Jaeda Coutinho-Budd1, Marc R. Freeman2 and Sarah Ackerman3 1Department of Neuroscience, Center for Brain Immunology and Glia, University of Virginia, Charlottesville, Virginia 22903, USA 2Vollum Institute, Oregon Health and Science University, Portland, Oregon 97239, USA 3Department of Pathology and Immunology, Brain Immunology and Glia Center, and Department of Developmental Biology, Washington University School of Medicine, Saint Louis, Missouri 63110, USA Correspondence: sarah.ackermanwustl.edu; jaeda.coutinho-buddvirginia.edu

Molecular genetic approaches in small model organisms like Drosophila have helped to elucidate fundamental principles of neuronal cell biology. Much less is understood about glial cells, although interest in using invertebrate preparations to define their in vivo functions has increased significantly in recent years. This review focuses on our current understanding of the three major neuron-associated glial cell types found in the Drosophila central nervous system (CNS)—astrocytes, cortex glia, and ensheathing glia. Together, these cells act like mammalian astrocytes and microglia; they associate closely with neurons including surrounding neuronal cell bodies and proximal neurites, regulate synapses, and engulf neuronal debris. Exciting recent work has shown critical roles for these CNS glial cells in neural circuit formation, function, plasticity, and pathology. As we gain a more firm molecular and cellular understanding of how Drosophila CNS glial cells interact with neurons, it is clear that they share significant molecular and functional attributes with mammalian glia and will serve as an excellent platform for mechanistic studies of glial function.