title: Flies lacking all synapsins are unexpectedly healthy but are impaired in complex behaviour.
abstract: Vertebrate synapsins are abundant synaptic vesicle phosphoproteins that have been proposed to fine-regulate neurotransmitter release by phosphorylation-dependent control of synaptic vesicle motility. However, the consequences of a total lack of all synapsin isoforms due to a knock-out of all three mouse synapsin genes have not yet been investigated. In Drosophila a single synapsin gene encodes several isoforms and is expressed in most synaptic terminals. Thus the targeted deletion of the synapsin gene of Drosophila eliminates the possibility of functional knock-out complementation by other isoforms. Unexpectedly, synapsin null mutant flies show no obvious defects in brain morphology, and no striking qualitative changes in behaviour are observed. Ultrastructural analysis of an identified 'model' synapse of the larval nerve muscle preparation revealed no difference between wild-type and mutant, and spontaneous or evoked excitatory junction potentials at this synapse were normal up to a stimulus frequency of 5 Hz. However, when several behavioural responses were analysed quantitatively, specific differences between mutant and wild-type flies are noted. Adult locomotor activity, optomotor responses at high pattern velocities, wing beat frequency, and visual pattern preference are modified. Synapsin mutant flies show faster habituation of an olfactory jump response, enhanced ethanol tolerance, and significant defects in learning and memory as measured using three different paradigms. Larval behavioural defects are described in a separate paper. We conclude that Drosophila synapsins play a significant role in nervous system function, which is subtle at the cellular level but manifests itself in complex behaviour.
authors.affiliation: Theodor Boveri-Institut für Biowissenschaften, Lehrstuhl für Genetik und Neurobiologie, Am Hubland D-97074 Wuerzburg, Germany.
authors.forename: Tanja A
authors.initials: TA
authors.lastname: Godenschwege
authors.forename: Dietmar
authors.initials: D
authors.lastname: Reisch
authors.forename: Sören
authors.initials: S
authors.lastname: Diegelmann
authors.forename: Kai
authors.initials: K
authors.lastname: Eberle
authors.forename: Natalja
authors.initials: N
authors.lastname: Funk
authors.forename: Martin
authors.initials: M
authors.lastname: Heisenberg
authors.forename: Viviane
authors.initials: V
authors.lastname: Hoppe
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hoppe
authors.forename: Bert R E
authors.initials: BR
authors.lastname: Klagges
authors.forename: Jean-René
authors.initials: JR
authors.lastname: Martin
authors.forename: Ekaterina A
authors.initials: EA
authors.lastname: Nikitina
authors.forename: Gabi
authors.initials: G
authors.lastname: Putz
authors.forename: Rita
authors.initials: R
authors.lastname: Reifegerste
authors.forename: Natascha
authors.initials: N
authors.lastname: Reisch
authors.forename: Jens
authors.initials: J
authors.lastname: Rister
authors.forename: Michael
authors.initials: M
authors.lastname: Schaupp
authors.forename: Henrike
authors.initials: H
authors.lastname: Scholz
authors.forename: Martin
authors.initials: M
authors.lastname: Schwärzel
authors.forename: Ursula
authors.initials: U
authors.lastname: Werner
authors.forename: Troy D
authors.initials: TD
authors.lastname: Zars
authors.forename: Sigrid
authors.initials: S
authors.lastname: Buchner
authors.forename: Erich
authors.initials: E
authors.lastname: Buchner
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D000818:Animals; D030801:Animals, Genetically Modified; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D015153:Blotting, Western / Q000379:methods; D002492:Central Nervous System Depressants / Q000494:pharmacology; D003001:Cloning, Molecular / Q000379:methods; D003216:Conditioning, Operant / Q000502:physiology; D004252:DNA Mutational Analysis; D004330:Drosophila / Q000235:genetics / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D000431:Ethanol / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000235:genetics; D007150:Immunohistochemistry / Q000379:methods; D007163:Immunosorbent Techniques; D008564:Membrane Potentials / Q000235:genetics / Q000502:physiology; D008854:Microscopy, Electron; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D016296:Mutagenesis / Q000502:physiology; D009469:Neuromuscular Junction / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D012725:Sexual Behavior / Q000187:drug effects / Q000502:physiology; D013569:Synapses / Q000378:metabolism / Q000648:ultrastructure; D016704:Synapsins / Q000172:deficiency* / Q000235:genetics / Q000502:physiology; D013572:Synaptic Vesicles / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D013997:Time Factors; D014018:Tissue Distribution; D014796:Visual Perception / Q000235:genetics / Q000502:physiology; D016138:Walking / Q000502:physiology; D014921:Wings, Animal / Q000502:physiology
chemical_list: D002492:Central Nervous System Depressants; D016704:Synapsins; D000431:Ethanol