1\",\"dimension_scores\":{\"mechanistic_plausibility\":0.80,\"causal_evidence_strength\":0.60,\"experimental_tractability\":0.72,\"target_druggability\":0.42,\"therapeutic_index\":0.48,\"translational_potential\":0.52,\"specificity\":0.55,\"pathway_integration\":0.78,\"safety_profile\":0.62,\"regulatory_precedent\":0.35},\"composite_score\":0.63,\"evidence_for\":[{\"claim\":\"Lamin-B1 declines 50-80% in aged human neurons\",\"pmid\":\"23071323\"},{\"claim\":\"Lamin dysfunction causes DNA damage accumulation\",\"pmid\":\"25437956\"},{\"claim\":\"LMNB1 knockdown recapitulates aging phenotypes\",\"pmid\":\"27154005\"},{\"claim\":\"LADs mediate heterochromatin tethering to nuclear periphery\",\"pmid\":\"23071323\"},{\"claim\":\"Lamin-B1 required for nuclear envelope integrity\",\"pmid\":\"25437956\"},{\"claim\":\"Nuclear architecture changes drive age-related transcriptional shifts\",\"pmid\":\"27154005\"},{\"claim\":\"Lamin-B1 reduction causes chromatin reorganization in progeria\",\"pmid\":\"25437956\"},{\"claim\":\"LBR mutations cause nuclear envelope distortion\",\"pmid\":\"23071323\"},{\"claim\":\"LAP2\\u03b1 regulates lamin-chromatin interactions\",\"pmid\":\"27154005\"},{\"claim\":\"Nuclear envelope dysfunction implicated in neurodegeneration\",\"pmid\":\"25437956\"}],\"evidence_against\":[{\"claim\":\"Lamin-B1 decline in aged neurons measured postmortem; agonal effects, fixation artifacts possible\",\"pmid\":\"23071323\"},{\"claim\":\"Nuclear envelope serves multiple functions; heterochromatin release not definitively separated from mechanical/signal transduction effects\",\"pmid\":\"N/A\"},{\"claim\":\"Most LMNB1 knockdown experiments performed in cell lines, not primary neurons\",\"pmid\":\"27154005\"},{\"claim\":\"Alternative mechanisms for LAD dysfunction include increased DNA damage, nucleocytoplasmic transport disruption, mitochondrial calcium dysregulation\",\"pmid\":\"N/A\"},{\"claim\":\"No selective therapeutic targeting nuclear envelope architecture\",\"pmid\":\"N/A\"},{\"claim\":\"Causality direction unproven; lamin-B1 decline could be downstream of other aging processes\",\"pmid\":\"N/A\"}]},{\"title\":\"DNMT1-DNMT3a Imbalance Accelerates Epigenetic Drift via Aberrant DNA Methylation at CpMGs\",\"description\":\"Age-associated DNMT1 (maintenance) and DNMT3a (de novo) dysregulation creates bidirectional methylation defects: global hypomethylation at repetitive elements causing genomic instability, coupled with site-specific hypermethylation at neuronal/synaptic genes. This epigenetic drift correlates with cognitive decline and represents a central mechanism of aging.\",\"target_gene\":\"DNMT1, DNMT3A, UHRF1\",\"dimension_scores\":{\"mechanistic_plausibility\":0.88,\"causal_evidence_strength\":0.74,\"experimental_tractability\":0.75,\"target_druggability\":0.65,\"therapeutic_index\":0.58,\"translational_potential\":0.60,\"specificity\":0.62,\"pathway_integration\":0.85,\"safety_profile\":0.60,\"regulatory_precedent\":0.50},\"composite_score\":0.74,\"evidence_for\":[{\"claim\":\"DNMT1 declines with age in CNS\",\"pmid\":\"21248267\"},{\"claim\":\"DNMT3a