Genome-wide nucleosome positioning during embryonic stem cell development [ChIP-Seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
SUBMITTER: Vladimir Teif
PROVIDER: E-GEOD-40951 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Publications
Genome-wide nucleosome positioning during embryonic stem cell development.
Teif Vladimir B VB Vainshtein Yevhen Y Caudron-Herger Maïwen M Mallm Jan-Philipp JP Marth Caroline C Höfer Thomas T Rippe Karsten K
Nature structural & molecular biology 20121021 11
We determined genome-wide nucleosome occupancies in mouse embryonic stem cells and their neural progenitor and embryonic fibroblast counterparts to assess features associated with nucleosome positioning during lineage commitment. Cell-type- and protein-specific binding preferences of transcription factors to sites with either low (Myc, Klf4 and Zfx) or high (Nanog, Oct4 and Sox2) nucleosome occupancy as well as complex patterns for CTCF were identified. Nucleosome-depleted regions around transcr ...[more]
Similar Datasets
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.
2021-09-05 | GSE152862 | GEO
Project description:Identification and characterization of HP1BP3 (a human histone H1 homologue) as a novel chromatin retention factor essential for the co-transcriptional processing of pri-miRNA. We generated BAC transgenic cells at 80% confluency (~1x107) were cross-linked with 1% formaldehyde for 10 minutes at 37°C, 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 4°C, the cell pellets were resuspended in 100 μl ChIP lysis buffer (1% SDS, 10 mM EDTA, 50 mM Tris-HCl [pH 8.1] with protease inhibitors) and sonicated at 4°C with a Bioruptor (Diagenode) (30 seconds ON and 30 seconds OFF at highest power for 15 minutes). The sheared chromatin with a fragment length of ~200 â 600 bp) was centrifuged at 20,000 g for 15 minutes at 4°C). 100 μl 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 4°C overnight with 6 μg/ml of a goat anti-GFP (raised against His-tagged full-length eGFP and affinity-purified with GST-tagged full-length eGFP). Immunoprecipitation was carried out by incubating with 40 μl pre-cleared Protein G Sepharose beads (Amersham Bioscience) for 1 hour at 4°C, 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 μl 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 65°C in 192 mM NaCl for 16 hours. DNA fragments were purified using QiaQuick PCR Purification kit (QIAGEN) and eluted into 30 μl H2O according to the manufacturerâs protocol after treatment with RNase A and Proteinase K.
2016-07-24 | E-GEOD-77854 | biostudies-arrayexpress
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.
2014-09-25 | E-GEOD-58382 | biostudies-arrayexpress
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.
2013-09-28 | E-GEOD-50177 | biostudies-arrayexpress
Project description:For modified iCLIP experiment, 4SU was used for crosslinking as described in published protocol (citation is bellow) and the RNase conditions were optimised to ensure efficient RNase I-dependent fragmentation. In detail, HEK293T cells were grown on 10 cm 2 dishes, incubated for 8 h with 100 M 4SU and crosslinked with 2x 400mJ/cm 2 365nm UV light. Protein A Dynabeads were used for immunoprecipitations (IP). 80 l of beads were washed in iCLIP lysis buffer (50mM Tris-HCl pH 7.4, 100 mM NaCl, 1% NP-40, 0.1% SDS, 0.5% sodium deoxycholate). For the preparation of the cell lysate, 2 million cells were lysed in 1 ml of iCLIP lysis buffer (50 mM Tris-HCl pH 7.4, 100 mM NaCl, 1% NP-40, 0.1% SDS, 0.5% sodium deoxycholate) buffer, and the remaining cell pellet was dissolved in 50 L MSB lysis buffer (as above). After the pellet had dissolved, the mixture was diluted with CLIP lysis buffer to 1000 l and an additional centrifugation was performed. Lysates were pooled (2ml total volume) and incubated with 4 U/ml of RNase I and 2 l antiRNase (1/1000, AM2690, Thermo Fisher) at 37C for 3 min, and centrifuged. We took care to prepare the initial dilution of RNase in water, since we found that RNase I gradually loses its activity when diluted in the lysis buffer. 1.5 ml of the supernatant was then added to the beads and incubated at 4C for 4 h. The rest of the protocol was identical to the published protocol (see bellow). Huppertz I, Attig J, D'Ambrogio A, Easton LE, Sibley CR, Sugimoto Y, Tajnik M, Knig J, Ule J: iCLIP: protein-RNA interactions at nucleotide resolution. Methods 2014, 65:274-287.
