Site-specific silencing of regulatory elements as a mechanism of X-inactivation
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE39406 | GEO | 2012/11/21
SECONDARY ACCESSION(S): PRJNA170844
REPOSITORIES: GEO
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Project description:The inactive X chromosome’s (Xi) physical territory is microscopically devoid of transcriptional hallmarks and enriched in silencing-associated modifications. How these microscopic signatures relate to specific Xi sequence is unknown. This study reports the profiling of Xi gene expression and chromatin states at high-resolution via allele-specific sequencing in F1 hybrid mouse trophoblast stem cells (TSCs). Datasets provided include those generated from strand-specific RNA-Seq, ChIP-Seq, FAIRE-Seq, and DNase-Seq protocols. Included for each dataset are FASTQ files, BED alignments and WIG files with coordinates relative to UCSC genome build mm9, and _snp files that report the location of all SNP-overlapping reads. The F1 TSC lines profiled were generated from crosses between CAST/EiJ (Cast) and C57BL/6J (B6) mice. C/B denotes a Cast mother and B6 father, and B/C denotes a B6 mother and Cast father.
2012-11-21 | E-GEOD-39406 | biostudies-arrayexpress
Project description:This Series reports data from a CTCF ChIP-Seq experiment performed in F1-hybrid mouse trophoblast stem cells (TSCs). The data are part of a larger study examining inactive X gene expression and chromatin states, reported as GEO Series GSE39406. Included for this dataset are FASTQ files, BED alignments and WIG files with coordinates relative to UCSC genome build mm9, and _snp files that report the location of all SNP-overlapping reads
2012-09-08 | GSE40667 | GEO
Project description:This Series reports data from a CTCF ChIP-Seq experiment performed in F1-hybrid mouse trophoblast stem cells (TSCs). The data are part of a larger study examining inactive X gene expression and chromatin states, reported as GEO Series GSE39406. Included for this dataset are FASTQ files, BED alignments and WIG files with coordinates relative to UCSC genome build mm9, and _snp files that report the location of all SNP-overlapping reads Single CTCF ChIP-Seq experiment
2012-09-08 | E-GEOD-40667 | biostudies-arrayexpress
Project description:The product of dosage compensation in human females is the compacted inactive X chromosome (Xi). Here we show that loss of SET domain bifurcated 1 (SETDB1) results in decompaction of the Xi territory coupled with reactivation on the Xi of a powerful enhancer within the 1.4 Mb interleukin-1 receptor accessory protein like 1 (IL1RAPL1) gene at Xp21.2. The enhancer is centrally located in a 0.5 Mb region corresponding to the 3’ third of the IL1RAPL1 locus that transitions from a heterochromatic territory to a euchromatic configuration on the Xi in the absence of SETDB1. This same region showing chromatin instability is part of a common chromosome fragile site that is frequently deleted or rearranged in patients afflicted with intellectual disability and other neurological ailments. Immediately adjacent to the enhancer is an ERVL-MaLR element that drives bi-directional transcription of novel long sense and antisense transcripts. Deletion of the enhancer from the Xa (but not Xi), resulted in detection of bi-directional expression from the Xi coupled with decompaction of the chromosome territory, supporting a critical role for SETDB1 in maintaining this interval in a silent state to facilitate Xi compaction.
