RUI: Use of Transgenic Xenopus Embryos to Study Cell Specification in Eye Development

Ithaca College, Ithaca NY

Investigators

Abstract

Cell specification in eye development Eyes in vertebrates develop from cells in two regions of the forebrain, and these cells specialize (or differentiate) to generate many cell types. The cell types include photoreceptor cells (which detect light), many types of neural cells (which integrate signals from photoreceptor cells and send signals to the brain), and several types of supporting cells. The mechanisms by which regions of the brain become specified to form eyes, and cells in these region become specified to form different cell types, are not well understood. The proposed research will examine eye development in a model laboratory organism, the frog Xenopus laevis. Cells within the developing eyes communicate by releasing specific signaling proteins; these proteins bind to receptors on other cells, influencing cell determination. One group of signaling proteins, called FGFs, is used in several processes during eye development. FGFs can bind to, and activate, any of four different FGF receptors (FGFRs), but it is not clear whether activation of specific FGFRs affects cell differentiation in the eye. Experiments will be conducted to test the hypothesis that activation of different FGFRs causes eye cells to differentiate in different ways. Inhibitory FGFRs will be expressed in the developing eye; it will then be possible to compare the effects of blocking signaling through, say, FGFR-1 with the effects of blocking other FGFRs. This analysis will show whether different FGFRs play distinct roles in eye development. The experiments will utilize recently developed transgenic technology in frogs, which makes it possible to introduce specific genes into frog embryos. The introduced genes will consist of DNA that directs the gene to be expressed only in the eye, coupled to DNA encoding an inhibitory FGFR. . These studies will lead to a better understanding of the mechanisms by which vertebrate eyes develop, and which processes may be disrupted when eyes develop abnormally. Finally, comparison of eye development in different organisms will contribute to a better understanding of how eyes have evolved. Undergraduate students will be strongly involved in the proposed research. This research will thus serve, in part, to train the next generation of scientists.