{"gene":"MORF4L1","run_date":"2026-04-28T18:30:28","timeline":{"discoveries":[{"year":2006,"finding":"Crystal structure of human MRG15 chromodomain at 2.2 Å resolution reveals a beta-barrel with a hydrophobic pocket formed by Tyr26, Tyr46, and Trp49 that binds methylated H3K36 but not methylated H3K4, H3K9, or H3K27, demonstrating selective methyl-lysine reading activity.","method":"X-ray crystallography + in vitro peptide binding assay","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 — crystal structure with functional binding validation","pmids":["17135209"],"is_preprint":false},{"year":2001,"finding":"MRG15 forms a multiprotein complex with retinoblastoma protein (Rb) and the novel nuclear protein PAM14, mediated by the helix-loop-helix and leucine zipper domains of MRG15, and this complex activates the B-myb promoter by blocking Rb-induced repression.","method":"Co-immunoprecipitation, yeast two-hybrid, domain deletion mapping, promoter-reporter assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP with domain mapping and functional reporter assay","pmids":["11500496"],"is_preprint":false},{"year":2002,"finding":"MRG15 exists in two distinct nuclear protein complexes: MAF1 (containing Rb and PAM14, requiring the leucine zipper) and MAF2 (containing the histone acetyltransferase hMOF, requiring the chromodomain); histone acetyltransferase activity co-purifies with MRG15 and is lost upon chromodomain deletion.","method":"Sucrose gradient fractionation, deletion mutant analysis, histone acetyltransferase activity assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — biochemical fractionation with domain mapping and enzymatic assay","pmids":["12397079"],"is_preprint":false},{"year":2002,"finding":"MRG15, MRGX, and MORF4 repress transcription through direct association with mSin3A and TLE (Transducin-Like Enhancer of Split) histone deacetylase-containing corepressors; MRG15 uniquely interacts with Pf1, which reduces MRG15-mediated repression through an MRG15/Pf1/mSin3A complex.","method":"Gal4-luciferase reporter assay, Co-immunoprecipitation, domain mapping, dominant-negative TLE","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods including Co-IP, reporter assay, and dominant-negative genetics","pmids":["12391155"],"is_preprint":false},{"year":2005,"finding":"MRG15 knockout mice display embryonic lethality with developmental delay, reduced cell proliferation in multiple tissues without increased apoptosis, and MRG15 is recruited to the alpha-globin promoter during erythroid differentiation as shown by chromatin immunoprecipitation.","method":"Knockout mouse generation, BrdU proliferation assay, chromatin immunoprecipitation (ChIP)","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 — clean KO with defined cellular phenotype and direct ChIP localization","pmids":["15798182"],"is_preprint":false},{"year":2006,"finding":"Crystal structure of the MRG domain of MRG15 reveals a predominantly alpha-helical three-layer sandwich topology; structure-based mutagenesis identified Ile160, Leu168, Val169, Trp172, Tyr235, Val268, and Arg269 as forming a shallow hydrophobic pocket mediating interaction with the N-terminal 50 residues of PAM14.","method":"X-ray crystallography, site-directed mutagenesis, yeast two-hybrid, in vitro binding assay","journal":"Protein science","confidence":"High","confidence_rationale":"Tier 1 — crystal structure with mutagenesis and functional binding validation","pmids":["17008723"],"is_preprint":false},{"year":2007,"finding":"MRG15 complex contains RBP2 (a JmjC domain H3K4 demethylase); RBP2 associated with MRG15 removes H3K4 methylation within transcribed regions in vivo, and MRG15 localizes to nuclear subdomains enriched for Ser2-phosphorylated RNA Pol II.","method":"Co-immunoprecipitation, mass spectrometry, in vitro demethylase assay, RBP2 knockdown, nuclear fractionation/immunostaining","journal":"Genes to cells","confidence":"High","confidence_rationale":"Tier 1-2 — in vitro enzymatic assay + reciprocal Co-IP + KD with epigenetic readout","pmids":["17573780"],"is_preprint":false},{"year":2009,"finding":"MRG15 directly binds PALB2 via an evolutionarily conserved region; disruption of this interaction elevates gene conversion rates and sister chromatid exchange frequencies, indicating MRG15 suppresses hyper-recombination during homologous recombination repair.","method":"Co-immunoprecipitation, pulldown, gene conversion assay, SCE assay, point-mutation of binding interface","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — direct binding identified with functional genetic consequence in two orthogonal assays","pmids":["19553677"],"is_preprint":false},{"year":2010,"finding":"MRG15 directly binds PALB2 and mediates the association of the entire BRCA complex (BRCA1, PALB2, BRCA2, RAD51) with chromatin; MRG15-deficient cells show reduced homology-directed DNA repair, hypersensitivity to interstrand crosslinking agents, and impaired recruitment of PALB2, BRCA2, and RAD51 to DNA damage sites.","method":"Purified protein complex analysis, Co-immunoprecipitation, homology-directed repair assay, ICL sensitivity assay, immunofluorescence of repair foci, chromatin fractionation","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods with clean KD and defined DNA repair phenotypes","pmids":["20332121"],"is_preprint":false},{"year":2007,"finding":"Mrg15-null and heterozygous mouse embryonic fibroblasts exhibit delayed formation of phosphorylated H2AX and 53BP1 foci and impaired DNA repair after gamma irradiation, establishing MRG15 as required for efficient DNA damage response.","method":"Gamma irradiation of KO MEFs, immunofluorescence for γH2AX and 53BP1 foci, cell growth assay","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 — clean KO with defined damage-response phenotype, single lab","pmids":["17961556"],"is_preprint":false},{"year":2011,"finding":"MRG15 occupies the cdc2 (CDK1) promoter during S phase entry and cooperates with Tip60 HAT to acetylate histone H4 (specifically H4K12) at this promoter, activating cdc2 transcription; knockdown of MRG15 reduces cdc2 promoter activity.","method":"Chromatin immunoprecipitation (ChIP), promoter-reporter assay, HAT inhibitor treatment, co-transfection","journal":"Experimental cell research","confidence":"Medium","confidence_rationale":"Tier 2-3 — ChIP with functional reporter and pharmacological evidence, single lab","pmids":["21324423"],"is_preprint":false},{"year":2011,"finding":"The mSin3A PAH2 domain interacts with the Pf1 SID1 motif in a manner similar to Mad1/Mxd1; MRG15 competes with mSin3A for binding to Pf1, implying mutual exclusivity of two subunits within the Rpd3S/Sin3S complex for Pf1.","method":"NMR solution structure, pulldown assay, competitive binding assay","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1 — NMR structure with functional competition binding assays","pmids":["21440557"],"is_preprint":false},{"year":2012,"finding":"MRG15 chromodomain binds H3K36me2/3 with >100 µM affinity and Pf1 PHD1 binds unmodified H3K4 with similarly low affinity; both domains are required together for bivalent (non-cooperative) targeting of the Rpd3S/Sin3S complex to chromatin; Pf1 PHD1 also engages the MRG15 MRG domain.","method":"In vitro peptide binding assay, isothermal titration calorimetry, pulldown, domain deletion analysis","journal":"Journal of molecular biology","confidence":"High","confidence_rationale":"Tier 1-2 — quantitative binding measurements with domain mutagenesis, multiple orthogonal assays","pmids":["22728643"],"is_preprint":false},{"year":2014,"finding":"HDAC2 deacetylates MORF4L1 at Lys-148, and this deacetylation is required for MORF4L1 homodimerization; acetylation mimics (K148L, K148Q) abolish self-assembly, while Lys-to-Arg substitution (mimicking deacetylation) promotes it; HDAC2 knockdown reduces MORF4L1 homodimerization.","method":"Co-immunoprecipitation, site-directed mutagenesis (K148R, K148L, K148Q), HDAC2 knockdown","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — mutagenesis of modification site with KD validation, multiple mutants","pmids":["24451372"],"is_preprint":false},{"year":2017,"finding":"MRG15 (Mrg15 in Drosophila) is a subunit of the Ash1 histone methyltransferase complex that stimulates Ash1 H3K36 methyltransferase activity in vitro; Mrg15 is recruited by Ash1 to common genomic targets and reinforces Ash1 chromatin association; an Ash1 point mutation (R1288A) that reduces Mrg15 interaction causes homeotic transformations partially rescued by Mrg15-Nurf55 fusion.","method":"In vitro methyltransferase assay, ChIP, genetic knock-in, co-immunoprecipitation, rescue experiment","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1-2 — in vitro enzymatic assay + genetic epistasis + ChIP + multiple orthogonal methods","pmids":["29158494"],"is_preprint":false},{"year":2017,"finding":"PALB2 associates with active genes through MRG15, which recognizes H3K36me3 deposited by SETD2; PALB2-MRG15 binding-defective missense mutations increase sensitivity to camptothecin and elevate DNA stress in gene bodies during replication, establishing a SETD2/H3K36me3/MRG15/PALB2 axis that protects active genes.","method":"ChIP-seq, missense mutation analysis, camptothecin sensitivity assay, metaphase chromosome analysis, DNA combing","journal":"Proceedings of the National Academy of Sciences","confidence":"High","confidence_rationale":"Tier 2 — genome-wide ChIP-seq with functional mutations and multiple phenotypic readouts","pmids":["28673974"],"is_preprint":false},{"year":2016,"finding":"MRG15 is required for pre-mRNA splicing during spermatogenesis; it binds H3K36me3 in introns of transcriptionally active genes and colocalizes with splicing factors PTBP1 and PTBP2 at H3K36me3 sites in round spermatids; conditional KO causes intron retention in transition protein mRNAs and spermatogenic arrest.","method":"Conditional KO mouse, RNA-seq, ChIP, co-immunofluorescence of splicing factors","journal":"Proceedings of the National Academy of Sciences","confidence":"High","confidence_rationale":"Tier 2 — clean conditional KO with RNA-seq, ChIP, and colocalization","pmids":["27573846"],"is_preprint":false},{"year":2019,"finding":"Crystal structure of human ASH1L tandem MID-SET domains in complex with MRG15 MRG domain reveals that MRG15 binds a conserved FxLP motif N-terminal to the ASH1L SET domain and displaces the autoinhibitory post-SET loop to open the substrate binding pocket, activating H3K36 methyltransferase activity.","method":"X-ray crystallography, in vitro methyltransferase assay, mutagenesis","journal":"Structure","confidence":"High","confidence_rationale":"Tier 1 — crystal structure with enzymatic activity and mutagenesis, replicated by two independent groups same year","pmids":["30827841","30827843"],"is_preprint":false},{"year":2019,"finding":"Crystal structure of Ash1L MID-SET domains bound to MRG15 MRG