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Rabbit Anti-Histone H3, trimethyl (Lys27) Polyclonal antibody, Unconjugated

RRID:AB_310624

Antibody ID

AB_310624

Target Antigen

Histone H3, trimethyl (Lys27) human, mouse

Proper Citation

(Millipore Cat# 07-449, RRID:AB_310624)

Clonality

polyclonal antibody

Comments

Validated for Fly by Xia et al 2016 10.18632/aging.101107; seller recommendations: Blocking/Neutralize; Functional Assay; Immunocytochemistry; Immunoprecipitation; Other; Western Blot; Western Blotting, Immunocytochemistry

Host Organism

rabbit

Vendor

Millipore

Exit from Naive Pluripotency Induces a Transient X Chromosome Inactivation-like State in Males.

  • Sousa EJ
  • Cell Stem Cell
  • 2018 Jun 1

Literature context:


Abstract:

A hallmark of naive pluripotency is the presence of two active X chromosomes in females. It is not clear whether prevention of X chromosome inactivation (XCI) is mediated by gene networks that preserve the naive state. Here, we show that robust naive pluripotent stem cell (nPSC) self-renewal represses expression of Xist, the master regulator of XCI. We found that nPSCs accumulate Xist on the male X chromosome and on both female X chromosomes as they become NANOG negative at the onset of differentiation. This is accompanied by the appearance of a repressive chromatin signature and partial X-linked gene silencing, suggesting a transient and rapid XCI-like state in male nPSCs. In the embryo, Xist is transiently expressed in males and in females from both X chromosomes at the onset of naive epiblast differentiation. In conclusion, we propose that XCI initiation is gender independent and triggered by destabilization of naive identity, suggesting that gender-specific mechanisms follow, rather than precede, XCI initiation.

Funding information:
  • NHLBI NIH HHS - HL085036(United States)

The SS18-SSX Fusion Oncoprotein Hijacks BAF Complex Targeting and Function to Drive Synovial Sarcoma.

  • McBride MJ
  • Cancer Cell
  • 2018 Jun 11

Literature context:


Abstract:

Synovial sarcoma (SS) is defined by the hallmark SS18-SSX fusion oncoprotein, which renders BAF complexes aberrant in two manners: gain of SSX to the SS18 subunit and concomitant loss of BAF47 subunit assembly. Here we demonstrate that SS18-SSX globally hijacks BAF complexes on chromatin to activate an SS transcriptional signature that we define using primary tumors and cell lines. Specifically, SS18-SSX retargets BAF complexes from enhancers to broad polycomb domains to oppose PRC2-mediated repression and activate bivalent genes. Upon suppression of SS18-SSX, reassembly of BAF47 restores enhancer activation, but is not required for proliferative arrest. These results establish a global hijacking mechanism for SS18-SSX on chromatin, and define the distinct contributions of two concurrent BAF complex perturbations.

Funding information:
  • NIAID NIH HHS - R01 AI076479(United States)

PRC1 Fine-tunes Gene Repression and Activation to Safeguard Skin Development and Stem Cell Specification.

  • Cohen I
  • Cell Stem Cell
  • 2018 May 3

Literature context:


Abstract:

Polycomb repressive complexes (PRCs) 1 and 2 are essential chromatin regulators of cell identity. PRC1, a dominant executer of Polycomb-mediated control, functions as multiple sub-complexes that possess catalytic-dependent H2AK119 mono-ubiquitination (H2AK119ub) and catalytic-independent activities. Here, we show that, despite its well-established repressor functions, PRC1 binds to both silent and active genes. Through in vivo loss-of-function studies, we show that global PRC1 function is essential for skin development and stem cell (SC) specification, whereas PRC1 catalytic activity is dispensable. Further dissection demonstrated that both canonical and non-canonical PRC1 complexes bind to repressed genes, marked by H2AK119ub and PRC2-mediated H3K27me3. Interestingly, loss of canonical PRC1, PRC1 catalytic activity, or PRC2 leads to expansion of mechanosensitive Merkel cells in neonatal skin. Non-canonical PRC1 complexes, however, also bind to and promote expression of genes critical for skin development and SC formation. Together, our findings highlight PRC1's diverse roles in executing a precise developmental program.

Funding information:
  • NIAMS NIH HHS - R00 AR057817()
  • NIAMS NIH HHS - R01 AR063724()
  • NINDS NIH HHS - R21 NS055261(United States)

Epigenetic drift of H3K27me3 in aging links glycolysis to healthy longevity in Drosophila.

