E-GEOD-54549
Ontology highlight
ABSTRACT:
OTHER RELATED OMICS DATASETS IN: PRJNA237032
PROVIDER: E-GEOD-54549 | ExpressionAtlas | 2019-05-14
REPOSITORIES: ExpressionAtlas
Similar Datasets
Project description:Role of LDB1 in the transition from chromatin looping to transcription activation
| PRJNA237032 | ENA
Project description:The nucleosome is a fundamental unit of chromatin in eukaryotes, and generally prevents the binding of transcription factors to genomic DNA. Pioneer transcription factors overcome the nucleosome barrier, and bind their target DNA sequences in chromatin. OCT4 is a representative pioneer transcription factor that plays a role in stem cell pluripotency. In the present study, we biochemically analyzed the nucleosome binding by OCT4. Crosslinking mass spectrometry showed that OCT4 binds the nucleosome.
2020-05-13 | PXD019160 | JPOST Repository
Project description:A conspicuous feature of early animal development is the lack of transcription from the embryonic genome, and it typically takes several hours to several days (depending on the species) until widespread transcription of the embryonic genome begins. Although this transition is ubiquitous, relatively little is known about how the shift from a transcriptionally quiescent to transcriptionally active genome is controlled. We describe here the genome-wide distributions and temporal dynamics of nucleosomes and post-translational histone modifications through the maternal-to-zygotic transition in embryos of the pomace fly Drosophila melanogaster. At mitotic cycle 8, when few zygotic genes are being transcribed, embryonic chromatin is in a relatively simple state: there are few nucleosome-free regions, undetectable levels of the histone methylation marks characteristic of mature chromatin, and low levels of histone acetylation at a relatively small number of loci. Histone acetylation increases by cycle 12, but it is not until cycle 14 that nucleosome-free regions and domains of histone methylation become widespread. Early histone acetylation is strongly associated with regions that we have previously shown are bound in early embryos by the maternally deposited transcription factor Zelda. Most of these Zelda-bound regions are destined to be enhancers or promoters active during mitotic cycle 14, and our data demonstrate that they are biochemically distinct long before they become active, raising the possibility that Zelda triggers a cascade of events, including the accumulation of specific histone modifications, that plays a role in the subsequent activation of these sequences. Many of these Zelda-associated active regions occur in larger domains that we find strongly enriched for histone marks characteristic of Polycomb-mediated repression, suggesting a dynamic balance between Zelda activation and Polycomb repression. Collectively, these data paint a complex picture of a genome in transition from a quiescent to an active state, and highlight the role of Zelda in mediating this transition. We performed genome-wide mapping of histone H3 and 9 types of histone modifications, including H4K5ac, H4K8ac, H3K4me1, H3K4me3, H3K27me3, H3K36me3, H3K9ac, H3K18ac, and H3K27ac by ChIP-seq, in hand-sorted wild-type Drosophila melanogaster embryos at 4 different development time points corresponding to mitotic cycle 7-9, 11-13, 14a-b, and 14c-d, respectively. We also carried out ChIP-seq experiments in zelda mutant embryos after showing that the deposition of histone marks in early embryos strongly correlated with the binding of Zelda in wild-type embryos.
