Ultrastructural changes of cone and rod photoreceptors upon ablation of <i>Ranbp2</i> in cones at P20.

<p>(<b>A</b>) Ultrastructural image of rod and cone photoreceptors outer and inner segments of <i>HRGP-cre:Ranbp2^+/−</i> (+/−). All structures look unremarkable. (<b>B–E</b>) Representative ultrastructural images of multiple features rod and cone photoreceptors outer and inner segments of <i>HRGP-cre:Ranbp2^−/−</i> (−/−). (<b>B</b>) shows the collapse of the cone outer segment and formation of a large electron lucent area, (<b>C</b>) shows extended discs and partial erosion of cone outer segment, (<b>D</b>) shows the accumulation of amorphous electron dense material at the connecting cilium of a cone photoreceptor, (<b>E</b>) shows the formation of electron lucent areas in the inner segment of a cone photoreceptor. White stars, euchromatic nuclei of cone photoreceptors. (<b>A′–E′</b>) are magnifications of boxed areas in <b>A–E</b> showing the aforementioned pathological features. (<b>F</b>) Synaptic pedicles of cones with normal morphology of <i>HRGP-cre:Ranbp2^+/−</i> (+/−). (<b>G</b>) Multi-lamellar body with electrodense material in a cone synaptic pedicle of <i>HRGP-cre:Ranbp2^−/−</i> (−/−). (<b>H</b>) Electron lucent area surrounding subcellular debris in a cone synaptic pedicle of <i>HRGP-cre:Ranbp2^−/−</i> (−/−). <b>F′–H′</b> are magnified images of boxed areas in <b>F–H</b>. (<b>I</b>) Synaptic spherule of a rod photoreceptor containing unremarkable mitochondria (black arrows) in <i>HRGP-cre:Ranbp2^+/−</i> (+/−). (<b>J</b>) Synaptic spherule of a rod photoreceptor with abnormal mitochondria (black arrows) containing disorganized cristae and electron lucent areas in the matrix in <i>HRGP-cre:Ranbp2^−/−</i> (−/−). Scale bars = 5 µm (<b>A–E</b>), 1 µm (<b>A′–E′</b>), 500 nm (<b>F–H</b>) and 200 nm (<b>F′–H′</b>).