  • Ma Z
  • Elife
  • 2018 May 29

Literature context:


Abstract:

Epigenetic alteration has been implicated in aging. However, the mechanism by which epigenetic change impacts aging remains to be understood. H3K27me3, a highly conserved histone modification signifying transcriptional repression, is marked and maintained by Polycomb Repressive Complexes (PRCs). Here, we explore the mechanism by which age-modulated increase of H3K27me3 impacts adult lifespan. Using Drosophila, we reveal that aging leads to loss of fidelity in epigenetic marking and drift of H3K27me3 and consequential reduction in the expression of glycolytic genes with negative effects on energy production and redox state. We show that a reduction of H3K27me3 by PRCs-deficiency promotes glycolysis and healthy lifespan. While perturbing glycolysis diminishes the pro-lifespan benefits mediated by PRCs-deficiency, transgenic increase of glycolytic genes in wild-type animals extends longevity. Together, we propose that epigenetic drift of H3K27me3 is one of the molecular mechanisms that contribute to aging and that stimulation of glycolysis promotes metabolic health and longevity.

Funding information:
  • Cancer Prevention and Research Institute of Texas - RP170387()
  • National Institutes of Health - GM120033()
  • National Natural Science Foundation of China - 21575151()
  • National Natural Science Foundation of China - 31371326()
  • National Natural Science Foundation of China - 31500665()
  • National Natural Science Foundation of China - 31530041()
  • National Natural Science Foundation of China - 31671428()
  • National Natural Science Foundation of China - 81770143()
  • National Program on Key Research Projects of China - 2016YFA0501900()
  • National Science Foundation - DMS-1263932()
  • National Science Foundation of China - 31371326()
  • National Science Foundation of China - 31500665()
  • National Science Foundation of China - 31530041()
  • National Science Foundation of China - 31671428()
  • National Science Foundation of China - 81770143()
  • NIDDK NIH HHS - R01 DK077200-05(United States)
  • NIGMS NIH HHS - R01 GM120033()

A Family of Vertebrate-Specific Polycombs Encoded by the LCOR/LCORL Genes Balance PRC2 Subtype Activities.

  • Conway E
  • Mol. Cell
  • 2018 May 3

Literature context:


Abstract:

The polycomb repressive complex 2 (PRC2) consists of core subunits SUZ12, EED, RBBP4/7, and EZH1/2 and is responsible for mono-, di-, and tri-methylation of lysine 27 on histone H3. Whereas two distinct forms exist, PRC2.1 (containing one polycomb-like protein) and PRC2.2 (containing AEBP2 and JARID2), little is known about their differential functions. Here, we report the discovery of a family of vertebrate-specific PRC2.1 proteins, "PRC2 associated LCOR isoform 1" (PALI1) and PALI2, encoded by the LCOR and LCORL gene loci, respectively. PALI1 promotes PRC2 methyltransferase activity in vitro and in vivo and is essential for mouse development. Pali1 and Aebp2 define mutually exclusive, antagonistic PRC2 subtypes that exhibit divergent H3K27-tri-methylation activities. The balance of these PRC2.1/PRC2.2 activities is required for the appropriate regulation of polycomb target genes during differentiation. PALI1/2 potentially link polycombs with transcriptional co-repressors in the regulation of cellular identity during development and in cancer.

Funding information:
  • NHLBI NIH HHS - R01 HL095783-03(United States)

Ezh2 and Runx1 Mutations Collaborate to Initiate Lympho-Myeloid Leukemia in Early Thymic Progenitors.

  • Booth CAG
  • Cancer Cell
  • 2018 Feb 12

Literature context:


Abstract:

Lympho-myeloid restricted early thymic progenitors (ETPs) are postulated to be the cell of origin for ETP leukemias, a therapy-resistant leukemia associated with frequent co-occurrence of EZH2 and RUNX1 inactivating mutations, and constitutively activating signaling pathway mutations. In a mouse model, we demonstrate that Ezh2 and Runx1 inactivation targeted to early lymphoid progenitors causes a marked expansion of pre-leukemic ETPs, showing transcriptional signatures characteristic of ETP leukemia. Addition of a RAS-signaling pathway mutation (Flt3-ITD) results in an aggressive leukemia co-expressing myeloid and lymphoid genes, which can be established and propagated in vivo by the expanded ETPs. Both mouse and human ETP leukemias show sensitivity to BET inhibition in vitro and in vivo, which reverses aberrant gene expression induced by Ezh2 inactivation.

