Genome-wide Analysis of Transcriptional Reprogramming in Mouse Models of Acute Myeloid Leukaemia

Acute leukaemias are commonly caused by mutations that corrupt the transcriptional circuitry of haematopoietic stem/progenitor cells. However, the mechanisms underlying large-scale transcriptional reprogramming remain largely unknown. Here we investigated transcriptional reprogramming at genome-scale in mouse retroviral transplant models of acute myeloid leukaemia (AML) using both gene-expression profiling and ChIP-sequencing. We identified several thousand candidate regulatory regions with altered levels of histone acetylation which were characterised by differential distribution of consensus motifs for key haematopoietic transcription factors. The integrated genome-scale analysis applied in this study represents a valuable and widely applicable approach to study the transcriptional control of both normal and aberrant haematopoiesis and to identify critical factors responsible for transcriptional reprogramming in human cancer. To monitor global expression changes during leukaemia progression for both MLL-ENL and MOZ-TIF1, we performed gene expression profiling for three biological replicates each of the lin-/kit+ bone marrow (WT), Factor-Dependent Cells Patterson-Mix cells (FDCP), MLL-ENL initiation (ME-I), MOZ-TIF2 initiation (MT-I), MLL-ENL progression (ME-L) and MOZ-TIF2 progression (MT-L) samples. Biotin-labelled cRNA from three biological replicates was generated from 250ng of total RNA and hybridized onto MouseWG-6 version 2 Expression Bead Chips.