Fig. 5

Coordinated migration and expansion of glutamatergic and GABAergic neurons in the larval cerebellum. (A–I) Tracing of the glutamatergic and GABAergic lineages. Tg(UAS-E1b:NfsB-mCherry); Tg(ptf1a:Gal4VP16) fish (Tg(ptf1a:G4-U:mCherrry)) were crossed with Tg(atoh1a:EGFP) to mark the lineages of cells derived from atoh1a⁺ or ptf1a⁺ neuronal progenitors. The expression of EGFP (glutamatergic lineage) and mCherry (GABAergic lineage) was analyzed on dpf 2 (A, D, G), 3 (B, E, H), and 5 (C, F, I). Dorsal stacking views with rostral to the left (A-F), and lateral views of optical sections (G, H), and a histological section (I) are shown. (J) Schematic representation of the development of the two lineages. At 2 dpf, atoh1a⁺ glutamatergic and ptf1a⁺ GABAergic progenitors occupy, respectively, the anterior and posterior domains, of the cerebellum. From 3 to 5 dpf, atoh1a⁺ progenitors generate atoh1a:EGFP⁺ granule cells in the ML, which become Neurod⁺ immature granule cells and migrate to the granule cell layer; ptf1a:EGFP⁺ cells migrate dorsally from the VZ and become differentiated into Purkinje cells at the Purkinje cell layer. These processes generate the three cerebellar layers visible at 5 dpf. The abbreviations are defined in [Fig. 1], [Fig. 3] and [Fig. 4]. Scale bars: 50 μm (G, H, I), 100 μm (D), 200 μm (A).