Neuron‐glia interactions and glial enzyme expression in the mouse cerebellum

Realization of genetic programs for morphogenesis and differentiation in nervous systems requires conditions and signals resulting largely from cell interactions. Many of these depend on surface-contacts between homotypic or heterotypic cells; others involve cell reactions with extracellular matrix materials (ECM), or with hormones and trophic factors; still others require both cell contact and environmental signals. As the full scope of these processes comes to light, the concept of communication in neural development is acquiring new content and significance. Interest increasingly is drawn to the detailed molecular and ultrastructural basis of these interactions in histological patterning of cells and phenotypic expression. Studies on glia cells are revealing new aspects of their partnership with neurons. Studies on ECM aim to unravel the formation of these cell products and how they, in turn, modulate cell properties and behavior. In all of this, the unifying theme is the cell surface, because of its strategic role in environmental surveillance, morphogenetic cell-cell recognition, intercellular communication, regulation of cell growth, and gene expression. The papers in this symposium are thematically linked by this central concept. They discuss the significance of cell interactions in neurodevelopment and spotlight new directions of research in this area.