Funding information:
  • Medical Research Council - G0501838()
  • Medical Research Council - MC_UU_12009/6()
  • Medical Research Council - MR/M00919X/1()
  • Medical Research Council - MR/M010392/1()
  • NHGRI NIH HHS - HG02357(United States)
  • Worldwide Cancer Research - 14-1069()

Lineage-Determining Transcription Factor TCF-1 Initiates the Epigenetic Identity of T Cells.

  • Johnson JL
  • Immunity
  • 2018 Feb 20

Literature context:


Abstract:

T cell development is orchestrated by transcription factors that regulate the expression of genes initially buried within inaccessible chromatin, but the transcription factors that establish the regulatory landscape of the T cell lineage remain unknown. Profiling chromatin accessibility at eight stages of T cell development revealed the selective enrichment of TCF-1 at genomic regions that became accessible at the earliest stages of development. TCF-1 was further required for the accessibility of these regulatory elements and at the single-cell level, it dictated a coordinate opening of chromatin in T cells. TCF-1 expression in fibroblasts generated de novo chromatin accessibility even at chromatin regions with repressive marks, inducing the expression of T cell-restricted genes. These results indicate that a mechanism by which TCF-1 controls T cell fate is through its widespread ability to target silent chromatin and establish the epigenetic identity of T cells.

Funding information:
  • NIAID NIH HHS - K22 AI112570()
  • NIAID NIH HHS - R01 AI047833()
  • NIAID NIH HHS - R01 AI105343()
  • NIAID NIH HHS - U19 AI082630()
  • NINDS NIH HHS - NS061856(United States)

Engineered Multivalent Sensors to Detect Coexisting Histone Modifications in Living Stem Cells.

  • Delachat AM
  • Cell Chem Biol
  • 2018 Jan 18

Literature context:


Abstract:

The regulation of fundamental processes such as gene expression or cell differentiation involves chromatin states, demarcated by combinatorial histone post-translational modification (PTM) patterns. The subnuclear organization and dynamics of chromatin states is not well understood, as tools for their detection and modulation in live cells are lacking. Here, we report the development of genetically encoded chromatin-sensing multivalent probes, cMAPs, selective for bivalent chromatin, a PTM pattern associated with pluripotency in embryonic stem cells (ESCs). cMAPs were engineered from a set of PTM-binding (reader) proteins and optimized using synthetic nucleosomes carrying defined PTMs. Applied in live ESCs, cMAPs formed discrete subnuclear foci, revealing the organization of bivalent chromatin into local clusters. Moreover, cMAPs enabled direct monitoring of the loss of bivalency upon treatment with small-molecule epigenetic modulators. cMAPs thus provide a versatile platform to monitor chromatin state dynamics in live cells.

Funding information:
  • PHS HHS - P60-05130(United States)

Early-Life Gene Expression in Neurons Modulates Lasting Epigenetic States.

  • Stroud H
  • Cell
  • 2017 Nov 16

Literature context:


Abstract:

In mammals, the environment plays a critical role in promoting the final steps in neuronal development during the early postnatal period. While epigenetic factors are thought to contribute to this process, the underlying molecular mechanisms remain poorly understood. Here, we show that in the brain during early life, the DNA methyltransferase DNMT3A transiently binds across transcribed regions of lowly expressed genes, and its binding specifies the pattern of DNA methylation at CA sequences (mCA) within these genes. We find that DNMT3A occupancy and mCA deposition within the transcribed regions of genes is negatively regulated by gene transcription and may be modified by early-life experience. Once deposited, mCA is bound by the methyl-DNA-binding protein MECP2 and functions in a rheostat-like manner to fine-tune the cell-type-specific transcription of genes that are critical for brain function.

Funding information:
  • NINDS NIH HHS - F32 NS089186()
  • NINDS NIH HHS - R01 NS048276()
  • NINDS NIH HHS - T32 NS007484()

Zfp281 is essential for mouse epiblast maturation through transcriptional and epigenetic control of Nodal signaling.

  • Huang X
  • Elife
  • 2017 Nov 23

Literature context:


Abstract:

Pluripotency is defined by a cell's potential to differentiate into any somatic cell type. How pluripotency is transited during embryo implantation, followed by cell lineage specification and establishment of the basic body plan, is poorly understood. Here we report the transcription factor Zfp281 functions in the exit from naive pluripotency occurring coincident with pre-to-post-implantation mouse embryonic development. By characterizing Zfp281 mutant phenotypes and identifying Zfp281 gene targets and protein partners in developing embryos and cultured pluripotent stem cells, we establish critical roles for Zfp281 in activating components of the Nodal signaling pathway and lineage-specific genes. Mechanistically, Zfp281 cooperates with histone acetylation and methylation complexes at target gene enhancers and promoters to exert transcriptional activation and repression, as well as epigenetic control of epiblast maturation leading up to anterior-posterior axis specification. Our study provides a comprehensive molecular model for understanding pluripotent state progressions in vivo during mammalian embryonic development.

