{"gene":"H2AZ1","run_date":"2026-06-10T01:55:21","timeline":{"discoveries":[{"year":2003,"finding":"The SWR1 complex, with Swr1 (a Swi2/Snf2-related ATPase) as its catalytic core, catalyzes ATP-dependent exchange of nucleosomal histone H2A for H2A.Z in nucleosome arrays. Swr1 is required for deposition of H2A.Z at specific chromosome locations in vivo.","method":"Biochemical reconstitution of histone exchange activity; in vivo ChIP; genetic analysis in S. cerevisiae","journal":"Science","confidence":"High","confidence_rationale":"Tier 1 / Strong — biochemical reconstitution of ATP-dependent exchange in vitro, corroborated by in vivo ChIP and genetic epistasis, foundational study widely replicated","pmids":["14645854"],"is_preprint":false},{"year":2005,"finding":"Within the SWR1 complex, Swc2 binds directly to H2A.Z and is essential for its transfer into nucleosomes. Swc6 and Arp6 are required for Swc2 association and nucleosome binding; Swc5 and Yaf9 are required for H2A.Z transfer but not for H2A.Z or nucleosome binding. The C-terminal alpha-helix of H2A.Z is crucial for recognition by SWR1.","method":"Biochemical dissection of SWR1 subunit interactions; pulldown/co-IP; in vitro histone exchange assay; mutagenesis of H2A.Z C-terminal helix","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple orthogonal biochemical methods including mutagenesis and in vitro exchange assays in a single focused study","pmids":["16299513"],"is_preprint":false},{"year":2007,"finding":"H2A.Z nucleosomes occupy a single predominant rotational setting and multiple translational settings in the S. cerevisiae genome, flanking nucleosome-free regions at promoters of both active and inactive genes, with transcription factor binding sites rotationally exposed near nucleosome borders.","method":"Deep sequencing of 322,000 individual H2A.Z-containing nucleosomes (genome-wide nucleosome positioning)","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — comprehensive genome-wide sequencing with median 4-bp resolution, providing foundational genomic architecture data replicated in subsequent studies","pmids":["17392789"],"is_preprint":false},{"year":2000,"finding":"H2A.Z regulates gene transcription in S. cerevisiae; deletion of H2A.Z strongly increases the requirement for SNF/SWI and SAGA remodeling complexes (synthetic genetic interaction). H2A.Z is preferentially crosslinked to intergenic DNA at PHO5 and GAL1 loci, and this association changes with transcriptional activation, placing H2A.Z in a distinct pathway from SNF/SWI and SAGA for chromatin-based transcriptional regulation.","method":"Genetic epistasis (synthetic lethality/sick interactions); chromatin immunoprecipitation (ChIP) at specific loci in S. cerevisiae","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis plus direct ChIP localization, independently replicated across multiple subsequent studies","pmids":["11081628"],"is_preprint":false},{"year":2008,"finding":"H2A.Z occupies promoters of developmentally important genes in mouse ES cells in a manner similar to Polycomb group protein Suz12. H2A.Z and PcG protein occupancy is interdependent at promoters (RNAi depletion of H2A.Z reduces PcG occupancy and vice versa), and H2A.Z is necessary for ES cell differentiation and lineage commitment.","method":"Genome-wide ChIP-seq; RNAi knockdown with gene expression and differentiation assays in mouse ES cells","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — genome-wide ChIP-seq combined with RNAi functional knockdown and differentiation readouts in a focused study","pmids":["18992931"],"is_preprint":false},{"year":2007,"finding":"A fraction of mammalian H2A.Z is monoubiquitylated; on the inactive X chromosome the majority of H2A.Z is ubiquitylated. Monoubiquitylation of H2A.Z is mediated by the RING1b E3 ligase of the human Polycomb complex, distinguishing H2A.Z associated with facultative heterochromatin from euchromatin-associated H2A.Z.","method":"Biochemical fractionation; co-immunoprecipitation; immunofluorescence; identification of RING1b as the E3 ligase","journal":"Molecular and cellular biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP and fractionation identify RING1b as writer, single lab with multiple orthogonal methods","pmids":["17636032"],"is_preprint":false},{"year":2008,"finding":"DNA methylation and H2A.Z deposition are mutually antagonistic in Arabidopsis: regions of DNA methylation are quantitatively deficient in H2A.Z. Mutation of MET1 DNA methyltransferase causes losses of H2A.Z at sites gaining methylation and gains of H2A.Z at sites losing methylation; mutation of PIE1 (SWR1 complex subunit) leads to genome-wide hypermethylation. This demonstrates that DNA methylation excludes H2A.Z and H2A.Z protects genes from DNA methylation.","method":"ChIP-chip; genetic analysis of met1 and pie1 mutants with genome-wide methylation and H2A.Z profiling in Arabidopsis","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal genetic and genomic analyses across two mutants, later replicated in mammals","pmids":["18815594"],"is_preprint":false},{"year":2009,"finding":"H2A.Z incorporation into promoter chromatin of estrogen receptor (ERα) target genes occurs upon gene induction in a cyclic pattern, mediated by the p400 complex. Cellular depletion of H2A.Z or p400 causes severe defects in estrogen signaling and estrogen-specific cell proliferation. H2A.Z incorporation allows nucleosomes to adopt preferential translational positions at the TFF1 promoter and is essential for estrogen-responsive enhancer function.","method":"ChIP-seq; RNAi knockdown; gene expression analysis; nucleosome positioning assay in human cells","journal":"Genes & development","confidence":"High","confidence_rationale":"Tier 2 / Strong — ChIP-seq, RNAi functional knockdown, nucleosome positioning, and enhancer assays using multiple orthogonal methods","pmids":["19515975"],"is_preprint":false},{"year":2009,"finding":"H2A.Z loaded at 5' ends of genes by the Swr1 complex containing a JmjC domain protein mediates suppression of antisense transcripts in fission yeast. H2A.Z is partially redundant with the Clr4-containing heterochromatin complex and RNAi component Ago1 in suppressing antisense transcripts that are normally degraded by the exosome.","method":"Genetic epistasis (H2A.Z/Clr4/Ago1 double and triple mutant analysis); ChIP; RNA analysis in S. pombe","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with multiple combinatorial mutants plus ChIP localization, Nature-level study","pmids":["19693008"],"is_preprint":false},{"year":2009,"finding":"H2A.Z deposition in fission yeast requires a novel JmjC domain protein Msc1 as a component of the Swr1 complex. Loss of Msc1, Swr1, or H2A.Z results in loss of centromere silencing and defective chromosome segregation. H2A.Z is required for expression of the centromere protein CENP-C, and overexpression of CENP-C rescues centromere silencing defects associated with H2A.Z loss.","method":"Genetic analysis; ChIP; epistasis rescue experiments in S. pombe","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with rescue experiment, single lab","pmids":["19910462"],"is_preprint":false},{"year":2013,"finding":"SETD6 lysine methyltransferase monomethylates H2A.Z at lysine 7 (H2AZK7me1). This modification increases upon differentiation of mouse embryonic stem cells; H2AZK7me1 and H3K27me3 co-occupy transcription start sites of differentiation marker genes. Depletion of Setd6 leads to cellular differentiation and compromised self-renewal in mESCs.","method":"In vitro methyltransferase assay; mass spectrometry; ChIP; siRNA knockdown in mESCs","journal":"Epigenetics","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — in vitro enzymatic assay identifies SETD6 as writer plus ChIP and functional knockdown, single lab","pmids":["23324626"],"is_preprint":false},{"year":2015,"finding":"H2A.Z.2 (encoded by H2AFV) interacts with BRD2 bromodomain protein. H2A.Z.2 controls transcriptional output of E2F target genes in melanoma; BRD2 binding to H2A.Z.2-regulated genes is dependent on H2A.Z.2 levels. H2A.Z.2 deficiency sensitizes melanoma cells to chemotherapy and targeted therapies.","method":"Co-immunoprecipitation; ChIP-seq; RNAi knockdown; integrated genomic analyses in melanoma cells","journal":"Molecular cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP and ChIP-seq in a single lab study; note this concerns H2A.Z.2 (H2AFV), not H2A.Z.1/H2AFZ","pmids":["26051178"],"is_preprint":false},{"year":2015,"finding":"H2A.Z in human cells is rapidly removed from chromatin flanking DNA damage by the INO80 remodeling complex. The histone chaperone ANP32E also promotes homologous recombination and works in the same pathway as INO80 for H2A.Z removal. The HR defect in INO80- or ANP32E-depleted cells is rescued by co-depletion of H2A.Z, demonstrating that H2A.Z removal from chromatin is the primary function of INO80 and ANP32E in promoting HR.","method":"ChIP; epistasis rescue (co-depletion); siRNA knockdown; HR reporter assay in human cells","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — epistasis rescue with co-depletion and HR functional assay, multiple orthogonal methods establishing pathway placement","pmids":["26142279"],"is_preprint":false},{"year":2016,"finding":"The crystal structure of Drosophila YL1 (Swc2) H2A.Z-binding domain (dYL1-Z) in complex with H2A.Z-H2B dimer at 1.9-Å resolution reveals a whip-like structure that wraps over H2A.Z-H2B. Preferential recognition is conferred by three residues in loop 2, the hyperacidic patch, and the extended αC helix of H2A.Z. This domain is essential for H2A.Z deposition in vivo and SRCAP(SWR1)-catalyzed replacement in vitro.","method":"Crystal structure (1.9 Å); in vitro histone replacement assay; in vivo deposition assay; mutagenesis","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution crystal structure with mutagenesis and functional in vitro/in vivo validation, two independent structural papers published simultaneously","pmids":["26974124"],"is_preprint":false},{"year":2016,"finding":"YL1 is a specific H2A.Z-deposition chaperone in metazoans. Crystal structure at 2.7 Å of the human YL1-H2A.Z-H2B complex shows YL1 binding triggers extension of the H2A.Z αC helix and contacts the extended acidic patch and entire DNA-binding surface of H2A.Z-H2B. Only four amino acid substitutions in H2A are sufficient to create an H2A.Z-like interface recognized by YL1.","method":"Crystal structure (2.7 Å); biochemical binding assays; mutagenesis","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution crystal structure with mutagenesis establishing molecular basis for H2A.Z-specific recognition","pmids":["26974126"],"is_preprint":false},{"year":2016,"finding":"SMYD3 methyltransferase dimethylates H2A.Z.1 at lysine 101 (H2A.Z.1K101me2), which increases H2A.Z.1 stability by preventing binding to the removal chaperone ANP32E and facilitating interaction with histone H3. SMYD3 and H2A.Z.1K101me2 co-localize at the cyclin A1 promoter, activating its expression and G1-S progression.","method":"In vitro methyltransferase assay; co-immunoprecipitation; ChIP; cyclin A1 rescue in mouse model; microarray","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — in vitro enzymatic assay plus co-IP and ChIP, single lab","pmids":["27569210"],"is_preprint":false},{"year":2016,"finding":"H2A.Z.1 monoubiquitylation (H2A.Z.1ub) at PRC1 target residues is required to maintain Polycomb binding and repress bivalent genes in mESCs. Loss of monoubiquitylation (K3R3 mutant) leads to de-repression of bivalent genes and faulty lineage commitment. Tandem bromodomain protein BRD2 is enriched in H2A.Z.1 chromatin and is gained at de-repressed promoters in H2A.Z.1(K3R3) mESCs; BRD2 inhibition restores gene silencing, revealing an antagonistic relationship between H2A.Z.1ub and BRD2.","method":"Mutagenesis (H2A.Z.1K3R3); ChIP; quantitative proteomics; BRD2 inhibition rescue experiment in mESCs","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — mutagenesis, ChIP, quantitative proteomics, and pharmacological rescue across multiple orthogonal methods in a single study","pmids":["26804911"],"is_preprint":false},{"year":2017,"finding":"Unlike other chromatin remodelers that translocate at the H3-H4 interface, INO80 translocates along DNA at the H2A-H2B interface of nucleosomes and persistently displaces DNA from H2A-H2B, generating DNA torsional strain near the entry site. This unique translocation mechanism drives both nucleosome mobilization and selective exchange of H2A.Z-H2B dimers for H2A-H2B without additional histone chaperones. INO80 translocates and mobilizes H2A.Z-containing nucleosomes more efficiently than H2A-containing nucleosomes.","method":"Biochemical translocation assays; single-molecule analysis; histone exchange assays in vitro; mutant analysis","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with single-molecule analysis and mutagenesis distinguishing INO80 mechanism from other remodelers","pmids":["28604691"],"is_preprint":false},{"year":2017,"finding":"PWWP2A is a novel H2A.Z-nucleosome binding protein identified by H2A.Z interactome analysis. PWWP2A binds H2A.Z-containing nucleosomes via multivalent interaction (two internal regions for H2A.Z-specificity/nucleosome contact, PWWP domain for DNA binding). The C-terminal tail of H2A.Z mediates PWWP2A recruitment. PWWP2A depletion impairs cell proliferation via mitotic delay and causes neural crest cell defects in Xenopus.","method":"Co-immunoprecipitation interactome; domain mapping; genome-wide ChIP-seq; siRNA knockdown; Xenopus knockdown","journal":"The EMBO journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — comprehensive interactome plus ChIP-seq and functional