Although many synaptic molecules have been identified, the processes and factors that lead to the development of a mature synapse have remained largely unknown. The present proposal seeks to examine the molecular mechanisms involved in the maturation of synapses by using an attractive model system, the Drosophila neuromuscular junction. Through the analysis of mutants in which synaptic structure is disrupted, we expect to identify genes involved in its assembly and maturation. We propose to examine the differentiation of functional neuromuscular contacts using a combination of whole cell patch recordings and ultrastructural techniques. This analysis will be performed in wild type and in two mutants that alter synaptic structure. One such mutation defines the tumor suppressor gene lethal(1) discs large (dlg), whose products belong to a family of proteins present at cell junctions in both vertebrates and invertebrates, including the fly neuromuscular junction, and mammalian brain synapses. The other mutant is branch point disrupted (bpd), which was isolated in a direct screen for mutants altering synapse structure. The functional correlates of the structural defects in these mutants will be examined by electrophysiological techniques, including voltage clamp recordings of whole muscle fibers and macropatch recordings of single synaptic boutons. In addition, we will determine the contribution of the dlg locus in determining synaptic structure by targeting dlg expression to pre and postsynaptic sites, as well as to both appropriate and inappropriate motorneurons. An ongoing genetic screen, using P[Gal4]-element mutagenesis will be conducted, in a search for other mutants altering neuromuscularjunction development. This mutagenesis scheme is based on the stereotypic innervation of larval neuromuscular junctions by identified motor axons.We expect that the outcome of these studies will be relevant to neuromuscular junctions in both vertebrates and invertebrates, and to synapses in general. A better understanding of the molecular basis of the development of synapses will provide much needed insight into a host of neuromuscular and central nervous system disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS030072-07
Application #
2635717
Study Section
Neurology C Study Section (NEUC)
Program Officer
Nichols, Paul L
Project Start
1992-01-01
Project End
1998-12-31
Budget Start
1998-01-01
Budget End
1998-12-31
Support Year
7
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Massachusetts Amherst
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
153223151
City
Amherst
State
MA
Country
United States
Zip Code
01003
Ramachandran, Preethi; Barria, Romina; Ashley, James et al. (2009) A critical step for postsynaptic F-actin organization: regulation of Baz/Par-3 localization by aPKC and PTEN. Dev Neurobiol 69:583-602
Chai, Andrea; Withers, James; Koh, Young Ho et al. (2008) hVAPB, the causative gene of a heterogeneous group of motor neuron diseases in humans, is functionally interchangeable with its Drosophila homologue DVAP-33A at the neuromuscular junction. Hum Mol Genet 17:266-80
Griffith, Leslie C; Budnik, Vivian (2006) Plasticity and second messengers during synapse development. Int Rev Neurobiol 75:237-65
Ruiz-Canada, Catalina; Budnik, Vivian (2006) Introduction on the use of the Drosophila embryonic/larval neuromuscular junction as a model system to study synapse development and function, and a brief summary of pathfinding and target recognition. Int Rev Neurobiol 75:1-31
Ruiz-Canada, Catalina; Budnik, Vivian (2006) Synaptic cytoskeleton at the neuromuscular junction. Int Rev Neurobiol 75:217-36
Mathew, Dennis; Popescu, Andrei; Budnik, Vivian (2003) Drosophila amphiphysin functions during synaptic Fasciclin II membrane cycling. J Neurosci 23:10710-6
Packard, Mary; Mathew, Dennis; Budnik, Vivian (2003) FASt remodeling of synapses in Drosophila. Curr Opin Neurobiol 13:527-34
Koh, Young-Ho; Ruiz-Canada, Catalina; Gorczyca, Michael et al. (2002) The Ras1-mitogen-activated protein kinase signal transduction pathway regulates synaptic plasticity through fasciclin II-mediated cell adhesion. J Neurosci 22:2496-504
Park, Demian; Coleman, Melissa J; Hodge, James J L et al. (2002) Regulation of neuronal excitability in Drosophila by constitutively active CaMKII. J Neurobiol 52:24-42
Thomas, U; Ebitsch, S; Gorczyca, M et al. (2000) Synaptic targeting and localization of discs-large is a stepwise process controlled by different domains of the protein. Curr Biol 10:1108-17

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