# Transgenic Strategy for Identifying Synaptic Connections in Mice by Fluorescence Complementation (GRASP)

 Title: Transgenic Strategy for Identifying Synaptic Connections in Mice by Fluorescence Complementation (GRASP) Author: Yamagata, Masahito; Sanes, Joshua R. Note: Order does not necessarily reflect citation order of authors. Citation: Yamagata, Masahito, and Joshua R. Sanes. 2012. Transgenic strategy for identifying synaptic connections in mice by fluorescence complementation (GRASP). Frontiers in Molecular Neuroscience 5: 18. Full Text & Related Files: 3280602.pdf (1.719Mb; PDF) Abstract: In the “GFP reconstitution across synaptic partners” (GRASP) method, non-fluorescent fragments of GFP are expressed in two different neurons; the fragments self-assemble at synapses between the two to form a fluorophore. GRASP has proven useful for light microscopic identification of synapses in two invertebrate species, $$Caenorhabditis$$ $$elegans$$ and $$Drosophila$$ $$melanogaster$$, but has not yet been applied to vertebrates. Here, we describe GRASP constructs that function in mammalian cells and implement a transgenic strategy in which a Cre-dependent gene switch leads to expression of the two fragments in mutually exclusive neuronal subsets in mice. Using a transgenic line that expresses Cre selectively in rod photoreceptors, we demonstrate labeling of synapses in the outer plexiform layer of the retina. Labeling is specific, in that synapses made by rods remain labeled for at least 6 months whereas nearby synapses made by intercalated cone photoreceptors on many of the same interneurons remain unlabeled. We also generated antisera that label reconstituted GFP but neither fragment in order to amplify the GRASP signal and thereby increase the sensitivity of the method. Published Version: doi:10.3389/fnmol.2012.00018 Other Sources: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3280602/pdf/ Terms of Use: This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAA Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:8497447

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Peer reviewed scholarly articles from the Faculty of Arts and Sciences of Harvard University