{"gene":"RBBP4","run_date":"2026-06-10T06:43:36","timeline":{"discoveries":[{"year":1998,"finding":"C. elegans lin-53 encodes a protein similar to RbAp48 and antagonizes Ras signaling in vulval precursor cells; lin-53 and lin-35 (Rb homolog) act in the same synthetic multivulva pathway to repress transcription of genes required for vulval cell fate expression.","method":"Genetic epistasis, loss-of-function mutant analysis, sequence homology","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with defined pathway placement and double-mutant phenotypic readout, replicated across multiple alleles in a classic model organism study","pmids":["9875852"],"is_preprint":false},{"year":1998,"finding":"Drosophila p55 (NURF55, ortholog of RbAp48) is an integral subunit of both the NURF chromatin remodeling complex and the CAF-1 chromatin assembly factor, suggesting it functions as a common platform for chromatin metabolism complexes; immunological studies confirm chromosomal association.","method":"Peptide sequencing, cDNA cloning, immunoprecipitation, immunostaining of polytene chromosomes","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal biochemical identification plus in situ localization, independently replicated in multiple complexes","pmids":["9419341"],"is_preprint":false},{"year":1998,"finding":"Purified recombinant RbAp48 binds 3–4 zinc ions per molecule, with binding activity present in both N- and C-terminal halves, suggesting metal binding is an intrinsic property of the WD-40 propeller structure that may mediate protein-protein interactions.","method":"Metal affinity chromatography, zinc blotting, atomic absorption analysis, metal competition assays","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — in vitro biochemical assay with purified protein, single lab, no functional consequence demonstrated","pmids":["9872415"],"is_preprint":false},{"year":1999,"finding":"In Xenopus oocytes, RPD3 (HDAC) associates with RbAp48 through N- and C-terminal contacts; RbAp48 also interacts with SIN3; RbAp48 selectively binds the N-terminal tail proximal to the histone fold domain of histone H4 in vivo; RPD3 may be targeted to histones through RbAp48 to direct transcriptional repression.","method":"Xenopus oocyte microinjection, cofractionation, co-immunoprecipitation, in vivo binding assays, transcriptional repression assays","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal interactions mapped in vivo with multiple orthogonal methods (fractionation, Co-IP, transcriptional assay), single lab","pmids":["10454532"],"is_preprint":false},{"year":2000,"finding":"RbAp48 belongs to the Rb-associated histone deacetylase complex; HDAC1 mediates formation of an Rb-RbAp48 ternary complex; cell extracts depleted of RbAp48-containing complexes show reduced deacetylase activity associated with Rb; E2F1 and RbAp48 are physically associated in the presence of Rb and HDAC1.","method":"Co-immunoprecipitation from live cells, RbAp48 immunodepletion, histone deacetylase activity assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP plus functional depletion assay, two orthogonal methods in single lab","pmids":["10734134"],"is_preprint":false},{"year":2000,"finding":"RbAp48 interacts with a CBP–phospho-CREB complex: CBP from HeLa nuclear extracts co-immunoprecipitates with RbAp48/RbAp46; RbAp48 lowers the Km of CBP histone acetyltransferase activity; RbAp48 facilitates p300-mediated in vitro transcription of a chromatinized template in an acetylCoA-dependent manner; association of core histones and mononucleosomes with the complex is acetylation-dependent.","method":"Yeast two-hybrid, Co-IP, GST pulldown, in vitro histone acetyltransferase assay (Km measurement), in vitro transcription on chromatinized template","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro enzymatic assay with Km measurement plus reconstituted transcription assay, corroborated by Co-IP, single lab with multiple orthogonal methods","pmids":["10866654"],"is_preprint":false},{"year":2001,"finding":"HDAC3 physically interacts with RbAp48 both in vitro and in live cells, and recruits RbAp48 to Rb; this interaction is independent of effects on Rb-E2F1 binding; RbAp48 is required for transcriptional repression of E2F activity.","method":"Co-immunoprecipitation in vivo and in vitro, transcriptional repression assays","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 2 / Moderate — in vitro and in vivo Co-IP plus functional repression assay, building on prior work with same complex","pmids":["11470869"],"is_preprint":false},{"year":2002,"finding":"Immunoaffinity proteomics of RbAp48 from Jurkat cells identified all known NuRD/Mi-2 complex proteins (including human p66) as interaction partners, plus RNA-binding/pre-mRNA splicing proteins and other novel interactors, suggesting a broader cellular role than previously documented.","method":"Immunoaffinity purification, capillary HPLC-ion-trap mass spectrometry","journal":"Journal of proteome research","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — MS-based interactome from single lab, no functional follow-up for novel interactors","pmids":["12645902"],"is_preprint":false},{"year":2004,"finding":"Drosophila p55 (RbAp48 ortholog) is essential for repression of dE2F2/RBF-regulated target genes in a cell cycle-independent manner; RNAi depletion of p55 derepresses E2F targets regulated by dE2F2/RBF1 and dE2F2/RBF2, but not cell proliferation-coupled E2F targets, indicating distinct repression mechanisms at these two target classes.","method":"RNAi depletion in Drosophila cells, quantitative RT-PCR of E2F target genes, epistasis analysis","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — RNAi loss-of-function with specific transcriptional readout across multiple target genes, epistatic dissection of two E2F repression pathways","pmids":["15456884"],"is_preprint":false},{"year":2006,"finding":"RbAp48 overexpression induces p53-mediated apoptosis in exocrine gland cells under estrogen deficiency conditions; apoptosis requires p53 phosphorylation and E2F-1; siRNA knockdown of RbAp48 inhibits this apoptosis; transgenic RbAp48 expression induces apoptosis specifically in exocrine glands.","method":"Transgenic mouse overexpression, siRNA knockdown, Western blot for p53 phosphorylation, OVX mouse model, genetic knockout (p53−/−, E2F-1−/−, ERα−/−)","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple genetic knockouts used for epistasis, transgenic overexpression and RNAi in vivo, specific apoptotic readout","pmids":["16581768"],"is_preprint":false},{"year":2007,"finding":"RbAp48 overexpression induces cytoskeletal reorganization (loss of actin stress fibers, formation of membranous F-actin rings, cell rounding) in breast cancer cells by increasing K-Ras-GTP levels and activating MAPK; pharmacological MAPK inhibition reverses the cytoskeletal changes; RbAp48 knockdown reduces K-Ras activity.","method":"Transfection/overexpression, siRNA knockdown, Ras activity pulldown (GTP-Ras), pharmacological MAPK inhibition, phalloidin F-actin staining","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — multiple complementary methods (overexpression, knockdown, pharmacological) in single lab, no in vitro reconstitution","pmids":["17974974"],"is_preprint":false},{"year":2010,"finding":"Crystal structure (1.9 Å) of RbAp48 bound to the 15 N-terminal amino acids of FOG-1 reveals that the FOG-1 peptide contacts a negatively charged pocket on top of the RbAp48 β-propeller, distinct from the histone H4-binding surface; RbAp48 interacts with NuRD subunit MTA-1 via a surface distinct from the FOG-binding pocket, establishing how NuRD assembly facilitates cofactor interactions.","method":"X-ray crystallography (1.9 Å), biochemical binding assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure with two distinct binding surfaces defined at high resolution, single lab with structural and biochemical orthogonal validation","pmids":["21047798"],"is_preprint":false},{"year":2012,"finding":"The H3-H4 histone complex shows structural plasticity that facilitates allosteric exchange between RbAp48 and the histone chaperone ASF1; this exchange has a central role in new nucleosome assembly.","method":"Biochemical binding/exchange assays, mass spectrometry, EPR (ESR), structural analysis","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — reconstitution of chaperone exchange in vitro with multiple biophysical methods (MS, EPR), single lab","pmids":["23178455"],"is_preprint":false},{"year":2013,"finding":"RbAp48 modifies histone acetylation in the dentate gyrus (DG); dominant-negative inhibition of RbAp48 in young mouse forebrain causes hippocampus-dependent memory deficits and regionally selective decrease in histone acetylation in the DG; RbAp48 up-regulation in aged DG rescues age-related memory loss and histone acetylation abnormalities.","method":"Transgenic dominant-negative mouse, viral vector overexpression in aged mice, fMRI, novel object recognition, Morris water maze, histone acetylation measurement","journal":"Science translational medicine","confidence":"High","confidence_rationale":"Tier 2 / Moderate — bidirectional (loss- and gain-of-function) in vivo experiments with matched behavioral and molecular readouts, single lab with multiple orthogonal approaches","pmids":["23986399"],"is_preprint":false},{"year":2014,"finding":"Crystal structure of RbAp48 in complex with MTA1 shows that RbAp48 binds MTA1 using the same site used to bind histone H4, demonstrating that assembly into NuRD modulates RbAp46/48 interactions with histones; MTA proteins act as scaffolds for NuRD complex assembly; the RbAp48-MTA1 interaction is essential for in vivo integration of RbAp46/48 into NuRD.","method":"X-ray crystallography, mutagenesis, co-immunoprecipitation to test in vivo integration","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure plus mutagenesis plus in vivo Co-IP validation, multiple orthogonal methods in single lab","pmids":["24920672"],"is_preprint":false},{"year":2015,"finding":"Crystal structure of RBBP4 bound to PHF6 peptide (residues 162-170) reveals that PHF6 contacts the top surface of the RBBP4 β-propeller via a positively charged pair of residues inserting into a negatively charged pocket; this pocket overlaps with FOG1 and histone H3 binding but is distinct from histone H4, Su(z)12, and MTA1 sites; PHF6 mutants impairing this interaction reduce PHF6-mediated transcriptional repression in vivo and RBBP4 knockdown diminishes PHF6-mediated repression.","method":"X-ray crystallography, mutagenesis, Co-IP, transcriptional reporter assay, siRNA knockdown","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure plus mutagenesis (in vitro and in vivo) plus functional repression assay, multiple orthogonal methods","pmids":["25601084"],"is_preprint":false},{"year":2015,"finding":"RBBP4 depletion in mouse oocytes causes hyperacetylation of histones H3K4, H4K8, H4K12, H4K16 during meiosis I, leading to multipolar spindles at metaphase I, chromosome misalignment, and aneuploidy at metaphase II; RBBP4-mediated histone deacetylation promotes bipolar spindle assembly at least partially through Aurora kinase C (AURKC) function.","method":"siRNA depletion in mouse oocytes, immunofluorescence for spindle assembly, histone acetylation Western blot, chromosome spread analysis","journal":"Biology of reproduction","confidence":"High","confidence_rationale":"Tier 2 / Moderate — clean loss-of-function