Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA269282 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:DNase I hypersensitive sites (DHSs) are a hallmark of chromatin regions containing regulatory DNA such as enhancers and promoters; however, the factors affecting the establishment and maintenance of these sites are not fully understood. We now show that HMGN1 and HMGN2, nucleosome-binding proteins that are ubiquitously expressed in vertebrate cells, maintain the DHS landscape of mouse embryonic fibroblasts (MEFs) synergistically. Loss of one of these HMGN variants led to a compensatory increase of binding of remaining variant. Genome wide mapping of the DHSs in Hmgn1-/-, Hmgn2-/- and Hmgn1-/-n2-/- MEFs reveals that loss of both, but not a single HMGN variant, leads to significant remodeling of the DHS landscape, especially at enhancer regions marked by H3K4me1 and H3K27ac. Loss of HMGN variants affects the induced expression of stress responsive genes in MEFs, the transcription profiles of several mouse tissues, and leads to altered phenotypes that are not seen in mice lacking only one variant. We conclude that the compensatory binding of HMGN variants to chromatin maintains the DHS landscape and the transcription fidelity necessary to retain wild type phenotypes. Our studies provide insights into mechanisms that maintain regulatory sites in chromatin and into functional compensation among nucleosome binding architectural proteins.
2017-10-01 | GSE66442 | GEO
Project description:Genome-wide DNase hypersensitive sites during osteoclastogenesis
| PRJNA235294 | ENA
Project description:Adipogenesis is tightly controlled by a complex network of transcription factors acting at different stages of differentiation. Peroxisome proliferator-activated receptor gamma (PPAR gamma) and CCAAT/enhancer binding protein (C/EBP) family members are key regulators of this process. We have employed DNase I hypersensitive site analysis to investigate the genome-wide changes in chromatin structure that accompany the binding of adipogenic transcription factors. These analyses revealed a dramatic and dynamic modulation of the chromatin landscape during the first hours of adipocyte differentiation that coincides with cooperative binding of multiple early transcription factors (including glucocorticoid receptor, retinoid X receptor, Stat5a, C/EBPbeta and -delta) to transcription factor 'hotspots'. Our results demonstrate that C/EBPbeta marks a large number of these transcription factor 'hotspots' prior to induction of differentiation and chromatin remodeling and is required for their establishment. Furthermore, a subset of early remodeled C/EBP binding sites persists throughout differentiation and is later occupied by PPAR gamma , indicating that early C/EBP family members, in addition to their well established role in activation of PPAR gamma transcription, may act as pioneering factors for PPAR gamma binding. DNase I hypersensitive chromatin regions and transcription factor binding sites were identified at various time points of 3T3-L1 differentiation using DHS-seq and ChIP-seq, respectively.
2011-03-22 | E-GEOD-27826 | biostudies-arrayexpress
Project description:Identifying cis-regulatory elements is important to understand how human pancreatic islets modulate gene expression in physiologic or pathophysiologic (e.g., diabetic) conditions. We conducted genome-wide analysis of DNase I hypersensitive sites, histone H3 lysine methylation marks (K4me1, K4me3, K79me2), and CCCTC factor (CTCF) binding in human islets. This identified ~18,000 putative promoters (several hundred novel and islet-active). Surprisingly, active promoter marks were absent at genes encoding islet-specific hormones, suggesting a distinct regulatory mechanism. Of 34,039 distal (non-promoter) regulatory elements, 47% are islet-unique and 22% are CTCF-bound. These findings present a global snapshot of the human islet epigenome and should provide functional context for non-coding variants emerging from genetic studies of T2D and other pancreatic islet disorders. Three different islet samples were tested for DNase I hypersensitivity by DNase-Seq. Five different primary pancreatic islet samples were evaluated for several chromatin modifications (H3K4me3, H3K4me1, H3K79me2) by ChIP-seq. One islet sample was evaluated for CTCF binding via ChIP-seq, All ChIP-seq samples have both non-specific IP (GFP) and input DNA controls.
2010-11-02 | E-GEOD-23784 | biostudies-arrayexpress
Project description:DNase I hypersensitive sites in two tissues of rice
| PRJNA142219 | ENA
Project description:Chromatin accessibility captures the binding status of protein factors to chromosomes in vivo, and has been considered a highly informative proxy for functional protein-DNA interactions. Existing DNase I and Tn5 transposase based assays generally require tens of thousands to millions of fresh cells. Applying Tn5 tagmentation to single cells yields very sparse maps. Here we present a transposome hypersensitive sites sequencing assay (THS-seq) for highly sensitive characterizations of chromatin accessibility.
2016-01-09 | GSE72089 | GEO
Project description:Clarification of the mechanisms underlying osteoclast differentiation enable us to understand the physiology of bone metabolism as well as the pathophysiology of bone diseases, such as osteoporosis. Recently, it has been reported that epigenetics can determine the cell fate and regulate cell type specific gene expression. However, little is known about epigenetics during osteoclastogenesis. To reveal a part of epigenetics, especially focused on chromatin dynamics, during early osteoclastogenesis and identify novel transcription factors involved in osteoclastogenesis, we investigated genome-wide analysis of open chromatin during receptor activator of nuclear factor-M-NM-:B ligand (RANKL)-induced osteoclastogenesis using DNase I hypersensitive sites sequencing (DNase-seq). DNase-seq was performed using the extracted nuclei obtained from RAW264 cells treated with or without RANKL for 24 hours, followed by several bioinformatic analyses. DNase I hypersensitive sites (DHSs) during RANKL-induced osteoclastogenesis were dynamically changed and accumulated in promoter regions, although the distributions of DHSs among cis-regulatory DNA regions were identical regardless of RANKL stimulation. Motif discoveries from DHSs successfully identified well-known osteoclastogenic transcription factors such as Jun, CREB1, FOS, ATF2 and ATF4, but also novel transcription factors for osteoclastogenesis such as Zscan10, Atf1 Nrf1 and Srebf2. siRNA knockdown of these identified novel transcription factors impaired osteoclastogenesis. Taken together, DNase-seq can be a useful tool for comprehension of epigenetics, especially chromatin dynamics during osteoclastogenesis and for identification of novel transcription factors involved in osteoclastogenesis. This study may reveal underlying mechanisms that determine cell-type specific differentiation of bone cells and may lead to investigate novel therapeutic targets for osteoporosis. Examination of genome-wide DNase Hypersensitive Sites in differentiated and undifferentiated RAW264 cells.
