1
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Chai F, Fujii H, Le GNT, Lin C, Ota K, Lin KM, Pham LMT, Zou P, Drobizhev M, Nasu Y, Terai T, Bito H, Campbell RE. Development of an miRFP680-Based Fluorescent Calcium Ion Biosensor Using End-Optimized Transposons. ACS Sens 2024; 9:3394-3402. [PMID: 38822813 PMCID: PMC11218748 DOI: 10.1021/acssensors.4c00727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/14/2024] [Accepted: 05/17/2024] [Indexed: 06/03/2024]
Abstract
The development of new or improved single fluorescent protein (FP)-based biosensors (SFPBs), particularly those with excitation and emission at near-infrared wavelengths, is important for the continued advancement of biological imaging applications. In an effort to accelerate the development of new SFPBs, we report modified transposons for the transposase-based creation of libraries of FPs randomly inserted into analyte binding domains, or vice versa. These modified transposons feature ends that are optimized to minimize the length of the linkers that connect the FP to the analyte binding domain. We rationalized that shorter linkers between the domains should result in more effective allosteric coupling between the analyte binding-dependent conformational change in the binding domain and the fluorescence modulation of the chromophore of the FP domain. As a proof of concept, we employed end-modified Mu transposons for the discovery of SFPB prototypes based on the insertion of two circularly permuted red FPs (mApple and FusionRed) into binding proteins for l-lactate and spermidine. Using an analogous approach, we discovered calcium ion (Ca2+)-specific SFPBs by random insertion of calmodulin (CaM)-RS20 into miRFP680, a particularly bright near-infrared (NIR) FP based on a biliverdin (BV)-binding fluorescent protein. Starting from an miRFP680-based Ca2+ biosensor prototype, we performed extensive directed evolution, including under BV-deficient conditions, to create highly optimized biosensors designated the NIR-GECO3 series. We have extensively characterized the NIR-GECO3 series and explored their utility for biological Ca2+ imaging. The methods described in this work will serve to accelerate SFPB development and open avenues for further exploration and optimization of SFPBs across a spectrum of biological applications.
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Affiliation(s)
- Fu Chai
- Department
of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hajime Fujii
- Department
of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Giang N. T. Le
- Department
of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Chang Lin
- College
of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Keisuke Ota
- Department
of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Karl Matthew Lin
- Department
of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Lam M. T. Pham
- Department
of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Peng Zou
- College
of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Mikhail Drobizhev
- Department
of Microbiology and Cell Biology, Montana
State University, Bozeman, Montana 59717, United States
| | - Yusuke Nasu
- Department
of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- PRESTO,
Japan Science and Technology Agency,
Chiyoda-ku, Tokyo 102-0075, Japan
| | - Takuya Terai
- Department
of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Haruhiko Bito
- Department
of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Robert E. Campbell
- Department
of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- CERVO
Brain Research Center and Department of Biochemistry, Microbiology,
and Bioinformatics, Université Laval, Québec, Québec G1 V 0A6, Canada
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2
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Nam KH, Xu Y. Structural Analysis of the Large Stokes Shift Red Fluorescent Protein tKeima. Molecules 2024; 29:2579. [PMID: 38893454 PMCID: PMC11173989 DOI: 10.3390/molecules29112579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 05/25/2024] [Accepted: 05/29/2024] [Indexed: 06/21/2024] Open
Abstract
The Keima family comprises large Stokes shift fluorescent proteins that are useful for dual-color fluorescence cross-correlation spectroscopy and multicolor imaging. The tKeima is a tetrameric large Stokes shift fluorescent protein and serves as the ancestor fluorescent protein for both dKeima and mKeima. The spectroscopic properties of tKeima have been previously reported; however, its structural basis and molecular properties have not yet been elucidated. In this study, we present the crystallographic results of the large Stokes shift fluorescent protein tKeima. The purified tKeima protein spontaneously crystallized after purification without further crystallization. The crystal structure of tKeima was determined at 3.0 Å resolution, revealing a β-barrel fold containing the Gln-Tyr-Gly chromophores mainly with cis-conformation. The tetrameric interfaces of tKeima were stabilized by numerous hydrogen bonds and salt-bridge interactions. These key residues distinguish the substituted residues in dKeima and mKeima. The key structure-based residues involved in the tetramer formation of tKeima provide insights into the generation of a new type of monomeric mKeima. This structural analysis expands our knowledge of the Keima family and provides insights into its protein engineering.
