Loss of Asxl2 leads to myeloid malignancies in mice. [ChIP-Seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE97020 | GEO | 2018/03/08
REPOSITORIES: GEO
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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: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: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
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:In mammals, the peptide hormone vasopressin controls renal water excretion, largely through its actions in the renal collecting duct to regulate the molecular water channel aquaporin-2 (AQP2). There are two modes of regulation: 1) short-term regulation by membrane trafficking; and 2) long-term regulation involving vasopressin-induced changes in the abundance of the aquaporin-2 protein. Defects in the long-term regulation have been implicated in multiple water balance disorders. With the objetive to identify genes that are transcriptionally regulated in response to vasopressin in cultured mouse collecting duct cells (mpkCCD), we carried out both RNA-seq to measure all transcripts (n=9) and ChIP-seq for RNA polymerase II (Polr2a) binding along the genome (n=3). Observations were made both after 24-hr treatment with the vasopressin analog dDAVP and with vehicle. Protocol:Confluent monolayers mpkCCD cells were washed in ice-cold 1X PBS (Ca+2/Mg+2-free) followed by cross-linking in 1.11% formaldehyde in Covaris Fixing Buffer (5.5 ml) for 5min at room temperature with gentle rocking (PN 520075, Covaris, Woburn, Massachusetts). Cross-linking was terminated by the addition of 0.3 ml of 1X Covaris Quenching Buffer with rocking. The buffer solution was aspirated and 1X ice-cold PBS was added to each plate. Cells were scraped into 15ml conical tubes, spun down (200 x g, 5 min), and washed twice with PBS. After the second wash, cell pellets were resuspended in 10 ml of 1X Covaris Lysis Buffer for 10 min at 4o C with rocking. Nuclei were pelleted by spinning at 1,700 x g for 5 min at 4o C. Nuclear pellets was resuspended in the 1X Covaris Wash Buffer and incubated for 10 mins at 4o C with rocking. Samples were spun at 1,700 x g for 5 min at 4o C. Nuclear pellets were washed twice with the Covaris Non-ionic Shearing Buffer and spun at 1,700 x g for 5 min at 4o C. Nuclei were resuspended in Covaris Non-ionic Shearing Buffer (Maximum of 1-3x 10^7cells per ml of buffer). Shearing. Two 20 ul aliquots of the resuspended pellets were removed prior to shearing to be used as subsequent unsheared controls for immunoblotting and agarose gel electrophoresis. The remaining samples were transferred to AFA tubes (TC12 x 12 mm) and volumes adjusted to 1 ml (V)). Samples were sheared using a Covaris S2 SonoLAB Single system for two minutes (Duty cycle: 5%; Intensity: 4; cycle: 200). Total nuclear protein concentration of each sample in mcg/ml (R) was determined with the BCA Protein Assay Kit (Thermo Scientific, Rockford, IL). To test shearing efficiency, a 20 ul aliquot from each tube was removed after shearing to test the efficacy of shearing. The aliquots, including the unsheared sample, were incubated with 100 ul 1X TE buffer, 10 ul 10% SDS, and RNAse A (10 ug/ul, Cell Signaling Technology, Danvers, Massachusetts) for 30 mins at 37o C. 1 ul proteinase K (20 ug/ul) was added and the samples were incubated overnight at 65o C. The DNA was purified using DNA Clean & Concentrator columns (Catalog #: D4013, Zymo Research, Irvine, CA) and ran on an E-gel EX 2% agarose (Invitrogen, Carlsbad, CA). Target fragment sizes for chromatin immunoprecipitation were in the range of 150-700 bp in length with average fragment size of 300 bp. Testing epitope integrity (immunoblotting). Total protein content was determined with the BCA Protein Assay Kit (Thermo Scientific, Rockford, IL). Samples were then diluted with sample buffer (5X Laemmli buffer) at 20% (v/v) of the entire sample volume. Proteins were resolved by SDS-PAGE (4-20% polyacrylamide gels, Criterion, Bio-Rad, Hercules, CA) and transferred electrophoretically onto nitrocellulose membranes as previously described (Hwang, 2010). Membranes were probed with anti-RNA polymerase II (Catalog #: MMS-126R, Covance). The antibody was used at a 1:500 dilution (anti-RNA polymerase II) (in Odyssey blocking buffer containing 0.1% Tween 20) overnight at 4°C. After 1-h incubation with secondary antibody (Li-Cor Biosciences 680 anti-rabbit immunoglobulin G or 800 anti-mouse immunoglobulin G; Lincoln, NE) at 1:5000 dilution, sites of antibody-antigen reaction were detected using an Odyssey infrared imager (Li-Cor). Chromatin immunoprecipitation. 