Genome wide mapping of native R-loops using a targeted nuclease approach in HCT116 cells after DDX41 siRNA knockdown (MapR)
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE183081 | GEO | 2021/11/17
REPOSITORIES: GEO
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Project description:Purpose: Investigation of genome-wide changes in R-loop levels after knockdown of DDX41 U2OS cells in comparison to a control knockdown. Method: Concanavalin A-coated beads were activated in Binding Buffer (20 mM Hepes-KOH pH 7.9, 10 mM KCl, 1mM CaCl2, 1 mM MnCl2). 5*105 U2OS cells were washed twice with Wash Buffer (Hepes-NaOH pH7.5, 150 mM NaCl, 0.5 mM Spermidine, 1 mM protease inhibitor) at room temperature and afterwards immobilized on the activated beads in 50 µl Wash Buffer containing 0.05% Digitonin. Either pA-MNase or RHΔ-MNase were added to the cells overnight at 4°C on a rotating wheel. After three washes with Wash Buffer containing 0.05% Digitonin, samples resuspended in 100 µl Dig-Wash-Buffer were equilibrated on ice. Activity of the MNase was triggered by adding 2mM CaCl2 to the samples for 30 minutes. 2x Stop Buffer (68 µl 5M NaCl, 40 µl 0.5 M EDTA, 20 µl 0.2 M EGTA, 10 µl 5% digitonin, 5 µl 10mg/ml RnaseA, 20 pg/ml spike-in Drosophila DNA (Active Motif)) was mixed with the samples to stop the reaction. Chromatin fragments were released by incubating the samples for 20 minutes at 37°C and centrifugation at 16.000×g for 10 minutes at 4°C. Supernatants were incubated at 70°C in the presence of 0.1% SDS and 5 µg proteinase K. Before library preparation, the DNA was recovered by phenol-chloroform extraction Results: We were able to map R-loop dynamics genome-wide in U2OS cells in biological triplicates. MapR signal was significantly increased around the transcription start site in the absence of DDX41 and decreased after treatment with ActinomycinD.
2021-05-04 | GSE168170 | GEO
Project description:Purpose: Investigation of DDX41 chromatin binding sites in U2OS cells Method: Expression of DDX41-GFP was induced for 48 hours before crosslinking using 1µg/ml docycycline. Control cells were not induced with doxycline. Cells were mildly crosslinked using 1% FA for 2 min at RT. Concanavalin A-coated beads were activated in Binding Buffer (20 mM Hepes-KOH pH 7.9, 10 mM KCl, 1mM CaCl2, 1 mM MnCl2).1*10^6 U2OS cells were washed twice with Wash Buffer (Hepes-NaOH pH7.5, 150 mM NaCl, 0.5 mM Spermidine, 1 mM protease inhibitor) at room temperature and afterwards immobilized on the activated beads in 1 ml Wash Buffer. Cells were permeabilized with 0.05% digitonin in Wash buffer for 4 min at RT. 1 µg Nanobody-GFP-MNase (in-house protein production, PMID:25362362) binding was performed at 4°C for 30 min in 0.05% digitonin-Wash buffer. After 2x washing, the MNase was activated by adding 3mM CaCl2 on ice for 30 min. 2x Stop Buffer (68 µl 5M NaCl, 40 µl 0.5 M EDTA, 20 µl 0.2 M EGTA, 10 µl 5% digitonin, 5 µl 10mg/ml RnaseA, )) was mixed with the samples to stop the reaction. Chromatin fragments were released by incubating the samples for 20 minutes at 37°C and centrifugation at 16.000×g for 10 minutes at 4°C. Supernatants were incubated at 70°C in the presence of 0.1% SDS and 5 µg proteinase K. Before library preparation, the DNA was recovered by phenol-chloroform extraction Results: We succesfully mapped DDX41 binding sites on cromatin in U2OS cells. DDX41 preferentially binds in the promoter region of genes.
