PT  - JOURNAL ARTICLE
AU  - Alessia Caramello
AU  - Christophe Galichet
AU  - Karine Rizzoti
AU  - Robin Lovell-Badge
TI  - Dentate gyrus development requires a cortical hem-derived astrocytic scaffold
AID  - 10.1101/2020.06.11.145672
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.06.11.145672
4099  - http://biorxiv.org/content/early/2020/10/11/2020.06.11.145672.short
4100  - http://biorxiv.org/content/early/2020/10/11/2020.06.11.145672.full
AB  - During embryonic development, radial glial cells give rise to neurons, then to astrocytes following the gliogenic switch. Timely regulation of the switch, operated by several transcription factors, is fundamental for allowing coordinated interactions between neurons and glia. We deleted the gene for one such factor, SOX9, early during mouse brain development and observed a significantly compromised dentate gyrus (DG). We dissected the origin of the defect, targeting embryonic Sox9 deletion to either the DG neuronal progenitor domain or the adjacent cortical hem (CH). We identified in the latter previously uncharacterized ALDH1L1+ astrocytic progenitors, which form a fimbrial-specific glial scaffold necessary for neuronal progenitor migration towards the developing DG. Our results highlight an early crucial role of SOX9 for DG development through regulation of astroglial potential acquisition in the CH. Moreover, we illustrate how formation of a local network, amidst astrocytic and neuronal progenitors originating from adjacent domains, underlays brain morphogenesis.Competing Interest StatementThe authors have declared no competing interest.