The Open Chromatin Landscape of Kaposi's Sarcoma-Associated Herpesvirus
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ABSTRACT:
ORGANISM(S): Human gammaherpesvirus 8
PROVIDER: GSE50581 | GEO | 2013/09/05
SECONDARY ACCESSION(S): PRJNA217979
REPOSITORIES: GEO
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Project description:KaposiM-bM-^@M-^Ys sarcoma-associated herpesvirus (KSHV) is an oncogenic gammaherpesvirus which establishes latent infection in endothelial and B cells, as well as in primary effusion lymphoma (PEL). During latency, the viral genome exists as a circular DNA minichromosome (episome) and is packaged into chromatin analogous to human chromosomes. Only a small subset of promoters, those which drive latent RNAs, are active in latent episomes. In general, nucleosome depletion (M-bM-^@M-^\open chromatinM-bM-^@M-^]) is a hallmark of eukaryotic regulatory elements such as promoters and transcriptional enhancers or insulators. We applied formaldehyde-assisted isolation of regulatory elements (FAIRE) followed by next-generation sequencing to identify regulatory elements in the KSHV genome and integrated these data with previously identified locations of histone modifications, RNA polymerase II occupancy, and CTCF binding sites. We found that (i) regions of open chromatin were not restricted to the transcriptionally defined latent loci; (ii) open chromatin was adjacent to regions harboring activating histone modifications, even at transcriptionally inactive loci; and (iii) CTCF binding sites fell within regions of open chromatin with few exceptions, including the constitutive LANA promoter and the vIL6 promoter. FAIRE-identified nucleosome depletion was similar among B and endothelial cell lineages, suggesting a common viral genome architecture in all forms of latency. Ten total samples analyzed by FAIRE-seq from latent KSHV-infected cell lines. Two replicates were performed for BC1, KSHV-BJAB, KSHV-HUVEC, and L1-TIVE cells using the Illumina HiSeq 2000 platform. For BCBL1 cells, 1 FAIRE-seq sample and 1 non-cross-linked control BCBL1 sample was analyzed using the Illumina GAIIx
2013-09-05 | E-GEOD-50581 | biostudies-arrayexpress
Project description:Chromatin-organizing factors, like CTCF and cohesins, have been implicated in the control of complex viral regulatory programs. We investigated the role of CTCF and cohesin in the control of the latent to lytic switch for Kaposi's Sarcoma-Associated Herpesvirus (KSHV). We found that cohesin subunits, but not CTCF, were required for the repression of KSHV immediate early gene transcription. Depletion of cohesin subunits Rad21, SMC1, or SMC3 resulted in lytic cycle gene transcription and viral DNA replication. In contrast, depletion of CTCF failed to induce lytic transcription or DNA replication. ChiP-Seq analysis revealed that cohesins and CTCF bound to several sites within the immediate early control regions for ORF50 and more distal 5' sites that also regulate the divergently transcribed ORF45-46-47 gene cluster. Rad21 depletion led to a robust increase in ORF45 and ORF47 transcripts, with similar kinetics to that observed with chemical induction by sodium butyrate. During latency, the chromatin between the ORF45 and ORF50 transcription start sites was enriched in histone H3K4me3 with elevated H3K9ac at the ORF45 promoter and elevated H3K27me3 at the ORF50 promoter. A paused form of RNA pol II was loosely associated with the ORF45 promoter region during latency, but was converted to an active elongating form upon reactivation induced by Rad21 depletion. Butyrate-induced transcription of ORF45 and ORF47 was resistant to cyclohexamide, suggesting that these genes have immediate early features similar to ORF50. Butyrate-treatment caused the rapid dissociation of cohesins and loss of CTCF binding at the immediate early gene locus, suggesting that cohesins may be a direct target of butyrate-mediated lytic induction. Our findings implicate cohesins as a major repressor of KSHV lytic gene activation, and function coordinately with CTCF to regulate the switch between latent and lytic gene activity. Study of chromatin-organizing factors, like CTCF and cohesins.
