Nuclei obtained from Eph4 cells or FACS-sorted mammary epithelial cells were incubated with reagents from Illumina Nextera kit (Illumina), following DNA purification with purified with DNA Clean-up & Concentration kit (Zymo) according the manufacturer's instruction Nextera treated, purified DNA was amplified and barcoded using previously described protocol (Buenrostro e at, 2013), then pooled for sequencing.