High-Performance Genetically Targetable Optical Neural Silencing via Light-Driven Proton Pumps

The ability to silence the activity of genetically specified neurons in a temporally precise fashion would open up the ability to investigate the causal role of specific cell classes in neural computations, behaviors, and pathologies. Here we show that members of the class of light-driven outward proton pumps can mediate very powerful, safe, multiple-color silencing of neural activity. The gene archaerhodopsin-31 (Arch) from Halorubrum sodomense enables near-100% silencing of neurons in the awake brain when virally expressed in mouse cortex and illuminated with yellow light. Arch mediates currents of several hundred picoamps at low light powers, and supports neural silencing currents approaching 900 pA at light powers easily achievable in vivo. In addition, Arch spontaneously recovers from light-dependent inactivation, unlike light-driven chloride pumps that enter long-lasting inactive states in response to light. These properties of Arch are appropriate to mediate the optical silencing of significant brain volumes over behaviourallyrelevant timescales. Arch function in neurons is well tolerated because pH excursions created by Arch illumination are minimized by self-limiting mechanisms to levels comparable to those mediated by channelrhodopsins2,3 or natural spike firing. To highlight how proton pump ecological and genomic diversity may support new innovation, we show that the blue-green lightdrivable proton pump from the fungus Leptosphaeria maculans4 (Mac) can, when expressed in neurons, enable neural silencing by blue light, thus enabling alongside other developed reagents Users may view, print, copy, download and text and datamine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: http://www.nature. com/authors/editorial_policies/license.html#terms Correspondence and requests for materials should be addressed to E.S. B. (esb@media.mit.edu). Authors' Contributions B.Y. C. , X.H. , and E.S. B. designed experiments, analyzed data, and wrote the paper. B.Y. C. and X.H. carried out experiments. A.S. D. assisted with electrophysiological recording. X.Q. , M.L. , and A.S. C. assisted with molecular biology, virus making, and transfections. M.A.H. performed Monte Carlo modelling. P.E. M. , G.M. B. , and Y.L. created hippocampal and cortical neural cultures. (†)These authors contributed equally to this work. Supplementary Information accompanies the paper on www.nature. com/nature GENBANK (http://www.ncbi.nlm.nih.gov/) accession numbers: mammalian codon-optimized Arch, GU045593; mammalian codonoptimized Arch fused to GFP, GU045594; mammalian codon-optimized Mac, GU045595; mammalian codon-optimized Mac fused to GFP, GU045596; ss-Prl-Arch, GU045597; ss-Arch-GFP-ER2, GU045598; ss-Prl-Arch-GFP, GU045599. Reprints and permissions information is available at npg.nature. com/reprintsandpermissions The authors declare no competing financial interests. HHS Public Access Author manuscript Nature. Author manuscript; available in PMC 2010 September 15. Published in final edited form as: Nature. 2010 January 7; 463(7277): 98–102. doi:10.1038/nature08652. A uhor M anscript