knockdown in multiple systems, single lab","pmids":["28645917"],"is_preprint":false},{"year":2014,"finding":"H2A.Z is actively exchanged in the hippocampus and cortex in response to fear conditioning. H2A.Z exchange mediates gene expression and restrains formation of recent and remote memory. H2A.Z acts as a negative regulator of hippocampal consolidation and systems consolidation.","method":"Fear conditioning behavioral paradigm; ChIP; gene expression analysis in mouse hippocampus and cortex","journal":"Nature","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP demonstrating active exchange plus behavioral readout, single lab","pmids":["25219850"],"is_preprint":false},{"year":2019,"finding":"H2A.Z-containing nucleosomes are enriched with H4K20me2 and bound ORC in HeLa cells. H2A.Z-nucleosomes bind directly to SUV420H1, promoting H4K20me2 deposition, which is required for ORC1 binding at replication origins. Depletion of H2A.Z reduces H4K20me2, ORC1 binding, and nascent-strand signals genome-wide, impairing early replication origin licensing and activation.","method":"In vitro binding assays; ChIP-seq; nascent strand sequencing; H2A.Z depletion in HeLa cells; genome-wide co-localization","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro direct binding plus genome-wide ChIP-seq and functional depletion, multiple orthogonal methods","pmids":["31875854"],"is_preprint":false},{"year":2023,"finding":"Cryo-EM structure of SUV420H1 bound to H2A.Z-nucleosome reveals direct interaction with H4 N-terminal tail (H4 residues 1-24 forming a lasso-shaped structure projecting H4K20 into the catalytic center), DNA, and nucleosome acidic patch. The SUV420H1 KR loop (residues 214-223) lies close to H2A.Z-specific residues D97/S98 and is crucial for preferential recognition of H2A.Z-nucleosome over canonical H2A-nucleosome.","method":"Cryo-EM structure; in vitro methyltransferase assay; mutagenesis; in vivo analysis","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structure with mutagenesis and in vitro/in vivo functional validation","pmids":["37536340"],"is_preprint":false},{"year":2014,"finding":"The +1 nucleosome is a major barrier to elongating RNAPII for essentially all genes. The extent of this barrier anticorrelates with enrichment of H2A.Z: depletion of H2A.Z from a nucleosome position results in a higher barrier to RNAPII. This shows H2A.Z incorporation at the +1 nucleosome reduces the transcriptional barrier.","method":"Genome-wide native elongating transcript sequencing (NET-seq) at nucleotide resolution; H2A.Z depletion in yeast","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — genome-wide direct measurement of RNAPII stalling combined with H2A.Z depletion functional experiment","pmids":["24606920"],"is_preprint":false},{"year":2012,"finding":"H2A.Z.2.2, an alternatively spliced variant of H2A.Z, binds to TIP60 and SRCAP chaperone complexes and is actively deposited into chromatin in a replication-independent manner. Its unique C-terminus causes major structural destabilization of nucleosomes as demonstrated by biochemical fractionation, FRAP, size exclusion chromatography, single-molecule FRET, and molecular dynamics simulations.","method":"Co-immunoprecipitation with TIP60/SRCAP complexes; FRAP; size exclusion chromatography; single-molecule FRET; molecular dynamics simulations; deletion mutant analysis","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple independent in vitro and in vivo methods (FRET, FRAP, biochemistry, MD) consistently demonstrating nucleosome destabilization","pmids":["22467210"],"is_preprint":false},{"year":2009,"finding":"Acetylation sites of vertebrate H2A.Z (K4, K7, K11, K13, K15) were identified from chicken erythrocytes. H2A.Z stabilizes the nucleosome core particle (NCP) regardless of its acetylation state. Acetylated H2A.Z variants act synergistically with other acetylated core histones to alter NCP conformation. Heteromorphic NCPs containing both H2A.Z and H2A are slightly destabilized only in the presence of acetylation.","method":"Mass spectrometry (acetylation site identification); NCP reconstitution with acetylated histones and H2A.Z(K/Q) acetylation mimic mutants; biochemical stability assays","journal":"Biochemistry","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with mutagenesis and NCP stability assays, single lab","pmids":["19385636"],"is_preprint":false},{"year":2019,"finding":"Znhit1, a subunit of the SRCAP complex, incorporates H2A.Z into TSS regions of genes governing Lgr5+ intestinal stem cell fate (Lgr5, Tgfb1, Tgfbr2). Mechanistically, Znhit1 promotes H2A.Z incorporation by controlling phosphorylation of the H2A.Z chaperone YL1, enhancing YL1-H2A.Z interaction.","method":"Conditional knockout mouse; ChIP-seq; co-immunoprecipitation; phosphorylation analysis; intestinal stem cell functional assays","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional KO with ChIP-seq and co-IP mechanism, single lab","pmids":["30842416"],"is_preprint":false},{"year":2018,"finding":"H2A.Z deposition and acetylation by the TRRAP/p400/Tip60 complex (which physically associates with transcription factor RBP-J at Notch-dependent enhancers) is required for tight control of canonical Notch target gene activation. Tip60 acetylates H2A.Z when targeted to RBP-J-bound enhancers, upregulating Notch target genes. Drosophila homologs of Tip60, p400, and H2A.Z modulate Notch signaling in vivo.","method":"ChIP; co-immunoprecipitation; siRNA knockdown; in vivo Drosophila genetic analysis; gene expression assays","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP, ChIP, and in vivo genetic validation across two organisms, single lab","pmids":["29986055"],"is_preprint":false},{"year":2013,"finding":"KAT2A (GCN5) acetylates H2A.Z.1 at promoters of transactivated genes. The DNA repair complex XPC-RAD23-CEN2 interacts with both H2A.Z and KAT2A, recruiting KAT2A to promoters to license H2A.Z.1 acetylation. KAT2A selectively acetylates H2A.Z.1 but not H2A.Z.2 in vitro; alanine-14 in H2A.Z.2 inhibits KAT2A activity. Acetyl-H2A.Z.1 recruits BRD2 to promote RNAPII recruitment.","method":"In vitro acetyltransferase assay; co-immunoprecipitation; ChIP; mutagenesis (non-acetylable H2A.Z.1); RNAPII recruitment assay","journal":"Nature chemical biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro enzymatic assay with mutagenesis plus ChIP and co-IP, identifying writer and reader in one study","pmids":["31527837"],"is_preprint":false},{"year":2022,"finding":"TIP60 (KAT5) is essential for acetylation of H2A.Z specifically at lysine 7 in human and mouse cells. Loss of TIP60 causes complete cell growth arrest with failure of chromosome alignment during mitosis. This growth arrest is independent of p53, INK4A, and ARF tumor suppressors.","method":"Inducible Cre-recombinase and CRISPR/Cas9 deletion of TIP60; ChIP; RNA-seq; cell cycle analysis; live imaging of mitosis","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO with ChIP confirming H2A.Z K7 acetylation loss plus functional phenotypic readouts, single lab","pmids":["35853868"],"is_preprint":false},{"year":2022,"finding":"Tip60 acetyltransferase acetylates H2A.Z, and loss of H2A.Z acetylation interferes with H3K4me3 deposition and activation of bivalent, lineage-restricted genes during neuronal fate specification. H2A.Z acetylation does not affect chromatin accessibility but is required for epigenetic competence (bivalent chromatin activation) during cell lineage transition.","method":"Proteomics; genetic depletion of Tip60; ChIP-seq; ATAC-seq; RNA-seq; neuronal differentiation assays","journal":"Molecular cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic depletion with ChIP-seq, ATAC-seq, and RNA-seq, single lab","pmids":["36417913"],"is_preprint":false},{"year":2020,"finding":"H2A.Z nucleosomes are more enriched in unwrapped states compared with canonical nucleosomes in mouse ES cells, as measured by MNase-X-ChIP-seq. Depletion of H2A.Z results in decreased unwrapping of H3.3 nucleosomes and increased CTCF binding, demonstrating that H2A.Z regulates nucleosome unwrapping in vivo and that its transcriptional and CTCF-regulatory functions correlate with nucleosome unwrapping states.","method":"MNase-X-ChIP-seq; re-ChIP; CTCF CUT&RUN; H2A.Z depletion in mouse ES cells","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — novel sequencing method plus functional depletion with CTCF binding readout, single lab","pmids":["32392318"],"is_preprint":false},{"year":2021,"finding":"Cryo-EM structures of H2A.Z-containing nucleosomes and chromatin fibers show that H2A.Z incorporation increases mobility of DNA termini in nucleosomes (due to its shorter C-terminus) while simultaneously enabling nucleosome arrays to form a more regular and condensed chromatin fiber. This structural basis provides a mechanistic explanation for H2A.Z's dual activating and repressive transcriptional roles.","method":"Cryo-EM structure of nucleosome and chromatin fiber; deletion mutant analysis of H2A.Z C-terminus","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structures of both nucleosome and chromatin fiber with mutagenesis validation","pmids":["34643712"],"is_preprint":false},{"year":2020,"finding":"Cryo-EM structure of H2A.Z.2.2-containing nucleosome (Z.2.2-NCP) shows it compacts ~125 bp of DNA (less than canonical ~147 bp). Nineteen H2A.Z.2.2-specific residues including a ROF ('regulating-octamer-folding') sequence are responsible for nucleosome opening and also required for SWR1-dependent histone replacement.","method":"Cryo-EM structure; MNase digestion assay; mutagenesis of ROF sequence; SWR1-dependent replacement assay","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 / Strong — cryo-EM structure with mutagenesis and functional assay for SWR1-mediated replacement","pmids":["33073403"],"is_preprint":false},{"year":2022,"finding":"Single-molecule FRET analysis of SWR1-mediated H2A.Z deposition reveals three ATP-dependent phases: (1) a priming step involving transient DNA unwrapping and histone octamer deformations; (2) rapid loss of H2A-H2B; (3) release of displaced H2A-H2B from the SWR1-nucleosome complex, facilitated by histone chaperones. SWR1 intrinsically senses long-linker DNA to preferentially exchange H2A.Z on the distal face of asymmetrically positioned nucleosomes.","method":"Three-color single-molecule FRET; ensemble biochemical assays; real-time single nucleosome remodeling imaging","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 1 / Strong — single-molecule reconstitution resolving mechanism with temporal precision across multiple ATP-dependent steps","pmids":["35263135"],"is_preprint":false},{"year":2022,"finding":"SWR1C (yeast SWR1 complex) uses multiple ATP-dependent steps for H2A.Z deposition, identified by single-molecule and ensemble methods: an initial priming step (transient DNA unwrapping and octamer deformations), rapid H2A loss, and subsequent H2A/H2B release from the H2A.Z nucleosomal product. Rates of priming and H2A/H2B dimer release are sensitive to ATP concentration.","method":"Single-molecule real-time analysis of nucleosome remodeling; ensemble histone exchange assays; ATP concentration titrations","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — single-molecule reconstitution and ensemble biochemistry identifying discrete mechanistic steps","pmids":["36396651"],"is_preprint":false},{"year":2019,"finding":"The crystal structure of the Chz1-H2A.Z-H2B ternary complex reveals that Chz1 uses two distinct structural domains: the middle region (Chz1-M) directly interacts with H2A.Z-specific residues Gly98 and Ala57 for modest preferential binding; the C-terminal region (Chz1-C) harbors a DEF/Y motif engaging an arginine finger and hydrophobic pocket in H2A.Z-H2B, enhancing binding preference. Chz1 facilitates SWR1-mediated H2A.Z deposition by controlling bioavailability of free H2A.Z.","method":"Crystal structure; biochemical binding assays; mutagenesis; in vitro SWR1 histone deposition assay","journal":"PLoS biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure with mutagenesis and in vitro functional deposition assay","pmids":["31107867"],"is_preprint":false},{"year":2017,"finding":"Nap1 and Chz1 have redundant roles as histone chaperones for H2A.Z deposition in S. cerevisiae. They use different H2A.Z surface residues for interaction. Loss of either Nap1 or Chz1 alone causes mild H2A.Z deposition defects, but deletion of both results in significant reduction of H2A.Z at promoters and heterochromatin spreading.","method":"Structural modeling; molecular dynamics simulations; mutagenesis; ChIP; genetic double deletion analysis in S. cerevisiae","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — genetic epistasis with ChIP and computational structural modeling, single lab","pmids":["28883625"],"is_preprint":false},{"year":2021,"finding":"H2A.Z.1 and H2A.Z.2 have non-redundant functions in cell division. H2A.Z.1 regulates expression of cell cycle genes (Myc, Ki-67) and its depletion leads to G1 arrest and cellular senescence. H2A.Z.2, in a transcription-independent manner, is essential for centromere integrity and sister chromatid cohesion regulation, playing a key role in chromosome segregation.","method":"Isoform-specific siRNA depletion; cell cycle analysis; live-cell imaging; ChIP-seq; RNA-seq in human cells","journal":"EMBO reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — isoform-specific depletion with cell cycle and chromosome segregation readouts, single lab","pmids":["34423893"],"is_preprint":false},{"year":2021,"finding":"H2A.Z.1 and H2A.Z.2 have specific interactors (identified by mass spectrometry) that can mediate functional antagonism. They can replace each other at