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Affiliation(s)
- Ki Hyun Nam
- College of General Education, Kookmin University, Seoul 02707, Republic of Korea
| | - Yongbin Xu
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian 116600, China
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3
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Beyrent E, Wei DT, Beacham GM, Park S, Zheng J, Paszek MJ, Hollopeter G. Dimerization activates the Inversin complex in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.17.594761. [PMID: 38798613 PMCID: PMC11118560 DOI: 10.1101/2024.05.17.594761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Genetic, colocalization, and biochemical studies suggest that the ankyrin repeat-containing proteins Inversin (INVS) and ANKS6 function with the NEK8 kinase to control tissue patterning and maintain organ physiology. It is unknown whether these three proteins assemble into a static "Inversin complex" or one that adopts multiple bioactive forms. Through characterization of hyperactive alleles in C. elegans , we discovered that the Inversin complex is activated by dimerization. Genome engineering of an RFP tag onto the nematode homologs of INVS (MLT-4) and NEK8 (NEKL-2) induced a gain-of-function, cyst-like phenotype that was suppressed by monomerization of the fluorescent tag. Stimulated dimerization of MLT-4 or NEKL-2 using optogenetics was sufficient to recapitulate the phenotype of a constitutively active Inversin complex. Further, dimerization of NEKL-2 bypassed a lethal MLT-4 mutant, demonstrating that the dimeric form is required for function. We propose that dynamic switching between at least two functionally distinct states-an active dimer and an inactive monomer-gates the output of the Inversin complex.
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4
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Lu K, Wazawa T, Matsuda T, Shcherbakova DM, Verkhusha VV, Nagai T. Near-infrared PAINT localization microscopy via chromophore replenishment of phytochrome-derived fluorescent tag. Commun Biol 2024; 7:473. [PMID: 38637683 PMCID: PMC11026395 DOI: 10.1038/s42003-024-06169-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 04/09/2024] [Indexed: 04/20/2024] Open
Abstract
Bacterial phytochromes are attractive molecular templates for engineering fluorescent proteins (FPs) because their near-infrared (NIR) emission significantly extends the spectral coverage of GFP-like FPs. Existing phytochrome-based FPs covalently bind heme-derived tetrapyrrole chromophores and exhibit constitutive fluorescence. Here we introduce Rep-miRFP, an NIR imaging probe derived from bacterial phytochrome, which interacts non-covalently and reversibly with biliverdin chromophore. In Rep-miRFP, the photobleached non-covalent adduct can be replenished with fresh biliverdin, restoring fluorescence. By exploiting this chromophore renewal capability, we demonstrate NIR PAINT nanoscopy in mammalian cells using Rep-miRFP.
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Affiliation(s)
- Kai Lu
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan
| | - Tetsuichi Wazawa
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan
| | - Tomoki Matsuda
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan
| | - Daria M Shcherbakova
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Vladislav V Verkhusha
- Department of Genetics and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, 00290, Finland
| | - Takeharu Nagai
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan.
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5
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Tomris I, van der Woude R, de Paiva Froes Rocha R, Torrents de la Peña A, Ward AB, de Vries RP. Viral envelope proteins fused to multiple distinct fluorescent reporters to probe receptor binding. Protein Sci 2024; 33:e4974. [PMID: 38533540 DOI: 10.1002/pro.4974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 03/04/2024] [Accepted: 03/13/2024] [Indexed: 03/28/2024]
Abstract
Enveloped viruses carry one or multiple proteins with receptor-binding functionalities. Functional receptors can be glycans, proteinaceous, or both; therefore, recombinant protein approaches are instrumental in attaining new insights regarding viral envelope protein receptor-binding properties. Visualizing and measuring receptor binding typically entails antibody detection or direct labeling, whereas direct fluorescent fusions are attractive tools in molecular biology. Here, we report a suite of distinct fluorescent fusions, both N- and C-terminal, for influenza A virus hemagglutinins and SARS-CoV-2 spike RBD. The proteins contained three or six fluorescent protein barrels and were applied directly to cells to assess receptor binding properties.
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Affiliation(s)
- Ilhan Tomris
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, The Netherlands
| | - Roosmarijn van der Woude
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, The Netherlands
| | - Rebeca de Paiva Froes Rocha
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Alba Torrents de la Peña
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Robert P de Vries
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, The Netherlands
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6
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Yabushita A, Cheng CY, Ko YK, Kobayashi T, Iwakura I, Jimenez R. Excited State Vibrational Dynamics Reveals a Photocycle That Enhances the Photostability of the TagRFP-T Fluorescent Protein. J Phys Chem B 2024; 128:1188-1193. [PMID: 38282329 PMCID: PMC10860143 DOI: 10.1021/acs.jpcb.3c07212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/13/2024] [Accepted: 01/17/2024] [Indexed: 01/30/2024]
Abstract
High photostability is a desirable property of fluorescent proteins (FPs) for imaging, yet its molecular basis is poorly understood. We performed ultrafast spectroscopy on TagRFP and its 9-fold more photostable variant TagRFP-T (TagRFP S158T) to characterize their initial photoreactions. We find significant differences in their electronic and vibrational dynamics, including faster excited-state proton transfer and transient changes in the frequency of the v520 mode in the excited electronic state of TagRFP-T. The frequency of v520, which is sensitive to chromophore planarity, downshifts within 0.58 ps and recovers within 0.87 ps. This vibrational mode modulates the distance from the chromophore phenoxy to the side chain of residue N143, which we suggest can trigger cis/trans photoisomerization. In TagRFP, the dynamics of v520 is missing, and this FP therefore lacks an important channel for chromophore isomerization. These dynamics are likely to be a key mechanism differentiating the photostability of the two FPs.
