Chromatin fraction obtained from Eph4 cells or FACS-sorted mammary epithelial cells were incubated with antibodies that recognize mouse histone H3K27ac or mouse c-Myc protein. 1/10 of chromatin fraction was saved as Input. Chromatin-antibody were isolated with magnetic beads. DNA purified with ChIP DNA kit (Zymo) according the manufacturer's instruction ChIP library samples were amplified and barcoded using Clontech DNA Smart Chipseq kit and Clontech Indexing set in accordance with the manufacturer’s instructions, then pooled for sequencing.