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Showing MACROH2A2H2AFY2 is a alias.

MACROH2A2

Core histone macro-H2A.2 · UniProt Q9P0M6

Length
372 aa
Mass
40.1 kDa
Annotated
2026-06-10
31 papers in source corpus 16 papers cited in narrative 16 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

MACROH2A2 (H2afy2) is a replication-independent histone H2A variant that incorporates into nucleosomes to establish repressive chromatin domains and restrict chromatin plasticity during development, differentiation, and tumor suppression (PMID:11262398, PMID:19734898, PMID:30177554). It localizes to the inactive X chromosome, forming a Macro Chromatin Body that co-localizes with macroH2A1 (PMID:11262398, PMID:11331621), and broadly co-occupies developmental and pluripotency gene promoters together with PRC2/H3K27me3 (PMID:19734898, PMID:23463008). Its repressive function maps largely to the unstructured linker region, which restrains PARP1-dependent chromatin relaxation and is sufficient to rescue heterochromatin architecture in macroH2A-deficient cells; in contrast, its macrodomain is structurally incapable of binding ADP-ribose, distinguishing it from macroH2A1.1 (PMID:30177554). MacroH2A2 is deposited into chromatin in an ATP-dependent manner by the chromatin remodeler LSH to enforce transcriptional repression, a pathway disrupted by ICF4-causing LSH mutations (PMID:33159050), and its genomic boundaries are sculpted by a transcription-coupled 'pruning' mechanism in which the FACT complex removes it from actively transcribed regions (PMID:30291361). Functionally, macroH2A2 is the predominant macroH2A barrier to somatic reprogramming (PMID:23463008), acts downstream of Plcγ1/EpoR signaling in erythroid maturation (PMID:25394487), and represses self-renewal and metastatic outgrowth in multiple cancers, in part by shaping enhancer accessibility, antagonizing BRD4, and repressing a TM4SF1/AKT/NF-κB axis (PMID:36823213, PMID:38251858, PMID:36459552). Unlike macroH2A1, macroH2A2 does not interact with the MCM replicative helicase and does not regulate origin licensing on the inactive X, though its nucleosomes still slow replication progression there (PMID:39189450).

Mechanistic history

Synthesis pass · year-by-year structured walk · 10 steps
  1. 2001 High

    Established MACROH2A2 as a distinct second macroH2A gene and localized it to repressive chromatin, framing it as a candidate epigenetic silencer rather than a redundant copy of macroH2A1.

    Evidence Gene cloning, sequence analysis, and immunofluorescence co-localization with macroH2A1 on the inactive X chromosome

    PMID:11262398 PMID:11331621

    Open questions at the time
    • Functional consequence of inactive-X localization not tested
    • No identification of deposition machinery or partners
  2. 2009 High

    Showed macroH2A2 occupies developmental gene promoters alongside PRC2/H3K27me3 and is required for vertebrate development, placing it within a Polycomb-overlapping repressive program.

    Evidence Microarray chromatin occupancy with PRC2 co-occupancy analysis and morpholino knockdown in zebrafish

    PMID:19734898

    Open questions at the time
    • Did not separate macroH2A1 from macroH2A2 contributions
    • Mechanism of PRC2 co-occupancy unresolved
  3. 2013 High

    Identified macroH2A2 as the predominant macroH2A isoform barrier to somatic reprogramming, linking its chromatin marking to maintenance of differentiated cell identity.

    Evidence macroH2A double-knockout fibroblasts, iPS reprogramming assays, ChIP-seq, and isoform-specific rescue

    PMID:23463008

    Open questions at the time
    • Did not define how macroH2A2 is targeted to pluripotency genes
    • Relationship to UTX-dependent reactivation only correlative
  4. 2014 Medium

    Defined in vivo physiological roles (growth, reproduction, lipid metabolism), chromatin exchange dynamics, and a signaling-linked differentiation role downstream of Plcγ1/EpoR in erythropoiesis.

    Evidence Double-knockout mouse phenotyping and transcriptomics; SNAP-tag pulse-chase histone dynamics; shRNA epistasis in erythroid progenitors

    PMID:25102063 PMID:25312643 PMID:25394487

    Open questions at the time
    • Erythroid and metabolic findings from single labs
    • Molecular link between Plcγ1 signaling and macroH2A2 expression not resolved
  5. 2018 High

    Resolved the macrodomain structure showing macroH2A2 cannot bind ADP-ribose, and assigned its repressive activity to the unstructured linker that restrains PARP1-dependent chromatin relaxation.