with specific molecular (histone acetylation) and cellular (spindle/aneuploidy) readouts, epistasis with AURKC","pmids":["25788661"],"is_preprint":false},{"year":2015,"finding":"RbAp48 is essential for vertebrate cell viability; conditional knockout in chicken DT40 cells causes delayed S phase, slow DNA synthesis, impaired nascent nucleosome formation, G2/M accumulation, aberrant mitosis with highly condensed chromosomes and chromosome missegregation, dissociation of HP1 from pericentromeric heterochromatin, and elevated H3K9 acetylation with reduced H3K9 methylation.","method":"Tetracycline-inducible conditional knockout, cell cycle analysis by flow cytometry, BrdU incorporation, chromosome spread, immunostaining for HP1 and histone modifications","journal":"Chromosome research","confidence":"High","confidence_rationale":"Tier 2 / Moderate — conditional knockout with multiple orthogonal readouts (cell cycle, DNA synthesis, chromosome structure, epigenetic marks)","pmids":["26667624"],"is_preprint":false},{"year":2016,"finding":"In C. elegans, LIN-53 (RbAp46/48 ortholog) is required for CENP-A(HCP-3) localization to holocentromeres; LIN-53 and CENP-A localizations are interdependent; LIN-53 localizes to the centromere during metaphase in a CENP-A- and M18BP1(KNL-2)-dependent manner; LIN-53 depletion causes anaphase bridges and chromosome missegregation; this centromeric function is independent of histone acetylation, H3K27 trimethylation, or known chromatin-modifying complexes.","method":"RNAi depletion, immunofluorescence, genetic epistasis with CENP-A and M18BP1 mutants","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — loss-of-function with multiple epistatic partners defined, specific centromeric localization phenotype, independent pathway placement","pmids":["26904949"],"is_preprint":false},{"year":2016,"finding":"MTA1 can recruit two copies of RBBP4 simultaneously; negative stain electron microscopy and chemical crosslinking define a low-resolution model of an MTA1-(RBBP4)2 subcomplex.","method":"Biochemical binding assays, negative stain electron microscopy, chemical crosslinking/mass spectrometry","journal":"Protein science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — structural EM plus crosslinking/MS, single lab, low-resolution model","pmids":["27144666"],"is_preprint":false},{"year":2016,"finding":"RbAp48 binds to the HIV-1 LTR in vitro and represses HIV-1 LTR-mediated basal and activated transcription; ChIP analysis shows RbAp48 occupancy at the HIV-1 LTR in cells; knockdown of RbAp48 promotes HIV infection and virus particle production.","method":"EMSA, ChIP, siRNA knockdown, HIV-1 LTR-luciferase reporter assay","journal":"International journal of molecular medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — EMSA and ChIP plus functional knockdown, single lab","pmids":["27222146"],"is_preprint":false},{"year":2017,"finding":"Crystal structure of RBBP4 in complex with BCL11A N-terminal peptide (residues 2-16) shows BCL11A contacts the side of the RBBP4 β-propeller via novel interactions distinct from histone H3; BCL11A competes with histone H3 for binding to the negatively charged top face of RBBP4; BCL11A(2-16) pulls down RBBP4, RBBP7, and components of PRC2, NuRD, and SIN3A from cell lysates.","method":"X-ray crystallography, fluorescence polarization competition assay, GST pulldown from cell lysate","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure with competition assay and pulldown validation, multiple orthogonal methods in single lab","pmids":["29263092"],"is_preprint":false},{"year":2018,"finding":"Crystal structure of RBBP4 bound to the N-terminal 14 amino acids of ZNF827 shows RBBP4 forms a negatively charged channel binding ZNF827 through electrostatic interactions; specific RBBP4 residues required for this interaction were identified and mutation prevents RBBP4 binding to both ZNF827 and telomeres, establishing how NuRD is recruited to ALT telomeres via ZNF827.","method":"X-ray crystallography, mutagenesis, ChIP, Co-IP","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure plus structure-guided mutagenesis validated by ChIP, multiple orthogonal methods","pmids":["30045876"],"is_preprint":false},{"year":2018,"finding":"RbAp48 controls expression of BDNF and GPR158 (components of osteocalcin signaling) in mouse hippocampus; inhibition of RbAp48 in hippocampal formation blocks OCN's beneficial effects on cognition and causes discrimination memory deficits; disruption of OCN/GPR158 signaling downregulates RbAp48, creating a feedback loop; activation of OCN/GPR158 increases RbAp48 expression in aged DG and rescues age-related memory loss.","method":"Viral vector RbAp48 inhibition in vivo, GPR158 pharmacological blockade, gene expression analysis, behavioral memory tests","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — bidirectional in vivo manipulation with molecular and behavioral readouts, single lab","pmids":["30355501"],"is_preprint":false},{"year":2019,"finding":"LIN-53 (RBBP4/7 ortholog) interacts with the NuRD complex in C. elegans muscles to maintain muscle integrity; LIN-53 also interacts with the SIN3 HDAC complex required for normal lifespan; lin-53 and sin-3 mutants show decreased trehalose levels; trehalose supplementation or enhancement via insulin/IGF1 signaling rescues lifespan defects.","method":"Genetic mutant analysis, transcriptomics, metabolomics, epistasis with trehalose feeding and insulin pathway","journal":"Aging cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic and metabolomic epistasis with rescue experiments, single lab","pmids":["31397537"],"is_preprint":false},{"year":2020,"finding":"RBBP4 loss in mouse embryos causes hyperacetylated histones and severe apoptosis in blastocysts; trophoblast lineage is properly specified but epiblast and primitive endoderm are compromised; RBBP4 is essential for early mouse embryogenesis and inner cell mass formation.","method":"Conditional knockout mouse, blastocyst outgrowth assay, immunofluorescence for lineage markers and histone acetylation, TUNEL apoptosis assay","journal":"Biology of reproduction","confidence":"High","confidence_rationale":"Tier 2 / Moderate — in vivo knockout with lineage specification analysis and histone modification readout, multiple orthogonal methods","pmids":["32285100"],"is_preprint":false},{"year":2020,"finding":"Structure-based design of bicyclic peptide inhibitors targeting the RbAp48/MTA1 protein-protein interaction interface achieves nanomolar affinity (KD = 8.56 nM); crystallographic analysis guided affinity optimization via hydrophobic aromatic linker interactions with a hydrophobic residue on RbAp48.","method":"X-ray crystallography, fluorescence polarization/binding affinity measurement, protease stability assay","journal":"Angewandte Chemie (International ed. in English)","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure-guided design with quantitative binding measurement and stability assay","pmids":["33022847"],"is_preprint":false},{"year":2021,"finding":"Double knockdown of Rbbp4 and Rbbp7 (but not individually) causes embryonic lethality at morula-to-blastocyst transition with cell cycle block, disrupted lineage specification, and a dramatic increase in histone H3.3 and H3K27ac; ChIP-seq shows RBBP4/7 target gene promoters are enriched for H3.3; RBBP4/7 regulate H3.3 deposition epigenetically.","method":"siRNA double knockdown in mouse embryos, ChIP-seq for H3.3, RNA-seq, immunofluorescence","journal":"Epigenetics","confidence":"High","confidence_rationale":"Tier 2 / Moderate — genome-wide ChIP-seq plus RNA-seq plus phenotypic analysis, single lab with multiple orthogonal methods","pmids":["34709113"],"is_preprint":false},{"year":2021,"finding":"RBBP4 deficiency in mouse ESCs causes spontaneous differentiation into mesendodermal lineages; RBBP4 is essential for PRC2 genomic targeting to a subset of developmental genes; RBBP4 sustains Oct4 and Sox2 expression; forced co-expression of Oct4 and Sox2 fully rescues pluripotency in Rbbp4-null ESCs.","method":"Knockout ESCs, RNA-seq, ChIP-seq for PRC2 components, rescue by Oct4/Sox2 overexpression","journal":"Stem cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — knockout plus genome-wide ChIP-seq plus epistatic rescue, multiple orthogonal approaches","pmids":["33606987"],"is_preprint":false},{"year":2021,"finding":"In Tetrahymena, the RBBP4/7 ortholog RebL1 physically interacts with histone H4 and co-purifies with subunits of CAF1, Hat1, Rpd3, and MuvB complexes; RebL1 is a component of a MuvB-like complex containing Lin54, Lin9, and RebL1; RebL1 and Lin54 bind genic and intergenic regions genome-wide; RebL1 depletion suppresses Rad51 expression, consistent with DNA repair roles.","method":"Affinity purification/mass spectrometry, ChIP-seq, RNAi depletion, Western blot","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — AP-MS plus ChIP-seq plus functional depletion, single lab","pmids":["34086947"],"is_preprint":false},{"year":2022,"finding":"RBBP4 forms a complex with p300 histone acetyltransferase in the nucleus of GBM cells (demonstrated by proximity ligation assay); ChIP-seq shows co-occupancy of RBBP4/p300 at promoters/enhancers with H3K27ac; RBBP4 and p300 co-regulate 1,485 genes including C-MYC; RBBP4 or p300 knockdown sensitizes GBM cells to temozolomide.","method":"Proximity ligation assay, ChIP-seq, shRNA knockdown, RNA-seq, in vivo orthotopic tumor model","journal":"Neuro-oncology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — PLA for complex formation plus ChIP-seq co-occupancy plus in vivo functional validation, multiple orthogonal methods","pmids":["35231103"],"is_preprint":false},{"year":2022,"finding":"RBBP4 loss in zebrafish disrupts neural progenitor cell cycle progression independent of Rb1 (rbbp4; rb1 double mutants show additive M-phase accumulation); Rbbp4 loss leads to Tp53 acetylation and Tp53-dependent apoptosis in developing brain; Tp53 knockdown/knockout suppresses apoptosis in rbbp4 mutants.","method":"Zebrafish genetic mutant analysis (rbbp4, rb1, tp53 mutants), immunofluorescence for γ-H2AX and M-phase markers, epistasis with tp53 morpholino/knockout","journal":"Developmental dynamics","confidence":"High","confidence_rationale":"Tier 2 / Moderate — genetic epistasis with double mutants, specific molecular readout (Tp53 acetylation), rescue experiments","pmids":["35266256"],"is_preprint":false},{"year":2022,"finding":"Photoaffinity labeling identified RBBP4 as a direct cellular target of protopanaxadiol (PPD) in HCT116 colorectal cancer cells; PPD binding to RBBP4 decreases RBBP4-dependent H3K27me3; PPD inhibition of cell proliferation/migration is antagonized by RBBP4 silencing, confirming RBBP4 as a functional target.","method":"Photoaffinity labeling chemoproteomic pulldown, H3K27me3 Western blot, siRNA knockdown rescue","journal":"Chembiochem","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — cell-permeable probe pulldown with functional rescue, single lab","pmids":["35442561"],"is_preprint":false},{"year":2023,"finding":"RBBP4 recruits transcription factors and epigenetic regulators to the promoters of MRN complex genes (Mre11, Rad50, NBS1) to regulate their expression and thereby controls DNA double-strand break repair; RBBP4 disruption increases DNA damage sensitivity to TMZ and radiotherapy in GBM cells.","method":"ChIP-seq, shRNA knockdown, γ-H2AX assay, cell proliferation assays","journal":"Cancer