2021-11-17 | GSE183083 | GEO
Project description:Approximately 3 × 105 NPCs sorted for Sox2-eGFP were mixed with 3 × 104 Drosophila S2 cells per reaction. We performed CUT&RUN using the protocol developed by the Henikoff lab (Skene and Henikoff, 2017). In brief, Bio-Mag®Plus Concanavalin-A (Con A) coated beads (Bangs Laboratories BP531) were washed and activated with Binding buffer. Nuclei of NPCs with S2 spike-in were gently prepared (see Subcellular Protein Extraction section). Activated Con A beads and nuclei were then mixed and rotated for 5 min at room temperature. They were then blocked with Digitonin block buffer for 5 min at room temperature. 0.5-1 μg of primary antibody with 0.25 μg Spike-in antibody (Active Motif 61686) diluted in Digitonin block buffer was added to the bead-nuclei mixture and incubated for 3 hours (histone marks) or O/N (the rest) at 4 °C. Beads were washed three times with Digitonin block buffer and incubated with pA-MNase for 1 hour at 4 °C. Beads were washed three times with Wash buffer and incubated in Wash buffer for 10 min on ice. The pA-MNase was activated by incubating the beads with 2 mM CaCl2 for 25 min on ice and quenched by adding the Stop buffer. DNA was released from the beads by incubating them for 30 min at 37 °C and collected by centrifugation at 16,000 x g for 5 min at 4 °C. DNA was then isolated by using a phenol/chloroform extraction method.
2023-07-12 | GSE212444 | GEO
Project description:3x107 cells were harvested and washed in 30 ml cold 1x TDB. The pellet was resuspended in 300 µl permeabilization buffer with protease inhibitors, 3 µl of 4 mM digitonin was added and incubated for 5 minutes at RT. The cells were pelleted, resuspended in 600 µl isotonic buffer with protease inhibitors and split in two samples, containing 1x107 and 2x107 cells, respectively. The transposition reaction was performed by adding 50 µl of transposition mix to the pellet (25 µl TD (2x reaction buffer from Nextera kit), 25 µl TDE1 (Tn5 transposase from Nextera kit), 22.5 µl nuclease-free water) and incubation for 30 minutes at 37 °C. For the gDNA control, 200 ng of gDNA was treated in the same manner. The DNA samples were purified using Qiagen MinElute PCR Purification Kit and eluted in 10 µl EB (10 mM Tris-HCl, pH 8). The transposed DNA fragments were amplified using the NEBNext® High-Fidelity 2X PCR Master Mix (M0541) supplied with 2.5 µl of 25 µM barcoded primers and amplification for 13 cycles. The libraries were purified using AMPure XP beads (Beckman Coulter) following the manufacturer’s instructions. The library fragment sizes between 150 and 1000 bp were purified from a 6% polyacrylamide gel. Paired-end 76 bp sequencing was carried out using the Illumina NextSeq system with a mid-output NextSeq 500/550 kit according to the manufacturer’s instructions.
2018-08-24 | GSE118902 | GEO
Project description:Purpose: to identify the binding sites for BATF2 in HSCs during M. avium infection, we conducted CUT&RUN sequencing of the HSCs from infected WT mice using an anti-BATF2 antibody. We used an anti-IgG antibody as a control to exclude noise and nonspecific binding and an anti-H3K27ac to assess open chromatin Methods: 10,000-50,000 HSCs (CD45.1/CD45.2 KL CD150+ CD48-) into HBSS from1-month infected WT mice (n=10-12 per group). CUT&RUN sequencing was performed with modified methods as previously described (Henikoff et al., 2020; Skene et al., 2018). 50,000 HSCs (LK CD150+, CD48-) were sorted pools of naïve or 1-month (M. avium) infected WT mice for CUT&RUN sequencing (N=7-8). Cells were washed with Wash Buffer (50mL total with 20 mM HEPES pH 7.5, 150mM NaCl, 0.5 mM Spermidine, and one Roche Complete protein inhibitor tablet) and bound to Concanavalin A-coated magnetic beads (Bang Laboratories L200731C) for 15 minutes room temperature. Sample slurries were magnetically separated, washed, and incubated with primary antibody diluted in wash buffer containing 0.05% digitonin (Dig Wash) overnight at 4 °C. Slurries were then magnetically separated and washed with Dig Wash three times and then incubated with protein A-MNase (pA-MN, Epicypher 15-1016) for 1 hour at 4 °C. Slurries were magnetically separated and washed, resuspended in 200uL Dig Wash, and placed on an iced heating block. 