Abstract
BACKGROUND: Adult hematopoietic stem cells (HSCs), the ideal system for regenerative research, were isolated at single cell levels decades ago, whereas studies on embryonic HSCs are much more difficult. METHODS: Zhou et al identified a new pre-HSC cell surface marker, CD201, by which they isolated pre-HSCs at single cell levels for further analyses. RESULTS: The novel expression pattern of HSC development is revealed, including the fundamental role of mammalian targets of rapamycin (mTOR) signaling pathway in HSCs emergence, and the repopulation potential of S/G2/M phase pre-HSCs. CONCLUSIONS: Deeper understandings of the cellular origin and developmental regulatory network of HSCs are essential to develop new strategies of generating HSCs in vitro for clinical application.