Chromatin immunoprecipitation (ChIP)

ChIP was performed using a SimpleChIP^® Enzymatic Chromatin IP kit (Cell Signaling Technology, 9003) according to the manufacturer’s instructions. Briefly, crosslinking of proteins-DNA was carried out using 37% formaldehyde for 10 min at room temperature. The crosslinking was quenched by adding glycine and cells were scraped into 1 mM PIC. The suspension was centrifuged and the pellet was resuspended in buffer A + DTT + PIC and buffer B + DTT containing micrococcal nuclease. The nuclei pellet was further lysed by sonication, and the supernatant was incubated with H3K27ac antibody overnight at 4 °C with rotation. The samples then incubated with protein G magnetic beads, and DNA was eluted from the protein G magnetic beads by ChIP Elution Buffer. qRT-PCR was performed using SimpleChIP^® Universal qPCR Master Mix (Cell Signaling Technology, 88989) to detect eluted DNA. The primer sets are listed in Supplementary Table 4.