‘Transdifferentiation’ of chicken neural retina into lens and pigment epithelium in culture: controlling influences

Abstract

The in vitro transdifferentiation of chicken embryo neural retina into pigment epithelium and lens cells was investigated under a variety of experimental conditions. Our findings suggest that some aspects of the phenomena are a function of medium composition and volume, whereas others depend upon conditions which develop during culture growth. Before melanin is visible, potential pigment cells are recognized as foci within epithelialsheets which remain in contact with the dish. The final area occupied by colonies of potential pigment cells is directly proportional to bicarbonate concentration. Low total medium volume also favours formation of potential pigment cells. In contrast the extent of cells other than potential pigment cells is not related to bicarbonate and is favoured when the volume of medium is large. Accumulation of melanin within the potential pigment cell colonies is suppressed when cells are crowded together. Lentoid bodies are formed from cells which are distinct from potential pigment cells and arise in crowded situations, in association with multilayering. Another type of structure superficially resembling a lentoid is derived from cell aggregates formed during the initial establishment of cultures. The survival of these ‘aggregate bodies’ is inversely related to bicarbonate concentration. Crystallin content is unrelated to lentoid numbers. The results provide the basis for a new hypothesis concerning cytodifferentiation in this system.

Division of astroblasts and oligodendroblasts in postnatal rodent brain: Evidence for separate astrocyte and oligodendrocyte lineages

“…A classic and extreme example is the transdifferentiation of the lens primordium and primitive retinal tissue. At the appropriate time in development, the transformation of embryonic retinal cells into lens fiber cells and, vice versa, differentiation of the lens primordium into retinal tissue have both been demonstrated (Kinoshita, 1974;Itoh et al, 1975;Okada et al, 1975;Pritchard et al, 1978). The developmental potential of cells may also be altered in a tissue culture environment.…”