2uL of 2mM CaCl2 was added to catalyze the pA-MN reaction and digestion. After 45 minutes, one equal volume of Stop Buffer (340mM NaCl, 20 mM EDTA, 4 mM EGTA, 0.05% Digitonin, 0.05 mg/mL glycogen, 5 ug/mL RNase A, 2 pg/mL heterologous spike-in DNA) was added to end the reaction, and sample slurries were then incubated for 30 minutes at 37 °C to release fragments and then magnetically separated. The supernatant was collected, and DNA was purified via phenol-chloroform extraction and ethanol precipitation. Samples were resuspended in molecular-grade water after ethanol precipitation. DNA was quantified with Qubit 2.0 DNA HS Assay (ThermoFisher, Massachusetts, USA) and quality was assessed by Tapestation High sensitivity D1000 DNA Assay (Agilent Technologies, California, USA). Library preparation was performed using the KAPA Hyper Prep kit (Roche, Basel, Switzerland) according to the manufacturer’s recommendations. Library quality and quantity were assessed with Qubit 2.0 DNA HS Assay (ThermoFisher, Massachusetts, USA), Tapestation High Sensitivity D1000 Assay (Agilent Technologies, California, USA), and QuantStudio ® 5 System (Applied Biosystems, California, USA). Illumina® 8-nt dual-indices were used. Equimolar pooling of libraries was performed based on QC values and sequenced on an Illumina® NovaSeq (Illumina, California, USA) with a read length configuration of 150 paired-end (PE). Antibodies used were anti-BATF2, Rabbit-anti mouse IgG (Jackson ImmunoResearch 315-005-003), and Rabbit anti-H3K27ac (Cell Signaling Technologies 8173T). PE reads were aligned to mm10 using Bowtie2 version 2.4.5. MACS2 version 2.2.7.1 was used to call peaks and CUT&RUN IgG was used as a negative control. Results: We found binding of BATF2 at cis-elements of ccr5, ifngr2 (interferon gamma receptor 2), ly6c1, and ccl28 genes (Figure 7C). The locations were highly aligned with accessible chromatin positions marked by H3K27ac, suggesting that BATF2 enhanced gene expression in response to infection. The observations were aligned with our RNA-seq analysis of gene expression in WT or Batf2 KO HSCs in the presence or absence of M. avium infection, as ccr5, ifngr2, ly6c1, and ccl28 were more effectively induced in WT compared to Batf2 HSCs during M. avium infection (Figure S5B). Conclusion: BATF2 interacts with regulatory elements in IFN response genes and facilitates increased expression in response to infection
2023-01-19 | GSE206276 | GEO
Project description:Goal of experiment: Identification of differentially expressed immune genes from male and female BWF1 lupus-prone mice. (Female incidence is higher than male--attempting to find sex hormone regulated genes that may contribute to this difference). Whole spleen was taken from pre-lupus (4 months old) BWF1 (females are lupus-prone) male and female mice. Preparation of cDNA. Double-stranded cDNA was synthesized from purified RNA. The first strand was synthesized by incubating 5 μg of RNA with 100 pg/ml T7-(dT)24 primer (HPLC purified DNA primer sequence: 5’-GGCCAGTGAATTGTAATACG ACTCACTATAGGGAGGCGG-(dT)24 -3’ Genset Corp, San Diego, CA) at 70°C for 10 minutes. Samples were incubated for 1 hour at 42°C with the following mix: 1X first strand buffer, 10 mM dithiothreitol, 500 μM each dNTP, 200 U SuperScript II in diethylpyrocarbonate (DEPC)-treated water up to 20 μl. Second strand synthesis was performed by incubating the first strand with the following mix for 2 hours at 16°C: 1X second strand reaction buffer, 200 μM dntps, 10 U E. coli DNA ligase, 40 U E coli DNA Polymerase I, 2 U of E. coli RNase H up to 150 μl with DEPC-treated water (all reagents were contained in SuperScript Choice System for cDNA Synthesis, Invitrogen). A phenol/chloroform extraction was performed on the ds-cDNA preparation before biotin-labeled cRNA was generated. Synthesis and fragmentation of biotin-labeled cRNA (in vitro transcription). The ENZO BioArrayTM HighYieldTM RNA Transcript Labeling Kit (T7) (Enzo diagnostics, Inc., Farmingdale, NY) was used to produce large amounts of hybridizable biotin-labeled RNA targets by in vitro transcription from the ds-cDNA. The following mix was incubated at 37°C for 5 hours: 1 μg of ds-cDNA, 1X HY reaction buffer, 1X biotin labeled ribonucleotides, 1X dithiothreitol, 1X T7 RNA Polymerase. Biotin-labeled cRNA was run over RNeasy spin columns (Qiagen), quantified, and run on an agarose gel to visualize the size distribution