The quantitative analysis of transcriptomes derived from MLL-AF10 flox cells and MLL-AF10 (Tip60 flox/flox, Cre-ERT2) cells with or without the treatment of 4-OHT

Chromosome translocations involving the MLL gene are common rearrangements in leukemia. Such translocations fuse the MLL 5'-region in frame to partner genes , and the resultant fusion proteins can cause MLL-related leukemia. MLL-fusions activate transcription of target genes such as the HoxA cluster and Meis1, but the underlying mechanisms remain elusive. We found that the MLL-AF10 fusion recruits Tip60 to the Hoxa9 locus, where it acetylates H2A.Z, thereby promoting Hoxa9 expression. Following conditional deletion of Tip60, hypoacetylation of H2A.Z was accompanied by recruitment of Ezh2, the catalytic subunit of PRC2, suggesting that nucleosomes with hypoacetylated H2A.Z are the preferential targets of Ezh2. Our findings suggest that MLL-AF10 achieves active chromatin states by recruiting Tip60, which acetylates H2A.Z to prevent gene silencing by Ezh2. Overall design: The comprisons of transcriptomes between 4-OHT-treated and non-treated MLL-AF10 flox cells (MAflox cells) and between 4-OHT-treated and non-treated MLL-AF10 (Tip60 flox/flox, Cre-ERT2; MATIP) cells (MATIP cells).