Temporally precise labeling and control of neuromodulatory circuits in the mammalian brain.
                            
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                                CRY2/CIB1
                            
                                iLID
                            
                            
                                
                                    HEK293T
                                
                            
                                
                                    mouse in vivo
                                
                            
                                
                                    primary rat hippocampal neurons
                                
                            
                            
                                Transgene expression
                            
                                Neuronal activity control
                            
                            
                            
                            
                            
                        
                        
                        
                        
                            Abstract:
                            Few tools exist to visualize and manipulate neurons that are targets of neuromodulators. We present iTango, a light- and ligand-gated gene expression system based on a light-inducible split tobacco etch virus protease. Cells expressing the iTango system exhibit increased expression of a marker gene in the presence of dopamine and blue-light exposure, both in vitro and in vivo. We demonstrated the iTango system in a behaviorally relevant context, by inducing expression of optogenetic tools in neurons under dopaminergic control during a behavior of interest. We thereby gained optogenetic control of these behaviorally relevant neurons. We applied the iTango system to decipher the roles of two classes of dopaminergic neurons in the mouse nucleus accumbens in a sensitized locomotor response to cocaine. Thus, the iTango platform allows for control of neuromodulatory circuits in a genetically and functionally defined manner with spatial and temporal precision.