title: GSM6124013: GM12878_FC4; Homo sapiens; OTHER
library_construction_protocol: 15 million GM12878 or K562 cells were spun down and resuspended in 10 ml fresh medium. Cells were fixed with 1% formaldehyde and incubating for 10 minutes at room temperature (RT). After quenching, cell were lysed and cell nuclei were collected, then chromatin was digested with DpnII restriction enzyme and ligated with T4 DNA ligase, and recrosslinking reversal was performed with Proteinase K or Pronase.  Finally DNA was purified using Phenol-Chloroform Isoamyl alcohol method. A total amount of 3-4ug purified DNA per sample was used as input material for the ONT library preparations. After the sample was qualified, size select of ligation DNA > 3kb were performed using the PippinHT system(Sage Science, USA). Next, the ends of DNA were repaired, and A-ligation reaction were conducted with NEBNext Ultra II End Repair/dA-tailing Kit(Cat# E7546). The adapter in the SQK-LSK109(Oxford Nanopore Technologies, UK) was used for further ligation reaction and DNA library was measured by Qubit 4.0 Fluorometer(Invitrogen, USA).