@article {135, title = {cJun integrates calcium activity and tlx3 expression to regulate neurotransmitter specification.}, journal = {Nat Neurosci}, volume = {13}, year = {2010}, month = {2010 Aug}, pages = {944-50}, abstract = {

Neuronal differentiation is accomplished through cascades of intrinsic genetic factors initiated in neuronal progenitors by external gradients of morphogens. Activity has been thought to be important only late in development, but recent evidence suggests that activity also regulates early neuronal differentiation. Activity in post-mitotic neurons before synapse formation can regulate phenotypic specification, including neurotransmitter choice, but the mechanisms are not clear. We identified a mechanism that links endogenous calcium spike activity with an intrinsic genetic pathway to specify neurotransmitter choice in neurons in the dorsal embryonic spinal cord of Xenopus tropicalis. Early activity modulated transcription of the GABAergic/glutamatergic selection gene tlx3 through a variant cAMP response element (CRE) in its promoter. The cJun transcription factor bound to this CRE site, modulated transcription and regulated neurotransmitter phenotype via its transactivation domain. Calcium signaled through cJun N-terminal phosphorylation, which integrated activity-dependent and intrinsic neurotransmitter specification. This mechanism provides a basis for early activity to regulate genetic pathways at critical decision points, switching the phenotype of developing neurons.

}, keywords = {Animals, Base Sequence, Calcium, Calcium Signaling, Electrophoretic Mobility Shift Assay, Gene Expression, Gene Expression Regulation, Developmental, Homeodomain Proteins, Immunohistochemistry, In Situ Hybridization, Molecular Sequence Data, Neurogenesis, Neurons, Neurotransmitter Agents, Promoter Regions, Genetic, Proto-Oncogene Proteins c-jun, Response Elements, Reverse Transcriptase Polymerase Chain Reaction, Xenopus, Xenopus Proteins}, issn = {1546-1726}, doi = {10.1038/nn.2582}, author = {Marek, Kurt W and Kurtz, Lisa M and Spitzer, Nicholas C} } @article {193, title = {Targeting single neuronal networks for gene expression and cell labeling in vivo.}, journal = {Neuron}, volume = {67}, year = {2010}, month = {2010 Aug 26}, pages = {562-74}, abstract = {

To understand fine-scale structure and function of single mammalian neuronal networks, we developed and validated a strategy to genetically target and trace monosynaptic inputs to a single neuron in vitro and in vivo. The strategy independently targets a neuron and its presynaptic network for specific gene expression and fine-scale labeling, using single-cell electroporation of DNA to target infection and monosynaptic retrograde spread of a genetically modifiable rabies virus. The technique is highly reliable, with transsynaptic labeling occurring in every electroporated neuron infected by the virus. Targeting single neocortical neuronal networks in vivo, we found clusters of both spiny and aspiny neurons surrounding the electroporated neuron in each case, in addition to intricately labeled distal cortical and subcortical inputs. This technique, broadly applicable for probing and manipulating single neuronal networks with single-cell resolution in vivo, may help shed new light on fundamental mechanisms underlying circuit development and information processing by neuronal networks throughout the brain.

}, keywords = {Animals, Electroporation, Gene Expression, Genetic Vectors, Histological Techniques, In Vitro Techniques, Mice, Neocortex, Neural Pathways, Neuroanatomical Tract-Tracing Techniques, Neuronal Tract-Tracers, Neurons, Presynaptic Terminals, Pyramidal Cells, Rabies virus, Rats, Reproducibility of Results, Visual Cortex}, issn = {1097-4199}, doi = {10.1016/j.neuron.2010.08.001}, author = {Marshel, James H and Mori, Takuma and Nielsen, Kristina J and Callaway, Edward M} } @article {165, title = {The Drosophila foraging gene mediates adult plasticity and gene-environment interactions in behaviour, metabolites, and gene expression in response to food deprivation.}, journal = {PLoS Genet}, volume = {5}, year = {2009}, month = {2009 Aug}, pages = {e1000609}, abstract = {

Nutrition is known to interact with genotype in human metabolic syndromes, obesity, and diabetes, and also in Drosophila metabolism. Plasticity in metabolic responses, such as changes in body fat or blood sugar in response to changes in dietary alterations, may also be affected by genotype. Here we show that variants of the foraging (for) gene in Drosophila melanogaster affect the response to food deprivation in a large suite of adult phenotypes by measuring gene by environment interactions (GEI) in a suite of food-related traits. for affects body fat, carbohydrates, food-leaving behavior, metabolite, and gene expression levels in response to food deprivation. This results in broad patterns of metabolic, genomic, and behavioral gene by environment interactions (GEI), in part by interaction with the insulin signaling pathway. Our results show that a single gene that varies in nature can have far reaching effects on behavior and metabolism by acting through multiple other genes and pathways.

}, keywords = {Animals, Carbohydrate Metabolism, Cyclic GMP-Dependent Protein Kinases, Drosophila melanogaster, Drosophila Proteins, Ecosystem, Fats, Food Deprivation, Gene Expression, Signal Transduction}, issn = {1553-7404}, doi = {10.1371/journal.pgen.1000609}, author = {Kent, Clement F and Daskalchuk, Tim and Cook, Lisa and Sokolowski, Marla B and Greenspan, Ralph J} }