of labeled transcripts. Twenty micrograms of cRNA was incubated with 1X fragmentation buffer for 35 minutes at 94°C. (5X fragmentation buffer: 200 mM Tris-acetate, pH 8.1, 500 mM KOAc, 150 mM MgOAc). After fragmentation, the samples were stored at -20°C until the hybridization was performed. Sample hybridization. Oligonucleotide microarrays (MGU74v2 A, B, and C GeneChip probe arrays; Affymetrix) were hybridized with labeled cRNA derived from spleens from individual mice. For each array,15 μg of fragmented cRNA was mixed with a hybridization cocktail consisting of 1X hybridization buffer (2X hybridization buffer: 100 mM MES, 1 M [Na+], 20 mM EDTA, 0.01% Tween), 0.5 mg/ml acetylated BSA (Invitrogen), 0.1 mg/ml herring sperm DNA (Promega), and water (BioWhittaker) up to 300 μl). Biotin labeled cRNA transcripts of the E. coli and P1 bacteriophage genes, BioB, bioC, bioD, and cre (GeneChip Eukaryotic Hybridization control kit, Affymetrix) were spiked into each hybridization mix at 1.5, 5, 25, and 100 pM to evaluate sample hybridization efficiency for each array. The hybridization cocktail was heated to 99°C and then 45°C for 5 minutes each before it was centrifuged to remove any insoluble material. The array was equilibrated to room temperature, moistened with 1X hybridization buffer, and incubated for 10 minutes at 45°C with rotation. After incubation, the buffer solution was removed from the array. The array was filled with 300 μl of the hybridization cocktail, placed in a rotisserie box in a 45°C oven, and incubated for 16 hours while rotating at 60 rpm. Washing and staining of array. The hybridization cocktail was removed and the GeneChip Fluidics Station 400 (Affymetrix) with Microarray Suite software (Affymetrix) was used to wash and stain the probe arrays with the following protocol: 10 cycles of 2 mixes/cycle with wash buffer A at 25°C, 4 cycles of 15 mixes/cycle with wash buffer B at 50°C, 30 minute incubation with staining solution at 25°C, 10 cycles of 4 mixes/cycle with wash buffer A at 25°C. Wash buffer A -- non-stringent wash buffer (6X sodium chloride sodium phosphate + ethylenediaminetetraacetic acid (SSPE), 0.01% Tween-20). (20X SSPE: 3 M NaCl, 0.2 M NaH2PO4, 0.02 EDTA) (BioWhittaker). Wash buffer B – stringent wash buffer (100mM MES, 0.1 M [Na+], 0.1% Tween 20). Staining solution (1X 2-(N-Morpholino)ethanesulfonic Acid (MES) stain buffer, 2 mg/ml acetylated BSA, 10 μg/ml Streptavidin Phycoerythrin (SAPE), and water up to 600 μl). (12X MES stain buffer: 1.22 M MES, 0.89 M [Na+]). Analysis. After staining, the probe arrays were scanned using the GeneChip 3000 Scanner (Affymetrix) with Microarray Suite software (Affymetrix). Technical and assay variation between arrays was corrected for by multiplying or dividing the overall intensity of each array by a scaling factor so that the overall intensity of each array was equivalent to facilitate comparison analysis. Keywords = BWF1 total spleen Keywords: repeat sample
2005-08-23 | GSE2336 | GEO
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:E. histolytica trophozoites (3x105) harvested in exponential growth phase were transferred to 25 cm² cell culture flasks and grown at 37°C for 24 h. Then, parasites were exposed to irradiation in a 254 nm UV-transilluminator (BioDoc-It Imaging System (UVP)) for 30 min at 4°C (Valdés et al., 2014) and cytoplasmic (CE) and nuclear (NE) extracts were obtained using the NE-PER Kit (Thermo Scientific™) according to manufacturer instructions. Immunoprecipitation (IP) assays were performed using Dynabeads protein A/G (Invitrogen) following manufacturer recommendations. Briefly, Dynabead magnetic beads (25 µl) were coupled with 10 µg of anti-HsCFIm25 polyclonal antibody (GeneTex, GTX115535) and anti-EhCFIm25 polyclonal antibody, previously produced and validated by our group (Pezet-Valdez et al., 2013) for 30 min at room temperature. Then, beads-antibody complex was incubated with NE (100 µg) for 2 h at 37°C followed by three washes with wash buffer (20 mM Tris, pH 7.5; 0.5M NaCl and 0.05% Tween 20). Finally, magnetic bead- antibodies-proteins complex was resuspended in elution buffer (0.1 M glycine, pH 2.0) for 2 minutes at room temperature to dissociate the complex; the tube was placed on the magnet and the supernatant containing eluted antibody and bound proteins was collected.
