Fig. 3

FBMNs lacking Rest repression send out aberrant neurites. (A and B) Average intensity projection confocal images (dorsal views) of Tg(islet1:GFP)-expressing FBMNs at 48 hpf. Scale bar=10 µm. (A) In wild type specimens protrusions across the midline and laterally (arrows) occur from FBMNs localized in r6. By contrast, in MZrest^sbu29/sbu29 mutant specimens protrusions laterally and across the midline frequently occur from FBMNs localized in r4 and r5 (B). (C–D′) Ectopic protrusions (arrows) in mCherry-REST-VP16 mosaic embryos are primarily sent out by FBMNs expressing the construct, as indicated by mCherry expression (D′). (E–G) Average number of neurites extended in r4 (black), r5 (checkered), and r6 (white) by FBMNs in rest mutant embryos (E) and those mosaically expressing dnRest4 (F) or REST-VP16 (G). (H–J) FBMNs expressing mosaic mCherry-REST-VP16 send out ectopic protrusions in r4 and r5 that are also Map2-positive, showing that dendritic branching occurs in inappropriate locations (arrows). (K and L) Lateral views of Tg(zCREST1:membRFP)-expressing FBMNs at 24 hpf. FBMNs in MZrest^sbu29/sbu29 embryos send out long protrusions during migration (arrow). Scale bar=10 µm.