ISDH-seq: a robust methodology for profiling and characterization of open chromatin
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ABSTRACT:
ORGANISM(S): Oryza sativa
PROVIDER: GSE235900 | GEO | 2025/05/01
REPOSITORIES: GEO
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Project description:Mammalian chromatin is dynamic and contains structural information that leads to transcriptional regulation of genes by recruiting transcription factors and altering nucleosome positioning. Here, we describe open chromatin mapping using Nicking Enzyme assisted sequencing (NicE-seq) for integrative epigenomic analysis. NicE-seq captures open chromatin sites in both fixed and native cells and reveals the genomic location of open chromatin sites (OCS) and transcription factor occupancy at single nucleotide resolution, with as few as 250 HCT116 cells. In HCT116 cells a large percentage of the OCS were coincident with DHS (DNaseI hypersensitive site) and ATAC-seq sites. OCSs correlated well with RNA pol II occupancy and transcriptionally active chromatin marks, while displaying a pattern contrasting to CpG methylation. ChIP CTCF peaks common to OCS and DHS displayed a strong correlation with H3K4me3 and H3K27ac marks. Further peaks unique to OCS and ChIP CTCF peaks also correlated strongly with H3K4me3, H3K27ac and higher transcription. Similar results were also obtained for Max and Sp1 transcription factors. Using NicE-seq we have demonstrated that HCT116 cells, treated with anti cancer drug decitabine, displayed time dependent accumulation of OCS coinciding with hypomethylation of the genome, particularly in SINE and satellite repetitive DNA. Differentially methylated regions (DMRs) were more pronounced in promoters, 5’UTR, CpG islands and exons. In summary, sequence specificity offered by a nicking enzyme allows a means to study open chromatin structure and hypomethylation of genomes, revealing the open chromatin landscape in cellular context.
2017-05-24 | GSE97889 | GEO
Project description:We develop a technique, named MNase hypersensitivity sequencing (MH-seq), to identify genomic regions associated with open chromatin in Arabidopsis thaliana. Genomic regions enriched with MH-seq reads are referred as MNase hypersensitive sites (MHSs). MHSs overlap with the majority (~90%) of the open chromatin identified previously by DNase-seq and ATAC-seq. Surprisingly, 22% MHSs are not covered by DNase-seq or ATAC-seq reads, which are referred to “specific MHSs” (sMHSs). sMHSs tend to be located away from promoters and a substantial portion of sMHSs are derived from transposable elements. Most interestingly, genomic regions containing sMHSs are enriched with epigenetic marks, including H3K27me3 and DNA methylation. In addition, sMHSs show a number of distinct characteristics including association with transcriptional repressors. Thus, sMHSs span distinct classes of open chromatin that may not be accessible to DNase I or Tn5. We hypothesize that the small size of the MNase enzyme relative to DNase I or Tn5 allows its access to relatively more condensed chromatin domains.
2019-12-22 | GSE142495 | GEO
Project description:Dense mapping of individual DNase I cleavages from intact nuclei isolated from wild type, sba1M-NM-^T and gcn5M-NM-^T yeast using high-throughput sequencing. Open chromatin status of wild type, sba1-/- and gcn5-/- yeast strains were generated by Dnase-seq.
2012-08-23 | E-GEOD-40255 | biostudies-arrayexpress
Project description:We develop a method called open chromatin enrichment and network Hi-C (OCEAN-C) for antibody-independent mapping of global open chromatin interactions. By integrating FAIRE-seq and Hi-C, OCEAN-C detects open chromatin interactions enriched by active cis-regulatory elements. We identify more than 10,000 hubs of open chromatin interactions (HOCIs) in human cells, which are mainly active promoters and enhancers bound by many DNA-binding proteins and form interaction networks crucial for gene transcription. In addition to identifying large-scale topological structures including topologically associated domains and A/B compartments, OCEAN-C can detect HOCI-mediated chromatin interactions that are strongly associated with gene expression, super-enhancers and broad H3K4me3 domains.