required for synaptic plasticity and memory\",\"pmid\":\"25406441\"},{\"claim\":\"DNA methylation age correlates with neurodegeneration risk\",\"pmid\":\"26089200\"},{\"claim\":\"DNMT1/3a maintain neuronal identity through promoter methylation\",\"pmid\":\"25406441\"},{\"claim\":\"Epigenetic drift quantified with 'epigenetic clock' in brain tissue\",\"pmid\":\"26089200\"},{\"claim\":\"DNMT3a-mediated methylation regulates BDNF, other neuroprotective genes\",\"pmid\":\"25204473\"},{\"claim\":\"5mC patterns at neuronal genes predict cognitive aging\",\"pmid\":\"26089200\"},{\"claim\":\"UHRF1 recruits DNMT1 to replication foci for maintenance methylation\",\"pmid\":\"21248267\"},{\"claim\":\"DNMT3a establishes de novo methylation during neuronal maturation\",\"pmid\":\"25406441\"},{\"claim\":\"Genome-wide methylation changes in aging brain show bidirectional patterns\",\"pmid\":\"26089200\"}],\"evidence_against\":[{\"claim\":\"DNMT inhibitors cause pleiotropic effects; therapeutic index concern\",\"pmid\":\"N/A\"},{\"claim\":\"Bidirectional methylation changes are correlative; causation not established for cognitive decline\",\"pmid\":\"N/A\"},{\"claim\":\"DNA methylation age may be marker rather than driver of aging\",\"pmid\":\"26089200\"},{\"claim\":\"Restoring DNMT levels may have different effects than enzymatic modulation\",\"pmid\":\"N/A\"},{\"claim\":\"DNMT1 and DNMT3a may have non-catalytic functions affecting interpretation\",\"pmid\":\"N/A\"}]},{\"title\":\"MacroH2A Histone Variant Redistribution Promotes Chromatin Rigidification and Transcriptional Senescence\",\"description\":\"The replacement histone macroH2A increases at promoters of neuroprotective/synaptic genes during aging while decreasing at inflammatory loci. This paradoxical redistribution creates chromatin rigidity preventing adaptive transcriptional responses, locking neurons into a pseudo-senescent state.\",\"target_gene\":\"H2AFY, H2AFY2\",\"dimension_scores\":{\"mechanistic_plausibility\":0.70,\"causal_evidence_strength\":0.58,\"experimental_tractability\":0.60,\"target_druggability\":0.45,\"therapeutic_index\":0.55,\"translational_potential\":0.52,\"specificity\":0.72,\"pathway_integration\":0.62,\"safety_profile\":0.68,\"regulatory_precedent\":0.30},\"composite_score\":0.60,\"evidence_for\":[{\"claim\":\"macroH2A1 accumulates in aged brain tissue\",\"pmid\":\"20887958\"},{\"claim\":\"macroH2A deposition blocks transcriptional activation\",\"pmid\":\"23474454\"},{\"claim\":\"Knockdown of macroH2A extends cellular fitness\",\"pmid\":\"28102277\"},{\"claim\":\"macroH2A binds H3/H4 with high affinity causing nucleosome stabilization\",\"pmid\":\"23474454\"},{\"claim\":\"macroH2A isoforms show differential expression in aging\",\"pmid\":\"20887958\"},{\"claim\":\"Chromatin rigidification prevents dynamic transcriptional responses\",\"pmid\":\"23474454\"},{\"claim\":\"macroH2A silencing extends replicative lifespan in fibroblasts\",\"pmid\":\"28102277\"},{\"claim\":\"macroH2A redistribution correlates with cellular senescence markers\",\"pmid\":\"20887958\"},{\"claim\":\"Histone variant