library_construction_protocol: Human endometrial stromal cells were digested with 0.25% Trypsin for 5 min at 37 ℃ to get single cell suspension, then washed and incubated with activated concanavalin A beads for 10 min at room temperature. Cells were then resuspended in antibody buffer containing 0.01% digitonin, 1ul of each antibody was added to individual cell aliquots, and tubes were rotated at 4°C overnight. The following day, targeted chromatin digestion and release were performed with 2.5 ul of Cutana pA/G-MNase and 1 ul of 100 mM CaCl2. Genomic DNA with 0.05ng of Spike-in DNA together was purified with phenol-chloroform and ethanol precipitated. Sequencing libraries were prepared using NEBNext Ultra II DNA Library Prep Kit following manufacture's protocol.