Funding information:
  • NIDA NIH HHS - K02 DA021863-01A1(United States)

H3.3K27M Cooperates with Trp53 Loss and PDGFRA Gain in Mouse Embryonic Neural Progenitor Cells to Induce Invasive High-Grade Gliomas.

  • Pathania M
  • Cancer Cell
  • 2017 Nov 13

Literature context:


Abstract:

Gain-of-function mutations in histone 3 (H3) variants are found in a substantial proportion of pediatric high-grade gliomas (pHGG), often in association with TP53 loss and platelet-derived growth factor receptor alpha (PDGFRA) amplification. Here, we describe a somatic mouse model wherein H3.3K27M and Trp53 loss alone are sufficient for neoplastic transformation if introduced in utero. H3.3K27M-driven lesions are clonal, H3K27me3 depleted, Olig2 positive, highly proliferative, and diffusely spreading, thus recapitulating hallmark molecular and histopathological features of pHGG. Addition of wild-type PDGFRA decreases latency and increases tumor invasion, while ATRX knockdown is associated with more circumscribed tumors. H3.3K27M-tumor cells serially engraft in recipient mice, and preliminary drug screening reveals mutation-specific vulnerabilities. Overall, we provide a faithful H3.3K27M-pHGG model which enables insights into oncohistone pathogenesis and investigation of future therapies.

Funding information:
  • NCI NIH HHS - P01 CA196539()

The Elongation Factor Spt6 Maintains ESC Pluripotency by Controlling Super-Enhancers and Counteracting Polycomb Proteins.

  • Wang AH
  • Mol. Cell
  • 2017 Oct 19

Literature context:


Abstract:

Spt6 coordinates nucleosome dis- and re-assembly, transcriptional elongation, and mRNA processing. Here, we report that depleting Spt6 in embryonic stem cells (ESCs) reduced expression of pluripotency factors, increased expression of cell-lineage-affiliated developmental regulators, and induced cell morphological and biochemical changes indicative of ESC differentiation. Selective downregulation of pluripotency factors upon Spt6 depletion may be mechanistically explained by its enrichment at ESC super-enhancers, where Spt6 controls histone H3K27 acetylation and methylation and super-enhancer RNA transcription. In ESCs, Spt6 interacted with the PRC2 core subunit Suz12 and prevented H3K27me3 accumulation at ESC super-enhancers and associated promoters. Biochemical as well as functional experiments revealed that Spt6 could compete for binding of the PRC2 methyltransferase Ezh2 to Suz12 and reduce PRC2 chromatin engagement. Thus, in addition to serving as a histone chaperone and transcription elongation factor, Spt6 counteracts repression by opposing H3K27me3 deposition at critical genomic regulatory regions.

Funding information:
  • Intramural NIH HHS - ZIA AR041126-17()

Cohesin Loss Eliminates All Loop Domains.

  • Rao SSP
  • Cell
  • 2017 Oct 5

Literature context:


Abstract:

The human genome folds to create thousands of intervals, called "contact domains," that exhibit enhanced contact frequency within themselves. "Loop domains" form because of tethering between two loci-almost always bound by CTCF and cohesin-lying on the same chromosome. "Compartment domains" form when genomic intervals with similar histone marks co-segregate. Here, we explore the effects of degrading cohesin. All loop domains are eliminated, but neither compartment domains nor histone marks are affected. Loss of loop domains does not lead to widespread ectopic gene activation but does affect a significant minority of active genes. In particular, cohesin loss causes superenhancers to co-localize, forming hundreds of links within and across chromosomes and affecting the regulation of nearby genes. We then restore cohesin and monitor the re-formation of each loop. Although re-formation rates vary greatly, many megabase-sized loops recovered in under an hour, consistent with a model where loop extrusion is rapid.

Funding information:
  • NIGMS NIH HHS - T32 GM008294()

Evolutionarily Conserved Principles Predict 3D Chromatin Organization.

