ChIP experiments were performed using ~4µg a-Mll1 antibody for 1E8 cells ; ~2ug a-H3K4me1/2/3 for 2E7 cells according to standard protocols. Crosslinking of the cells was performed with 1% PFA for 10 minutes, while ChIPed DNA was purified by Qiaquick PCR purification Kit (Qiagen). Libraries were prepared with the Illumina TruSeq protocol according to the manufacturer's protocol.