transcription start sites and regulate both distinct and overlapping gene sets in a context-dependent manner. The balance between the two isoforms at promoters critically regulates specific gene expression.","method":"Endogenously-tagged protein immunoprecipitation; mass spectrometry; RNA-seq; ChIP-seq in human cells","journal":"eLife","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — endogenous tagging with mass spectrometry and genome-wide analysis, single lab","pmids":["32109204"],"is_preprint":false},{"year":2023,"finding":"SENP5 deSUMOylates H2A.Z, and this modification regulates homologous recombination-mediated DNA damage repair. The SUMOylation balance of H2A.Z modulates HR repair and cancer radioresistance. H2A.Z was identified as a SENP5 deSUMOylation substrate by SUMO-proteomic mass spectrometry and co-immunoprecipitation.","method":"SUMO-proteomic mass spectrometry; co-immunoprecipitation; HR reporter assay; siRNA knockdown; PDO and PDX models","journal":"Journal of experimental & clinical cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mass spectrometry identification plus co-IP and functional HR assay, single lab","pmids":["37684630"],"is_preprint":false},{"year":2023,"finding":"TORC1 activates the Rpd3L histone deacetylase complex to deacetylate H2A.Z, blocking its deposition into chromatin at autophagy-related gene promoters. Simultaneously, Rpd3L deacetylates the chromatin remodeler Ino80 at K929, stabilizing it and enabling H2A.Z eviction from autophagy genes. This TORC1-Rpd3L-H2A.Z axis represses autophagy-related gene transcription under nutrient-rich conditions.","method":"Biochemical deacetylase assays; co-immunoprecipitation; ChIP; genetic epistasis; rapamycin treatment in yeast","journal":"Science advances","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — biochemical assays plus genetic epistasis and ChIP, single lab","pmids":["36888706"],"is_preprint":false},{"year":2020,"finding":"VPS72/YL1 mediates H2A.Z deposition required for nuclear reassembly after mitosis. Depletion of VPS72 or H2A.Z by siRNA or in vitro depletion results in malformed and nonfunctional nuclei. VPS72 functions outside of the SRCAP and EP400 remodeling complexes for this specific H2A.Z deposition activity.","method":"Cell-free nuclear reassembly assay; siRNA knockdown; live-cell imaging; biochemical fractionation","journal":"Cells","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-free reconstitution assay plus live-cell imaging and siRNA, single lab","pmids":["32708675"],"is_preprint":false},{"year":2017,"finding":"H2A.Z promotes cotranscriptional splicing of suboptimal introns in S. pombe. H2A.Z and Swr1 ATPase are required during temperature stress for efficient splicing of introns with nonconsensus splice sites. Mutating affected splice sites to consensus suppresses the H2A.Z requirement for splicing of that intron. Overexpression of splicing ATPase Prp16 suppresses growth and splicing defects of H2A.Z mutants, placing H2A.Z upstream of Prp16 in a pathway promoting weak intron recognition.","method":"Epistatic miniarray profiles (EMAP); splicing microarray; splice site mutagenesis; genetic suppression by Prp16 overexpression in S. pombe","journal":"Genes & development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with splice-site mutagenesis rescue and splicing microarray, single lab","pmids":["28446597"],"is_preprint":false},{"year":2021,"finding":"H2A.Z depletion in terminally differentiated post-mitotic muscle cells in vivo shows that H2A.Z is dispensable for maintaining or activating transcription in the absence of cell division, as shown by ChIP-seq, RNA-seq, and ATAC-seq. H2A.Z enrichment at active promoters is a marker but not a driver of transcription in post-mitotic cells.","method":"In vivo conditional H2A.Z knockout in post-mitotic muscle; ChIP-seq; RNA-seq; ATAC-seq","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo conditional KO with genome-wide readouts; this is a negative mechanistic finding (H2A.Z dispensable for transcription in post-mitotic cells), single lab","pmids":["32266374"],"is_preprint":false},{"year":2021,"finding":"In Drosophila embryos, H2A.Z enrichment at transcription start sites precedes ZGA and RNA Pol II loading. In vivo knockdown of Domino (H2A.Z chaperone/ATPase) reduces H2A.Z deposition at TSS, causes global downregulation of housekeeping genes at ZGA, and compromises establishment of 3D chromatin structure.","method":"GRO-seq; HiC; ChIP-seq; in vivo RNAi knockdown in Drosophila embryos","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — GRO-seq, HiC, ChIP-seq, and in vivo knockdown, single lab","pmids":["34853314"],"is_preprint":false},{"year":2018,"finding":"H2A.Z promotes meiotic DNA double-strand break formation in fission yeast. In H2A.Z-lacking mutants, multiple proteins involved in DSB formation (including Spo11 homolog and its regulators) show reduced chromatin association, and nuclei are more compact. H2A.Z promotes DSB formation by modulating chromosome architecture to enhance interaction between DSB-related proteins and cohesin-loaded chromatin.","method":"ChIP; meiotic DSB assay; nuclear architecture analysis; genetic analysis in S. pombe","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP and DSB functional assay with nuclear architecture analysis, single lab","pmids":["29145618"],"is_preprint":false},{"year":2018,"finding":"H2A.Z.1 regulates gliogenesis by cooperating with histone chaperone ASF1a to regulate H3K56 acetylation (H3K56ac), which in turn directly affects expression of FOLR1 (folate receptor 1). FOLR1 participates in gliogenesis through the JAK-STAT signaling pathway.","method":"siRNA knockdown; ChIP; RNA-seq; co-immunoprecipitation with ASF1a; neural precursor cell differentiation assays","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP, ChIP, and differentiation functional assays, single lab","pmids":["29982651"],"is_preprint":false},{"year":2015,"finding":"The DREAM complex (containing C. elegans lin-35/Rb homolog) promotes high gene-body H2A.Z (HTZ-1) levels at target genes. In lin-35 mutants, DREAM targets show reduced gene body H2A.Z and increased expression. Many DREAM targets are also upregulated in htz-1/H2A.Z mutants, indicating that gene body H2A.Z plays a repressive role at DREAM target genes.","method":"ChIP-seq; genetic epistasis (lin-35 and htz-1 mutants); RNA-seq in C. elegans","journal":"Genes & development","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP-seq with genetic epistasis in two mutant backgrounds, single lab","pmids":["25737279"],"is_preprint":false},{"year":2024,"finding":"The role of H2A.Z.1 in memory depends on its acetylation status: acetyl-mimic H2A.Z.1 (K4/7/11Q) improves memory, while acetyl-defective H2A.Z.1 (K4/7/11A) impairs memory. H2A.Z.1KA preferentially affects genes involved in synaptic function. H2A.Z.1 depletion or expression of lysine mutants influences alternative splicing of neuronal genes, revealing that H2A.Z.1 regulates both gene expression and splicing in neurons through post-translational modifications.","method":"AAV-mediated overexpression of acetyl-mimic and acetyl-defective H2A.Z.1 mutants; fear conditioning behavioral assays; RNA-seq; splicing analysis in mouse hippocampus","journal":"Neuropsychopharmacology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — acetylation-mimic/defective mutagenesis in vivo with behavioral and transcriptomic readouts, single lab","pmids":["38366138"],"is_preprint":false},{"year":2021,"finding":"Somatic mutations in SRCAP complex subunit genes cause defective H2A.Z deposition in uterine leiomyomas. In these tumors, H2A.Z loss at TSS is associated with increased chromatin accessibility and upregulation of bivalent embryonic stem cell genes. Germline mutations in SRCAP members YEATS4 and ZNHIT1 predispose to uterine leiomyoma through epigenetic instability caused by deficient H2A.Z deposition.","method":"Whole-genome sequencing; ATAC-seq; ChIP-seq; HiChIP; RNA-seq of primary tumor tissues","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 / Strong — comprehensive multi-omic analysis of primary human tissues establishing mechanistic connection between SRCAP mutations, H2A.Z deposition defects, and chromatin/gene expression changes","pmids":["34349258"],"is_preprint":false}],"current_model":"H2A.Z (H2AZ1/H2AFZ) is a conserved histone H2A variant that is incorporated into nucleosomes flanking gene promoters, enhancers, and regulatory elements in an ATP-dependent manner by the SWR1/SRCAP multi-subunit remodeling complex (with YL1/Swc2 serving as the specific H2A.Z recognition subunit via a whip-like structural domain engaging H2A.Z's hyperacidic patch and extended αC helix), while the INO80 complex performs the reverse reaction—removing H2A.Z-H2B dimers via a unique translocation mechanism at the H2A-H2B interface. H2A.Z incorporation at the +1 nucleosome reduces the transcriptional barrier to RNA polymerase II, promotes DNA unwrapping and chromatin accessibility, and enables formation of more regular condensed chromatin fiber arrays; its function is context-dependent, tuned by post-translational modifications including acetylation (by TIP60/KAT5 at K7 and K4/7/11/13/15, and by KAT2A/GCN5 at H2A.Z.1 specifically, which recruits BRD2 to promote RNAPII), monomethylation (by SETD6 at K7, associated with differentiation), dimethylation (by SMYD3 at K101, stabilizing H2A.Z and preventing ANP32E-mediated removal), monoubiquitylation (by RING1b/PRC1 at K3, maintaining Polycomb repression and antagonizing BRD2), deSUMOylation (by SENP5, promoting HR repair), and molecular crosstalk with DNA methylation (mutually antagonistic distributions genome-wide). H2A.Z also scaffolds SUV420H1-mediated H4K20me2 deposition at replication origins to license and activate early DNA replication, and participates in chromosome segregation, meiotic DSB formation, alternative pre-mRNA splicing of weak introns, suppression of antisense transcripts (redundantly with RNAi and heterochromatin factors), memory consolidation in the hippocampus and cortex, and neural crest cell differentiation via the PWWP2A interaction network."},"narrative":{"mechanistic_narrative":"H2A.Z (H2AZ1/H2AFZ) is a conserved histone H2A variant deposited into nucleosomes flanking promoters and regulatory elements, where it tunes the chromatin template for transcription, replication, and genome stability [PMID:14645854, PMID:11081628, PMID:17392789]. Its incorporation is catalyzed by the ATP-dependent SWR1/SRCAP-family remodeler, in which the Swr1/Domino ATPase drives histone exchange and the Swc2/YL1 (VPS72) subunit provides H2A.Z-specific recognition through a whip-like domain that engages the variant's hyperacidic patch and extended αC helix [PMID:14645854, PMID:16299513, PMID:26974124, PMID:26974126]; single-molecule analysis resolves deposition into discrete priming, H2A loss, and dimer-release steps assisted by chaperones such as Chz1 and Nap1 [PMID:35263135, PMID:36396651, PMID:31107867, PMID:28883625]. The reverse reaction is performed by INO80, which translocates uniquely at the H2A-H2B interface to evict H2A.Z-H2B dimers, working with the chaperone ANP32E [PMID:28604691, PMID:26142279]. Structurally, H2A.Z's shorter C-terminus increases mobility of nucleosomal DNA termini and unwrapping while enabling more regular, condensed chromatin fibers, providing a basis for its context-dependent activating and repressive roles [PMID:34643712, PMID:32392318, PMID:24606920]. At the +1 nucleosome H2A.Z lowers the barrier to elongating RNA Pol II [PMID:24606920], and it cooperates with Polycomb—being monoubiquitylated by RING1b to maintain repression of bivalent genes while antagonizing the bromodomain reader BRD2 [PMID:17636032, PMID:26804911]—and is mutually antagonistic with DNA methylation genome-wide [PMID:18815594]. H2A.Z function is further tuned by post-translational modifications: acetylation by TIP60/KAT5 (notably at K7) and by KAT2A/GCN5 on H2A.Z.1 (recruiting BRD2 to promote RNAPII), monomethylation by SETD6 at K7, and dimethylation by SMYD3 at K101 that stabilizes the variant against ANP32E removal [PMID:35853868, PMID:31527837, PMID:23324626, PMID:27569210]. Beyond transcription, H2A.Z scaffolds SUV420H1-mediated H4K20me2 to license early replication origins [PMID:31875854, PMID:37536340], supports chromosome segregation and centromere integrity, ES cell differentiation and lineage commitment, memory consolidation, and is required for proper nuclear reassembly after mitosis [PMID:34423893, PMID:18992931, PMID:25219850, PMID:32708675]. Somatic and germline mutations in SRCAP-complex subunits cause defective H2A.Z deposition that drives epigenetic instability in uterine leiomyoma [PMID:34349258].","teleology":[{"year":2000,"claim":"Established that H2A.Z functions in transcriptional regulation through a chromatin pathway distinct from canonical remodeling/coactivator complexes, raising the question of how it is targeted to genes.","evidence":"Genetic epistasis and locus-specific ChIP at PHO5/GAL1 in S. cerevisiae","pmids":["11081628"],"confidence":"High","gaps":["Did not identify the deposition machinery","Mechanism of locus-specific targeting unresolved"]},{"year":2003,"claim":"Identified the enzymatic basis of H2A.Z deposition, answering how the variant is placed into nucleosomes.","evidence":"Biochemical reconstitution of ATP-dependent H2A-for-H2A.Z exchange by the SWR1 complex plus in vivo ChIP in yeast","pmids":["14645854"],"confidence":"High","gaps":["Which subunit confers H2A.Z specificity not yet defined","Step-by-step exchange mechanism unknown"]},{"year":2005,"claim":"Dissected SWR1 subunit roles and pinpointed H2A.Z C-terminal recognition, defining how the