Lineage-specific enhancers activate self-renewal genes in macrophages and embryonic stem cells

Genetic programming for self-renewal Instead of repopulating themselves from tissue-resident stem cell pools like most types of differentiated cells, tissue macrophages maintain themselves by self-renewing. The underlying genetic programs that allow for this, however, are unknown. Soucie et al. now report that in macrophages at homeostasis, a pair of transcription factors (MafB and c-Maf) bind to and repress the enhancers of genes regulating self-renewal. When macrophages need to replenish their stocks, for example in response to injury, they transiently decrease MafB and c-Maf expression so they can self-renew. A parallel pathway also operates to control the self-renewal of embryonic stem cells. Science , this issue p. 10.1126/science.aad5510