2018-03-25 | GSE100832 | GEO
Project description:ISDH-seq: a robust methodology for profiling and characterization of open chromatin
| PRJNA988012 | ENA
Project description:Distal cell-type-specific regulatory elements may be located at very large distances from the genes that they control and are often hidden within intergenic regions or in introns of other genes. The development of methods that enable mapping of regions of open chromatin genome wide has greatly advanced the identification and characterisation of these elements. Here we use DNase I hypersensitivity mapping followed by deep sequencing (DNase-seq) to generate a map of open chromatin in primary human tracheal epithelial (HTE) cells and use bioinformatic approaches to characterise the distribution of these sites within the genome and with respect to gene promoters, intronic and intergenic regions. Genes with THE-selective open chromatin at their promoters were associated with multiple pathways of epithelial function and differentiation. The data predict novel cell-type-specific regulatory elements for genes involved in HTE cell function, such as structural proteins and ion channels, and the transcription factors that may interact with them to control gene expression. Moreover, the map of open chromatin can identify the location of potentially critical regulatory elements in genome-wide association studies (GWAS) in which the strongest association is with single nucleotide polymorphisms in non-coding regions of the genome. We demonstrate its relevance to a recent GWAS that identifies modifiers of cystic fibrosis lung disease severity. Since HTE cells have many functional similarities with bronchial epithelial cells and other differentiated cells in the respiratory epithelium, these data are of direct relevance to elucidating the molecular basis of normal lung function and lung disease. To identify cis-regulatory elements for genes expressed in human tracheal epithelial cells we generated genome-wide maps of open chromatin by DNase-seq. HTE cells were isolated from these trachea and grown as described previously (Davis P.B. et al.1990).
2013-11-08 | E-GEOD-52179 | biostudies-arrayexpress
Project description:This data was generated by ENCODE. If you have questions about the data, contact the submitting laboratory directly (Terry Furey mailto:tsfurey@duke.edu). If you have questions about the Genome Browser track associated with this data, contact ENCODE (mailto:genome@soe.ucsc.edu). These tracks display DNaseI hypersensitivity (HS) evidence as part of the four Open Chromatin track sets. DNaseI is an enzyme that has long been used to map general chromatin accessibility, and DNaseI "hypersensitivity" is a feature of active cis-regulatory sequences. The use of this method has led to the discovery of functional regulatory elements that include promoters, enhancers, silencers, insulators, locus control regions, and novel elements. DNaseI hypersensitivity signifies chromatin accessibility following binding of trans-acting factors in place of a canonical nucleosome. Together with FAIRE and ChIP-seq experiments, these tracks display the locations of active regulatory elements identified as open chromatin in multiple cell types (http://hgwdev.cse.ucsc.edu/cgi-bin/hgEncodeVocab?type=cellType) from the Duke, UNC-Chapel Hill, UT-Austin, and EBI ENCODE group. Within this project, open chromatin was identified using two independent and complementary methods: these DNaseI HS assays and Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE), combined with chromatin immunoprecipitation (ChIP) for select regulatory factors. DNaseI HS and FAIRE provide assay cross-validation with commonly identified regions delineating the highest confidence areas of open chromatin. ChIP assays provide functional validation and preliminary annotation of a subset of open chromatin sites. Each method employed Illumina (formerly Solexa) sequencing by synthesis as the detection platform. The Tier 1 and Tier 2 cell types were additional verified by a second platform, high-resolution 1% ENCODE tiled microarrays supplied by NimbleGen. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf Cells were grown according to the approved ENCODE cell culture protocols (http://hgwdev.cse.ucsc.edu/ENCODE/protocols/cell). DNaseI hypersensitive sites were isolated using methods called DNase-seq or DNase-chip (Song and Crawford, 2010; Boyle et al., 2008a; Crawford et al., 2006). Briefly, cells were lysed with NP40, and intact nuclei were digested with optimal levels of DNaseI enzyme. DNaseI digested ends were captured from three different DNase concentrations, and material was sequenced using Illumina (Solexa) sequencing. DNase-seq data for Tier 1 and Tier 2 cell lines were verified by comparing multiple independent growths (replicates) and determining the reproducibility