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Main Menu - Block
- Overview
 - Anatomy and Histology
 - Cryo-Electron Microscopy
 - Electron Microscopy
 - Flow Cytometry
 - Gene Targeting and Transgenics
 - High Performance Computing
 - Immortalized Cell Line Culture
 - Integrative Imaging
 - Invertebrate Shared Resource
 - Janelia Experimental Technology
 - Mass Spectrometry
 - Media Prep
 - Molecular Genomics
 - Primary & iPS Cell Culture
 - Project Pipeline Support
 - Project Technical Resources
 - Quantitative Genomics
 - Scientific Computing
 - Viral Tools
 - Vivarium
 
Abstract
Targeted manipulation of activity in specific populations of neurons is important for investigating the neural circuit basis of behavior. Optogenetic approaches using light-sensitive microbial rhodopsins have permitted manipulations to reach a level of temporal precision that is enabling functional circuit dissection. As demand for more precise perturbations to serve specific experimental goals increases, a palette of opsins with diverse selectivity, kinetics, and spectral properties will be needed. Here, we introduce a novel approach of "topological engineering"-inversion of opsins in the plasma membrane-and demonstrate that it can produce variants with unique functional properties of interest for circuit neuroscience. In one striking example, inversion of a Channelrhodopsin variant converted it from a potent activator into a fast-acting inhibitor that operates as a cation pump. Our findings argue that membrane topology provides a useful orthogonal dimension of protein engineering that immediately permits as much as a doubling of the available toolkit.








