Journal of Neuroscience, Vol 6, 1885-1896, Copyright © 1986 by Society for Neuroscience
An in vitro model of proliferation and differentiation of the chick retina: coaggregates of retinal and pigment epithelial cells
G Vollmer and PG Layer
Pigment epithelial (PE) cells exert a pronounced organizing effect when
added to embryonic day (E) 5-6 chick retinal cells in a reaggregation
system such that after a period of 14-21 d of culture, the main layers of
an intact E10-E14 retina are reconstructed (Vollmer et al., 1984). In the
present study we investigated the time course of the formation of
retina-like structures in retinal-pigment epithelial aggregates, in
particular, the fate of the PE cells and their influence on processes of
differentiation within the aggregates. PE cells first form a core in the
center of the aggregates and migrate to the periphery at later stages. The
PE core affects the organization of proliferation and differentiation,
phenomena that were monitored using 3H-thymidine autoradiography and AChE
histochemistry, respectively. A double- staining procedure combining both
techniques on the same section is described. Soon after aggregation, a
matrix zone and a zone of differentiated cells are formed. At later steps,
proliferation becomes gradually restricted to a narrow band within the
aggregates comparable to the in vivo situation. The spatiotemporal pattern
of withdrawal from mitosis resembles that of the in vivo retina.
Proliferation in aggregates is sustained over a longer period with PE, as
compared with aggregates formed by retinal cells alone. AChE staining in
aggregates in the presence of PE shows a layered appearance, while there is
only crude sorting-out of labeled and unlabeled cells in aggregates
composed of retinal cells only. The basis of PE cell action as well as the
relevance of this in vitro system for understanding normal eye development
are briefly discussed.