Glial cells are the most abundant cell type in the vertebrate nervous system, yet their role during the development of the nervous system is not well understood. Our studies demonstrate the importance of glia in specifying precise neural connectivity in vivo. These findings, however, were limited to the synapses formed between AIY and RIA. What other roles do glial cells play in orchestrating the development of neural circuits in the nematode brain?
We have observed that there are at least nine other circuits that form synapses in the glia-specified coordinate where AIY innervates RIA. We are currently exploring the glial requirement for the development of these circuits by ablating the glia (using genetic and laser ablations methods). We are also identifying the molecular cues that could be used by glia in directing the innervation of the circuits in this region. Our preliminary data suggests that glia employ different signaling cues to orchestrate the innervation of multiple circuits. Therefore, we are currently employing forward and reverse genetic approaches to identify the molecular pathways activated by glia in directing the innervation of these glia-dependent circuits. Given the evolutionary conservation of glial cells, the developmental and molecular events uncovered in these studies could be conserved in higher organisms.