@article {69846, title = {Far-red fluorescent genetically encoded calcium ion indicators.}, journal = {Nat Commun}, volume = {16}, year = {2025}, month = {2025 Apr 07}, pages = {3318}, abstract = {

Genetically encoded calcium ion (Ca) indicators (GECIs) are widely-used molecular tools for functional imaging of Ca dynamics and neuronal activities with single-cell resolution. Here we report the design and development of two far-red fluorescent GECIs, FR-GECO1a and FR-GECO1c, based on the monomeric far-red fluorescent proteins mKelly1 and mKelly2. FR-GECOs have excitation and emission maxima at ~596 nm and ~644 nm, respectively, display large responses to Ca in vitro (ΔF/F = 6 for FR-GECO1a, 18 for FR-GECO1c), are bright under both one-photon and two-photon illumination, and have high affinities (apparent K = 29 nM for FR-GECO1a, 83 nM for FR-GECO1c) for Ca. FR-GECOs offer sensitive and fast detection of single action potentials in neurons, and enable in vivo all-optical manipulation and measurement of cellular activities in combination with optogenetic actuators.

Preprint:\ https://doi.org/10.1101/2020.11.12.380089

}, keywords = {Action Potentials, Animals, Calcium, Fluorescent Dyes, HEK293 Cells, Humans, Luminescent Proteins, Mice, Neurons, Optogenetics, Red Fluorescent Protein}, issn = {2041-1723}, doi = {10.1038/s41467-025-58485-z}, url = {https://doi.org/10.1038/s41467-025-58485-z}, author = {Dalangin, Rochelin and Jia, Bill Z and Qi, Yitong and Aggarwal, Abhi and Sakoi, Kenryo and Drobizhev, Mikhail and Molina, Rosana S and Patel, Ronak and Abdelfattah, Ahmed S and Zheng, Jihong and Reep, Daniel and Hasseman, Jeremy P and Zhao, Yufeng and Wu, Jiahui and Podgorski, Kaspar and Tebo, Alison G and Schreiter, Eric R and Hughes, Thomas E and Terai, Takuya and Paquet, Marie-Eve and Megason, Sean G and Cohen, Adam E and Shen, Yi and Campbell, Robert E} } @article {68561, title = {Time-tagged ticker tapes for intracellular recordings.}, journal = {Nature Biotechnology}, volume = {41}, year = {2023}, month = {2023 May 01}, pages = {631-9}, abstract = {

Recording transcriptional histories of a cell would enable deeper understanding of cellular developmental trajectories and responses to external perturbations. Here we describe an engineered protein fiber that incorporates diverse fluorescent marks during its growth to store a ticker tape-like history. An embedded HaloTag reporter incorporates user-supplied dyes, leading to colored stripes that map the growth of each individual fiber to wall clock time. A co-expressed eGFP tag driven by a promoter of interest records a history of transcriptional activation. High-resolution multi-spectral imaging on fixed samples reads the cellular histories, and interpolation of eGFP marks relative to HaloTag timestamps provides accurate absolute timing. We demonstrate recordings of doxycycline-induced transcription in HEK cells and cFos promoter activation in cultured neurons, with a single-cell absolute accuracy of 30-40 minutes over a 12-hour recording. The protein-based ticker tape design we present here could be generalized to achieve massively parallel single-cell recordings of diverse physiological modalities.

}, issn = {1546-1696}, doi = {10.1038/s41587-022-01524-7}, author = {Lin, Dingchang and Li, Xiuyuan and Moult, Eric and Park, Pojeong and Tang, Benjamin and Shen, Hao and Grimm, Jonathan B and Falco, Natalie and Jia, Bill Z and Baker, David and Lavis, Luke D and Cohen, Adam E} }