Bringing light into gene regulation in hematopoietic stem cells by the Mediator complex.

Hematopoietic stem cells (HSCs) are the progeny of all hematopoietic cell lineages. They have on one hand the ability to self-renew and to maintain the HSC pool and on the other hand they can differentiate into all hematopoietic lineages. During lineage differentiation, they progressively lose their ability to self-renew (1). Cell intrinsic mechanisms, like precise transcription control and epigenetic modifications, have been shown to regulate the balance between self-renewal and differentiation (2). Several transcription factors (TFs) have been identified to regulate these stem cell features. However, how these TFs are regulated during development and maintenance is poorly understood yet.