- Lim MA, Chitturi J, Laskova V, Meng J, Findeis D, Wiekenberg A, Mulcahy B, Luo L, Li Y, Lu Y, Hung W, Qu Y, Ho CY, Holmyard D, Ji N, McWhirter R, Samuel AD, Miller DM, Schnabel R, Calarco JA, Zhen M. Neuroendocrine modulation sustains the C. elegans forward motor state. ELife. 2016 Nov 18;5. PMID: 27855782 [PubMed]. PMCID: PMC5120884.
Neuromodulators shape neural circuit dynamics. Combining electron microscopy, genetics, transcriptome profiling, calcium imaging, and optogenetics, we discovered a peptidergic neuron that modulates C. elegans motor circuit dynamics. The Six/SO-family homeobox transcription factor UNC-39 governs lineage-specific neurogenesis to give rise to a neuron RID. RID bears the anatomic hallmarks of a specialized endocrine neuron: it harbors near-exclusive dense core vesicles that cluster periodically along the axon, and expresses multiple neuropeptides, including the FMRF-amide-related FLP-14. RID activity increases during forward movement. Ablating RID reduces the sustainability of forward movement, a phenotype partially recapitulated by removing FLP-14. Optogenetic depolarization of RID prolongs forward movement, an effect reduced in the absence of FLP-14. Together, these results establish the role of a neuroendocrine cell RID in sustaining a specific behavioral state in C. elegans.