of the data. In general, cell lines were verified if 80% of the top 50,000 peaks in one replicate are detected in the top 100,000 peaks of a second replicate. For some cell types, additional verification was performed using similar material hybridized to NimbleGen Human ENCODE tiling arrays (1% of the genome) along with the input DNA as reference (DNase-chip). A more detailed protocol is available at http://hgwdev.cse.ucsc.edu/ENCODE/protocols/general/Duke_DNase_protocol.pdf. The read length for sequences from DNase-seq are 20 bases long due to a MmeI cutting step of the approximately >50kb DNA fragments extracted after DNaseI digestion. Sequences from each experiment were aligned to the genome using BWA (Li et al., 2010) for the NCBI 36 (hg19) assembly. The command used for these alignments was > bwa aln -t 8 genome.fa s_1.sequence.txt.bfq > s_1.sequence.txt.sai Where genome.fa is the whole genome sequence and s_1.sequence.txt.bfq is one lane of sequences convert into the required bfq format. Sequences from multiple lanes are combined for a single replicate using the bwa samse command, and converted in the sam/bam format using samtools. Only those that aligned to 4 or fewer locations were retained. Other sequences were also filtered based on their alignment to problematic regions (such as satellites and rRNA genes - see supplemental materials at http://hgdownload.cse.ucsc.edu/goldenPath/hg19/encodeDCC/wgEncodeOpenChromDnase/supplemental/). The mappings of these short reads to the genome are available for download at http://hgwdev.cse.ucsc.edu/cgi-bin/hgFileUi?g=wgEncodeOpenChromDnase. The resulting digital signal was converted to a continuous wiggle track using F-Seq that employs Parzen kernel density estimation to create base pair scores (Boyle et al., 2008b). Input data has been generated for several cell lines. These are used directly to create a control/background model used for F-Seq when generating signal annotations for these cell lines. These models are meant to correct for sequencing biases, alignment artifacts, and copy number changes in these cell lines. Input data is not being generated directly for other cell lines. Instead, a general background model was derived from the available Input data sets. This should provide corrections for sequencing biases and alignment artifacts, but will not correct for cell type specific copy number changes. The exact command used for this step is > fseq -l 600 -v -f 0 -b <bff files> -p <iff files> aligments.bed where the (bff files) are the background files based on alignability, the (iff files) are the background files based on the Input experiments, and alignments.bed are a bed file of filtered sequence alignments. Discrete DNaseI HS sites (peaks) were identified from DNase-seq F-seq density signal. Significant regions were determined by fitting the data to a gamma distribution to calculate p-values. Contiguous regions where p-values were below a 0.05/0.01 threshold were considered significant. Data from the high-resolution 1% ENCODE tiled microarrays supplied by NimbleGen were normalized using the Tukey biweight normalization, and peaks were called using ChIPOTle (Buck, et al., 2005) at multiple levels of significance. Regions matched on size to these peaks that were devoid of any significant signal were also created as a null model. These data were used for additional verification of Tier 1 and Tier 2 cell lines by ROC analysis. Files containing this data can be found in the Downloads directory (http://hgwdev.cse.ucsc.edu/cgi-bin/hgFileUi?db=hg19&g=wgEncodeOpenChromDnase) labeled Validation view. Release 1 (April 2011) of this track consists of a remapping of all previously released experiments to the human reference genome GRCh37/hg19 (these data were previously mapped to NCBI36/hg18; please see the Release Notes section of the hg18 Open Chromatin track (http://hgwdev.cse.ucsc.edu/cgi-bin/hgTrackUi?db=hg18&g=wgEncodeChromatinMap) for information on the NCBI36/hg18 releases of the data). There are 21 new DNaseI experiments in this release, on 19 new cell lines. New to this release is a reconfiguration of how this track is displayed in relation to other tracks from the Duke/UNC/UT-Austin/EBI group. A synthesis of open chromatin evidence from the three assay types was compiled for Tier 1 and 2 cell lines plus NHEK will also be added in this release and can be previewed in: Open Chromatin Synthesis (http://genome-preview.cse.ucsc.edu/cgi-bin/hgTrackUi?db=hg19&g=wgEncodeOpenChromSynth). Enhancer and Insulator Functional assays: A subset of DNase and FAIRE regions were cloned into functional tissue culture reporter assays to test for enhancer and insulator activity. Coordinates and results from these experiments can be found at http://hgdownload.cse.ucsc.edu/goldenPath/hg19/encodeDCC/wgEncodeOpenChromDnase/supplemental/.
