GSM6297315
Cell nuclei were extracted and sonicated. G4 containing DNA  was isolated with SG4 antibody.  For SG4 ChIP libraries, DNA was tagmented and the library was prepared using Nextera library preparation kit (20034197) by following the manufacturer instruction. The library was amplified using Nextera index primers (Illumina, FC-121-1030). Nanobody purification protocol: BL21 (DE3) E. coli chemically competent cells were transformed with pHEN2 plasmid carrying SG4 wild type sequence. Single colonies were inoculated in Terrific Broth medium the addition of 1% glucose and 100 μg/ml ampicillin. After overnight incubation, the starting culture were transferred into Terrific Broth medium containing 0.1% glucose and 100 μg/ml ampicillin, incubated at 37 °C until bacterial OD600 reached a value in the range of 0.6-0.8. After that, bacteria were induced with 0.5 mM IPTG for ~16 h at 28 °C. Bacterial lysed fraction containing the nanobody was loaded on Proteus 1-step batch Midi Spin columns (Generon) with Nickel resin (Sigma), and incubated at 4 °C for 1 hour, then the nanobo Pulled-down DNA was tagmented using Illumina Tagment DNA TDE1 Enzyme and Buffer Kit following manifacturers' protocol. The libraries were prepared using Nextera XT Index Kit, amplified wuth NEB Next High Fidelity 2x PCR Master Mix, and cleaned up using Qiagen MinElute Reaction Cleanup Kit.