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Affiliation(s)
- Atsushi Yabushita
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
- Research Institute for Engineering, Kanagawa University, Yokohama 2210802, Japan
| | - Chia-Yun Cheng
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Ying Kuan Ko
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Takayoshi Kobayashi
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
- Advanced Ultrafast Laser Research Center, The University of Electro-Communications, Chofu 1828585, Japan
| | - Izumi Iwakura
- Department of Chemistry, Faculty of Engineering, Kanagawa University, Yokohama 2218686, Japan
| | - Ralph Jimenez
- JILA, National Institute of Standards and Technology and University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
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7
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Scheele CLGJ, Herrmann D, Yamashita E, Celso CL, Jenne CN, Oktay MH, Entenberg D, Friedl P, Weigert R, Meijboom FLB, Ishii M, Timpson P, van Rheenen J. Multiphoton intravital microscopy of rodents. NATURE REVIEWS. METHODS PRIMERS 2022; 2:89. [PMID: 37621948 PMCID: PMC10449057 DOI: 10.1038/s43586-022-00168-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/12/2022] [Indexed: 08/26/2023]
Abstract
Tissues are heterogeneous with respect to cellular and non-cellular components and in the dynamic interactions between these elements. To study the behaviour and fate of individual cells in these complex tissues, intravital microscopy (IVM) techniques such as multiphoton microscopy have been developed to visualize intact and live tissues at cellular and subcellular resolution. IVM experiments have revealed unique insights into the dynamic interplay between different cell types and their local environment, and how this drives morphogenesis and homeostasis of tissues, inflammation and immune responses, and the development of various diseases. This Primer introduces researchers to IVM technologies, with a focus on multiphoton microscopy of rodents, and discusses challenges, solutions and practical tips on how to perform IVM. To illustrate the unique potential of IVM, several examples of results are highlighted. Finally, we discuss data reproducibility and how to handle big imaging data sets.
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Affiliation(s)
- Colinda L. G. J. Scheele
- Laboratory for Intravital Imaging and Dynamics of Tumor Progression, VIB Center for Cancer Biology, KU Leuven, Leuven, Belgium
- Department of Oncology, KU Leuven, Leuven, Belgium
| | - David Herrmann
- Cancer Ecosystems Program, Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Department, Sydney, New South Wales, Australia
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
| | - Erika Yamashita
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
- Laboratory of Bioimaging and Drug Discovery, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - Cristina Lo Celso
- Department of Life Sciences and Centre for Hematology, Imperial College London, London, UK
- Sir Francis Crick Institute, London, UK
| | - Craig N. Jenne
- Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Maja H. Oktay
- Department of Pathology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA
- Integrated Imaging Program, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA
| | - David Entenberg
- Department of Pathology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA
- Integrated Imaging Program, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA
| | - Peter Friedl
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, Netherlands
- David H. Koch Center for Applied Genitourinary Cancers, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Franck L. B. Meijboom
- Department of Population Health Sciences, Sustainable Animal Stewardship, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
- Faculty of Humanities, Ethics Institute, Utrecht University, Utrecht, Netherlands
| | - Masaru Ishii
- Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan
- WPI-Immunology Frontier Research Center, Osaka University, Osaka, Japan
- Laboratory of Bioimaging and Drug Discovery, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - Paul Timpson
- Cancer Ecosystems Program, Garvan Institute of Medical Research and The Kinghorn Cancer Centre, Cancer Department, Sydney, New South Wales, Australia
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Sydney, New South Wales, Australia
| | - Jacco van Rheenen
- Division of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, Netherlands
- Division of Molecular Pathology, Oncode Institute, The Netherlands Cancer Institute, Amsterdam, Netherlands
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8
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Wai DCC, Naseem MU, Mocsár G, Babu Reddiar S, Pan Y, Csoti A, Hajdu P, Nowell C, Nicolazzo JA, Panyi G, Norton RS. Fluorescent Peptide Toxin for Selective Visualization of the Voltage-Gated Potassium Channel K V1.3. Bioconjug Chem 2022; 33:2197-2212. [DOI: 10.1021/acs.bioconjchem.2c00436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Dorothy C. C. Wai
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
| | - Muhammad Umair Naseem
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
| | - Gábor Mocsár
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
- Damjanovich Cell Analysis Core Facility, Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
| | - Sanjeevini Babu Reddiar
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
| | - Yijun Pan
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
| | - Agota Csoti
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
| | - Peter Hajdu
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
- Department of Dental Biochemistry, Faculty of Dentistry, University of Debrecen, Debrecen4032, Hungary
| | - Cameron Nowell
- Imaging, FACS and Analysis Core, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
| | - Joseph A. Nicolazzo
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen4032, Hungary
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria3052, Australia
- ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria3052, Australia
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9
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Fages-Lartaud M, Tietze L, Elie F, Lale R, Hohmann-Marriott MF. mCherry contains a fluorescent protein isoform that interferes with its reporter function. Front Bioeng Biotechnol 2022; 10:892138. [PMID: 36017355 PMCID: PMC9395592 DOI: 10.3389/fbioe.2022.892138] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 06/30/2022] [Indexed: 11/13/2022] Open
Abstract
Fluorescent proteins are essential reporters in cell and molecular biology. Here, we found that red-fluorescent proteins possess an alternative translation initiation site that produces a short functional protein isoform in both prokaryotes and eukaryotes. The short isoform creates significant background fluorescence that biases the outcome of expression studies. In this study, we identified the short protein isoform, traced its origin, and determined the extent of the issue within the family of red fluorescent protein. Our analysis showed that the short isoform defect of the red fluorescent protein family may affect the interpretation of many published studies. We provided a re-engineered mCherry variant that lacks background expression as an improved tool for imaging and protein expression studies.