domain shows that MRG15 binding induces subtle structural changes in the SAM-binding pocket of ASH1L via a conserved interaction segment, implicating conformational coupling between SAM and substrate binding sites as the activation mechanism.","method":"X-ray crystallography, in vitro methyltransferase assay","journal":"Structure","confidence":"High","confidence_rationale":"Tier 1 — crystal structure with functional validation, independent replication of Ash1L-MRG15 structure","pmids":["30827843"],"is_preprint":false},{"year":2020,"finding":"MRG15 genomic recruitment shows significant diurnal rhythm in mouse liver and activates lipid synthesis genes; MRG15 interacts with nuclear receptor LRH-1 (not core clock proteins) and is recruited to lipid gene loci via LRH-1; MRG15 depletion impairs rhythmic Pol II recruitment and histone acetylation at lipid genes.","method":"ChIP-seq, Co-immunoprecipitation, CRISPR targeting, RNA-seq, luciferase reporter","journal":"Nature metabolism","confidence":"High","confidence_rationale":"Tier 2 — ChIP-seq with Co-IP and CRISPR KO, multiple phenotypic readouts","pmids":["32694659"],"is_preprint":false},{"year":2021,"finding":"Crystal structure of the MRG15 MRG domain bound to PALB2 peptide shows PALB2 interacts with an extended surface of MRG15 with nanomolar affinity; this binding region overlaps with sites for other MRG15 partners, indicating mutually exclusive binding; breast cancer-derived PALB2 mutations cause only minor affinity reduction.","method":"X-ray crystallography, surface plasmon resonance/binding affinity measurement, PALB2 variant analysis","journal":"Genes","confidence":"High","confidence_rationale":"Tier 1 — crystal structure with quantitative binding measurements","pmids":["34946951"],"is_preprint":false},{"year":2022,"finding":"MRG15 associates with the outer mitochondrial membrane and interacts with and deacetylates TUFM at K82 and K91; deacetylated TUFM is targeted for degradation by the mitochondrial ClpXP protease, resulting in impaired mitophagy, increased oxidative stress, and NLRP3 inflammasome activation in NASH; inflammatory cytokines increase MRG15 acetylation to stabilize MRG15 in this context.","method":"Immunoprecipitation-mass spectrometry, co-immunoprecipitation, CRISPR targeting, mitochondrial fractionation, mitophagy assay, NLRP3 activation assay","journal":"Journal of hepatology","confidence":"High","confidence_rationale":"Tier 2 — IP-MS with orthogonal Co-IP, CRISPR KO, and multiple mechanistic readouts in vivo and in vitro","pmids":["35985547"],"is_preprint":false},{"year":2023,"finding":"MRG15, once activating ASH1L, recruits the ASH1L-MRG15 complex to nucleosome substrates via the MRG15 chromodomain; full-length MRG15 but not the MRG domain alone enhances ASH1L SET domain activity; MRG15 does not alter the conformation of the ASH1L autoinhibitory loop or SAM binding site in solution, suggesting MRG15 functions as a nucleosome-recruiting adapter rather than purely an allosteric activator.","method":"In vitro methyltransferase assay with nucleosomes, NMR, pulldown, chromodomain binding assay","journal":"Structure","confidence":"High","confidence_rationale":"Tier 1 — in vitro reconstituted enzymatic assay with NMR structural analysis and domain dissection","pmids":["37527654"],"is_preprint":false},{"year":2023,"finding":"Upon UV irradiation, the ASH1L-MRG15 complex adds H3K4me3 genome-wide (except active promoters) to prime chromatin for XPC relocalization from native to damaged DNA; ASH1L-MRG15 also recruits the histone chaperone FACT to DNA lesions; loss of MRG15 causes XPC misplacement and failure to deliver lesions to TFIIH.","method":"ChIP-seq, siRNA knockdown, co-immunoprecipitation, UV-irradiation, in vitro NER assay, immunofluorescence","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 2 — genome-wide ChIP-seq with Co-IP and functional NER assay, multiple orthogonal methods","pmids":["37393406"],"is_preprint":false},{"year":2013,"finding":"Drosophila Mrg15 physically interacts with the condensin Cap-H2 subunit (yeast two-hybrid); Mrg15 is required for Cap-H2-mediated chromosome unpairing in polytene chromosomes and in diploid cells, and chromatin-bound Cap-H2 levels are partially dependent on Mrg15, suggesting Mrg15 recruits Cap-H2 to chromatin for interphase chromosome compaction.","method":"Yeast two-hybrid, genetic interaction analysis, transvection assay, RNAi knockdown, chromatin fractionation","journal":"Genetics","confidence":"Medium","confidence_rationale":"Tier 2-3 — yeast two-hybrid plus genetic epistasis and chromatin fractionation; Drosophila ortholog","pmids":["23821596"],"is_preprint":false},{"year":2011,"finding":"Loss of MRG15 in neural stem/progenitor cells leads to up-regulation of p21 CDK inhibitor via p53 accumulation; p21 shRNA rescues the proliferation defect; DNA damage foci (γH2AX, 53BP1) are detectable in Mrg15-null NSCs under normal conditions, and Mrg15-null NSCs are defective in DNA damage response after ionizing radiation.","method":"Neurosphere assay, p21 shRNA rescue, immunostaining for γH2AX/53BP1, BrdU incorporation, p53 shRNA knockdown","journal":"Stem cell research","confidence":"Medium","confidence_rationale":"Tier 2-3 — shRNA rescue places MRG15 upstream of p53/p21 axis, supported by immunostaining","pmids":["21621175"],"is_preprint":false},{"year":2025,"finding":"MORF4L1 is identified as an endogenous substrate of the CRBN E3 ubiquitin ligase; CRBN promotes MORF4L1 ubiquitination and degradation under physiological conditions, further enhanced by the modulator CC-885.","method":"Proteomic analysis, co-immunoprecipitation, structural modeling, functional degradation assay","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2-3 — Co-IP with proteomic and functional degradation evidence, single lab","pmids":["39827217"],"is_preprint":false},{"year":2021,"finding":"MORF4L1 is ubiquitylated at K187 and K104 under basal conditions, and these sites show decreased ubiquitylation upon proteasome inhibition while MORF4L1 protein abundance increases ~2-fold, demonstrating that MORF4L1 protein levels are regulated by the ubiquitin-proteasome system.","method":"Large-scale ubiquitylome mass spectrometry, proteasome inhibitor treatment (MG132, bortezomib, carfilzomib), quantitative proteomics","journal":"Journal of proteomics","confidence":"Medium","confidence_rationale":"Tier 2-3 — MS-based ubiquitylome with multiple inhibitors, single lab","pmids":["33848640"],"is_preprint":false},{"year":2025,"finding":"USP53 deubiquitinase binds MORF4L1 and prevents its ubiquitination and proteasomal degradation at K249 and K227 residues; gain-of-function of USP53 stabilizes MORF4L1 and suppresses colorectal cancer cell proliferation.","method":"IP-LC/MS, ubiquitylome analysis, Co-immunoprecipitation, site-directed mutagenesis (K249, K227), gain/loss-of-function assays","journal":"Biochimica et biophysica acta. Molecular basis of disease","confidence":"Medium","confidence_rationale":"Tier 2-3 — IP-MS identifies substrate, mutagenesis validates sites, functional assays confirm effect","pmids":["41061828"],"is_preprint":false},{"year":2025,"finding":"MRG15 long isoform (MRG15L, accumulating with age) exhibits reduced affinity for histone H4 acetylation sites and weakens CDK1 regulation, causing G2/M phase arrest and cellular senescence; MuSC-specific knockout of MRG15L in mice enhances cardiac repair after ischemia-reperfusion injury.","method":"Histone peptide binding assay, protein interaction analysis, cell cycle analysis (FACS), conditional KO mouse, cardiac injury model","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 2-3 — binding assay and conditional KO with defined phenotype, single lab","pmids":["40483328"],"is_preprint":false},{"year":2025,"finding":"MRG15 forms an activator complex with TIP60, p300, and RNA Pol II at the Ccnd1 (cyclin D1) enhancer region to facilitate histone acetylation and cardiomyocyte proliferation in the neonatal heart; MRG15 knockout in cardiac progenitors impairs neonatal heart regeneration; regulatory T cells induce MRG15 expression to promote cardiomyocyte proliferation via paracrine signaling.","method":"Conditional KO mouse (Isl1-Cre, Myh6-MerCreMer), ChIP-seq, RNA-seq, Co-immunoprecipitation, AAV9-mediated overexpression, Treg depletion/adoptive transfer","journal":"Circulation","confidence":"High","confidence_rationale":"Tier 2 — genetic KO with ChIP-seq and multiple orthogonal mechanistic and functional assays","pmids":["41251000"],"is_preprint":false},{"year":2026,"finding":"MRG15 cooperates with MyoD to remodel chromatin at myogenic gene loci; MuSC-specific inducible KO shows that MRG15 is required for myogenic differentiation and muscle regeneration, with ChIP-seq revealing MRG15 modulates histone modifications at MyoD target genes.","method":"Inducible KO mouse model, RNA-seq, ChIP-seq, co-immunoprecipitation (MRG15-MyoD interaction)","journal":"Cell regeneration","confidence":"Medium","confidence_rationale":"Tier 2-3 — clean iKO with RNA-seq and ChIP-seq, single lab","pmids":["41580578"],"is_preprint":false},{"year":2025,"finding":"MRG15 promotes PCSK9 synthesis and secretion in hepatocytes, which induces macrophage M1 polarization; MRG15 knockdown in hepatocytes reduces PCSK9 secretion and attenuates macrophage activation and inflammatory response in sepsis-induced liver injury.","method":"Co-culture of hepatocytes and macrophages, MRG15 knockdown, PCSK9 ELISA, macrophage polarization assay, in vivo sepsis models (CLP, LPS)","journal":"International immunopharmacology","confidence":"Medium","confidence_rationale":"Tier 2-3 — KD with in vitro co-culture and in vivo model, mechanistic link to PCSK9, single lab","pmids":["39128417"],"is_preprint":false},{"year":2025,"finding":"MRG15 can form phase-separated liquid condensates via its intrinsically disordered region (IDR); IDR deletion abolishes condensate formation and promotes cellular senescence in human mesenchymal stem cells; MRG15 depletion diminishes chromatin binding at cell cycle and senescence genes including p53, CDKN1A, LMNB1, and CCNB1.","method":"Phase separation assay, IDR deletion/replacement, ChIP-seq, RNA-seq, senescence assays","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 2-3 — phase separation with IDR domain deletion and epigenomic readouts, single lab","pmids":["40312521"],"is_preprint":false},{"year":2025,"finding":"MORF4L1 acetylates PALB2 at lysine 628, inhibiting PALB2 ubiquitination and subsequent degradation; MORF4L1 also enhances histone H3 acetylation at K4 to facilitate DNA damage repair factor recruitment.","method":"Immunoprecipitation-mass spectrometry, Co-immunoprecipitation, acetylation site mutagenesis, ubiquitination assay","journal":"Cellular & molecular immunology","confidence":"Medium","confidence_rationale":"Tier 2-3 — IP-MS with mutagenesis and functional assays, single lab","pmids":["41188483"],"is_preprint":false}],"current_model":"MORF4L1/MRG15 is a conserved chromodomain-MRG domain protein that functions as an adapter/reader within multiple HAT (NuA4/Tip60) and HDAC (Rpd3S/Sin3S) complexes: its chromodomain reads H3K36me2/3 marks at transcribed gene bodies to direct deacetylation and splicing, it activates ASH1L H3K36 methyltransferase activity by displacing an autoinhibitory loop (or recruiting nucleosome substrate), it recruits PALB2 and the BRCA complex to H3K36me3-marked active chromatin to protect against replication-associated DNA damage, its homodimerization and stability are regulated by HDAC2-mediated deacetylation at K148 and by ubiquitin-proteasome degradation (with CRBN as E3 ligase and USP53 as deubiquitinase), and it also operates outside the nucleus at the outer mitochondrial membrane where it deacetylates TUFM to promote its ClpXP-mediated degradation, impairing mitophagy and driving NASH progression."