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Koyama Lab / Publications
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25 Publications

Showing 1-10 of 25 results
08/20/20 | Rational design of bioavailable photosensitizers for manipulation and imaging of biological systems.
Binns TC, Ayala AX, Grimm JB, Tkachuk AN, Castillon GA, Phan S, Zhang L, Brown TA, Liu Z, Adams SR, Ellisman MH, Koyama M, Lavis LD
Cell Chemical Biology. 2020 Aug 20;27(8):1063-72. doi: 10.1016/j.chembiol.2020.07.001

Light-mediated chemical reactions are powerful methods for manipulating and interrogating biological systems. Photosensitizers, compounds that generate reactive oxygen species upon excitation with light, can be utilized for numerous biological experiments, but the repertoire of bioavailable photosensitizers is limited. Here, we describe the synthesis, characterization, and utility of two photosensitizers based upon the widely used rhodamine scaffold and demonstrate their efficacy for chromophore-assisted light inactivation, cell ablation in culture and in vivo, and photopolymerization of diaminobenzidine for electron microscopy. These chemical tools will facilitate a broad range of applications spanning from targeted destruction of proteins to high-resolution imaging.

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07/27/20 | A programmable sequence of reporters for lineage analysis.
Garcia-Marques J, Espinosa-Medina I, Ku K, Yang C, Koyama M, Yu H, Lee T
Nature Neuroscience. 2020 Jul 27:. doi: 10.1038/s41593-020-0676-9

We present CLADES (cell lineage access driven by an edition sequence), a technology for cell lineage studies based on CRISPR-Cas9 techniques. CLADES relies on a system of genetic switches to activate and inactivate reporter genes in a predetermined order. Targeting CLADES to progenitor cells allows the progeny to inherit a sequential cascade of reporters, thereby coupling birth order to reporter expression. This system, which can also be temporally induced by heat shock, enables the temporal resolution of lineage development and can therefore be used to deconstruct an extended cell lineage by tracking the reporters expressed in the progeny. When targeted to the germ line, the same cascade progresses across animal generations, predominantly marking each generation with the corresponding combination of reporters. CLADES therefore offers an innovative strategy for making programmable cascades of genes that can be used for genetic manipulation or to record serial biological events.

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07/10/20 | A general approach to engineer positive-going eFRET voltage indicators
Abdelfattah AS, Valenti R, Zheng J, Wong A, Podgorski K, Koyama M, Kim DS, Schreiter ER
Nature Communications. 2020 Jul 10;11(1):

We engineered electrochromic fluorescence resonance energy transfer (eFRET) genetically encoded voltage indicators (GEVIs) with “positive-going” fluorescence response to membrane depolarization through rational manipulation of the native proton transport pathway in microbial rhodopsins. We transformed the state-of-the-art eFRET GEVI Voltron into Positron, with kinetics and sensitivity equivalent to Voltron but flipped fluorescence signal polarity. We further applied this general approach to GEVIs containing different voltage sensitive rhodopsin domains and various fluorescent dye and fluorescent protein reporters.

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02/25/20 | High-throughput cellular-resolution synaptic connectivity mapping in vivo with concurrent two-photon optogenetics and volumetric Ca2+ imaging
McRaven C, Tanese D, Zhang L, Yang C, Ahrens MB, Emiliani V, Koyama M
bioRxiv. 2020 Feb 25:. doi: https://doi.org/10.1101/2020.02.21.959650

The ability to measure synaptic connectivity and properties is essential for understanding neuronal circuits. However, existing methods that allow such measurements at cellular resolution are laborious and technically demanding. Here, we describe a system that allows such measurements in a high-throughput way by combining two-photon optogenetics and volumetric Ca2+ imaging with whole-cell recording. We reveal a circuit motif for generating fast undulatory locomotion in zebrafish.

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02/08/20 | A fast genetically encoded fluorescent sensor for faithful in vivo acetylcholine detection in mice, fish, worms and flies.
Borden P, Zhang P, Shivange AV, Marvin JS, Cichon J, Dan C, Podgorski K, Figueiredo A, Novak O, Tanimoto M, Shigetomi E, Lobas MA, Kim H, Zhu P, Zhang Y, Zheng WS, Fan C, Wang G, Xiang B, Gan L, Zhang G, Guo K, Lin L, Cai Y, Yee AG, Aggarwal A, Ford CP, Rees DC, Dietrich D, Khakh BS, Dittman JS, Gan W, Koyama M, Jayaraman V, Cheer JF, Lester HA, Zhu JJ, Looger LL
bioRxiv. 2020 Feb 8:. doi: https://doi.org/10.1101/2020.02.07.939504

Here we design and optimize a genetically encoded fluorescent indicator, iAChSnFR, for the ubiquitous neurotransmitter acetylcholine, based on a bacterial periplasmic binding protein. iAChSnFR shows large fluorescence changes, rapid rise and decay kinetics, and insensitivity to most cholinergic drugs. iAChSnFR revealed large transients in a variety of slice and in vivo preparations in mouse, fish, fly and worm. iAChSnFR will be useful for the study of acetylcholine in all animals.

