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Fig. 10
RA signaling continues in juvenile retinas and the signaling domain includes red opsin+, LWS1+ cones.
Sections of retina from one-month old fish are shown, with ventral pole at bottom of images. A. Immunocytochemistry to reveal YFP signal and DAPI in a section from RARE:YFP retina. Arrows indicate YFP signal in the outer nuclear layer, corresponding to the location of cone photoreceptors. B. In situ hybridization for topaz-YFP mRNA in a section from a RARE:YFP retina. C and D. LWS:PAC(H) were crossed with RARE:YFP and doubly transgenic juvenile retina sections were examined for RFP, GFP, and YFP fluorescence. Although YFP and GFP cannot be fully resolved, the YFP+ signaling domain coincides with the GFP (LWS1) expression domain. The GFP expression domain (reporting LWS1) is designated by dashed arc (C and D), while the YFP domain (reporting RA signaling) is between the dashed straight lines (D). E. Sections from RARE:YFP juvenile retinas were stained with antibodies for YFP, ZPR1 (labels red- and green-sensitive cones), and DAPI; merged image is shown. Colabel of YFP and ZPR1 is yellow. Arrows indicate ZPR1+ cones that are YFP+. F. Sections from RARE:YFP juvenile retinas were stained with antibodies for YFP, red opsin (pan-LWS), and DAPI; merged image is shown. Arrows indicate red opsin+ cone outer segments that are continuous with YFP+ cell bodies. G. Dual in situ hybridization for topaz-YFP (purple) and LWS1 (red/pink) mRNA in a section from one-month old RARE:YFP retina. Arrows indicate examples of some of the colabeled cones. Scale bar in A = 25 µm; scale bar in C (applies to B-G) = 25 µm; v, ventral; d, dorsal.