},"narrative":{"teleology":[{"year":2001,"claim":"The first evidence that MORF4L1 operates within multiprotein complexes came from demonstrating that it binds retinoblastoma protein and PAM14 through its HLH-leucine zipper domain to relieve Rb-mediated repression of the B-myb promoter, establishing MORF4L1 as a transcriptional coregulator.","evidence":"Co-immunoprecipitation, yeast two-hybrid, and promoter-reporter assays in mammalian cells","pmids":["11500496"],"confidence":"High","gaps":["Physiological relevance of B-myb activation not tested in vivo","Stoichiometry of the Rb–MRG15–PAM14 complex unknown"]},{"year":2002,"claim":"Biochemical fractionation revealed that MORF4L1 participates in at least two functionally distinct complexes—an HAT complex containing hMOF (requiring the chromodomain) and an Rb-containing complex (requiring the leucine zipper)—and separately that MORF4L1 represses transcription through mSin3A/TLE HDAC corepressors modulated by Pf1, establishing it as a bifunctional chromatin adapter bridging acetylation and deacetylation.","evidence":"Sucrose gradient fractionation, HAT assays, Gal4-reporter assays, and domain deletion mapping","pmids":["12397079","12391155"],"confidence":"High","gaps":["How cells specify MORF4L1 partitioning between HAT and HDAC complexes was unknown","In vivo genomic targets of each complex uncharacterized"]},{"year":2005,"claim":"Mrg15 knockout mice showed embryonic lethality with reduced proliferation but not increased apoptosis, and ChIP showed MRG15 at the alpha-globin promoter during erythroid differentiation, establishing an essential developmental role and direct chromatin occupancy.","evidence":"Knockout mouse, BrdU incorporation, chromatin immunoprecipitation","pmids":["15798182"],"confidence":"High","gaps":["Molecular basis of proliferation defect (which target genes) was unresolved","Contribution of individual complexes to lethality unknown"]},{"year":2006,"claim":"Structural determination of both functional domains—the chromodomain bound to methylated H3K36 and the MRG domain bound to PAM14—revealed the molecular basis of MORF4L1's dual-reader/adapter architecture: a hydrophobic aromatic cage selectively accommodates H3K36me but not other methyl-lysine marks, while a shallow hydrophobic pocket on the MRG domain engages partner proteins.","evidence":"X-ray crystallography at 2.2 Å (chromodomain) and MRG domain, plus mutagenesis and peptide binding assays","pmids":["17135209","17008723"],"confidence":"High","gaps":["Affinity for H3K36me2 vs me3 not quantified","Whether the same molecule can simultaneously engage chromatin and partners was unknown"]},{"year":2007,"claim":"Two studies expanded MORF4L1's functional repertoire: it co-purifies with the H3K4 demethylase RBP2 and colocalizes with elongating RNA Pol II, and Mrg15-null MEFs show delayed γH2AX and 53BP1 focus formation after irradiation, linking MORF4L1 to both transcription-coupled demethylation and the DNA damage response.","evidence":"Co-IP/mass spectrometry with demethylase assay; gamma irradiation of KO MEFs with immunofluorescence","pmids":["17573780","17961556"],"confidence":"High","gaps":["Mechanism by which MORF4L1 facilitates damage signaling was unclear","Whether RBP2 interaction is direct or bridged by other subunits was not resolved"]},{"year":2009,"claim":"Direct binding of MORF4L1 to PALB2 was discovered, and disrupting this interaction elevated gene conversion and sister chromatid exchange rates, revealing that MORF4L1 constrains homologous recombination fidelity.","evidence":"Co-IP, pulldown with recombinant proteins, gene conversion and SCE assays with point mutants","pmids":["19553677"],"confidence":"High","gaps":["How MORF4L1 suppresses hyper-recombination mechanistically was not established","Whether the chromodomain was required for this function was untested"]},{"year":2010,"claim":"MORF4L1 was shown to be the chromatin anchor for the entire BRCA complex (BRCA1–PALB2–BRCA2–RAD51); its loss abolished PALB2/BRCA2/RAD51 recruitment to damage sites, reduced homology-directed repair, and caused interstrand crosslink hypersensitivity, establishing a complete pathway from histone mark reading to repair factor loading.","evidence":"Purified complex analysis, chromatin fractionation, HR reporter assay, ICL sensitivity assay, and immunofluorescence of repair foci","pmids":["20332121"],"confidence":"High","gaps":["Which histone mark was recognized at damage sites (H3K36me3 vs others) was not yet linked","Temporal ordering of MORF4L1 arrival relative to damage sensing unknown"]},{"year":2011,"claim":"Multiple studies refined the competition model for MORF4L1 complex assembly: NMR showed mSin3A and MORF4L1 compete for overlapping Pf1 binding surfaces, MORF4L1 occupied the CDK1 promoter during S phase cooperating with Tip60 for H4K12 acetylation, and loss of MRG15 in neural stem cells activated p53/p21 causing proliferation arrest.","evidence":"NMR structure of Sin3A–Pf1, ChIP at cdc2 promoter with HAT inhibitor, p21/p53 shRNA rescue in Mrg15-null NSCs","pmids":["21440557","21324423","21621175"],"confidence":"High","gaps":["Whether mutual exclusivity of Sin3A and MRG15 for Pf1 operates genome-wide was untested","Direct HAT activity of Tip60 at CDK1 promoter not reconstituted in vitro"]},{"year":2012,"claim":"Quantitative binding measurements established that MORF4L1 chromodomain binds H3K36me2/3 with weak (>100 µM) affinity, and that bivalent engagement with Pf1's PHD1 domain (reading unmodified H3K4) is required for Rpd3S/Sin3S targeting, explaining how a weak reader achieves specificity through multivalent contacts.","evidence":"ITC, peptide pulldown, domain deletion in the context of reconstituted Pf1–MRG15 complex","pmids":["22728643"],"confidence":"High","gaps":["In vivo contribution of bivalent reading not validated by ChIP of mutants","How other complex subunits contribute to chromatin affinity was unresolved"]},{"year":2014,"claim":"HDAC2-mediated deacetylation of MORF4L1 at K148 was shown to be required for homodimerization, revealing a post-translational switch that controls MORF4L1 self-assembly and potentially complex stoichiometry.","evidence":"Site-directed mutagenesis (K148R/L/Q), Co-IP of acetylation mimics, HDAC2 knockdown","pmids":["24451372"],"confidence":"High","gaps":["Functional consequence of dimerization for chromatin targeting or complex activity unknown","Whether dimerization occurs within or between complexes was unresolved"]},{"year":2016,"claim":"Conditional knockout in spermatocytes revealed that MORF4L1 reads H3K36me3 in introns and colocalizes with splicing factors PTBP1/PTBP2 to promote co-transcriptional splicing; loss caused intron retention in transition protein mRNAs and spermatogenic arrest, establishing a direct role in coupling histone marks to pre-mRNA processing.","evidence":"Conditional KO mouse, RNA-seq, ChIP, co-immunofluorescence","pmids":["27573846"],"confidence":"High","gaps":["Whether MORF4L1 directly binds PTBP1/PTBP2 or recruits them indirectly was not determined","Generality of the splicing role beyond spermatogenesis was unclear"]},{"year":2017,"claim":"Two key advances: (1) MORF4L1 was identified as a subunit of the Ash1 methyltransferase complex that stimulates H3K36 methylation and is required for Ash1 chromatin occupancy at Hox genes, and (2) ChIP-seq demonstrated that PALB2–MORF4L1 association with active genes depends on SETD2-deposited H3K36me3, completing the SETD2→H3K36me3→MRG15→PALB2 axis protecting replication through gene bodies.","evidence":"In vitro HMT assay with genetic rescue in Drosophila; ChIP-seq, camptothecin sensitivity, DNA combing in human cells","pmids":["29158494","28673974"],"confidence":"High","gaps":["Whether the Ash1–MRG15 complex uses the chromodomain for genomic targeting was not tested","Structural basis of MRG15-mediated Ash1 activation was unknown"]},{"year":2019,"claim":"Two independent crystal structures of the ASH1L–MRG15 complex resolved how MORF4L1 activates ASH1L: the MRG domain binds a conserved FxLP motif and displaces the autoinhibitory post-SET loop, opening the substrate binding pocket and inducing conformational coupling to the SAM-binding site.","evidence":"X-ray crystallography with in vitro methyltransferase assays and mutagenesis, independently replicated","pmids":["30827841","30827843"],"confidence":"High","gaps":["Whether this allosteric mechanism operates on nucleosomal substrates was not demonstrated","In vivo validation of the autoinhibitory loop displacement model was lacking"]},{"year":2020,"claim":"ChIP-seq in mouse liver revealed diurnally rhythmic MORF4L1 genomic binding at lipid synthesis genes, mediated by interaction with nuclear receptor LRH-1 rather than core clock factors, and MORF4L1 depletion impaired rhythmic Pol II recruitment and histone acetylation, revealing a metabolic regulatory function.","evidence":"ChIP-seq time-course, Co-IP, CRISPR targeting, RNA-seq","pmids":["32694659"],"confidence":"High","gaps":["Which HAT complex mediates acetylation at lipid genes was not identified","Whether LRH-1 interaction is direct or bridged was not structurally resolved"]},{"year":2021,"claim":"Structural and stability studies showed that PALB2 binds the MRG domain with nanomolar affinity at a surface overlapping other partner binding sites, confirming mutually exclusive complex formation, and ubiquitylome analysis established that MORF4L1 protein levels are controlled by ubiquitin-proteasome degradation at K187 and K104.","evidence":"X-ray crystallography with SPR; large-scale ubiquitylome MS with proteasome inhibitors","pmids":["34946951","33848640"],"confidence":"High","gaps":["Identity of the E3 ligase for basal turnover was unknown at this point","Whether ubiquitination regulates MORF4L1 complex partitioning was untested"]},{"year":2022,"claim":"MORF4L1 was discovered at the outer mitochondrial membrane where it deacetylates TUFM at K82/K91, targeting TUFM for ClpXP-mediated degradation; this