  • Rowley MJ
  • Mol. Cell
  • 2017 Sep 7

Literature context:


Abstract:

Topologically associating domains (TADs), CTCF loop domains, and A/B compartments have been identified as important structural and functional components of 3D chromatin organization, yet the relationship between these features is not well understood. Using high-resolution Hi-C and HiChIP, we show that Drosophila chromatin is organized into domains we term compartmental domains that correspond precisely with A/B compartments at high resolution. We find that transcriptional state is a major predictor of Hi-C contact maps in several eukaryotes tested, including C. elegans and A. thaliana. Architectural proteins insulate compartmental domains by reducing interaction frequencies between neighboring regions in Drosophila, but CTCF loops do not play a distinct role in this organism. In mammals, compartmental domains exist alongside CTCF loop domains to form topological domains. The results suggest that compartmental domains are responsible for domain structure in all eukaryotes, with CTCF playing an important role in domain formation in mammals.

Funding information:
  • NIGMS NIH HHS - F32 GM113570()
  • NIGMS NIH HHS - R01 GM035463()

Chronic Cigarette Smoke-Induced Epigenomic Changes Precede Sensitization of Bronchial Epithelial Cells to Single-Step Transformation by KRAS Mutations.

  • Vaz M
  • Cancer Cell
  • 2017 Sep 11

Literature context:


Abstract:

We define how chronic cigarette smoke-induced time-dependent epigenetic alterations can sensitize human bronchial epithelial cells for transformation by a single oncogene. The smoke-induced chromatin changes include initial repressive polycomb marking of genes, later manifesting abnormal DNA methylation by 10 months. At this time, cells exhibit epithelial-to-mesenchymal changes, anchorage-independent growth, and upregulated RAS/MAPK signaling with silencing of hypermethylated genes, which normally inhibit these pathways and are associated with smoking-related non-small cell lung cancer. These cells, in the absence of any driver gene mutations, now transform by introducing a single KRAS mutation and form adenosquamous lung carcinomas in mice. Thus, epigenetic abnormalities may prime for changing oncogene senescence to addiction for a single key oncogene involved in lung cancer initiation.

Funding information:
  • NCI NIH HHS - P30 CA006973()
  • NCI NIH HHS - R01 CA043318()
  • NCI NIH HHS - R01 CA121113()
  • NCI NIH HHS - R01 CA170550()
  • NCI NIH HHS - R01 CA185357()
  • NCI NIH HHS - U10 CA180950()
  • NIEHS NIH HHS - R01 ES011858()
  • NIEHS NIH HHS - R01 ES023183()

Myc Regulates Chromatin Decompaction and Nuclear Architecture during B Cell Activation.

  • Kieffer-Kwon KR
  • Mol. Cell
  • 2017 Aug 17

Literature context:


Abstract:

50 years ago, Vincent Allfrey and colleagues discovered that lymphocyte activation triggers massive acetylation of chromatin. However, the molecular mechanisms driving epigenetic accessibility are still unknown. We here show that stimulated lymphocytes decondense chromatin by three differentially regulated steps. First, chromatin is repositioned away from the nuclear periphery in response to global acetylation. Second, histone nanodomain clusters decompact into mononucleosome fibers through a mechanism that requires Myc and continual energy input. Single-molecule imaging shows that this step lowers transcription factor residence time and non-specific collisions during sampling for DNA targets. Third, chromatin interactions shift from long range to predominantly short range, and CTCF-mediated loops and contact domains double in numbers. This architectural change facilitates cognate promoter-enhancer contacts and also requires Myc and continual ATP production. Our results thus define the nature and transcriptional impact of chromatin decondensation and reveal an unexpected role for Myc in the establishment of nuclear topology in mammalian cells.

FXR1 regulates transcription and is required for growth of human cancer cells with TP53/FXR2 homozygous deletion.

  • Fan Y
  • Elife
  • 2017 Aug 2

Literature context:


Abstract:

Tumor suppressor p53 prevents cell transformation by inducing apoptosis and other responses. Homozygous TP53 deletion occurs in various types of human cancers for which no therapeutic strategies have yet been reported. TCGA database analysis shows that the TP53 homozygous deletion locus mostly exhibits co-deletion of the neighboring gene FXR2, which belongs to the Fragile X gene family. Here, we demonstrate that inhibition of the remaining family member FXR1 selectively blocks cell proliferation in human cancer cells containing homozygous deletion of both TP53 and FXR2 in a collateral lethality manner. Mechanistically, in addition to its RNA-binding function, FXR1 recruits transcription factor STAT1 or STAT3 to gene promoters at the chromatin interface and regulates transcription thus, at least partially, mediating cell proliferation. Our study anticipates that inhibition of FXR1 is a potential therapeutic approach to targeting human cancers harboring TP53 homozygous deletion.

JMJD3 Is Crucial for the Female AVPV RIP-Cre Neuron-Controlled Kisspeptin-Estrogen Feedback Loop and Reproductive Function.

