Fig. 1. Asymmetric Numb segregation enables neural stem cells to balance self-renewal and differentiation during mouse neurogenesis. Mammalian Numb proteins localise to one side of the cell membrane in dividing neural stem (progenitor) cells and can be differentially inherited by the two daughter cells. (A) An immunofluorescent neural stem cell with Numb protein (green) localised asymmetrically. Red fluorescence indicates the chromosomes. (B) Schematic of a neural stem cell and its daughter cells, showing the localisation of Numb (green; apical localisation is shown in the neural stem cell). The daughter cell that inherits the most Numb self-renews, whereas the one that inherits less Numb becomes a neuron. Images courtesy of Weimin Zhong.