2014-11-05 | E-GEOD-54139 | biostudies-arrayexpress
Project description:Nucleosome structure and positioning play pivotal roles in gene regulation, DNA repair and other essential processes in eukaryotic cells. Nucleosomal DNA is thought to be uniformly inaccessible to DNA binding and processing factors, such as MNase. Here, we show, however, that nucleosome accessibility and sensitivity to MNase varies. Digestion of Drosophila chromatin with two distinct concentrations of MNase revealed two types of nucleosomes: sensitive and resistant. MNase-resistant nucleosome arrays are less accessible to low concentrations of MNase, whereas MNase-sensitive arrays are degraded by high concentrations. MNase-resistant nucleosomes assemble on sequences depleted of A/T and enriched in G/C containing dinucleotides. In contrast, MNase-sensitive nucleosomes form on A/T rich sequences represented by transcription start and termination sites, enhancers and DNase hypersensitive sites. Lowering of cell growth temperature to ~10°C stabilizes MNase-sensitive nucleosomes suggesting that variations in sensitivity to MNase are related to either thermal fluctuations in chromatin fiber or the activity of enzymatic machinery. In the vicinity of active genes and DNase hypersensitive sites nucleosomes are organized into synchronous, periodic arrays. These patterns are likely to be caused by “phasing” nucleosomes off a potential barrier formed by DNA-bound factors and we provide an extensive biophysical framework to explain this effect. RNA-seq S2 cells Drosophila melanogaster
2015-09-17 | E-GEOD-69335 | biostudies-arrayexpress
Project description:Nucleosome structure and positioning play pivotal roles in gene regulation, DNA repair and other essential processes in eukaryotic cells. Nucleosomal DNA is thought to be uniformly inaccessible to DNA binding and processing factors, such as MNase. Here, we show, however, that nucleosome accessibility and sensitivity to MNase varies. Digestion of Drosophila chromatin with two distinct concentrations of MNase revealed two types of nucleosomes: sensitive and resistant. MNase-resistant nucleosome arrays are less accessible to low concentrations of MNase, whereas MNase-sensitive arrays are degraded by high concentrations. MNase-resistant nucleosomes assemble on sequences depleted of A/T and enriched in G/C containing dinucleotides. In contrast, MNase-sensitive nucleosomes form on A/T rich sequences represented by transcription start and termination sites, enhancers and DNase hypersensitive sites. Lowering of cell growth temperature to ~10°C stabilizes MNase-sensitive nucleosomes suggesting that variations in sensitivity to MNase are related to either thermal fluctuations in chromatin fiber or the activity of enzymatic machinery. In the vicinity of active genes and DNase hypersensitive sites nucleosomes are organized into synchronous, periodic arrays. These patterns are likely to be caused by “phasing” nucleosomes off a potential barrier formed by DNA-bound factors and we provide an extensive biophysical framework to explain this effect. Mnase-seq, Mnase-ChIP-seq of Drosophila melanogaster embryo and S2 cells chromatin
2015-09-17 | E-GEOD-69177 | biostudies-arrayexpress
Project description:While it is well established that variation in gene expression levels can be influenced by single nucleotide polymorphisms (SNPs), little is known about the regulatory mechanisms by which this occurs. To address this gap, we used DNaseI sequencing to measure genome-wide chromatin accessibility in 70 Yoruba lymphoblastoid cell lines (LCLs), for which genome-wide genotypes and estimates of gene expression levels based on RNA-sequencing are also available. We obtained a total of 2.8 billion uniquely mapped DNase-seq reads, which allowed us to produce genome-wide maps of chromatin accessibility for each individual. We identified 7,759 locations at which DNase-seq read depth correlates significantly with variation at a nearby SNP or indel (FDR=10%). We call such variants 'chromatin accessibility Quantitative Trait Loci' (or caQTLs). Most caQTLs lie within or very near the target DNaseI hypersensitive sites, and they are strongly enriched within inferred transcription factor binding sites. We find that a substantial fraction (14%) of caQTLs are also significantly associated with variation in the expression levels of nearby genes (namely, these loci are also classified as eQTLs), suggesting that changes in chromatin accessibility or transcription factor binding frequently lead to gene expression changes. Conversely, 12% of eQTL SNPs are also classified as caQTLs and, accounting for incomplete power, we estimate that the true fraction may be as high as 41%. Our observations indicate that caQTLs are abundant in the human genome, and are likely to be significant contributors to phenotypic variation. DNaseI-Seq on 70 YRI Hapmap cell lines. Each individual sequenced on several lanes of a flow cell on the Illumina Genome Analyzer II
2012-01-26 | E-GEOD-31388 | biostudies-arrayexpress