Figure 2.

Electron microscopy shows that melanosomes do not move into the apical processes of RPE of ashen and shaker-1 mouse. Transmission EM longitudinal sections of mouse retinas (A–C) show elongated melanosomes within the apical processes of wild-type RPE that extend between the rod outer segments (ROS), whereas in ashen and shaker-1 mice melanosomes do not enter the apical processes. BM, Bruch's membrane. Oblique sections (D and E) show that many melanosomes are above the level of the adherens junctions (arrows) and extend into the apical processes between the ROS in the heterozygous (+/–, phenotypically normal) mouse (D), whereas in the homozygous (–/–) ashen mouse (E) the melanosomes remain below the level of the junctions. Bar, 2 μm.