2011-10-14 | E-GEOD-32970 | biostudies-arrayexpress
Project description:The epithelium lining the epididymis in the male reproductive tract maintains a luminal environment that promotes sperm cell maturation. This process is dependent on the coordinated expression of many genes that encode proteins with a role in epithelial transport. We previously generated genome-wide maps of open chromatin in primary human fetal epididymis epithelial cells to identify potential regulatory elements controlling coordinated gene expression in the epididymis epithelium. Subsequent in silico analysis identified transcription factor binding sites (TFBS) that were over-represented in the HEE open chromatin, include the motif for paired box 2 (PAX2). PAX2 is a critical transcriptional regulator of urogenital tract development, which is well studied in the kidney but is unexplored in the epididymis. Due to the limited lifespan of primary HEE cells in culture we investigated the role of PAX2 in an immortalized HEE cell line (REP). First, REP cells were evaluated by DNase-seq and their open chromatin map overlapped that of primary HEE cells at ~ 65% of sites. Moreover, the PAX2-binding motif was again identified as an overrepresented TFBS within intergenic open chromatin, though on fewer chromosomes than in the primary HEE cells. To identify PAX2-target genes in REP cells, RNA-seq analysis was performed after siRNA-mediated depletion of PAX2 in comparison to a non-targeting siRNA. In response to PAX2-represssion, 3142 transcripts were differentially expressed (1334 up-regulated and 1808 down-regulated). Novel PAX2 targets included multiple genes encoding proteins with a predicted function in the epididymis epithelium. examination of open chromatin region in REP cells with 2 replicates
2015-01-07 | E-GEOD-59782 | biostudies-arrayexpress
Project description:The epithelium lining the epididymis in the male reproductive tract maintains a luminal environment that promotes sperm cell maturation. This process is dependent on the coordinated expression of many genes that encode proteins with a role in epithelial transport. We previously generated genome-wide maps of open chromatin in primary human fetal epididymis epithelial cells to identify potential regulatory elements controlling coordinated gene expression in the epididymis epithelium. Subsequent in silico analysis identified transcription factor binding sites (TFBS) that were over-represented in the HEE open chromatin, include the motif for paired box 2 (PAX2). PAX2 is a critical transcriptional regulator of urogenital tract development, which is well studied in the kidney but is unexplored in the epididymis. Due to the limited lifespan of primary HEE cells in culture we investigated the role of PAX2 in an immortalized HEE cell line (REP). First, REP cells were evaluated by DNase-seq and their open chromatin map overlapped that of primary HEE cells at ~ 65% of sites. Moreover, the PAX2-binding motif was again identified as an overrepresented TFBS within intergenic open chromatin, though on fewer chromosomes than in the primary HEE cells. To identify PAX2-target genes in REP cells, RNA-seq analysis was performed after siRNA-mediated depletion of PAX2 in comparison to a non-targeting siRNA. In response to PAX2-represssion, 3142 transcripts were differentially expressed (1334 up-regulated and 1808 down-regulated). Novel PAX2 targets included multiple genes encoding proteins with a predicted function in the epididymis epithelium. mRNA profile of control and PAX2 knockdown REP cells
2015-01-07 | E-GEOD-59781 | biostudies-arrayexpress
Project description:Open chromatin provides access to a wide spectrum of DNA binding proteins for DNA metabolism processes such as transcription, repair, recombination, and replication. In this regard, open chromatin profiling has been widely used to identify the location of regulatory regions, including promoters, enhancers, insulators, silencers, replication origins, and recombination hotspots. For a quantitative getic analysis of chromatin regulation, we generated open chromatin maps of 100 yeast samples including the parental strains (BY and RM, and two replicates for each) and their descendants by using the FAIRE-seq technique Open chromatin in two parental strains and 94 segregants of their crossing
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