10 ul of sample equivalent to 2% input was removed prior to IP. Chromatin Immunoprecipitation was performed using 30-90 ug of sheared chromatin in 500 uL of 1X Covaris Non-ionic Shearing Buffer with 10 μl anti-RNA polymerase II antibodies. Samples were incubated overnight at 4°C with rotation, followed by addition of ChIP Grade Protein G Magnet Beads (Catalog #: 9006, Cell Signaling Technology) and incubation for 2 h at 4o C with rotation. The beads were washed a total of four times, including three low salt washes followed by one high salt wash for 5 mins/wash at 4o C (SimpleChIP protocol #9003, Cell Signaling Technology). Immunoprecipitated chromatin was eluted from the beads with 150 ul of 1X ChIP Elution Buffer for 30 mins at 65o C in a thermomixer. To reverse crosslinks, 6 ul of 5M NaCl and 2 ul of 20 ug/ul Proteinase K were added to the chromatin followed by incubation at 65o C overnight. DNA was purified according to SimpleChIP protocol #9003, Cell Signaling Technology. q-PCR. To check the success of the chromatin immunoprecipitation, input and ChIP’ed DNA samples were amplified with SYBR Green PCR Master Mix (Applied Biosystems) on a 7900HT Fast Real-Time PCR System. Primer sets corresponding to Hox9a and actin genes were used as positive controls for both histone and RNA polymerase II IP’s. (see Supplementary Table X for primer sequences). Library construction, amplification and sequencing. Loaded fixed volume of total eluate. Library construction was performed on a NuGEN instrument using the protocol and reagents outlined in the Ovation SP Ultralow Library Systems kit. Libraries were then enriched via PCR. After amplification, DNA was measured. A fixed amount of the total measured DNA was used for sequencing in an Illumina Hiseq2000 instrument to obtain single read data. High-throughput sequencing and read mapping. Libraries for Illumina sequencing of the samples were prepared using the the protocol and reagents outlined in the Ovation SP Ultralow Library Systems kit , NuGen Mondrian SP+ (NuGEN, San Carlos, CA) . Samples were sequenced using an Illumina HiSeq2000, obtaining 1- by 50-bp reads.
2016-07-01 | GSE79573 | GEO
Project description:CTCF is a highly conserved and ubiquitously expressed protein involved in several fundamental processes such as fine-tuning gene expression, imprinting, X-chromosome inactivation and 3D chromatin organisation. To understand the impact of differences in the concentration of CTCF abundance on these processes, we exploit a CTCF hemizygous mouse model with a stable reduction in the concentration of this protein. We derived twelve independent primary lines of mouse embryonic fibroblasts (MEFs) from six wildtype and six CTCF-hemizygous mouse E13.5 embryos. MEFs were fixed in DMEM containing 1% fresh formaldehyde and incubated at room temperature for 10 min, quenched with 250mM glycine for 10 min, and washed twice with ice cold PBS, before being flash-frozen at -80°C. Cross-linked cells were lysed and sonicated on a Bioruptor Plus (Diagenode) sonicator to fragment chromatin to an average length of 300bp. 10 ug of the following antibodies were used for immunoprecipitation: CTCF (rabbit polyclonal, Merk Millipore 07-729, lot 2517762); H3K4me3 (mouse monoclonal IgG clone CMA304, Merck Millipore 05-1339, lot 2603814); H3K27ac (rabbit polyclonal IgG, Abcam 4729, lot GR244014-1). Immunoprecipitated DNA or 50 ng of input DNA was used for library preparation using the ThruPLEX DNA-Seq library preparation protocol (Rubicon Genomics, UK). Library fragment size was determined using a 2100 Bioanalyzer (Agilent). Libraries were quantified by qPCR (Kapa Biosystems). Pooled libraries were sequenced on a HiSeq4000 (Illumina) according to manufacturer’s instructions using single-end 50 bp reads. On the same MEF lines we have performed RNAseq and HiC (see related accession numbers).
