Spatiotemporal Resolution of SCF Supply in Early Hematopoiesis.

Evidence suggests that hematopoietic progenitor cells self-replenish in situ over prolonged time frames, centering the question on the identity and source of growth factors maintaining HPC fidelity. In this issue of Cell Stem Cell, Comazzetto et al. (2019) suggest that normal stem and progenitor function relies on stem cell factor provided by distinct cellular sources.