Cells were collected by FACS purification into cold PBS, and centrifuged 500 xg for 15 min. Cell pellet were resuspended with 50 ul transposition buffer consisting of 10mM Tris-HCL pH8.0, 5 mM MgCl2, 10% DMF, 0.2% NP40, and home-made transposase Tn5. Transposition was performed at 37 degree for 20 min. DNA was collected immediately after transposition using Qiagen Mini-elute kit. Library was prepared using primers from Illumina Nextera DNA Library Preparation Kit.