impairs mitophagy and activates the NLRP3 inflammasome, driving NASH pathology—the first demonstration of a non-nuclear MORF4L1 function.","evidence":"IP-MS, Co-IP, mitochondrial fractionation, CRISPR KO, mitophagy and NLRP3 assays in NASH models","pmids":["35985547"],"confidence":"High","gaps":["Mechanism of MORF4L1 targeting to mitochondria is unknown","Whether MORF4L1 possesses intrinsic deacetylase activity or recruits an HDAC at mitochondria was not distinguished"]},{"year":2023,"claim":"Two studies revised the ASH1L activation model and expanded DNA repair roles: NMR showed MORF4L1 does not alter ASH1L autoinhibitory loop conformation in solution but instead functions as a nucleosome-recruiting adapter via its chromodomain; separately, the ASH1L–MRG15 complex was found to deposit H3K4me3 genome-wide after UV damage to relocalize XPC and recruit the FACT chaperone, establishing a role in nucleotide excision repair.","evidence":"In vitro HMT assay with nucleosomes and NMR; ChIP-seq after UV irradiation with NER reconstitution","pmids":["37527654","37393406"],"confidence":"High","gaps":["Whether the nucleosome-recruiting and allosteric mechanisms are mutually exclusive or additive in vivo is unresolved","How ASH1L–MRG15 switches from H3K36 to H3K4 methylation specificity upon UV damage is unexplained"]},{"year":2025,"claim":"Multiple 2025 studies expanded the regulatory and functional landscape: CRBN was identified as an E3 ligase for MORF4L1, USP53 as a stabilizing deubiquitinase, phase separation via the IDR was linked to senescence suppression, a long isoform (MRG15L) was shown to weaken CDK1 regulation causing senescence, and MORF4L1 was found to promote cardiomyocyte proliferation at the Ccnd1 enhancer with Tip60/p300 and to cooperate with MyoD for myogenic differentiation.","evidence":"Proteomic/Co-IP degradation assays; phase separation/ChIP-seq; conditional KO mice in cardiac and muscle stem cells; isoform-specific binding and FACS analyses","pmids":["39827217","41061828","40312521","40483328","41251000","41580578"],"confidence":"Medium","gaps":["Interplay between CRBN and USP53 in setting MORF4L1 levels is unexplored","Whether phase separation is required for complex assembly in vivo needs validation","MRG15L isoform mechanism for altered histone binding is structurally uncharacterized"]},{"year":null,"claim":"Key unresolved questions include: how MORF4L1 is directed to the outer mitochondrial membrane and whether it possesses intrinsic deacetylase activity; how cells partition a single MORF4L1 pool among mutually exclusive complexes (NuA4, Sin3S, ASH1L, PALB2); whether phase separation contributes to complex specificity in vivo; and how the ASH1L–MRG15 complex switches histone substrate specificity from H3K36 to H3K4 upon DNA damage.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural or biochemical mechanism for mitochondrial targeting","No quantitative model of competitive complex partitioning","Switch mechanism for ASH1L substrate specificity under damage conditions unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0042393","term_label":"histone binding","supporting_discovery_ids":[0,12,16,22]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[2,3,8,14,17]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[1,10,19,30]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[14,17,22]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[1,2,4,6,10,16,19]},{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[0,15,16,24]},{"term_id":"GO:0005739","term_label":"mitochondrion","supporting_discovery_ids":[21]}],"pathway":[{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[0,2,3,10,12,14,17]},{"term_id":"R-HSA-73894","term_label":"DNA Repair","supporting_discovery_ids":[7,8,9,15,23]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[1,6,10,19,30]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[4,10,25,29]},{"term_id":"R-HSA-8953854","term_label":"Metabolism of RNA","supporting_discovery_ids":[16]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[21]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[4,30,31]}],"complexes":["NuA4/Tip60 HAT complex","Sin3A/Rpd3S HDAC complex","ASH1L methyltransferase complex","BRCA/PALB2 repair complex"],"partners":["PALB2","ASH1L","MRGBP","PHF12","SIN3A","KAT8","KAT5","TUFM"],"other_free_text":[]},"mechanistic_narrative":"MORF4L1 (MRG15) is a conserved chromatin adapter protein whose N-terminal chromodomain selectively reads H3K36me2/3 marks and whose C-terminal MRG domain mediates mutually exclusive interactions with diverse effector complexes, thereby coupling histone modification state to transcriptional regulation, DNA repair, splicing, and chromosome organization. Through its chromodomain, MORF4L1 targets the NuA4/Tip60 histone acetyltransferase complex and the Rpd3S/Sin3A histone deacetylase complex to transcribed gene bodies, while its MRG domain activates the ASH1L H3K36 methyltransferase by displacing the autoinhibitory loop and recruiting nucleosome substrates [PMID:30827841, PMID:37527654]. MORF4L1 recruits PALB2 and the BRCA1–BRCA2–RAD51 complex to H3K36me3-marked active chromatin to protect replication forks and facilitate homology-directed repair and nucleotide excision repair [PMID:20332121, PMID:28673974, PMID:37393406]. MORF4L1 is essential for embryonic viability and cell proliferation, regulates pre-mRNA splicing during spermatogenesis, controls diurnal lipid gene expression via LRH-1, and also localizes to the outer mitochondrial membrane where it promotes TUFM deacetylation and degradation, impairing mitophagy in NASH [PMID:15798182, PMID:27573846, PMID:32694659, PMID:35985547]."},"prefetch_data":{"uniprot":{"accession":"Q9UBU8","full_name":"Mortality factor 4-like protein 1","aliases":["MORF-related gene 15 protein","MRG15","Protein MSL3-1","Transcription factor-like protein MRG15"],"length_aa":362,"mass_kda":41.5,"function":"Component of the NuA4 histone acetyltransferase (HAT) complex which is involved in transcriptional activation of select genes principally by acetylation of nucleosomal histones H4 and H2A. This modification may both alter nucleosome - DNA interactions and promote interaction of the modified histones with other proteins which positively regulate transcription. This complex may be required for the activation of transcriptional programs associated with oncogene and proto-oncogene mediated growth induction, tumor suppressor mediated growth arrest and replicative senescence, apoptosis, and DNA repair. The NuA4 complex ATPase and helicase activities seem to be, at least in part, contributed by the association of RUVBL1 and RUVBL2 with EP400. NuA4 may also play a direct role in DNA repair when directly recruited to sites of DNA damage. As part of the SIN3B complex represses transcription and counteracts the histone acetyltransferase activity of EP300 through the recognition H3K27ac marks by PHF12 and the activity of the histone deacetylase HDAC2 (PubMed:12391155, PubMed:14966270, PubMed:37137925). SIN3B complex is recruited downstream of the constitutively active genes transcriptional start sites through interaction with histones and mitigates histone acetylation and RNA polymerase II progression within transcribed regions contributing to the regulation of transcription (PubMed:21041482). Required for homologous recombination repair (HRR) and resistance to mitomycin C (MMC). Involved in the localization of PALB2, BRCA2 and RAD51, but not BRCA1, to DNA-damage foci","subcellular_location":"Nucleus","url":"https://www.uniprot.org/uniprotkb/Q9UBU8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MORF4L1","classification":"Not Classified","n_dependent_lines":99,"n_total_lines":1208,"dependency_fraction":0.08195364238410596},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"TRRAP","stoichiometry":10.0},{"gene":"H2AFZ","stoichiometry":0.2},{"gene":"HSPA4","stoichiometry":0.2},{"gene":"SNRPC","stoichiometry":0.2},{"gene":"SPTLC1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/MORF4L1","total_profiled":1310},"omim":[{"mim_id":"616905","title":"MORF4 FAMILY-ASSOCIATED PROTEIN 1; MRFAP1","url":"https://www.omim.org/entry/616905"},{"mim_id":"614041","title":"RB TRANSCRIPTIONAL COREPRESSOR 1; RB1","url":"https://www.omim.org/entry/614041"},{"mim_id":"611157","title":"MRG/MORF4L-BINDING PROTEIN; MRGBP","url":"https://www.omim.org/entry/611157"},{"mim_id":"607303","title":"MORTALITY FACTOR 4-LIKE PROTEIN 1; MORF4L1","url":"https://www.omim.org/entry/607303"},{"mim_id":"601409","title":"LYSINE ACETYLTRANSFERASE 5; KAT5","url":"https://www.omim.org/entry/601409"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Nuclear speckles","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/MORF4L1"},"hgnc":{"alias_symbol":["MRG15","MORFRG15","HsT17725","Eaf3","MEAF3"],"prev_symbol":[]},"alphafold":{"accession":"Q9UBU8","domains":[{"cath_id":"2.30.30.140","chopping":"7-49_91-123","consensus_level":"medium","plddt":83.6849,"start":7,"end":123},{"cath_id":"1.10.274.30","chopping":"192-358","consensus_level":"high","plddt":90.2125,"start":192,"end":358}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UBU8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UBU8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UBU8-F1-predicted_aligned_error_v6.png","plddt_mean":73.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MORF4L1","jax_strain_url":"https://www.jax.org/strain/search?query=MORF4L1"},"sequence":{"accession":"Q9UBU8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9UBU8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9UBU8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UBU8"}},"corpus_meta":[{"pmid":"16364921","id":"PMC_16364921","title":"Eaf3 chromodomain interaction with methylated H3-K36 links histone deacetylation to Pol II elongation.","date":"2005","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/16364921","citation_count":427,"is_preprint":false},{"pmid":"17135209","id":"PMC_17135209","title":"Structure of human MRG15 chromo domain and its binding to Lys36-methylated histone H3.","date":"2006","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/17135209","citation_count":123,"is_preprint":false},{"pmid":"12391155","id":"PMC_12391155","title":"Role for the mortality factors MORF4, MRGX, and MRG15 in transcriptional repression via associations with Pf1, mSin3A, and Transducin-Like Enhancer of Split.","date":"2002","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/12391155","citation_count":83,"is_preprint":false},{"pmid":"17573780","id":"PMC_17573780","title":"RBP2 is an MRG15 complex component and down-regulates intragenic histone H3 lysine 4 methylation.","date":"2007","source":"Genes to cells : devoted to molecular & cellular mechanisms","url":"https://pubmed.ncbi.nlm.nih.gov/17573780","citation_count":81,"is_preprint":false},{"pmid":"12397079","id":"PMC_12397079","title":"MRG15, a novel chromodomain protein, is present in two distinct multiprotein complexes involved in transcriptional activation.