To provide further insight about the effects of prolonged Ezh2 inhibition in glioblastoma using preclinical mouse models and doxycycline-inducible shRNAs that mimic the effects of a selective EZH2 inhibitor. We demonstrate that prolonged Ezh2-depletion causes a robust switch in cell fate, including significantly enhanced proliferation and DNA damage repair and activation of part of the pluripotency network, resulting in altered tumor cell identity and tumor progression. Overall design: SVZ derived neural stem cells (NSCs) were isolated from 7 days old p53;Ink4a/Arf;Krasv12;LucR compound conditional mice and cultured in NSC specific serum-free medium supplemented with 20ng/ml of both EGF and bFGF (R&D systems). NSCs were grown adhesion-free for the first passages to eliminate non-sphere-forming cells. Next, cells were grown adherent on poly-L-Ornithine and Laminin plates and three times infected with lentiviral CMV-Cre. These floxed, tumorigenic cells are further referred as glioma initiating cells (GICs). Next, GICs were infected with a tet-inducible, doxycycline-responsive short hairpin construct (FH1-tUTG-shEzh2). After FACS sorting for GFP, GICs were injected intracranial in NOD-SCID mice and treated with or without doxycycline in the drinking water
Prolonged Ezh2 Depletion in Glioblastoma Causes a Robust Switch in Cell Fate Resulting in Tumor Progression.
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View SamplesReporter genes integrated into the genome are a powerful tool to reveal effects of regulatory elements and local chromatin context on gene expression. However, so far such reporter assays have been of low throughput. Here we describe a multiplexing approach for the parallel monitoring of transcriptional activity of thousands of randomly integrated reporters. More than 27,000 distinct reporter integrations in mouse embryonic stem cells, obtained with two different promoters, show ~1,000-fold variation in expression levels. Data analysis indicates that lamina-associated domains act as attenuators of transcription, likely by reducing access of transcription factors to binding sites. Furthermore, chromatin compaction is predictive of reporter activity. We also found evidence for cross-talk between neighboring genes, and estimate that enhancers can influence gene expression on average over ~20 kb. The multiplexed reporter assay is highly flexible in design and can be modified to query a wide range of aspects of gene regulation. Overall design: mRNA profiles of 11 mouse embryonic cell lines each harboring multiple barcoded reporter constructs with mouse PGK promoter integrated at random positions in the genome, single replicate.
Chromatin position effects assayed by thousands of reporters integrated in parallel.
Specimen part, Cell line, Subject
View SamplesIn mammals, sex differentiation of primordial germ cells (PGCs) is determined by extrinsic cues from the environment1. In female PGCs, expression of Stimulated by retinoic acid 8 (Stra8) and meiosis are induced in response to retinoic acid (RA) provided by the mesonephroi2-4. Given the widespread role of RA signaling during development8,9, the molecular mechanism specifying the competence of PGCs to timely express Stra8 and enter meiosis are unknown2,10. Here we identify gene dosage dependent roles in PGC development for Ring1 and Rnf2, two central components of the Polycomb Repressive Complex 1 (PRC1)11,13. Both paralogs are essential for PGC development between day 10.5 and 11.5 of gestation. Rnf2 is subsequently required in female PGCs for maintaining high levels of Oct4 and Nanog expression6, and for preventing premature induction of meiotic gene expression and entry into meiotic prophase. Chemical inhibition of RA signaling partially suppresses precocious Oct4 down-regulation and Stra8 activation in Rnf2-deficient female PGCs. Chromatin immunoprecipitation analyses show that Stra8 is a direct target of PRC1 and PRC2 in PGCs. These data demonstrate the importance of PRC1 gene dosage in PGC development and in coordinating the timing of sex differentiation of female PGCs by antagonizing extrinsic RA signaling.
PRC1 coordinates timing of sexual differentiation of female primordial germ cells.