2023-03-11 | PXD033620 | Pride
Project description:Patients received standardized coartem therapy. Briefly, each pill contains 20 mg of artemether and 120 mg of lumefantrine. The dose and total coarse of tablets is based on the patients body weight. Blood was drawn from patients prior to anti-malarial treatment (day 0) and after treatment (day42 for children and day 28 for adults). Peripheral Blood Mononuclear Cells were isolated from all patients. Briefly, for PBMC isolation, whole blood from was diluted 1:2 in sterile PBS and overlaid on Ficoll Paque-PLUS in 50 mL conical tubes and centrifuged 800xg for 15 minutes at 25°C with no brake. Resulting buffy coats were collected and washed twice in RPMI 1640 medium, and then cells were treated with Red Blood Cell Lysis Buffer for 3 minutes at room temperature. Cells were washed in RPMI and counted on a hemacytometer. Monocytes were purified from PBMC using a miltenyi Pan Monocyte Isolation negative selection kit according to the manufacturer's instructions. For each sample. 50,000 viable cells were pelleted and lysed with cold ATAC-Resuspension Buffer (RSB) containing 0.1% NP40, 0.1% Tween-20, and 0.01% Digitonin and incubated in ice for 3 minutes. The lysaste was washed with 1 ml of cold ATAC-RSB containing 0.1% Tween-20 but NO NP40 or digitonin. Nuclei were pelleted at 500 RCF for 10 min at 4 degrees celcius. The supernatant was discarded and the pellet was resuspended in 50 uL of transposition mixture (25 ul 2x TD buffer, 2.5 ul transposase (100nM final), 16.5 ul PBS,0.5 ul 1% digitonin, 0.5 ul 10% Tween-20, 5 ul H2O). The reaction was incubated for 30 minutes in a thermomixer with 1000 RPM mixing. Zymo DNA Clean and concentrator kit (cat# D4014) was used as a cleanup step. The DNA was amplified at 98 degrees C for 30 seconds, then 13 cycles of: 98 degrees C for 10 seconds, 63 degrees C for 30 seconds, 72 degrees C for 1 minute.The library was evaluated in an Agilent TapeStation system and the DNA concentration evaluated by Qubit. Sequencing was performed on Illumina Nextseq 500 with Buffer cartridge v2: Ref: 15057941, High output reagent cartridge v2: Ref: 15057934, NextSeq accessory Box v2: Ref: 15058251, and High output Flow Cell cartridge v2.5: Ref: 20022408
2022-04-24 | E-MTAB-11643 | biostudies-arrayexpress
Project description:The aim of the project was to purify Xenopus replisome from replicationg chromatin assembled in Xenopus laevis egg extract. To this end recombinant Cdc45-TEV-His10-FLAG5 was expressed in bacteria and purified. 4 ml of Xenopus laevis egg extract was activated into interphase and supplemented with 10 ng/µl of demembranated sperm DNA, 70 nM recombinant Cdc45, 40 µM aphidicolin, 5 mM caffeine and incubated at 23°C for 60 min. Chromatin was isolated in ANIB100 buffer (50 mM HEPES pH 7.6, 100 mM KOAc, 10 mM MgOAc, 2.5 mM Mg-ATP, 0.5 mM spermidine, 0.3 mM spermine, 1 µg/ml of each aprotinin, leupeptin and pepstatin, 25 mM β-glycerophosphate, 0.1 mM Na3VO4 and 10 mM 2-chloroacetamide) as described previously (Gillespie, Gambus et al. 2012). Chromatin pellets re-suspended in ANIB100 containing 20% sucrose. Protein complexes were released from chromatin by digestion with 4 U/µl benzonase nuclease (E1014-25KU, Sigma) and sonicated for 5 min using a sonicator with settings: 30 sec on, 30 sec off, low power (Bioruptor Diagenode UCD-200). Immunoprecipitation was performed using 100 µl of anti-FLAG M2 magnetic beads (Sigma-Aldrich). Before elution the sample was washed four times with 1 ml of ANIB100 20% sucrose, ANIB100 20% sucrose 0.1% Triton X-100, ANIB100 and elution buffer (25 mM HEPES pH 7.5, 100 mM KAc, 5 mM MgAc, 1 mM ATP and 0.02% NP-40), respectively. The sample was eluted adding 250 µM 3xFLAG peptide (Stratech) to 200 µl of elution buffer and a small proportion of it analysed by mass spectrometry.
2023-10-27 | PXD044422 | Pride