Fig. 7. Ultrastructural analysis of Shroom2 RPE. (A,B) High magnification TEM allowed further analysis of Shroom2-SPL-MO morphant melanosome morphology. (A) Control RPE contained smooth-edged melanosomes of varying size and black because of melanin accumulation. (B,b') Two representative regions of Shroom2-SPL-MO morphant RPE. Melanosome number was similar to controls; however, melanosome morphology was severely abnormal. Melanosomes contained numerous vesicular structures, most of which appeared to have not coalesced into a single structure resulting in a `bunch of grapes' morphology. (C) Measurement of relative melanosome area of melanosomes in Shroom2-SPL-MO morphants and controls, indicated that the melanosome aggregates of Shroom2 morphants were almost 90% larger in area than controls. (D) Shroom2-SPL-MO morphant melanosomes were also found to have highly irregular surfaces, with a relative roundness value of over 1.7 and compared with a value of 1.36 for control melanosomes (a perfect circle has a roundness of 1.00).