2016-11-24 | E-MTAB-5027 | biostudies-arrayexpress
Project description:Cells were washed with cold PBS twice and scraped from the plates, then centrifuged at 1000 rpm for 5 min to pellet cells. Washed cells were lysed with 400 L of cell lysis buffer (10 mM Tris-HCl pH7.5, 150 mM NaCl, 0.15% NP-40 and proteinase inhibitor cocktail) and incubated on ice for 10 min. The suspension was carefully add at the top of sucrose buffer (10 mM Tris-HCl pH7.5, 150 mM NaCl, 24% sucrose), and centrifuged at 3200g for 10 min to collect nuclear pellets. Pellets were resuspended in 250 L of Glycerol buffer (20 mM Tris-HCl pH7.5, 75 mM NaCl, 0.5 mM EDTA pH8.0, 50% glycerol), then then immediately add 250 μl Nuclear lysis buffer (10 mM Tris-HCl pH7.5, 300 mM NaCl, 7.5 mM MgCl2, 0.2 mM EDTA pH8.0, 1% NP-40, 1M urea). Mix by vortexing for 4 s and incubate on ice for 2 min. Centrifuge the lysate at 13,000 × g for 2 min to precipitate the chromatin–RNA complex. Briefly rinse the chromatin pellets with PBS-EDTA. RNA was extracted with Trizol reagent. RNA libraries were prepared according to manual of SMARTer smRNA-Seq Kit for Illumina (Clontech, 635031).
2019-10-15 | GSE134103 | GEO
Project description:Samples were purchased from Clontech as mRNA. Hybridization material was generated through a random-priming amplification procedure (RP-AMP) using primers with a random sequence at the 3' end and a fixed motif at the 5' end. shDNP256 (first strand synthesis): 5'- TAG ATG CTG TTG NNN NNN NNN -3' shT7N9 (second strand synthesis): 5'- ACT ATA GGG AGA NNN NNN NNN -3' 1.5 g of mRNA was reverse-transcribed with Superscript II and the DP256 random primer for 20 minutes at 42 C (10 mM DTT, 50 mM Tris-HCl pH 8.3, 75 mM KCl, 8 mM MgCl2, 0.5 mM dNTPs, 5 U/ l Superscript II). The RNA was degraded with the addition of 20 l volume of 0.5N sodium hydroxide and 0.25 M EDTA for 20 minutes at 65 C. The single stranded cDNA was purified using a commercial kit (Qiagen Qiaquick). The resulting product of single stranded cDNA was placed in its entirety in a second strand reaction. Second strand synthesis reactions utilized shT7N9 random primer and the Klenow fragment of DNA polymerase utilizing standard reaction conditions (37 C for 60 minutes, 0.2 mM DTT, 2.1 mM Tris-HCl pH 7.9, 2.1 mM MgCl2, 10.7 mM NaCl, 1.07 mM dNTPs, 0.1U/ l Klenow), followed by another Qiaquick purification. Multiple polymerase chain reactions were run using 0.15 g of double stranded DNA and standard reaction conditions. Amplification was achieved using 10 cycles of PCR with the DP256 and T7 primers (20 mM Tris-HCl pH 8.4, 50 mM KCl, 0.01 mM dNTPs, 1.5 mM MgCl2, 0.01 U/ l Taq Polymerase) DP256: 5'- GTT CGA GAC CTC TAG ATG CTG TTG -3' T7: 5'- AA TTA ATA CGA CTC ACT ATA GGG AGA -3' followed by Qiaquick purification. Further amplification was