ChIP-seq analysis of histone H3K4me3, H3K27Ac and RNA polymerase II (RNApol II) in HuH-7 cells.
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE109575 | GEO | 2018/01/25
REPOSITORIES: GEO
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Project description:ChIP-seq analysis of histone H3K4me3, H3K27Ac and RNA polymerase II (RNApol II) in HuH-7 cells.
| PRJNA431417 | ENA
Project description:Adaptation of the ChIP-on-chip protocol, to calculate genomic transcription rates in S. cerevisiae. Keywords: ChIP-chip There are 3 different experimental conditions: -Yeast cell growing exponentially in YPD. -Yeast cell stopped after 2 h of changing them to YPGal. -Yeast cell growing exponentially after 14.5 h of changing them to YPGal. We have used 3 different IP protocols: -total RNApol II using a Myc tagged RNApol (RPB1-Myc) -RNApol II CTD using the Ab 8WG16 (Covance) -RNApol II CTD Phosphorilated on Ser5 (David Bentley\'s lab) There are 3 independent biological replicates of each experiment.
2010-06-24 | E-GEOD-14060 | biostudies-arrayexpress
Project description:The diversity and complexity of the cancer transcriptome hold the potential to yield tumor-specific transcripts (TSTs) in cancer. We report a novel LIN28B variant, LIN28B-TST, which is specifically expressed in hepatocellular carcinoma (HCC) and many other cancer types. LIN28B-TST initiates from a de novo alternative transcription initiation site. We found that LIN28B-TST was expressed in HuH-7 HCC cells and NCI-H1299 lung cancer cells, while wild-type LIN28B (LIN28B-WT) was expressed in HEK-293T human embryo kidney cells.
2018-01-24 | GSE109528 | GEO
Project description:Background. Recent epigenomic studies have shown that the length of a DNA region covered by an epigenetic mark is not just a byproduct of the assaying technologies and has functional implications for that locus. For example, expanded regions of DNA sequences that are marked by enhancer-specific histone modifications, such as acetylation of histone H3 lysine 27 (H3K27ac) domains coincide with cell-specific enhancers, known as super or stretch enhancers. Similarly, promoters of genes critical for cell-specific functions are marked by expanded H3K4me3 domains in the cognate cell type, and these can span DNA regions from 4-5kb up to 40-50kb in length. These expanded H3K4me3 domains are known as buffer domains or super promoters. Methods. To ask what correlates with-and potentially regulates-the length of loci marked with these two important histone marks, H3K4me3 and H3K27ac, we built Random Forest regression models. With these models, we computationally identified genomic and epigenomic patterns that are predictive for the length of these marks in seven ENCODE cell lines. Results. We found that certain epigenetic marks and transcription factors explain the variability of the length of H3K4me3 and H3K27ac marks across different cell types, which implies that the lengths of these two epigenetic marks are tightly regulated in a given cell type. Our source code for the regression models and data can be found at our GitHub page: https://github.com/zubekj/broad_peaks. Discussion. Our Random Forest based regression models enabled us to estimate the individual contribution of different epigenetic marks and protein binding patterns to the length of H3K4me3 and H3K27ac deposition patterns, therefore potentially revealing genomic signatures at cell specific regulatory elements.
| S-EPMC4793332 | biostudies-literature
Project description:Trimethylation of histone H3 lysine 4 (H3K4me3) is associated with transcriptional start sites and proposed to regulate transcription initiation. However, redundant functions of the H3K4 SET1/COMPASS methyltransferase complexes complicate elucidation of the specific role of H3K4me3 in transcriptional regulation. Here, by using mouse embryonic stem cells (mESCs) as a model system, we show that acute ablation of shared subunits of the SET1/COMPASS complexes leads to complete loss of all H3K4 methylation. H3K4me3 turnover occurs more rapidly than H3K4me1 and H3K4me2 and is dependent on KDM5 demethylases. Surprisingly, acute loss of H3K4me3 does not have detectable effects on transcriptional initiation but leads to a widespread decrease in transcriptional output, an increase in RNA polymerase II (RNAPII) pausing and slower elongation. Notably, we show that H3K4me3 is required for the recruitment of the Integrator Complex Subunit 11 (INTS11), which is essential for the eviction of paused RNAPII and transcriptional elongation. Thus, our study demonstrates a distinct role for H3K4me3 in transcriptional pause-release and elongation rather than transcriptional initiation.
