Figure 1.

Stem cell-fate decisions in the Drosophila central nervous system.Drosophila neural stem cells, called neuroblasts, exhibit diverse stem cell behaviors. Thoracic and brain neuroblasts are eliminated by terminal division (top left), while abdominal neuroblasts undergo apoptosis (top right). Temporal controls regulate the period of neuroblast quiescence between embryonic and larval stages of development (bottom left). Certain larval neuroblasts within the inner proliferating center (IPC) of the optic lobe switch from renewing asymmetric to amplifying symmetric divisions (bottom right). Execution of these cell-fate decisions is intimately tied to neuroblast identity in time and space.