A Flp-dependent G-CaMP9a transgenic mouse for neuronal imaging in vivo

Masayuki Sakamoto; Masatoshi Inoue; Atsuya Takeuchi; Shigetaka Kobari; Tatsushi Yokoyama; Shin-Ichiro Horigane; Sayaka Takemoto-Kimura; Manabu Abe; Kenji Sakimura; Masanobu Kano; Kazuo Kitamura; Hajime Fujii; Haruhiko Bito

doi:10.1016/j.crmeth.2022.100168

A Flp-dependent G-CaMP9a transgenic mouse for neuronal imaging in vivo

Cell Rep Methods. 2022 Feb 14;2(2):100168. doi: 10.1016/j.crmeth.2022.100168. eCollection 2022 Feb 28.

Authors

Masayuki Sakamoto^{1

2

3}, Masatoshi Inoue^{1

4}, Atsuya Takeuchi^{5

6}, Shigetaka Kobari¹, Tatsushi Yokoyama^{1

2}, Shin-Ichiro Horigane^{1

7

8}, Sayaka Takemoto-Kimura^{1

3

7

8}, Manabu Abe⁹, Kenji Sakimura⁹, Masanobu Kano^{5

10}, Kazuo Kitamura^{5

11}, Hajime Fujii¹, Haruhiko Bito^{1

10}

Affiliations

¹ Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Hongo7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.
² Department of Optical Neural and Molecular Physiology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8507, Japan.
³ Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Kyoto 606-8507, Japan.
⁴ Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
⁵ Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
⁶ Department of Neurophysiology, School of Dentistry, Tokyo Medical and Dental University, Tokyo, Japan.
⁷ Department of Neuroscience I, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi 464-8602, Japan.
⁸ Department of Molecular/Cellular Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan.
⁹ Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata 951-8585, Japan.
¹⁰ International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
¹¹ Department of Neurophysiology, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan.

Abstract

Genetically encoded calcium indicators (GECIs) are widely used to measure calcium transients in neuronal somata and processes, and their use enables the determination of action potential temporal series in a large population of neurons. Here, we generate a transgenic mouse line expressing a highly sensitive green GECI, G-CaMP9a, in a Flp-dependent manner in excitatory and inhibitory neuronal subpopulations downstream of a strong CAG promoter. Combining this reporter mouse with viral or mouse genetic Flp delivery methods produces a robust and stable G-CaMP9a expression in defined neuronal populations without detectable detrimental effects. In vivo two-photon imaging reveals spontaneous and sensory-evoked calcium transients in excitatory and inhibitory ensembles with cellular resolution. Our results show that this reporter line allows long-term, cell-type-specific investigation of neuronal activity with enhanced resolution in defined populations and facilitates dissecting complex dynamics of neural networks in vivo.

Keywords: Flp/Frt recombination; dual-color imaging; genetically encoded calcium indicator; in vivo calcium imaging; transgenic mouse; two-photon microscopy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Action Potentials
Animals
Calcium* / metabolism
Mice
Mice, Transgenic
Neuroimaging*
Neurons*

Substances

Calcium