achieved using in vitro transcription reactions with X0.5 g dsDNA and T7 RNA Polymerase (7.5 mM DTT, 40 mM Tris-HCl pH 7.5, 14.25 mM MgCl2, 10 mM NaCl, 2 mM Spermidine, 125 U/ml RNAguard, 2.5 mM dNTPs, 15 U/ml IPPase, 25kU/ml T7 Polymerase) for 16 hours at 42 C. The cRNA was purified (RNeasy) and reverse transcribed using Superscript and random 9-mers and amino-allyl dUTP (42 C for 20 minutes, 10 mM DTT, 50mM Tris-HCl pH 8.3, 75 mM KCl, 8 mM MgCl2, 0.5 mM dNTPs, 0.5 mM aa-dUTP, 5 U/ l Superscript II). The cDNA for each channel was covalently coupled separately with Cy5 and Cy3 monoreactive fluors, respectively, in 1M sodium bicarbonate, pH 9.0, followed by quenching with 4.0 M hydroxylamine. The Cy5 and Cy3 labelled cDNAs were purified with a QIAquick PCR purification kit and the percentage dye incorporation and total cDNA yield was determined spectrophotometrically. Cy5 and Cy3 labelled cDNAs were combined and added to 2 mls 30% formamide with Herring Sperm DNA for hybridization to the microarray. Further details can be found in Castle et al., Genome Biol 2003;4(10):R66, http://genomebiology.com/2003/4/10/R66 , Roberts CJ et al., Science 2000, 287:873-880, and Schadt, Edwards, et al., unpublished. Normalization of single channel data is described in Ying, et al., "Identification of Chromosomal Regions Containing Transcribed Sequences Using Microarrays and Computational Methods" , 2003 Proceedings of the American Statistical Association, Biopharmaceutical Section [CD-ROM], Alexandria, VA: American Statistical Association, 2003. Briefly, an invariant set of probes was selected based on their intensity ranks. Then, a LOESS regression model was fit for Cy5 vs. Cy3 intensities for all probes in the invariant set. Finally, for all probes on the array the Cy5 intensities were normalized to the corresponding Cy3 intensities using prediction values from the regression model. Note that the normalized intensity values given here were used for all analyses reported in the accompanying paper. The ratio values reported here were not used for the analysis described in the manuscript and are not calculated from the normalized intensity values given below. Keywords: other
2004-03-04 | GSE1097 | GEO
Project description:U2OS osteosarcoma cells were cultured in Dulbecco's modified Eagle's medium (DMEM, Gibco) and Raji B-cells in RPMI 1640 medium (Gibco) supplemented with 10% fetal calf serum (FCS, Bio&Sell), 2 mM L-glutamine (Gibco), 100 U/mL penicillin (Gibco), and 100 µg/mL streptomycin (Gibco) at 37°C at 8% or 5% CO2, respectively. Chromatin immunoprecipitation for ChIP-seq: Cells were crosslinked using a formaldehyde containing solution (10mM NaCl, 0,1mM EDTA pH 8, 0,05mM EGTA pH 8, 5mM HEPES pH 7.8 and 1% formaldehyde) for 10 minutes at 20°C, the reaction was quenched by the addition