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Series GSE31755 Query DataSets for GSE31755
Status Public on Aug 31, 2011
Title Histone Modifications by ChIP-seq from ENCODE/Stanford/Yale/Davis/Harvard
Project ENCODE
Organism Homo sapiens
Experiment type Genome binding/occupancy profiling by high throughput sequencing
Summary This data was generated by ENCODE. If you have questions about the data, contact the submitting laboratory directly (Peggy Farnham mailto:pfarnham@usc.edu for questions concerning data collection and usage and Philip Cayting mailto:pcayting@stanford.edu for data scoring and submission inquiries). If you have questions about the Genome Browser track associated with this data, contact ENCODE (mailto:genome@soe.ucsc.edu).

This track, produced as part of the ENCODE Project, displays maps of histone modifications genome-wide using ChIP-seq in different cell lines. The ChIP-seq method involves first using formaldehyde to cross-link histones and other DNA-associated proteins to genomic DNA within cells. The cross-linked chromatin is subsequently extracted, sheared, and immunoprecipitated using specific antibodies. After reversal of cross-links, the immunoprecipitated DNA is sequenced and mapped to the human reference genome. The relative enrichment of each antibody-target (epitope) across the genome is inferred from the density of mapped fragments.
Chemical modifications (e.g. methylation or acetylation) of the histone proteins present in chromatin influence gene expression by changing how accessible the chromatin is to transcription factors. Shown for each experiment (defined as a particular antibody and a particular cell type) is a track of enrichment for the specifically modified histone (Signal), along with sites that have the greatest enrichment (Peaks). Also included for each cell type is the input signal, which represents the control condition where no antibody targeting was performed. In general the following chemical modifications have associated genetic phenotypes:
H3K4me3 and H3K9Ac are considered to be marks of active or potentially active promoter regions. H3K4me1 and H3K27Ac are considered to be marks of active or potentially active enhancer regions. H3K36me3 and H3K79me2 are considered to be marks of transcriptional elongation. H3K27me3 and H3K9me3 are considered to be marks of inactive regions.

For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf
 
Overall design Cells were grown according to the approved ENCODE cell culture protocols. Briefly, cells were crosslinked, chromatin was extracted and sonicated using a Bioruptor sonicator (Diagenode) to an average size of 300-500bp, and individual ChIP assays were performed using antibodies to modified histones. For the K562 and Ntera2 histone ChIP-seq samples, immunoprecipitates were collected using protein G-coupled magnetic beads; a detailed ChIP and library protocol can be found at http://www.roadmapepigenomics.org/protocols. For the U2OS histone ChIP-seq samples, immunoprecipitates were collected using StaphA cells; a detailed protocol can be found at http://expression.genomecenter.ucdavis.edu/chip.html. Library DNA was quantitated using either a Nanodrop or a BioAnalyzer and sequenced on an Illumina GA2.
The sequencing reads were mapped to the genome using the Eland alignment program. ChIP-seq data was scored based on sequence reads (length ~30 bps) that align uniquely to the human genome. From the mapped tags, a signal map of ChIP DNA fragments (average fragment length ~ 200 bp) was constructed where the signal height is the number of overlapping fragments at each nucleotide position in the genome.
For each 1 Mb segment of each chromosome, a peak height threshold was determined by requiring a false discovery rate <= 0.05 when comparing the number of peaks above threshold as compared to the number obtained from multiple simulations of a random null background with the same number of mapped reads (also accounting for the fraction of mapable bases for sequence tags in that 1 Mb segment). The number of mapped tags in a putative binding region is compared to the normalized (normalized by correlating tag counts in genomic 10 kb windows) number of mapped tags in the same region from an input DNA control. Using a binomial test, only regions that have a p-value <= 0.05 are considered to be significantly enriched compared to the input DNA control.
Web link http://genome.ucsc.edu/cgi-bin/hgTrackUi?db=hg19&g=wgEncodeSydhHistone
 
Contributor(s) Farnham P, Snyder M, Cayting P
Citation missing Has this study been published? Please login to update or notify GEO.
BioProject PRJNA63443
Submission date Aug 30, 2011
Last update date May 15, 2019
Contact name ENCODE DCC
E-mail(s) encode-help@lists.stanford.edu
Organization name ENCODE DCC
Street address 300 Pasteur Dr
City Stanford
State/province CA
ZIP/Postal code 94305-5120
Country USA
 
Platforms (1)
GPL9052 Illumina Genome Analyzer (Homo sapiens)
Samples (32)
GSM788069 USC_ChipSeq_U2OS_Input_UCDavis
GSM788070 USC_ChipSeq_PBMC_Input_UCDavis
GSM788071 USC_ChipSeq_NT2-D1_H3K27me3B_UCDavis
Relations
SRA SRP008013

Download family Format
SOFT formatted family file(s) SOFTHelp
MINiML formatted family file(s) MINiMLHelp
Series Matrix File(s) TXTHelp

Supplementary file Size Download File type/resource
GSE31755_RAW.tar 9.7 Gb (http)(custom) TAR (of BIGWIG, NARROWPEAK)
GSE31755_run_info_with_UCSC_objects.txt.gz 1.5 Kb (ftp)(http) TXT
SRA Run SelectorHelp
Raw data are available in SRA
Processed data provided as supplementary file
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