Cells were fixed with 1% formaldehyde (Sigma) for 10’ at 37°C. Fixation was quenched by addition of glycine (Sigma) at a final concentration of 125 mM. Twenty million fixed cells were washed with PBS and resuspended in 2 ml of RIPA buffer (10 mM Tris [pH 7.6], 1 mM EDTA, 0.1% SDS, 0.1% sodium deoxycholate, 1% Triton X-100, 1× Complete Mini EDTA free proteinase inhibitor (Roche)) or stored at −80°C until further processing. Sonication was performed using the Covaris S2 sonicator at duty cycle 20%, intensity 5, cycle/burst 200 for 30 min or using the Branson sonifier at amplitude 35%, 12 cycles of 20” sonication and 30” of pause. Ten microgram of respective antibody was incubated with 40 μl of Dynabeads Protein A (or G) for 15 min at room temperature. Antibody-bound beads were added to 1 ml of sonicated chromatin, incubated at 4°C overnight, and washed twice with RIPA buffer, twice with RIPA buffer containing 0.3M NaCl, twice with LiCl buffer (0.25 M LiCl, 0.5% Igepal-630, 0.5% sodium deoxycholate), once with TE (pH 8.0) plus 0.2% Triton X-100, and once with TE (pH 8.0). Crosslinking was reversed by incubating the beads at 65°C for 4 hr in the presence of 0.3% SDS and 1 mg/ml Proteinase K. ChIP DNA was purified using ChIP DNA Clean & Concentrator kit (Zymo). The library was prepared using the Ovation SP Ultralow library system (Nugen). 75 cycles of sequencing data were acquired on and Nextseq550 (Illumina). Antibodies for ChiP-seq were: anti-RAD21 (ab992, Abcam), anti-CTCF (07-729, Millipore), Topo IIβ Antibody (H-286) (sc13059, SantaCruz) and Topoisomerase II alpha antibody (EP1102Y) (ab52934, Abcam) libraries were prepared and sequenced following standard Illumina protocols