2012-06-02 | E-GEOD-38411 | biostudies-arrayexpress
Project description:The compaction degree of chromatin is intimately related to its functionality and active cis-regulatory elements typically exist within open chromatin regions depleted in nucleosomes (Heintzman et al. 2007; Boyle et al. 2008). These domains can be identified using Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE) that allows for enrichment of nucleosome-depleted genomic regions when cross-linked chromatin is subjected to phenol-chloroform extraction (Nagy et al. 2003; Hogan et al. 2006) Here, chromatin structure was analyzed in MCF7 and LNCaP cells using Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE) (Nagy et al. 2003; Hogan et al. 2006) Keywords: FAIRE-chip
2009-01-07 | GSE11579 | GEO
Project description:Kaposi’s sarcoma-associated herpesvirus (KSHV) is a g-herpesvirus which persists as circular extrachromasomal DNA in the nucleus during latent infection. During latency a limited number of viral proteins are expressed, including LANA (latency-associated nuclear antigen). LANA is a multi-functional protein known to interact with transcriptional regulators and chromatin remodelers, and to regulate the LANA and RTA promoters. We hypothesized that LANA may contribute to the establishment of latency through controlling chromatinization and histone modification of KSHV episomes. We performed ChIP-seq analysis and correlated H3K4me3, H3K27me3, polII, and LANA occupancy of the KSHV genome at nucleotide resolution. Epigenetic marks were analyzed in BCBL-1 lymphoid cells and in telomerase-immortalized vein endothelial TIVE-LTC cells. We found that the transcription active mark H3K4me3, but not silencing mark H3K27me3, was enriched at KSHV regions where LANA is bound. Co-occupancy of LANA and H3K4 was also detected on 167 host genes, of which 89 are actively transcribed. By comparing LANA occupancy with the profiling of 43 transcription factors from ENCODE, a subset of transcription factors was enriched at regions where LANA is bound, including znf143, CTCF, and Stat1. These results indicate that LANA also plays a role in modulating expression of host genes. Co-immunoprecipitation of LANA with the H3K4 methyltransferase hSET1 suggests that LANA recruits hSET1 to specific loci on the viral genome, leading to H3K4 methylation and ensuring transcription of latency-associated genes. Host gene expression may be regulated by the same mechanism. LANA binding was correlated with the distribution in the latent KSHV genome of the transcription active histone modification H3K4me3, the silencing mark H3K27me3, and RNA polymerase II, using cells of lymphoid and endothelial origin. A similar analysis was done for the human genome. Biological replicates (BR) and technical replicates (TR) were included.
2014-10-27 | E-GEOD-52421 | biostudies-arrayexpress
Project description:The compaction degree of chromatin is intimately related to its functionality and active cis-regulatory elements typically exist within open chromatin regions depleted in nucleosomes (Heintzman et al. 2007; Boyle et al. 2008). These domains can be identified using Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE) that allows for enrichment of nucleosome-depleted genomic regions when cross-linked chromatin is subjected to phenol-chloroform extraction (Nagy et al. 2003; Hogan et al. 2006) Here, chromatin structure was analyzed in MCF7 and LNCaP cells using Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE) (Nagy et al. 2003; Hogan et al. 2006) Keywords: FAIRE-chip MCF7 and LNCaP cells were grown in full media, cross-linked and processed as in (Nagy et al. 2003; Hogan et al. 2006). DNA obtained by FAIRE was hybridized to Human Affymetrix tiled array F. Triplicates of FAIRE and input DNA are provided (4 inputs for MCF7 cells).
2010-05-14 | E-GEOD-11579 | biostudies-arrayexpress
Project description:The human body contains thousands of unique cell types, each with specialized functions. Cell identity is governed in large part by gene transcription programs, which are determined by regulatory elements encoded in DNA. To identify regulatory elements active in seven cell lines representative of diverse human cell types, we used DNase-seq and FAIRE-seq to map M-CM-"M-BM-^@M-BM-^\open chromatinM-CM-"M-BM-^@M-BM-^]. Over 870,000 DNaseI or FAIRE sites, which correspond largely to nucleosome depleted regions (NDRs), were identified across the seven cell lines, covering nearly 9% of the genome. The combination of DNaseI and FAIRE is more effective than either assay alone in identifying likely regulatory elements, as judged by coincidence with transcription factor binding locations determined in the same cells. Open chromatin common to all seven cell types tended to be at or near transcription start sites and encompassed more CTCF binding sites, while open chromatin sites found in only one cell type were typically located away from transcription start sites, and contained DNA motifs recognized by regulators of cell-type identity. As one example of its ability to identify functional DNA, we show that open chromatin regions bound by CTCF are potent insulators. We identified clusters of open regulatory elements (COREs) that were physically near each other and whose appearance was coordinated among one or more cell types. Gene expression and RNA Pol II binding data support the hypothesis that COREs control gene activity required for the maintenance of cell-type identity. This publicly available atlas of regulatory elements may prove valuable in identifying non-coding DNA sequence variants that are causally linked to human disease. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf DNase-seq, FAIRE-seq, and ChIP-seq were performed on seven human cell lines: GM12878 (lymphoblastoid), K562 (leukemia), HepG2 (hepatocellular carcinoma), HelaS3 (cervical carcinoma), HUVEC (human umbilical vein endothelial cells), NHEK (keratinocytes), and H1-ES (embryonic stem cells). For each cell line, two or three replicates were independently grown and split into three, one for each of the three experimental methods. Control ChIP experiments were performed on five of the cell lines with NHEK and H1-ES being excluded due to lack of material.