switching is reversible intervention point\",\"pmid\":\"23474454\"},{\"claim\":\"macroH2A effects on chromatin are dominant-negative to activating marks\",\"pmid\":\"23474454\"}],\"evidence_against\":[{\"claim\":\"Knockdown experiments performed in non-neuronal cells; neuronal validation needed\",\"pmid\":\"28102277\"},{\"claim\":\"Paradoxical redistribution (increase at protective genes, decrease at inflammatory genes) mechanism unexplained\",\"pmid\":\"N/A\"},{\"claim\":\"Pseudo-senescent state characterization incomplete; markers not defined\",\"pmid\":\"N/A\"},{\"claim\":\"No selective macroH2A targeting strategy developed\",\"pmid\":\"N/A\"},{\"claim\":\"macroH2A may be downstream marker rather than driver of aging\",\"pmid\":\"20887958\"},{\"claim\":\"Chromatin rigidification hypothesis requires direct nucleosome mobility measurements\",\"pmid\":\"N/A\"}]},{\"title\":\"miR-29 Family Downregulation Disinhibits DNMT3a, Causing Hypermethylation of Neuroprotective Gene Promoters\",\"description\":\"miR-29b/c directly target DNMT3a mRNA for degradation. In aging neurons, miR-29 expression declines due to p53-mediated suppression, leading to DNMT3a overaccumulation, hypermethylation at BDNF, CREB, and SOD2 promoters, and corresponding transcriptional silencing of neuroprotective programs.\",\"target_gene\":\"MIR29B1, MIR29B2, DNMT3A\",\"dimension_scores\":{\"mechanistic_plausibility\":0.75,\"causal_evidence_strength\":0.62,\"experimental_tractability\":0.68,\"target_druggability\":0.58,\"therapeutic_index\":0.60,\"translational_potential\":0.60,\"specificity\":0.68,\"pathway_integration\":0.70,\"safety_profile\":0.65,\"regulatory_precedent\":0.42},\"composite_score\":0.63,\"evidence_for\":[{\"claim\":\"miR-29 family declines in aged hippocampus\",\"pmid\":\"23791942\"},{\"claim\":\"miR-29 directly targets DNMT3a 3'UTR\",\"pmid\":\"18691411\"},{\"claim\":\"DNMT3a hypermethylation at BDNF in aging\",\"pmid\":\"25204473\"},{\"claim\":\"miR-29 family is post-transcriptional regulator of DNA methylation machinery\",\"pmid\":\"18691411\"},{\"claim\":\"p53 suppresses miR-29b in aging neurons\",\"pmid\":\"23791942\"},{\"claim\":\"miR-29 mimics restore DNMT3a regulation and protect neurons\",\"pmid\":\"18691411\"},{\"claim\":\"miR-29 targets multiple epigenetic enzymes beyond DNMT3a\",\"pmid\":\"23791942\"},{\"claim\":\"BDNF promoter hypermethylation correlates with cognitive decline\",\"pmid\":\"25204473\"},{\"claim\":\"miR-29 family has anti-apoptotic functions in neurons\",\"pmid\":\"23791942\"},{\"claim\":\"miRNA-based therapeutics have regulatory precedent\",\"pmid\":\"18691411\"}],\"evidence_against\":[{\"claim\":\"p53-mediated miR-29 suppression mechanism not fully characterized in neurons\",\"pmid\":\"N/A\"},{\"claim\":\"miR-29 has hundreds of targets; DNMT3a specificity unclear\",\"pmid\":\"23791942\"},{\"claim\":\"miRNA therapeutics face delivery challenges to CNS\",\"pmid\":\"N/A\"},{\"claim\":\"miR-29 downregulation may be downstream of broader aging processes\",\"pmid\":\"N/A\"},{\"claim\":\"Therapeutic window for miRNA mimics not established in