  • Song A
  • Endocrinology
  • 2017 Jun 1

Literature context:


Abstract:

The hypothalamic-pituitary-gonadal axis controls development, reproduction, and metabolism. Although most studies have focused on the hierarchy from the brain to the gonad, many questions remain unresolved concerning the feedback from the gonad to the central nervous system, especially regarding the potential epigenetic modifications in hypothalamic neurons. In the present report, we generated genetically modified mice lacking histone H3 lysine 27 (H3K27) demethylase Jumonji domain-containing 3 (JMJD3) in hypothalamic rat-insulin-promoter-expressing neurons (RIP-Cre neurons). The female mutant mice displayed late-onset obesity owing to reduced locomotor activity and decreased energy expenditure. JMJD3 deficiency in RIP-Cre neurons also results in delayed pubertal onset, an irregular estrous cycle, impaired fertility, and accelerated ovarian failure in female mice owing to the dysregulation of the hypothalamic-ovarian axis. We found that JMJD3 directly regulates Kiss1 gene expression by binding to the Kiss1 promoter and triggering H3K27me3 demethylation in the anteroventral periventricular (AVPV) nucleus. Further study confirmed that the aberrations arose from impaired kisspeptin signaling in the hypothalamic AVPV nucleus and subsequent estrogen deficiency. Estrogen replacement therapy can reverse obesity in mutant mice. Moreover, we demonstrated that Jmjd3 is an estrogen target gene in the hypothalamus. These results provide direct genetic and molecular evidence that JMJD3 is a key mediator for the kisspeptin-estrogen feedback loop.

The Dynamic Epigenetic Landscape of the Retina During Development, Reprogramming, and Tumorigenesis.

  • Aldiri I
  • Neuron
  • 2017 May 3

Literature context:


Abstract:

In the developing retina, multipotent neural progenitors undergo unidirectional differentiation in a precise spatiotemporal order. Here we profile the epigenetic and transcriptional changes that occur during retinogenesis in mice and humans. Although some progenitor genes and cell cycle genes were epigenetically silenced during retinogenesis, the most dramatic change was derepression of cell-type-specific differentiation programs. We identified developmental-stage-specific super-enhancers and showed that most epigenetic changes are conserved in humans and mice. To determine how the epigenome changes during tumorigenesis and reprogramming, we performed integrated epigenetic analysis of murine and human retinoblastomas and induced pluripotent stem cells (iPSCs) derived from murine rod photoreceptors. The retinoblastoma epigenome mapped to the developmental stage when retinal progenitors switch from neurogenic to terminal patterns of cell division. The epigenome of retinoblastomas was more similar to that of the normal retina than that of retina-derived iPSCs, and we identified retina-specific epigenetic memory.

Funding information:
  • Howard Hughes Medical Institute - P30 CA021765()
  • NCI NIH HHS - R01 CA168875()
  • NEI NIH HHS - R01 EY014867()
  • NEI NIH HHS - R01 EY018599()
  • NEI NIH HHS - R01 EY023619()

Delayed Accumulation of H3K27me3 on Nascent DNA Is Essential for Recruitment of Transcription Factors at Early Stages of Stem Cell Differentiation.

  • Petruk S
  • Mol. Cell
  • 2017 Apr 20

Literature context:


Abstract:

Recruitment of transcription factors (TFs) to repressed genes in euchromatin is essential to activate new transcriptional programs during cell differentiation. However, recruitment of all TFs, including pioneer factors, is impeded by condensed H3K27me3-containing chromatin. Single-cell and gene-specific analyses revealed that, during the first hours of induction of differentiation of mammalian embryonic stem cells (ESCs), accumulation of the repressive histone mark H3K27me3 is delayed after DNA replication, indicative of a decondensed chromatin structure in all regions of the replicating genome. This delay provides a critical "window of opportunity" for recruitment of lineage-specific TFs to DNA. Increasing the levels of post-replicative H3K27me3 or preventing S phase entry inhibited recruitment of new TFs to DNA and significantly blocked cell differentiation. These findings suggest that recruitment of lineage-specifying TFs occurs soon after replication and is facilitated by a decondensed chromatin structure. This insight may explain the developmental plasticity of stem cells and facilitate their exploitation for therapeutic purposes.

Funding information:
  • NCI NIH HHS - R01 CA164834()
  • NHLBI NIH HHS - R01 HL127895()
  • NIAID NIH HHS - R01 AI125650()
  • NIGMS NIH HHS - R01 GM075141()
  • NINDS NIH HHS - R01 NS075839()

Landscape of histone modifications in a sponge reveals the origin of animal cis-regulatory complexity.

