Neurons in the retina make remarkably precise connections with their synaptic targets. Indeed, such precision is a hallmark of neuronal connectivity in many parts of the brain. These synaptic patterns define the wiring diagram of the nervous system and determine, in part, how the brain computes. Many of these connections are genetically programmed to form in the absence of sensory input. However, the molecular mechanisms that underlie how the genome encodes information about these patterns of connections and applies this information to specify the targets of each individual neuron are poorly understood. The visual system of Drosophila presents a unique opportunity to use genetic techniques to determine how such mechanisms can control neuronal target selection. Photoreceptor cells, for example, make synaptic connections with a spatially invariant group of post-synaptic partners, and can do so in the absence of visual input. How can such a precise set of connections be genetically hard-wired? The proposed experiments examine these mechanisms in the context of one particular group of neuronal cell adhesion molecules, the cadherins. These proteins are thought to play critical roles in controlling synapse formation. How do classical cadherins influence synaptic partner choice? (Aim 1) How are the functions of classical cadherins regulated in neurons? (Aim 2) Do other cadherins also play a role in neuronal target selection? (Aim 3) Genetic disruptions in cadherin function cause inherited forms of retinitis pigmentosa, macular degeneration and defects in brain development. However, the molecular mechanisms that underlie cadherin functions in the brain are almost entirely unknown. Understanding these functions in a facile model system may suggest novel therapeutic strategies.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
1R01EY015231-01A1
Application #
6825505
Study Section
Neurodifferentiation, Plasticity, and Regeneration Study Section (NDPR)
Program Officer
Oberdorfer, Michael
Project Start
2004-08-01
Project End
2009-07-31
Budget Start
2004-08-01
Budget End
2005-07-31
Support Year
1
Fiscal Year
2004
Total Cost
$360,000
Indirect Cost
Name
Stanford University
Department
Biology
Type
Schools of Medicine
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Schwabe, Tina; Borycz, Jolanta A; Meinertzhagen, Ian A et al. (2014) Differential adhesion determines the organization of synaptic fascicles in the Drosophila visual system. Curr Biol 24:1304-1313
Schwabe, Tina; Neuert, Helen; Clandinin, Thomas R (2013) A network of cadherin-mediated interactions polarizes growth cones to determine targeting specificity. Cell 154:351-64
Hwa, Jennifer J; Clandinin, Thomas R (2012) Apical-basal polarity proteins are required cell-type specifically to direct photoreceptor morphogenesis. Curr Biol 22:2319-24
Schwabe, Tina; Clandinin, Thomas R (2012) Axon trapping: constructing the visual system one layer at a time. Neuron 75:6-8
Gontang, Allison C; Hwa, Jennifer J; Mast, Joshua D et al. (2011) The cytoskeletal regulator Genghis khan is required for columnar target specificity in the Drosophila visual system. Development 138:4899-909
Gohl, Daryl M; Silies, Marion A; Gao, Xiaojing J et al. (2011) A versatile in vivo system for directed dissection of gene expression patterns. Nat Methods 8:231-7
Prakash, Saurabh; McLendon, Helen M; Dubreuil, Catherine I et al. (2009) Complex interactions amongst N-cadherin, DLAR, and Liprin-alpha regulate Drosophila photoreceptor axon targeting. Dev Biol 336:10-9
Clandinin, Thomas R; Feldheim, David A (2009) Making a visual map: mechanisms and molecules. Curr Opin Neurobiol 19:174-80
Chen, Pei-Ling; Clandinin, Thomas R (2008) The cadherin Flamingo mediates level-dependent interactions that guide photoreceptor target choice in Drosophila. Neuron 58:26-33
Mast, Joshua D; Tomalty, Katharine M H; Vogel, Hannes et al. (2008) Reactive oxygen species act remotely to cause synapse loss in a Drosophila model of developmental mitochondrial encephalopathy. Development 135:2669-79

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