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12397079","citation_count":73,"is_preprint":false},{"pmid":"18818090","id":"PMC_18818090","title":"Structural basis for the recognition of methylated histone H3K36 by the Eaf3 subunit of histone deacetylase complex Rpd3S.","date":"2008","source":"Structure (London, England : 1993)","url":"https://pubmed.ncbi.nlm.nih.gov/18818090","citation_count":73,"is_preprint":false},{"pmid":"15798182","id":"PMC_15798182","title":"MRG15 regulates embryonic development and cell proliferation.","date":"2005","source":"Molecular and cellular 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D","url":"https://pubmed.ncbi.nlm.nih.gov/32808584","citation_count":7,"is_preprint":false},{"pmid":"23733253","id":"PMC_23733253","title":"Alternative splicing of the chromodomain protein Morf4l1 pre-mRNA has implications on cell differentiation in the developing chicken retina.","date":"2013","source":"Journal of molecular neuroscience : MN","url":"https://pubmed.ncbi.nlm.nih.gov/23733253","citation_count":6,"is_preprint":false},{"pmid":"35860629","id":"PMC_35860629","title":"ADSCs Promote Tenocyte Proliferation by Reducing the Methylation Level of lncRNA Morf4l1 in Tendon Injury.","date":"2022","source":"Frontiers in chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/35860629","citation_count":6,"is_preprint":false},{"pmid":"39487311","id":"PMC_39487311","title":"MRG15 promotes cell apoptosis through inhibition of mitophagy in hyperlipidemic acute pancreatitis.","date":"2024","source":"Apoptosis : an international journal on programmed cell death","url":"https://pubmed.ncbi.nlm.nih.gov/39487311","citation_count":6,"is_preprint":false},{"pmid":"38191914","id":"PMC_38191914","title":"Structural and functional insights into the epigenetic regulator MRG15.","date":"2024","source":"Acta pharmacologica Sinica","url":"https://pubmed.ncbi.nlm.nih.gov/38191914","citation_count":5,"is_preprint":false},{"pmid":"20844547","id":"PMC_20844547","title":"Mutation analysis of the gene encoding the PALB2-binding protein MRG15 in BRCA1/2-negative breast cancer families.","date":"2010","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/20844547","citation_count":5,"is_preprint":false},{"pmid":"39827217","id":"PMC_39827217","title":"Identification of MORF4L1 as an endogenous substrate of CRBN and its potential role as a therapeutic target in cancer.","date":"2025","source":"Scientific 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disease","url":"https://pubmed.ncbi.nlm.nih.gov/37504562","citation_count":3,"is_preprint":false},{"pmid":"38521716","id":"PMC_38521716","title":"Emerging roles of MRG15 in liver metabolic diseases.","date":"2024","source":"Trends in molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/38521716","citation_count":2,"is_preprint":false},{"pmid":"39757177","id":"PMC_39757177","title":"Predicting hepatocellular carcinoma outcomes and immune therapy response with ATP-dependent chromatin remodeling-related genes, highlighting MORF4L1 as a promising target.","date":"2025","source":"Cancer cell international","url":"https://pubmed.ncbi.nlm.nih.gov/39757177","citation_count":2,"is_preprint":false},{"pmid":"41188483","id":"PMC_41188483","title":"Targeting MORF4L1-mediated DNA repair potentiates RT-induced antitumor immunity via cGAS-STING activation in hepatocellular carcinoma.","date":"2025","source":"Cellular & molecular 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Coupled with Machine Learning Uncovers MORF4L1 as a Critical Epigenetic Mediator of Radiotherapy Resistance in Colorectal Cancer Liver Metastasis.","date":"2026","source":"Biomedicines","url":"https://pubmed.ncbi.nlm.nih.gov/41751172","citation_count":0,"is_preprint":false},{"pmid":"41061828","id":"PMC_41061828","title":"Deubiquitinase USP53 suppressed tumorigenesis of colorectal cancer cells by mediating deubiquitination of MORF4L1.","date":"2025","source":"Biochimica et biophysica acta. 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histone acetyltransferase activity co-purifies with MRG15 and is lost upon chromodomain deletion.\",\n      \"method\": \"Sucrose gradient fractionation, deletion mutant analysis, histone acetyltransferase activity assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — biochemical fractionation with domain mapping and enzymatic assay\",\n      \"pmids\": [\"12397079\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"MRG15, MRGX, and MORF4 repress transcription through direct association with mSin3A and TLE (Transducin-Like Enhancer of Split) histone deacetylase-containing corepressors; MRG15 uniquely interacts with Pf1, which reduces MRG15-mediated repression through an MRG15/Pf1/mSin3A complex.\",\n      \"method\": \"Gal4-luciferase reporter assay, Co-immunoprecipitation, domain mapping, dominant-negative TLE\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods including Co-IP, reporter assay, and dominant-negative genetics\",\n      \"pmids\": [\"12391155\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"MRG15 knockout mice display embryonic lethality with developmental delay, reduced cell proliferation in multiple tissues without increased apoptosis, and MRG15 is recruited to the alpha-globin promoter during erythroid differentiation as shown by chromatin immunoprecipitation.\",\n      \"method\": \"Knockout mouse generation, BrdU proliferation assay, chromatin immunoprecipitation (ChIP)\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with defined cellular phenotype and direct ChIP localization\",\n      \"pmids\": [\"15798182\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Crystal structure of the MRG domain of MRG15 reveals a predominantly alpha-helical three-layer sandwich topology; structure-based mutagenesis identified Ile160, Leu168, Val169, Trp172, Tyr235, Val268, and Arg269 as forming a shallow hydrophobic pocket mediating interaction with the N-terminal 50 residues of PAM14.\",\n      \"method\": \"X-ray crystallography, site-directed mutagenesis, yeast two-hybrid, in vitro binding assay\",\n      \"journal\": \"Protein science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure with mutagenesis and functional binding validation\",\n      \"pmids\": [\"17008723\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"MRG15 complex contains RBP2 (a JmjC domain H3K4 demethylase); RBP2 associated with MRG15 removes H3K4 methylation within transcribed regions in vivo, and MRG15 localizes to nuclear subdomains enriched for Ser2-phosphorylated RNA Pol II.\",\n      \"method\": \"Co-immunoprecipitation, mass spectrometry, in vitro demethylase assay, RBP2 knockdown, nuclear fractionation/immunostaining\",\n      \"journal\": \"Genes to cells\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — in vitro enzymatic assay + reciprocal Co-IP + KD with epigenetic readout\",\n      \"pmids\": [\"17573780\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"MRG15 directly binds PALB2 via an evolutionarily conserved region; disruption of this interaction elevates gene conversion rates and sister chromatid exchange frequencies, indicating MRG15 suppresses hyper-recombination during homologous recombination repair.\",\n      \"method\": \"Co-immunoprecipitation, pulldown, gene conversion assay, SCE assay, point-mutation of binding interface\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct binding identified with functional genetic consequence in two orthogonal assays\",\n      \"pmids\": [\"19553677\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"MRG15 directly binds PALB2 and mediates the association of the entire BRCA complex (BRCA1, PALB2, BRCA2, RAD51) with chromatin; MRG15-deficient cells show reduced homology-directed DNA repair, hypersensitivity to interstrand crosslinking agents, and impaired recruitment of PALB2, BRCA2, and RAD51 to DNA damage sites.\",\n      \"method\": \"Purified protein complex analysis, Co-immunoprecipitation, homology-directed repair assay, ICL sensitivity assay, immunofluorescence of repair foci, chromatin fractionation\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods with clean KD and defined DNA repair phenotypes\",\n      \"pmids\": [\"20332121\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Mrg15-null and heterozygous mouse embryonic fibroblasts exhibit delayed formation of phosphorylated H2AX and 53BP1 foci and impaired DNA repair after gamma irradiation, establishing MRG15 as required for efficient DNA damage response.\",\n      \"method\": \"Gamma irradiation of KO MEFs, immunofluorescence for γH2AX and 53BP1 foci, cell growth assay\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with defined damage-response phenotype, single lab\",\n      \"pmids\": [\"17961556\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"MRG15 occupies the cdc2 (CDK1) promoter during S phase entry and cooperates with Tip60 HAT to acetylate histone H4 (specifically H4K12) at this promoter, activating cdc2 transcription; knockdown of MRG15 reduces cdc2 promoter activity.\",\n      \"method\": \"Chromatin immunoprecipitation (ChIP), promoter-reporter assay, HAT inhibitor treatment, co-transfection\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — ChIP with functional reporter and pharmacological evidence, single lab\",\n      \"pmids\": [\"21324423\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"The mSin3A PAH2 domain interacts with the Pf1 SID1 motif in a manner similar to Mad1/Mxd1; MRG15 competes with mSin3A for binding to Pf1, implying mutual exclusivity of two subunits within the Rpd3S/Sin3S complex for Pf1.\",\n      \"method\": \"NMR solution structure, pulldown assay, competitive binding assay\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — NMR structure with functional competition binding assays\",\n      \"pmids\": [\"21440557\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"MRG15 chromodomain binds H3K36me2/3 with >100 µM affinity and Pf1 PHD1 binds unmodified H3K4 with similarly low affinity; both domains are required together for bivalent (non-cooperative) targeting of the Rpd3S/Sin3S complex to chromatin; Pf1 PHD1 also engages the MRG15 MRG domain.\",\n      \"method\": \"In vitro peptide binding assay, isothermal titration calorimetry, pulldown, domain deletion analysis\",\n      \"journal\": \"Journal of molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — quantitative binding measurements with domain mutagenesis, multiple orthogonal assays\",\n      \"pmids\": [\"22728643\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"HDAC2 deacetylates MORF4L1 at Lys-148, and this deacetylation is required for MORF4L1 homodimerization; acetylation mimics (K148L, K148Q) abolish self-assembly, while Lys-to-Arg substitution (mimicking deacetylation) promotes it; HDAC2 knockdown reduces MORF4L1 homodimerization.