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Affiliation(s)
- Maxime Fages-Lartaud
- Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Lisa Tietze
- Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Florence Elie
- Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Rahmi Lale
- Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Martin Frank Hohmann-Marriott
- Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway
- United Scientists CORE (Limited), Dunedin, New Zealand
- *Correspondence: Martin Frank Hohmann-Marriott,
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10
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Zhang Y, Lu Y, El Sayyed H, Bian J, Lin J, Li X. Transcription factor dynamics in plants: Insights and technologies for in vivo imaging. PLANT PHYSIOLOGY 2022; 189:23-36. [PMID: 35134239 PMCID: PMC9070795 DOI: 10.1093/plphys/kiac042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 01/08/2022] [Indexed: 06/14/2023]
Abstract
Biochemical and genetic approaches have been extensively used to study transcription factor (TF) functions, but their dynamic behaviors and the complex ways in which they regulate transcription in plant cells remain unexplored, particularly behaviors such as translocation and binding to DNA. Recent developments in labeling and imaging techniques provide the necessary sensitivity and resolution to study these behaviors in living cells. In this review, we present an up-to-date portrait of the dynamics and regulation of TFs under physiologically relevant conditions and then summarize recent advances in fluorescent labeling strategies and imaging techniques. We then discuss future prospects and challenges associated with the application of these techniques to examine TFs' intricate dance in living plants.
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Affiliation(s)
- Yuan Zhang
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
| | - Yuqing Lu
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
| | - Hafez El Sayyed
- Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Jiahui Bian
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
| | - Jinxing Lin
- Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
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11
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Karsten L, Goett-Zink L, Schmitz J, Hoffrogge R, Grünberger A, Kottke T, Müller KM. Genetically Encoded Ratiometric pH Sensors for the Measurement of Intra- and Extracellular pH and Internalization Rates. BIOSENSORS 2022; 12:bios12050271. [PMID: 35624572 PMCID: PMC9138566 DOI: 10.3390/bios12050271] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/04/2022] [Accepted: 04/11/2022] [Indexed: 12/13/2022]
Abstract
pH-sensitive fluorescent proteins as genetically encoded pH sensors are promising tools for monitoring intra- and extracellular pH. However, there is a lack of ratiometric pH sensors, which offer a good dynamic range and can be purified and applied extracellularly to investigate uptake. In our study, the bright fluorescent protein CoGFP_V0 was C-terminally fused to the ligand epidermal growth factor (EGF) and retained its dual-excitation and dual-emission properties as a purified protein. The tandem fluorescent variants EGF-CoGFP-mTagBFP2 (pK′ = 6.6) and EGF-CoGFP-mCRISPRed (pK′ = 6.1) revealed high dynamic ranges between pH 4.0 and 7.5. Using live-cell fluorescence microscopy, both pH sensor molecules permitted the conversion of fluorescence intensity ratios to detailed intracellular pH maps, which revealed pH gradients within endocytic vesicles. Additionally, extracellular binding of the pH sensors to cells expressing the EGF receptor (EGFR) enabled the tracking of pH shifts inside cultivation chambers of a microfluidic device. Furthermore, the dual-emission properties of EGF-CoGFP-mCRISPRed upon 488 nm excitation make this pH sensor a valuable tool for ratiometric flow cytometry. This high-throughput method allowed for the determination of internalization rates, which represents a promising kinetic parameter for the in vitro characterization of protein–drug conjugates in cancer therapy.
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Affiliation(s)
- Lennard Karsten
- Cellular and Molecular Biotechnology, Faculty of Technology, Bielefeld University, 33615 Bielefeld, Germany;
| | - Lukas Goett-Zink
- Biophysical Chemistry and Diagnostics, Medical School OWL, Faculty of Chemistry, Bielefeld University, 33615 Bielefeld, Germany; (L.G.-Z.); (T.K.)
| | - Julian Schmitz
- Multiscale Bioengineering, Faculty of Technology, Bielefeld University, 33615 Bielefeld, Germany; (J.S.); (A.G.)
- Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - Raimund Hoffrogge
- Cell Culture Technology, Faculty of Technology, Bielefeld University, 33615 Bielefeld, Germany;
| | - Alexander Grünberger
- Multiscale Bioengineering, Faculty of Technology, Bielefeld University, 33615 Bielefeld, Germany; (J.S.); (A.G.)
- Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - Tilman Kottke
- Biophysical Chemistry and Diagnostics, Medical School OWL, Faculty of Chemistry, Bielefeld University, 33615 Bielefeld, Germany; (L.G.-Z.); (T.K.)
| | - Kristian M. Müller
- Cellular and Molecular Biotechnology, Faculty of Technology, Bielefeld University, 33615 Bielefeld, Germany;
- Correspondence:
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12
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Kim TY, Yoon TS, Kang S, Afzal M. Juggling with fluorescent proteins: Spectrum and structural changes of the mCardinal2 variants. Biochem Biophys Res Commun 2022; 593:79-83. [PMID: 35063773 DOI: 10.1016/j.bbrc.2022.01.044] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 01/06/2022] [Accepted: 01/12/2022] [Indexed: 11/16/2022]
Abstract
mCardinal2 is a red fluorescent protein developed through the designs of mKate, mNeptune and mCardinal. Fluorescence spectrums of mCardinal2 and its five mutants (T143C, T143G, C158A, C158D and M160E) were measured with their quantum yields. C158A and C158D increased brightness with slight changes in fluorescence spectrums while T143C, T143G and M160E decreased brightness with blue shift in fluorescence spectrums, which resulted in green, cyan and green fluorescent proteins respectively. Crystal structures of all six variants were analyzed and compared together with those of mKate, LSS-mKate1, LSS-mKate2 and mCardinal. Around the Cα-Cβ bond of Tyr64 in the MYG chromophores, only C158A and C158D were in the trans conformation while all others were mostly in the cis conformation. Blue-shift brightness-decreased variants (T143C, T143G and M160E) showed the diminished hydrogen bonds while large-Stoke-shift brightness-increased variant C158D showed the enhanced hydrogen bonds around the chromophore.
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Affiliation(s)
- Tae-Yeon Kim
- Disease Target Structure Research Center, Korea Research Institute Bioscience & Biotechnology, 125 Gwahak-Ro, Yuseong-Gu, Daejeon, 34141, South Korea; Proteomic Structural Biology, KRIBB School, University Science & Technology, 125 Gwahak-Ro, Yuseong-Gu, Daejeon, 34141, South Korea
| | - Tae-Sung Yoon
- Disease Target Structure Research Center, Korea Research Institute Bioscience & Biotechnology, 125 Gwahak-Ro, Yuseong-Gu, Daejeon, 34141, South Korea; Proteomic Structural Biology, KRIBB School, University Science & Technology, 125 Gwahak-Ro, Yuseong-Gu, Daejeon, 34141, South Korea.
| | - Sunghyun Kang
- Disease Target Structure Research Center, Korea Research Institute Bioscience & Biotechnology, 125 Gwahak-Ro, Yuseong-Gu, Daejeon, 34141, South Korea.
| | - Muhammad Afzal
- Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, South Korea.
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13
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Legault S, Fraser-Halberg DP, McAnelly RL, Eason MG, Thompson MC, Chica RA. Generation of bright monomeric red fluorescent proteins via computational design of enhanced chromophore packing. Chem Sci 2022; 13:1408-1418. [PMID: 35222925 PMCID: PMC8809391 DOI: 10.1039/d1sc05088e] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 01/07/2022] [Indexed: 12/11/2022] Open
Abstract
Red fluorescent proteins (RFPs) have found widespread application in chemical and biological research due to their longer emission wavelengths. Here, we use computational protein design to increase the quantum yield and thereby brightness of a dim monomeric RFP (mRojoA, quantum yield = 0.02) by optimizing chromophore packing with aliphatic residues, which we hypothesized would reduce torsional motions causing non-radiative decay. Experimental characterization of the top 10 designed sequences yielded mSandy1 (λ em = 609 nm, quantum yield = 0.26), a variant with equivalent brightness to mCherry, a widely used RFP. We next used directed evolution to further increase brightness, resulting in mSandy2 (λ em = 606 nm, quantum yield = 0.35), the brightest Discosoma sp. derived monomeric RFP with an emission maximum above 600 nm reported to date. Crystallographic analysis of mSandy2 showed that the chromophore p-hydroxybenzylidene moiety is sandwiched between the side chains of Leu63 and Ile197, a structural motif that has not previously been observed in RFPs, and confirms that aliphatic packing leads to chromophore rigidification. Our results demonstrate that computational protein design can be used to generate bright monomeric RFPs, which can serve as templates for the evolution of novel far-red fluorescent proteins.
