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Figure 2. Transgenic expression of WT and mutated human ABCA4 in X. laevis tadpoles. (A and B) Cryosections of the retina from 2-week-old tadpoles expressing human ABCA4 were immunostained with anti-ABCA4 Rim 3F4 antibody and subsequently visualized with goat anti-mouse antibody conjugated to Alexa Fluor 488 (green). The sections were stained additionally with Texas Red—WGA (red) to label the photoreceptor outer segments (A). The nuclei in both sections were stained with DAPI (blue). Human ABCA4 is recognized by 3F4 monoclonal antibody and found exclusively in the ROS rims as shown by the yellow signal (marked with arrow). (C–L) Microphotographs of 2-week-old X. laevis tadpoles expressing R602W (C and D), [L541P; A1038V] (E and F), L541P (G and H), A1038V (I and J) and C1490Y (K and L). Rod photoreceptors expressing each of the mutant proteins, except A1038V, demonstrated localization of the transgenic protein to the rod inner segment and cell body. Misfolded proteins are homogenously distributed in the inner segments and cell bodies, although the presence of fine aggregates was noted for L541P. Mutation A1038V does not influence the localization of ABCA4 and the mutant protein was found in the ROS. OS, outer segments; IS, inner segment; N, nucleus. |