    Evidence 1.7 Å crystal structure, quantitative ADP-ribose binding assays, live-cell PARP1 activity assays, and domain swap/deletion in cells

    PMID:30177554

    Open questions at the time
    • Functional role of the non-binding macrodomain pocket unknown
    • How linker mechanically restricts PARP1 not structurally defined
  6. 2018 High

    Revealed that macroH2A2 domain boundaries are set by transcription-coupled 'pruning', identifying FACT as the activity that removes it from active genes.

    Evidence Temporal ChIP-seq in reconstituted macroH2A-null fibroblasts, chemical transcription inhibition, locus-specific manipulation, and FACT depletion

    PMID:30291361

    Open questions at the time
    • How FACT distinguishes macroH2A2 from canonical H2A not defined
    • Fate of evicted macroH2A2 unknown
  7. 2020 High

    Identified the deposition machinery: LSH catalyzes ATP-dependent macroH2A2 incorporation required for repression, connecting macroH2A2 loss to ICF4 syndrome.

    Evidence Chemical-induced proximity tethering of LSH, ChIP-seq, siRNA, ATP-dependence assays, and ICF4 patient cell analysis

    PMID:33159050

    Open questions at the time
    • Whether LSH acts alone or with cofactors not resolved
    • Substrate selectivity for macroH2A2 versus macroH2A1 unclear
  8. 2022 Medium

    Extended macroH2A2 function to tumor suppression via enforcement of disseminated-cell dormancy and modulation of enhancer-promoter contacts and cytokine responses.

    Evidence Inducible in vivo PDX overexpression with metastasis assays and DEC2/NR2F1 loss-of-function; KO with Hi-C and cytokine transcriptomics in hepatoblastoma

    PMID:35732123 PMID:36459552

    Open questions at the time
    • Dormancy program effectors downstream of macroH2A2 not identified
    • Single-lab studies in specific cancer contexts
  9. 2023 Medium

    Showed macroH2A2 enforces cell identity and suppresses self-renewal by closing enhancer chromatin and antagonizing BRD4, with a parallel viral-mimicry sensitization in glioblastoma.

    Evidence ATAC-seq, ChIP-seq for macroH2A/H3K27ac, BRD4 occupancy, scATAC-seq, and patient-derived in vitro/in vivo loss-of-function models

    PMID:36823213 PMID:37244935

    Open questions at the time
    • Mechanism of BRD4 exclusion not biochemically defined
    • Viral mimicry trigger downstream of macroH2A2 unresolved
  10. 2024 High

    Distinguished macroH2A2 from macroH2A1 in replication control and identified a tumor-suppressive transcriptional axis, refining isoform-specific mechanism.

    Evidence Isoform-specific knockdown/knockout, replication focus imaging, DNA fiber and Co-IP assays with residue mutagenesis; macroH2A2 KD/overexpression with TM4SF1 rescue and in vivo tumor models

    PMID:38251858 PMID:39189450

    Open questions at the time
    • macroH2A2 lacks the MCM-interacting residue but its full replication role beyond slowing progression unclear
    • TM4SF1/AKT/NF-κB axis validated in single lab

Open questions

Synthesis pass · forward-looking unresolved questions
  • How macroH2A2's repressive linker, LSH-mediated deposition, and FACT-mediated removal are coordinated to produce locus- and cell-type-specific chromatin domains, and what distinguishes its function from macroH2A1 genome-wide, remains incompletely defined.
  • No structure of full macroH2A2 nucleosome with LSH or FACT
  • Determinants of isoform-specific targeting unknown
  • Direct protein partners of the macrodomain unidentified

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140110 transcription regulator activity 3 GO:0005198 structural molecule activity 2 GO:0098772 molecular function regulator activity 1
Localization
GO:0000228 nuclear chromosome 3 GO:0005634 nucleus 2 GO:0005694 chromosome 2
Pathway
R-HSA-1266738 Developmental Biology 3 R-HSA-4839726 Chromatin organization 2 R-HSA-74160 Gene expression (Transcription) 2
Complex memberships
Macro Chromatin Bodynucleosome