2018-07-29 | E-MTAB-6261 | biostudies-arrayexpress
Project description:The aryl hydrocarbon receptor (AHR) agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alters differentiation of B cells and suppresses antibody production. The objectives of this study was to use a combination of whole genome, microarray-based chromatin immunoprecipitation (ChIP-on-chip) and time course gene expression microarray analysis on the mouse B-cell line CH12.LX following exposure to lipopolysaccharide (LPS) or LPS and TCDD to identify the primary and downstream transcriptional elements of B-cell differentiation that are altered by the AHR. CH12.LX cells (1X10^5 cells/ml, 25ml in P150s) were treated with either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)(10nM) or vehicle (0.01% DMSO) for 1 hr and cells were fixed with 1% formaldehyde for 15 min and quenched with 0.125 M glycine. Chromatin was isolated by adding lysis buffer followed by disruption with a Dounce homogenizer. Lysates were sonicated and the DNA sheared to an average length of 300-500 bp. Genomic DNA was prepared by treating aliquots of chromatin with RNase, proteinase K and heat for de-crosslinking, followed by ethanol precipitation. Pellets were resuspended and the resulting DNA was quantified on a Nanodrop ND-1000 spectrophotometer. Extrapolation to the original chromatin volume allowed quantitation of the total chromatin yield. An aliquot of chromatin (30 ug) was precleared with protein - agarose beads. Factor-bound DNA sequences were isolated using antibodies against AhR (Biomol, Plymouth Meeting, PA, Catalog #: SA210-0100). After incubation at 4°C overnight, protein-agarose beads were used to isolate the immune complexes. Complexes were washed, eluted from the beads with SDS buffer, and subjected to RNase and proteinase K treatment. Crosslinks were reversed by incubation overnight at 65°C, and ChIP DNA was purified by phenol-chloroform extraction and ethanol precipitation. Following purification ChIP DNA was labeled, fragmented and hybridized to Affymetrix GeneChip Mouse Tiling 2.0 Array Sets, hybridized arrays were then washed and scanned using a GeneChip Fluidics Station 450 and a GeneChip 3000 scanner. The ChIP studies were performed in triplicate (n = 3) with the cells for each replicate treated and harvested on separate days.
2010-08-31 | E-GEOD-23708 | biostudies-arrayexpress
Project description:Examination of EBf1 binding by ChIP-seq in differentiated human adipose stromal cell (hASC) pre-adipocyte Pre-Adipocytes differentiated in-vitro were fixed in 1% formaldehyde for 15 min at room temperature and quenched for 5 min by adding glycine to a final concentration of 0.125 M. ChIP assays were then performed with custom-made EBF1 antibody or rabbit IgG . ChIP-sequencing libraries were prepared using NEBnext chip-seq library Prep master mix set from 5 ng of anti-EBF1 and anti-IgG ChIP DNA, respectively. Sequence data were generated with Illumina HiSeq 2000 single-read sequencing and aligned against the human genome (hg19, NCBI).
2014-05-22 | E-GEOD-54889 | biostudies-arrayexpress
Project description:CD4+ T cells were cultured in iTreg cell polarizing condition for 72h. ChIP was performed as previously described (Tripathi et al., Cell Reprot 2017) with slight modifications. The cells were subjected to sonication using Bioruptor® Pico sonication device (Diagenode) to attain 100–500 bp chromatin fragments size. A total of 250 ug of sonicated chromatin fragments were incubated with 10ug of HIC-1 antibody (Santa Cruz, sc-271499) and incubated for crosslinking with magnetic beads (no. 11201D, Dynabeads® M-280 Sheep Anti-Mouse IgG, Dynal Biotech, Invitrogen). The crosslink samples were reversed at 65oC overnight and precipitated DNA was treated with Rnase A and Proteinase K and purified with QIAquick PCR purifica-tion kit (QIAGEN). The DNA libraries were prepared as per the guidelines from Illumina by Fasteris Life Sciences (Plan-les-Ouates, Switzerland). Input DNA was sequenced and used as a control. DNA libraries were sequenced on Illumina HiSeq2500 producing from 25 to 35 million reads per sample. The 50 nucleotide reads were aligned to hg19 build of human reference genome using bowtie2 (ver-sion 2.2.9). Uniquely mapped reads were retained (~20-25 million reads per sample) for further analysis. HIC-1 binding sites relative to input DNA were identified using MACS2 (version 2.1.1.20160309) with the default parameter settings. De novo motifs from HIC-1 ChIP-seq peaks were discovered using Homer (version 4.8). The binding sites were annotated in terms of genomic annotations using the “annotatePeaks.pl” script supplied as part of Homer. HIC-1 motif locations in ChIP-Seq peaks were scanned using Homer with default parameters (with the addition of –local argument).