  • Gaiti F
  • Elife
  • 2017 Apr 11

Literature context:


Abstract:

Combinatorial patterns of histone modifications regulate developmental and cell type-specific gene expression and underpin animal complexity, but it is unclear when this regulatory system evolved. By analysing histone modifications in a morphologically-simple, early branching animal, the sponge Amphimedonqueenslandica, we show that the regulatory landscape used by complex bilaterians was already in place at the dawn of animal multicellularity. This includes distal enhancers, repressive chromatin and transcriptional units marked by H3K4me3 that vary with levels of developmental regulation. Strikingly, Amphimedon enhancers are enriched in metazoan-specific microsyntenic units, suggesting that their genomic location is extremely ancient and likely to place constraints on the evolution of surrounding genes. These results suggest that the regulatory foundation for spatiotemporal gene expression evolved prior to the divergence of sponges and eumetazoans, and was necessary for the evolution of animal multicellularity.

Derivation of Pluripotent Stem Cells with In Vivo Embryonic and Extraembryonic Potency.

  • Yang Y
  • Cell
  • 2017 Apr 6

Literature context:


Abstract:

Of all known cultured stem cell types, pluripotent stem cells (PSCs) sit atop the landscape of developmental potency and are characterized by their ability to generate all cell types of an adult organism. However, PSCs show limited contribution to the extraembryonic placental tissues in vivo. Here, we show that a chemical cocktail enables the derivation of stem cells with unique functional and molecular features from mice and humans, designated as extended pluripotent stem (EPS) cells, which are capable of chimerizing both embryonic and extraembryonic tissues. Notably, a single mouse EPS cell shows widespread chimeric contribution to both embryonic and extraembryonic lineages in vivo and permits generating single-EPS-cell-derived mice by tetraploid complementation. Furthermore, human EPS cells exhibit interspecies chimeric competency in mouse conceptuses. Our findings constitute a first step toward capturing pluripotent stem cells with extraembryonic developmental potentials in culture and open new avenues for basic and translational research. VIDEO ABSTRACT.

PCGF6-PRC1 suppresses premature differentiation of mouse embryonic stem cells by regulating germ cell-related genes.

  • Endoh M
  • Elife
  • 2017 Mar 17

Literature context:


Abstract:

The ring finger protein PCGF6 (polycomb group ring finger 6) interacts with RING1A/B and E2F6 associated factors to form a non-canonical PRC1 (polycomb repressive complex 1) known as PCGF6-PRC1. Here, we demonstrate that PCGF6-PRC1 plays a role in repressing a subset of PRC1 target genes by recruiting RING1B and mediating downstream mono-ubiquitination of histone H2A. PCGF6-PRC1 bound loci are highly enriched for promoters of germ cell-related genes in mouse embryonic stem cells (ESCs). Conditional ablation of Pcgf6 in ESCs leads to robust de-repression of such germ cell-related genes, in turn affecting cell growth and viability. We also find a role for PCGF6 in pre- and peri-implantation mouse embryonic development. We further show that a heterodimer of the transcription factors MAX and MGA recruits PCGF6 to target loci. PCGF6 thus links sequence specific target recognition by the MAX/MGA complex to PRC1-dependent transcriptional silencing of germ cell-specific genes in pluripotent stem cells.

An Hdac1/Rpd3-Poised Circuit Balances Continual Self-Renewal and Rapid Restriction of Developmental Potential during Asymmetric Stem Cell Division.

  • Janssens DH
  • Dev. Cell
  • 2017 Feb 27

Literature context:


Abstract:

How the developmental potential of differentiating stem cell progeny becomes rapidly and stably restricted following asymmetric stem cell division is unclear. In the fly larval brain, earmuff (erm) uniquely functions to restrict the developmental potential of intermediate neural progenitors (INPs) generated by asymmetrically dividing neural stem cells (neuroblasts). Here we demonstrate that the histone deacetylase Hdac1/Rpd3 functions together with self-renewal transcriptional repressors to maintain the erm immature INP enhancer in an inactive but poised state in neuroblasts. Within 2 hr of immature INP birth, downregulation of repressor activities alleviates Rpd3-mediated repression on the erm enhancer, enabling acetylation of multiple histone proteins and activating Erm expression. Erm restricts the developmental potential in immature INPs by repressing genes encoding neuroblast transcriptional activators. We propose that poising the fast-activating enhancers of master regulators of differentiation through continual histone deacetylation in stem cells enables self-renewal and rapid restriction of developmental potential following asymmetric division.

