How transcription factors program chromatin—Lessons from studies of the regulation of myeloid-specific genes

Hematopoietic stem cells exhibit a multi-lineage gene expression program, and this expression program is either maintained when these cells self-renew, or re-programmed when they differentiate. Both processes require the regulated expression of sequence-specific transcription factors and their interaction with the epigenetic regulatory machinery which programs the chromatin of hematopoietic genes in a cell type specific fashion. This article describes recent findings on the complexity of these molecular interactions and their consequences with respect to the regulation of cell fate decisions. We also describe recent findings from studies of genes expressed in the myeloid lineage (Pu.1 and csf1r) which highlight some of the molecular principles governing cell fate decisions at the epigenetic level.