2018-02-21 | GSE99889 | GEO
Project description:In mammals, the peptide hormone vasopressin controls renal water excretion, largely through its actions in the renal collecting duct to regulate the molecular water channel aquaporin-2 (AQP2). There are two modes of regulation: 1) short-term regulation by membrane trafficking; and 2) long-term regulation involving vasopressin-induced changes in the abundance of the aquaporin-2 protein. Defects in the long-term regulation have been implicated in multiple water balance disorders. With the objetive to identify genes that are transcriptionally regulated in response to vasopressin in cultured mouse collecting duct cells (mpkCCD), we carried out both RNA-seq to measure all transcripts (n=9) and ChIP-seq for RNA polymerase II (Polr2a) binding along the genome (n=3). Observations were made both after 24-hr treatment with the vasopressin analog dDAVP and with vehicle. Protocol:Confluent monolayers mpkCCD cells were washed in ice-cold 1X PBS (Ca+2/Mg+2-free) followed by cross-linking in 1.11% formaldehyde in Covaris Fixing Buffer (5.5 ml) for 5min at room temperature with gentle rocking (PN 520075, Covaris, Woburn, Massachusetts). Cross-linking was terminated by the addition of 0.3 ml of 1X Covaris Quenching Buffer with rocking. The buffer solution was aspirated and 1X ice-cold PBS was added to each plate. Cells were scraped into 15ml conical tubes, spun down (200 x g, 5 min), and washed twice with PBS. After the second wash, cell pellets were resuspended in 10 ml of 1X Covaris Lysis Buffer for 10 min at 4o C with rocking. Nuclei were pelleted by spinning at 1,700 x g for 5 min at 4o C. Nuclear pellets was resuspended in the 1X Covaris Wash Buffer and incubated for 10 mins at 4o C with rocking. Samples were spun at 1,700 x g for 5 min at 4o C. Nuclear pellets were washed twice with the Covaris Non-ionic Shearing Buffer and spun at 1,700 x g for 5 min at 4o C. Nuclei were resuspended in Covaris Non-ionic Shearing Buffer (Maximum of 1-3x 10^7cells per ml of buffer). Shearing. Two 20 ul aliquots of the resuspended pellets were removed prior to shearing to be used as subsequent unsheared controls for immunoblotting and agarose gel electrophoresis. The remaining samples were transferred to AFA tubes (TC12 x 12 mm) and volumes adjusted to 1 ml (V)). Samples were sheared using a Covaris S2 SonoLAB Single system for two minutes (Duty cycle: 5%; Intensity: 4; cycle: 200). Total nuclear protein concentration of each sample in mcg/ml (R) was determined with the BCA Protein Assay Kit (Thermo Scientific, Rockford, IL). To test shearing efficiency, a 20 ul aliquot from each tube was removed after shearing to test the efficacy of shearing. The aliquots, including the unsheared sample, were incubated with 100 ul 1X TE buffer, 10 ul 10% SDS, and RNAse A (10 ug/ul, Cell Signaling Technology, Danvers, Massachusetts) for 30 mins at 37o C. 1 ul proteinase K (20 ug/ul) was added and the samples were incubated overnight at 65o C. The DNA was purified using DNA Clean & Concentrator columns (Catalog #: D4013, Zymo Research, Irvine, CA) and ran on an E-gel EX 2% agarose (Invitrogen, Carlsbad, CA). Target fragment sizes for chromatin immunoprecipitation were in the range of 150-700 bp in length with average fragment size of 300 bp. Testing epitope integrity (immunoblotting). Total protein content was determined with the BCA Protein Assay Kit (Thermo Scientific, Rockford, IL). Samples were then diluted with sample buffer (5X Laemmli buffer) at 20% (v/v) of the entire sample volume. Proteins were resolved by SDS-PAGE (4-20% polyacrylamide gels, Criterion, Bio-Rad, Hercules, CA) and transferred electrophoretically onto nitrocellulose