A class of cells found in the nervous system, though not nerve cells themselves is called glia, from their early presumed adhesive glue-like role to hold cells together. These glial cells are now known to be important for many aspects of normal function in the brain. Glial cells and their associated products participate in fundamental interactions which underline the development and organization of the nervous system. Insects are widely used as model system for development, and in insects the first antigen associated with glial cells was a glycoprotein compound called glionexin or GX, identified in the cricket. Features of its distribution, spatial and temporal expression, and preliminary functional tests suggested GX is involved in neural development as an adhesion/recognition molecule. This work uses antibody probes and microsequence analysis to screen genetic cDNA libraries from embryonic crickets and adult Drosophila flies, where we have a lot of genetic information, to isolate and sequence the gene encoding GX. Identification of the gene will allow new tests for function of this compound, which in turn will be important for understanding the complex interactions that guide nerve cell outgrowth during development and regeneration. The work may lead to better understanding of the evolution of cell adhesion macromolecules, and will have impact on developmental biology as well as neuroscience.
