anti-NEDD4 (D17, sc-14482, Santa Cruz Biotechnology)
Sequenced DNA Library
library_strategy
ChIP-Seq
library_source
GENOMIC
library_selection
ChIP
library_construction_protocol
ChIP was performed as previously described. Briefly, cells were cross-linked with 1% formaldehyde at room temperature for 10 min. For KDM2A ChIP, cells were double cross-linked with 2mM DSG (ProteoChem Cat# C1104) for 45 min and then for another 15 min with 1% formaldehyde (Sigma, F8775). In both situations, the cross-linking was quenched with 0.125M glycine for 5 min. Chromatin was fragmented using a Bioruptor (Diagenode) for 30 min at high power, with an interval of 30 s between pulses to get 200-500bp fragments and precleared using 20 µl Protein G Dynabeads (Life Technologies, Cat# 10009D). Subsequently, the soluble chromatin was incubated with 2-5 µg antibodies at 4°C overnight. Immunoprecipitated complexes were collected using 20 µl Protein G Dynabeads per reaction. We performed biotin ChIP or biotin ChIP-seq experiments for BLRP-tagged KDM2A and ERa, and ERa P-box mutation stable cell lines following an earlier protocol. Briefly, cross-linked protein-DNA complexes were pulled down by M-280 Streptavidin Magnetic beads (Life Technologies, Cat# 11205D) and the washing was performed under much more stringent conditions that included 2 washes with 1% SDS in TE (20 min each) and two washes with 1% Triton X-100 in TE. The washed streptavidin beads were then subjected to AcTEV protease (Life Technologies, Cat# 12575-015) digestion twice for tagged protein and DNA complex elution before de-crosslinking at 65°C overnight. For all ChIPs, after de-crosslinking overnight at 65°C, final ChIP DNA was extracted and purified using QIAquick spin columns (QIAGEN). The ChIP-seq libraries were constructed following Illumina's ChIP-seq Sample prep kit. The library was amplified by 14 cycles of PCR. ChIP was performed as previously described. Briefly, cells were cross-linked with 1% formaldehyde at room temperature for 10 min. For KDM2A ChIP, cells were double cross-linked with 2mM DSG (ProteoChem Cat# C1104) for 45 min and then for another 15 min with 1% formaldehyde (Sigma, F8775). In both situations, the cross-linking was quenched with 0.125M glycine for 5 min. Chromatin was fragmented using a Bioruptor (Diagenode) for 30 min at high power, with an interval of 30 s between pulses to get 200-500bp fragments and precleared using 20 µl Protein G Dynabeads (Life Technologies, Cat# 10009D). Subsequently, the soluble chromatin was incubated with 2-5 µg antibodies at 4°C overnight. Immunoprecipitated complexes were collected using 20 µl Protein G Dynabeads per reaction. We performed biotin ChIP or biotin ChIP-seq experiments for BLRP-tagged KDM2A and ERa, and ERa P-box mutation stable cell lines following an earlier protocol. Briefly, cross-linked protein-DNA complexes were pulled down by M-280 Streptavidin Magnetic beads (Life Technologies, Cat# 11205D) and the washing was performed under much more stringent conditions that included 2 washes with 1% SDS in TE (20 min each) and two washes with 1% Triton X-100 in TE. The washed streptavidin beads were then subjected to AcTEV protease (Life Technologies, Cat# 12575-015) digestion twice for tagged protein and DNA complex elution before de-crosslinking at 65°C overnight. For all ChIPs, after de-crosslinking overnight at 65°C, final ChIP DNA was extracted and purified using QIAquick spin columns (QIAGEN). The ChIP-seq libraries were constructed following Illumina's ChIP-seq Sample prep kit. The library was amplified by 14 cycles of PCR. GRO-seq experiments were performed as previously reported with a few modifications. Briefly, ~10 millions of MCF7 cells treated with E2 for 1 hr were washed 3 times with cold PBS and then sequentially swelled in swelling buffer (10mM Tris-HCl pH7.5, 2mM MgCl2, 3mM CaCl2) for 10 min on ice, harvested, and lysed in lysis buffer (swelling buffer plus 0.5% NP-40, 20 units of SUPERase-In, and 10% glycerol). The resultant nuclei were washed two more times with 10ml lysis buffer and finally resuspended in 100 µl of freezing buffer (50mM Tris-HCl pH8.3, 40% glycerol, 5mM MgCl2, 0.1mM EDTA). For the run-on assay, resuspended nuclei were mixed with an equal volume of reaction buffer (10mM Tris-HCl pH 8.0, 5mM MgCl2, 1mM DTT, 300mM KCl, 20 units of SUPERase-In, 1% sarkosyl, 100 µM A/GTP, 100 µM biotin-11-C/UTP (Perkin-Elmer) and incubated for 5 min at 30°C. The resultant nuclear-run-on RNA (NRO-RNA) was then extracted with TRIzol® LS reagent (Life Technologies, Cat# 10296-028) following manufacturer's instructions. NRO-RNA was fragmented to ~200-500nt by alkaline base hydrolysis on ice for 30 min and and neutralized by adding 1× volume of 1 M Tris-HCl pH 6.8, Excessive salt and residual NTPs were removed by using P-30 column (Bio-Rad, Cat# 732-6250), followed by treatment with DNase I (Promega Cat# M6101) and antarctic phosphatase (NEB Cat# M0289L). Fragmented nascent RNA was bound to 10 µl of MyOne Streptavidin C1 dynabeads (Invitrogen, Cat# 65001) following the manufacturer's instructions. The beads were washed twice in high salt (2 M NaCl, 50 mM Tris-HCl pH 7.5, 0.5% Triton X-100, 0.5 mM EDTA), once in medium salt (1M NaCl, 5 mM Tris-HCl pH 7.5, 0.1% Triton X-100, 0.5 mM EDTA), and once in low salt (5 mM Tris-HCl pH 7.5, 0.1% Triton X-100). Bound RNA was extracted from the bead using Trizol (Invitrogen, Cat# 15596-018) in two consecutive extractions, and the RNA fractions were pooled, followed by ethanol precipitation. The RNA fragments were then subjected to poly-A tailing reaction by poly-A polymerase (NEB, Cat# M0276L) for 30 min at 37°C. Subsequently, reverse transcription was performed using oNTI223 primer and superscript III RT kit (Life Technologies, Cat# 18080-044). The cDNA products were separated on a 10% polyacrylamide TBE-urea gel and only those fragments migrating between 100-400bp were excised and recovered by gel extraction. Next, the first-strand cDNA was circularized by CircLigase (Epicenter, Cat# CL4115K) and relinearized by APE1 (NEB, Cat# M0282L). Finally, cDNA template was amplified by PCR using the Phusion High-Fidelity enzyme (NEB, Cat# M0530L) according to the manufacturer's instructions. The oligonucleotide primers oNTI200 and oNTI201 were used to generate DNA library for deep sequencing and the primer sequences were described in previous paper.