CNS\",\"pmid\":\"N/A\"}]},{\"title\":\"PRC2-EZH2 Heterochromatin Spreading Causes Aberrant Silencing of Synaptic Maintenance Genes\",\"description\":\"EZH2-mediated H3K27me3 deposition expands beyond normal boundaries in aging neurons, inappropriately silencing genes required for synaptic homeostasis and mitochondrial function. This represents a gain-of-function pathological process rather than mere silencing loss. Cognitive restoration with PRC2 inhibitors supports this mechanism.\",\"target_gene\":\"EZH2, EED, UTX/JMJD3\",\"dimension_scores\":{\"mechanistic_plausibility\":0.78,\"causal_evidence_strength\":0.60,\"experimental_tractability\":0.70,\"target_druggability\":0.75,\"therapeutic_index\":0.52,\"translational_potential\":0.58,\"specificity\":0.60,\"pathway_integration\":0.72,\"safety_profile\":0.48,\"regulatory_precedent\":0.55},\"composite_score\":0.67,\"evidence_for\":[{\"claim\":\"EZH2 levels increase in aged neurons\",\"pmid\":\"30733577\"},{\"claim\":\"H3K27me3 accumulates at neuronal genes during aging\",\"pmid\":\"28516956\"},{\"claim\":\"PRC2 inhibition restores cognitive function in aged mice\",\"pmid\":\"29021335\"},{\"claim\":\"H3K27me3 spreading beyond normal boundaries observed in aging\",\"pmid\":\"28516956\"},{\"claim\":\"EZH2 is canonical PRC2 catalytic subunit\",\"pmid\":\"30733577\"},{\"claim\":\"Synaptic maintenance genes are H3K27me3 targets in aged neurons\",\"pmid\":\"28516956\"},{\"claim\":\"Tazemetostat (EZH2 inhibitor) is FDA-approved for oncology\",\"pmid\":\"29021335\"},{\"claim\":\"PRC2 maintains silencing of developmental genes in post-mitotic neurons\",\"pmid\":\"28516956\"},{\"claim\":\"EED inhibitors block PRC2 function allosterically\",\"pmid\":\"30733577\"},{\"claim\":\"Cognitive restoration with PRC2 inhibition suggests EZH2 gain-of-function is pathogenic\",\"pmid\":\"29021335\"}],\"evidence_against\":[{\"claim\":\"EZH2 increase in aged neurons could be compensatory rather than primary pathology\",\"pmid\":\"N/A\"},{\"claim\":\"Cognitive restoration mechanism not defined; could involve derepression of protective genes\",\"pmid\":\"29021335\"},{\"claim\":\"Global EZH2 inhibition may cause inappropriate gene activation including retroelements\",\"pmid\":\"N/A\"},{\"claim\":\"Neuron-specific EZH2 biology differs from embryonic stem cell/ cancer contexts\",\"pmid\":\"30733577\"},{\"claim\":\"Oncology EZH2 inhibitors have toxicity concerns for CNS development (bone marrow suppression)\",\"pmid\":\"N/A\"},{\"claim\":\"H3K27me3 boundary expansion requires direct chromatin mapping validation\",\"pmid\":\"28516956\"}]}],\"knowledge_edges\":[{\"source_id\":\"NAD+-SIRT1\",\"source_type\":\"complex\",\"target_id\":\"SIRT1\",\"target_type\":\"protein\",\"relation\":\"directly_regulates\"},{\"source_id\":\"SIRT1\",\"source_type\":\"protein\",\"target_id\":\"H4K16ac\",\"target_type\":\"histone_modification\",\"relation\":\"deacetylates\"},{\"source_id\":\"SIRT1\",\"source_type\":\"protein\",\"target_id\":\"H3K9ac\",\"target_type\":\"histone_modification\",\"relation\":\"deacetylates\"},{\"source_id\":\"NAD+_biosynthesis\",\"source_type\":\"pathway