Endogenous retroviruses (ERVs) have provided an evolutionary advantage in the diversification of transcript regulation and are thought to be involved in the establishment of extraembryonic tissues during development. However, silencing of these elements remains critical for the maintenance of genome stability. Here, we define a new chromatin state that is uniquely characterized by the combination of the histone variant H3.3 and H3K9me3, two chromatin ‘marks’ that have previously been considered to belong to fundamentally opposing chromatin states. H3.3/H3K9me3 heterochromatin is fundamentally distinct from ‘canonical’ H3K9me3 heterochromatin that has been under study for decades and this unique functional interplay of a histone variant and a repressive histone mark is crucial for silencing ERVs in ESCs. Our study solidifies the emerging notion that H3.3 is not a histone variant associated exclusively with “active” chromatin and further suggests that its incorporation at unique heterochromatic regions may be central to its function during development and the maintenance of genome stability. Overall design: RNA-seq analysis of three embryonic stem cell lines WT, H3.3 KO1, and H3.3 KO2)
Histone H3.3 is required for endogenous retroviral element silencing in embryonic stem cells.
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View SamplesH3.3 phosphorylation promotes high levels of histone acetylation in mouse embryonic stem cells, which are central to the initiation of new transcription during lineage specification. Overall design: RNA-Seq analysis in mouse embryonic stem cells (Control, H3.3KO, HIRAKO, ATRXKO, DAXXKO) and embryoid bodies at Day 4 of differentiation (Control and H3.3KO).
Phosphorylation of histone H3.3 at serine 31 promotes p300 activity and enhancer acetylation.
Specimen part, Cell line, Subject
View SamplesMature oocyte cytoplasm can reprogram somatic cell nuclei to the pluripotent state through a series of sequential events including protein exchange between the donor nucleus and ooplasm, chromatin remodeling, and pluripotency gene reactivation. Maternal factors that are responsible for this reprogramming process remain largely unidentified. Here, we demonstrate that knockdown of histone variant H3.3 in mouse oocytes results in compromised reprogramming and down-regulation of key pluripotency genes; and this compromised reprogramming both for developmental potentials and transcription of pluripotency genes can be rescued by injecting exogenous H3.3 mRNA, but not H3.2 mRNA into oocytes in somatic cell nuclear transfer (SCNT) embryos. We show that maternal H3.3, and not H3.3 in the donor nucleus, is essential for successful reprogramming of somatic cell nucleus into the pluripotent state. Furthermore, H3.3 is involved in this reprogramming process by remodeling the donor nuclear chromatin through replacement of donor nucleus-derived H3 with de novo synthesized maternal H3.3 protein. Our study shows that H3.3 is a crucial maternal factor for oocyte reprogramming and provides a practical model to directly dissect the oocyte for its reprogramming capacity. Overall design: Transcriptome sequencing of 4-cell NT embryos, Luciferase 4-cell SCNT embryos, 4-cell NT embryos_H3.3KD, 4-cell NT embryos_H3.3KD+H3.3mRNA, H3.3 KD + H3.2 mRNA SCNT embryos
Histone variant H3.3 is an essential maternal factor for oocyte reprogramming.
No sample metadata fields
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
View SamplesH3.3-mediated paternal chromatin remodeling is essential for the development of preimplantation embryos and the activation of the paternal genome during embryogenesis. Overall design: We collected embryos of WT, mH3.3KD and H3.3-addback at 50h after ICSI (8-cell or 16-cell stage). RNA-seq results confirmed excellent knockdown of both H3.3A and H3.3B mRNAs in mH3.3KD and H3.3-addback embryos.
Histone variant H3.3-mediated chromatin remodeling is essential for paternal genome activation in mouse preimplantation embryos.
Cell line, Subject
View SamplesHira has been implicated in replication-independent chromatin assembly.
Distinct factors control histone variant H3.3 localization at specific genomic regions.
