The long term goal of this research is to understand the cellular mechanisms that establish the topographically organized regions of the vertebrate brain. Topographic organization involves spatial and temporal patterns of neuroblast and axon migration. A search for the molecules that might be involved in these processes, using immunofluorescent screens on rat embryo neural tissue and antibodies raised against fetal rat retina, has resulted in the identification of a ganglioside antigen recognized by a monoclonal antibody (Jones). The developmental profile of Jones binding suggests that, in the fetal and neonate brain, the Jones ganglioside is associated with the selective migration of populations of cells and cell processes. If the Jones antigen is involved in the differential control of cell and axon motility, a preferential distribution of this molecule on growth cones and/or on the substrate they contact would be expected. Dr. Constantine Paton will test this hypothesis by applying electron microscope (EM) immunocytochemical analyses to pseudopodial and filopodial contacts of cultured cells. The results obtained from these ultrastructural localization studies will increase our understanding of early brain morphogenesis. In addition, since gangliosides have been implicated in many processes of neural growth and repair, this study may contribute to the general understanding of regenerative ability in the central nervous system.
