Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Nucleosome repositioning links DNA (de)methylation and differential CTCF binding during stem cell development

ABSTRACT: During differentiation of embryonic stem cells, chromatin reorganizes to establish cell type specific expression programs. Here, we have dissected the linkages between DNA methylation (5mC), hydroxymethylation (5hmC), nucleosome repositioning and binding of the transcription factor CTCF during this process. By integrating MNase-seq and ChIP-seq experiments in mouse embryonic stem cells (ESC) and their differentiated counterparts with biophysical modeling, we find that the interplay between these factors depends on their large-scale genomic context. The mostly unmethylated CpG islands have a reduced nucleosome occupancy and are enriched in cell type-independent binding sites for CTCF. The few remaining methylated CpG dinucleotides are preferentially associated with nucleosomes. In contrast, outside of CpG islands most CpGs are methylated and their average density oscillates so that it is highest in the linker region between nucleosomes. Outside CpG islands binding of TET1, an enzyme that converts 5mC to 5hmC, is associated with labile, MNase-sensitive nucleosomes. Such nucleosomes are poised for eviction in ESCs and become stably bound in differentiated cells where the level of TET1 and 5hmCs goes down. In particular, this has a dramatic effect at variable CTCF sites enriched outside CpG islands, that are occupied by CTCF in ESCs but loose CTCF during differentiation. To rationalize this cell type dependent targeting of CTCF binding in competition with the histone octamer, we have developed a quantitative biophysical model, which allowed predicting differences in CTCF binding due to TET1/5hmC/5mC-dependent nucleosome repositioning. MNase-seq experiments for analysis of mononucleosomes were conducted as described previously (Teif et al. Nature Struct. Mol. Biol., 2012). In addition, a dinucleosome fraction also was gel purified and sequenced. Briefly, embryonic stem cells from 129P2/Ola mice were cultured in ESGRO complete medium (Millipore), harvested and resuspended in low salt buffer (10 mM Hepes, pH 8, 10 mM KCl, 0.5 mM DTT) at 4 M-BM-0C. After disruption of the cells with a douncer the nuclei were collected by centrifugation and washed once with the MNase Buffer (10 mM TrisM-bM-^@M-^SHCl, pH 7.5, 10 mM CaCl2), resuspended in the MNase Buffer and digested with 0.5 units MNase per microliter (Fermentas) and incubation for 6M-bM-^@M-^S11 minutes at 37 M-BM-0C. The MNase digestion was stopped by putting the samples on ice and adding EDTA to a concentration of 10 mM. After digestion with 0.1 M-BM-5g M-BM-5lM-bM-^@M-^S1 RNase A (Fermentas) and removal of protein by phenol and chloroform extraction, the DNA was ethanol precipitated and the resulting DNA pellet was dissolved in H2O. DNA fragments corresponding to mononucleosomes or dinucleosomes were separated on a 2 % agarose gel using an E-Gel electrophoresis system (Life Technologies). The libraries for sequencing were prepared according to the standard Illumina protocol. High-throughput paired-end sequencing of at least 50 bp read length was performed on the Illumina HiSeq 2000 platform at the DKFZ sequencing core facility in Heidelberg, Germany. We obtained about 150 million nucleosome positions per sequencing reaction. ChIP-seq experiments were conducted as described previously (Teif et al. 2012). For each sample, 1 x 106 cells were cross-linked with 1% PFA and cell nuclei were prepared using a swelling buffer (25 mM Hepes, pH 7.8, 1 mM MgCl2, 10 mM KCl, 0.1% NP-40, 1 mM DTT). Chromatin was sheared to mononucleosomal fragments. After IgG preclearance the sheared chromatin was incubated with 4 M-BM-5g of either H3K9me3 (Abcam ab8898) or H3K4me3 (Abcam ab8580) antibody over night. After washes with sonication (10 mM TrisM-bM-^@M-^SHCl, pH 8.0, 200 mM NaCl, 1 mM EDTA, 0.5% N-lauroylsarcosine, 0.1% NaM-bM-^@M-^Sdeoxycholate), high-salt-buffer (50 mM Hepes pH 7.9, 500 mM NaCl, 1mM EDTA, 1% Triton X-100, 0.1% NaM-bM-^@M-^Sdeoxycholate, 0.1% SDS), lithium buffer (20 mM TrisM-bM-^@M-^SHCl pH 8.0, 1 mM EDTA, 250 mM LiCl, 0.5% NP-40, 0.5% NaM-bM-^@M-^Sdeoxycholate) and 10 mM TrisM-bM-^@M-^SHCl, chromatin was eluted from the protein G magnetic beads and the crosslink was reversed over night. After RNase A and proteinase K digestion, DNA was purified and cloned in a barcoded sequencing library for the Illumina HiSeq 2000 sequencing platform (single reads of 50 bp length).