2011-06-29 | E-GEOD-30224 | biostudies-arrayexpress
Project description:The human body contains thousands of unique cell types, each with specialized functions. Cell identity is governed in large part by gene transcription programs, which are determined by regulatory elements encoded in DNA. To identify regulatory elements active in seven cell lines representative of diverse human cell types, we used DNase-seq and FAIRE-seq to map M-CM-"M-BM-^@M-BM-^\open chromatinM-CM-"M-BM-^@M-BM-^]. Over 870,000 DNaseI or FAIRE sites, which correspond largely to nucleosome depleted regions (NDRs), were identified across the seven cell lines, covering nearly 9% of the genome. The combination of DNaseI and FAIRE is more effective than either assay alone in identifying likely regulatory elements, as judged by coincidence with transcription factor binding locations determined in the same cells. Open chromatin common to all seven cell types tended to be at or near transcription start sites and encompassed more CTCF binding sites, while open chromatin sites found in only one cell type were typically located away from transcription start sites, and contained DNA motifs recognized by regulators of cell-type identity. As one example of its ability to identify functional DNA, we show that open chromatin regions bound by CTCF are potent insulators. We identified clusters of open regulatory elements (COREs) that were physically near each other and whose appearance was coordinated among one or more cell types. Gene expression and RNA Pol II binding data support the hypothesis that COREs control gene activity required for the maintenance of cell-type identity. This publicly available atlas of regulatory elements may prove valuable in identifying non-coding DNA sequence variants that are causally linked to human disease. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf DNase-seq, FAIRE-seq, and ChIP-seq were performed on seven human cell lines: GM12878 (lymphoblastoid), K562 (leukemia), HepG2 (hepatocellular carcinoma), HelaS3 (cervical carcinoma), HUVEC (human umbilical vein endothelial cells), NHEK (keratinocytes), and H1-ES (embryonic stem cells). For each cell line, two or three replicates were independently grown and split into three, one for each of the three experimental methods. Control ChIP experiments were performed on five of the cell lines with NHEK and H1-ES being excluded due to lack of material.
2011-06-29 | E-GEOD-30226 | biostudies-arrayexpress
Project description:The human body contains thousands of unique cell types, each with specialized functions. Cell identity is governed in large part by gene transcription programs, which are determined by regulatory elements encoded in DNA. To identify regulatory elements active in seven cell lines representative of diverse human cell types, we used DNase-seq and FAIRE-seq to map M-CM-"M-BM-^@M-BM-^\open chromatinM-CM-"M-BM-^@M-BM-^]. Over 870,000 DNaseI or FAIRE sites, which correspond largely to nucleosome depleted regions (NDRs), were identified across the seven cell lines, covering nearly 9% of the genome. The combination of DNaseI and FAIRE is more effective than either assay alone in identifying likely regulatory elements, as judged by coincidence with transcription factor binding locations determined in the same cells. Open chromatin common to all seven cell types tended to be at or near transcription start sites and encompassed more CTCF binding sites, while open chromatin sites found in only one cell type were typically located away from transcription start sites, and contained DNA motifs recognized by regulators of cell-type identity. As one example of its ability to identify functional DNA, we show that open chromatin regions bound by CTCF are potent insulators. We identified clusters of open regulatory elements (COREs) that were physically near each other and whose appearance was coordinated among one or more cell types. Gene expression and RNA Pol II binding data support the hypothesis that COREs control gene activity required for the maintenance of cell-type identity. This publicly available atlas of regulatory elements may prove valuable in identifying non-coding DNA sequence variants that are causally linked to human disease. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf DNase-seq, FAIRE-seq, and ChIP-seq were performed on seven human cell lines: GM12878 (lymphoblastoid), K562 (leukemia), HepG2 (hepatocellular carcinoma), HelaS3 (cervical carcinoma), HUVEC (human umbilical vein endothelial cells), NHEK (keratinocytes), and H1-ES (embryonic stem cells). For each cell line, two or three replicates were independently grown and split into three, one for each of the three experimental methods. Control ChIP experiments were performed on five of the cell lines with NHEK and H1-ES being excluded due to lack of material.