complex distinguishes the variant.","evidence":"Subunit pulldowns, in vitro exchange assays, and H2A.Z C-terminal mutagenesis","pmids":["16299513"],"confidence":"High","gaps":["Atomic basis of Swc2-H2A.Z recognition not resolved","Chaperone contributions unclear"]},{"year":2007,"claim":"Mapped the genomic architecture of H2A.Z nucleosomes, establishing its hallmark positioning flanking nucleosome-free regions at promoters.","evidence":"Deep sequencing of ~322,000 H2A.Z nucleosomes genome-wide in yeast","pmids":["17392789"],"confidence":"High","gaps":["Functional consequence of positioning at inactive genes unclear","No causal link to specific transcriptional outcomes"]},{"year":2007,"claim":"Revealed that H2A.Z carries distinguishing PTMs, with RING1b-mediated monoubiquitylation marking facultative heterochromatin.","evidence":"Fractionation, co-IP, immunofluorescence on the inactive X in mammalian cells","pmids":["17636032"],"confidence":"Medium","gaps":["Functional consequence of ubiquitylation not yet tested","Site of modification not defined here"]},{"year":2008,"claim":"Connected H2A.Z to developmental gene regulation and Polycomb, and to mutual antagonism with DNA methylation, defining its epigenetic context.","evidence":"ChIP-seq/RNAi in mouse ES cells and reciprocal met1/pie1 mutant genomics in Arabidopsis","pmids":["18992931","18815594"],"confidence":"High","gaps":["Molecular basis of H2A.Z-PcG interdependence unresolved","How methylation and H2A.Z exclude each other mechanistically unclear"]},{"year":2009,"claim":"Extended H2A.Z function to inducible mammalian enhancers/promoters, centromere silencing, antisense suppression, and identified acetylation sites that modulate nucleosome stability.","evidence":"ChIP-seq/RNAi at ERα targets (human), genetic epistasis at centromeres and antisense loci (S. pombe), and acetyl-site mass spec/NCP reconstitution","pmids":["19515975","19910462","19693008","19385636"],"confidence":"High","gaps":["How acetylation state is read out in vivo unclear","Centromere role mechanism beyond CENP-C expression not defined"]},{"year":2013,"claim":"Identified specific writers placing methyl and acetyl marks on H2A.Z, linking modifications to differentiation and active transcription.","evidence":"In vitro enzymatic assays, mass spec, and ChIP for SETD6 (K7me1) and KAT2A/GCN5 (H2A.Z.1 acetylation recruiting BRD2)","pmids":["23324626","31527837"],"confidence":"High","gaps":["Reader proteins for K7me1 not identified","Interplay among competing PTMs at a single residue unclear"]},{"year":2014,"claim":"Provided direct mechanistic evidence that H2A.Z lowers the Pol II elongation barrier and demonstrated an in vivo behavioral role in memory.","evidence":"Genome-wide NET-seq with H2A.Z depletion (yeast) and fear-conditioning ChIP/expression (mouse)","pmids":["24606920","25219850"],"confidence":"High","gaps":["How H2A.Z structurally lowers the barrier not resolved here","Memory effect mechanism at gene-level undefined"]},{"year":2015,"claim":"Placed INO80/ANP32E as the H2A.Z removal pathway promoting homologous recombination, and identified BRD2 as an isoform-linked reader.","evidence":"Epistasis co-depletion with HR reporter assays and co-IP/ChIP-seq in human cells","pmids":["26142279","26051178"],"confidence":"High","gaps":["Mechanistic basis of INO80 dimer eviction not yet structural","Isoform-specific BRD2 effects (H2A.Z.2 vs Z.1) need reconciling"]},{"year":2016,"claim":"Solved the structural basis of YL1/Swc2-mediated H2A.Z recognition and defined how methylation (SMYD3 K101me2) and ubiquitylation balance deposition versus removal and Polycomb repression.","evidence":"Crystal structures of YL1-H2A.Z-H2B (Drosophila and human), plus SMYD3 enzymatic/co-IP and H2A.Z.1 K3R3 mutagenesis with BRD2 rescue","pmids":["26974124","26974126","27569210","26804911"],"confidence":"High","gaps":["How modifications are dynamically coordinated in cells unclear","Structural state during full SWR1 catalytic cycle still incomplete"]},{"year":2017,"claim":"Defined the INO80 eviction mechanism, identified the H2A.Z reader PWWP2A, and extended function to cotranscriptional splicing and redundant deposition chaperones.","evidence":"Single-molecule/biochemical INO80 translocation assays, H2A.Z interactome with domain mapping, S. pombe splicing genetics, and Nap1/Chz1 double-deletion analysis","pmids":["28604691","28645917","28446597","28883625"],"confidence":"High","gaps":["How PWWP2A network directs downstream functions unclear","Splicing role mechanism beyond Prp16 pathway undefined"]},{"year":2018,"claim":"Expanded H2A.Z roles to Notch enhancer control, meiotic DSB formation, and gliogenesis via H3K56ac, showing functions across signaling, meiosis, and differentiation.","evidence":"ChIP/co-IP/knockdown at RBP-J enhancers, meiotic DSB and nuclear architecture assays (S. pombe), and ASF1a co-IP/ChIP in neural precursors","pmids":["29986055","29145618","29982651"],"confidence":"Medium","gaps":["Direct vs indirect contributions to each pathway unclear","Single-lab findings without orthogonal confirmation"]},{"year":2019,"claim":"Established H2A.Z as a scaffold for replication-origin licensing and dissected chaperone bioavailability and tissue-specific deposition control.","evidence":"In vitro binding/ChIP-seq/nascent-strand sequencing for SUV420H1-H4K20me2-ORC1, Chz1 crystal structure, and Znhit1-YL1 phosphorylation in intestinal stem cells","pmids":["31875854","31107867","30842416"],"confidence":"High","gaps":["How H2A.Z is restricted to early origins unclear","Coupling of deposition to replication timing not fully resolved"]},{"year":2020,"claim":"Linked H2A.Z structure to function—nucleosome unwrapping, CTCF regulation, isoform-specific compaction, and post-mitotic nuclear reassembly—while showing it is dispensable for transcription in non-dividing cells.","evidence":"MNase-X-ChIP-seq/CTCF CUT&RUN, cryo-EM of H2A.Z.2.2 nucleosome, cell-free nuclear reassembly, and in vivo muscle conditional knockout","pmids":["32392318","33073403","32708675","32266374","32109204"],"confidence":"High","gaps":["Why H2A.Z is dispensable post-mitotically mechanistically unclear","Relationship between unwrapping and CTCF eviction incompletely defined"]},{"year":2021,"claim":"Provided structural and disease-level synthesis: cryo-EM of H2A.Z nucleosomes/fibers explaining dual roles, isoform division of labor in cell division, and SRCAP-mutation-driven H2A.Z loss in uterine leiomyoma.","evidence":"Cryo-EM with C-terminal mutagenesis, isoform-specific siRNA/imaging, Drosophila ZGA knockdown with HiC, and multi-omic primary-tumor sequencing","pmids":["34643712","34423893","34853314","34349258"],"confidence":"High","gaps":["How fiber condensation reconciles with promoter activation unclear","Causal chain from SRCAP mutation to tumorigenesis incomplete"]},{"year":2022,"claim":"Resolved the temporal mechanism of SWR1 deposition and defined TIP60-dependent K7 acetylation, nutrient-responsive deacetylation, and acetylation-dependent epigenetic competence.","evidence":"Three-color single-molecule FRET and ensemble assays (yeast SWR1C), TIP60 knockout/ChIP, TORC1-Rpd3L-Ino80 deacetylation genetics, and Tip60-dependent bivalent gene activation","pmids":["35263135","36396651","35853868","36888706","36417913"],"confidence":"High","gaps":["How discrete ATP steps couple to chaperone handoff in cells unclear","Whether deacetylation directly gates deposition in mammals unconfirmed"]},{"year":2023,"claim":"Defined SUV420H1 structural selectivity for H2A.Z nucleosomes and identified SENP5-mediated deSUMOylation regulating HR repair and radioresistance.","evidence":"Cryo-EM of SUV420H1-H2A.Z-nucleosome with mutagenesis, and SUMO-proteomics/co-IP/HR assays with PDO/PDX models","pmids":["37536340","37684630"],"confidence":"High","gaps":["SUMO site(s) on H2A.Z not fully mapped","Therapeutic implications of SENP5 axis untested clinically"]},{"year":2024,"claim":"Showed that H2A.Z.1 acetylation status bidirectionally controls memory and couples to neuronal alternative splicing, linking specific PTMs to cognitive output.","evidence":"AAV-delivered acetyl-mimic/defective H2A.Z.1 mutants with fear conditioning and RNA/splicing analysis in mouse hippocampus","pmids":["38366138"],"confidence":"Medium","gaps":["Reader machinery translating acetylation into splicing changes unknown","Single-lab in vivo finding without independent replication"]},{"year":null,"claim":"How the full repertoire of H2A.Z post-translational modifications, isoform identity, and reader proteins is integrated to specify activating versus repressive outcomes at individual loci remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model linking PTM combinations to context-specific function","Isoform-specific reader/effector logic only partially mapped","In vivo dynamics of deposition-eviction cycling at single loci undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[31,24,32,23]},{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[30,31]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[22,3,7]}],"localization":[{"term_id":"GO:0000228","term_label":"nuclear chromosome","supporting_discovery_ids":[2,30,31]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[0,3,4]},{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[9,37,45]}],"pathway":[{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[0,1,31]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[22,3,7,27]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[12,39]},{"term_id":"R-HSA-69306","term_label":"DNA Replication","supporting_discovery_ids":[20,21]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[37,28]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[4,29,46]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[49]}],"complexes":["SWR1/SRCAP complex","INO80 complex","TIP60/p400 complex","nucleosome"],"partners":["VPS72","ANP32E","SUV420H1","PWWP2A","BRD2","RING1B","SMYD3","KAT5"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P0C0S5","full_name":"Histone H2A.Z","aliases":[],"length_aa":128,"mass_kda":13.6,"function":"Variant histone H2A which replaces conventional H2A in a subset of nucleosomes. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. May be involved in the formation of constitutive heterochromatin. May be required for chromosome segregation during cell division","subcellular_location":"Nucleus; Chromosome","url":"https://www.uniprot.org/uniprotkb/P0C0S5/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/H2AZ1","classification":"Common Essential","n_dependent_lines":985,"n_total_lines":1208,"dependency_fraction":0.8153973509933775},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000164032","cell_line_id":"CID001835","localizations":[{"compartment":"chromatin","grade":3},{"compartment":"nucleoplasm","grade":2}],"interactors":[{"gene":"H2AFY","stoichiometry":10.0},{"gene":"UBB;UBC;RPS27A;UBA52","stoichiometry":10.0},{"gene":"H2AFZ;H2AFV","stoichiometry":10.0},{"gene":"PARP1","stoichiometry":10.0},{"gene":"HIST1H1C","stoichiometry":10.0},{"gene":"RBBP7","stoichiometry":10.0},{"gene":"CBX3","stoichiometry":10.0},{"gene":"RBBP4","stoichiometry":10.0},{"gene":"HIST1H4A","stoichiometry":10.0},{"gene":"XRCC6","stoichiometry":4.0}],"url":"https://opencell.sf.czbiohub.org/target/CID001835","total_profiled":1310},"omim":[{"mim_id":"620008","title":"H2A.Z VARIANT HISTONE 2; H2AZ2","url":"https://www.omim.org/entry/620008"},{"mim_id":"606265","title":"E1A-BINDING PROTEIN, 400-KD; EP400","url":"https://www.omim.org/entry/606265"},{"mim_id":"142763","title":"H2A.Z VARIANT HISTONE 1; H2AZ1","url":"https://www.omim.org/entry/142763"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nucleoplasm","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/H2AZ1"},"hgnc":{"alias_symbol":["H2A.Z"],"prev_symbol":["H2AZ","H2AFZ"]},"alphafold":{"accession":"P0C0S5","domains":[{"cath_id":"1.10.20.10","chopping":"20-111","consensus_level":"medium","plddt":97.7566,"start":20,"end":111}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P0C0S5","model_url":"https://alphafold.ebi.ac.uk/files/AF-P0C0S5-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P0C0S5-F1-predicted_aligned_error_v6.png","plddt_mean":90.38},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=H2AZ1","jax_strain_url":"https://www.jax.org/strain/search?query=H2AZ1"},"sequence":{"accession":"P0C0S5","fasta_url":"https://rest.uniprot.org/uniprotkb/P0C0S5.