Richard Fetter

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We conducted a large-scale screen for Drosophila mutants that have structural abnormalities of the larval neuromuscular junction (NMJ). We recovered mutations in wishful thinking (wit), a gene that positively regulates synaptic growth. wit encodes a BMP type II receptor. In wit mutant larvae, the size of the NMJs is greatly reduced relative to the size of(More)
Most neurons form synapses exclusively with other neurons, but little is known about the molecular mechanisms mediating synaptogenesis in the central nervous system. Using an in vitro system, we demonstrate that neuroligin-1 and -2, postsynaptically localized proteins, can trigger the de novo formation of presynaptic structure. Nonneuronal cells engineered(More)
Postsynaptic sensitivity to glutamate was genetically manipulated at the Drosophila neuromuscular junction (NMJ) to test whether postsynaptic activity can regulate presynaptic function during development. We cloned the gene encoding a second muscle-specific glutamate receptor, DGluRIIB, which is closely related to the previously identified DGluRIIA and(More)
The robo gene in Drosophila was identified in a large-scale mutant screen for genes that control the decision by axons to cross the CNS midline. In robo mutants, too many axons cross and recross the midline. Here we show that robo encodes an axon guidance receptor that defines a novel subfamily of immunoglobulin superfamily proteins that is highly conserved(More)
We show that the BMP ortholog Gbb can signal by a retrograde mechanism to regulate synapse growth of the Drosophila neuromuscular junction (NMJ). gbb mutants have a reduced NMJ synapse size, decreased neurotransmitter release, and aberrant presynaptic ultrastructure. These defects are similar to those we observe in mutants of BMP receptors and Smad(More)
Increased neuronal activity (eag Shaker mutants) and cAMP concentration (dunce mutants) lead to increased synaptic structure and function at the Drosophila neuromuscular junction. Here, we show that the increase in synaptic growth is accompanied by an approximately 50% decrease in synaptic levels of the cell adhesion molecule Fasciclin II (Fas II). This(More)
The glutamatergic neuromuscular synapse in Drosophila forms and differentiates into distinct boutons in the embryo and grows by sprouting new boutons throughout larval life. We demonstrate that two axons form approximately 18 boutons on muscles 7 and 6 by hatching and grow to approximately 180 boutons by third instar. We further show that, after synapse(More)
Mutations in dpix were recovered from a large-scale screen in Drosophila for genes that control synaptic structure. dpix encodes dPix, a Rho-type guanine nucleotide exchange factor (RtGEF) homologous to mammalian Pix. Here we show that dPix plays a major role in regulating postsynaptic structure and protein localization at the Drosophila glutamatergic(More)
The formation, stabilization, and growth of synaptic connections are dynamic and highly regulated processes. The glutamatergic neuromuscular junction (NMJ) in Drosophila grows new boutons and branches throughout larval development. A primary walking behavior screen followed by a secondary anatomical screen led to the identification of the highwire (hiw)(More)
The identification of synaptic partners is challenging in dense nerve bundles, where many processes occupy regions beneath the resolution of conventional light microscopy. To address this difficulty, we have developed GRASP, a system to label membrane contacts and synapses between two cells in living animals. Two complementary fragments of GFP are expressed(More)