MLL-fusion proteins are potent inducers of cancer in hematopoietic cells, where they are known to cause changes in global gene expression. How MLL-fusion proteins interact with the genome has not been established, so we have limited understanding of the pathway by which these proteins generate aberrant gene expression programs. Here we describe how the MLL-AF4 protein occupies the genome in human leukemia cells and its striking effects on chromatin states. We find that the MLL-AF4 fusion protein selectively occupies regions of the genome that contain developmental regulatory genes important for hematopoietic stem cell identity and self-renewal. These MLL-AF4 bound regions have grossly altered chromatin structure, with histone modifications catalyzed by Trithorax Group (TrxG) proteins and Dot1 extending across unusually large domains. This indicates that a key feature of MLL-associated leukemogenesis is aberrant targeting of chromatin modifiers to regions of the genome controlling hematopoietic development. Our results define the direct targets of the MLL-fusion protein, reveal the global role of epigenetic misregulation in leukemia, and identify new targets for therapeutic intervention in human cancer.
Aberrant chromatin at genes encoding stem cell regulators in human mixed-lineage leukemia.
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View SamplesPolycomb repressive complex 2 (PRC2) regulates gene expression during lineage specification through trimethylation of lysine 27 on histone H3 (H3K27me3). In Drosophila, polycomb binding sites are dynamic chromatin regions coupled to incorporation of the histone variant H3.3. Here we show in mouse embryonic stem cells (ESCs) that H3.3 is required for proper establishment of H3K27me3 at the promoters of developmentally regulated genes. These promoters show reduced dynamics as determined by deposition of de novo synthesized histones, associated with reduced PRC2 occupancy. H3.3-depleted ESCs show upregulation of extraembryonic trophectoderm, as well as misregulation of other developmental genes upon differentiation. Our data demonstrate the importance of H3.3 incorporation in ESCs and suggest that changes in chromatin dynamics in its absence lead to misregulation of gene expression during differentiation. Moreover, our findings lend support to the emerging notion that H3.3 has multiple functions in distinct genomic locations that are not always correlated with an “active” chromatin state. Overall design: RNA-seq analysis of three embryonic stem cell lines (control, H3.3 KD1, and H3.3 KD2)
Hira-dependent histone H3.3 deposition facilitates PRC2 recruitment at developmental loci in ES cells.
Specimen part, Cell line, Subject
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The H3K27 demethylase Utx regulates somatic and germ cell epigenetic reprogramming.
Specimen part
View SamplesPluripotency can be induced in somatic cells by ectopic expression of defined transcription factors, however the identity of epigenetic regulators driving the progression of cellular reprogramming requires further investigation. Here we uncover a non-redundant role for the JmjC-domain-containing protein histone H3 methylated Lys 27 (H3K27) demethylase Utx, as a critical regulator for the induction, but not for the maintenance, of primed and nave pluripotency in mice and in humans. Utx depletion results in aberrant H3K27me3 repressive chromatin demethylation dynamics, which subsequently hampers the reactivation of pluripotency promoting genes during reprogramming. Remarkably, Utx deficient primordial germ cells (PGCs) display a cell autonomous aberrant epigenetic reprogramming in vivo during their embryonic maturation, resulting in the lack of functional contribution to the germ-line lineage.
The H3K27 demethylase Utx regulates somatic and germ cell epigenetic reprogramming.
Specimen part
View SamplesCystic fibrosis transmembrane conductance regulator (Cftr) knockout mice present the clinical features of low body weight and intestinal disease permitting an assessment of the interrelatedness of these phenotypes in a controlled environment. To identify intestinal alterations which affect body weight in CF mice the histological phenotypes of crypt-villus axis height, goblet cell hyperplasia, and mast cell infiltrate were measured, cardiac blood samples assessed, and gene expression profiling of the ileum was completed for 12 week old (C57BL/6xBALB) F2 Cftrtm1UNC and non-CF mice presenting a range of body weight. Crypt-villus axis height decreased with increasing weight in CF, but not control, mice. Goblet cell hyperplasia and mast cell infiltration in the submucosa and muscularis externa layers of the CF intestine, were identified to be independent of bodyweight. Blood triglyceride levels were found to be significantly lower in CF mice than control mice (p = 3.02 x 10-5) but were not dependent on CF mouse body weight. By expression profiling, genes of DNA replication and lipid metabolism were among those altered in CF mice relative to non-CF controls; and no differences in gene expression were measured between samples from CF mice in the 25th and 75th percentile for weight. This study indicates that the absence of Cftr leads to altered morphology in the CF intestine the extent of which is correlated with body weight in CF mice while CF related changes in blood triglyceride levels and in the intestinal gene expression profile were not dependent on body weight in this model.
Intestinal phenotype of variable-weight cystic fibrosis knockout mice.
Sex
View SamplesHISRainbow mice were used to obtain mosaic ovaries for transcriptome analysis of MII eggs expressing H3.3-eGFP, H3.3R26K-eCFP, or H3.3K27R-mCherry. Results provide comparison of eggs with different genotypes and insight into mechanism of how resting oocytes are selected for ovulation. Overall design: Transcriptome profiling of eggs expressing H3.3-eGFP, H3.3R26K-eCFP, or H3.3K27R-mCherry by deep sequencing in duplicates.
Genetic mosaics and time-lapse imaging identify functions of histone H3.3 residues in mouse oocytes and embryos.
Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Vitamin C supplementation modulates gene expression in peripheral blood mononuclear cells specifically upon an inflammatory stimulus: a pilot study in healthy subjects.
Specimen part
View SamplesThe epigenetic changes of the chromatin represent an attractive molecular substrate for adaptation to the environment. We examined here the role of CBP, a histone acetyltransferase involved in mental retardation, in the genesis and maintenance of long-lasting systemic and behavioral adaptations to environmental enrichment (EE). Morphological and behavioral analyses demonstrated that EE ameliorates deficits associated to CBP-deficiency. However, CBP-deficient mice also showed a strong defect in environment-induced neurogenesis and impaired EE-enhanced spatial navigation and patter separation ability. These defects correlated with an attenuation of the transcriptional program induced in response to EE and with deficits in histone acetylation at the promoters of EE-regulated, neurogenesis-related genes. Additional experiments in CBP restricted and inducible knockout mice indicated that environment-induced adult neurogenesis is extrinsically regulated by CBP function in mature granule cells. Overall, our experiments demonstrate that the environment alters gene expression by impinging on activities involved in modifying the epigenome and identify CBP-dependent transcriptional neuroadaptation as an important mediator of EE-induced benefits, a finding with important implications for mental retardation therapeutics.
CBP is required for environmental enrichment-induced neurogenesis and cognitive enhancement.
Sex, Age, Specimen part
View SamplesA role of vitamin C (ascorbic acid) as an antioxidant molecule has been recognized, largely based on in vitro studies. However, more recently, the concept of antioxidant molecule has been reconsidered and its biological function is no longer considered to be simply due to its ability to act as electron donors, rather, it appears to act by modulating signaling and gene expression.
Vitamin C supplementation modulates gene expression in peripheral blood mononuclear cells specifically upon an inflammatory stimulus: a pilot study in healthy subjects.
Specimen part
View SamplesTo identify gene(s) that are modified in their relative expression levels in the Potocki-Lupski Syndrome mouse model and map to the rearranged region, i.e. possible candidate genes at the source of the PTLS-like phenotypes shown by the PTLS mouse, we comp
Abnormal social behaviors and altered gene expression rates in a mouse model for Potocki-Lupski syndrome.
No sample metadata fields
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