library_construction_protocol: To isolate nuclei, 50.000 cells were resuspended in 50ul cold lysis buffer (10mM Tris-HCl pH7.4, 10mM NaCl, 3mM MgCl2, 0.1% Igepal C-630), the mixture was pipetted up and down 16 times and immediately centrifuged at 500g for 10min at +4C. The pellet was used for tagmentation reaction, which was performed with 2.5ul TDE1 in 50ul total volume (FC-121-1031, Nextera DNA Library Prep Kit, Illumina). The samples were then further amplified (Nextera kit FC-121-1030) and barcoded with the corresponding indices (FC-121-1011). The final libraries were then cleaned up with 1.2x vol AMPure XP beads.