Aquaporins Have Regional Functions in Development of Refractive Index in the Zebrafish Eye Lens

Purpose: In the eye lens, cytosolic protein concentrations increase progressively from periphery to center, contributing gradient of refractive index (GRIN). Aquaporins are membrane proteins lens fiber cells that regulate water transport and adhesion interact with cytoskeletal proteins. This study investigates how these contribute proper development GRIN. Methods: Loss-of-function deletions aqp0a and/or aqp0b in zebrafish were generated using CRISPR/Cas9 gene editing. Lenses single aqp0a−/− mutants, aqp0b−/− double aqp0a−/−/aqp0b−/− mutants larval elderly adult stages measured x-ray Talbot interferometry at SPring8 Japan. The three-dimensional GRIN profiles two orthogonal cross-sectional planes each analyzed compared vivo images previous results obtained wild-type lenses. Results: Single tended show asymmetric profiles, central plateau regions shifted anteriorly. had smooth, symmetric throughout until spoke opacities appeared several extremely old samples. Double showed lower magnitude as well dips region. Conclusions: These findings suggest Aqp0a Aqp0b have region-specific functions lens: is active peripherally, regulating centralization region, this function cannot be compensated for by Aqp0b. either or required formation reach its maximum mature