2023-02-10 | PXD039176 | Pride
Project description:BACKGROUND: Histone modification is an epigenetic mechanism that influences gene regulation in eukaryotes. In particular, histone modifications in CpG islands (CGIs) are associated with different chromatin states and with transcription activity. Changes in gene expression play a crucial role in adaptation and evolution. RESULTS: In this paper, we have studied, using a computational biology approach, the relationship between histone modifications in CGIs and selective pressure in Homo sapiens. We considered three histone modifications: histone H3 lysine 4 trimethylation (H3K4me3), histone H3 lysine 27 acetylation (H3K27ac) and histone H3 lysine 36 trimethylation (H3K36me3), and we used the publicly available genomic-scale histone modification data of thirteen human cell lines. To define regions under selective pressure, we used three distinct signatures that mark selective events from different evolutionary periods. We found that CGIs under selective pressure showed significant enrichments for histone modifications. CONCLUSION: Our result suggests that, CGIs that have undergone selective events are characterized by epigenetic signatures, in particular, histone modifications that are distinct from CGIs with no evidence of selection.
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Project description:The Pol II elongation rate influences poly(A) site selection, with slow and fast Pol II derivatives causing upstream and downstream shifts, respectively, in poly(A) site utilization. In yeast, depletion of either of the histone chaperones FACT or Spt6 causes an upstream shift of poly(A) site use that strongly resembles the poly(A) profiles of slow Pol II mutant strains. Like slow Pol II mutant strains, Spt6- and FACT-depleted cells exhibit processivity defects, indicating that both Spt6 and FACT stimulate the Pol II elongation rate. Poly(A) profiles of some genes show atypical downstream shifts; this subset of genes overlaps well for FACT- or Spt6- depleted strains, but it is different from the atypical genes in Pol II speed mutant strains. In contrast, depletion of histone H3 or H4 causes a downstream shift of poly(A) sites for most genes, indicating that nucleosomes inhibit the Pol II elongation rate in vivo. Thus, chromatin-based control of the Pol II elongation rate is a potential mechanism, distinct from direct effects on the cleavage/polyadenylation machinery, to regulate alternative polyadenylation in response to genetic or environmental changes.
2024-07-08 | GSE262747 | GEO
Project description:Neurons are central to lifelong learning and memory, but ageing disrupts their morphology and function, leading to cognitive decline. Although epigenetic mechanisms are known to play crucial roles in learning and memory, neuron-specific genome-wide epigenetic maps into old age remain scarce, often being limited to whole-brain homogenates and confounded by glial cells. Here, we mapped H3K4me3, H3K27ac, and H3K27me3 in mouse neurons across their lifespan. This revealed stable H3K4me3 and global losses of H3K27ac and H3K27me3 into old age. We observed patterns of synaptic function gene deactivation, regulated through the loss of the active mark H3K27ac, but not H3K4me3. Alongside this, embryonic development loci lost repressive H3K27me3 in old age. This suggests a loss of a highly refined neuronal cellular identity linked to global chromatin reconfiguration. Collectively, these findings indicate a key role for epigenetic regulation in neurons that is inextricably linked with ageing.
| S-EPMC11353134 | biostudies-literature
Project description:RNA polymerase II (Pol II) pauses downstream of the transcription initiation site before beginning productive elongation. This pause is a key component of metazoan gene expression regulation. Some promoters have a strong disposition for Pol II pausing and often mediate faster, more synchronous changes in expression. This requires multiple rounds of transcription and thus cannot rely solely on pause release. But it is unclear how pausing affects the initiation of new transcripts during consecutive rounds of transcription. Using our recently developed ChIP-nexus method, we find that Pol II pausing inhibits new initiation. We propose that paused Pol II helps prevent new initiation between transcription bursts, which may reduce noise.
2017-04-17 | GSE85741 | GEO
Project description:Transcription activation involves RNA polymerase II (Pol II) recruitment and release from the promoter into productive elongation, but how specific chromatin regulators control these steps is not fully understood. Here we identify a novel activity of the co-regulator and histone acetyltransferase p300/CBP in positioning promoter-proximal paused Pol II. We find that CBP inhibition impedes transcription through the +1 nucleosome, causing âdribblingâ of Pol II from the canonical pause site genome-wide. We further discovered that promoters strongly occupied by Drosophila CBP and GAGA-factor have high levels of paused Pol II, a unique chromatin signature and strong expression regardless of cell type. Interestingly, CBP activity is rate-limiting for Pol II recruitment to these highly-paused promoters but for transit into elongation at other genes. Thus, we uncover a key role for CBP during transcription in directly controlling different rate-limiting steps depending on promoter features. Examination of transcriptional regulation with and without CBP inhibition for 10 minutes in Drosophila S2 cells. Two biological replicates for each condition.
2016-08-01 | E-GEOD-81649 | biostudies-arrayexpress