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Affiliation(s)
- Sandrine Legault
- Department of Chemistry and Biomolecular Sciences, University of Ottawa 10 Marie-Curie Ottawa Ontario K1N 6N5 Canada
| | - Derek P Fraser-Halberg
- Department of Chemistry and Biomolecular Sciences, University of Ottawa 10 Marie-Curie Ottawa Ontario K1N 6N5 Canada
| | - Ralph L McAnelly
- Department of Chemistry and Biochemistry, University of California, Merced Merced California 95343 USA
| | - Matthew G Eason
- Department of Chemistry and Biomolecular Sciences, University of Ottawa 10 Marie-Curie Ottawa Ontario K1N 6N5 Canada
| | - Michael C Thompson
- Department of Chemistry and Biochemistry, University of California, Merced Merced California 95343 USA
| | - Roberto A Chica
- Department of Chemistry and Biomolecular Sciences, University of Ottawa 10 Marie-Curie Ottawa Ontario K1N 6N5 Canada
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14
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Chen C, Tutol JN, Tang L, Zhu L, Ong WSY, Dodani SC, Fang C. Excitation ratiometric chloride sensing in a standalone yellow fluorescent protein is powered by the interplay between proton transfer and conformational reorganization. Chem Sci 2021; 12:11382-11393. [PMID: 34667546 PMCID: PMC8447875 DOI: 10.1039/d1sc00847a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022] Open
Abstract
Natural and laboratory-guided evolution has created a rich diversity of fluorescent protein (FP)-based sensors for chloride (Cl−). To date, such sensors have been limited to the Aequorea victoria green fluorescent protein (avGFP) family, and fusions with other FPs have unlocked ratiometric imaging applications. Recently, we identified the yellow fluorescent protein from jellyfish Phialidium sp. (phiYFP) as a fluorescent turn-on, self-ratiometric Cl− sensor. To elucidate its working mechanism as a rare example of a single FP with this capability, we tracked the excited-state dynamics of phiYFP using femtosecond transient absorption (fs-TA) spectroscopy and target analysis. The photoexcited neutral chromophore undergoes bifurcated pathways with the twisting-motion-induced nonradiative decay and barrierless excited-state proton transfer. The latter pathway yields a weakly fluorescent anionic intermediate , followed by the formation of a red-shifted fluorescent state that enables the ratiometric response on the tens of picoseconds timescale. The redshift results from the optimized π–π stacking between chromophore Y66 and nearby Y203, an ultrafast molecular event. The anion binding leads to an increase of the chromophore pKa and ESPT population, and the hindrance of conversion. The interplay between these two effects determines the turn-on fluorescence response to halides such as Cl− but turn-off response to other anions such as nitrate as governed by different binding affinities. These deep mechanistic insights lay the foundation for guiding the targeted engineering of phiYFP and its derivatives for ratiometric imaging of cellular chloride with high selectivity. We discovered an interplay between proton transfer and conformational reorganization that powers a standalone fluorescent-protein-based excitation-ratiometric biosensor for chloride imaging.![]()
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Affiliation(s)
- Cheng Chen
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Jasmine N Tutol
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Longteng Tang
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Whitney S Y Ong
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Sheel C Dodani
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Chong Fang
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
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15
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Shcherbakova DM. Near-infrared and far-red genetically encoded indicators of neuronal activity. J Neurosci Methods 2021; 362:109314. [PMID: 34375713 DOI: 10.1016/j.jneumeth.2021.109314] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/15/2021] [Accepted: 08/05/2021] [Indexed: 12/18/2022]
Abstract
Genetically encoded fluorescent indicators of neuronal activity are ultimately developed to dissect functions of neuronal ensembles during behavior in living animals. Recent development of near-infrared shifted calcium and voltage indicators moved us closer to this goal and enabled crosstalk-free combination with blue light-controlled optogenetic tools for all-optical control and readout. Here I discuss designs of recent near-infrared and far-red calcium and voltage indicators, compare their properties and performance, and overview their applications to spectral multiplexing and in vivo imaging. I also provide perspectives for further development.
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Affiliation(s)
- Daria M Shcherbakova
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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16
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17
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Schuster LA, Reisch CR. A plasmid toolbox for controlled gene expression across the Proteobacteria. Nucleic Acids Res 2021; 49:7189-7202. [PMID: 34125913 PMCID: PMC8266580 DOI: 10.1093/nar/gkab496] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/19/2021] [Accepted: 05/24/2021] [Indexed: 11/16/2022] Open
Abstract
Controlled gene expression is fundamental for the study of gene function and our ability to engineer bacteria. However, there is currently no easy-to-use genetics toolbox that enables controlled gene expression in a wide range of diverse species. To facilitate the development of genetics systems in a fast, easy, and standardized manner, we constructed and tested a plasmid assembly toolbox that will enable the identification of well-regulated promoters in many Proteobacteria and potentially beyond. Each plasmid is composed of four categories of genetic parts (i) the origin of replication, (ii) resistance marker, (iii) promoter-regulator and (iv) reporter. The plasmids can be efficiently assembled using ligation-independent cloning, and any gene of interest can be easily inserted in place of the reporter. We tested this toolbox in nine different Proteobacteria and identified regulated promoters with over fifty-fold induction range in eight of these bacteria. We also constructed variant libraries that enabled the identification of promoter-regulators with varied expression levels and increased inducible fold change relative to the original promoter. A selection of over 50 plasmids, which contain all of the toolbox's genetic parts, are available for community use and will enable easy construction and testing of genetics systems in both model and non-model bacteria.