2018-11-14 | GSE113399 | GEO
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 Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE) evidence as part of the four Open Chromatin track sets. FAIRE is a method to isolate and identify nucleosome-depleted regions of the genome. FAIRE was initially discovered in yeast and subsequently shown to identify active regulatory elements in human cells (Giresi et al., 2007). Similar to DNaseI HS, FAIRE appears to identify functional regulatory elements that include promoters, enhancers, silencers, insulators, locus control regions and novel elements. Together with DNaseI HS 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: DNaseI hypersensitivity (HS) and these FAIRE assays, 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 additionally verified by a second platform, high-resolution 1% ENCODE tiled microarrays supplied by NimbleGen. Release 1 (March 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://genome.ucsc.edu/cgi-bin/hgTrackUi?db=hg18&g=wgEncodeChromatinMap) for information on the NCBI36/hg18 releases of the data). -There are 12 new FAIRE experiments in this release, on 10 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/wgEncodeOpenChromFaire/supplemental/. 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). FAIRE was performed (Giresi et al., 2007) by cross-linking proteins to DNA using 1% formaldehyde solution, and the complex was sheared using sonication. Phenol/chloroform extractions were performed to remove DNA fragments cross-linked to protein. The DNA recovered in the aqueous phase was sequenced using an Illumina (Solexa) sequencing system. FAIRE-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. For some cell types, additional verification was performed using the same material but hybridized to NimbleGen Human ENCODE tiling arrays (1% of the genome) along with the input DNA as reference (FAIRE-chip). A more detailed protocol is available at http://hgwdev.cse.ucsc.edu/ENCODE/protocols/general/FAIRE_UNC_procedure.pdf. Also see Giresi et al., 2009. DNA fragments isolated by FAIRE are 100-200 bp in length, with the average length being 134 bp. 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 converted 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 http://hgdownload.cse.ucsc.edu/goldenPath/hg19/encodeDCC/wgEncodeOpenChromFaire/supplemental/). The mappings of these short reads to the genome are available for download at http://hgwdev.cse.ucsc.edu/cgi-bin/hgFileUi?g=wgEncodeOpenChromFaire. 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 800 -v -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 FAIRE sites (peaks) were identified from FAIRE-seq F-seq density signal. Significant regions were determined by fitting the data to a gamma distribution to calculate p-values. Contiguous regions 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 labeled Validation view (http://hgwdev.cse.ucsc.edu/cgi-bin/hgFileUi?db=hg19&g=wgEncodeOpenChromFaire).
2012-01-24 | E-GEOD-35239 | biostudies-arrayexpress
Project description:This data was generated by ENCODE. If you have questions about the data, contact the submitting laboratory directly (Georgi K. Marinov mailto:georgi@caltech.edu (data coordination/informatics/experimental), Diane Trout mailto:diane@caltech.edu (informatics) Brian Williams mailto:bawilli_91125@yahoo.com (experimental)). If you have questions about the Genome Browser track associated with this data, contact ENCODE (mailto:genome@soe.ucsc.edu). RNA-seq is a method for mapping and quantifying the transcriptome of any organism that has a genomic DNA sequence assembly (Mortazavi et al., 2008). RNA-seq is performed by reverse-transcribing an RNA sample into cDNA, followed by high-throughput DNA sequencing, which was done here on the Illumina HiSeq sequencer. The transcriptome measurements shown on these tracks were performed on polyA selected RNA (http://hgwdev.cse.ucsc.edu/cgi-bin/hgEncodeVocab?term=longPolyA&type=rnaExtract) from total cellular RNA (http://hgwdev.cse.ucsc.edu/cgi-bin/hgEncodeVocab?term=cell&type=localization). PolyA-selected RNA was fragmented by magnesium-catalyzed hydrolysis and then converted into cDNA by random priming and amplified. Paired-end 2x100 bp reads were obtained from each end of a cDNA fragment. Reads were aligned to the mm9 human reference genome using TopHat (Trapnell et al., 2009), a program specifically designed to align RNA-seq reads and discover splice junctions de novo. All sequence and alignments files are available at http://hgwdev.cse.ucsc.edu/cgi-bin/hgFileUi?db=mm9&g=wgEncodeCaltechRnaSeq.
2012-05-10 | GSE37909 | GEO
Project description:The inactive X chromosome (Xi) serves as a model to understand gene silencing on a global scale. Here, we perform identification of direct RNA interacting proteins? (iDRiP) to isolate a comprehensive protein interactome for Xist, an RNA required for Xi silencing. We discover multiple classes of interactors, including cohesins, condensins, topoisomerases, RNA helicases, chromatin remodelers and modifiers, which synergistically repress Xi transcription. Inhibiting two or three interactors destabilizes silencing. While Xist attracts some interactors, it repels architectural factors. Xist evicts cohesins from the Xi and directs an Xi-specific chromosome conformation. Upon deleting Xist, the Xi acquires the cohesin-binding and chromosomal architecture of the active X. Our study unveils many layers of Xi repression and demonstrates a central role for RNA in the topological organization of mammalian chromosomes. The RNA-seq data sets generated in this study provide a resource for examining the effects of knockdowns of various Xist-interacting proteins on gene expression. The ChIP-seq data sets provide a comprehensive set of data examining CTCF and cohesion binding the X-chromosome, and the effects of deleting Xist on CTCF and cohesion binding. The Hi-C data is an allele-specific contact map of the X-chromosome higher-order chromatin structure in mouse. RNA-seq in 3 control and 10 knockdown cell lines. ChIP-seq for CTCF, Rad21 and Smc1a in wild-type fibroblasts and Xist-deletion fibroblasts. Hi-C in wild-type and Xist-deletion fibroblasts.
