The glia of Caenorhabditis elegans

Glia have been, in many ways, the proverbial elephant in the room. Although glia are as numerous as neurons in vertebrate nervous systems, technical and other concerns had left research on these cells languishing, whereas research on neurons marched on. Importantly, model systems to study glia had lagged considerably behind. A concerted effort in recent years to develop the canonical invertebrate model animals, Drosophila melanogaster and Caenorhabditis elegans, as settings to understand glial roles in nervous system development and function has begun to bear fruit. In this review, we summarize our current understanding of glia and their roles in the nervous system of the nematode C. elegans. The recent studies we describe highlight the similarities and differences between C. elegans and vertebrate glia, and focus on novel insights that are likely to have general relevance to all nervous systems.