Some Innexin Family Members Are Required for Cold Nociception Responses Mediated by Class III Dendritic Arborization Neurons
Authors: Nicolas Nettemeyer 1; Rachel Barborek 1,2; Maddie Ward 1,3; Susan Halsell 1
Affiliations: 1) James Madison University, Harrisonburg, VA; 2) University of Washington, Seattle, WA; 3) Virginia Commonwealth University School of Medicine, Richmond, VA
Keywords: t. other (Cold Nociception ); t. other (Cold Nociception )
The class III dendritic arborization (da) neurons mediate the behavioral response of third instar larvae to noxious cold (Turner et al. 2016. Curr Biol. 26:3116). Larvae respond to noxious cold by decreasing their overall length in a manner referred to as cringing. Innexin proteins form gap junctions, and may function in electrical synapsis, development of the nervous center, or tissue morphogenesis. GAL4/UAS RNAi expression coupled with a cold behavioral response assay assessed the possible role of each of the eight Drosophila Innexin family members. Expression of innexin gene-specific RNAi’s was driven specifically in class III da neurons. When possible, more than one RNAi line was studied for each gene. Alteration of the wild-type cold behavioral response was quantified as a loss of the cringe response (non-cringing). Of the eight innexin genes, RNAi expression against innexins 1 (ogre), 2, and 5 significantly inhibited the cold nociception response with both tested RNAi lines. The requirement for Innexin 1 function was confirmed by examining the response in ogre complete loss-of-function mutants. innexins 3, 4 (zero population growth), 6, and 8 (ShakingB) showed inconsistent results between their two tested RNAi lines. In order to resolve the ambiguity, behavioral assays are underway to test double-stranded RNAi constructs for each of these genes. Finally, RT-PCR is being conducted to determine which of these genes are expressed in class III da neurons.