2015-06-19 | E-GEOD-67516 | biostudies-arrayexpress
Project description:We utilized FAIRE-seq to identify accesible chromatin in mouse embryonic-, epiblast-, and neural- stem cells in addition to mouse embryonic fibroblasts. Analysis of these data sets reveal cell type specific chromatin signatures that differentiate naïve and primed pluripotency. Functional analysis of type-specific peaks revealed cell-type specific enhancers. FAIRE-seq of mESC, EpiSC, NSC and MEF
2015-01-01 | E-GEOD-58520 | biostudies-arrayexpress
Project description:During interphase, the inactive X chromosome (Xi) adopts an unusual 3D configuration known as the Barr body and is largely transcriptionally silent. Despite the importance of X inactivation, little is known about the 3D configuration of Xi and its relationship to gene silencing. We recently showed that in humans, Xi exhibits two distinctive structural features. First, Xi is partitioned into two huge intervals, called superdomains, such that pairs of loci in each superdomain show an enhanced contact frequency with one another. The boundary between the two superdomains lies near DXZ4, a macrosatellite repeat spanning ~300kb, whose Xi allele extensively binds the protein CTCF. Second, Xi exhibits extremely large loops, up to 77Mb long, called superloops. DXZ4 lies at the anchor of several superloops. Here, we use 3D mapping to study the structure of Xi, focusing on the role of DXZ4. We show that superloops and superdomains are conserved across mammals. We develop a novel variant of our in situ Hi-C protocol, dubbed COLA (COncatemer Ligation Assay) to probe the higher order structures formed by the superloops. In COLA, in situ proximity ligation of multiple extremely short fragments produced by the enzyme CviJI is used to efficiently map simultaneous proximity among three or more loci. Using data from Hi-C and COLA, we demonstrate that DXZ4 and other superloop anchors tend to co-locate simultaneously within the same cells, a result that is confirmed by 3D-FISH. Finally, we examine the effects of deleting DXZ4 from Xi in human cells. Using in situ Hi-C, microscopy, and RNA-FISH, we show that superdomains and superloops disappear; that Xi frequently dissociates into multiple separate structures; and that transcriptional silencing on Xi is compromised. Deletion of DXZ4 from the active X chromosome (Xa) has no such effect. Thus, DXZ4 is essential for proper folding and silencing of Xi. Hi-C protocol was used on wildtype and DXZ4-deleted cells to examine the structure of Xi. A novel variant of our in situ Hi-C protocol, dubbed COLA (COncatemer Ligation Assay), was developed to probe the higher order structures formed by the superloops. This series also includes RNA-seq data on Retinal Pigmented Epithelial Cells (hTERT-RPE1). At the time of submission, processed data were available only for the RNA-seq samples. Submitter states that processed data files for HiC samples will be added to this series in the future.
2016-07-19 | E-GEOD-71831 | biostudies-arrayexpress
Project description:The spatial proximity between regulatory elements and their target genes has a profound affect on gene expression. X Chromosome Inactivation (XCI) is an epigenetic process by which an entire chromosome is rendered, for the most part, transcriptionally silent. A few genes are known to escape XCI and the mechanism for this escape remains unclear. Here, using mouse trophectodermal stem cells, we address whether specific chromosomal interactions facilitate escape from XCI by bringing escape-specific regulatory elements in close proximity to gene promoters. Our results suggest a model where escape from XCI occurs within topologically associated domains. As such, escaping genes and the regulatory sequences required for their escape are likely located within close linear proximity to each other. The datasets provided include those generated from allele-specific 4C-Seq of genes escaping XCI, genes subject to XCI, and non-genic regions of the X chromosome. FASTQ files, text files containing genomic coordiantes, and BED aligmnets are provided. All sequences were mapped relative to mouse genome build mm9.
2014-03-26 | GSE49111 | GEO