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Affiliation(s)
- Layla A Schuster
- Dept. of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32603, USA
| | - Christopher R Reisch
- Dept. of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32603, USA
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18
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Biswas S, Khimulya G, Alley EC, Esvelt KM, Church GM. Low-N protein engineering with data-efficient deep learning. Nat Methods 2021; 18:389-396. [PMID: 33828272 DOI: 10.1038/s41592-021-01100-y] [Citation(s) in RCA: 153] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 02/22/2021] [Indexed: 11/09/2022]
Abstract
Protein engineering has enormous academic and industrial potential. However, it is limited by the lack of experimental assays that are consistent with the design goal and sufficiently high throughput to find rare, enhanced variants. Here we introduce a machine learning-guided paradigm that can use as few as 24 functionally assayed mutant sequences to build an accurate virtual fitness landscape and screen ten million sequences via in silico directed evolution. As demonstrated in two dissimilar proteins, GFP from Aequorea victoria (avGFP) and E. coli strain TEM-1 β-lactamase, top candidates from a single round are diverse and as active as engineered mutants obtained from previous high-throughput efforts. By distilling information from natural protein sequence landscapes, our model learns a latent representation of 'unnaturalness', which helps to guide search away from nonfunctional sequence neighborhoods. Subsequent low-N supervision then identifies improvements to the activity of interest. In sum, our approach enables efficient use of resource-intensive high-fidelity assays without sacrificing throughput, and helps to accelerate engineered proteins into the fermenter, field and clinic.
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Affiliation(s)
- Surojit Biswas
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA.,Nabla Bio, Inc., Boston, MA, USA
| | | | - Ethan C Alley
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kevin M Esvelt
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - George M Church
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA. .,Department of Genetics, Harvard Medical School, Boston, MA, USA.
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19
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Sun T, Li T, Yi K, Yan G, Gao X. Fluorescent Protein Variants Generated by Reassembly between Skeleton and Chromophore. ACS OMEGA 2021; 6:2925-2933. [PMID: 33553911 PMCID: PMC7860096 DOI: 10.1021/acsomega.0c05299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/06/2021] [Indexed: 06/12/2023]
Abstract
Fluorescent proteins (FPs) can be used as intrinsic molecular tags to track the dynamic activity in live cells. To obtain variants in an available and massive manner is always a challenge. Here, we adopted a computer-based microarray synthesis method to realize the reassembly between the chromophore and the skeleton. DNAWorks was used to segment the input FP templates into a set of overlapping oligonucleotides (20-43 mer) with a balanced annealing temperature, G + C content, and codon frequency. The constitution of the chromophore was kept in the same section by switching the divided sites during segmentation and the codon was optimized to further keep the balanced parameters. The designed oligonucleotides were synthesized on photo-programmable microfluidic arrays. Sequence analysis and the subsequent conditional induced expression of FPs revealed that oligonucleotides were highly reassembled. Spectra, photostability, and molecular size detection of randomly selected variants showed that they were distinct monomeric proteins that preserved photoactivity. Our study provides an effective means of obtaining FP variants based on a computer-designed parallel synthesis.
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Affiliation(s)
- Tingting Sun
- College
of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang, Shandong 277160, China
| | - Tianpeng Li
- College
of Civil and Architecture Engineering, Zaozhuang
University, Zaozhuang, Shandong 277160, China
- School
of the Environment, Henan Normal University, Xinxiang, Henan 453007, China
- Shandong
Key Laboratory of Water Pollution Control and Resource Reuse, Shandong University, Qingdao, Shandong 266237, China
| | - Ke Yi
- Laboratory
of Medical Genetics, Central South University, Changsha 410008, Hunan, China
| | - Guoquan Yan
- Bioengineering
Institute, Zhejiang University of Science
and Technology, Hangzhou, Zhejiang 310018, China
| | - Xiaolian Gao
- Department
of Biology and Biochemistry, University
of Houston, Houston, Texas 77004-5001, United States
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20
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Montecinos-Franjola F, Lin JY, Rodriguez EA. Fluorescent proteins for in vivo imaging, where's the biliverdin? Biochem Soc Trans 2020; 48:2657-2667. [PMID: 33196077 DOI: 10.1042/bst20200444] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/20/2020] [Accepted: 10/26/2020] [Indexed: 12/13/2022]
Abstract
Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10-18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.
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Affiliation(s)
| | - John Y Lin
- School of Medicine, University of Tasmania, Hobart, Tasmania 7000, Australia
| | - Erik A Rodriguez
- Department of Chemistry, The George Washington University, Washington, DC 20052, U.S.A
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21
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Cambré A, Aertsen A. Bacterial Vivisection: How Fluorescence-Based Imaging Techniques Shed a Light on the Inner Workings of Bacteria. Microbiol Mol Biol Rev 2020; 84:e00008-20. [PMID: 33115939 PMCID: PMC7599038 DOI: 10.1128/mmbr.00008-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The rise in fluorescence-based imaging techniques over the past 3 decades has improved the ability of researchers to scrutinize live cell biology at increased spatial and temporal resolution. In microbiology, these real-time vivisections structurally changed the view on the bacterial cell away from the "watery bag of enzymes" paradigm toward the perspective that these organisms are as complex as their eukaryotic counterparts. Capitalizing on the enormous potential of (time-lapse) fluorescence microscopy and the ever-extending pallet of corresponding probes, initial breakthroughs were made in unraveling the localization of proteins and monitoring real-time gene expression. However, later it became clear that the potential of this technique extends much further, paving the way for a focus-shift from observing single events within bacterial cells or populations to obtaining a more global picture at the intra- and intercellular level. In this review, we outline the current state of the art in fluorescence-based vivisection of bacteria and provide an overview of important case studies to exemplify how to use or combine different strategies to gain detailed information on the cell's physiology. The manuscript therefore consists of two separate (but interconnected) parts that can be read and consulted individually. The first part focuses on the fluorescent probe pallet and provides a perspective on modern methodologies for microscopy using these tools. The second section of the review takes the reader on a tour through the bacterial cell from cytoplasm to outer shell, describing strategies and methods to highlight architectural features and overall dynamics within cells.