of glycin to a final concentration of 250uM for 5 minutes. Crosslinked cells were collected and washed twice with PBS before snap freezing in liquid nitrogen and storage at -80°C until subsequent use. Prior to sonication, the crosslinked cells were resuspended in lysis buffer (50mM Hepes pH 7.5, 140mM NaCl, 1mM EDTA pH 8, 10% glycerol, 0.75% NP-40, 0.25% Triton X-100, 1X protease inhibitor cocktail) at 4°C for 20 minutes. Nuclei were collected by centrifugation and washed in a second buffer (200mM NaCl, 1mM EDTA pH 8, 0.5mM EGTA pH 8, 10mM Tris pH 8, 1X protease inhibitor cocktail) for 10 minutes at 4°C then collected by centrifugation and resuspended in the shearing buffer (1mM EDTA pH 8, 0.5mM EGTA pH 8, 10mM Tris pH 8, 100mM NaCl, 0.1% Na-Deoxycholate, 0.5% N-lauroylsarcosine, 1X protease inhibitor cocktail). Sonication was carried out in a Bioruptor Pico ultrasounds water bath (Diagenode B01060001) for 30 cycles of 30 sec ON and 30 sec OFF pulses in 4°C water. Sonicated extracts were centrifuged at high speed in the presence of 0,1% of Triton X-100 and snap frozen in liquid nitrogen then stored at -80°C until subsequent use. Prior to ChIP, the ZNF768 mAb was coupled to protein-G coated magnetic beads (Dynabeads, life technologies) by incubation in 0,5% BSA PBS overnight at 4°C. Pre-coated beads were then washed and incubated with the sonicated chromatin extracts, the ChIP was carried out overnight at 4°C on a rotating wheel. The equivalent of 10 × 107 cells sonicated extract was used for each ZNF ChIP experiment for both cell lines. After incubation, the beads were washed 7 times with Wash buffer (50mM Hepes pH 7.6, 500mM LiCl, 1mM EDTA pH 8, 1% NP-40, 0.7% Na-Deoxycholate, 1X protease inhibitor cocktail) followed by one wash with TE-NaCl buffer (10mM Tris pH 8 and 1mM EDTA pH 8, 50mM NaCl). Immunoprecipitated chromatine was eluted by two sequential incubations with 100µl Elution buffer (50mM Tris pH 8, 10mM EDTA pH 8, 1% SDS) at 65°C for 15 minutes. The two eluates were pooled and incubated at 65°C for 12 hours to reverse-crosslink the chromatin followed by treatment with RNase A (0.2µg/mL) at 37°C for two hours and Proteinase K (0.2µg/mL) at 55°C for two hours. The DNA was isolated by phenol:chloroform: isoamylalcohol (25:24:1 pH 8) extranction followed by Qiaquick PCR Purification (Qiagen, Germany) and quantified with Qubit DS DNA HS Assay (ThermoFisher Scientific, USA). At least 1ng of ChIP DNA was used to prepare sequencing library with Illumina ChIP Sample Library Prep Kit (Illumina, USA) with a few optimizations to the protocol. The ChIP DNA was size selected using Ampure beads (Life technologies) to enrich for fragments < 400Bp prior to end-repair, 3’end adenylation and adapter ligation. Library fragments were then directly amplified by 10 cycles of PCR.
