DNA and RNA samples from the B1.3 Eed−/− and WT ES cell lines (26 (link)) were from Amanda Fisher's laboratory (Lymphocyte Development Group, MRC, London, UK).
MEF cells were isolated from E13.5 Ezh2 flox/flox;ROSA26-CreERT2 mouse embryos and then infected with the pBABE-hygro p53-DD retroviral construct (addgene 9058) to generate p53-DN immortalized MEFs (iMEFs). iMEFs were grown in Dulbecco's modified Eagle's medium (Gibco, 11960-044) with 10% fetal bovine serum (PAA, A15-101), 2 mM glutamine (PAA M11-006) and 1% MEM Non-essential amino acids solution (Gibco 11140-035) at 37°C in 5% CO2. For conditional Ezh2 deletion, iMEFs were incubated with 4-hydroxytamoxifen (Sigma, T176) at a final concentration of 1 μM.