title: A genetically encoded optical probe of membrane voltage.
abstract: Measuring electrical activity in large numbers of cells with high spatial and temporal resolution is a fundamental problem for the study of neural development and information processing. To address this problem, we have constructed a novel, genetically encoded probe that can be used to measure transmembrane voltage in single cells. We fused a modified green fluorescent protein (GFP) into a voltage-sensitive K+ channel so that voltage-dependent rearrangements in the K+ channel would induce changes in the fluorescence of GFP. The probe has a maximal fractional fluorescence change of 5.1%, making it comparable to some of the best organic voltage-sensitive dyes. Moreover, the fluorescent signal is expanded in time in a way that makes the signal 30-fold easier to detect. A voltage sensor encoded into DNA has the advantage that it may be introduced into an organism noninvasively and targeted to specific developmental stages, brain regions, cell types, and subcellular compartments.
authors.affiliation: University of California, Department of Molecular and Cell Biology, Berkeley 94720, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Siegel
authors.forename: E Y
authors.initials: EY
authors.lastname: Isacoff
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000502:physiology*; D049452:Green Fluorescent Proteins; D007700:Kinetics; D008164:Luminescent Proteins / Q000032:analysis / Q000096:biosynthesis / Q000737:chemistry; D008564:Membrane Potentials; D008961:Models, Structural; D009474:Neurons / Q000502:physiology*; D009865:Oocytes / Q000502:physiology; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology*; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D051637:Shaker Superfamily of Potassium Channels; D014981:Xenopus
chemical_list: D008164:Luminescent Proteins; D015221:Potassium Channels; D011993:Recombinant Fusion Proteins; D051637:Shaker Superfamily of Potassium Channels; D049452:Green Fluorescent Proteins