Abstract: Kerem YILDIRIM

The SLC5A like protein Rumpel is required in glial cells for normal neuronal network function

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Kerem Y?ld?r?m, Silke Thomas, Stefanie Mackensen, Benamin Risse Nils Otto, Christian Klämbt

Institute of Neurobiology, University of Münster

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Glial cells not only provide trophic support and guidance cues for neurons but also regulate neuronal excitability by recycling neurotransmitters from the synaptic cleft. However, we still don’t know how exactly glial genes modulate neuronal network functions. Therefore, we performed a large scale RNAi screen to identify glial genes that are regulating these functions using locomotion abilities as readout. Further glial subtype specific gene silencing experiments led to identification of six genes required in the wrapping or ensheathing glia. In order to quantify the locomotion phenotypes we developed a novel imaging method based on frustrated total internal reflection, FIM. It allows the recording of many crawling third instar larvae at very high resolution and simultaneously provides the possibility to include external stimuli.
Glial knockdown of rumpel did not severely affect larval locomotion at room temperature. However, when larvae are placed in a heat gradient 32°C they are paralyzed, whereas wild type larvae move towards cooler temperatures. Likewise, adults with a glial-specific rumpel knockdown paralyze when exposed to elevated temperatures (38°C), whereas wild type flies recover instantly. The temperature dependent paralysis upon rumpel knockdown can be rescued by the expression of a rumpel cDNA. rumpel encodes a sodium/solute transporter with homology to monocarboxylate transporters of the SLC5A family, suggesting that rumpel may function during glial energy homeostasis. We are currently performing interspecies rescue experiments with biochemically described SLC5A transporters to delineate the cargo transported by Rumpel.