A top-NOTCH way to make astrocytes.

During mammalian nervous system development, neural precursor cells first generate neurons and then switch to astrocytes. In this issue of Developmental Cell, Namihira and colleagues show that committed neuronal precursors and young neurons promote the production of astrocytes from the remaining neural precursors by activating Notch signaling, leading to demethylation and upregulation of astrocyte-specific genes via cytokine-mediated JAK-STAT signaling.