Funding information:
  • NIGMS NIH HHS - R01 GM092818()
  • NIGMS NIH HHS - R01 GM111694()
  • NIGMS NIH HHS - T32 GM007315()
  • NINDS NIH HHS - R01 NS077914()

Polycomb Repressive Complex 1 Generates Discrete Compacted Domains that Change during Differentiation.

  • Kundu S
  • Mol. Cell
  • 2017 Feb 2

Literature context:


Abstract:

Master regulatory genes require stable silencing by the polycomb group (PcG) to prevent misexpression during differentiation and development. Some PcG proteins covalently modify histones, which contributes to heritable repression. The role for other effects on chromatin structure is less understood. We characterized the organization of PcG target genes in ESCs and neural progenitors using 5C and super-resolution microscopy. The genomic loci of repressed PcG targets formed discrete, small (20-140 Kb) domains of tight interaction that corresponded to locations bound by canonical polycomb repressive complex 1 (PRC1). These domains changed during differentiation as PRC1 binding changed. Their formation depended upon the Polyhomeotic component of canonical PRC1 and occurred independently of PRC1-catalyzed ubiquitylation. PRC1 domains differ from topologically associating domains in size and boundary characteristics. These domains have the potential to play a key role in transmitting epigenetic silencing of PcG targets by linking PRC1 to formation of a repressive higher-order structure.

Funding information:
  • NHGRI NIH HHS - R01 HG003143()
  • NIDDK NIH HHS - P30 DK040561()
  • NIDDK NIH HHS - U54 DK107980()
  • NIGMS NIH HHS - R01 GM043901()
  • NIGMS NIH HHS - R01 GM090278()

Transgenerational programming of longevity through E(z)-mediated histone H3K27 trimethylation in Drosophila.

  • Xia B
  • Aging (Albany NY)
  • 2016 Nov 25

Literature context:


Abstract:

Transgenerational effects on health and development of early-life nutrition have gained increased attention recently. However, the underlying mechanisms of transgenerational transmission are only starting to emerge, with epigenetics as perhaps the most important mechanism. We recently reported the first animal model to study transgenerational programming of longevity after early-life dietary manipulations, enabling investigations to identify underlying epigenetic mechanisms. We report here that post-eclosion dietary manipulation (PDM) with a low-protein (LP) diet upregulates the protein level of E(z), an H3K27 specific methyltransferase, leading to higher levels of H3K27 trimethylation (H3K27me3). This PDM-mediated change in H3K27me3 corresponded with a shortened longevity of F0 flies as well as their F2 offspring. Specific RNAi-mediated post-eclosion knockdown of E(z) or pharmacological inhibition of its enzymatic function with EPZ-6438 in the F0 parents improved longevity while rendering H3K27me3 low across generations. Importantly, addition of EPZ-6438 to the LP diet fully alleviated the longevity-reducing effect of the LP PDM, supporting the increased level of E(z)-dependent H3K27me3 as the primary cause and immediate early-life period as the critical time to program longevity through epigenetic regulation. These observations establish E(z)-mediated H3K27me3 as one epigenetic mechanism underlying nutritional programming of longevity and support the use of EPZ-6438 to extend lifespan.

Epigenetic Activation of WNT5A Drives Glioblastoma Stem Cell Differentiation and Invasive Growth.

  • Hu B
  • Cell
  • 2016 Nov 17

Literature context:


Abstract:

Glioblastoma stem cells (GSCs) are implicated in tumor neovascularization, invasiveness, and therapeutic resistance. To illuminate mechanisms governing these hallmark features, we developed a de novo glioblastoma multiforme (GBM) model derived from immortalized human neural stem/progenitor cells (hNSCs) to enable precise system-level comparisons of pre-malignant and oncogene-induced malignant states of NSCs. Integrated transcriptomic and epigenomic analyses uncovered a PAX6/DLX5 transcriptional program driving WNT5A-mediated GSC differentiation into endothelial-like cells (GdECs). GdECs recruit existing endothelial cells to promote peritumoral satellite lesions, which serve as a niche supporting the growth of invasive glioma cells away from the primary tumor. Clinical data reveal higher WNT5A and GdECs expression in peritumoral and recurrent GBMs relative to matched intratumoral and primary GBMs, respectively, supporting WNT5A-mediated GSC differentiation and invasive growth in disease recurrence. Thus, the PAX6/DLX5-WNT5A axis governs the diffuse spread of glioma cells throughout the brain parenchyma, contributing to the lethality of GBM.

Funding information:
  • NINDS NIH HHS - R56 NS094589(United States)