Evidence

Reading pass · 16 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2001 MACROH2A2 is a second macroH2A gene on human chromosome 10, encoding a protein with 68% amino acid identity to macroH2A1.2. It lacks the leucine zipper motif present in macroH2A1. By immunofluorescence, MACROH2A2 localizes to the inactive X chromosome in female cell nuclei, forming a Macro Chromatin Body co-localizing with macroH2A1. Gene cloning, sequence analysis, immunofluorescence on mouse tissue sections The Journal of biological chemistry High 11262398
2001 MacroH2A2, like macroH2A1, forms a Macro Chromatin Body coincident with an X chromosome in female nuclei and co-localizes with macroH2A1 on the inactive X chromosome. Unlike macroH2A1, macroH2A2 maps to a different chromosomal locus (consistent with chromosome 10). Immunofluorescence with epitope-tagged constructs, co-localization with macroH2A1 antibody Human molecular genetics High 11331621
2009 MacroH2A1 and macroH2A2, together, occupy promoters of key developmental and cell fate regulator genes in human male pluripotent cells, acting as a repressive mark that overlaps with Polycomb repressive complex 2 (PRC2/H3K27me3). Knockdown of macroH2A2 in zebrafish embryos produces severe developmental phenotypes, demonstrating a functional role in vertebrate development. Microarray-based chromatin occupancy analysis, co-occupancy with PRC2, morpholino knockdown in zebrafish Nature structural & molecular biology High 19734898
2013 MacroH2A2 is the predominant barrier to somatic cell reprogramming to induced pluripotency among macroH2A isoforms. MacroH2A1 and macroH2A2 co-occupy pluripotency genes together with H3K27me3 in wild-type fibroblasts, particularly at target genes of the H3K27me3 demethylase UTX, which are reactivated early in iPS reprogramming. Loss of both macroH2A isoforms (dKO) in differentiated cells reduces the epigenetic barrier, allowing more efficient reprogramming. macroH2A double-knockout mouse fibroblasts, iPS reprogramming assays, ChIP-seq for macroH2A1/2 and H3K27me3, isoform rescue experiments Nature communications High 23463008
2014 MacroH2A1 and macroH2A2 knockout mice show impaired prenatal and postnatal growth and reduced reproductive efficiency. MacroH2A2-containing nucleosomes substantially overlap in distribution with macroH2A1 and their effects on gene expression can be synergistic or opposing. In adult liver, macroH2A isoforms preferentially regulate lipid metabolism genes including the leptin receptor. Double knockout mouse model, gene expression profiling in fetal and adult liver, nucleosome distribution analysis Molecular and cellular biology High 25312643
2014 MacroH2A2 exhibits dynamic exchange at gene promoters in embryonic stem cells (particularly highly transcribed genes), while large intergenic blocks of macroH2A2 are stably associated. Upon differentiation to fibroblasts, macroH2A2 is gained in additional stable blocks in gene-poor regions and turnover at promoters is dampened. Pulse-chase genome-wide histone dynamics (SNAP-tag pulse labeling) in murine ES cells and somatic tissues PLoS genetics Medium 25102063
2014 Plcγ1 signaling downstream of Epo receptor activates macroH2A2 (H2afy2) expression, and macroH2A2 is a downstream effector of Plcγ1 required for erythroid maturation. Knockdown of macroH2A2 recapitulates the defect in erythroid differentiation caused by Plcγ1 inactivation. shRNA knockdown of Plcγ1 and macroH2A2 in erythroid progenitors, colony-forming assays, transcriptomics/DNA methylation analysis Cell death and differentiation Medium 25394487
2018 The crystal structure of the macrodomain of human macroH2A2 at 1.7 Å resolution reveals that its putative binding pocket exhibits marked structural differences compared with macroH2A1.1, rendering macroH2A2 unable to bind ADP-ribose. Quantitative binding assays confirm this specificity is conserved across vertebrate macroH2A isoforms. The unstructured linker region (common to all macroH2A proteins) exerts a repressive effect on PARP1-dependent chromatin relaxation upon DNA damage. The macroH2A linker alone is sufficient to rescue heterochromatin architecture in macroH2A-deficient cells. Crystal structure at 1.7 Å, quantitative ADP-ribose binding assays, live-cell PARP1 activity assays, domain swap/deletion experiments in cells EMBO reports High 30177554
