library_construction_protocol: 1 mL of nuclear lysis buffer (10 mM Tris-HCl, pH=7.4; 10 mM NaCl; 3 mM MgCl₂; 0.1% NP40; 0.1% Tween 20; 0.01% Digoxigenin) was added to resuspend the tissues. The samples were then homogenized using a Dounce homogenizer with 10 strokes each using pestle A and pestle B. The nuclear suspension was filtered through a 40 µm Flowmi Cell strainer, followed by centrifugation at 800 × g for 5 min at 4 °C. The resulting pellet was resuspended in wash buffer. Nuclear integrity was assessed by methylene blue staining, and nuclei concentration was determined using a hemocytometer (BS-QT-1103, Biosharp, Anhui, China) under a Nikon Eclipse Ni DIC microscope (model YTV55). 50,000 nuclei were resuspended in 1 mL of cold wash buffer and centrifuged at 500 × g for 5 min at 4 ℃. The pellet was resuspended in 40 μL of tagmentation buffer (0.3× PBS, 0.1% Tween-20, 0.01% digitonin, 1× TD buffer, 1× pA-Tn5 transposome mix) and incubated at 37 °C for 30 min. The reaction was stopped by adding 10 μL of stop buffer, followed by incubation at 55 °C for 5 min. DNA was then purified using 100 μL of Tagment DNA extract beads and eluted in 37 μL of elution buffer. The purified DNA was amplified with 5× AmpliMix using the N5 and N7 index primers. The purified DNA libraries were size selected using NovoNGS® DNA Clean Beads (N240, Novoprotein, Shanghai, China) and sequenced on the NovaSeq X platform.