membranes as previously described (Hwang, 2010). Membranes were probed with anti-RNA polymerase II (Catalog #: MMS-126R, Covance). The antibody was used at a 1:500 dilution (anti-RNA polymerase II) (in Odyssey blocking buffer containing 0.1% Tween 20) overnight at 4°C. After 1-h incubation with secondary antibody (Li-Cor Biosciences 680 anti-rabbit immunoglobulin G or 800 anti-mouse immunoglobulin G; Lincoln, NE) at 1:5000 dilution, sites of antibody-antigen reaction were detected using an Odyssey infrared imager (Li-Cor). Chromatin immunoprecipitation. 10 ul of sample equivalent to 2% input was removed prior to IP. Chromatin Immunoprecipitation was performed using 30-90 ug of sheared chromatin in 500 uL of 1X Covaris Non-ionic Shearing Buffer with 10 μl anti-RNA polymerase II antibodies. Samples were incubated overnight at 4°C with rotation, followed by addition of ChIP Grade Protein G Magnet Beads (Catalog #: 9006, Cell Signaling Technology) and incubation for 2 h at 4o C with rotation. The beads were washed a total of four times, including three low salt washes followed by one high salt wash for 5 mins/wash at 4o C (SimpleChIP protocol #9003, Cell Signaling Technology). Immunoprecipitated chromatin was eluted from the beads with 150 ul of 1X ChIP Elution Buffer for 30 mins at 65o C in a thermomixer. To reverse crosslinks, 6 ul of 5M NaCl and 2 ul of 20 ug/ul Proteinase K were added to the chromatin followed by incubation at 65o C overnight. DNA was purified according to SimpleChIP protocol #9003, Cell Signaling Technology. q-PCR. To check the success of the chromatin immunoprecipitation, input and ChIPâ??ed DNA samples were amplified with SYBR Green PCR Master Mix (Applied Biosystems) on a 7900HT Fast Real-Time PCR System. Primer sets corresponding to Hox9a and actin genes were used as positive controls for both histone and RNA polymerase II IPâ??s. (see Supplementary Table X for primer sequences). Library construction, amplification and sequencing. Loaded fixed volume of total eluate. Library construction was performed on a NuGEN instrument using the protocol and reagents outlined in the Ovation SP Ultralow Library Systems kit. Libraries were then enriched via PCR. After amplification, DNA was measured. A fixed amount of the total measured DNA was used for sequencing in an Illumina Hiseq2000 instrument to obtain single read data. High-throughput sequencing and read mapping. Libraries for Illumina sequencing of the samples were prepared using the the protocol and reagents outlined in the Ovation SP Ultralow Library Systems kit , NuGen Mondrian SP+ (NuGEN, San Carlos, CA) . Samples were sequenced using an Illumina HiSeq2000, obtaining 1- by 50-bp reads. We combine RNA-seq and ChIP-seq to identify genes whose mRNA abundances change in tandem with changes in RNA polymerase II binding, as a mean to identify genes that are transcriptionally regulated in response to vasopressin. In addition, the pattern of RNA polymerase II binding along the gene provides important information about regulatory mechanisms. We identify two populations of genes regulated by vasopressin in mpkCCD cells, viz. 1) those with increases in transcript abundance and increases in RNA polymerase II binding throughout the gene body and; 2) genes that show increases in RNA polymerase II binding in the promotor proximal region but do not produce increases in transcript level. The former group is restricted to 35 genes and includes Aqp2. The latter group is made up of the majority of expressed genes and is presumably due to a widespread increase in transcriptional initiation without proportionate release of pausing.
2016-07-01 | E-GEOD-79573 | biostudies-arrayexpress