Immunoprecipitation was performed as described previously (24 (link)). Briefly, cells were washed by ice-cold PBS for 3 times, then lysed by NP40 cell lysis buffer (Invitrogen, FNN0021) supplemented with protease inhibitor cocktail (Thermo Scientific, 78430) and PMSF (Santa Cruz, sc-482875) on ice for 30 min. Cell lysates were clarified by centrifugation at 14 000 g for 10 min at 4°C. The lysates were incubated with 2 μg of anti-EZH2 antibody (CST, 5246S), or normal rabbit IgG (Millipore, 12-370) at 4°C overnight. In the meantime, Dynabeads (Invitrogen, 10004D) were incubated with 5% BSA diluted in PBS to reduce the non-specific background at 4°C overnight. Next, the antibody-lysates mixture was added to the Dynabeads at 4°C for 4 h. The complex was washed with ice-cold NP40 lysis buffer for three times before the complex was eluted in 2× Laemmli sample buffer (Bio-Rad, 1610737) at 95°C for 5 min.