Dr. Spiegel plans to continue his research on the biochemistry and morphology of cell adhesion during early sea urchin development using the living sea urchin embryo as well as cultured cell types. This research has the following specific aims: A. To define micromere specific proteins. B. Using the information obtained in A. to ask whether an animal- vetegal polarity of these proteins exists and is set up in the ovary, egg or cleavage stages and whether it is a general phenomenon. C. To use the reagents generated from A. (monoclonal antibodies) to ask whether one can specifically perturb the system in order to define the function(s) of these proteins in development. Specific experimental approaches include: the use of monoclonal and polyclonal antibodies and of lectin-binding to study the appearance, cellular distribution, and function of these specific proteins; and the use of various inhibitors to block gastrulation. The proposed research will involve Nomarski and fluorescence microscopy, electron microscopy, antibodies, SDS- PAGE electrophoresis, lectins, surface iodination, and cell culture. %%% During the development of the new individual the fertilized egg divides many times to form a multicellular embryo. These embryonic cells undergo considerable rearrangements of position with respect to one another by changing their cell-cell adhesions and by changes in motility. The morphological and molecular basis of the changes in cell adhesion which occur in early development is one of the most important problems in developmental biology. The sea urchin embryo is a model system for studying such cell- cell interactions since the embryo can be dissociated into a cell suspension which can reaggregate to form an almost normal looking embryo. Dr. Spiegel will investigate the origin and development of a specific cell type, the micromere, in the 16-cell stage sea urchin embryo. This cell type ultimately gives rise to the skeleton. He will prepare and use antibodies to micromere cell surface molecules to carry out these studies.
