Aberrant Positions of the Chemosensory Neurons in the Neurotransmitter-Release Mutant unc-13

Secretion of neurotransmitter- and neuropeptide-containing vesicles is a regulated process orchestrated by multiple proteins. Of these, mutants, defective in the unc-13 and unc-31 genes, responsible for neurotransmitter and neuropeptide release, respectively, are routinely used to elucidate neural and circuitry functions. While these mutants result in severe functional deficits, their neuroanatomy is assumed to be intact. Here, using C. elegans as the model animal system, we find that the head sensory neurons show aberrant positional layout in neurotransmitter (unc-13), but not in neuropeptide (unc-31), release mutants. This finding suggests that synaptic activity may be important for proper cell migration during neurodevelopment and warrants considering possible anatomical defects when using unc-13 neurotransmitter release mutants.