letters","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — ChIP plus functional knockdown, single lab","pmids":["36736531"],"is_preprint":false},{"year":2023,"finding":"RBBP4 functions as an epigenetic barrier to totipotency: it binds endogenous retroviruses (ERVs) and recruits G9a to deposit H3K9me2 on ERVL elements and recruits KAP1 to deposit H3K9me3 on ERV1/ERVK elements; RBBP4 also facilitates nucleosome occupancy at ERVK/ERVL sites in heterochromatin via chromatin remodeler CHD4; RBBP4 depletion activates transposable elements and 2C genes, reprogramming ESCs toward totipotency.","method":"Auxin-induced degron depletion, ChIP-seq for H3K9me2/me3 and nucleosome occupancy (ATAC-seq), Co-IP for G9a/KAP1/CHD4, RNA-seq","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 2 / Strong — rapid depletion system with genome-wide ChIP-seq plus Co-IP plus multiple epigenetic marks, mechanistically comprehensive single study","pmids":["37021556"],"is_preprint":false},{"year":2024,"finding":"ZNF512B contains a variant NuRD-interaction motif (NIM) that binds RBBP4; crystal structure of this ZNF512B NIM bound to RBBP4 demonstrates it is necessary and sufficient for high-affinity NuRD binding; ZNF512B recruits NuRD through RBBP4 to repress gene expression.","method":"X-ray crystallography, biochemical binding assays, mutagenesis, transcriptome analysis, reporter assays","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure plus mutagenesis validation plus functional transcriptional assay, multiple orthogonal methods","pmids":["39460621"],"is_preprint":false},{"year":2024,"finding":"RBBP4 knockdown in mouse E12.5 neocortical progenitors reduces neuronal output, specifically affecting CTIP2-expressing deep-layer neurons; RBBP4 genome-wide occupancy is primarily at distal regulatory elements; RBBP4 binds the Cdon gene (Shh pathway receptor); Cdon knockdown phenocopies RBBP4 knockdown; CDON overexpression rescues neurogenesis defects caused by RBBP4 loss.","method":"CRISPR/Cas9 knockdown in embryonic neocortex, ChIP-seq, immunofluorescence for neuronal markers, rescue by CDON overexpression","journal":"eNeuro","confidence":"High","confidence_rationale":"Tier 2 / Moderate — ChIP-seq plus phenotypic rescue experiment plus loss-of-function, multiple orthogonal methods identifying target gene","pmids":["39592227"],"is_preprint":false},{"year":2025,"finding":"In chronic stress/isoflurane anesthesia cognitive impairment, RbAp48 interacts with HDAC2 (demonstrated by Co-IP); chronic stress reduces RbAp48 expression and increases HDAC2 levels and their interaction, decreasing H3K9ac and H4K12ac; RbAp48 overexpression restores histone acetylation, increases BDNF, and rescues memory deficits.","method":"Co-immunoprecipitation, Western blot, adenoviral RbAp48 overexpression in vivo and in vitro, fear conditioning behavioral test","journal":"Journal of anesthesia and translational medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — Co-IP plus rescue experiment, single lab, no independent replication","pmids":["41930277"],"is_preprint":false},{"year":2025,"finding":"RBBP4 knockout in TMZ-resistant glioblastoma cells (identified by CRISPR functional genomic screen using epigenetic knockout library) significantly impairs cell proliferation without affecting MGMT expression; RBBP4 loss downregulates G2/M checkpoint cell cycle genes and causes increased cell size and multinucleation indicative of disrupted mitotic progression.","method":"CRISPR/Cas9 dropout screen, RNA-seq after RBBP4 KO, live-cell imaging, immunofluorescence","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — unbiased functional genomic screen plus transcriptomics plus cell imaging, preprint not peer-reviewed","pmids":[],"is_preprint":true}],"current_model":"RBBP4 (RbAp48) is a WD-40 repeat histone chaperone that serves as a scaffold subunit of multiple chromatin-modifying complexes (NuRD, PRC2, CAF-1, NURF, SIN3A, CoREST), binding histone H4 via its β-propeller top face and recruiting HDACs (HDAC1/2/3) and histone acetyltransferases (CBP/p300) to regulate transcription; structural studies have defined distinct binding surfaces on the β-propeller for histone H4, histone H3, MTA1/NuRD assembly, and transcriptional cofactors (FOG-1, PHF6, BCL11A, ZNF827, ZNF512B), with MTA1 binding occluding the histone H4 site; functionally, RBBP4 is required for heterochromatin maintenance (H3K9me2/3 deposition via G9a/KAP1 at ERV loci), centromere assembly, cell cycle progression (especially G2/M), histone deacetylation during meiosis, nucleosome assembly via histone H3-H4 chaperone exchange with ASF1, PRC2 genomic targeting in stem cells, and neural progenitor differentiation."},"narrative":{"mechanistic_narrative":"RBBP4 (RbAp48) is a WD-40 β-propeller histone chaperone that functions as a shared scaffold subunit of multiple chromatin-modifying complexes, coupling histone binding to transcriptional repression and chromatin assembly [PMID:9419341, PMID:10454532]. It selectively binds the N-terminal tail of histone H4 in vivo and serves as a common platform for the NURF remodeling and CAF-1 assembly complexes [PMID:9419341, PMID:10454532], and biophysical reconstitution shows it participates in allosteric H3-H4 exchange with the chaperone ASF1 during new nucleosome assembly [PMID:23178455]. RBBP4 targets histone deacetylase activity to chromatin: it associates with RPD3/HDAC1, HDAC3, and SIN3 to direct deacetylation and transcriptional repression, including repression downstream of Rb/E2F [PMID:10454532, PMID:10734134, PMID:11470869], and it interacts with HDAC2 and with the CBP/p300 acetyltransferases—lowering the Km of CBP and facilitating p300-dependent transcription on chromatinized templates—positioning it at both ends of the histone acetylation cycle [PMID:10866654, PMID:35231103, PMID:41930277]. A series of crystal structures define how distinct surfaces of the β-propeller engage histones versus cofactors: the top face binds a negatively charged pocket used by FOG-1, histone H3, and PHF6, the side surface is contacted by BCL11A and ZNF827, and the histone H4 site is occluded when MTA1 binds, with MTA1 acting as the scaffold that integrates RBBP4 into NuRD and can recruit two RBBP4 copies [PMID:21047798, PMID:24920672, PMID:25601084, PMID:27144666, PMID:29263092, PMID:30045876, PMID:39460621]. Through these interactions RBBP4 enforces heterochromatin and developmental gene silencing: it recruits G9a and KAP1 to deposit H3K9me2/me3 at endogenous retroviruses and acts as an epigenetic barrier to totipotency [PMID:37021556], directs PRC2 genomic targeting in embryonic stem cells to sustain pluripotency via Oct4/Sox2 [PMID:33606987], and is required for histone deacetylation during oocyte meiosis, embryogenesis, cell cycle progression, and centromere/CENP-A assembly [PMID:25788661, PMID:26667624, PMID:26904949, PMID:32285100]. RBBP4 is essential for vertebrate cell viability and proper mitosis, with loss causing G2/M accumulation, impaired nucleosome formation, chromosome missegregation, and Tp53-dependent apoptosis [PMID:26667624, PMID:35266256]. In the nervous system it controls hippocampal histone acetylation and BDNF/GPR158 signaling required for memory [PMID:23986399, PMID:30355501], and it drives neural progenitor differentiation by binding distal regulatory elements at target genes such as Cdon [PMID:39592227].","teleology":[{"year":1998,"claim":"Established that the RBBP4 ortholog is a transcriptional repressor acting genetically with the Rb pathway and is a physical subunit of distinct chromatin machines, defining it as a shared chromatin platform rather than a single-complex factor.","evidence":"C. elegans genetic epistasis (lin-53/lin-35) and Drosophila p55 biochemical purification from NURF and CAF-1 with polytene chromosome localization","pmids":["9875852","9419341"],"confidence":"High","gaps":["Molecular basis of histone or complex recognition not yet defined","Direct enzymatic partners not yet identified"]},{"year":1999,"claim":"Showed RBBP4 selectively binds the histone H4 N-terminal tail in vivo and bridges HDAC (RPD3) and SIN3 to chromatin, establishing it as the targeting subunit that delivers deacetylase activity for repression.","evidence":"Xenopus oocyte microinjection, cofractionation, Co-IP, and transcriptional repression assays","pmids":["10454532"],"confidence":"High","gaps":["Structural basis of H4 recognition not resolved","Did not distinguish which complexes use this interaction in cells"]},{"year":2000,"claim":"Connected RBBP4 to both histone deacetylation (Rb-HDAC1 ternary complex) and histone acetylation (lowering CBP/p300 Km and enabling chromatin transcription), placing it at both poles of the acetylation cycle.","evidence":"Co-IP plus RbAp48 immunodepletion deacetylase assays, and yeast two-hybrid/GST pulldown with in vitro HAT and chromatin transcription assays","pmids":["10734134","10866654"],"confidence":"High","gaps":["How a single scaffold partitions between HAT and HDAC complexes in vivo unresolved","In vitro Km effects not validated genome-wide"]},{"year":2001,"claim":"Extended the HDAC repertoire to HDAC3 recruited to Rb and showed RBBP4 is functionally required for E2F repression, generalizing its role across deacetylases.","evidence":"In vitro and in vivo Co-IP plus transcriptional repression assays","pmids":["11470869"],"confidence":"High","gaps":["Selectivity between HDAC1/2/3 complexes not defined"]},{"year":2002,"claim":"Defined the RBBP4 interactome as encompassing the complete NuRD/Mi-2 complex plus RNA-processing factors, broadening its documented cellular role.","evidence":"Immunoaffinity purification with capillary HPLC-ion-trap mass spectrometry from Jurkat cells","pmids":["12645902"],"confidence":"Medium","gaps":["Novel splicing-factor interactors never functionally validated","MS interactome from a single cell type"]},{"year":2007,"claim":"Linked RBBP4 dosage to cytoplasmic signaling and apoptosis (K-Ras/MAPK activation, p53-dependent apoptosis), raising non-chromatin or indirect functions.","evidence":"Transgenic overexpression, siRNA, Ras-GTP pulldown, pharmacological MAPK inhibition, and genetic knockout epistasis in mouse models","pmids":["16581768","17974974"],"confidence":"Medium","gaps":["Mechanism connecting a nuclear chaperone to cytoplasmic Ras activity not established","No in vitro reconstitution of the signaling link"]},{"year":2012,"claim":"Resolved how RBBP4 hands off histones, demonstrating allosteric H3-H4 exchange with ASF1 central to new nucleosome assembly.","evidence":"Reconstituted in vitro chaperone exchange assays with mass spectrometry, EPR, and structural analysis","pmids":["23178455"],"confidence":"High","gaps":["Coupling of this exchange to specific assembly complexes (CAF-1) in vivo not shown"]},{"year":2015,"claim":"Defined the structural logic of the β-propeller as a multi-surface hub: the top-face pocket (FOG-1, H3, PHF6) is mutually exclusive with cofactors, while MTA1 binding occludes the histone H4 site to integrate RBBP4 into NuRD.","evidence":"Crystal structures of RBBP4 with FOG-1, MTA1, and PHF6 peptides, with mutagenesis, competition assays, Co-IP, and reporter assays","pmids":["21047798","24920672","25601084"],"confidence":"High","gaps":["How competition is regulated dynamically in cells not addressed","Stoichiometry within intact complexes not fully resolved"]},{"year":2016,"claim":"Established assembly architecture (MTA1 recruiting two RBBP4 copies) and an acetylation-independent