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.
Subject(s)
Brain/metabolism , Dopamine/metabolism , Gene Expression , Light , Neural Pathways/physiology , Optogenetics/methods , Animals , Behavior, Animal/physiology , Brain/cytology , Brain Mapping/methods , Dopamine/pharmacology , Endopeptidases/genetics , Gene Expression/drug effects , Gene Expression/radiation effects , HEK293 Cells , Humans , Ligands , Mice , Neurons/metabolism , Photic Stimulation , Rats , Receptors, Dopamine D2/genetics , Signal-To-Noise RatioABSTRACT
The optimization, based on computational, thermodynamic, and crystallographic data, of a series of small-molecule ligands of the Phe43 cavity of the envelope glycoprotein gp120 of human immunodeficiency virus (HIV) has been achieved. Importantly, biological evaluation revealed that the small-molecule CD4 mimics (4-7) inhibit HIV-1 entry into target cells with both significantly higher potency and neutralization breadth than previous congeners, while maintaining high selectivity for the target virus. Their binding mode was characterized via thermodynamic and crystallographic studies.