\",\n      \"method\": \"Co-immunoprecipitation, site-directed mutagenesis (K148R, K148L, K148Q), HDAC2 knockdown\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis of modification site with KD validation, multiple mutants\",\n      \"pmids\": [\"24451372\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"MRG15 (Mrg15 in Drosophila) is a subunit of the Ash1 histone methyltransferase complex that stimulates Ash1 H3K36 methyltransferase activity in vitro; Mrg15 is recruited by Ash1 to common genomic targets and reinforces Ash1 chromatin association; an Ash1 point mutation (R1288A) that reduces Mrg15 interaction causes homeotic transformations partially rescued by Mrg15-Nurf55 fusion.\",\n      \"method\": \"In vitro methyltransferase assay, ChIP, genetic knock-in, co-immunoprecipitation, rescue experiment\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — in vitro enzymatic assay + genetic epistasis + ChIP + multiple orthogonal methods\",\n      \"pmids\": [\"29158494\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"PALB2 associates with active genes through MRG15, which recognizes H3K36me3 deposited by SETD2; PALB2-MRG15 binding-defective missense mutations increase sensitivity to camptothecin and elevate DNA stress in gene bodies during replication, establishing a SETD2/H3K36me3/MRG15/PALB2 axis that protects active genes.\",\n      \"method\": \"ChIP-seq, missense mutation analysis, camptothecin sensitivity assay, metaphase chromosome analysis, DNA combing\",\n      \"journal\": \"Proceedings of the National Academy of Sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genome-wide ChIP-seq with functional mutations and multiple phenotypic readouts\",\n      \"pmids\": [\"28673974\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"MRG15 is required for pre-mRNA splicing during spermatogenesis; it binds H3K36me3 in introns of transcriptionally active genes and colocalizes with splicing factors PTBP1 and PTBP2 at H3K36me3 sites in round spermatids; conditional KO causes intron retention in transition protein mRNAs and spermatogenic arrest.\",\n      \"method\": \"Conditional KO mouse, RNA-seq, ChIP, co-immunofluorescence of splicing factors\",\n      \"journal\": \"Proceedings of the National Academy of Sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean conditional KO with RNA-seq, ChIP, and colocalization\",\n      \"pmids\": [\"27573846\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Crystal structure of human ASH1L tandem MID-SET domains in complex with MRG15 MRG domain reveals that MRG15 binds a conserved FxLP motif N-terminal to the ASH1L SET domain and displaces the autoinhibitory post-SET loop to open the substrate binding pocket, activating H3K36 methyltransferase activity.\",\n      \"method\": \"X-ray crystallography, in vitro methyltransferase assay, mutagenesis\",\n      \"journal\": \"Structure\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure with enzymatic activity and mutagenesis, replicated by two independent groups same year\",\n      \"pmids\": [\"30827841\", \"30827843\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Crystal structure of Ash1L MID-SET domains bound to MRG15 MRG domain shows that MRG15 binding induces subtle structural changes in the SAM-binding pocket of ASH1L via a conserved interaction segment, implicating conformational coupling between SAM and substrate binding sites as the activation mechanism.\",\n      \"method\": \"X-ray crystallography, in vitro methyltransferase assay\",\n      \"journal\": \"Structure\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure with functional validation, independent replication of Ash1L-MRG15 structure\",\n      \"pmids\": [\"30827843\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"MRG15 genomic recruitment shows significant diurnal rhythm in mouse liver and activates lipid synthesis genes; MRG15 interacts with nuclear receptor LRH-1 (not core clock proteins) and is recruited to lipid gene loci via LRH-1; MRG15 depletion impairs rhythmic Pol II recruitment and histone acetylation at lipid genes.\",\n      \"method\": \"ChIP-seq, Co-immunoprecipitation, CRISPR targeting, RNA-seq, luciferase reporter\",\n      \"journal\": \"Nature metabolism\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — ChIP-seq with Co-IP and CRISPR KO, multiple phenotypic readouts\",\n      \"pmids\": [\"32694659\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Crystal structure of the MRG15 MRG domain bound to PALB2 peptide shows PALB2 interacts with an extended surface of MRG15 with nanomolar affinity; this binding region overlaps with sites for other MRG15 partners, indicating mutually exclusive binding; breast cancer-derived PALB2 mutations cause only minor affinity reduction.\",\n      \"method\": \"X-ray crystallography, surface plasmon resonance/binding affinity measurement, PALB2 variant analysis\",\n      \"journal\": \"Genes\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure with quantitative binding measurements\",\n      \"pmids\": [\"34946951\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"MRG15 associates with the outer mitochondrial membrane and interacts with and deacetylates TUFM at K82 and K91; deacetylated TUFM is targeted for degradation by the mitochondrial ClpXP protease, resulting in impaired mitophagy, increased oxidative stress, and NLRP3 inflammasome activation in NASH; inflammatory cytokines increase MRG15 acetylation to stabilize MRG15 in this context.\",\n      \"method\": \"Immunoprecipitation-mass spectrometry, co-immunoprecipitation, CRISPR targeting, mitochondrial fractionation, mitophagy assay, NLRP3 activation assay\",\n      \"journal\": \"Journal of hepatology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — IP-MS with orthogonal Co-IP, CRISPR KO, and multiple mechanistic readouts in vivo and in vitro\",\n      \"pmids\": [\"35985547\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"MRG15, once activating ASH1L, recruits the ASH1L-MRG15 complex to nucleosome substrates via the MRG15 chromodomain; full-length MRG15 but not the MRG domain alone enhances ASH1L SET domain activity; MRG15 does not alter the conformation of the ASH1L autoinhibitory loop or SAM binding site in solution, suggesting MRG15 functions as a nucleosome-recruiting adapter rather than purely an allosteric activator.\",\n      \"method\": \"In vitro methyltransferase assay with nucleosomes, NMR, pulldown, chromodomain binding assay\",\n      \"journal\": \"Structure\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstituted enzymatic assay with NMR structural analysis and domain dissection\",\n      \"pmids\": [\"37527654\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Upon UV irradiation, the ASH1L-MRG15 complex adds H3K4me3 genome-wide (except active promoters) to prime chromatin for XPC relocalization from native to damaged DNA; ASH1L-MRG15 also recruits the histone chaperone FACT to DNA lesions; loss of MRG15 causes XPC misplacement and failure to deliver lesions to TFIIH.\",\n      \"method\": \"ChIP-seq, siRNA knockdown, co-immunoprecipitation, UV-irradiation, in vitro NER assay, immunofluorescence\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genome-wide ChIP-seq with Co-IP and functional NER assay, multiple orthogonal methods\",\n      \"pmids\": [\"37393406\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Drosophila Mrg15 physically interacts with the condensin Cap-H2 subunit (yeast two-hybrid); Mrg15 is required for Cap-H2-mediated chromosome unpairing in polytene chromosomes and in diploid cells, and chromatin-bound Cap-H2 levels are partially dependent on Mrg15, suggesting Mrg15 recruits Cap-H2 to chromatin for interphase chromosome compaction.\",\n      \"method\": \"Yeast two-hybrid, genetic interaction analysis, transvection assay, RNAi knockdown, chromatin fractionation\",\n      \"journal\": \"Genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — yeast two-hybrid plus genetic epistasis and chromatin fractionation; Drosophila ortholog\",\n      \"pmids\": [\"23821596\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Loss of MRG15 in neural stem/progenitor cells leads to up-regulation of p21 CDK inhibitor via p53 accumulation; p21 shRNA rescues the proliferation defect; DNA damage foci (γH2AX, 53BP1) are detectable in Mrg15-null NSCs under normal conditions, and Mrg15-null NSCs are defective in DNA damage response after ionizing radiation.\",\n      \"method\": \"Neurosphere assay, p21 shRNA rescue, immunostaining for γH2AX/53BP1, BrdU incorporation, p53 shRNA knockdown\",\n      \"journal\": \"Stem cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — shRNA rescue places MRG15 upstream of p53/p21 axis, supported by immunostaining\",\n      \"pmids\": [\"21621175\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MORF4L1 is identified as an endogenous substrate of the CRBN E3 ubiquitin ligase; CRBN promotes MORF4L1 ubiquitination and degradation under physiological conditions, further enhanced by the modulator CC-885.\",\n      \"method\": \"Proteomic analysis, co-immunoprecipitation, structural modeling, functional degradation assay\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — Co-IP with proteomic and functional degradation evidence, single lab\",\n      \"pmids\": [\"39827217\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MORF4L1 is ubiquitylated at K187 and K104 under basal conditions, and these sites show decreased ubiquitylation upon proteasome inhibition while MORF4L1 protein abundance increases ~2-fold, demonstrating that MORF4L1 protein levels are regulated by the ubiquitin-proteasome system.\",\n      \"method\": \"Large-scale ubiquitylome mass spectrometry, proteasome inhibitor treatment (MG132, bortezomib, carfilzomib), quantitative proteomics\",\n      \"journal\": \"Journal of proteomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — MS-based ubiquitylome with multiple inhibitors, single lab\",\n      \"pmids\": [\"33848640\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"USP53 deubiquitinase binds MORF4L1 and prevents its ubiquitination and proteasomal degradation at K249 and K227 residues; gain-of-function of USP53 stabilizes MORF4L1 and suppresses colorectal cancer cell proliferation.\",\n      \"method\": \"IP-LC/MS, ubiquitylome analysis, Co-immunoprecipitation, site-directed mutagenesis (K249, K227), gain/loss-of-function assays\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular basis of disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — IP-MS identifies substrate, mutagenesis validates sites, functional assays confirm effect\",\n      \"pmids\": [\"41061828\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MRG15 long isoform (MRG15L, accumulating with age) exhibits reduced affinity for histone H4 acetylation sites and weakens CDK1 regulation, causing G2/M phase arrest and cellular senescence; MuSC-specific knockout of MRG15L in mice enhances cardiac repair after ischemia-reperfusion injury.