centromeric function requiring CENP-A and M18BP1, revealing roles beyond chromatin modification.","evidence":"Negative-stain EM/crosslinking of MTA1-(RBBP4)2, and C. elegans RNAi with CENP-A/M18BP1 epistasis and immunofluorescence","pmids":["27144666","26904949"],"confidence":"High","gaps":["High-resolution NuRD subcomplex structure lacking","Molecular mechanism of centromeric CENP-A loading by RBBP4 unknown"]},{"year":2016,"claim":"Implicated RBBP4 in meiotic genome stability and in viral transcriptional control, broadening its functional reach.","evidence":"siRNA depletion in mouse oocytes with spindle/aneuploidy and histone acetylation readouts and AURKC epistasis; EMSA, ChIP, and LTR reporter assays for HIV-1","pmids":["25788661","27222146"],"confidence":"High","gaps":["Direct deacetylase complex responsible for meiotic deacetylation not pinpointed","HIV LTR repression mechanism is correlative (single lab)"]},{"year":2015,"claim":"Demonstrated that RBBP4 is essential for vertebrate viability with intertwined defects in S-phase, nucleosome assembly, mitosis, and heterochromatin maintenance.","evidence":"Tetracycline-inducible conditional knockout in chicken DT40 cells with cell-cycle, BrdU, chromosome, and HP1/histone-mark analyses","pmids":["26667624"],"confidence":"High","gaps":["Which downstream defect is primary versus secondary not dissected"]},{"year":2018,"claim":"Extended structural recruitment principles to the propeller side surface (BCL11A, ZNF827) and showed ZNF827 directs NuRD to ALT telomeres, generalizing the cofactor-recruitment paradigm.","evidence":"Crystal structures of RBBP4 with BCL11A and ZNF827 peptides with competition assays, structure-guided mutagenesis, ChIP, and Co-IP","pmids":["29263092","30045876"],"confidence":"High","gaps":["In vivo selectivity among competing top-face/side-face ligands not resolved"]},{"year":2018,"claim":"Defined a hippocampal RBBP4 program controlling histone acetylation and BDNF/GPR158 osteocalcin signaling required for memory and reversible in aging.","evidence":"Dominant-negative transgenic and viral overexpression mice with fMRI, behavioral memory tests, and histone acetylation measurements; pharmacological GPR158 blockade","pmids":["23986399","30355501"],"confidence":"High","gaps":["Chromatin complex mediating DG-specific acetylation changes not identified","Direct versus systemic contributions to memory not separated"]},{"year":2020,"claim":"Showed RBBP4 (and redundantly RBBP7) is essential for early embryogenesis, restraining histone acetylation and H3.3 deposition to permit lineage specification.","evidence":"Conditional knockout and siRNA double-knockdown mouse embryos with lineage marker immunofluorescence, TUNEL, ChIP-seq for H3.3, and RNA-seq","pmids":["32285100","34709113"],"confidence":"High","gaps":["Degree of RBBP4/RBBP7 redundancy in somatic tissues not quantified","Mechanism restraining H3.3 deposition not biochemically defined"]},{"year":2021,"claim":"Established RBBP4 as required for PRC2 genomic targeting and pluripotency maintenance in ESCs, with the differentiation phenotype rescued by Oct4/Sox2.","evidence":"Knockout ESCs with RNA-seq, PRC2 ChIP-seq, and epistatic rescue by Oct4/Sox2 overexpression","pmids":["33606987"],"confidence":"High","gaps":["How RBBP4 directs PRC2 to a specific gene subset mechanistically unclear"]},{"year":2023,"claim":"Defined RBBP4 as an epigenetic barrier to totipotency, recruiting G9a and KAP1 to deposit H3K9me2/me3 at ERVs and using CHD4 for nucleosome occupancy in heterochromatin.","evidence":"Auxin-induced degron depletion with ChIP-seq for H3K9me2/me3, ATAC-seq, Co-IP for G9a/KAP1/CHD4, and RNA-seq","pmids":["37021556"],"confidence":"High","gaps":["How RBBP4 selects ERV families for distinct methyltransferases not resolved"]},{"year":2024,"claim":"Refined the cofactor-recruitment model with a variant NuRD-interaction motif in ZNF512B and identified a distal-enhancer-driven neural differentiation program acting through the Shh receptor Cdon.","evidence":"Crystal structure of ZNF512B NIM-RBBP4 with mutagenesis and transcriptome/reporter assays; CRISPR knockdown of RBBP4 in neocortical progenitors with ChIP-seq and CDON rescue","pmids":["39460621","39592227"],"confidence":"High","gaps":["Generality of variant NIMs across other NuRD recruiters untested","How RBBP4 selects deep-layer neuron genes not defined"]},{"year":2022,"claim":"Implicated RBBP4 as a targetable dependency in glioblastoma, co-occupying H3K27ac chromatin with p300 and regulating DNA repair (MRN) and cell cycle genes to influence therapy resistance.","evidence":"Proximity ligation assay, ChIP-seq, shRNA/CRISPR knockdown, RNA-seq, γ-H2AX assays, and orthotopic tumor models","pmids":["35231103","36736531"],"confidence":"Medium","gaps":["Direct versus indirect control of MRN/repair genes not separated","p300 cofactor mechanism is correlative at most loci"]},{"year":null,"claim":"How RBBP4 dynamically partitions among its many mutually exclusive cofactors and complexes to achieve locus- and lineage-specific outcomes, and the structural basis of its acetylation-independent centromeric function, remain unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No quantitative model of complex occupancy in vivo","High-resolution structure of RBBP4 within intact NuRD/PRC2 lacking","Mechanism of CENP-A-dependent centromere loading unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0042393","term_label":"histone binding","supporting_discovery_ids":[3,11,12,14,15]},{"term_id":"GO:0044183","term_label":"protein folding chaperone","supporting_discovery_ids":[12,1]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[11,14,22,35]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[3,8,28,34]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[1,3,30]},{"term_id":"GO:0000228","term_label":"nuclear chromosome","supporting_discovery_ids":[1,17,34]}],"pathway":[{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[1,3,34]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[3,8,28]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[4,17,38]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[25,28,36]}],"complexes":["NuRD","CAF-1","NURF","PRC2"],"partners":["MTA1","HDAC1","CBP/P300","PHF6","BCL11A","ZNF827","ASF1","G9A"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q09028","full_name":"Histone-binding protein RBBP4","aliases":["Chromatin assembly factor 1 subunit C","CAF-1 subunit C","Chromatin assembly factor I p48 subunit","CAF-I 48 kDa subunit","CAF-I p48","Nucleosome-remodeling factor subunit RBAP48","Retinoblastoma-binding protein 4","RBBP-4","Retinoblastoma-binding protein p48"],"length_aa":425,"mass_kda":47.7,"function":"Core histone-binding subunit that may target chromatin assembly factors, chromatin remodeling factors and histone deacetylases to their histone substrates in a manner that is regulated by nucleosomal DNA (PubMed:10866654). Component of the chromatin assembly factor 1 (CAF-1) complex, which is required for chromatin assembly following DNA replication and DNA repair (PubMed:8858152). Component of the core histone deacetylase (HDAC) complex, which promotes histone deacetylation and consequent transcriptional repression (PubMed:9150135). Component of the nucleosome remodeling and histone deacetylase complex (the NuRD complex), which promotes transcriptional repression by histone deacetylation and nucleosome remodeling (PubMed:16428440, PubMed:28977666, PubMed:39460621). Component of the PRC2 complex, which promotes repression of homeotic genes during development (PubMed:29499137, PubMed:31959557). Component of the NURF (nucleosome remodeling factor) complex (PubMed:14609955, PubMed:15310751)","subcellular_location":"Nucleus; Chromosome, telomere","url":"https://www.uniprot.org/uniprotkb/Q09028/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/RBBP4","classification":"Common 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COMPONENT; LIN37","url":"https://www.omim.org/entry/621287"},{"mim_id":"620377","title":"ARMADILLO REPEAT-CONTAINING PROTEIN 12; ARMC12","url":"https://www.omim.org/entry/620377"},{"mim_id":"618514","title":"BRMS1-LIKE TRANSCRIPTIONAL REPRESSOR; BRMS1L","url":"https://www.omim.org/entry/618514"},{"mim_id":"617934","title":"AE-BINDING PROTEIN 2; AEBP2","url":"https://www.omim.org/entry/617934"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoplasm","reliability":"Enhanced"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/RBBP4"},"hgnc":{"alias_symbol":["RbAp48","NURF55","lin-53"],"prev_symbol":[]},"alphafold":{"accession":"Q09028","domains":[{"cath_id":"-","chopping":"43-169","consensus_level":"medium","plddt":87.3624,"start":43,"end":169}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q09028","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q09028-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q09028-F1-predicted_aligned_error_v6.png","plddt_mean":91.69},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=RBBP4","jax_strain_url":"https://www.jax.org/strain/search?query=RBBP4"},"sequence":{"accession":"Q09028","fasta_url":"https://rest.uniprot.org/uniprotkb/Q09028.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q09028/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q09028"}},"corpus_meta":[{"pmid":"9875852","id":"PMC_9875852","title":"lin-35 and lin-53, two 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international","url":"https://pubmed.ncbi.nlm.nih.gov/25165715","citation_count":11,"is_preprint":false},{"pmid":"30045876","id":"PMC_30045876","title":"Structural and functional characterization of the RBBP4-ZNF827 interaction and its role in NuRD recruitment to telomeres.","date":"2018","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/30045876","citation_count":11,"is_preprint":false},{"pmid":"26667624","id":"PMC_26667624","title":"RbAp48 is essential for viability of vertebrate cells and plays a role in chromosome stability.","date":"2015","source":"Chromosome research : an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology","url":"https://pubmed.ncbi.nlm.nih.gov/26667624","citation_count":10,"is_preprint":false},{"pmid":"36691322","id":"PMC_36691322","title":"Circ_0110498 facilitates the cisplatin resistance of non-small cell lung cancer by mediating the miR-1287-5p/RBBP4 axis.","date":"2023","source":"Thoracic cancer","url":"https://pubmed.ncbi.nlm.nih.gov/36691322","citation_count":8,"is_preprint":false},{"pmid":"33506032","id":"PMC_33506032","title":"RBBP4 Enhances Platinum Chemo Resistance in Lung Adenocarcinoma.","date":"2021","source":"BioMed research international","url":"https://pubmed.ncbi.nlm.nih.gov/33506032","citation_count":6,"is_preprint":false},{"pmid":"40187236","id":"PMC_40187236","title":"RBBP4 downregulation increases the sensitivity of A549 and HeLa cells to cisplatin by inhibiting cyclin D1 expression.","date":"2025","source":"Clinics (Sao Paulo, Brazil)","url":"https://pubmed.ncbi.nlm.nih.gov/40187236","citation_count":4,"is_preprint":false},{"pmid":"12430566","id":"PMC_12430566","title":"Cloning and molecular characterization of the Schistosoma mansoni genes RbAp48 and histone H4.","date":"2002","source":"Memorias do Instituto Oswaldo Cruz","url":"https://pubmed.ncbi.nlm.nih.gov/12430566","citation_count":4,"is_preprint":false},{"pmid":"26607076","id":"PMC_26607076","title":"[Effect of RbAp48 knockdown on migration and invasion of human cervical cancer cell line MS751 in vitro].","date":"2015","source":"Nan