Intercellular calcium signaling in a gap junction-coupled cell network establishes asymmetric neuronal fates in C. elegans
Department of Neurobiology
Medical Subject Headings
Caenorhabditis elegans; Caenorhabditis elegans Proteins; Calcium Signaling; Connexins; Gap Junctions; Neurons; Olfactory Receptor Neurons
Neuroscience and Neurobiology
The C. elegans left and right AWC olfactory neurons specify asymmetric subtypes, one default AWC(OFF) and one induced AWC(ON), through a stochastic, coordinated cell signaling event. Intercellular communication between AWCs and non-AWC neurons via a NSY-5 gap junction network coordinates AWC asymmetry. However, the nature of intercellular signaling across the network and how individual non-AWC cells in the network influence AWC asymmetry is not known. Here, we demonstrate that intercellular calcium signaling through the NSY-5 gap junction neural network coordinates a precise 1AWC(ON)/1AWC(OFF) decision. We show that NSY-5 gap junctions in C. elegans cells mediate small molecule passage. We expressed vertebrate calcium-buffer proteins in groups of cells in the network to reduce intracellular calcium levels, thereby disrupting intercellular communication. We find that calcium in non-AWC cells of the network promotes the AWC(ON) fate, in contrast to the autonomous role of calcium in AWCs to promote the AWC(OFF) fate. In addition, calcium in specific non-AWCs promotes AWC(ON) side biases through NSY-5 gap junctions. Our results suggest a novel model in which calcium has dual roles within the NSY-5 network: autonomously promoting AWC(OFF) and non-autonomously promoting AWC(ON).
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Citation: Development. 2012 Nov;139(22):4191-201. doi: 10.1242/dev.083428. Link to article on publisher's site