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P0C0S5/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P0C0S5"}},"corpus_meta":[{"pmid":"14645854","id":"PMC_14645854","title":"ATP-driven exchange of histone H2AZ variant catalyzed by SWR1 chromatin remodeling complex.","date":"2003","source":"Science (New York, N.Y.)","url":"https://pubmed.ncbi.nlm.nih.gov/14645854","citation_count":1032,"is_preprint":false},{"pmid":"11893489","id":"PMC_11893489","title":"Histone H2A variants H2AX and H2AZ.","date":"2002","source":"Current opinion in genetics & development","url":"https://pubmed.ncbi.nlm.nih.gov/11893489","citation_count":592,"is_preprint":false},{"pmid":"17392789","id":"PMC_17392789","title":"Translational and rotational settings of H2A.Z nucleosomes across the Saccharomyces cerevisiae genome.","date":"2007","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/17392789","citation_count":548,"is_preprint":false},{"pmid":"18815594","id":"PMC_18815594","title":"Histone H2A.Z and DNA methylation are mutually antagonistic chromatin 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androgen receptor-mediated effects on fear memory.","date":"2020","source":"Neurobiology of learning and memory","url":"https://pubmed.ncbi.nlm.nih.gov/32916283","citation_count":15,"is_preprint":false},{"pmid":"30651935","id":"PMC_30651935","title":"Metformin alters H2A.Z dynamics and regulates androgen dependent prostate cancer progression.","date":"2018","source":"Oncotarget","url":"https://pubmed.ncbi.nlm.nih.gov/30651935","citation_count":15,"is_preprint":false},{"pmid":"24957674","id":"PMC_24957674","title":"Yeast X-chromosome-associated protein 5 (Xap5) functions with H2A.Z to suppress aberrant transcripts.","date":"2014","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/24957674","citation_count":15,"is_preprint":false},{"pmid":"38366138","id":"PMC_38366138","title":"Role of the histone variant H2A.Z.1 in memory, transcription, and alternative splicing is mediated by lysine modification.","date":"2024","source":"Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/38366138","citation_count":15,"is_preprint":false},{"pmid":"25765960","id":"PMC_25765960","title":"H2A.Z marks antisense promoters and has positive effects on antisense transcript levels in budding yeast.","date":"2015","source":"BMC genomics","url":"https://pubmed.ncbi.nlm.nih.gov/25765960","citation_count":15,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":42410,"output_tokens":13243,"usd":0.162938,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":24855,"output_tokens":6304,"usd":0.140937,"stage2_stop_reason":"end_turn"},"total_usd":0.303875,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2003,\n      \"finding\": \"The SWR1 complex, with Swr1 (a Swi2/Snf2-related ATPase) as its catalytic core, catalyzes ATP-dependent exchange of nucleosomal histone H2A for H2A.Z in nucleosome arrays. Swr1 is required for deposition of H2A.Z at specific chromosome locations in vivo.\",\n      \"method\": \"Biochemical reconstitution of histone exchange activity; in vivo ChIP; genetic analysis in S. cerevisiae\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — biochemical reconstitution of ATP-dependent exchange in vitro, corroborated by in vivo ChIP and genetic epistasis, foundational study widely replicated\",\n      \"pmids\": [\"14645854\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Within the SWR1 complex, Swc2 binds directly to H2A.Z and is essential for its transfer into nucleosomes. Swc6 and Arp6 are required for Swc2 association and nucleosome binding; Swc5 and Yaf9 are required for H2A.Z transfer but not for H2A.Z or nucleosome binding. The C-terminal alpha-helix of H2A.Z is crucial for recognition by SWR1.\",\n      \"method\": \"Biochemical dissection of SWR1 subunit interactions; pulldown/co-IP; in vitro histone exchange assay; mutagenesis of H2A.Z C-terminal helix\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple orthogonal biochemical methods including mutagenesis and in vitro exchange assays in a single focused study\",\n      \"pmids\": [\"16299513\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"H2A.Z nucleosomes occupy a single predominant rotational setting and multiple translational settings in the S. cerevisiae genome, flanking nucleosome-free regions at promoters of both active and inactive genes, with transcription factor binding sites rotationally exposed near nucleosome borders.\",\n      \"method\": \"Deep sequencing of 322,000 individual H2A.Z-containing nucleosomes (genome-wide nucleosome positioning)\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — comprehensive genome-wide sequencing with median 4-bp resolution, providing foundational genomic architecture data replicated in subsequent studies\",\n      \"pmids\": [\"17392789\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"H2A.Z regulates gene transcription in S. cerevisiae; deletion of H2A.Z strongly increases the requirement for SNF/SWI and SAGA remodeling complexes (synthetic genetic interaction). H2A.Z is preferentially crosslinked to intergenic DNA at PHO5 and GAL1 loci, and this association changes with transcriptional activation, placing H2A.Z in a distinct pathway from SNF/SWI and SAGA for chromatin-based transcriptional regulation.\",\n      \"method\": \"Genetic epistasis (synthetic lethality/sick interactions); chromatin immunoprecipitation (ChIP) at specific loci in S. cerevisiae\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis plus direct ChIP localization, independently replicated across multiple subsequent studies\",\n      \"pmids\": [\"11081628\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"H2A.Z occupies promoters of developmentally important genes in mouse ES cells in a manner similar to Polycomb group protein Suz12. H2A.Z and PcG protein occupancy is interdependent at promoters (RNAi depletion of H2A.Z reduces PcG occupancy and vice versa), and H2A.Z is necessary for ES cell differentiation and lineage commitment.\",\n      \"method\": \"Genome-wide ChIP-seq; RNAi knockdown with gene expression and differentiation assays in mouse ES cells\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genome-wide ChIP-seq combined with RNAi functional knockdown and differentiation readouts in a focused study\",\n      \"pmids\": [\"18992931\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"A fraction of mammalian H2A.Z is monoubiquitylated; on the inactive X chromosome the majority of H2A.Z is ubiquitylated. Monoubiquitylation of H2A.Z is mediated by the RING1b E3 ligase of the human Polycomb complex, distinguishing H2A.Z associated with facultative heterochromatin from euchromatin-associated H2A.Z.\",\n      \"method\": \"Biochemical fractionation; co-immunoprecipitation; immunofluorescence; identification of RING1b as the E3 ligase\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP and fractionation identify RING1b as writer, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"17636032\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"DNA methylation and H2A.Z deposition are mutually antagonistic in Arabidopsis: regions of DNA methylation are quantitatively deficient in H2A.Z. Mutation of MET1 DNA methyltransferase causes losses of H2A.Z at sites gaining methylation and gains of H2A.Z at sites losing methylation; mutation of PIE1 (SWR1 complex subunit) leads to genome-wide hypermethylation. This demonstrates that DNA methylation excludes H2A.Z and H2A.Z protects genes from DNA methylation.\",\n      \"method\": \"ChIP-chip; genetic analysis of met1 and pie1 mutants with genome-wide methylation and H2A.Z profiling in Arabidopsis\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal genetic and genomic analyses across two mutants, later replicated in mammals\",\n      \"pmids\": [\"18815594\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"H2A.Z incorporation into promoter chromatin of estrogen receptor (ERα) target genes occurs upon gene induction in a cyclic pattern, mediated by the p400 complex. Cellular depletion of H2A.Z or p400 causes severe defects in estrogen signaling and estrogen-specific cell proliferation. H2A.Z incorporation allows nucleosomes to adopt preferential translational positions at the TFF1 promoter and is essential for estrogen-responsive enhancer function.\",\n      \"method\": \"ChIP-seq; RNAi knockdown; gene expression analysis; nucleosome positioning assay in human cells\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ChIP-seq, RNAi functional knockdown, nucleosome positioning, and enhancer assays using multiple orthogonal methods\",\n      \"pmids\": [\"19515975\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"H2A.Z loaded at 5' ends of genes by the Swr1 complex containing a JmjC domain protein mediates suppression of antisense transcripts in fission yeast. H2A.Z is partially redundant with the Clr4-containing heterochromatin complex and RNAi component Ago1 in suppressing antisense transcripts that are normally degraded by the exosome.\",\n      \"method\": \"Genetic epistasis (H2A.Z/Clr4/Ago1 double and triple mutant analysis); ChIP; RNA analysis in S. pombe\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with multiple combinatorial mutants plus ChIP localization, Nature-level study\",\n      \"pmids\": [\"19693008\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"H2A.Z deposition in fission yeast requires a novel JmjC domain protein Msc1 as a component of the Swr1 complex. Loss of Msc1, Swr1, or H2A.Z results in loss of centromere silencing and defective chromosome segregation. H2A.Z is required for expression of the centromere protein CENP-C, and overexpression of CENP-C rescues centromere silencing defects associated with H2A.Z loss.\",\n      \"method\": \"Genetic analysis; ChIP; epistasis rescue experiments in S. pombe\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with rescue experiment, single lab\",\n      \"pmids\": [\"19910462\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"SETD6 lysine methyltransferase monomethylates H2A.Z at lysine 7 (H2AZK7me1). This modification increases upon differentiation of mouse embryonic stem cells; H2AZK7me1 and H3K27me3 co-occupy transcription start sites of differentiation marker genes. Depletion of Setd6 leads to cellular differentiation and compromised self-renewal in mESCs.\",\n      \"method\": \"In vitro methyltransferase assay; mass spectrometry; ChIP; siRNA knockdown in mESCs\",\n      \"journal\": \"Epigenetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro enzymatic assay identifies SETD6 as writer plus ChIP and functional knockdown, single lab\",\n      \"pmids\": [\"23324626\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"H2A.Z.2 (encoded by H2AFV) interacts with BRD2 bromodomain protein. H2A.Z.2 controls transcriptional output of E2F target genes in melanoma; BRD2 binding to H2A.Z.2-regulated genes is dependent on H2A.Z.2 levels. H2A.Z.2 deficiency sensitizes melanoma cells to chemotherapy and targeted therapies.\",\n      \"method\": \"Co-immunoprecipitation; ChIP-seq; RNAi knockdown; integrated genomic analyses in melanoma cells\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP and ChIP-seq in a single lab study; note this concerns H2A.Z.2 (H2AFV), not H2A.Z.1/H2AFZ\",\n      \"pmids\": [\"26051178\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"H2A.Z in human cells is rapidly removed from chromatin flanking DNA damage by the INO80 remodeling complex. The histone chaperone ANP32E also promotes homologous recombination and works in the same pathway as INO80 for H2A.Z removal. The HR defect in INO80- or ANP32E-depleted cells is rescued by co-depletion of H2A.Z, demonstrating that H2A.Z removal from chromatin is the primary function of INO80 and ANP32E in promoting HR.\",\n      \"method\": \"ChIP; epistasis rescue (co-depletion); siRNA knockdown; HR reporter assay in human cells\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — epistasis rescue with co-depletion and HR functional assay, multiple orthogonal methods establishing pathway placement\",\n      \"pmids\": [\"26142279\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"The crystal structure of Drosophila YL1 (Swc2) H2A.Z-binding domain (dYL1-Z) in complex with H2A.Z-H2B dimer at 1.9-Å resolution reveals a whip-like structure that wraps over H2A.Z-H2B. Preferential recognition is conferred by three residues in loop 2, the hyperacidic patch, and the extended αC helix of H2A.Z. This domain is essential for H2A.Z deposition in vivo and SRCAP(SWR1)-catalyzed replacement in vitro.\",\n      \"method\": \"Crystal structure (1.9 Å); in vitro histone replacement assay; in vivo deposition assay; mutagenesis\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution crystal structure with mutagenesis and functional in vitro/in vivo validation, two independent structural papers published simultaneously\",\n      \"pmids\": [\"26974124\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"YL1 is a specific H2A.Z-deposition chaperone in metazoans. Crystal structure at 2.7 Å of the human YL1-H2A.Z-H2B complex shows YL1 binding triggers extension of the H2A.Z αC helix and contacts the extended acidic patch and entire DNA-binding surface of H2A.Z-H2B. Only four amino acid substitutions in H2A are sufficient to create an H2A.Z-like interface recognized by YL1.\",\n      \"method\": \"Crystal structure (2.7 Å); biochemical binding assays; mutagenesis\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution crystal structure with mutagenesis establishing molecular basis for H2A.Z-specific recognition\",\n      \"pmids\": [\"26974126\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"SMYD3 methyltransferase dimethylates H2A.Z.1 at lysine 101 (H2A.Z.1K101me2), which increases H2A.Z.1 stability by preventing binding to the removal chaperone ANP32E and facilitating interaction with histone H3. SMYD3 and H2A.Z.1K101me2 co-localize at the cyclin A1 promoter, activating its expression and G1-S progression.\",\n      \"method\": \"In vitro methyltransferase assay; co-immunoprecipitation; ChIP; cyclin A1 rescue in mouse model; microarray\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro enzymatic assay plus co-IP and ChIP, single lab\",\n      \"pmids\": [\"27569210\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"H2A.Z.1 monoubiquitylation (H2A.Z.1ub) at PRC1 target residues is required to maintain Polycomb binding and repress bivalent genes in mESCs. Loss of monoubiquitylation (K3R3 mutant) leads to de-repression of bivalent genes and faulty lineage commitment. Tandem bromodomain protein BRD2 is enriched in H2A.Z.1 chromatin and is gained at de-repressed promoters in H2A.Z.1(K3R3) mESCs; BRD2 inhibition restores gene silencing, revealing an antagonistic relationship between H2A.Z.1ub and BRD2.