fang yi ke da xue xue bao = Journal of Southern Medical University","url":"https://pubmed.ncbi.nlm.nih.gov/26607076","citation_count":4,"is_preprint":false},{"pmid":"37664524","id":"PMC_37664524","title":"Expression and clinical significance of RBBP4 gene in lower-grade glioma: An integrative analysis.","date":"2023","source":"Biochemistry and biophysics reports","url":"https://pubmed.ncbi.nlm.nih.gov/37664524","citation_count":3,"is_preprint":false},{"pmid":"26376479","id":"PMC_26376479","title":"RbAp48 Is Critical for the Proliferation of Hypopharyngeal Carcinoma.","date":"2015","source":"ORL; journal for oto-rhino-laryngology and its related specialties","url":"https://pubmed.ncbi.nlm.nih.gov/26376479","citation_count":3,"is_preprint":false},{"pmid":"35622231","id":"PMC_35622231","title":"RBBP4 plays a vital role in the malignant progression of triple-negative breast cancer by regulating epithelial-mesenchymal transition.","date":"2022","source":"Genes & genomics","url":"https://pubmed.ncbi.nlm.nih.gov/35622231","citation_count":3,"is_preprint":false},{"pmid":"39460621","id":"PMC_39460621","title":"ZNF512B binds RBBP4 via a variant NuRD interaction motif and aggregates chromatin in a NuRD complex-independent manner.","date":"2024","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/39460621","citation_count":1,"is_preprint":false},{"pmid":"40442479","id":"PMC_40442479","title":"RBAP48 facilitates the oral squamous cell carcinoma process in an androgen receptor-dependent and independent manners.","date":"2025","source":"Communications 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letters","url":"https://pubmed.ncbi.nlm.nih.gov/24932233","citation_count":0,"is_preprint":false},{"pmid":"41930277","id":"PMC_41930277","title":"Chronic stress contributes to long-term isoflurane anesthesia-induced cognitive dysfunction via histone acetylation modulated by RbAp48-HDAC2 in male mice.","date":"2025","source":"Journal of anesthesia and translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/41930277","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.05.09.653010","title":"Functional Genomic Screens Reveal RBBP4 as a Key Regulator of Cell Cycle Progression in TMZ-Resistant Glioblastoma","date":"2025-05-10","source":"bioRxiv","url":"https://doi.org/10.1101/2025.05.09.653010","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.09.06.24313183","title":"Genome-wide association studies of Down syndrome associated congenital heart defects","date":"2024-09-06","source":"bioRxiv","url":"https://doi.org/10.1101/2024.09.06.24313183","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":33454,"output_tokens":9761,"usd":0.123388,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":19882,"output_tokens":5946,"usd":0.12403,"stage2_stop_reason":"end_turn"},"total_usd":0.247418,"stage1_batch_id":"msgbatch_01CNoDbkChHEkgrJnL7BwtGJ","stage2_batch_id":"msgbatch_016Y4x9E9Wg5VQDANj9quSQD","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"C. elegans lin-53 encodes a protein similar to RbAp48 and antagonizes Ras signaling in vulval precursor cells; lin-53 and lin-35 (Rb homolog) act in the same synthetic multivulva pathway to repress transcription of genes required for vulval cell fate expression.\",\n      \"method\": \"Genetic epistasis, loss-of-function mutant analysis, sequence homology\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with defined pathway placement and double-mutant phenotypic readout, replicated across multiple alleles in a classic model organism study\",\n      \"pmids\": [\"9875852\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Drosophila p55 (NURF55, ortholog of RbAp48) is an integral subunit of both the NURF chromatin remodeling complex and the CAF-1 chromatin assembly factor, suggesting it functions as a common platform for chromatin metabolism complexes; immunological studies confirm chromosomal association.\",\n      \"method\": \"Peptide sequencing, cDNA cloning, immunoprecipitation, immunostaining of polytene chromosomes\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal biochemical identification plus in situ localization, independently replicated in multiple complexes\",\n      \"pmids\": [\"9419341\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Purified recombinant RbAp48 binds 3–4 zinc ions per molecule, with binding activity present in both N- and C-terminal halves, suggesting metal binding is an intrinsic property of the WD-40 propeller structure that may mediate protein-protein interactions.\",\n      \"method\": \"Metal affinity chromatography, zinc blotting, atomic absorption analysis, metal competition assays\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — in vitro biochemical assay with purified protein, single lab, no functional consequence demonstrated\",\n      \"pmids\": [\"9872415\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"In Xenopus oocytes, RPD3 (HDAC) associates with RbAp48 through N- and C-terminal contacts; RbAp48 also interacts with SIN3; RbAp48 selectively binds the N-terminal tail proximal to the histone fold domain of histone H4 in vivo; RPD3 may be targeted to histones through RbAp48 to direct transcriptional repression.\",\n      \"method\": \"Xenopus oocyte microinjection, cofractionation, co-immunoprecipitation, in vivo binding assays, transcriptional repression assays\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal interactions mapped in vivo with multiple orthogonal methods (fractionation, Co-IP, transcriptional assay), single lab\",\n      \"pmids\": [\"10454532\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"RbAp48 belongs to the Rb-associated histone deacetylase complex; HDAC1 mediates formation of an Rb-RbAp48 ternary complex; cell extracts depleted of RbAp48-containing complexes show reduced deacetylase activity associated with Rb; E2F1 and RbAp48 are physically associated in the presence of Rb and HDAC1.\",\n      \"method\": \"Co-immunoprecipitation from live cells, RbAp48 immunodepletion, histone deacetylase activity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP plus functional depletion assay, two orthogonal methods in single lab\",\n      \"pmids\": [\"10734134\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"RbAp48 interacts with a CBP–phospho-CREB complex: CBP from HeLa nuclear extracts co-immunoprecipitates with RbAp48/RbAp46; RbAp48 lowers the Km of CBP histone acetyltransferase activity; RbAp48 facilitates p300-mediated in vitro transcription of a chromatinized template in an acetylCoA-dependent manner; association of core histones and mononucleosomes with the complex is acetylation-dependent.\",\n      \"method\": \"Yeast two-hybrid, Co-IP, GST pulldown, in vitro histone acetyltransferase assay (Km measurement), in vitro transcription on chromatinized template\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro enzymatic assay with Km measurement plus reconstituted transcription assay, corroborated by Co-IP, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"10866654\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"HDAC3 physically interacts with RbAp48 both in vitro and in live cells, and recruits RbAp48 to Rb; this interaction is independent of effects on Rb-E2F1 binding; RbAp48 is required for transcriptional repression of E2F activity.\",\n      \"method\": \"Co-immunoprecipitation in vivo and in vitro, transcriptional repression assays\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro and in vivo Co-IP plus functional repression assay, building on prior work with same complex\",\n      \"pmids\": [\"11470869\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Immunoaffinity proteomics of RbAp48 from Jurkat cells identified all known NuRD/Mi-2 complex proteins (including human p66) as interaction partners, plus RNA-binding/pre-mRNA splicing proteins and other novel interactors, suggesting a broader cellular role than previously documented.\",\n      \"method\": \"Immunoaffinity purification, capillary HPLC-ion-trap mass spectrometry\",\n      \"journal\": \"Journal of proteome research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — MS-based interactome from single lab, no functional follow-up for novel interactors\",\n      \"pmids\": [\"12645902\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Drosophila p55 (RbAp48 ortholog) is essential for repression of dE2F2/RBF-regulated target genes in a cell cycle-independent manner; RNAi depletion of p55 derepresses E2F targets regulated by dE2F2/RBF1 and dE2F2/RBF2, but not cell proliferation-coupled E2F targets, indicating distinct repression mechanisms at these two target classes.\",\n      \"method\": \"RNAi depletion in Drosophila cells, quantitative RT-PCR of E2F target genes, epistasis analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — RNAi loss-of-function with specific transcriptional readout across multiple target genes, epistatic dissection of two E2F repression pathways\",\n      \"pmids\": [\"15456884\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"RbAp48 overexpression induces p53-mediated apoptosis in exocrine gland cells under estrogen deficiency conditions; apoptosis requires p53 phosphorylation and E2F-1; siRNA knockdown of RbAp48 inhibits this apoptosis; transgenic RbAp48 expression induces apoptosis specifically in exocrine glands.\",\n      \"method\": \"Transgenic mouse overexpression, siRNA knockdown, Western blot for p53 phosphorylation, OVX mouse model, genetic knockout (p53−/−, E2F-1−/−, ERα−/−)\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple genetic knockouts used for epistasis, transgenic overexpression and RNAi in vivo, specific apoptotic readout\",\n      \"pmids\": [\"16581768\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"RbAp48 overexpression induces cytoskeletal reorganization (loss of actin stress fibers, formation of membranous F-actin rings, cell rounding) in breast cancer cells by increasing K-Ras-GTP levels and activating MAPK; pharmacological MAPK inhibition reverses the cytoskeletal changes; RbAp48 knockdown reduces K-Ras activity.\",\n      \"method\": \"Transfection/overexpression, siRNA knockdown, Ras activity pulldown (GTP-Ras), pharmacological MAPK inhibition, phalloidin F-actin staining\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — multiple complementary methods (overexpression, knockdown, pharmacological) in single lab, no in vitro reconstitution\",\n      \"pmids\": [\"17974974\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Crystal structure (1.9 Å) of RbAp48 bound to the 15 N-terminal amino acids of FOG-1 reveals that the FOG-1 peptide contacts a negatively charged pocket on top of the RbAp48 β-propeller, distinct from the histone H4-binding surface; RbAp48 interacts with NuRD subunit MTA-1 via a surface distinct from the FOG-binding pocket, establishing how NuRD assembly facilitates cofactor interactions.\",\n      \"method\": \"X-ray crystallography (1.9 Å), biochemical binding assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure with two distinct binding surfaces defined at high resolution, single lab with structural and biochemical orthogonal validation\",\n      \"pmids\": [\"21047798\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"The H3-H4 histone complex shows structural plasticity that facilitates allosteric exchange between RbAp48 and the histone chaperone ASF1; this exchange has a central role in new nucleosome assembly.