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Vega

Photostable green eFRET GEVI built by inserting mBaoJin(3M) into the first extracellular loop of Ace2 rhodopsin, with Kv2.1 and ER2 targeting motifs for long-duration one-photon voltage imaging.

Category: eFRET GEVI
Published: 2025-06-01 — bioRxiv 2025
Derived from: Cepheid1b
Response polarity: negative-going (fluorescence decreases on depolarization)
Spectrum: excitation peak 500 nm, emission peak 508 nm (Vega)
Tags: Ace opsin, mBaoJin, Green, FRET, Somatic targeting

Headline values (as shown in the GEVIBench table)

Metric	Value	Definition
Brightness (B/B_EGFP)	6.80× EGFP	Molecular brightness relative to EGFP (extinction coefficient × quantum yield, or a measured ratio). Sensors not measured against EGFP directly are placed through a chain of pairwise brightness comparisons, combined by geometric mean.
Kinetics τ_on / τ_off (ms)	1.3 / 3.7 ms	Activation / decay time constants in ms (amplitude-weighted mean τ for multi-exponential fits). The value shown averages the measurements made at physiological temperature (≥33 °C); if there are none, it is the measurement closest to 33 °C.
ΔF/F per 100 mV	-33.1%	Steady-state fluorescence change for a 100 mV depolarization step (−70 → +30 mV); the sign gives the polarity. The table shows the first listed measurement; the median across measurements (one-photon preferred) is used for sorting.
ΔF/F per mV	0.5% (estimated from the F–V curve)	Subthreshold sensitivity: fluorescence change per mV near rest (−90 to −50 mV). Where no value is reported directly, it is estimated from the F–V curve.
ΔF/F per AP	17.1% (median of 2 measurements: 14.6%)	Fluorescence change per single action potential in neurons. The table shows the first listed measurement; the median across measurements (one-photon preferred) is used for sorting.
AP width (FWHM, ms)	4.8 ms	Full width at half maximum of the optical spike waveform.
Photostability t75% @ 100 mW/mm²	4.7 min	Time for fluorescence to fall to 75% of its initial value under one-photon illumination, linearly dose-scaled to 100 mW/mm² (t50% is used where the 75% crossing falls inside a fast initial transient). Two-photon curves are not dose-scaled and are excluded.
Papers using it (N_used)	1	Number of published research papers, tracked by GEVIBench, that used the sensor for an experiment (a popularity / track-record measure).

Measurements and sources

Kinetics

τ_on 1.34 ms, τ_off 3.74 ms at 21-23°C — Cao 2025, Fig. S2

ΔF/F per 100 mV

-33.1%, 1P — Cao 2025, Table S2

ΔF/F per action potential

17.1%, 1P — Cao 2025, Table S2
12%, 1P — Cao 2025, Fig. 3A

AP width (FWHM)

4.8 ms at 400 Hz sampling, Mouse, thalamic neurons, acute brain slice, 1P, 34.5°C — Cao 2025, Fig. 3C

Brightness comparisons

2× the brightness of Ace2N-mNeon2 — Cao 2025, Fig. 1B
8× the brightness of JEDI-1P — Cao 2025, Fig. 1B

Photobleaching

t75% = 946 s at 30 mW/mm², 1P — Cao 2025, Fig. 1D

Fluorescence–voltage (F–V) curve

ΔF/F (%) at each membrane potential, normalized to 0 at −70 mV: -100 mV: 13%; -80 mV: 5%; -70 mV: 0%; -60 mV: -5%; -40 mV: -15%; -20 mV: -23%; 0 mV: -29%; 20 mV: -33%; 40 mV: -36%; 60 mV: -38%; 80 mV: -40%; 100 mV: -41% — Cao 2025, Fig. 1C

Research papers using Vega (1)

A photostable genetically encoded voltage indicator for imaging neural activities in tissue and live animals — Cao C, Zhu R, Zhou S, Zhao Z, Lin C, Liu S, Peng L, Subach FV, Piatkevich KD, Zou P, bioRxiv 2025 (HEK293T cells; Rat, hippocampal neurons, in vitro; Mouse, thalamic acute brain slices, ex vivo; Mouse, pancreatic islets, ex vivo; Mouse, visual cortex, in vivo)

Data and citation

llms.txt — summary for language models
llms-full.txt — every sensor in full (Markdown)
gevis.json — all values and measurements with sources (JSON)
gevis.csv — one row per sensor (CSV)

Cite GEVIBench as: Adam E. Cohen and Daozheng Gong (2026). Voltage imaging: A practical guide. Neuron. https://doi.org/10.1016/j.neuron.2026.08.002

Generated from the GEVIBench database on 2026-10-12.