title: GSM7210830: DHX9 knockdown, POLR2A-ChIP, rep1; Homo sapiens; ChIP-Seq
library_name: GSM7210830
library_construction_protocol: the cells were crosslinked with 1% formaldehyde at room temperature for 10 min with gentle shaking, and quenched with 125 mM glycine for 10 min. After washing with ice-cold PBS buffer for three times, the cells were resuspended in cell lysis buffer (10 mM Tris-HCl, pH 8.0, 10 mM NaCl, 0.5% NP-40, protease inhibitors) at 4°C on a rotator for 20 min. After centrifugation at 3000 g for 3 min, the pellets were resuspended in RIPA buffer (50 mM Tris-HCl, pH 8.0, 150 mM NaCl, 2 mM EDTA, 1% NP-40, 0.5% sodium deoxycholate, 0.1% SDS, protease inhibitors) and rotated at 4°C for 20 min, followed by a brief sonication on a Qsonica Sonicator q125 (42% amplitude, 10s on/10s off, 80 s). After incubation for another 20 min, cell lysate was sonicated on a Covaris S220 Sonicator for 6 min with a peak incident power of 140 W, a duty cycle of 10.1% and 200 cycles per burst at 4°C. After centrifugation at 4°C for 10 min, 50 µL of supernatant was saved as “Input” sample, and the rest of supernatant was subjected to IP experiment. The DNA-sequencing library was prepared using NEBNext Ultra DNA Library Prep Kit for Illumina (NEB) following the manufacturer's instructions.