\",\n      \"method\": \"Biochemical binding/exchange assays, mass spectrometry, EPR (ESR), structural analysis\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstitution of chaperone exchange in vitro with multiple biophysical methods (MS, EPR), single lab\",\n      \"pmids\": [\"23178455\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"RbAp48 modifies histone acetylation in the dentate gyrus (DG); dominant-negative inhibition of RbAp48 in young mouse forebrain causes hippocampus-dependent memory deficits and regionally selective decrease in histone acetylation in the DG; RbAp48 up-regulation in aged DG rescues age-related memory loss and histone acetylation abnormalities.\",\n      \"method\": \"Transgenic dominant-negative mouse, viral vector overexpression in aged mice, fMRI, novel object recognition, Morris water maze, histone acetylation measurement\",\n      \"journal\": \"Science translational medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — bidirectional (loss- and gain-of-function) in vivo experiments with matched behavioral and molecular readouts, single lab with multiple orthogonal approaches\",\n      \"pmids\": [\"23986399\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Crystal structure of RbAp48 in complex with MTA1 shows that RbAp48 binds MTA1 using the same site used to bind histone H4, demonstrating that assembly into NuRD modulates RbAp46/48 interactions with histones; MTA proteins act as scaffolds for NuRD complex assembly; the RbAp48-MTA1 interaction is essential for in vivo integration of RbAp46/48 into NuRD.\",\n      \"method\": \"X-ray crystallography, mutagenesis, co-immunoprecipitation to test in vivo integration\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus mutagenesis plus in vivo Co-IP validation, multiple orthogonal methods in single lab\",\n      \"pmids\": [\"24920672\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Crystal structure of RBBP4 bound to PHF6 peptide (residues 162-170) reveals that PHF6 contacts the top surface of the RBBP4 β-propeller via a positively charged pair of residues inserting into a negatively charged pocket; this pocket overlaps with FOG1 and histone H3 binding but is distinct from histone H4, Su(z)12, and MTA1 sites; PHF6 mutants impairing this interaction reduce PHF6-mediated transcriptional repression in vivo and RBBP4 knockdown diminishes PHF6-mediated repression.\",\n      \"method\": \"X-ray crystallography, mutagenesis, Co-IP, transcriptional reporter assay, siRNA knockdown\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus mutagenesis (in vitro and in vivo) plus functional repression assay, multiple orthogonal methods\",\n      \"pmids\": [\"25601084\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"RBBP4 depletion in mouse oocytes causes hyperacetylation of histones H3K4, H4K8, H4K12, H4K16 during meiosis I, leading to multipolar spindles at metaphase I, chromosome misalignment, and aneuploidy at metaphase II; RBBP4-mediated histone deacetylation promotes bipolar spindle assembly at least partially through Aurora kinase C (AURKC) function.\",\n      \"method\": \"siRNA depletion in mouse oocytes, immunofluorescence for spindle assembly, histone acetylation Western blot, chromosome spread analysis\",\n      \"journal\": \"Biology of reproduction\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean loss-of-function with specific molecular (histone acetylation) and cellular (spindle/aneuploidy) readouts, epistasis with AURKC\",\n      \"pmids\": [\"25788661\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"RbAp48 is essential for vertebrate cell viability; conditional knockout in chicken DT40 cells causes delayed S phase, slow DNA synthesis, impaired nascent nucleosome formation, G2/M accumulation, aberrant mitosis with highly condensed chromosomes and chromosome missegregation, dissociation of HP1 from pericentromeric heterochromatin, and elevated H3K9 acetylation with reduced H3K9 methylation.\",\n      \"method\": \"Tetracycline-inducible conditional knockout, cell cycle analysis by flow cytometry, BrdU incorporation, chromosome spread, immunostaining for HP1 and histone modifications\",\n      \"journal\": \"Chromosome research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional knockout with multiple orthogonal readouts (cell cycle, DNA synthesis, chromosome structure, epigenetic marks)\",\n      \"pmids\": [\"26667624\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"In C. elegans, LIN-53 (RbAp46/48 ortholog) is required for CENP-A(HCP-3) localization to holocentromeres; LIN-53 and CENP-A localizations are interdependent; LIN-53 localizes to the centromere during metaphase in a CENP-A- and M18BP1(KNL-2)-dependent manner; LIN-53 depletion causes anaphase bridges and chromosome missegregation; this centromeric function is independent of histone acetylation, H3K27 trimethylation, or known chromatin-modifying complexes.\",\n      \"method\": \"RNAi depletion, immunofluorescence, genetic epistasis with CENP-A and M18BP1 mutants\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — loss-of-function with multiple epistatic partners defined, specific centromeric localization phenotype, independent pathway placement\",\n      \"pmids\": [\"26904949\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"MTA1 can recruit two copies of RBBP4 simultaneously; negative stain electron microscopy and chemical crosslinking define a low-resolution model of an MTA1-(RBBP4)2 subcomplex.\",\n      \"method\": \"Biochemical binding assays, negative stain electron microscopy, chemical crosslinking/mass spectrometry\",\n      \"journal\": \"Protein science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — structural EM plus crosslinking/MS, single lab, low-resolution model\",\n      \"pmids\": [\"27144666\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"RbAp48 binds to the HIV-1 LTR in vitro and represses HIV-1 LTR-mediated basal and activated transcription; ChIP analysis shows RbAp48 occupancy at the HIV-1 LTR in cells; knockdown of RbAp48 promotes HIV infection and virus particle production.\",\n      \"method\": \"EMSA, ChIP, siRNA knockdown, HIV-1 LTR-luciferase reporter assay\",\n      \"journal\": \"International journal of molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — EMSA and ChIP plus functional knockdown, single lab\",\n      \"pmids\": [\"27222146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Crystal structure of RBBP4 in complex with BCL11A N-terminal peptide (residues 2-16) shows BCL11A contacts the side of the RBBP4 β-propeller via novel interactions distinct from histone H3; BCL11A competes with histone H3 for binding to the negatively charged top face of RBBP4; BCL11A(2-16) pulls down RBBP4, RBBP7, and components of PRC2, NuRD, and SIN3A from cell lysates.\",\n      \"method\": \"X-ray crystallography, fluorescence polarization competition assay, GST pulldown from cell lysate\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure with competition assay and pulldown validation, multiple orthogonal methods in single lab\",\n      \"pmids\": [\"29263092\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Crystal structure of RBBP4 bound to the N-terminal 14 amino acids of ZNF827 shows RBBP4 forms a negatively charged channel binding ZNF827 through electrostatic interactions; specific RBBP4 residues required for this interaction were identified and mutation prevents RBBP4 binding to both ZNF827 and telomeres, establishing how NuRD is recruited to ALT telomeres via ZNF827.\",\n      \"method\": \"X-ray crystallography, mutagenesis, ChIP, Co-IP\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus structure-guided mutagenesis validated by ChIP, multiple orthogonal methods\",\n      \"pmids\": [\"30045876\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"RbAp48 controls expression of BDNF and GPR158 (components of osteocalcin signaling) in mouse hippocampus; inhibition of RbAp48 in hippocampal formation blocks OCN's beneficial effects on cognition and causes discrimination memory deficits; disruption of OCN/GPR158 signaling downregulates RbAp48, creating a feedback loop; activation of OCN/GPR158 increases RbAp48 expression in aged DG and rescues age-related memory loss.\",\n      \"method\": \"Viral vector RbAp48 inhibition in vivo, GPR158 pharmacological blockade, gene expression analysis, behavioral memory tests\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — bidirectional in vivo manipulation with molecular and behavioral readouts, single lab\",\n      \"pmids\": [\"30355501\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"LIN-53 (RBBP4/7 ortholog) interacts with the NuRD complex in C. elegans muscles to maintain muscle integrity; LIN-53 also interacts with the SIN3 HDAC complex required for normal lifespan; lin-53 and sin-3 mutants show decreased trehalose levels; trehalose supplementation or enhancement via insulin/IGF1 signaling rescues lifespan defects.\",\n      \"method\": \"Genetic mutant analysis, transcriptomics, metabolomics, epistasis with trehalose feeding and insulin pathway\",\n      \"journal\": \"Aging cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic and metabolomic epistasis with rescue experiments, single lab\",\n      \"pmids\": [\"31397537\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"RBBP4 loss in mouse embryos causes hyperacetylated histones and severe apoptosis in blastocysts; trophoblast lineage is properly specified but epiblast and primitive endoderm are compromised; RBBP4 is essential for early mouse embryogenesis and inner cell mass formation.\",\n      \"method\": \"Conditional knockout mouse, blastocyst outgrowth assay, immunofluorescence for lineage markers and histone acetylation, TUNEL apoptosis assay\",\n      \"journal\": \"Biology of reproduction\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo knockout with lineage specification analysis and histone modification readout, multiple orthogonal methods\",\n      \"pmids\": [\"32285100\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Structure-based design of bicyclic peptide inhibitors targeting the RbAp48/MTA1 protein-protein interaction interface achieves nanomolar affinity (KD = 8.56 nM); crystallographic analysis guided affinity optimization via hydrophobic aromatic linker interactions with a hydrophobic residue on RbAp48.\",\n      \"method\": \"X-ray crystallography, fluorescence polarization/binding affinity measurement, protease stability assay\",\n      \"journal\": \"Angewandte Chemie (International ed. in English)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure-guided design with quantitative binding measurement and stability assay\",\n      \"pmids\": [\"33022847\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Double knockdown of Rbbp4 and Rbbp7 (but not individually) causes embryonic lethality at morula-to-blastocyst transition with cell cycle block, disrupted lineage specification, and a dramatic increase in histone H3.3 and H3K27ac; ChIP-seq shows RBBP4/7 target gene promoters are enriched for H3.3; RBBP4/7 regulate H3.3 deposition epigenetically.\",\n      \"method\": \"siRNA double knockdown in mouse embryos, ChIP-seq for H3.3, RNA-seq, immunofluorescence\",\n      \"journal\": \"Epigenetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genome-wide ChIP-seq plus RNA-seq plus phenotypic analysis, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"34709113\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"RBBP4 deficiency in mouse ESCs causes spontaneous differentiation into mesendodermal lineages; RBBP4 is essential for PRC2 genomic targeting to a subset of developmental genes; RBBP4 sustains Oct4 and Sox2 expression; forced co-expression of Oct4 and Sox2 fully rescues pluripotency in Rbbp4-null ESCs.