Journal: PloS one

Article Title: A fluorescent, genetically-encoded voltage probe capable of resolving action potentials.

doi: 10.1371/journal.pone.0043454

Figure Lengend Snippet: Figure 4. Examples of CiVSP::cpEGFP constructs expression in HEK293 cells and voltage sensitivity. In all cases the upper panel is a confocal image of HEK293 cells transiently expressing the construct and the lower panel is the average fluorescence response (red trace) to ten +100 mV/200 ms voltage steps applied under whole-cell patch clamp configuration. Correction for FP photobleaching has been removed by division of a double exponential fit to the portions of the trace outside the effects of the voltage step. A) The ElectricPk (pLB 2.7) probe is localized both in the membrane and intracellularly. The probe exhibits a rapid decrease in fluorescence with a relatively low signal to noise ratio due to relatively weak basal fluorescence. B) The high expression levels of construct pLB7.7 produces a relatively high signal to noise ratio, however much of the fluorescent protein is localized intracellularly, and its fluorescence response is dominated by a slow component. C) Construct pLB1.8 has mixed membrane and intracellular distribution that produces a small and rapid negative response with a moderate signal to noise ratio. D) pLB10.8 has predominantly intracellular localization and a small positive fluores- cence response with a moderate signal to noise ratio. doi:10.1371/journal.pone.0043454.g004

Article Snippet: ElectricPK is available at Addgene or at the site www.fluorogenetic-voltagesensors.org.

Techniques: Construct, Expressing, Fluorescence, Patch Clamp, Membrane

Journal: PloS one

Article Title: A fluorescent, genetically-encoded voltage probe capable of resolving action potentials.

doi: 10.1371/journal.pone.0043454

Figure Lengend Snippet: Figure 5. Voltage sensitivity and response kinetics of Elec- tricPk. A) Voltage-dependent fluorescence sensitivity of an HEK293 cell when transiently expressing ElectricPK (red trace) verses mUKG in Mermaid (upper black trace) tested with voltage steps of +100 mV/ 200 ms from a 270 mV holding potential (lower black trace). Fluorescence, in all cases, is normalized to initial and peak level. B) Single exponential fits to the dominant on and off response rates of ElectricPk and mUKG of Mermaid in cells tested as in A. C) and D) Response of HEK 293 cell expressing ElectricPk (red trace) to a trains of voltage steps of +100 mV from a 270 mV holding potential with a variable duration; 100 ms, 3 ms and 1 ms (black trace). doi:10.1371/journal.pone.0043454.g005

Article Snippet: ElectricPK is available at Addgene or at the site www.fluorogenetic-voltagesensors.org.

Techniques: Fluorescence, Expressing

Journal: PloS one

Article Title: A fluorescent, genetically-encoded voltage probe capable of resolving action potentials.

doi: 10.1371/journal.pone.0043454

Figure Lengend Snippet: Figure 6. Linear DF/DV response of ElectricPK. A) Fluorescence response (upper traces) of HEK293 cells transiently expressing ElectricPk to depolarizing and hyperpolarizing voltage steps (2170 to +30 mV from a 270 mV holding potential, lower traces). B) DF/DV curve of ElectricPk derived from data presented in A. doi:10.1371/journal.pone.0043454.g006

Article Snippet: ElectricPK is available at Addgene or at the site www.fluorogenetic-voltagesensors.org.

Techniques: Fluorescence, Expressing, Derivative Assay

Journal: PloS one

Article Title: A fluorescent, genetically-encoded voltage probe capable of resolving action potentials.

doi: 10.1371/journal.pone.0043454

Figure Lengend Snippet: Figure 7. Detection of action potentials in hippocampal neurons in vitro using ElectricPK. A) Wide field image of an in vitro hippocampal neuron expressing ElectricPk. Bar = 15 mm. B) Single (light red trace) and averaged (red trace) optical response to action potentials evoked in the neuron seen in (A) taken using wide field microscopy and a RedShirtImaging NeuroCCD camera. The red trace is an average of 32 action potentials. All responses captured at 2000 fps. C) Fluorescence change (light red trace-unfiltered, red trace-filtered) to a single train of evoked action potentials recorded from an in vitro hippocampal neuron expressing ElectricPk. Lower black trace is the voltage recording made from the patch electrode. All fluorescence traces are bleach subtracted and where indicated, low pass filtered (Bessel) at 350 Hz. doi:10.1371/journal.pone.0043454.g007

Article Snippet: ElectricPK is available at Addgene or at the site www.fluorogenetic-voltagesensors.org.

Techniques: In Vitro, Expressing, Microscopy, Fluorescence