9309502 Reh The development of the eye involves several different interactions to organize the neural network of the retina and the related non-neural pigment epithelium. During early developmental stages, cells called blastomeres have the potential to later differentiate into progeny cells that can become a variety of different types. Later, the type of cell which can arise from further cell divisions becomes more restricted. Work on transplanted cells from various stages has shown that both intrinsic genetic factors and extrinsic factors in the developing environment apparently influence these cell fates to some degree. This project uses an innovative model of "transdifferentiation" and techniques of immunocytochemistry and molecular biology. The molecular factors will be examined that determine the differences arising during development between retinal neurons and retinal pigment epithelial cells. These studies involve the roles of fibroblast growth factors (FGF) and their receptor molecules as important extrinsic factors, and the role of a gene known as CASH-1 which is expressed in retinal neural but not retinal pigment epithelial cells, as an intrinsic factor in developmental determination. The results will have an impact beyond developmental neuroscience alone, to understanding formation of the visual system, and will have likely health-related applications. ***