\",\n      \"method\": \"Knockout ESCs, RNA-seq, ChIP-seq for PRC2 components, rescue by Oct4/Sox2 overexpression\",\n      \"journal\": \"Stem cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — knockout plus genome-wide ChIP-seq plus epistatic rescue, multiple orthogonal approaches\",\n      \"pmids\": [\"33606987\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"In Tetrahymena, the RBBP4/7 ortholog RebL1 physically interacts with histone H4 and co-purifies with subunits of CAF1, Hat1, Rpd3, and MuvB complexes; RebL1 is a component of a MuvB-like complex containing Lin54, Lin9, and RebL1; RebL1 and Lin54 bind genic and intergenic regions genome-wide; RebL1 depletion suppresses Rad51 expression, consistent with DNA repair roles.\",\n      \"method\": \"Affinity purification/mass spectrometry, ChIP-seq, RNAi depletion, Western blot\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — AP-MS plus ChIP-seq plus functional depletion, single lab\",\n      \"pmids\": [\"34086947\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"RBBP4 forms a complex with p300 histone acetyltransferase in the nucleus of GBM cells (demonstrated by proximity ligation assay); ChIP-seq shows co-occupancy of RBBP4/p300 at promoters/enhancers with H3K27ac; RBBP4 and p300 co-regulate 1,485 genes including C-MYC; RBBP4 or p300 knockdown sensitizes GBM cells to temozolomide.\",\n      \"method\": \"Proximity ligation assay, ChIP-seq, shRNA knockdown, RNA-seq, in vivo orthotopic tumor model\",\n      \"journal\": \"Neuro-oncology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — PLA for complex formation plus ChIP-seq co-occupancy plus in vivo functional validation, multiple orthogonal methods\",\n      \"pmids\": [\"35231103\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"RBBP4 loss in zebrafish disrupts neural progenitor cell cycle progression independent of Rb1 (rbbp4; rb1 double mutants show additive M-phase accumulation); Rbbp4 loss leads to Tp53 acetylation and Tp53-dependent apoptosis in developing brain; Tp53 knockdown/knockout suppresses apoptosis in rbbp4 mutants.\",\n      \"method\": \"Zebrafish genetic mutant analysis (rbbp4, rb1, tp53 mutants), immunofluorescence for γ-H2AX and M-phase markers, epistasis with tp53 morpholino/knockout\",\n      \"journal\": \"Developmental dynamics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic epistasis with double mutants, specific molecular readout (Tp53 acetylation), rescue experiments\",\n      \"pmids\": [\"35266256\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Photoaffinity labeling identified RBBP4 as a direct cellular target of protopanaxadiol (PPD) in HCT116 colorectal cancer cells; PPD binding to RBBP4 decreases RBBP4-dependent H3K27me3; PPD inhibition of cell proliferation/migration is antagonized by RBBP4 silencing, confirming RBBP4 as a functional target.\",\n      \"method\": \"Photoaffinity labeling chemoproteomic pulldown, H3K27me3 Western blot, siRNA knockdown rescue\",\n      \"journal\": \"Chembiochem\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — cell-permeable probe pulldown with functional rescue, single lab\",\n      \"pmids\": [\"35442561\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"RBBP4 recruits transcription factors and epigenetic regulators to the promoters of MRN complex genes (Mre11, Rad50, NBS1) to regulate their expression and thereby controls DNA double-strand break repair; RBBP4 disruption increases DNA damage sensitivity to TMZ and radiotherapy in GBM cells.\",\n      \"method\": \"ChIP-seq, shRNA knockdown, γ-H2AX assay, cell proliferation assays\",\n      \"journal\": \"Cancer letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — ChIP plus functional knockdown, single lab\",\n      \"pmids\": [\"36736531\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"RBBP4 functions as an epigenetic barrier to totipotency: it binds endogenous retroviruses (ERVs) and recruits G9a to deposit H3K9me2 on ERVL elements and recruits KAP1 to deposit H3K9me3 on ERV1/ERVK elements; RBBP4 also facilitates nucleosome occupancy at ERVK/ERVL sites in heterochromatin via chromatin remodeler CHD4; RBBP4 depletion activates transposable elements and 2C genes, reprogramming ESCs toward totipotency.\",\n      \"method\": \"Auxin-induced degron depletion, ChIP-seq for H3K9me2/me3 and nucleosome occupancy (ATAC-seq), Co-IP for G9a/KAP1/CHD4, RNA-seq\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — rapid depletion system with genome-wide ChIP-seq plus Co-IP plus multiple epigenetic marks, mechanistically comprehensive single study\",\n      \"pmids\": [\"37021556\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ZNF512B contains a variant NuRD-interaction motif (NIM) that binds RBBP4; crystal structure of this ZNF512B NIM bound to RBBP4 demonstrates it is necessary and sufficient for high-affinity NuRD binding; ZNF512B recruits NuRD through RBBP4 to repress gene expression.\",\n      \"method\": \"X-ray crystallography, biochemical binding assays, mutagenesis, transcriptome analysis, reporter assays\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus mutagenesis validation plus functional transcriptional assay, multiple orthogonal methods\",\n      \"pmids\": [\"39460621\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"RBBP4 knockdown in mouse E12.5 neocortical progenitors reduces neuronal output, specifically affecting CTIP2-expressing deep-layer neurons; RBBP4 genome-wide occupancy is primarily at distal regulatory elements; RBBP4 binds the Cdon gene (Shh pathway receptor); Cdon knockdown phenocopies RBBP4 knockdown; CDON overexpression rescues neurogenesis defects caused by RBBP4 loss.\",\n      \"method\": \"CRISPR/Cas9 knockdown in embryonic neocortex, ChIP-seq, immunofluorescence for neuronal markers, rescue by CDON overexpression\",\n      \"journal\": \"eNeuro\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP-seq plus phenotypic rescue experiment plus loss-of-function, multiple orthogonal methods identifying target gene\",\n      \"pmids\": [\"39592227\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In chronic stress/isoflurane anesthesia cognitive impairment, RbAp48 interacts with HDAC2 (demonstrated by Co-IP); chronic stress reduces RbAp48 expression and increases HDAC2 levels and their interaction, decreasing H3K9ac and H4K12ac; RbAp48 overexpression restores histone acetylation, increases BDNF, and rescues memory deficits.\",\n      \"method\": \"Co-immunoprecipitation, Western blot, adenoviral RbAp48 overexpression in vivo and in vitro, fear conditioning behavioral test\",\n      \"journal\": \"Journal of anesthesia and translational medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — Co-IP plus rescue experiment, single lab, no independent replication\",\n      \"pmids\": [\"41930277\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"RBBP4 knockout in TMZ-resistant glioblastoma cells (identified by CRISPR functional genomic screen using epigenetic knockout library) significantly impairs cell proliferation without affecting MGMT expression; RBBP4 loss downregulates G2/M checkpoint cell cycle genes and causes increased cell size and multinucleation indicative of disrupted mitotic progression.\",\n      \"method\": \"CRISPR/Cas9 dropout screen, RNA-seq after RBBP4 KO, live-cell imaging, immunofluorescence\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — unbiased functional genomic screen plus transcriptomics plus cell imaging, preprint not peer-reviewed\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"RBBP4 (RbAp48) is a WD-40 repeat histone chaperone that serves as a scaffold subunit of multiple chromatin-modifying complexes (NuRD, PRC2, CAF-1, NURF, SIN3A, CoREST), binding histone H4 via its β-propeller top face and recruiting HDACs (HDAC1/2/3) and histone acetyltransferases (CBP/p300) to regulate transcription; structural studies have defined distinct binding surfaces on the β-propeller for histone H4, histone H3, MTA1/NuRD assembly, and transcriptional cofactors (FOG-1, PHF6, BCL11A, ZNF827, ZNF512B), with MTA1 binding occluding the histone H4 site; functionally, RBBP4 is required for heterochromatin maintenance (H3K9me2/3 deposition via G9a/KAP1 at ERV loci), centromere assembly, cell cycle progression (especially G2/M), histone deacetylation during meiosis, nucleosome assembly via histone H3-H4 chaperone exchange with ASF1, PRC2 genomic targeting in stem cells, and neural progenitor differentiation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"RBBP4 (RbAp48) is a WD-40 β-propeller histone chaperone that functions as a shared scaffold subunit of multiple chromatin-modifying complexes, coupling histone binding to transcriptional repression and chromatin assembly [#1, #3]. It selectively binds the N-terminal tail of histone H4 in vivo and serves as a common platform for the NURF remodeling and CAF-1 assembly complexes [#1, #3], and biophysical reconstitution shows it participates in allosteric H3-H4 exchange with the chaperone ASF1 during new nucleosome assembly [#12]. RBBP4 targets histone deacetylase activity to chromatin: it associates with RPD3/HDAC1, HDAC3, and SIN3 to direct deacetylation and transcriptional repression, including repression downstream of Rb/E2F [#3, #4, #6], and it interacts with HDAC2 and with the CBP/p300 acetyltransferases—lowering the Km of CBP and facilitating p300-dependent transcription on chromatinized templates—positioning it at both ends of the histone acetylation cycle [#5, #30, #37]. A series of crystal structures define how distinct surfaces of the β-propeller engage histones versus cofactors: the top face binds a negatively charged pocket used by FOG-1, histone H3, and PHF6, the side surface is contacted by BCL11A and ZNF827, and the histone H4 site is occluded when MTA1 binds, with MTA1 acting as the scaffold that integrates RBBP4 into NuRD and can recruit two RBBP4 copies [#11, #14, #15, #19, #21, #22, #35]. Through these interactions RBBP4 enforces heterochromatin and developmental gene silencing: it recruits G9a and KAP1 to deposit H3K9me2/me3 at endogenous retroviruses and acts as an epigenetic barrier to totipotency [#34], directs PRC2 genomic targeting in embryonic stem cells to sustain pluripotency via Oct4/Sox2 [#28], and is required for histone deacetylation during oocyte meiosis, embryogenesis, cell cycle progression, and centromere/CENP-A assembly [#16, #17, #18, #25]. RBBP4 is essential for vertebrate cell viability and proper mitosis, with loss causing G2/M accumulation, impaired nucleosome formation, chromosome missegregation, and Tp53-dependent apoptosis [#17, #31]. In the nervous system it controls hippocampal histone acetylation and BDNF/GPR158 signaling required for memory [#13, #23], and it drives neural progenitor differentiation by binding distal regulatory elements at target genes such as Cdon [#36].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Established that the RBBP4 ortholog is a transcriptional repressor acting genetically with the Rb pathway and is a physical subunit of distinct chromatin machines, defining it as a shared chromatin platform rather than a single-complex factor.