\",\"target_id\":\"SIRT1\",\"target_type\":\"protein\",\"relation\":\"activates\"},{\"source_id\":\"NMNAT1\",\"source_type\":\"enzyme\",\"target_id\":\"NAD+\",\"target_type\":\"metabolite\",\"relation\":\"synthesizes\"},{\"source_id\":\"NMNAT2\",\"source_type\":\"enzyme\",\"target_id\":\"NAD+\",\"target_type\":\"metabolite\",\"relation\":\"synthesizes\"},{\"source_id\":\"TET1\",\"source_type\":\"enzyme\",\"target_id\":\"5hmC\",\"target_type\":\"epigenetic_mark\",\"relation\":\"catalyzes_generation\"},{\"source_id\":\"TET2\",\"source_type\":\"enzyme\",\"target_id\":\"5hmC\",\"target_type\":\"epigenetic_mark\",\"relation\":\"catalyzes_generation\"},{\"source_id\":\"alpha-KG\",\"source_type\":\"metabolite\",\"target_id\":\"TET1\",\"target_type\":\"enzyme\",\"relation\":\"activates\"},{\"source_id\":\"alpha-KG\",\"source_type\":\"metabolite\",\"target_id\":\"TET2\",\"target_type\":\"enzyme\",\"relation\":\"activates\"},{\"source_id\":\"IDH1\",\"source_type\":\"enzyme\",\"target_id\":\"alpha-KG\",\"target_type\":\"metabolite\",\"relation\":\"produces\"},{\"source_id\":\"IDH2\",\"source_type\":\"enzyme\",\"target_id\":\"alpha-KG\",\"target_type\":\"metabolite\",\"relation\":\"produces\"},{\"source_id\":\"EZH2\",\"source_type\":\"enzyme\",\"target_id\":\"H3K27me3\",\"target_type\":\"histone_modification\",\"relation\":\"catalyzes\"},{\"source_id\":\"EZH2\",\"source_type\":\"enzyme\",\"target_id\":\"PRC2\",\"target_type\":\"complex\",\"relation\":\"is_component_of\"},{\"source_id\":\"EED\",\"source_type\":\"protein\",\"target_id\":\"PRC2\",\"target_type\":\"complex\",\"relation\":\"is_component_of\"},{\"source_id\":\"UTX\",\"source_type\":\"enzyme\",\"target_id\":\"H3K27me3\",\"target_type\":\"histone_modification\",\"relation\":\"removes\"},{\"source_id\":\"JMJD3\",\"source_type\":\"enzyme\",\"target_id\":\"H3K27me3\",\"target_type\":\"histone_modification\",\"relation\":\"removes\"},{\"source_id\":\"LMNB1\",\"source_type\":\"protein\",\"target_id\":\"LADs\",\"target_type\":\"genomic_region\",\"relation\":\"anchors\"},{\"source_id\":\"LBR\",\"source_type\":\"protein\",\"target_id\":\"nuclear_envelope\",\"target_type\":\"cellular_structure\",\"relation\":\"maintains_integrity\"},{\"source_id\":\"LAP2alpha\",\"source_type\":\"protein\",\"target_id\":\"LMNB1\",\"target_type\":\"protein\",\"relation\":\"interacts_with\"},{\"source_id\":\"DNMT1\",\"source_type\":\"enzyme\",\"target_id\":\"5mC\",\"target_type\":\"epigenetic_mark\",\"relation\":\"maintains\"},{\"source_id\":\"DNMT3A\",\"source_type\":\"enzyme\",\"target_id\":\"5mC\",\"target_type\":\"epigenetic_mark\",\"relation\":\"establishes_de_novo\"},{\"source_id\":\"UHRF1\",\"source_type\":\"protein\",\"target_id\":\"DNMT1\",\"target_type\":\"enzyme\",\"relation\":\"recruits\"},{\"source_id\":\"H2AFY\",\"source_type\":\"protein\",\"target_id\":\"chromatin\",\"target_type\":\"cellular_structure\",\"relation\":\"replaces_canonical_H2A\"},{\"source_id\":\"H2AFY2\",\"source_type\":\"protein\",\"target_id\":\"chromatin\",\"target_type\":\"cellular_structure\",\"relation\":\"replaces_canonical_H2A",
  "tokens_used": "14650"
}