2018 Active transcription defines the boundary of macroH2A2 chromatin domains via a 'pruning' mechanism: macroH2A2 is first broadly deposited genome-wide but is subsequently removed from actively transcribed regions by the FACT complex (facilitates chromatin transcription). Chemical inhibition of transcription counteracts pruning. Locus-specific gene activation depletes pre-existing macroH2A2, while gene silencing triggers ectopic macroH2A2 accumulation. Temporal genomic profiling (ChIP-seq) in macroH2A-null fibroblasts reconstituted with macroH2A2, chemical transcription inhibition, locus-specific transcriptional manipulation, FACT complex depletion Nature structural & molecular biology High 30291361
2020 LSH (chromatin remodeling protein) specifically induces macroH2A2 deposition into chromatin in an ATP-dependent manner. LSH-mediated macroH2A2 deposition is required for transcriptional repression at target loci. ICF4 syndrome mutations in LSH fail to induce macroH2A2 deposition, and ICF4 patient cells display reduced macroH2A2 enrichment and transcriptional reactivation. Chemical-induced proximity (CIP) tethering of LSH to engineered locus, ChIP-seq for macroH2A, siRNA knockdown of macroH2A, ICF4 patient cell analysis, ATP-dependence assay Nature communications High 33159050
2022 Inducible overexpression of macroH2A2 in vivo suppresses metastasis by enforcing a reversible growth arrest of disseminated cancer cells (dormancy). This dormancy program inhibits cell cycle and oncogenic signaling programs while up-regulating dormancy and senescence-associated inflammatory cytokines, and does not require dormancy-regulating transcription factors DEC2 or NR2F1. In vivo PDX models with inducible macroH2A2 expression, transcriptomic analysis, in vivo metastasis assays, DEC2/NR2F1 loss-of-function Science advances Medium 36459552
2022 MacroH2A1.2 and macroH2A2 modulate enhancer-promoter contact frequency and enhancer activity in hepatoblastoma cells. Their removal affects NF-κB-mediated transcriptional responses to TNFα (facilitating the response) and suppresses response to IFN-γ. MacroH2A2 has a stronger contribution to gene repression than macroH2A1.2. Knockout of macroH2A1.2 and macroH2A2 in hepatoblastoma cells, Hi-C/chromatin conformation analysis, transcriptomic response to cytokines Cell reports Medium 35732123
2023 MacroH2A2 shapes chromatin accessibility at enhancer elements to antagonize transcriptional programs of self-renewal in glioblastoma. MacroH2A2 also sensitizes cells to small molecule-mediated cell death via activation of a viral mimicry response. These findings are based on patient-derived in vitro and in vivo glioblastoma models. ATAC-seq for chromatin accessibility, transcriptomic profiling, patient-derived xenograft in vivo models, loss-of-function studies Nature communications Medium 37244935
2023 MacroH2A2 marks a subset of inactive enhancers (macro-bound enhancers) lacking H3K27ac in a cell type-specific manner, maintaining cell identity. MacroH2A2 acts as a negative regulator of BRD4 chromatin occupancy at these enhancers. MacroH2A deficiency in mammary stem cells facilitates increased activity of transcription factors associated with stem cell activity. ChIP-seq for macroH2A and H3K27ac, BRD4 occupancy assays, single-cell ATAC-seq in mouse mammary stem cells, loss-of-function Communications biology Medium 36823213
2024 MacroH2A1, but not macroH2A2, regulates the number of replication foci and DNA loop sizes (replicons) on the inactive X chromosome by interacting with the replicative helicase (MCM complex). This interaction is mediated by a phenylalanine residue in macroH2A1 that is not conserved in macroH2A2, and maps to the C-terminus of Mcm3. MacroH2A2-containing nucleosomes slow replication progression rate on the Xi (shared with macroH2A1), but macroH2A2 does NOT regulate helicase loading. Knockdown/knockout of individual macroH2A isoforms, replication focus imaging, DNA fiber assays, Co-IP of macroH2A1 with MCM helicase, domain mutagenesis (phenylalanine substitution) Nucleic acids research High 39189450
2024 MacroH2A2 suppresses breast cancer malignancy by repressing TM4SF1 expression. The mH2A2/TM4SF1 axis controls the AKT/NF-κB signaling pathway; macroH2A2 knockdown activates AKT/NF-κB and increases MMP13 expression and secretion. Overexpression of macroH2A2 reduced tumor growth and lung metastasis in vivo. Knockdown/overexpression of macroH2A2 in breast cancer cells, microarray gene expression, TM4SF1 rescue experiments, in vivo tumor and metastasis models, AKT/NF-κB pathway analysis Molecular carcinogenesis Medium 38251858

