Creation of a pigment-less zebrafish for in vivo analysis of the role of Zonula Occluden-1 in photoreceptor patterning of the retina

Abstract

Cone photoreceptors of the retina, which are arranged in a precise planar mosaic array, initiate signals from specific wavelengths of light that travel to the brain and are processed to produce vision. If the retina is damaged or the precise cone array is destroyed, color vision can cease to function, as seen in a wide array of debilitating human diseases such as glaucoma and retinitis pigmentosa. The zebrafish retina was chosen as an in vivo model to study photoreceptor patterning and also to explore the abilities of the zebrafish retina to regenerate after injury. It is currently hypothesized that cell-cell interactions, such as tight junctions between photoreceptors, drive the development of the cone mosaic array. Studying such cell-cell interactions, particularly in real-time, is often hindered by the presence of pigments cells. In this study, a zebrafish lacking pigment in the body and eye was created with the intention of using it as an in vivo retinal model. This zebrafish line, currently called the Triple Mutant line, will be used to create a transgenic zebrafish line expressing a tight junction fusion protein known as GFP-ZO-1, which labels cones with GFP. The cone-specific Rx 3000 UCE promoter derived from Xenopus laevis was identified as the best candidate to drive the tight junction protein in cone photoreceptors. Future work should seek to create the transgenic line, which can then be used for in vivo studies of the role of tight junctions in the patterning and regeneration of the retina. Additionally, widespread use of this Triple Mutant could enable in vivo research on eye and general body systems of the zebrafish.