δ-catenin controls layer-specific transcriptional maturation of astrocytes via Zbtb20.

Coordinated maturation of diverse neural cell types drives mammalian cortical circuit development. Disruption of this coordination is a hallmark of human neurodevelopmental disorders, yet mechanisms that synchronize transcriptional maturation across cell types remain poorly understood. Here, we identify δ-catenin (Ctnnd2), a component of adherens junctions, that links cell-cell interactions to transcriptional regulation. Using single-nucleus and spatial transcriptomics, we show that δ-catenin loss disrupts transcriptional maturation across neural cell types, particularly in astrocytes. δ-catenin loss impairs acquisition of layer-specific astrocyte identities and prolongs ocular dominance plasticity, indicating impaired circuit stabilization. Mechanistically, we identify the BTB/POZ transcription factor Zbtb20, which is enriched in glial cells, as a key regulator of this process. δ-catenin loss increases Zbtb20 expression, redistributes its genome-wide binding, and dysregulates its target genes. Together, these findings support a model in which δ-catenin regulates Zbtb20-dependent transcriptional programs to establish layer-specific astrocyte identities in coordination with developing cortical circuits.