\",\n      \"method\": \"Histone peptide binding assay, protein interaction analysis, cell cycle analysis (FACS), conditional KO mouse, cardiac injury model\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — binding assay and conditional KO with defined phenotype, single lab\",\n      \"pmids\": [\"40483328\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MRG15 forms an activator complex with TIP60, p300, and RNA Pol II at the Ccnd1 (cyclin D1) enhancer region to facilitate histone acetylation and cardiomyocyte proliferation in the neonatal heart; MRG15 knockout in cardiac progenitors impairs neonatal heart regeneration; regulatory T cells induce MRG15 expression to promote cardiomyocyte proliferation via paracrine signaling.\",\n      \"method\": \"Conditional KO mouse (Isl1-Cre, Myh6-MerCreMer), ChIP-seq, RNA-seq, Co-immunoprecipitation, AAV9-mediated overexpression, Treg depletion/adoptive transfer\",\n      \"journal\": \"Circulation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with ChIP-seq and multiple orthogonal mechanistic and functional assays\",\n      \"pmids\": [\"41251000\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"MRG15 cooperates with MyoD to remodel chromatin at myogenic gene loci; MuSC-specific inducible KO shows that MRG15 is required for myogenic differentiation and muscle regeneration, with ChIP-seq revealing MRG15 modulates histone modifications at MyoD target genes.\",\n      \"method\": \"Inducible KO mouse model, RNA-seq, ChIP-seq, co-immunoprecipitation (MRG15-MyoD interaction)\",\n      \"journal\": \"Cell regeneration\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — clean iKO with RNA-seq and ChIP-seq, single lab\",\n      \"pmids\": [\"41580578\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MRG15 promotes PCSK9 synthesis and secretion in hepatocytes, which induces macrophage M1 polarization; MRG15 knockdown in hepatocytes reduces PCSK9 secretion and attenuates macrophage activation and inflammatory response in sepsis-induced liver injury.\",\n      \"method\": \"Co-culture of hepatocytes and macrophages, MRG15 knockdown, PCSK9 ELISA, macrophage polarization assay, in vivo sepsis models (CLP, LPS)\",\n      \"journal\": \"International immunopharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — KD with in vitro co-culture and in vivo model, mechanistic link to PCSK9, single lab\",\n      \"pmids\": [\"39128417\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MRG15 can form phase-separated liquid condensates via its intrinsically disordered region (IDR); IDR deletion abolishes condensate formation and promotes cellular senescence in human mesenchymal stem cells; MRG15 depletion diminishes chromatin binding at cell cycle and senescence genes including p53, CDKN1A, LMNB1, and CCNB1.\",\n      \"method\": \"Phase separation assay, IDR deletion/replacement, ChIP-seq, RNA-seq, senescence assays\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — phase separation with IDR domain deletion and epigenomic readouts, single lab\",\n      \"pmids\": [\"40312521\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MORF4L1 acetylates PALB2 at lysine 628, inhibiting PALB2 ubiquitination and subsequent degradation; MORF4L1 also enhances histone H3 acetylation at K4 to facilitate DNA damage repair factor recruitment.\",\n      \"method\": \"Immunoprecipitation-mass spectrometry, Co-immunoprecipitation, acetylation site mutagenesis, ubiquitination assay\",\n      \"journal\": \"Cellular & molecular immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — IP-MS with mutagenesis and functional assays, single lab\",\n      \"pmids\": [\"41188483\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MORF4L1/MRG15 is a conserved chromodomain-MRG domain protein that functions as an adapter/reader within multiple HAT (NuA4/Tip60) and HDAC (Rpd3S/Sin3S) complexes: its chromodomain reads H3K36me2/3 marks at transcribed gene bodies to direct deacetylation and splicing, it activates ASH1L H3K36 methyltransferase activity by displacing an autoinhibitory loop (or recruiting nucleosome substrate), it recruits PALB2 and the BRCA complex to H3K36me3-marked active chromatin to protect against replication-associated DNA damage, its homodimerization and stability are regulated by HDAC2-mediated deacetylation at K148 and by ubiquitin-proteasome degradation (with CRBN as E3 ligase and USP53 as deubiquitinase), and it also operates outside the nucleus at the outer mitochondrial membrane where it deacetylates TUFM to promote its ClpXP-mediated degradation, impairing mitophagy and driving NASH progression.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"MORF4L1 (MRG15) is a conserved chromatin adapter protein whose N-terminal chromodomain selectively reads H3K36me2/3 marks and whose C-terminal MRG domain mediates mutually exclusive interactions with diverse effector complexes, thereby coupling histone modification state to transcriptional regulation, DNA repair, splicing, and chromosome organization. Through its chromodomain, MORF4L1 targets the NuA4/Tip60 histone acetyltransferase complex and the Rpd3S/Sin3A histone deacetylase complex to transcribed gene bodies, while its MRG domain activates the ASH1L H3K36 methyltransferase by displacing the autoinhibitory loop and recruiting nucleosome substrates [PMID:30827841, PMID:37527654]. MORF4L1 recruits PALB2 and the BRCA1–BRCA2–RAD51 complex to H3K36me3-marked active chromatin to protect replication forks and facilitate homology-directed repair and nucleotide excision repair [PMID:20332121, PMID:28673974, PMID:37393406]. MORF4L1 is essential for embryonic viability and cell proliferation, regulates pre-mRNA splicing during spermatogenesis, controls diurnal lipid gene expression via LRH-1, and also localizes to the outer mitochondrial membrane where it promotes TUFM deacetylation and degradation, impairing mitophagy in NASH [PMID:15798182, PMID:27573846, PMID:32694659, PMID:35985547].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"The first evidence that MORF4L1 operates within multiprotein complexes came from demonstrating that it binds retinoblastoma protein and PAM14 through its HLH-leucine zipper domain to relieve Rb-mediated repression of the B-myb promoter, establishing MORF4L1 as a transcriptional coregulator.\",\n      \"evidence\": \"Co-immunoprecipitation, yeast two-hybrid, and promoter-reporter assays in mammalian cells\",\n      \"pmids\": [\"11500496\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological relevance of B-myb activation not tested in vivo\", \"Stoichiometry of the Rb–MRG15–PAM14 complex unknown\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Biochemical fractionation revealed that MORF4L1 participates in at least two functionally distinct complexes—an HAT complex containing hMOF (requiring the chromodomain) and an Rb-containing complex (requiring the leucine zipper)—and separately that MORF4L1 represses transcription through mSin3A/TLE HDAC corepressors modulated by Pf1, establishing it as a bifunctional chromatin adapter bridging acetylation and deacetylation.\",\n      \"evidence\": \"Sucrose gradient fractionation, HAT assays, Gal4-reporter assays, and domain deletion mapping\",\n      \"pmids\": [\"12397079\", \"12391155\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How cells specify MORF4L1 partitioning between HAT and HDAC complexes was unknown\", \"In vivo genomic targets of each complex uncharacterized\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Mrg15 knockout mice showed embryonic lethality with reduced proliferation but not increased apoptosis, and ChIP showed MRG15 at the alpha-globin promoter during erythroid differentiation, establishing an essential developmental role and direct chromatin occupancy.\",\n      \"evidence\": \"Knockout mouse, BrdU incorporation, chromatin immunoprecipitation\",\n      \"pmids\": [\"15798182\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of proliferation defect (which target genes) was unresolved\", \"Contribution of individual complexes to lethality unknown\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Structural determination of both functional domains—the chromodomain bound to methylated H3K36 and the MRG domain bound to PAM14—revealed the molecular basis of MORF4L1's dual-reader/adapter architecture: a hydrophobic aromatic cage selectively accommodates H3K36me but not other methyl-lysine marks, while a shallow hydrophobic pocket on the MRG domain engages partner proteins.\",\n      \"evidence\": \"X-ray crystallography at 2.2 Å (chromodomain) and MRG domain, plus mutagenesis and peptide binding assays\",\n      \"pmids\": [\"17135209\", \"17008723\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Affinity for H3K36me2 vs me3 not quantified\", \"Whether the same molecule can simultaneously engage chromatin and partners was unknown\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Two studies expanded MORF4L1's functional repertoire: it co-purifies with the H3K4 demethylase RBP2 and colocalizes with elongating RNA Pol II, and Mrg15-null MEFs show delayed γH2AX and 53BP1 focus formation after irradiation, linking MORF4L1 to both transcription-coupled demethylation and the DNA damage response.\",\n      \"evidence\": \"Co-IP/mass spectrometry with demethylase assay; gamma irradiation of KO MEFs with immunofluorescence\",\n      \"pmids\": [\"17573780\", \"17961556\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which MORF4L1 facilitates damage signaling was unclear\", \"Whether RBP2 interaction is direct or bridged by other subunits was not resolved\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Direct binding of MORF4L1 to PALB2 was discovered, and disrupting this interaction elevated gene conversion and sister chromatid exchange rates, revealing that MORF4L1 constrains homologous recombination fidelity.\",\n      \"evidence\": \"Co-IP, pulldown with recombinant proteins, gene conversion and SCE assays with point mutants\",\n      \"pmids\": [\"19553677\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How MORF4L1 suppresses hyper-recombination mechanistically was not established\", \"Whether the chromodomain was required for this function was untested\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"MORF4L1 was shown to be the chromatin anchor for the entire BRCA complex (BRCA1–PALB2–BRCA2–RAD51); its loss abolished PALB2/BRCA2/RAD51 recruitment to damage sites, reduced homology-directed repair, and caused interstrand crosslink hypersensitivity, establishing a complete pathway from histone mark reading to repair factor loading.