Sex, Specimen part
View SamplesIn mammals, sex differentiation of primordial germ cells (PGCs) is determined by extrinsic cues from the environment1. In female PGCs, expression of Stimulated by retinoic acid 8 (Stra8) and meiosis are induced in response to retinoic acid (RA) provided by the mesonephroi2-4. Given the widespread role of RA signaling during development8,9, the molecular mechanism specifying the competence of PGCs to timely express Stra8 and enter meiosis are unknown2,10. Here we identify gene dosage dependent roles in PGC development for Ring1 and Rnf2, two central components of the Polycomb Repressive Complex 1 (PRC1)11,13. Both paralogs are essential for PGC development between day 10.5 and 11.5 of gestation. Rnf2 is subsequently required in female PGCs for maintaining high levels of Oct4 and Nanog expression6, and for preventing premature induction of meiotic gene expression and entry into meiotic prophase. Chemical inhibition of RA signaling partially suppresses precocious Oct4 down-regulation and Stra8 activation in Rnf2-deficient female PGCs. Chromatin immunoprecipitation analyses show that Stra8 is a direct target of PRC1 and PRC2 in PGCs. These data demonstrate the importance of PRC1 gene dosage in PGC development and in coordinating the timing of sex differentiation of female PGCs by antagonizing extrinsic RA signaling. Overall design: Gene expression of mouse primordial germ cells was analysed using RNAseq method. Primodial germ cells were purified from embryos carrying Oct4(-delta-PE)-GFP transgene by FACS.
PRC1 coordinates timing of sexual differentiation of female primordial germ cells.
Sex, Specimen part, Subject
View SamplesPolycomb-mediated gene repression plays an important role in adult stem cell maintenance. We knocked out (using the inducible AhCre-LoxP system) Polycomb genes Eed and Ezh2 in the intestine for 6 weeks, after which crypts - the small intestinal stem cell zone - were harvested and RNA sequenced. We found Wnt, Notch and cell cycle pathways to be affected in Eed knockout (KO) but not Ezh2 KO crypts. Direct targets of Eed were determined by comparing this data with ChIP-sequencing. Overall design: Small intestinal crypt mRNA profiles of 6 weeks-induced 12 weeks old Eed KO, Ezh2 KO and WT mice (all triplicates) as well as 10 days-induced Eed KO and WT organoids (duplicates) were generated by RNA sequencing over two runs and using IlluminaHiseq2000 and Hiseq2500.
Deletion of Polycomb Repressive Complex 2 From Mouse Intestine Causes Loss of Stem Cells.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Polycomb function during oogenesis is required for mouse embryonic development.
Specimen part, Treatment
View SamplesIn mammals, totipotent pre-implantation embryos are formed by fusion of highly differentiated oocytes and spermatozoa. Acquisition of totipotency concurs with remodeling of chromatin states of parental genomes (epigenetic reprogramming), changes in maternally contributed transcriptome and proteome, and zygotic genome activation. Genomes of mature germ cells are more proficient in supporting embryonic development than those of somatic cells. It is currently unknown whether transgenerational inheritance of chromatin states present in mature gametes underlies the efficacy of early embryonic development after natural conception. Here, we show that Ring1 and Rnf2, two core components of the Polycomb Repressive Complex 1 (PRC1), serve redundant gene regulatory functions during oogenesis that are required to support embryonic development beyond the two-cell stage. Numerous developmental regulatory genes that are established Polycomb targets in various somatic cell types are de-repressed in Ring1/Rnf2 double mutant (dm) fully grown germinal vesicle (GV) oocytes. Translation of tested aberrant maternal transcripts is, however, delayed until after fertilization. Exchange of maternal pro-nuclei between control and Ring1/Rnf2 maternally dm early zygotes demonstrates an essential role for Ring1 and Rnf2 during oogenesis in defining cytoplasmic and nuclear maternal contributions that are both essential for proper initiation of embryonic development. A large number of genes up-regulated in Ring1/Rnf2 dm GV oocytes harbor PRC2-mediated histone H3 lysine 27 trimethylation (H3K27me3) in spermatozoa and in embryonic stem cells (ESCs), and are repressed during normal oogenesis and early embryogenesis. These data strongly support the model that Polycomb acts in the female and male germline to silence differentiation inducing genes and to program chromatin states, thereby sustaining developmental potential across generations.
Polycomb function during oogenesis is required for mouse embryonic development.
