A cellular and regulatory map of the GABAergic nervous system of C. elegans

Abstract

Neurotransmitter maps are important complements to anatomical maps and represent an invaluable resource to understand how signals are transmitted throughout the nervous system and how a nervous system is developmentally patterned. We report here a comprehensive map of neurons in the C. elegans nervous system that contain the neurotransmitter GABA, revealing twice as many GABA-positive neuron classes as previously reported. We define previously unknown glia-like cells that reuptake GABA, as well as \"GABA reuptake neurons\" which do not synthesize GABA but take it up from the extracellular environment. We used the map of GABA-positive neurons for a comprehensive analysis of transcriptional regulators that define the GABA phenotype. We synthesize our findings of specification of GABAergic neurons with previous reports on the specification of glutamatergic and cholinergic neurons into a nervous system-wide regulatory map which defines neurotransmitter specification mechanisms for more than half of all neuron classes in C. elegans.