\",\n      \"method\": \"Mutagenesis (H2A.Z.1K3R3); ChIP; quantitative proteomics; BRD2 inhibition rescue experiment in mESCs\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — mutagenesis, ChIP, quantitative proteomics, and pharmacological rescue across multiple orthogonal methods in a single study\",\n      \"pmids\": [\"26804911\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Unlike other chromatin remodelers that translocate at the H3-H4 interface, INO80 translocates along DNA at the H2A-H2B interface of nucleosomes and persistently displaces DNA from H2A-H2B, generating DNA torsional strain near the entry site. This unique translocation mechanism drives both nucleosome mobilization and selective exchange of H2A.Z-H2B dimers for H2A-H2B without additional histone chaperones. INO80 translocates and mobilizes H2A.Z-containing nucleosomes more efficiently than H2A-containing nucleosomes.\",\n      \"method\": \"Biochemical translocation assays; single-molecule analysis; histone exchange assays in vitro; mutant analysis\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with single-molecule analysis and mutagenesis distinguishing INO80 mechanism from other remodelers\",\n      \"pmids\": [\"28604691\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"PWWP2A is a novel H2A.Z-nucleosome binding protein identified by H2A.Z interactome analysis. PWWP2A binds H2A.Z-containing nucleosomes via multivalent interaction (two internal regions for H2A.Z-specificity/nucleosome contact, PWWP domain for DNA binding). The C-terminal tail of H2A.Z mediates PWWP2A recruitment. PWWP2A depletion impairs cell proliferation via mitotic delay and causes neural crest cell defects in Xenopus.\",\n      \"method\": \"Co-immunoprecipitation interactome; domain mapping; genome-wide ChIP-seq; siRNA knockdown; Xenopus knockdown\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — comprehensive interactome plus ChIP-seq and functional knockdown in multiple systems, single lab\",\n      \"pmids\": [\"28645917\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"H2A.Z is actively exchanged in the hippocampus and cortex in response to fear conditioning. H2A.Z exchange mediates gene expression and restrains formation of recent and remote memory. H2A.Z acts as a negative regulator of hippocampal consolidation and systems consolidation.\",\n      \"method\": \"Fear conditioning behavioral paradigm; ChIP; gene expression analysis in mouse hippocampus and cortex\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP demonstrating active exchange plus behavioral readout, single lab\",\n      \"pmids\": [\"25219850\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"H2A.Z-containing nucleosomes are enriched with H4K20me2 and bound ORC in HeLa cells. H2A.Z-nucleosomes bind directly to SUV420H1, promoting H4K20me2 deposition, which is required for ORC1 binding at replication origins. Depletion of H2A.Z reduces H4K20me2, ORC1 binding, and nascent-strand signals genome-wide, impairing early replication origin licensing and activation.\",\n      \"method\": \"In vitro binding assays; ChIP-seq; nascent strand sequencing; H2A.Z depletion in HeLa cells; genome-wide co-localization\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro direct binding plus genome-wide ChIP-seq and functional depletion, multiple orthogonal methods\",\n      \"pmids\": [\"31875854\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Cryo-EM structure of SUV420H1 bound to H2A.Z-nucleosome reveals direct interaction with H4 N-terminal tail (H4 residues 1-24 forming a lasso-shaped structure projecting H4K20 into the catalytic center), DNA, and nucleosome acidic patch. The SUV420H1 KR loop (residues 214-223) lies close to H2A.Z-specific residues D97/S98 and is crucial for preferential recognition of H2A.Z-nucleosome over canonical H2A-nucleosome.\",\n      \"method\": \"Cryo-EM structure; in vitro methyltransferase assay; mutagenesis; in vivo analysis\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structure with mutagenesis and in vitro/in vivo functional validation\",\n      \"pmids\": [\"37536340\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"The +1 nucleosome is a major barrier to elongating RNAPII for essentially all genes. The extent of this barrier anticorrelates with enrichment of H2A.Z: depletion of H2A.Z from a nucleosome position results in a higher barrier to RNAPII. This shows H2A.Z incorporation at the +1 nucleosome reduces the transcriptional barrier.\",\n      \"method\": \"Genome-wide native elongating transcript sequencing (NET-seq) at nucleotide resolution; H2A.Z depletion in yeast\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genome-wide direct measurement of RNAPII stalling combined with H2A.Z depletion functional experiment\",\n      \"pmids\": [\"24606920\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"H2A.Z.2.2, an alternatively spliced variant of H2A.Z, binds to TIP60 and SRCAP chaperone complexes and is actively deposited into chromatin in a replication-independent manner. Its unique C-terminus causes major structural destabilization of nucleosomes as demonstrated by biochemical fractionation, FRAP, size exclusion chromatography, single-molecule FRET, and molecular dynamics simulations.\",\n      \"method\": \"Co-immunoprecipitation with TIP60/SRCAP complexes; FRAP; size exclusion chromatography; single-molecule FRET; molecular dynamics simulations; deletion mutant analysis\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple independent in vitro and in vivo methods (FRET, FRAP, biochemistry, MD) consistently demonstrating nucleosome destabilization\",\n      \"pmids\": [\"22467210\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Acetylation sites of vertebrate H2A.Z (K4, K7, K11, K13, K15) were identified from chicken erythrocytes. H2A.Z stabilizes the nucleosome core particle (NCP) regardless of its acetylation state. Acetylated H2A.Z variants act synergistically with other acetylated core histones to alter NCP conformation. Heteromorphic NCPs containing both H2A.Z and H2A are slightly destabilized only in the presence of acetylation.\",\n      \"method\": \"Mass spectrometry (acetylation site identification); NCP reconstitution with acetylated histones and H2A.Z(K/Q) acetylation mimic mutants; biochemical stability assays\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with mutagenesis and NCP stability assays, single lab\",\n      \"pmids\": [\"19385636\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Znhit1, a subunit of the SRCAP complex, incorporates H2A.Z into TSS regions of genes governing Lgr5+ intestinal stem cell fate (Lgr5, Tgfb1, Tgfbr2). Mechanistically, Znhit1 promotes H2A.Z incorporation by controlling phosphorylation of the H2A.Z chaperone YL1, enhancing YL1-H2A.Z interaction.\",\n      \"method\": \"Conditional knockout mouse; ChIP-seq; co-immunoprecipitation; phosphorylation analysis; intestinal stem cell functional assays\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional KO with ChIP-seq and co-IP mechanism, single lab\",\n      \"pmids\": [\"30842416\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"H2A.Z deposition and acetylation by the TRRAP/p400/Tip60 complex (which physically associates with transcription factor RBP-J at Notch-dependent enhancers) is required for tight control of canonical Notch target gene activation. Tip60 acetylates H2A.Z when targeted to RBP-J-bound enhancers, upregulating Notch target genes. Drosophila homologs of Tip60, p400, and H2A.Z modulate Notch signaling in vivo.\",\n      \"method\": \"ChIP; co-immunoprecipitation; siRNA knockdown; in vivo Drosophila genetic analysis; gene expression assays\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP, ChIP, and in vivo genetic validation across two organisms, single lab\",\n      \"pmids\": [\"29986055\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"KAT2A (GCN5) acetylates H2A.Z.1 at promoters of transactivated genes. The DNA repair complex XPC-RAD23-CEN2 interacts with both H2A.Z and KAT2A, recruiting KAT2A to promoters to license H2A.Z.1 acetylation. KAT2A selectively acetylates H2A.Z.1 but not H2A.Z.2 in vitro; alanine-14 in H2A.Z.2 inhibits KAT2A activity. Acetyl-H2A.Z.1 recruits BRD2 to promote RNAPII recruitment.\",\n      \"method\": \"In vitro acetyltransferase assay; co-immunoprecipitation; ChIP; mutagenesis (non-acetylable H2A.Z.1); RNAPII recruitment assay\",\n      \"journal\": \"Nature chemical biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro enzymatic assay with mutagenesis plus ChIP and co-IP, identifying writer and reader in one study\",\n      \"pmids\": [\"31527837\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"TIP60 (KAT5) is essential for acetylation of H2A.Z specifically at lysine 7 in human and mouse cells. Loss of TIP60 causes complete cell growth arrest with failure of chromosome alignment during mitosis. This growth arrest is independent of p53, INK4A, and ARF tumor suppressors.\",\n      \"method\": \"Inducible Cre-recombinase and CRISPR/Cas9 deletion of TIP60; ChIP; RNA-seq; cell cycle analysis; live imaging of mitosis\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO with ChIP confirming H2A.Z K7 acetylation loss plus functional phenotypic readouts, single lab\",\n      \"pmids\": [\"35853868\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Tip60 acetyltransferase acetylates H2A.Z, and loss of H2A.Z acetylation interferes with H3K4me3 deposition and activation of bivalent, lineage-restricted genes during neuronal fate specification. H2A.Z acetylation does not affect chromatin accessibility but is required for epigenetic competence (bivalent chromatin activation) during cell lineage transition.\",\n      \"method\": \"Proteomics; genetic depletion of Tip60; ChIP-seq; ATAC-seq; RNA-seq; neuronal differentiation assays\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic depletion with ChIP-seq, ATAC-seq, and RNA-seq, single lab\",\n      \"pmids\": [\"36417913\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"H2A.Z nucleosomes are more enriched in unwrapped states compared with canonical nucleosomes in mouse ES cells, as measured by MNase-X-ChIP-seq. Depletion of H2A.Z results in decreased unwrapping of H3.3 nucleosomes and increased CTCF binding, demonstrating that H2A.Z regulates nucleosome unwrapping in vivo and that its transcriptional and CTCF-regulatory functions correlate with nucleosome unwrapping states.\",\n      \"method\": \"MNase-X-ChIP-seq; re-ChIP; CTCF CUT&RUN; H2A.Z depletion in mouse ES cells\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — novel sequencing method plus functional depletion with CTCF binding readout, single lab\",\n      \"pmids\": [\"32392318\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Cryo-EM structures of H2A.Z-containing nucleosomes and chromatin fibers show that H2A.Z incorporation increases mobility of DNA termini in nucleosomes (due to its shorter C-terminus) while simultaneously enabling nucleosome arrays to form a more regular and condensed chromatin fiber. This structural basis provides a mechanistic explanation for H2A.Z's dual activating and repressive transcriptional roles.\",\n      \"method\": \"Cryo-EM structure of nucleosome and chromatin fiber; deletion mutant analysis of H2A.Z C-terminus\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structures of both nucleosome and chromatin fiber with mutagenesis validation\",\n      \"pmids\": [\"34643712\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Cryo-EM structure of H2A.Z.2.2-containing nucleosome (Z.2.2-NCP) shows it compacts ~125 bp of DNA (less than canonical ~147 bp). Nineteen H2A.Z.2.2-specific residues including a ROF ('regulating-octamer-folding') sequence are responsible for nucleosome opening and also required for SWR1-dependent histone replacement.\",\n      \"method\": \"Cryo-EM structure; MNase digestion assay; mutagenesis of ROF sequence; SWR1-dependent replacement assay\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — cryo-EM structure with mutagenesis and functional assay for SWR1-mediated replacement\",\n      \"pmids\": [\"33073403\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Single-molecule FRET analysis of SWR1-mediated H2A.Z deposition reveals three ATP-dependent phases: (1) a priming step involving transient DNA unwrapping and histone octamer deformations; (2) rapid loss of H2A-H2B; (3) release of displaced H2A-H2B from the SWR1-nucleosome complex, facilitated by histone chaperones. SWR1 intrinsically senses long-linker DNA to preferentially exchange H2A.Z on the distal face of asymmetrically positioned nucleosomes.\",\n      \"method\": \"Three-color single-molecule FRET; ensemble biochemical assays; real-time single nucleosome remodeling imaging\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — single-molecule reconstitution resolving mechanism with temporal precision across multiple ATP-dependent steps\",\n      \"pmids\": [\"35263135\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"SWR1C (yeast SWR1 complex) uses multiple ATP-dependent steps for H2A.Z deposition, identified by single-molecule and ensemble methods: an initial priming step (transient DNA unwrapping and octamer deformations), rapid H2A loss, and subsequent H2A/H2B release from the H2A.Z nucleosomal product. Rates of priming and H2A/H2B dimer release are sensitive to ATP concentration.\",\n      \"method\": \"Single-molecule real-time analysis of nucleosome remodeling; ensemble histone exchange assays; ATP concentration titrations\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — single-molecule reconstitution and ensemble biochemistry identifying discrete mechanistic steps\",\n      \"pmids\": [\"36396651\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"The crystal structure of the Chz1-H2A.Z-H2B ternary complex reveals that Chz1 uses two distinct structural domains: the middle region (Chz1-M) directly interacts with H2A.Z-specific residues Gly98 and Ala57 for modest preferential binding; the C-terminal region (Chz1-C) harbors a DEF/Y motif engaging an arginine finger and hydrophobic pocket in H2A.Z-H2B, enhancing binding preference. Chz1 facilitates SWR1-mediated H2A.Z deposition by controlling bioavailability of free H2A.Z.