GSM2341277: BRG1fl_ATAC_UNT_rep1 (ATAC-Seq); Mus musculus; OTHER
Chromatin accessibility was assayed using an adaptation of the assay for transposase accessible-chromatin (ATAC)-seq (Buenrostro et al., 2013). Briefly, 5 × 106 cells were harvested, washed with PBS and nuclei were isolated using 1 mL HS Lysis buffer (50 mM KCl, 10 mM MgSO4.7H20, 5 mM HEPES, 0.05 % NP40 (IGEPAL CA630)), 1 mM PMSF, 3 mM DTT)  for 1 min at room temperature. Nuclei were centrifuged at 1,000 × g for 5 min at 4°C, followed by a total of three washes with ice-cold RSB buffer (10mM NaCl, 10mM Tris (pH 7.4), 3mM MgCl2), to remove as much of contaminating cytoplasmic and mitochondrial material as possible. Nuclei were then counted, and 5×104 nuclei were resuspended in Tn5 reaction buffer (10mM TAPS, 5mM MgCl2, 10% dimethylformamide) and 2 µl of Tn5 transposase (25µM) made in house according to the previously described protocol (Picelli et al., 2014). Nuclei were then incubated for 30 min at 37°C, before isolation and purification of tagmented DNA using QiaQuick MinElute columns (Qiagen). To control for sequence bias of the Tn5 transposase, an ATAC “input” sample was generated, by tagmenting genomic DNA from ESCs with Tn5 for 30 min at 55°C. ATAC-seq libraries were prepared by PCR amplification using custom made Illumina barcodes previously described (Buenrostro et al., 2013) and the NEBNext® High-Fidelity 2X PCR Master Mix with 8-10 cycles. Libraries were purified with two rounds of AMPure XP bead cleanup (1.5X beads:sample), followed by quantification by qPCR using SensiMix SYBR (Bioline) and KAPA Library Quantification DNA standards (KAPA Biosystems). ATAC-seq libraries were sequenced on Illumina NextSeq500 using 80bp paired-end reads in biological triplicate.
GEO Accession
GSM2341277