title: Synapsin is required to "boost" memory strength for highly salient events.
abstract: Synapsin is an evolutionarily conserved presynaptic phosphoprotein. It is encoded by only one gene in the Drosophila genome and is expressed throughout the nervous system. It regulates the balance between reserve and releasable vesicles, is required to maintain transmission upon heavy demand, and is essential for proper memory function at the behavioral level. Task-relevant sensorimotor functions, however, remain intact in the absence of Synapsin. Using an odor-sugar reward associative learning paradigm in larval Drosophila, we show that memory scores in mutants lacking Synapsin (syn(97)) are lower than in wild-type animals only when more salient, higher concentrations of odor or of the sugar reward are used. Furthermore, we show that Synapsin is selectively required for larval short-term memory. Thus, without Synapsin Drosophila larvae can learn and remember, but Synapsin is required to form memories that match in strength to event salience-in particular to a high saliency of odors, of rewards, or the salient recency of an event. We further show that the residual memory scores upon a lack of Synapsin are not further decreased by an additional lack of the Sap47 protein. In combination with mass spectrometry data showing an up-regulated phosphorylation of Synapsin in the larval nervous system upon a lack of Sap47, this is suggestive of a functional interdependence of Synapsin and Sap47.
authors.affiliation: Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Kleber
authors.affiliation: Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany.
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Michels
authors.affiliation: Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany.
authors.forename: Timo
authors.initials: T
authors.lastname: Saumweber
authors.affiliation: Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schleyer
authors.affiliation: Otto von Guericke Universität Magdeburg, Institut für Experimentelle Innere Medizin, 39120 Magdeburg, Germany.
authors.forename: Thilo
authors.initials: T
authors.lastname: Kähne
authors.affiliation: Institut für Klinische Neurobiologie, 97078 Würzburg, Germany.
authors.forename: Erich
authors.initials: E
authors.lastname: Buchner
authors.affiliation: Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany Otto von Guericke Universität Magdeburg, Institut für Biologie, 39106 Magdeburg, Germany bertram.gerber@lin-magdeburg.de.
authors.forename: Bertram
authors.initials: B
authors.lastname: Gerber
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001245:Association Learning; D002853:Chromatography, Liquid; D004195:Disease Models, Animal; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D007814:Larva; D013058:Mass Spectrometry; D008568:Memory / Q000502:physiology*; D008569:Memory Disorders / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009812:Odorants; D010766:Phosphorylation / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D016704:Synapsins / Q000235:genetics / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C097026:Sap47 protein, Drosophila; D016704:Synapsins