ORGANISM(S): Mus musculus

SUBMITTER: Vladimir Teif

PROVIDER: E-GEOD-56938 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Publications

Nucleosome repositioning links DNA (de)methylation and differential CTCF binding during stem cell development.

Teif Vladimir B VB Beshnova Daria A DA Vainshtein Yevhen Y Marth Caroline C Mallm Jan-Philipp JP Höfer Thomas T Rippe Karsten K

Genome research 20140508 8

During differentiation of embryonic stem cells, chromatin reorganizes to establish cell type-specific expression programs. Here, we have dissected the linkages between DNA methylation (5mC), hydroxymethylation (5hmC), nucleosome repositioning, and binding of the transcription factor CTCF during this process. By integrating MNase-seq and ChIP-seq experiments in mouse embryonic stem cells (ESC) and their differentiated counterparts with biophysical modeling, we found that the interplay between the ...[more]

PMID: 24812327

Similar Datasets

Project description:While the regulation of metabolic enzymes by oncogenic drivers or tumor suppressors has been intensively studied over recent years, our understanding of how metabolic processes directly regulate cell proliferation has remained fragmentary. Here we show how the alteration of metabolism directly affects cell cycle progression in cancer cells. We found that activation of the nuclear receptor peroxisome-proliferation activated receptor gamma (PPARM-NM-3), a transcriptional master regulator of lipid metabolism, inhibits the growth of lung adenocarcinoma cells by triggering a metabolic switch that inhibits pyruvate oxidation and reduces glutathione levels. These PPARM-NM-3-induced metabolic changes result in a marked increase of reactive oxygen species (ROS) levels that lead to rapid hypophosphorylation of retinoblastoma protein (RB) and cell cycle arrest. Both of these changes can be prevented by suppressing pyruvate dehydrogenase kinase 4 (PDK4) or M-NM-2-oxidation of fatty acids. Thus, we provide a mechanism that directly links metabolic changes to inhibition of cancer cell cycle progression by altering ROS levels. We generated PPARG-LAP BAC transgenic NCI-H2347 and NCI-H1993 cell lines using the BAC-transgenesis approach. Cells at 80% confluency (~1-1.5x107) were cross-linked with 1% formaldehyde for 10 minutes at 37M-BM-0C, and quenched with 125 mM glycine at room temperature for 5 minutes. The fixed cells were washed twice with cold PBS, scraped, and transferred into 1 ml PBS containing protease inhibitors (Roche). After centrifugation at 700 g for 4 minutes at 4M-BM-0C, the cell pellets were resuspended in 100 M-NM-<l ChIP lysis buffer (1% SDS, 10 mM EDTA, 50 mM Tris-HCl [pH 8.1] with protease inhibitors) and sonicated at 4M-BM-0C with a Bioruptor (Diagenode) (30 seconds ON and 30 seconds OFF at highest power for 12 minutes). The sheared chromatin with a fragment length of ~200 M-bM-^@M-^S 600 bp) was centrifuged at 10,000 g for 10 minutes at 4M-BM-0C). 100 M-NM-<l of the supernatant was used for ChIP or as input. A 1:10 dilution of the solubilized chromatin in ChIP dilution buffer (0.01% SDS, 1.1% Triton X-100, 1.2 mM EDTA, 167 mM NaCl 16.7 mM Tris-HCl [pH 8.1]) was incubated at 4M-BM-0C overnight with 6 M-NM-<g/ml of a goat anti-GFP (raised against His-tagged full-length eGFP and affinity-purified with GST-tagged full-length eGFP). Immunoprecipitations were carried out by incubating with 40 M-NM-<l pre-cleared Protein G Sepharose beads (Amersham Bioscience) for 1 hour at 4M-BM-0C, followed by five washes for 10 minutes with 1ml of the following buffers: Buffer I: 0.1% SDS, 1% Triton X-100, 2 mM EDTA, 20 mM Tris-HCl [pH 8.1], 150 mM NaCl; Buffer II: 0.1% SDS, 1% Triton X-100, 2 mM EDTA, 20 mM Tris-HCl [pH 8.1], 500 mM NaCl; Buffer III: 0.25 M LiCl, 1% NP-40, 1% deoxycholate, 1 mM EDTA, 10 mM Tris-HCl [pH 8.1]; twice with TE buffer [pH 8.0]. Elution from the beads was performed twice with 100 M-NM-<l ChIP elution buffer (1% SDS, 0.1 M NaHCO3) at room temperature (RT) for 15 minutes. Protein-DNA complexes were de-crosslinked by heating at 65M-BM-0C in 192 mM NaCl for 16 hours. DNA fragments were purified using QiaQuick PCR Purification kit (Qiagen) and eluted into 30 M-NM-<l H2O according to the manufacturerM-bM-^@M-^Ys protocol after treatment with RNase A and Proteinase K.