\",\n      \"method\": \"Crystal structure; biochemical binding assays; mutagenesis; in vitro SWR1 histone deposition assay\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure with mutagenesis and in vitro functional deposition assay\",\n      \"pmids\": [\"31107867\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Nap1 and Chz1 have redundant roles as histone chaperones for H2A.Z deposition in S. cerevisiae. They use different H2A.Z surface residues for interaction. Loss of either Nap1 or Chz1 alone causes mild H2A.Z deposition defects, but deletion of both results in significant reduction of H2A.Z at promoters and heterochromatin spreading.\",\n      \"method\": \"Structural modeling; molecular dynamics simulations; mutagenesis; ChIP; genetic double deletion analysis in S. cerevisiae\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — genetic epistasis with ChIP and computational structural modeling, single lab\",\n      \"pmids\": [\"28883625\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"H2A.Z.1 and H2A.Z.2 have non-redundant functions in cell division. H2A.Z.1 regulates expression of cell cycle genes (Myc, Ki-67) and its depletion leads to G1 arrest and cellular senescence. H2A.Z.2, in a transcription-independent manner, is essential for centromere integrity and sister chromatid cohesion regulation, playing a key role in chromosome segregation.\",\n      \"method\": \"Isoform-specific siRNA depletion; cell cycle analysis; live-cell imaging; ChIP-seq; RNA-seq in human cells\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — isoform-specific depletion with cell cycle and chromosome segregation readouts, single lab\",\n      \"pmids\": [\"34423893\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"H2A.Z.1 and H2A.Z.2 have specific interactors (identified by mass spectrometry) that can mediate functional antagonism. They can replace each other at transcription start sites and regulate both distinct and overlapping gene sets in a context-dependent manner. The balance between the two isoforms at promoters critically regulates specific gene expression.\",\n      \"method\": \"Endogenously-tagged protein immunoprecipitation; mass spectrometry; RNA-seq; ChIP-seq in human cells\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — endogenous tagging with mass spectrometry and genome-wide analysis, single lab\",\n      \"pmids\": [\"32109204\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"SENP5 deSUMOylates H2A.Z, and this modification regulates homologous recombination-mediated DNA damage repair. The SUMOylation balance of H2A.Z modulates HR repair and cancer radioresistance. H2A.Z was identified as a SENP5 deSUMOylation substrate by SUMO-proteomic mass spectrometry and co-immunoprecipitation.\",\n      \"method\": \"SUMO-proteomic mass spectrometry; co-immunoprecipitation; HR reporter assay; siRNA knockdown; PDO and PDX models\",\n      \"journal\": \"Journal of experimental & clinical cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mass spectrometry identification plus co-IP and functional HR assay, single lab\",\n      \"pmids\": [\"37684630\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"TORC1 activates the Rpd3L histone deacetylase complex to deacetylate H2A.Z, blocking its deposition into chromatin at autophagy-related gene promoters. Simultaneously, Rpd3L deacetylates the chromatin remodeler Ino80 at K929, stabilizing it and enabling H2A.Z eviction from autophagy genes. This TORC1-Rpd3L-H2A.Z axis represses autophagy-related gene transcription under nutrient-rich conditions.\",\n      \"method\": \"Biochemical deacetylase assays; co-immunoprecipitation; ChIP; genetic epistasis; rapamycin treatment in yeast\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — biochemical assays plus genetic epistasis and ChIP, single lab\",\n      \"pmids\": [\"36888706\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"VPS72/YL1 mediates H2A.Z deposition required for nuclear reassembly after mitosis. Depletion of VPS72 or H2A.Z by siRNA or in vitro depletion results in malformed and nonfunctional nuclei. VPS72 functions outside of the SRCAP and EP400 remodeling complexes for this specific H2A.Z deposition activity.\",\n      \"method\": \"Cell-free nuclear reassembly assay; siRNA knockdown; live-cell imaging; biochemical fractionation\",\n      \"journal\": \"Cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-free reconstitution assay plus live-cell imaging and siRNA, single lab\",\n      \"pmids\": [\"32708675\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"H2A.Z promotes cotranscriptional splicing of suboptimal introns in S. pombe. H2A.Z and Swr1 ATPase are required during temperature stress for efficient splicing of introns with nonconsensus splice sites. Mutating affected splice sites to consensus suppresses the H2A.Z requirement for splicing of that intron. Overexpression of splicing ATPase Prp16 suppresses growth and splicing defects of H2A.Z mutants, placing H2A.Z upstream of Prp16 in a pathway promoting weak intron recognition.\",\n      \"method\": \"Epistatic miniarray profiles (EMAP); splicing microarray; splice site mutagenesis; genetic suppression by Prp16 overexpression in S. pombe\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with splice-site mutagenesis rescue and splicing microarray, single lab\",\n      \"pmids\": [\"28446597\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"H2A.Z depletion in terminally differentiated post-mitotic muscle cells in vivo shows that H2A.Z is dispensable for maintaining or activating transcription in the absence of cell division, as shown by ChIP-seq, RNA-seq, and ATAC-seq. H2A.Z enrichment at active promoters is a marker but not a driver of transcription in post-mitotic cells.\",\n      \"method\": \"In vivo conditional H2A.Z knockout in post-mitotic muscle; ChIP-seq; RNA-seq; ATAC-seq\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo conditional KO with genome-wide readouts; this is a negative mechanistic finding (H2A.Z dispensable for transcription in post-mitotic cells), single lab\",\n      \"pmids\": [\"32266374\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"In Drosophila embryos, H2A.Z enrichment at transcription start sites precedes ZGA and RNA Pol II loading. In vivo knockdown of Domino (H2A.Z chaperone/ATPase) reduces H2A.Z deposition at TSS, causes global downregulation of housekeeping genes at ZGA, and compromises establishment of 3D chromatin structure.\",\n      \"method\": \"GRO-seq; HiC; ChIP-seq; in vivo RNAi knockdown in Drosophila embryos\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — GRO-seq, HiC, ChIP-seq, and in vivo knockdown, single lab\",\n      \"pmids\": [\"34853314\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"H2A.Z promotes meiotic DNA double-strand break formation in fission yeast. In H2A.Z-lacking mutants, multiple proteins involved in DSB formation (including Spo11 homolog and its regulators) show reduced chromatin association, and nuclei are more compact. H2A.Z promotes DSB formation by modulating chromosome architecture to enhance interaction between DSB-related proteins and cohesin-loaded chromatin.\",\n      \"method\": \"ChIP; meiotic DSB assay; nuclear architecture analysis; genetic analysis in S. pombe\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP and DSB functional assay with nuclear architecture analysis, single lab\",\n      \"pmids\": [\"29145618\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"H2A.Z.1 regulates gliogenesis by cooperating with histone chaperone ASF1a to regulate H3K56 acetylation (H3K56ac), which in turn directly affects expression of FOLR1 (folate receptor 1). FOLR1 participates in gliogenesis through the JAK-STAT signaling pathway.\",\n      \"method\": \"siRNA knockdown; ChIP; RNA-seq; co-immunoprecipitation with ASF1a; neural precursor cell differentiation assays\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP, ChIP, and differentiation functional assays, single lab\",\n      \"pmids\": [\"29982651\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The DREAM complex (containing C. elegans lin-35/Rb homolog) promotes high gene-body H2A.Z (HTZ-1) levels at target genes. In lin-35 mutants, DREAM targets show reduced gene body H2A.Z and increased expression. Many DREAM targets are also upregulated in htz-1/H2A.Z mutants, indicating that gene body H2A.Z plays a repressive role at DREAM target genes.\",\n      \"method\": \"ChIP-seq; genetic epistasis (lin-35 and htz-1 mutants); RNA-seq in C. elegans\",\n      \"journal\": \"Genes & development\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP-seq with genetic epistasis in two mutant backgrounds, single lab\",\n      \"pmids\": [\"25737279\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"The role of H2A.Z.1 in memory depends on its acetylation status: acetyl-mimic H2A.Z.1 (K4/7/11Q) improves memory, while acetyl-defective H2A.Z.1 (K4/7/11A) impairs memory. H2A.Z.1KA preferentially affects genes involved in synaptic function. H2A.Z.1 depletion or expression of lysine mutants influences alternative splicing of neuronal genes, revealing that H2A.Z.1 regulates both gene expression and splicing in neurons through post-translational modifications.\",\n      \"method\": \"AAV-mediated overexpression of acetyl-mimic and acetyl-defective H2A.Z.1 mutants; fear conditioning behavioral assays; RNA-seq; splicing analysis in mouse hippocampus\",\n      \"journal\": \"Neuropsychopharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — acetylation-mimic/defective mutagenesis in vivo with behavioral and transcriptomic readouts, single lab\",\n      \"pmids\": [\"38366138\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Somatic mutations in SRCAP complex subunit genes cause defective H2A.Z deposition in uterine leiomyomas. In these tumors, H2A.Z loss at TSS is associated with increased chromatin accessibility and upregulation of bivalent embryonic stem cell genes. Germline mutations in SRCAP members YEATS4 and ZNHIT1 predispose to uterine leiomyoma through epigenetic instability caused by deficient H2A.Z deposition.\",\n      \"method\": \"Whole-genome sequencing; ATAC-seq; ChIP-seq; HiChIP; RNA-seq of primary tumor tissues\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — comprehensive multi-omic analysis of primary human tissues establishing mechanistic connection between SRCAP mutations, H2A.Z deposition defects, and chromatin/gene expression changes\",\n      \"pmids\": [\"34349258\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"H2A.Z (H2AZ1/H2AFZ) is a conserved histone H2A variant that is incorporated into nucleosomes flanking gene promoters, enhancers, and regulatory elements in an ATP-dependent manner by the SWR1/SRCAP multi-subunit remodeling complex (with YL1/Swc2 serving as the specific H2A.Z recognition subunit via a whip-like structural domain engaging H2A.Z's hyperacidic patch and extended αC helix), while the INO80 complex performs the reverse reaction—removing H2A.Z-H2B dimers via a unique translocation mechanism at the H2A-H2B interface. H2A.Z incorporation at the +1 nucleosome reduces the transcriptional barrier to RNA polymerase II, promotes DNA unwrapping and chromatin accessibility, and enables formation of more regular condensed chromatin fiber arrays; its function is context-dependent, tuned by post-translational modifications including acetylation (by TIP60/KAT5 at K7 and K4/7/11/13/15, and by KAT2A/GCN5 at H2A.Z.1 specifically, which recruits BRD2 to promote RNAPII), monomethylation (by SETD6 at K7, associated with differentiation), dimethylation (by SMYD3 at K101, stabilizing H2A.Z and preventing ANP32E-mediated removal), monoubiquitylation (by RING1b/PRC1 at K3, maintaining Polycomb repression and antagonizing BRD2), deSUMOylation (by SENP5, promoting HR repair), and molecular crosstalk with DNA methylation (mutually antagonistic distributions genome-wide). H2A.Z also scaffolds SUV420H1-mediated H4K20me2 deposition at replication origins to license and activate early DNA replication, and participates in chromosome segregation, meiotic DSB formation, alternative pre-mRNA splicing of weak introns, suppression of antisense transcripts (redundantly with RNAi and heterochromatin factors), memory consolidation in the hippocampus and cortex, and neural crest cell differentiation via the PWWP2A interaction network.