RBP-J promotes the maturation of neuronal progenitors.

During brain development, neurons and glias are generated from neural stem cells and more limited intermediate neural progenitors (INPs). Numerous studies have revealed the mechanisms of development of neural stem cells. However, the signaling pathways that govern the development of INPs are largely unknown. The cerebellum is suitable for examining this issue because cerebellar cortical inhibitory neurons such as basket and stellate cells are derived from small Pax2+ interneuronal progenitors. Here, we show that Sox2−/Pax2+ and Sox2+/Pax2− progenitors, 2 types of interneuronal progenitors of basket and stellate cells, exist in the cerebellar white matter (WM) and that the former arise from the latter during the first postnatal week. Moreover, RBP-J promotes the neurogenesis of stellate and basket cells by converting Sox2+/Pax2− interneuronal progenitors to more mature Sox2−/Pax2+ interneuronal progenitors. This study shows a novel RBP-J function that promotes INP differentiation.