THE ZEBRAFISH ULTRAVIOLET CONE OPSIN REPORTED PREVIOUSLY IS EXPRESSEDIN RODS

Purpose. To examine expression of the zebrafish ultraviolet cone opsin pigment in goldfish and zebrafish retinas. Methods. Digoxigenin-label ed cRNA probes were prepared by run-off transcription from plasmids co ntaining cDNAs for zebrafish ultraviolet opsin, goldfish ultraviolet c one opsin, and goldfish rod opsin. Probes were hybridized to cryosecti ons of retina and visualized with immunocytochemistry. Results. The ze brafish ultraviolet opsin probe hybridized selectively to rod photorec eptors, but not to ultraviolet cones or any other cone type, in both z ebrafish and goldfish retinas, and the pattern of expression was ident ical to that of the goldfish rod opsin probe. The goldfish ultraviolet opsin, in contrast, hybridized to ultraviolet cone photoreceptors in both goldfish and zebrafish. Conclusions, The cDNA previously identifi ed by Robinson et all as zebrafish ultraviolet opsin is not a cone ops in but is likely to be a rod opsin.