Project description:Polycomb repressive complex-2 (PRC2) is a histone methyltransferase required for epigenetic silencing during development and cancer. Long non-coding RNAs (lncRNAs) recruit PRC2 to chromatin, but the general role of RNA in maintaining repressed chromatin is unknown. ChIP-seq, combined with RNA-seq, indicating that PRC2 is also associated with active genes, but most of these are not regulated by PRC2. These results were complemented by in vitro binding assays measuring the binding constant of human PRC2 to various RNAs and find comparable affinity for human lncRNAs targeted by PRC2 and irrelevant transcripts from ciliates and bacteria. PRC2 binding is size-dependent, with lower affinity for shorter RNAs. These findings support a model in which promiscuous binding of PRC2 to RNA transcripts allows it to scan for target genes that have escaped repression, leading to maintenance of the repressed state. Such RNAs may also provide a decoy for PRC2. Cell culture: HEK293T/17 cells were cultured in DMEM with 10% FBS for no longer than 15 passages. ON-TARGETplus SMARTpool for human SUZ12 (Thermo Scientific, Dharmacon cat # L-006957-00-0005) was used to knockdown SUZ12 (siSUZ12) and ON-TARGETplus Non-targeting Pool (Dharmacon cat # D-001810-10-05) was used as a negative control (siCtrl). A total of 25 nM siRNA was transfected in 6-well dishes using LipofectamineM-bM-^DM-" RNAiMAX Reagent (Life Technologies, Invitrogen) following the manufacturerM-bM-^@M-^Ys recommendations. RNA-seq: Polyadenylated RNA was purified from 4 ug of RNA. cDNA libraries were prepared and double-stranded cDNA was fragmented using DNase I according to Illumina specifications, prior to adaptor ligation. Sequencing libraries were amplified and sequenced using an Illumina HiSeq 2000 sequencer. ChIP-seq: 30 million cells at 80% to 90% confluent culture were crosslinked in 1% v/v formaldehyde for 10 min, quenched in 150 mM glycine, washed with cold 1xPBS and harvested by scraping. Cells were lysed in Lysis Buffer (1% w/v SDS, 10 mM EDTA, 50 mM Tris-HCl pH 8.1) with 1x CompleteM-BM-. protease inhibitors (Roche). Cells were sonicated for 10 to 15 min using a BioruptorM-bM-^DM-" UCD-200 (Diagenode) with 30 sec pulses at maximum power. Lysates were diluted to 10 ml in IP Buffer (0.01% w/v SDS, 1.1% v/v Triton-X, 1.2 mM EDTA, 16.7 mM Tris-HCL pH 8.0, 167 mM NaCl) and 10 to 20 ng of antibodies were added and incubated overnight at 4 M-bM-^AM-0C with rotation. Antibodies were immunoprecipitated with 60 M-BM-5l protein G Plus/protein A Agarose Suspension (Calbiochem cat # IP05) and washed sequentially with 1 ml Low Salt Wash Buffer (0.1% w/v SDS, 1% v/v Triton X-100, 2 mM EDTA, 20 mM Tris-HCl pH 8.0, 150 mM NaCl), 1 ml High Salt Wash Buffer (0.1% w/v SDS, 1% v/v Triton X-100, 2 mM EDTA, 20 mM Tris-HCl pH 8.0, 500 mM NaCl), 1 ml LiCl Wash Buffer (0.25 M LiCl, 1% v/v Nonidet P-40, 1% w/v deoxycholate, 1 mM EDTA, 10 mM Tris-HCl pH 8.0) and 1 ml TE buffer (Qiagen). DNA was eluted with 0.4 ml of 0.1 M NaHCO3 and 1% w/v SDS. Eluent was transferred into a new tube and NaCl was added to a final concentration of 200 mM. Crosslinks were reversed by incubation at 65 M-bM-^AM-0C for 2 hours. Next, proteins and RNA were digested by adding 33 M-BM-5l of Digestion Reagent (0.6 M Tris-HCl pH 6.5, 152 mM EDTA, 61 ng/ml RNase A (Invitrogen cat # AM2274) and 0.61 mg/ml Proteinase K (NEB cat # P8102)) following by 1 hour incubation at 37 M-bM-^AM-0C. DNA was extracted by phenol:chloroform and ethanol precipitated. DNA was resuspended in Milli-Q pure water and concentration was measured using QubitM-bM-^DM-" (Invitrogen). At least 10 ng of recovered DNA was used to synthesize sequencing libraries using the ChIP-seq Sample Preparation kit (Illumina). Between 6 and 10 pmoles were used for sequencing on the HiSeq2000 sequencer.

