The Zpr-3 antibody recognizes the 320-354 region of Rho and labels both rods and green cones in zebrafish

Retinal markers with high quality and specificity are important for the observation of pathologic changes of retinal cells during retinal development, degeneration, and regeneration. Zpr-3 is a mouse monoclonal antibody with uncharacterized antigen usually used to label rod photoreceptors. In this study, we provided evidence to demonstrate that the antigen gene of zpr-3 is rho, which encodes the rod opsin, and the exact epitope of zpr-3 is the 320-354 region of Rho protein. More importantly, our immunofluorescence assays indicated that zpr-3 labels both the outer segments of rods and green-cones on zebrafish retinal sections, probably due to the cross-reaction with the green-cone opsin. Our work is valuable for the scientific community to interpret the experimental data involving the zpr-3 antibody.