Structural changes in retinal pigmented epithelium of Rivulus marmoratus Poey embryos during development

In Rivulus marmoratus development of retinal pigmented epithelium (RPE) parallels that of retinal photoreceptors. Although structurally functional by mid-incubation the full complex structure is not achieved even when the yolk-sac is absorbed (3-days post-hatched). Melanogenesis is evident at 0.2 incubation with premelanosomes present up to three days after hatching. The distribution of junctional complexes, basal membrane foldings and coated-pits throughout development is noted. Myeloid bodies, already present at mid-incubation, appear initially as single lenticular-shaped structures which later may form whorls, or coalesce around oil droplets, glycogen clusters or phagosomes thereby giving rise to myeloid patterns characteristic of a mature RPE. The functional significance of these changes is discussed.