2011-06-29 | E-GEOD-30225 | biostudies-arrayexpress
Project description:These tracks display a synthesis of evidence from different assays as part of the four Open Chromatin track sets. This track displays open chromatin regions and/or transcription factor binding sites identified in multiple cell types by one or more complementary methodologies, DNaseI hypersensitivity (HS) (Duke DNaseI HS), Formaldehyde-Assisted Isolation of Regulatory Elements (FAIRE) (UNC FAIRE), and chromatin immunoprecipitation (ChIP) for select regulatory factors (UTA TFBS). Each methodology was performed on the same cell type using identical growth conditions. (Note: Data for some or all ChIP experiments may not be available for all cell types). Regions that overlap between methodologies identify regulatory elements that are cross-validated indicating high confidence regions. In addition, multiple lines of evidence suggest that regions detected by a single assay (e.g., DNase-only or FAIRE-only) are also biologically relevant (Song et al., submitted). DNaseI HS data: 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. FAIRE data: FAIRE (Formaldehyde Assisted Isolation of Regulatory Elements) 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. ChIP data: ChIP (Chromatin Immunoprecipitation) is a method to identify the specific location of proteins that are directly or indirectly bound to genomic DNA. By identifying the binding location of sequence-specific transcription factors, general transcription machinery components, and chromatin factors, ChIP can help in the functional annotation of the open chromatin regions identified by DNaseI HS mapping and FAIRE. Input data: As a background control experiment, we sequenced the input genomic DNA sample that was used for ChIP. Crosslinked chromatin is sheared and the crosslinks are reversed without carrying out the immunoprecipitation step. This sample is otherwise processed in a manner identical to the ChIP sample as described below. The input track is useful in revealing potential artifacts arising from the sequence alignment process such as copy number differences between the reference genome and the sequenced samples, as well as regions of poor sequence alignability. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf For each site, the maximum F-Seq Density Signal value has been calculated for each assay that was performed in that cell type. F-Seq employs Parzen kernel density estimation to create base pair scores (Boyle et al., 2008b). Significant regions, or peaks, were determined by fitting the data to a gamma distribution to calculate p-values. Contiguous regions where p-values were below a 0.05 (DNaseI HS, ChIP) or 0.1 (FAIRE) threshold were considered significant. See assay specific description pages ( Duke DNaseI HS, UNC FAIRE and UTA TFBS) for more details. A Fisher's Combined P-value for DNaseI HS and FAIRE was calculated using Fisher's combined probability test. First, a test statistic is calculated using the formula x^2 = -2*sum(ln(pi)) where pi are the p-values calculated for DNaseI HS and FAIRE. X2 follows a chi-squared distribution, thus a combined p-value can be assigned to this test statistic.
2012-09-12 | E-GEOD-40833 | biostudies-arrayexpress
Project description:The human body contains thousands of unique cell types, each with specialized functions. Cell identity is governed in large part by gene transcription programs, which are determined by regulatory elements encoded in DNA. To identify regulatory elements active in seven cell lines representative of diverse human cell types, we used DNase-seq and FAIRE-seq to map âopen chromatinâ. Over 870,000 DNaseI or FAIRE sites, which correspond largely to nucleosome depleted regions (NDRs), were identified across the seven cell lines, covering nearly 9% of the genome. The combination of DNaseI and FAIRE is more effective than either assay alone in identifying likely regulatory elements, as judged by coincidence with transcription factor binding locations determined in the same cells. Open chromatin common to all seven cell types tended to be at or near transcription start sites and encompassed more CTCF binding sites, while open chromatin sites found in only one cell type were typically located away from transcription start sites, and contained DNA motifs recognized by regulators of cell-type identity. As one example of its ability to identify functional DNA, we show that open chromatin regions bound by CTCF are potent insulators. We identified clusters of open regulatory elements (COREs) that were physically near each other and whose appearance was coordinated among one or more cell types. Gene expression and RNA Pol II binding data support the hypothesis that COREs control gene activity required for the maintenance of cell-type identity. This publicly available atlas of regulatory elements may prove valuable in identifying non-coding DNA sequence variants that are causally linked to human disease. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf
2011-06-29 | GSE30224 | GEO