Specimen part
View SamplesSince the discovery of induced pluripotent stem cells there has been intense interest in understanding the mechanisms that allow a somatic cell to be reprogrammed back to a pluripotent state. Several groups have studied the alterations in gene expression that occur as somatic cells modify their genome to that of an embryonic stem cell. Underpinning many of the gene expression changes are modifications to the epigenetic profile of the associated chromatin. We have used a large-scale shRNA screen to identify epigenetic modifiers that act as barriers to reprogramming. We have uncovered an important role for TRIM28 in cells resisting transition between somatic and pluripotent states. TRIM28 achieves this by maintaining the H3K9me3 repressed state and keeping endogenous retroviruses silenced. We propose that knockdown of TRIM28 during reprogramming results in more plastic H3K9me3 domains, dysregulation of genes nearby H3K9me3 marks, and up regulation of endogenous retroviruses, thus facilitating the transition through reprogramming. Overall design: Gene expression profiling using high through put sequencing at day 7 of Oct4, Sox2, Klf4 and cMyc (OSKM) expression in mouse embryonic fibroblasts with or without Trim28 / Setdb1 knockdown
TRIM28 is an Epigenetic Barrier to Induced Pluripotent Stem Cell Reprogramming.
Specimen part, Cell line, Treatment, Subject
View SamplesIn mammals, totipotent pre-implantation embryos are formed by fusion of highly differentiated oocytes and spermatozoa. Acquisition of totipotency concurs with remodeling of chromatin states of parental genomes (epigenetic reprogramming), changes in maternally contributed transcriptome and proteome, and zygotic genome activation. Genomes of mature germ cells are more proficient in supporting embryonic development than those of somatic cells. It is currently unknown whether transgenerational inheritance of chromatin states present in mature gametes underlies the efficacy of early embryonic development after natural conception. Here, we show that Ring1 and Rnf2, two core components of the Polycomb Repressive Complex 1 (PRC1), serve redundant gene regulatory functions during oogenesis that are required to support embryonic development beyond the two-cell stage. Numerous developmental regulatory genes that are established Polycomb targets in various somatic cell types are de-repressed in Ring1/Rnf2 double mutant (dm) fully grown germinal vesicle (GV) oocytes. Translation of tested aberrant maternal transcripts is, however, delayed until after fertilization. Exchange of maternal pro-nuclei between control and Ring1/Rnf2 maternally dm early zygotes demonstrates an essential role for Ring1 and Rnf2 during oogenesis in defining cytoplasmic and nuclear maternal contributions that are both essential for proper initiation of embryonic development. A large number of genes up-regulated in Ring1/Rnf2 dm GV oocytes harbor PRC2-mediated histone H3 lysine 27 trimethylation (H3K27me3) in spermatozoa and in embryonic stem cells (ESCs), and are repressed during normal oogenesis and early embryogenesis. These data strongly support the model that Polycomb acts in the female and male germline to silence differentiation inducing genes and to program chromatin states, thereby sustaining developmental potential across generations.
Polycomb function during oogenesis is required for mouse embryonic development.
Treatment
View SamplesWe wanted to understand the consequences of GSK126-mediated Ezh2 inhibition in an orthotopic model of Kras-driven non-small cell lung cancer (NSCLC). We injected the NSCLC cells with above-mentioned genotype into Nude mice and treated them with GSK126 50mg/kg (daily) or vehicle. As additional control for Ezh2 specificity we treated one tumor with doxycycline that induces shRNA-mediated Ezh2 protein downregulation in those cells. Purified tumour cells were obtained by dissection and FACS sorting based of GFP expression. This experiment contributes the genome-wide response of NSCLC cells to Ezh2 inhibition in vivo. Overall design: We generated mRNA profiles of tumor cells tail vein injected into the lungs of Nude mice by deep sequencing. After FACS purification, RNA extraction and Bioanalyzer analysis, we processed only samples with high quality cellular and RNA profiles. Overall, we compared 10-day GSK126 treated cells (n=4) and up to 30 days GSK126 treated cells (n=3) to Captisol-treated samples (vehicle, n=2), using Illumina Hiseq2000. FACS sorted cells from individual animals were obtained by GFP expression. For H3K27ac and H2AK5ac profiling, we used KP primary tumors generated by injection of NSCLC into the tail vein of nude mice. Mice were sacrificed on the onset of shortness of breath and tissues were resuspended in ChIP lysis buffer.
Ezh2 inhibition in Kras-driven lung cancer amplifies inflammation and associated vulnerabilities.
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