library_construction_protocol: A549 cells were harvested from the in vitro culture The CUT&Tag assay was performed using a NovoNGS CUT&Tag 2.0 High-Sensitivity kit (Novoprotein, N259-YH01-01A), anti-FLAG (Proteintech, Cat# 66008-4-Ig, 1:50), and anti-H3K9me3 (Abcam, Cat# ab8898, 1:50) were used.