Astrocyte specification in the mouse septum is shaped by both developmental origin and local signals.

Astrocyte specification during development is influenced by both intrinsic and extrinsic factors, but the precise contribution of each remains poorly understood. Here we show that mouse septal astrocytes derived from Nkx2.1- and Zic4-expressing progenitor zones are primarily allocated into the medial septal and lateral septal nuclei, respectively.