Fig. 4

Water transport of MIPfun is required for lens transparency, optics, and lens nucleus centralization. Representative lenses from adult aqp0a?/? mutants (A) (SL = 23.8 mm), aqp0a?/? mutants overexpressing MIPfun (B) (SL = 24.7 mm) or aqp0a?/? mutants overexpressing a water transport defective MIPfunN68Q (C) (SL = 25.9 mm) were imaged through the optical axis under bright field (BF) or dark field (DF) illumination. The ability to focus was tested by focusing through the lens onto a grid. A dense nuclear cataract, poor transparency in the center of the lenses, and inability to focus a grid clearly were observed in aqp0a-/-MIPfunN68Q lenses. (D) The frequency of cataract in adult fish SL > 20 mm was higher in +MIPfunN68Q compared to aqp0a?/? mutants. Refer to Supplementary Figure S1 for phenotype frequency by developmental stage. The same lenses from A to C were imaged perpendicular to the optical axis displayed the relative localization of the lens nucleus (E?G). (H) Overexpression of MIPfunN68Q in aqp0a?/? resulted in failure of the lens nucleus centralization, and the nucleus is more anteriorly localized than in aqp0a?/? at shorter SLs (P = 007 at cross sectional mean nucleus r/a at SL = 1.96 mm ± 1.5 SD) and mid SLs (P = 0.000 at cross sectional mean nucleus r/a at SL = 12.87 mm ± 1.5 SD. The slope of graph is statistically different between aqp0a?/? and mutants expressing MIPfunN68Q (P = 0.003). Scale bars = 500 µm.