\",\n      \"evidence\": \"Purified complex analysis, chromatin fractionation, HR reporter assay, ICL sensitivity assay, and immunofluorescence of repair foci\",\n      \"pmids\": [\"20332121\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which histone mark was recognized at damage sites (H3K36me3 vs others) was not yet linked\", \"Temporal ordering of MORF4L1 arrival relative to damage sensing unknown\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Multiple studies refined the competition model for MORF4L1 complex assembly: NMR showed mSin3A and MORF4L1 compete for overlapping Pf1 binding surfaces, MORF4L1 occupied the CDK1 promoter during S phase cooperating with Tip60 for H4K12 acetylation, and loss of MRG15 in neural stem cells activated p53/p21 causing proliferation arrest.\",\n      \"evidence\": \"NMR structure of Sin3A–Pf1, ChIP at cdc2 promoter with HAT inhibitor, p21/p53 shRNA rescue in Mrg15-null NSCs\",\n      \"pmids\": [\"21440557\", \"21324423\", \"21621175\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether mutual exclusivity of Sin3A and MRG15 for Pf1 operates genome-wide was untested\", \"Direct HAT activity of Tip60 at CDK1 promoter not reconstituted in vitro\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Quantitative binding measurements established that MORF4L1 chromodomain binds H3K36me2/3 with weak (>100 µM) affinity, and that bivalent engagement with Pf1's PHD1 domain (reading unmodified H3K4) is required for Rpd3S/Sin3S targeting, explaining how a weak reader achieves specificity through multivalent contacts.\",\n      \"evidence\": \"ITC, peptide pulldown, domain deletion in the context of reconstituted Pf1–MRG15 complex\",\n      \"pmids\": [\"22728643\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo contribution of bivalent reading not validated by ChIP of mutants\", \"How other complex subunits contribute to chromatin affinity was unresolved\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"HDAC2-mediated deacetylation of MORF4L1 at K148 was shown to be required for homodimerization, revealing a post-translational switch that controls MORF4L1 self-assembly and potentially complex stoichiometry.\",\n      \"evidence\": \"Site-directed mutagenesis (K148R/L/Q), Co-IP of acetylation mimics, HDAC2 knockdown\",\n      \"pmids\": [\"24451372\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of dimerization for chromatin targeting or complex activity unknown\", \"Whether dimerization occurs within or between complexes was unresolved\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Conditional knockout in spermatocytes revealed that MORF4L1 reads H3K36me3 in introns and colocalizes with splicing factors PTBP1/PTBP2 to promote co-transcriptional splicing; loss caused intron retention in transition protein mRNAs and spermatogenic arrest, establishing a direct role in coupling histone marks to pre-mRNA processing.\",\n      \"evidence\": \"Conditional KO mouse, RNA-seq, ChIP, co-immunofluorescence\",\n      \"pmids\": [\"27573846\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether MORF4L1 directly binds PTBP1/PTBP2 or recruits them indirectly was not determined\", \"Generality of the splicing role beyond spermatogenesis was unclear\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Two key advances: (1) MORF4L1 was identified as a subunit of the Ash1 methyltransferase complex that stimulates H3K36 methylation and is required for Ash1 chromatin occupancy at Hox genes, and (2) ChIP-seq demonstrated that PALB2–MORF4L1 association with active genes depends on SETD2-deposited H3K36me3, completing the SETD2→H3K36me3→MRG15→PALB2 axis protecting replication through gene bodies.\",\n      \"evidence\": \"In vitro HMT assay with genetic rescue in Drosophila; ChIP-seq, camptothecin sensitivity, DNA combing in human cells\",\n      \"pmids\": [\"29158494\", \"28673974\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the Ash1–MRG15 complex uses the chromodomain for genomic targeting was not tested\", \"Structural basis of MRG15-mediated Ash1 activation was unknown\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Two independent crystal structures of the ASH1L–MRG15 complex resolved how MORF4L1 activates ASH1L: the MRG domain binds a conserved FxLP motif and displaces the autoinhibitory post-SET loop, opening the substrate binding pocket and inducing conformational coupling to the SAM-binding site.\",\n      \"evidence\": \"X-ray crystallography with in vitro methyltransferase assays and mutagenesis, independently replicated\",\n      \"pmids\": [\"30827841\", \"30827843\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether this allosteric mechanism operates on nucleosomal substrates was not demonstrated\", \"In vivo validation of the autoinhibitory loop displacement model was lacking\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"ChIP-seq in mouse liver revealed diurnally rhythmic MORF4L1 genomic binding at lipid synthesis genes, mediated by interaction with nuclear receptor LRH-1 rather than core clock factors, and MORF4L1 depletion impaired rhythmic Pol II recruitment and histone acetylation, revealing a metabolic regulatory function.\",\n      \"evidence\": \"ChIP-seq time-course, Co-IP, CRISPR targeting, RNA-seq\",\n      \"pmids\": [\"32694659\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which HAT complex mediates acetylation at lipid genes was not identified\", \"Whether LRH-1 interaction is direct or bridged was not structurally resolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Structural and stability studies showed that PALB2 binds the MRG domain with nanomolar affinity at a surface overlapping other partner binding sites, confirming mutually exclusive complex formation, and ubiquitylome analysis established that MORF4L1 protein levels are controlled by ubiquitin-proteasome degradation at K187 and K104.\",\n      \"evidence\": \"X-ray crystallography with SPR; large-scale ubiquitylome MS with proteasome inhibitors\",\n      \"pmids\": [\"34946951\", \"33848640\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the E3 ligase for basal turnover was unknown at this point\", \"Whether ubiquitination regulates MORF4L1 complex partitioning was untested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"MORF4L1 was discovered at the outer mitochondrial membrane where it deacetylates TUFM at K82/K91, targeting TUFM for ClpXP-mediated degradation; this impairs mitophagy and activates the NLRP3 inflammasome, driving NASH pathology—the first demonstration of a non-nuclear MORF4L1 function.\",\n      \"evidence\": \"IP-MS, Co-IP, mitochondrial fractionation, CRISPR KO, mitophagy and NLRP3 assays in NASH models\",\n      \"pmids\": [\"35985547\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of MORF4L1 targeting to mitochondria is unknown\", \"Whether MORF4L1 possesses intrinsic deacetylase activity or recruits an HDAC at mitochondria was not distinguished\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Two studies revised the ASH1L activation model and expanded DNA repair roles: NMR showed MORF4L1 does not alter ASH1L autoinhibitory loop conformation in solution but instead functions as a nucleosome-recruiting adapter via its chromodomain; separately, the ASH1L–MRG15 complex was found to deposit H3K4me3 genome-wide after UV damage to relocalize XPC and recruit the FACT chaperone, establishing a role in nucleotide excision repair.\",\n      \"evidence\": \"In vitro HMT assay with nucleosomes and NMR; ChIP-seq after UV irradiation with NER reconstitution\",\n      \"pmids\": [\"37527654\", \"37393406\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the nucleosome-recruiting and allosteric mechanisms are mutually exclusive or additive in vivo is unresolved\", \"How ASH1L–MRG15 switches from H3K36 to H3K4 methylation specificity upon UV damage is unexplained\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Multiple 2025 studies expanded the regulatory and functional landscape: CRBN was identified as an E3 ligase for MORF4L1, USP53 as a stabilizing deubiquitinase, phase separation via the IDR was linked to senescence suppression, a long isoform (MRG15L) was shown to weaken CDK1 regulation causing senescence, and MORF4L1 was found to promote cardiomyocyte proliferation at the Ccnd1 enhancer with Tip60/p300 and to cooperate with MyoD for myogenic differentiation.\",\n      \"evidence\": \"Proteomic/Co-IP degradation assays; phase separation/ChIP-seq; conditional KO mice in cardiac and muscle stem cells; isoform-specific binding and FACS analyses\",\n      \"pmids\": [\"39827217\", \"41061828\", \"40312521\", \"40483328\", \"41251000\", \"41580578\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Interplay between CRBN and USP53 in setting MORF4L1 levels is unexplored\", \"Whether phase separation is required for complex assembly in vivo needs validation\", \"MRG15L isoform mechanism for altered histone binding is structurally uncharacterized\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include: how MORF4L1 is directed to the outer mitochondrial membrane and whether it possesses intrinsic deacetylase activity; how cells partition a single MORF4L1 pool among mutually exclusive complexes (NuA4, Sin3S, ASH1L, PALB2); whether phase separation contributes to complex specificity in vivo; and how the ASH1L–MRG15 complex switches histone substrate specificity from H3K36 to H3K4 upon DNA damage.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural or biochemical mechanism for mitochondrial targeting\", \"No quantitative model of competitive complex partitioning\", \"Switch mechanism for ASH1L substrate specificity under damage conditions unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0042393\", \"supporting_discovery_ids\": [0, 12, 16, 22]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [2, 3, 8, 14, 17]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [1, 10, 19, 30]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [14, 17, 22]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [1, 2, 4, 6, 10, 16, 19]},\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [0, 15, 16, 24]},\n      {\"term_id\": \"GO:0005739\", \"supporting_discovery_ids\": [21]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [0, 2, 3, 10, 12, 14, 17]},\n      {\"term_id\": \"R-HSA-73894\", \"supporting_discovery_ids\": [7, 8, 9, 15, 23]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [1, 6, 10, 19, 30]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [4, 10, 25, 29]},\n      {\"term_id\": \"R-HSA-8953854\", \"supporting_discovery_ids\": [16]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [21]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [4, 30, 31]}\n    ],\n    \"complexes\": [\n      \"NuA4/Tip60 HAT complex\",\n      \"Sin3A/Rpd3S HDAC complex\",\n      \"ASH1L methyltransferase complex\",\n      \"BRCA/PALB2 repair complex\"\n    ],\n    \"partners\": [\n      \"PALB2\",\n      \"ASH1L\",\n      \"MRGBP\",\n      \"PHF12\",\n      \"SIN3A\",\n      \"KAT8\",\n      \"KAT5\",\n      \"TUFM\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}