title: ATAC-seq of mus musculus
design: ATAC-seq was performed using the TruePrepTM DNA Library Prep Kit V2 according to the manufacturer's instructions. 20 ICMs were lysed in 10 L of lysis buffer containing 10 mM Tris-HCl (pH 7.4), 10 mM NaCl, 3 mM MgCl2, and 0.5% NP-40 on ice for 10 minutes, followed by centrifugation at 500 g for 3 minutes, with the supernatant removed to obtain cell nuclei. The samples were then incubated with Tn5 transposase and fragmentation buffer at 37C for 1 hour (Vazyme Biotech). Subsequently, 5 l of 5 x TS buffer was added and incubated at room temperature for 5 minutes to stop the reaction. Next, to amplify the library, the following PCR reaction was performed: 72C for 3 minutes; 98C for 30 seconds; 20 cycles of 98C for 15 seconds, 60C for 30 seconds, and 72C for 3 minutes; and finally, 72C for 5 minutes. After the PCR reaction, the library was purified using 1.5x volume of DNA Clean Beads (N411, Vazyme Biotech). The libraries were sequenced on the DNBSEQ-T7 platform.