Ectopically differentiated RGCs induce retinal lamination defects. (A) Control retina at 96 hpf with RGCs, photoreceptors (PRs; magenta), and bipolar cells (BCs; green) labeled. Nuclei are stained with DRAQ5 (blue). HS, heat shock. (B) Organizing role of ectopic RGCs. Asterisks, clusters of ectopic RGCs organizing later-born bipolar cells. (C) Lamination defects after mosaic expression of ath5:mKate2-aPKC-CAAX. Asterisks, area with the lamination defect. (D) Retinal lamination upon aPKC-CAAX overexpression in the absence of RGCs. The ath5:gap-RFP reporter is still expressed in other cell types when RGCs are absent in the ath5 morphant. No optic nerve is seen. (A–D) Dashed lines delimit the apical side or indepedent areas of lamination. Bars, 50 µm.