2018-10-29 | GSE111879 | GEO
Project description:Flag-YBX1 overexpressed T24 cells pellets were resuspended with 2 volume of lysis buffer (150 mM KCl, 10 mM HEPES pH 7.6, 2 mM EDTA, 0.5% NP-40, 0.5 mM DTT, 1:100 protease inhibitor cocktail, 400 U/ml RNase inhibitor), and incubated at 4 °C for 30 min with rotation. Then the lysate was centrifuged at 15 000 g for 20 min. Before incubating the lysate with Flag beads, 100ul were taken as input. The anti-Flag M2 magnetic beads (Sigma, 10 μl per mg lysate) were washed with NT2 buffer (200 mM NaCl, 50 mM HEPES pH 7.6, 2 mM EDTA, 0.05% NP-40, 0.5 mM DTT, 200 U/ml RNase inhibitor) four times. Cell lysate was mixed with M2 beads and incubated at 4 °C for 4 h with rotation. The beads were washed two times with 1 ml ice-cold NT2 buffer. Then the beads were subject to Micrococal nuclease (NEB) digestion (1:1 000 000 dilution) for 8 min at 37 °C. The beads were cooled on ice immediately for 5 min and washed two times with 1 ml ice-cold 1× PNK+EGTA buffer (50 mM Tris-HCl pH 7.5, 20 mM EDTA, 0.05% NP-40, 200 U/ml RNase inhibitor) and two times with 1 ml ice-cold 1× PK buffer (50 mM NaCl, 100 mM Tris-HCl pH 7.5, 10 mM EDTA, 0.2% SDS, 200 U/ml RNase inhibitor). Then the beads were digested with 200 μl pre-heated (20 min at 50 °C) Proteinase K and RNAs were extracted with an equal volume of Acid-Phenol: Chloroform, pH 4.5 (Ambion). The RNAs were subjected to rRNA removal and Bisseq. The libraries were sequenced on the Illumina HiSeq X-Ten platform at Novogene (Tianjin, CA) with paired-end 150 bp read length.The m5C sites were called using meRanCall from meRanTK (FDR < 0.01).
2019-07-02 | GSE133625 | GEO
Project description:The modified iCLIP protocol is based on the previously described protocol (Huppertz et al., 2014) with modifications that enable the definition of readthrough cDNAs. HeLa cells were crosslinked with 0.15mJ/cm2 254nm UV light. Protein G Dynabeads were used for immunoprecipitations (IP). For each IP, 100 l of beads were washed in iCLIP lysis buffer (50mM Tris-HCL pH 7.4, 100mM NaCl, 1% NP-40, 0.1% SDS, 0.5% sodium deoxycholate), and incubated with the anti-eIF4A3 antibody or polyclonal mAb BB7 serum anti-PTBP1. To prepare the cell lysate, the cells were lysed with 1 mL iCLIP lysis buffer (final concentration 2mg/mL), sonicated (Bioruptor, 5x5 sec on/off), incubated with RNase I (1-2 x10-3 U/mL for eIF4A3) at 37C for 3 min, and centrifuged. After the pellet had dissolved, the mixture was diluted with H2O to 1000 L and an additional centrifugation was performed. The supernatant of the iCLIP lysis buffer (1 mL) and the MSB lysis buffer (1 ml) were combined and added to the antibody-coupled beads, which were then rotated at 4C for 2 h (final urea concentration 175 mM). The beads were then washed with high-salt washing buffer (50mM Tris-HCL pH 7.4, 1M NaCl, 1% NP-40, 0.1% SDS, 0.5% sodium deoxycholate). After the first round of washes, the library was split into 10%, which were radioactively labelled (according to the basic iCLIP protocol), and 90%, which proceed through 3 adapter addition, an additional phosphorylation (0.2 l PNK, 0.4 l cold ATP (1mM), 0.4 l 10x PNK buffer, 3 l water) and a 5 marker ligation (6 l water, 5 l 4X ligation buffer, 2 l RNA ligase, 1 l RNasin, 2 l 5 marker (100 M), 4 l PEG400). The sequence of the 5 marker is CAGUCCGACGAUC, which corresponds to the Illumina short RNA 5 Adapter (RA5), part #15013205; this sequence is not complementary to the primers used for amplification of iCLIP cDNA libraries (Huppertz et al., 2014). We then produced sequence reads of 120 nt using the Illumina HiSeq platform for eIF4A3 iCLIP. The rest of the protocol was carried out as previously described (Huppertz et al., 2014). Huppertz, I., Attig, J., D'Ambrogio, A., Easton, L.E., Sibley, C.R., Sugimoto, Y., Tajnik, M., Konig, J., and Ule, J. (2014). iCLIP: protein-RNA interactions at nucleotide resolution. Methods 65, 274-287.
2016-11-24 | E-MTAB-4000 | biostudies-arrayexpress