Lineage-specific transcription factors in multipotent hematopoietic progenitors: a little bit goes a long way.

Basal expression of lineage-specific transcription factors (TFs) in multipotent hematopoietic progenitor cells (HPCs) plays a pivotal role in normal hematopoiesis. Indeed, the interplay between lineage-specific TFs and chromatin modifying or remodeling complexes allows chromatin modifications at specific hematopoietic loci and promotes transcriptionally prone conformations. During hematopoiesis, the expression of various lineage-specific genes can be preceded by their potentiation i.e., by chromatin activation, in progenitor cells. Gene potentiation appears to counterbalance epigenetic silencing of lineage-specific genes in early progenitors, while maintaining an accessible chromatin conformation in the lineage pathway selected. Herein, we discuss the impact of lineage-specific TFs on gene potentiation and priming in normal hematopoiesis, and emphasize the complementary role of locus control region (LCR) or LCR-like structures and promoter regions in gene-specific potentiation events.