Fig. 1.

crb2b^e40 mutants are homozygous viable and develop normal eyes. (A) Schematic illustration of the long and short isoforms of Crb2b, Crb2b-lf and Crb2b-sf. Green rectangles, EGF-like domains; light blue hexagons, domains with similarity to the globular domain of laminin A (LamG domain). Bars above the protein indicate the regions used as antigens for anti-Crb antibodies. In the crb2b^e40 allele, a T to A transversion translates to an early stop codon at amino acid position 44 of the protein, resulting in truncated Crb2b-lf. (B,C) Brightfield images of WT (B) and crb2b^e40 (C) zebrafish larvae at 5 dpf. Mutant larvae have overall normal appearance. (D,E) Transverse retinal sections stained with Toluidine Blue show normal lamination of the retina of crb2b^e40 (E) larvae in comparison to WT (D) at 5 dpf. Asterisk denotes the optic nerve. GCL, ganglion cell layer; INL, inner nuclear layer; ONL, outer nuclear layer; RPE, retinal pigment epithelium. (F–G′) Confocal images of transverse retinal sections of larvae at 3 dpf stained with rabbit anti-Crb2b^e8e9 in the Tg(bactin:mRas-EGFP) background. Crb2b is detected in the IS of WT PRCs (F,F′, white arrowheads), but not in crb2b^e40 mutant PRCs (G,G′). White dashed lines mark the position of the outer limiting membrane. Scale bars: (B,C) 1 mm; (D,E) 100 µm; (F–G′) 5 µm.