title: GSM8371947: shCtrl, G4-ChIP, rep2; Homo sapiens; ChIP-Seq
library_construction_protocol: G4-ChIP was conducted by following previously described procedures with slight modifications, using the custom-purified BG4 antibody7. Briefly, the chromatin samples were sonicated and diluted in a blocking buffer containing 25 mM HEPES (pH 7.5), 10.5 mM NaCl, 110 mM KCl, 1 mM MgCl2, and 1% BSA, and treated with RNase A. Subsequently, the chromatin samples were incubated with 500 ng of the BG4 antibody under rotation at 1400 rpm for 1.5 hr at 16°C. Pre-blocked Anti-Flag M2 magnetic beads (Sigma, M8823) were added to the mixture, which was then incubated under the same conditions for 1 hr. After washing the beads with ice-cold washing buffer (10 mM Tris, pH 7.4, 100 mM KCl, 0.1% Tween 20) for 6 cycles, the DNA was eluted with TE buffer containing proteinase K while rotating at 1400 rpm for 6 hr at 65 °C. The eluted DNA was purified using the DNA Clean and Concentrator-5 kit (Zymo). ChIP-seq library was prepared using the NEBNext® Ultra™ II DNA Library Prep Kit (NEB) following the manufacturer's instruction. The purified DNA libraries were subsequently quantified using an Agilent 2100 Bioanalyzer and multiplexed for sequencing at Genomics Research and Technology Hub (Nova-seq 6000, GRT Hub, UC Irvine) with 100-bp paired-end sequencing.