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10/23/19 | Unlimited genetic switches for cell-type-specific manipulation.
Garcia-Marques J, Yang C, Espinosa-Medina I, Mok K, Koyama M, Lee T
Neuron. 2019 Oct 23;104(2):227-38. doi: https://doi.org/10.1016/j.neuron.2019.07.005

Gaining independent genetic access to discrete cell types is critical to interrogate their biological functions as well as to deliver precise gene therapy. Transcriptomics has allowed us to profile cell populations with extraordinary precision, revealing that cell types are typically defined by a unique combination of genetic markers. Given the lack of adequate tools to target cell types based on multiple markers, most cell types remain inaccessible to genetic manipulation. Here we present CaSSA, a platform to create unlimited genetic switches based on CRISPR/Cas9 (Ca) and the DNA repair mechanism known as single-strand annealing (SSA). CaSSA allows engineering of independent genetic switches, each responding to a specific gRNA. Expressing multiple gRNAs in specific patterns enables multiplex cell-type-specific manipulations and combinatorial genetic targeting. CaSSA is a new genetic tool that conceptually works as an unlimited number of recombinases and will facilitate genetic access to cell types in diverse organisms.

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09/23/19 | Single-cell reconstruction of emerging population activity in an entire developing circuit.
Wan Y, Wei Z, Looger LL, Koyama M, Druckmann S, Keller PJ
Cell. 2019 Sep 23;179(2):. doi: 10.1016/j.cell.2019.08.039

Animal survival requires a functioning nervous system to develop during embryogenesis. Newborn neurons must assemble into circuits producing activity patterns capable of instructing behaviors. Elucidating how this process is coordinated requires new methods that follow maturation and activity of all cells across a developing circuit. We present an imaging method for comprehensively tracking neuron lineages, movements, molecular identities, and activity in the entire developing zebrafish spinal cord, from neurogenesis until the emergence of patterned activity instructing the earliest spontaneous motor behavior. We found that motoneurons are active first and form local patterned ensembles with neighboring neurons. These ensembles merge, synchronize globally after reaching a threshold size, and finally recruit commissural interneurons to orchestrate the left-right alternating patterns important for locomotion in vertebrates. Individual neurons undergo functional maturation stereotypically based on their birth time and anatomical origin. Our study provides a general strategy for reconstructing how functioning circuits emerge during embryogenesis.

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08/13/19 | Bright and photostable chemigenetic indicators for extended in vivo voltage imaging.
Abdelfattah AS, Kawashima T, Singh A, Novak O, Liu H, Shuai Y, Huang Y, Campagnola L, Seeman SC, Yu J, Zheng J, Grimm JB, Patel R, Friedrich J, Mensh BD, Paninski L, Macklin JJ, Murphy GJ, Podgorski K, Lin B, Chen T, Turner GC, Liu Z, Koyama M, Svoboda K, Ahrens MB, Lavis LD, Schreiter ER
Science. 2019 Aug 13;365(6454):699-704. doi: 10.1126/science.aav6416

Imaging changes in membrane potential using genetically encoded fluorescent voltage indicators (GEVIs) has great potential for monitoring neuronal activity with high spatial and temporal resolution. Brightness and photostability of fluorescent proteins and rhodopsins have limited the utility of existing GEVIs. We engineered a novel GEVI, "Voltron", that utilizes bright and photostable synthetic dyes instead of protein-based fluorophores, extending the combined duration of imaging and number of neurons imaged simultaneously by more than tenfold relative to existing GEVIs. We used Voltron for in vivo voltage imaging in mice, zebrafish, and fruit flies. In mouse cortex, Voltron allowed single-trial recording of spikes and subthreshold voltage signals from dozens of neurons simultaneously, over 15 min of continuous imaging. In larval zebrafish, Voltron enabled the precise correlation of spike timing with behavior.

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05/30/19 | CLADES: a programmable sequence of reporters for lineage analysis
Garcia-Marques J, Yang C, Espinosa-Medina I, Koyama M, Lee T
bioRxiv. 2019 May 30:. doi: https://doi.org/10.1101/655308

We present CLADES (Cell Lineage Access Driven by an Edition Sequence), a technology for cell lineage studies based on CRISPR/Cas9. CLADES relies on a system of genetic switches to activate and inactivate reporter genes in a pre-determined order. Targeting CLADES to progenitor cells allows the progeny to inherit a sequential cascade of reporters, coupling birth order with reporter expression. This gives us temporal resolution of lineage development that can be used to deconstruct an extended cell lineage by tracking the reporters expressed in the progeny. When targeted to the germ line, the same cascade progresses across animal generations, marking each generation with the corresponding combination of reporters. CLADES thus offers an innovative strategy for making programmable cascades of genes that can be used for genetic manipulation or to record serial biological events.

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04/26/19 | Dynamic super-resolution structured illumination imaging in the living brain.
Turcotte R, Liang Y, Tanimoto M, Zhang Q, Li Z, Koyama M, Betzig E, Ji N
Proceedings of the National Academy of Sciences of the United States of America. 2019 Apr 26;116(19):9586-91. doi: 10.1073/pnas.1819965116

Cells in the brain act as components of extended networks. Therefore, to understand neurobiological processes in a physiological context, it is essential to study them in vivo. Super-resolution microscopy has spatial resolution beyond the diffraction limit, thus promising to provide structural and functional insights that are not accessible with conventional microscopy. However, to apply it to in vivo brain imaging, we must address the challenges of 3D imaging in an optically heterogeneous tissue that is constantly in motion. We optimized image acquisition and reconstruction to combat sample motion and applied adaptive optics to correcting sample-induced optical aberrations in super-resolution structured illumination microscopy (SIM) in vivo. We imaged the brains of live zebrafish larvae and mice and observed the dynamics of dendrites and dendritic spines at nanoscale resolution.

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