2014-10-16 | E-GEOD-58935 | biostudies-arrayexpress
Project description:The earliest stages of development in most metazoans are driven by maternally deposited proteins and mRNAs, with widespread transcriptional activation of the zygotic genome occurring hours after fertilization, at a period known as the maternal-to-zygotic transition (MZT). In Drosophila, the MZT is preceded by the transcription of a small number of genes that initiate sex determination, patterning and other essential developmental processes. The zinc-finger transcription factor Zelda (ZLD) plays a key role in the transcriptional activation of these earliest-expressed genes. To better understand the mechanisms of ZLD activation and the range of its targets, we used chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq) to map regions bound by ZLD prior to (mitotic cycles 8 and 9), during (mitotic cycles 13 and early 14) and after (late mitotic cycle 14) the MZT. Although only a handful of genes are transcribed prior to mitotic cycle 10, we identified thousands of regions bound by ZLD in cycle 8-9 embryos, most of which remain bound through mitotic cycle 14. As expected, these ZLD-bound regions include the promoters and enhancers of the small subset of genes transcribed at this early stage. However we also observed ZLD bound at cycle 8-9 to the promoters of a large fraction of the several thousand genes whose first transcription does not occur until roughly an hour and four mitotic cycles later. These early ZLD-bound regions include virtually all of the thousands of known and presumed enhancers bound at cycle 14 by the transcription factors that regulate patterned gene activation during the MZT. The association between early ZLD binding and MZT activity is so strong that ZLD binding alone can be used to identify active promoters and regulatory sequences with high specificity and selectivity. This strong early association of ZLD with regions not active until the MZT suggests that ZLD is not only required for the earliest wave of transcription, but also plays a major role in activating the genome at the MZT. Genome-wide mapping of Zelda in wild-type Drosophila melanogaster embryos prior (mitotic cycles 8-9), during (cycles 13-14), and after (late cycle 14) maternal-to-zygotic transition
2011-07-18 | E-GEOD-30757 | biostudies-arrayexpress
Project description:We studied the extent of chromatin remodeling in an in-vitro model of the epithelial-mesenchymal transition (EMT). EMT is induced in spheroid cultures (3D) using simultaneously two cytokines: TGFbeta and TNFalpha. The epithelial-mesenchymal transition (EMT) is a cellular de-differentiation process that has been implicated in cancer progression and metastasis. Increasing evidence suggests that EMT is regulated and established by epigenetic reprogramming, however a systems-level mechanism describing how chromatin remodeling contributes to the phenotypic switch is not known. We have generated genome-wide maps of 18 histone modifications/variants and variants in both the epithelial and mesenchymal states and quantified patterns of epigenetic changes at gene and enhancer loci. Clusters of these patterns reveal that EMT-related genes and their proximal enhancers are regulated through coordinated patterns of chromatin activation and repression at both gene and enhancer loci. At the cellular level, the remodeling of gene loci translates into a modular protein interaction network that recapitulates EMT-related signaling. Moreover, differentially activated or repressed enhancers are associated with two non-overlapping sets of transcription factors. We propose a chromatin-mediated regulatory feedback loop model where the NFkappaB and AP-1 transcription factors (TFs) bind activated enhancers, that regulate EMT-related genes, which in turn activate signaling pathways upstream of these TFs.
2013-09-12 | E-GEOD-42374 | biostudies-arrayexpress
Project description:Transcriptionally silent heterochromatin preferentially localizes at the nuclear periphery, but, despite this, certain budding yeast genes relocate to the nuclear periphery following gene activation, implicating the nuclear envelope in both transcriptional activation and silencing. It is unclear how these distinct chromatin domains are established, maintained and distinguished from one another at the nuclear envelope. Here we report that nuclear pore complexes (NPCs) facilitate the transition between chromatin states by providing a platform to which chromatin-remodeling and chromatin-modifying complexes bind. In particular, we show that the RSC chromatin-remodeling complex associates with NPCs and that the nucleoporin Nup170p nucleates heterochromatin formation at telomeres through recruitment of Sir4p. Deletion of NUP170 altered subtelomeric chromatin structure, reduced SIR complex binding at telomeres, impaired telomeric silencing and abated telomere tethering. These results support a model in which telomeric heterochromatin formation occurs through telomere-NPC interactions that both promote Sir4p binding at telomeres and permit chromatin-remodeling complexes to mediate the transition between chromatin states. Examination of genome-wide nucleosome positions in WT and nup170∆ cells via next-generation sequencing of mononucleosomal DNA.
