@article {6890, title = {Cell-type-specific labeling of synapses in vivo through synaptic tagging with recombination.}, journal = {Neuron}, volume = {81}, year = {2014}, month = {2014 Jan 22}, pages = {280-93}, abstract = {

The study of synaptic specificity and plasticity in the CNS is limited by the inability to efficiently visualize synapses in identified neurons using light microscopy. Here, we describe synaptic tagging with recombination (STaR), a method for labeling endogenous presynaptic and postsynaptic proteins in a cell-type-specific fashion. We modified genomic loci encoding synaptic proteins within bacterial artificial chromosomes such that these proteins, expressed at endogenous levels and with normal spatiotemporal patterns, were labeled in an inducible fashion in specific neurons through targeted expression of site-specific recombinases. Within the Drosophila visual system, the number and distribution of synapses correlate with electron microscopy studies. Using two different recombination systems, presynaptic and postsynaptic specializations of synaptic pairs can be colabeled. STaR also allows synapses within the CNS to be studied in live animals noninvasively. In principle, STaR can be adapted to the mammalian nervous system.

}, keywords = {Animals, Drosophila, Drosophila Proteins, Electron, Genetic, Genetically Modified, Luminescent Proteins, Medulla Oblongata, Microscopy, Nerve Tissue Proteins, Neurons, Neurotransmitter, Presynaptic Terminals, Receptors, Recombinases, Recombination, Synapses, Transcription Factors, Transmission, Visual Pathways}, issn = {1097-4199}, doi = {10.1016/j.neuron.2013.12.021}, author = {Chen, Yi and Akin, Orkun and Nern, Aljoscha and Tsui, C Y Kimberly and Pecot, Matthew Y and Zipursky, S Lawrence} } @article {6923, title = {Genetic and neural mechanisms that inhibit Drosophila from mating with other species.}, journal = {Cell}, volume = {154}, year = {2013}, month = {2013 Jul 3}, pages = {89-102}, abstract = {

Genetically hard-wired neural mechanisms must enforce behavioral reproductive isolation because interspecies courtship is rare even in sexually na{\"{\i}ve animals of most species. We find that the chemoreceptor Gr32a inhibits male D. melanogaster from courting diverse fruit fly species. Gr32a recognizes nonvolatile aversive cues present on these reproductively dead-end targets, and activity of Gr32a neurons is necessary and sufficient to inhibit interspecies courtship. Male-specific Fruitless (Fru(M)), a master regulator of courtship, also inhibits interspecies courtship. Gr32a and Fru(M) are not coexpressed, but Fru(M) neurons contact Gr32a neurons, suggesting that these genes influence a shared neural circuit that inhibits interspecies courtship. Gr32a and Fru(M) also suppress within-species intermale courtship, but we show that distinct mechanisms preclude sexual displays toward conspecific males and other species. Although this chemosensory pathway does not inhibit interspecies mating in D. melanogaster females, similar mechanisms appear to inhibit this behavior in many other male drosophilids.

}, keywords = {Animal, Animals, Cell Surface, Courtship, Drosophila, Drosophila melanogaster, Drosophila Proteins, Female, Genetic Speciation, Male, Mating Preference, Nerve Tissue Proteins, Neurons, Receptors, Transcription Factors}, issn = {1097-4172}, doi = {10.1016/j.cell.2013.06.008}, author = {Fan, Pu and Manoli, Devanand S and Ahmed, Osama M and Chen, Yi and Agarwal, Neha and Kwong, Sara and Cai, Allen G and Neitz, Jeffrey and Renslo, Adam and Baker, Bruce S and Shah, Nirao M} } @article {6926, title = {Multiple interactions control synaptic layer specificity in the Drosophila visual system.}, journal = {Neuron}, volume = {77}, year = {2013}, month = {2013 Jan 23}, pages = {299-310}, abstract = {

How neurons form synapses within specific layers remains poorly understood. In the Drosophila medulla, neurons target to discrete layers in a precise fashion. Here we demonstrate that the targeting of L3 neurons to a specific layer occurs in two steps. Initially, L3 growth cones project to a common domain in the outer medulla, overlapping with the growth cones of other neurons destined for a different layer through the redundant functions of N-Cadherin (CadN) and Semaphorin-1a (Sema-1a). CadN mediates adhesion within the domain and Sema-1a mediates repulsion through Plexin A (PlexA) expressed in an adjacent region. Subsequently, L3 growth cones segregate from the domain into their target layer in part through Sema-1a/PlexA-dependent remodeling. Together, our results and recent studies argue that the early medulla is organized into common domains, comprising processes bound for different layers, and that discrete layers later emerge through successive interactions between processes within domains and developing layers.

}, keywords = {Animals, Cell Communication, Drosophila, Drosophila Proteins, Genetically Modified, Growth Cones, Medulla Oblongata, Protein Interaction Mapping, Synapses, Visual Pathways}, issn = {1097-4199}, doi = {10.1016/j.neuron.2012.11.007}, author = {Pecot, Matthew Y and Tadros, Wael and Nern, Aljoscha and Bader, Maya and Chen, Yi and Zipursky, S Lawrence} }