Specimen part
View SamplesPurpose: Recurrent ASXL1 mutations are frequently observed in all spectrums of myeloid malignancies and published data suggests that ASXL1 mutations may be involved in leukemic transformation as a tumor suppressor. Yet the molecular mechanisms of cell desitiny regulated by ASXL1 are to be further delineated. Methods: mRNA profiles of wild-type (WT) and CRISPR/Cas9 induced ASXL1 mutated U937 cell lines were generated by next generation sequencing, using Illumina HiSeq2500. Sequence reads were trimmed to remove possible adapter sequences and nucleotides with poor quality at the ends. Remaining sequence reads were then aligned to the human reference genome (hg19) using Tophat2. Gene read counts were measured using FeatureCounts and FPKM values were calculated with cufflinks. edgeR was used to identify differentially expressed genes between conditions, and topGO was used for annotation (Alexa, Rahnenfuhrer, and Lengauer, 2006). Sample comparison for differential gene expression was as follows: WTblk and WT1 versus MT2, MT3, MT4, and MT5. Gene enrichment set analysis (GSEA) was conducted with KEGG, Biocarta, and Reactome pathway datasets (Subramanian et al., 2005). Results: ASXL1-mutated cells displayed impaired differentiation capacity. RNA-seq was used to compare transcriptomes of ASXL1-mutated and WT U937 cells. Transcriptom analysis revealed that ASXL1 mutations decreased the expression of genes essential to myeloid differentiation, including CYBB and CLEC5A genes, which manifested in ASXL1-MT U937 cells as perturbed potential of differentiation compared with WT cells. Also, gene set enrichment analysis revealed that ASXL1 mutations masively affected gene sets relating to cell death and survival. Conclusion: By introduction of mutations into genome using the CRISPR/Cas9 system, we established ASXL1-mutated U937 cell lines. Our results indicated that ASXL1 mutations perturbed monocytic/phagocyte differentiation, which is a hallmark of myeloid malignancies, by down regulating genes essential to myeloid differentiation, including CYBB and CLEC5A, also massively affected multiple gene sets involving in cell survival. Overall design: mRNA profiles of wild type (WT) and ASXL1 mutated U937 cell lines were generated by deep sequencing using Illumina HiSeq2500
CRISPR/Cas9-mediated ASXL1 mutations in U937 cells disrupt myeloid differentiation.
Specimen part, Cell line, Subject
View SamplesPurpose: DNA methyltransferase 3A (DNMT3A) mediates de novo DNA methylation. Mutations in DNMT3A are associated with hematological malignancies, most frequently acute myeloid leukemia. DNMT3A mutations are hypothesized to establish a pre-leukemic state, rendering cells vulnerable to secondary oncogenic mutations and malignant transformation. However, the mechanisms by which DNMT3A mutations contribute to leukemogenesis are not well-defined. Methods: mRNA profiles of wild-type (WT) and DNMT3A mutated k562 cell lines were generated by deep sequencing, using Illumina HiSeq2500. Sequence reads were trimmed to remove possible adapter sequences and nucleotides with poor quality at the ends. Remaining sequence reads were then aligned to the human reference genome (hg19) using Tophat2. Gene read counts were measured using FeatureCounts and FPKM values were calculated with cufflinks. edgeR was used to identify differentially expressed genes between conditions, and topGO was used for annotation (Alexa, Rahnenfuhrer, and Lengauer, 2006). Sample comparison for differential gene expression was as follows: WTblk and WT1 versus MT2, MT3, MT4, and MT5. Gene enrichment set analysis (GSEA) was conducted with KEGG, Biocarta, and Reactome pathway datasets (Subramanian et al., 2005). Results: DNMT3A-mutated cells displayed impaired differentiation capacity. RNA-seq was used to compare transcriptomes of DNMT3A-mutated and WT cells; DNMT3A ablation resulted in downregulation of genes involved in spliceosome function, causing dysfunction of RNA splicing. Unexpectedly, we observed DNMT3A-mutated cells to exhibit marked genomic instability and an impaired DNA damage response compared to WT. Conclusions: CRISPR/Cas9-mediated DNMT3A-mutated K562 cells may be used to model effects of DNMT3A mutations in human cells. Our findings implicate aberrant splicing and induction of genomic instability as potential mechanisms by which DNMT3A mutations might predispose to malignancy. Overall design: mRNA profiles of wild type (WT) and DNMT3A mutated K562 cell lines were generated by deep sequencing using Illumina HiSeq2500
Abnormal RNA splicing and genomic instability after induction of DNMT3A mutations by CRISPR/Cas9 gene editing.
Specimen part, Cell line, Subject
View Samplesto investigate the RA regulated genes in 2 dpp thy1+ gonocytes
Expression of stimulated by retinoic acid gene 8 (Stra8) and maturation of murine gonocytes and spermatogonia induced by retinoic acid in vitro.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Brucella melitensis, B. neotomae and B. ovis elicit common and distinctive macrophage defense transcriptional responses.
Specimen part
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