Wnt signalling meets epigenetics
The Wnt signaling pathway is required for the proper function of hematopoietic stem cells (HSCs), but its level is subject to strict regulatory control. Too much Wnt signaling leads to exhaustion of HSCs due to enhanced differentiation and loss of self-renewal. Recent work from several laboratories has indicated the complex mechanisms that are involved in normal and malignant regulation of hematopoiesis by Wnt signals. Very recently, epigenetic changes that modify the activation of genes, but not their DNA sequence, have been implicated as well. That is, specific deletion of the epigenetic regulator of histone methylation, Sirtuin 6 in blood cells, increases Wnt signaling. Here, I will briefly discuss these novel insights into Wnt signaling and HSCs.