Engrailed Alters the Specificity of Synaptic Connections ofDrosophilaAuditory Neurons with the Giant Fiber
Year: 2014
Type: article
Abstract: We show that a subset of sound-detecting Johnston's Organ neurons (JONs) in Drosophila melanogaster, which express the transcription factors Engrailed (En) and Invected (Inv), form mixed electrical and chemical synaptic inputs onto the giant fiber (GF) dendrite. These synaptic connections are detected by trans-synaptic Neurobiotin (NB) transfer and by colocalization of Bruchpilot-short puncta. We then show that misexpressing En postmitotically in a second subset of sound-responsive JONs causes them to form ectopic electrical and chemical synapses with the GF, in turn causing that postsynaptic neuron to redistribute its dendritic branches into the vicinity of these afferents. We also introduce a simple electrophysiological recording paradigm for quantifying the presynaptic and postsynaptic electrical activity at this synapse, by measuring the extracellular sound-evoked potentials (SEPs) from the antennal nerve while monitoring the likelihood of the GF firing an action potential in response to simultaneous subthreshold sound and voltage stimuli. Ectopic presynaptic expression of En strengthens the synaptic connection, consistent with there being more synaptic contacts formed. Finally, RNAi-mediated knockdown of En and Inv in postmitotic neurons reduces SEP amplitude but also reduces synaptic strength at the JON-GF synapse. Overall, these results suggest that En and Inv in JONs regulate both neuronal excitability and synaptic connectivity.
Source: Journal of Neuroscience
Institution: University of Puerto Rico System
Language: English
Subfield: Cellular and Molecular Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: hybrid
Funders: National Science Foundation, U.S. Department of Defense, National Institutes of Health, Directorate for Biological Sciences, National Institute of General Medical Sciences, National Institute of Neurological Disorders and Stroke, National Institute of Child Health and Human Development, National Institute on Minority Health and Health Disparities
Awards: Engrailed targets and the control of synaptic circuits in Drosophila, Fluorender: An Imaging Tool for Visualization and Analysis of Confocal Data as Ap, G4986506763, MRI: Procurement of a Shared Confocal Microscope Facility at the Institute of Neurobiology, COBRE Phase 2: Center for Neuroplasticity at the University of Puerto Rico, Center for Collaborative Research in Health Disparities, G8697520934, Encoding Long Term Stability of Neuronal Function, G9000043731, G9000074285, G9000137974
OpenAlex ID: W1971265527