title: Improved detection of electrical activity with a voltage probe based on a voltage-sensing phosphatase.
abstract: One of the most awaited techniques in modern physiology is the sensitive detection of spatiotemporal electrical activity in a complex network of excitable cells. The use of genetically encoded voltage probes has been expected to enable such analysis. However, in spite of recent progress, existing probes still suffer from low signal amplitude and/or kinetics too slow to detect fast electrical activity. Here, we have developed an improved voltage probe named Mermaid2, which is based on the voltage-sensor domain of the voltage-sensing phosphatase from Ciona intestinalis and Förster energy transfer between a pair of fluorescent proteins. In mammalian cells, Mermaid2 permits ratiometric readouts of fractional changes of more than 50% over a physiologically relevant voltage range with fast kinetics, and it was used to follow a train of action potentials at frequencies of up to 150 Hz. Mermaid2 was also able to detect single action potentials and subthreshold voltage responses in hippocampal neurons in vitro, in addition to cortical electrical activity evoked by sound stimuli in single trials in living mice.
authors.affiliation: H. Tsutsui: Osaka University, Yamadaoka 2-2, Suita 565-0871, Japan. tsutsui@phys2.med.osaka-u.ac.jp.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Tsutsui
authors.forename: Yuka
authors.initials: Y
authors.lastname: Jinno
authors.forename: Akiko
authors.initials: A
authors.lastname: Tomita
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Niino
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Yamada
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Mikoshiba
authors.forename: Atsushi
authors.initials: A
authors.lastname: Miyawaki
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okamura
mesh_terms: D000200:Action Potentials; D000818:Animals; D031541:Fluorescence Resonance Energy Transfer; D059907:Functional Neuroimaging / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D009474:Neurons / Q000502:physiology; D062308:Optogenetics / Q000379:methods*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D014981:Xenopus
chemical_list: D049452:Green Fluorescent Proteins; C509671:voltage-sensor-containing phosphatase, Ciona intestinalis; D010744:Phosphoric Monoester Hydrolases