library_construction_protocol: The HeLa cells were suspended in the washing solution containing 15 mM Tris-HCl (pH 8.0), 15 mM NaCl, 60 mM KCl, 300 mM sucrose, and a proteinase inhibitor (Roche). The detergent buffer containing 15 mM Tris-HCl (pH 8.0), 15 mM NaCl, 60 mM KCl, 300 mM sucrose, proteinase inhibitor (Roche), and 1% NP-40 was then added to the cell suspension, and the mixture was rotated at 4 ºC for 10 minutes. The HeLa nuclei were collected by centrifugation and were resuspended in the washing solution. A large amount of MNase (3 units/µL) and CaCl2 (2 mM) were added to the HeLa nuclei suspension. The MNase treatment was performed under 37 ºC for 30 minutes, and was terminated by EDTA (pH 8.0) addition. The MNase fragments were precipitated by ethanol, and were electrophoresed by 4% agarose gel. Libraries were prepared using ThruPLEX DNA-Seq Kit (Clontech, #R400674).