Oncofusion protein AML1-ETO targets ERG factor binding sites in AML

ERG has been identified as an essential factor for the function and maintenance of adult hematopoietic stem cells and high ERG expression is a negative prognostic marker for treatment outcome in AML. The molecular function of ERG and its interplay with other factors is however largely unknown. Here we demonstrate that ERG has cell type specific distributions in normal CD34+ myeloid progenitors and in AML cells and identify ERG as a potential pioneering protein for binding of oncofusion protein complexes. In addition, we identify H3 acetylation as the epigenetic mark preferentially associated with ERG binding. This intimate connection between ERG binding and H3 acetylation implies that one of the molecular strategies of the oncofusion proteins PML-RARa and AML1-ETO could involve the targeting of histone deacetylase activities to ETS factor bound hematopoietic regulatory sites. Examination of AML1-ETO, RUNX1, CBFb, HEB, FLI1 and ERG binding sites (ChIP-seq) in leukemic and normal hematopoietic cells, association with chromatin modifications and expression (RNA-seq) analysis of an AML1-ETO expressing cell line (SKNO-1)