Notch in the niche.
Gering M., Patient R.
Notch signaling is essential for hematopoietic stem cell (HSC) formation during embryogenesis, and hitherto it was also thought to be required for HSC maintenance. However, in this issue of Cell Stem Cell, Maillard et al. (2008) demonstrate rather conclusively that inactivation of the Notch pathway in HSCs does not interfere with their self-renewal.