Chromatin was harvested and ChIPs were performed as described (Mandoli A, GDATA, 2014). ChIP-seq libraries were prepared from precipitated DNA of 5 million cells (5-8 pooled biological replicas) for MLL, or from 1 million cells for the histone tail modifications. End repair was performed using Klenow and T4 PNK. A 3’ protruding A base was generated using Taq polymerase and adaptors were ligated. The DNA was loaded on E-gel and a band corresponding to ~300 bp (ChIP fragment + adaptors) was excised. The DNA was isolated, amplified by PCR and used for cluster generation and sequencing on the HiSeq 2000 (Illumina).