Fig. 4

The Tg(LCR^RH2-RH2-2:GFP)^pt115-c line expresses GFP in the green cones, hatching gland, and optic tectum. (A and B) Bright field (A) and stereo-fluorescence (B) imaging shows GFP signals in the retina at 4 dpf. The top fish is a wildtype larval control, and the bottom is a Tg(LCR^RH2-RH2-2:GFP)^pt115-c transgenic larva. (C) There are about one dozen GFP positive cells on each side of the brain in the optic tectum region at 4 dpf (arrows). (D) A confocal image illustrates the extensive cell processes of the GFP-positive cells in the optic tectum, suggesting that they are neurons (arrowheads for the cell bodies). (E and F) Confocal imaging of the cross sections of the 4-dpf brain revealed that the GFP positive cells in the optic tectum are in the superficial regions. Insets show a magnified superficial region of the optic tectum (OT) and the arrowheads indicate the cell bodies of GFP positive cells. The nuclei were labeled with TO-PRO. Actin was labeled with phalloidin in blue. (G–J) GFP expression is present in the photoreceptor layer of the entire retina at 5 dpf and 1 mpf. A-P and D-V arrows indicate anterior-posterior and dorsal–ventral directions, respectively. (K and L) At 9 mpf, the entire retina maintains strong GFP expression, except for a small ventral retinal region (arrowhead, L). (M and N) Only green cones in 8-mpf adult retina express GFP. The double cones (red) were visualized by the zpr1 antibodies. M shows a vertical section and N shows a transverse section.