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Affiliation(s)
- Alexander Cambré
- KU Leuven, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Leuven, Belgium
| | - Abram Aertsen
- KU Leuven, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Leuven, Belgium
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22
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Bridges MC, Woodley CM, Peters EC, May LA, Galloway SB. Expression and Characterization of a Bright Far-red Fluorescent Protein from the Pink-Pigmented Tissues of Porites lobata. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2020; 22:67-80. [PMID: 31853751 DOI: 10.1007/s10126-019-09931-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 10/30/2019] [Indexed: 06/10/2023]
Abstract
Members of the anthozoan green fluorescent protein (GFP) family display a diversity of photo-physical properties that can be associated with normal and damaged coral tissues. Poritid coral species often exhibit localized pink pigmentation in diseased or damaged tissues. Our spectral and histological analyses of pink-pigmented Porites lobata lesions show co-localization of bright red fluorescence with putative amoebocytes concentrating in the epidermis, suggesting an activated innate immune response. Here we report the cloning, expression, and characterization of a novel red fluorescent protein (plobRFP) from the pink-pigmented tissues associated with lesions on Porites lobata. In vitro, the recombinant plobRFP exhibits a distinct red emission signal of 614 nm (excitation maximum: 578 nm), making plobRFP the furthest red-shifted natural fluorescent protein isolated from a scleractinian coral. The recombinant protein has a high molar extinction coefficient (84,000 M-1 cm-1) and quantum yield (0.74), conferring a notable brightness to plobRFP. Sequence analysis suggests the distinct brightness and marked red shift may be inherent features of plobRFP's chromophore conformation. While plobRFP displays a tendency to aggregate, its high pH stability, photostability, and spectral properties make it a candidate for cell imaging applications and a potential template for engineering optimized RFPs. The association of plobRFP with a possible immune response furthers its potential use as a visual diagnostic and molecular biomarker for monitoring coral health.
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Affiliation(s)
- Mary C Bridges
- Graduate Program in Marine Biology, College of Charleston, Charleston, SC, USA
- National Centers for Coastal Ocean Science Charleston Laboratory, NOS, NOAA, Charleston, SC, USA
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Cheryl M Woodley
- National Centers for Coastal Ocean Science Charleston Laboratory, NOS, NOAA, Charleston, SC, USA.
| | - Esther C Peters
- Department of Environmental Science & Policy, George Mason University, Fairfax, VA, USA
| | - Lisa A May
- Consolidated Safety Services, Inc., NCCOS Charleston Laboratory, NOS, NOAA, Charleston, SC, USA
| | - Sylvia B Galloway
- National Centers for Coastal Ocean Science Charleston Laboratory, NOS, NOAA, Charleston, SC, USA
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23
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Shcherbakova DM, Stepanenko OV, Turoverov KK, Verkhusha VV. Near-Infrared Fluorescent Proteins: Multiplexing and Optogenetics across Scales. Trends Biotechnol 2018; 36:1230-1243. [PMID: 30041828 DOI: 10.1016/j.tibtech.2018.06.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 06/28/2018] [Accepted: 06/29/2018] [Indexed: 10/28/2022]
Abstract
Since mammalian tissue is relatively transparent to near-infrared (NIR) light, NIR fluorescent proteins (FPs) engineered from bacterial phytochromes have become widely used probes for non-invasive in vivo imaging. Recently, these genetically encoded NIR probes have been substantially improved, enabling imaging experiments that were not possible previously. Here, we discuss the use of monomeric NIR FPs and NIR biosensors for multiplexed imaging with common visible GFP-based probes and blue light-activatable optogenetic tools. These NIR probes are suitable for visualization of functional activities from molecular to organismal levels. In combination with advanced imaging techniques, such as two-photon microscopy with adaptive optics, photoacoustic tomography and its recent modification reversibly switchable photoacoustic computed tomography, NIR probes allow subcellular resolution at millimeter depths.
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Affiliation(s)
- Daria M Shcherbakova
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Olesya V Stepanenko
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg 194064, Russian Federation
| | - Konstantin K Turoverov
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg 194064, Russian Federation; Department of Biophysics, Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195251, Russian Federation
| | - Vladislav V Verkhusha
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki 00290, Finland.
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