Source papers

Stage 0 corpus · 31 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2013 MacroH2A histone variants act as a barrier upon reprogramming towards pluripotency. Nature communications 162 23463008
2009 The histone variant macroH2A is an epigenetic regulator of key developmental genes. Nature structural & molecular biology 160 19734898
2009 Histone macroH2A isoforms predict the risk of lung cancer recurrence. Oncogene 152 19648962
2001 Histone H2A variants and the inactive X chromosome: identification of a second macroH2A variant. Human molecular genetics 142 11331621
2001 MACROH2A2, a new member of the MARCOH2A core histone family. The Journal of biological chemistry 129 11262398
2014 Expression and functionality of histone H2A variants in cancer. Oncotarget 63 25003966
2018 MacroH2A histone variants limit chromatin plasticity through two distinct mechanisms. EMBO reports 61 30177554
2014 Mice without macroH2A histone variants. Molecular and cellular biology 61 25312643
2011 X chromosome inactivation and differentiation occur readily in ES cells doubly-deficient for macroH2A1 and macroH2A2. PloS one 38 21738686
2020 LSH mediates gene repression through macroH2A deposition. Nature communications 34 33159050
2018 Transcription-associated histone pruning demarcates macroH2A chromatin domains. Nature structural & molecular biology 32 30291361
2014 Epo-induced erythroid maturation is dependent on Plcγ1 signaling. Cell death and differentiation 32 25394487
2015 Mechanism of Action of 2-Aminobenzamide HDAC Inhibitors in Reversing Gene Silencing in Friedreich's Ataxia. Frontiers in neurology 26 25798128
2022 MacroH2A impedes metastatic growth by enforcing a discrete dormancy program in disseminated cancer cells. Science advances 24 36459552
2014 A system for genome-wide histone variant dynamics in ES cells reveals dynamic MacroH2A2 replacement at promoters. PLoS genetics 23 25102063
2018 Comprehensive analysis of coexpressed long noncoding RNAs and genes in breast cancer. The journal of obstetrics and gynaecology research 16 30362198
2008 Spatial distribution of histone isoforms on the bovine active and inactive X chromosomes. Sexual development : genetics, molecular biology, evolution, endocrinology, embryology, and pathology of sex determination and differentiation 16 18418031
2022 MacroH2As regulate enhancer-promoter contacts affecting enhancer activity and sensitivity to inflammatory cytokines. Cell reports 13 35732123
2015 Loss of histone variant macroH2A2 expression associates with progression of anal neoplasm. Journal of clinical pathology 13 26658220
2023 MacroH2A histone variants modulate enhancer activity to repress oncogenic programs and cellular reprogramming. Communications biology 12 36823213
2018 A genome wide association study identifies new genes potentially associated with eyelid sagging. Experimental dermatology 12 29654602
2023 macroH2A2 antagonizes epigenetic programs of stemness in glioblastoma. Nature communications 11 37244935
2023 Unveiling Circular RNA-Mediated Regulatory Mechanisms in Necroptosis in Premature Ovarian Failure. Frontiers in bioscience (Landmark edition) 11 38062819
2020 An integrative Bayesian network approach to highlight key drivers in systemic lupus erythematosus. Arthritis research & therapy 11 32576231
2019 Deficiency of 15-LOX-1 Induces Radioresistance through Downregulation of MacroH2A2 in Colorectal Cancer. Cancers 11 31717983
2022 Analysis of histone variant constraint and tissue expression suggests five potential novel human disease genes: H2AFY2, H2AFZ, H2AFY, H2AFV, H1F0. Human genetics 7 35072799
2024 Histone variant macroH2A1 regulates synchronous firing of replication origins in the inactive X chromosome. Nucleic acids research 3 39189450
2024 Breast cancer malignancy is governed by regulation of the macroH2A2/TM4SF1 axis, the AKT/NF-κB pathway, and elevated MMP13 expression. Molecular carcinogenesis 2 38251858
2024 Molecular characterization of histone gene in golden pompano (Trachinotus ovatus) and antimicrobial activity of its derived peptides. Fish & shellfish immunology 2 39209007
2025 Loss of histone macroH2A1.1 causes kidney abnormalities secondary to a change in nutrient metabolization. Science advances 1 41134882
2024 Integrated Quantitative Proteomics and Phosphoproteomics Analysis Reveals the Dynamic Process of Buffalo (Bubalus bubalis) Spermatogenesis. Reproduction in domestic animals = Zuchthygiene 0 39697112

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