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"H2A.Z (H2AZ1/H2AFZ) is a conserved histone H2A variant deposited into nucleosomes flanking promoters and regulatory elements, where it tunes the chromatin template for transcription, replication, and genome stability [#0, #3, #2]. Its incorporation is catalyzed by the ATP-dependent SWR1/SRCAP-family remodeler, in which the Swr1/Domino ATPase drives histone exchange and the Swc2/YL1 (VPS72) subunit provides H2A.Z-specific recognition through a whip-like domain that engages the variant's hyperacidic patch and extended αC helix [#0, #1, #13, #14]; single-molecule analysis resolves deposition into discrete priming, H2A loss, and dimer-release steps assisted by chaperones such as Chz1 and Nap1 [#33, #34, #35, #36]. The reverse reaction is performed by INO80, which translocates uniquely at the H2A-H2B interface to evict H2A.Z-H2B dimers, working with the chaperone ANP32E [#17, #12]. Structurally, H2A.Z's shorter C-terminus increases mobility of nucleosomal DNA termini and unwrapping while enabling more regular, condensed chromatin fibers, providing a basis for its context-dependent activating and repressive roles [#31, #30, #22]. At the +1 nucleosome H2A.Z lowers the barrier to elongating RNA Pol II [#22], and it cooperates with Polycomb—being monoubiquitylated by RING1b to maintain repression of bivalent genes while antagonizing the bromodomain reader BRD2 [#5, #16]—and is mutually antagonistic with DNA methylation genome-wide [#6]. H2A.Z function is further tuned by post-translational modifications: acetylation by TIP60/KAT5 (notably at K7) and by KAT2A/GCN5 on H2A.Z.1 (recruiting BRD2 to promote RNAPII), monomethylation by SETD6 at K7, and dimethylation by SMYD3 at K101 that stabilizes the variant against ANP32E removal [#28, #27, #10, #15]. Beyond transcription, H2A.Z scaffolds SUV420H1-mediated H4K20me2 to license early replication origins [#20, #21], supports chromosome segregation and centromere integrity, ES cell differentiation and lineage commitment, memory consolidation, and is required for proper nuclear reassembly after mitosis [#37, #4, #19, #41]. Somatic and germline mutations in SRCAP-complex subunits cause defective H2A.Z deposition that drives epigenetic instability in uterine leiomyoma [#49].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Established that H2A.Z functions in transcriptional regulation through a chromatin pathway distinct from canonical remodeling/coactivator complexes, raising the question of how it is targeted to genes.\",\n      \"evidence\": \"Genetic epistasis and locus-specific ChIP at PHO5/GAL1 in S. cerevisiae\",\n      \"pmids\": [\"11081628\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the deposition machinery\", \"Mechanism of locus-specific targeting unresolved\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Identified the enzymatic basis of H2A.Z deposition, answering how the variant is placed into nucleosomes.\",\n      \"evidence\": \"Biochemical reconstitution of ATP-dependent H2A-for-H2A.Z exchange by the SWR1 complex plus in vivo ChIP in yeast\",\n      \"pmids\": [\"14645854\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which subunit confers H2A.Z specificity not yet defined\", \"Step-by-step exchange mechanism unknown\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Dissected SWR1 subunit roles and pinpointed H2A.Z C-terminal recognition, defining how the complex distinguishes the variant.\",\n      \"evidence\": \"Subunit pulldowns, in vitro exchange assays, and H2A.Z C-terminal mutagenesis\",\n      \"pmids\": [\"16299513\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic basis of Swc2-H2A.Z recognition not resolved\", \"Chaperone contributions unclear\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Mapped the genomic architecture of H2A.Z nucleosomes, establishing its hallmark positioning flanking nucleosome-free regions at promoters.\",\n      \"evidence\": \"Deep sequencing of ~322,000 H2A.Z nucleosomes genome-wide in yeast\",\n      \"pmids\": [\"17392789\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of positioning at inactive genes unclear\", \"No causal link to specific transcriptional outcomes\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Revealed that H2A.Z carries distinguishing PTMs, with RING1b-mediated monoubiquitylation marking facultative heterochromatin.\",\n      \"evidence\": \"Fractionation, co-IP, immunofluorescence on the inactive X in mammalian cells\",\n      \"pmids\": [\"17636032\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of ubiquitylation not yet tested\", \"Site of modification not defined here\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Connected H2A.Z to developmental gene regulation and Polycomb, and to mutual antagonism with DNA methylation, defining its epigenetic context.\",\n      \"evidence\": \"ChIP-seq/RNAi in mouse ES cells and reciprocal met1/pie1 mutant genomics in Arabidopsis\",\n      \"pmids\": [\"18992931\", \"18815594\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of H2A.Z-PcG interdependence unresolved\", \"How methylation and H2A.Z exclude each other mechanistically unclear\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Extended H2A.Z function to inducible mammalian enhancers/promoters, centromere silencing, antisense suppression, and identified acetylation sites that modulate nucleosome stability.\",\n      \"evidence\": \"ChIP-seq/RNAi at ERα targets (human), genetic epistasis at centromeres and antisense loci (S. pombe), and acetyl-site mass spec/NCP reconstitution\",\n      \"pmids\": [\"19515975\", \"19910462\", \"19693008\", \"19385636\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How acetylation state is read out in vivo unclear\", \"Centromere role mechanism beyond CENP-C expression not defined\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified specific writers placing methyl and acetyl marks on H2A.Z, linking modifications to differentiation and active transcription.\",\n      \"evidence\": \"In vitro enzymatic assays, mass spec, and ChIP for SETD6 (K7me1) and KAT2A/GCN5 (H2A.Z.1 acetylation recruiting BRD2)\",\n      \"pmids\": [\"23324626\", \"31527837\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Reader proteins for K7me1 not identified\", \"Interplay among competing PTMs at a single residue unclear\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Provided direct mechanistic evidence that H2A.Z lowers the Pol II elongation barrier and demonstrated an in vivo behavioral role in memory.\",\n      \"evidence\": \"Genome-wide NET-seq with H2A.Z depletion (yeast) and fear-conditioning ChIP/expression (mouse)\",\n      \"pmids\": [\"24606920\", \"25219850\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How H2A.Z structurally lowers the barrier not resolved here\", \"Memory effect mechanism at gene-level undefined\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Placed INO80/ANP32E as the H2A.Z removal pathway promoting homologous recombination, and identified BRD2 as an isoform-linked reader.\",\n      \"evidence\": \"Epistasis co-depletion with HR reporter assays and co-IP/ChIP-seq in human cells\",\n      \"pmids\": [\"26142279\", \"26051178\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanistic basis of INO80 dimer eviction not yet structural\", \"Isoform-specific BRD2 effects (H2A.Z.2 vs Z.1) need reconciling\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Solved the structural basis of YL1/Swc2-mediated H2A.Z recognition and defined how methylation (SMYD3 K101me2) and ubiquitylation balance deposition versus removal and Polycomb repression.\",\n      \"evidence\": \"Crystal structures of YL1-H2A.Z-H2B (Drosophila and human), plus SMYD3 enzymatic/co-IP and H2A.Z.1 K3R3 mutagenesis with BRD2 rescue\",\n      \"pmids\": [\"26974124\", \"26974126\", \"27569210\", \"26804911\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How modifications are dynamically coordinated in cells unclear\", \"Structural state during full SWR1 catalytic cycle still incomplete\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Defined the INO80 eviction mechanism, identified the H2A.Z reader PWWP2A, and extended function to cotranscriptional splicing and redundant deposition chaperones.\",\n      \"evidence\": \"Single-molecule/biochemical INO80 translocation assays, H2A.Z interactome with domain mapping, S. pombe splicing genetics, and Nap1/Chz1 double-deletion analysis\",\n      \"pmids\": [\"28604691\", \"28645917\", \"28446597\", \"28883625\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How PWWP2A network directs downstream functions unclear\", \"Splicing role mechanism beyond Prp16 pathway undefined\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Expanded H2A.Z roles to Notch enhancer control, meiotic DSB formation, and gliogenesis via H3K56ac, showing functions across signaling, meiosis, and differentiation.\",\n      \"evidence\": \"ChIP/co-IP/knockdown at RBP-J enhancers, meiotic DSB and nuclear architecture assays (S. pombe), and ASF1a co-IP/ChIP in neural precursors\",\n      \"pmids\": [\"29986055\", \"29145618\", \"29982651\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs indirect contributions to each pathway unclear\", \"Single-lab findings without orthogonal confirmation\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Established H2A.Z as a scaffold for replication-origin licensing and dissected chaperone bioavailability and tissue-specific deposition control.\",\n      \"evidence\": \"In vitro binding/ChIP-seq/nascent-strand sequencing for SUV420H1-H4K20me2-ORC1, Chz1 crystal structure, and Znhit1-YL1 phosphorylation in intestinal stem cells\",\n      \"pmids\": [\"31875854\", \"31107867\", \"30842416\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How H2A.Z is restricted to early origins unclear\", \"Coupling of deposition to replication timing not fully resolved\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Linked H2A.Z structure to function—nucleosome unwrapping, CTCF regulation, isoform-specific compaction, and post-mitotic nuclear reassembly—while showing it is dispensable for transcription in non-dividing cells.\",\n      \"evidence\": \"MNase-X-ChIP-seq/CTCF CUT&RUN, cryo-EM of H2A.Z.2.2 nucleosome, cell-free nuclear reassembly, and in vivo muscle conditional knockout\",\n      \"pmids\": [\"32392318\", \"33073403\", \"32708675\", \"32266374\", \"32109204\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Why H2A.Z is dispensable post-mitotically mechanistically unclear\", \"Relationship between unwrapping and CTCF eviction incompletely defined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Provided structural and disease-level synthesis: cryo-EM of H2A.Z nucleosomes/fibers explaining dual roles, isoform division of labor in cell division, and SRCAP-mutation-driven H2A.Z loss in uterine leiomyoma.\",\n      \"evidence\": \"Cryo-EM with C-terminal mutagenesis, isoform-specific siRNA/imaging, Drosophila ZGA knockdown with HiC, and multi-omic primary-tumor sequencing\",\n      \"pmids\": [\"34643712\", \"34423893\", \"34853314\", \"34349258\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How fiber condensation reconciles with promoter activation unclear\", \"Causal chain from SRCAP mutation to tumorigenesis incomplete\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Resolved the temporal mechanism of SWR1 deposition and defined TIP60-dependent K7 acetylation, nutrient-responsive deacetylation, and acetylation-dependent epigenetic competence.\",\n      \"evidence\": \"Three-color single-molecule FRET and ensemble assays (yeast SWR1C), TIP60 knockout/ChIP, TORC1-Rpd3L-Ino80 deacetylation genetics, and Tip60-dependent bivalent gene activation\",\n      \"pmids\": [\"35263135\", \"36396651\", \"35853868\", \"36888706\", \"36417913\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How discrete ATP steps couple to chaperone handoff in cells unclear\", \"Whether deacetylation directly gates deposition in mammals unconfirmed\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined SUV420H1 structural selectivity for H2A.Z nucleosomes and identified SENP5-mediated deSUMOylation regulating HR repair and radioresistance.\",\n      \"evidence\": \"Cryo-EM of SUV420H1-H2A.Z-nucleosome with mutagenesis, and SUMO-proteomics/co-IP/HR assays with PDO/PDX models\",\n      \"pmids\": [\"37536340\", \"37684630\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"SUMO site(s) on H2A.Z not fully mapped\", \"Therapeutic implications of SENP5 axis untested clinically\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Showed that H2A.Z.1 acetylation status bidirectionally controls memory and couples to neuronal alternative splicing, linking specific PTMs to cognitive output.\",\n      \"evidence\": \"AAV-delivered acetyl-mimic/defective H2A.Z.1 mutants with fear conditioning and RNA/splicing analysis in mouse hippocampus\",\n      \"pmids\": [\"38366138\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Reader machinery translating acetylation into splicing changes unknown\", \"Single-lab in vivo finding without independent replication\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the full repertoire of H2A.Z post-translational modifications, isoform identity, and reader proteins is integrated to specify activating versus repressive outcomes at individual loci remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model linking PTM combinations to context-specific function\", \"Isoform-specific reader/effector logic only partially mapped\", \"In vivo dynamics of deposition-eviction cycling at single loci undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [31, 24, 32, 23]},\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [30, 31]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [22, 3, 7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0000228\", \"supporting_discovery_ids\": [2, 30, 31]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [0, 3, 4]},\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [9, 37, 45]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [0, 1, 31]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [22, 3, 7, 27]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [12, 39]},\n      {\"term_id\": \"R-HSA-69306\", \"supporting_discovery_ids\": [20, 21]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [37, 28]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [4, 29, 46]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [49]}\n    ],\n    \"complexes\": [\"SWR1/SRCAP complex\", \"INO80 complex\", \"TIP60/p400 complex\", \"nucleosome\"],\n    \"partners\": [\"VPS72\", \"ANP32E\", \"SUV420H1\", \"PWWP2A\", \"BRD2\", \"RING1B\", \"SMYD3\", \"KAT5\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}