Project description:Neuroblastoma (NB) is the most frequent extracranial solid tumour of childhood. Clinical courses are highly variable, ranging from spontaneous regression/maturation to rapid progression despite intensive multimodal therapy. The estimation of 5-year event free survival in high-risk patients of only about 40 % stresses an importance of novel therapeutic strategies. A number of iron chelators have demonstrated marked in vitro and in vivo anti-tumor activity and are currently being developed as novel anti-cancer agents. Therefore, the potential antitumor effect of iron chelators in NB cancer was investigated. Among the compounds tested, ciclopirox olamine (CPX) was shown to be one of the most effective intracellular iron chelators in NB cells. To unveil the molecular mechanisms underlying the effects of CPX on viability of NB cells, microarray analysis was performed in CHP134 control cells and cells treated with 5 M-BM-5M CPX for 90 minutes. Inclusion of both total RNA (reflecting transcriptional status of the cells) and polysomal RNA (approximating the proteomic representation of the cells) provided us with a deeper understanding of changes in the cells upon CPX treatment. Keywords: ciclopirox olamine, iron chelator, neuroblastoma, translatome profiling, transcriptome profiling. Keywords: ciclopirox olamine, iron chelator, neuroblastoma, translatome profiling, transcriptome profiling, polysomal profiling, polysomal RNA, translational control, translational profiling, polysome profiling Microarray analysis was performed to enable a comprehensive view of the changes in the transcriptional and translational status of the cells in response to the treatment with an iron chelator CPX. Polysomal RNA and total RNA were isolated from vehicle-treated CHP134 cells and CHP134 cells treated with 5 M-BM-5M CPX for 90 minutes. Each condition is represented by three biological replicates, i.e. the experiment was repeated starting each time from cells seeding yielding an independent RNA sample. In total, 12 samples corresponding to 4 conditions were subjected to microarray analysis.

Project description:Glioblastoma stem cells (TS-543) were harvested and cross-linked with 1% formaldehyde for 10 mins at room temperature. The cells were lysed using SDS Lysis buffer for ChIP (1% SDS, 10 mM EDTA, 50 mM Tris-HCl pH 8). The lysate was then sonicated for 25 cycles at 30% amplitude (15 s ON and 45 s OFF). The sonicated samples were then diluted in ChIP dilution buffer (0.01% SDS, 1% Triton-X-100, 1.2 mM EDTA, 16.7 mM Tris–HCl pH 8, 167 mM NaCl) and used for the immunoprecipitation with H3K27ac (Abcam, Ab4729), H2AZ (Active motive, cat#39113) and H3K27ac (Abcam cat#ab8580). After an over-night incubation with antibody, the bound DNA was washed sequentially with low salt wash buffer (0.1% SDS, 1% Triton X 100, 2 mM EDTA, 20 mM Tris–HCl pH 8, 150 mM NaCl), high salt wash buffer (0.1% SDS, 1% Triton X-100, 2 mM EDTA, 20 mM Tris–HCl pH 8, 500 mM NaCl), LiCl wash buffer (0.25 M LiCl, 1% NP40, 1%deoxycholate, 1 mM EDTA, 10 mM Tris–HCl pH 8) and TE wash buffer (10 mM Tris–HCl pH 8, 1 mM EDTA) to remove non-specific sequences and eluted in the elution buffer (84 mg NaHCO3, 1 ml 10% SDS, 9 ml H2O). Then the samples were reverse cross-linked using NaCl at 65°C overnight. The eluted DNA was purified and used for library preparation. Library preparation was performed as previously described as described in Bowman et al. BMC Genomics 2013. Briefly, end repair with NEBNext End Repair enzyme (NEB, E6050) and clean-up with 2.4x volume AMPure XP beads (Beckman Coulter, A63880). A-tailing with Klenow Fragment (NEB, M0212) and purified with 2.4x volume AMPure XP beads. Adapter ligation reactions contained annealed universal adapter and T4 rapid ligase (NEB, B0202) and clean-up with 1.8x volume AMPure XP beads. Chromatin was amplified using KAPA Real-time Library Amplification Kit (KAPABIOSYSTEMS, KK2701) with universal primer and barcoded primer. Amplified chromatin was purified with QIAquick Gel Extraction Kit (Qiagen) and sequenced paired-end with Illumina NextSeq 500.

Dataset Information

Nucleosome repositioning links DNA (de)methylation and differential CTCF binding during stem cell development

Publications

Nucleosome repositioning links DNA (de)methylation and differential CTCF binding during stem cell development.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets