ATAC-seq libraries were prepared by using the ATAC-Seq Kit (Active motif; 53150) following manufacturer's instructions. Briefly, 1x105  live sorted cells were pelleted by centrifugation at 500 g for 5 minutes at 4C. The cell pellet was resuspended thoroughly in 100 ul ice-cold ATAC Lysis Buffer. After spinning down at 500 g for 10 minutes at 4C, the nuclear pellet was tagmented in 50 ul of Tagmentation Master Mix at 37C for 30 minutes. For library preparation,  the tagmented DNA was amplified with indexed Primer by PCR reaction following column purification. Prepared libraries were sequenced on the NovaSeq platform (Illumina).