2013-02-28 | E-GEOD-36792 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below. Repetitive sequences such as telomeres, centromeres, and retrotransposons are packed in permanently-condensed and transcriptionally-silenced heterochromatin, whose maintenance is critical for the genome stability. We have recently found that mouse ES cells occasionally go through a unique cell state marked by the transient expression of Zscan4, which plays a key role in long-term genome stability. Here we report our unexpected and counterintuitive finding that the Zscan4+ state is accompanied by a Zscan4-mediated rapid activation and repression of heterochromatin: the burst of transcription from heterochromatin coincided with its transient histone hyperacetylation and DNA demethylation, the clustering of pericentromeric heterochromatin in the perinucleolar region, and the accumulation of chromatin remodeling complexes for both activation (HATs, SWI/SNF) and repression (HDACs, LSD1/KDM1A, NuRD) on heterochromatin. Overall, these findings suggest that ES cells maintain their extraordinary genome stability and immortality by transiently taking extreme measures – a usually forbidden transition to the activated state of heterochromatin. Refer to individual Series
2015-09-10 | E-GEOD-51682 | biostudies-arrayexpress
Project description:The exit from pluripotency or pluripotent-somatic transition (PST) landmarks an event of mammalian development, and is also a representative cell-fate transition model, but remains largely unresolved. Recently, we reported construction of robust JUN-induced PST completed in one cell cycle and whose dominant regulator SS18/BAFs (Brg1/Brahma-associated factors). However, the transition process in the chromatin architecture and the roles played by BAF are still unknown. Here we report the dynamic changes of chromatin accessibility during JUN-induced PST. Meanwhile, SS18/BAFs mediates PST process by relocating from pluripotent loci to AP-1 associated ones and once compromised, JUN fails to open chromatin and PST will be delayed. Furthermore, we show that the relocation of SS18/BAF partially relays on histone modification H3K27ac, instead of JUN-centric protein-protein interaction. These results reveal the orchestration of master transcription factor, epigenetic machine, and histone modification in the cell fate transition.
2021-10-22 | PXD029277 | iProX
Project description:Transcription factors and chromatin modifiers play important roles in programming and reprogramming of cellular states during development. Much is known about the role of these regulators in gene activation, but relatively little is known about the critical process of enhancer silencing during differentiation. Here we show that the H3K4/K9 histone demethylase LSD1 plays an essential role in decommissioning enhancers during differentiation of embryonic stem cells (ESCs). LSD1 occupies enhancers of active genes critical for control of ESC state. However, LSD1 is not essential for maintenance of ESC identity. Instead, ESCs lacking LSD1 activity fail to fully differentiate and ESC-specific enhancers fail to undergo the histone demethylation events associated with differentiation. At enhancers, LSD1 is a component of the NuRD complex, which contains additional subunits that are necessary for ESC differentiation. We propose that the LSD1-NuRD complex decommissions enhancers of the pluripotency program upon differentiation, which is essential for complete shutdown of the ESC gene expression program and the transition to new cell states. This is the ChIP-seq part of the study.
2012-01-03 | E-GEOD-27841 | biostudies-arrayexpress
Project description:The spatial and temporal control of Hox gene transcription is essential for patterning the vertebrate body axis. Although this process involves changes in histone posttranslational modifications, the existence of particular three-dimensional (3D) architectures remained to be assessed in vivo. Using high-resolution chromatin conformation capture methodology, we examined the spatial configuration of Hox clusters in embryonic mouse tissues where different Hox genes are active. When the cluster is transcriptionally inactive, Hox genes associate into a single 3D structure delimited from flanking regions. Once transcription starts, Hox clusters switch to a bimodal 3D organization where newly activated genes progressively cluster into a transcriptionally active compartment. This transition in spatial configurations coincides with the dynamics of chromatin marks, which label the progression of the gene clusters from a negative to a positive transcription status. This spatial compartmentalization may be key to process the collinear activation of these compact gene clusters. Examination of gene expression in 3 cell types. Examination of 2 different histone modifications in 2 cell types.
2011-10-12 | E-GEOD-31570 | biostudies-arrayexpress