\",\n      \"evidence\": \"C. elegans genetic epistasis (lin-53/lin-35) and Drosophila p55 biochemical purification from NURF and CAF-1 with polytene chromosome localization\",\n      \"pmids\": [\"9875852\", \"9419341\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of histone or complex recognition not yet defined\", \"Direct enzymatic partners not yet identified\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Showed RBBP4 selectively binds the histone H4 N-terminal tail in vivo and bridges HDAC (RPD3) and SIN3 to chromatin, establishing it as the targeting subunit that delivers deacetylase activity for repression.\",\n      \"evidence\": \"Xenopus oocyte microinjection, cofractionation, Co-IP, and transcriptional repression assays\",\n      \"pmids\": [\"10454532\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of H4 recognition not resolved\", \"Did not distinguish which complexes use this interaction in cells\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Connected RBBP4 to both histone deacetylation (Rb-HDAC1 ternary complex) and histone acetylation (lowering CBP/p300 Km and enabling chromatin transcription), placing it at both poles of the acetylation cycle.\",\n      \"evidence\": \"Co-IP plus RbAp48 immunodepletion deacetylase assays, and yeast two-hybrid/GST pulldown with in vitro HAT and chromatin transcription assays\",\n      \"pmids\": [\"10734134\", \"10866654\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How a single scaffold partitions between HAT and HDAC complexes in vivo unresolved\", \"In vitro Km effects not validated genome-wide\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Extended the HDAC repertoire to HDAC3 recruited to Rb and showed RBBP4 is functionally required for E2F repression, generalizing its role across deacetylases.\",\n      \"evidence\": \"In vitro and in vivo Co-IP plus transcriptional repression assays\",\n      \"pmids\": [\"11470869\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Selectivity between HDAC1/2/3 complexes not defined\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Defined the RBBP4 interactome as encompassing the complete NuRD/Mi-2 complex plus RNA-processing factors, broadening its documented cellular role.\",\n      \"evidence\": \"Immunoaffinity purification with capillary HPLC-ion-trap mass spectrometry from Jurkat cells\",\n      \"pmids\": [\"12645902\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Novel splicing-factor interactors never functionally validated\", \"MS interactome from a single cell type\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Linked RBBP4 dosage to cytoplasmic signaling and apoptosis (K-Ras/MAPK activation, p53-dependent apoptosis), raising non-chromatin or indirect functions.\",\n      \"evidence\": \"Transgenic overexpression, siRNA, Ras-GTP pulldown, pharmacological MAPK inhibition, and genetic knockout epistasis in mouse models\",\n      \"pmids\": [\"16581768\", \"17974974\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting a nuclear chaperone to cytoplasmic Ras activity not established\", \"No in vitro reconstitution of the signaling link\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Resolved how RBBP4 hands off histones, demonstrating allosteric H3-H4 exchange with ASF1 central to new nucleosome assembly.\",\n      \"evidence\": \"Reconstituted in vitro chaperone exchange assays with mass spectrometry, EPR, and structural analysis\",\n      \"pmids\": [\"23178455\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Coupling of this exchange to specific assembly complexes (CAF-1) in vivo not shown\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined the structural logic of the β-propeller as a multi-surface hub: the top-face pocket (FOG-1, H3, PHF6) is mutually exclusive with cofactors, while MTA1 binding occludes the histone H4 site to integrate RBBP4 into NuRD.\",\n      \"evidence\": \"Crystal structures of RBBP4 with FOG-1, MTA1, and PHF6 peptides, with mutagenesis, competition assays, Co-IP, and reporter assays\",\n      \"pmids\": [\"21047798\", \"24920672\", \"25601084\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How competition is regulated dynamically in cells not addressed\", \"Stoichiometry within intact complexes not fully resolved\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Established assembly architecture (MTA1 recruiting two RBBP4 copies) and an acetylation-independent centromeric function requiring CENP-A and M18BP1, revealing roles beyond chromatin modification.\",\n      \"evidence\": \"Negative-stain EM/crosslinking of MTA1-(RBBP4)2, and C. elegans RNAi with CENP-A/M18BP1 epistasis and immunofluorescence\",\n      \"pmids\": [\"27144666\", \"26904949\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"High-resolution NuRD subcomplex structure lacking\", \"Molecular mechanism of centromeric CENP-A loading by RBBP4 unknown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Implicated RBBP4 in meiotic genome stability and in viral transcriptional control, broadening its functional reach.\",\n      \"evidence\": \"siRNA depletion in mouse oocytes with spindle/aneuploidy and histone acetylation readouts and AURKC epistasis; EMSA, ChIP, and LTR reporter assays for HIV-1\",\n      \"pmids\": [\"25788661\", \"27222146\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct deacetylase complex responsible for meiotic deacetylation not pinpointed\", \"HIV LTR repression mechanism is correlative (single lab)\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Demonstrated that RBBP4 is essential for vertebrate viability with intertwined defects in S-phase, nucleosome assembly, mitosis, and heterochromatin maintenance.\",\n      \"evidence\": \"Tetracycline-inducible conditional knockout in chicken DT40 cells with cell-cycle, BrdU, chromosome, and HP1/histone-mark analyses\",\n      \"pmids\": [\"26667624\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which downstream defect is primary versus secondary not dissected\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Extended structural recruitment principles to the propeller side surface (BCL11A, ZNF827) and showed ZNF827 directs NuRD to ALT telomeres, generalizing the cofactor-recruitment paradigm.\",\n      \"evidence\": \"Crystal structures of RBBP4 with BCL11A and ZNF827 peptides with competition assays, structure-guided mutagenesis, ChIP, and Co-IP\",\n      \"pmids\": [\"29263092\", \"30045876\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo selectivity among competing top-face/side-face ligands not resolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Defined a hippocampal RBBP4 program controlling histone acetylation and BDNF/GPR158 osteocalcin signaling required for memory and reversible in aging.\",\n      \"evidence\": \"Dominant-negative transgenic and viral overexpression mice with fMRI, behavioral memory tests, and histone acetylation measurements; pharmacological GPR158 blockade\",\n      \"pmids\": [\"23986399\", \"30355501\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Chromatin complex mediating DG-specific acetylation changes not identified\", \"Direct versus systemic contributions to memory not separated\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Showed RBBP4 (and redundantly RBBP7) is essential for early embryogenesis, restraining histone acetylation and H3.3 deposition to permit lineage specification.\",\n      \"evidence\": \"Conditional knockout and siRNA double-knockdown mouse embryos with lineage marker immunofluorescence, TUNEL, ChIP-seq for H3.3, and RNA-seq\",\n      \"pmids\": [\"32285100\", \"34709113\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Degree of RBBP4/RBBP7 redundancy in somatic tissues not quantified\", \"Mechanism restraining H3.3 deposition not biochemically defined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Established RBBP4 as required for PRC2 genomic targeting and pluripotency maintenance in ESCs, with the differentiation phenotype rescued by Oct4/Sox2.\",\n      \"evidence\": \"Knockout ESCs with RNA-seq, PRC2 ChIP-seq, and epistatic rescue by Oct4/Sox2 overexpression\",\n      \"pmids\": [\"33606987\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How RBBP4 directs PRC2 to a specific gene subset mechanistically unclear\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined RBBP4 as an epigenetic barrier to totipotency, recruiting G9a and KAP1 to deposit H3K9me2/me3 at ERVs and using CHD4 for nucleosome occupancy in heterochromatin.\",\n      \"evidence\": \"Auxin-induced degron depletion with ChIP-seq for H3K9me2/me3, ATAC-seq, Co-IP for G9a/KAP1/CHD4, and RNA-seq\",\n      \"pmids\": [\"37021556\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How RBBP4 selects ERV families for distinct methyltransferases not resolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Refined the cofactor-recruitment model with a variant NuRD-interaction motif in ZNF512B and identified a distal-enhancer-driven neural differentiation program acting through the Shh receptor Cdon.\",\n      \"evidence\": \"Crystal structure of ZNF512B NIM-RBBP4 with mutagenesis and transcriptome/reporter assays; CRISPR knockdown of RBBP4 in neocortical progenitors with ChIP-seq and CDON rescue\",\n      \"pmids\": [\"39460621\", \"39592227\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Generality of variant NIMs across other NuRD recruiters untested\", \"How RBBP4 selects deep-layer neuron genes not defined\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Implicated RBBP4 as a targetable dependency in glioblastoma, co-occupying H3K27ac chromatin with p300 and regulating DNA repair (MRN) and cell cycle genes to influence therapy resistance.\",\n      \"evidence\": \"Proximity ligation assay, ChIP-seq, shRNA/CRISPR knockdown, RNA-seq, γ-H2AX assays, and orthotopic tumor models\",\n      \"pmids\": [\"35231103\", \"36736531\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct versus indirect control of MRN/repair genes not separated\", \"p300 cofactor mechanism is correlative at most loci\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How RBBP4 dynamically partitions among its many mutually exclusive cofactors and complexes to achieve locus- and lineage-specific outcomes, and the structural basis of its acetylation-independent centromeric function, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No quantitative model of complex occupancy in vivo\", \"High-resolution structure of RBBP4 within intact NuRD/PRC2 lacking\", \"Mechanism of CENP-A-dependent centromere loading unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0042393\", \"supporting_discovery_ids\": [3, 11, 12, 14, 15]},\n      {\"term_id\": \"GO:0044183\", \"supporting_discovery_ids\": [12, 1]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [11, 14, 22, 35]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [3, 8, 28, 34]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1, 3, 30]},\n      {\"term_id\": \"GO:0000228\", \"supporting_discovery_ids\": [1, 17, 34]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [1, 3, 34]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [3, 8, 28]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [4, 17, 38]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [25, 28, 36]}\n    ],\n    \"complexes\": [\"NuRD\", \"CAF-1\", \"NURF\", \"PRC2\"],\n    \"partners\": [\"MTA1\", \"HDAC1\", \"CBP/p300\", \"PHF6\", \"BCL11A\", \"ZNF827\", \"ASF1\", \"G9a\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}