Fig. 6. Retinal lamination and RPE structure are disrupted in Shroom2-SPL-MO morphants. (A,D) Histological analysis indicated that the most severely affected Shroom2-SPL-MO morphants had prominent retinal lamination defects and increased numbers of pyknotic nuclei in their retinas when compared with stage-matched 5 bp-MM MO-injected controls. (B,E) Less severely affected morphants showed significantly better retinal lamination, as demonstrated here via actin localization in optical sections. Additionally, phalloidin staining revealed the regular appearance of the RPE in control embryos (B,b') in contrast to that in Shroom2-SPL-MO morphants (E,e') in which the RPE invaded the retina with numerous apical protrusions. (C,F) Further examination with TEM highlights these apical protrusions and also indicates that melanosome morphology and distribution are disrupted in Shroom2-SPL-MO morphants. Melanosomes appear clumpy and are not limited to the apical cell surface. Red lines delimit apical (left) and basal (right) surfaces of the RPE.