Considerations for expression of fluorescent proteins and imaging in mammalian cells

2021 ◽  
Author(s):  
Daniel Cabezas de la Fuente
Keyword(s):  
Mammalian Cells ◽  
Fluorescent Proteins

scholarly journals Genetically Encoded Fluorescent Sensor for Poly-ADP-Ribose

2020 ◽  
Vol 21 (14) ◽  
pp. 5004
Author(s):  
Ekaterina O. Serebrovskaya ◽  
Nadezda M. Podvalnaya ◽  
Varvara V. Dudenkova ◽  
Anna S. Efremova ◽  
Nadya G. Gurskaya ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Mammalian Cells ◽  
Fluorescent Proteins ◽  
Fluorescent Sensor ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Post Translational Modification ◽  
Cellular Processes ◽  
Hydrogen Peroxide Treatment ◽  
Damage Response

Poly-(ADP-ribosyl)-ation (PARylation) is a reversible post-translational modification of proteins and DNA that plays an important role in various cellular processes such as DNA damage response, replication, transcription, and cell death. Here we designed a fully genetically encoded fluorescent sensor for poly-(ADP-ribose) (PAR) based on Förster resonance energy transfer (FRET). The WWE domain, which recognizes iso-ADP-ribose internal PAR-specific structural unit, was used as a PAR-targeting module. The sensor consisted of cyan Turquoise2 and yellow Venus fluorescent proteins, each in fusion with the WWE domain of RNF146 E3 ubiquitin ligase protein. This bipartite sensor named sPARroW (sensor for PAR relying on WWE) enabled monitoring of PAR accumulation and depletion in live mammalian cells in response to different stimuli, namely hydrogen peroxide treatment, UV irradiation and hyperthermia.

scholarly journals A Single Atom Change Facilitates the Membrane Transport of Green Fluorescent Proteins in Mammalian Cells

2019 ◽  
Vol 131 (23) ◽  
pp. 7795-7799 ◽  
Author(s):  
Surendar R. Jakka ◽  
Vijayakumar Govindaraj ◽  
Govindasamy Mugesh
Keyword(s):  
Membrane Transport ◽  
Mammalian Cells ◽  
Fluorescent Proteins ◽  
Single Atom ◽  
Green Fluorescent Proteins ◽  
Green Fluorescent

scholarly journals Improved yellow-green split fluorescent proteins for protein labeling and signal amplification

2020 ◽  
Author(s):  
Shuqin Zhou ◽  
Siyu Feng ◽  
David Brown ◽  
Bo Huang
Keyword(s):  
Directed Evolution ◽  
Signal Amplification ◽  
Mammalian Cells ◽  
Rational Design ◽  
Fluorescent Proteins ◽  
Protein Labeling ◽  
Small Fragment ◽  
Wide Range ◽  
Split System ◽  
Low Expression

AbstractThe flexibility and versatility of self-complementing split fluorescent proteins (FPs) have enabled a wide range of applications. In particular, the FP1-10/11 split system contains a small fragment that facilitates efficient generation of endogenous-tagged cell lines and animals as well as signal amplification using tandem FP11 tags. To improve the FP1-10/11 toolbox we previously developed, here we used a combination of directed evolution and rational design approaches, resulting in two mNeonGreen (mNG)-based split FPs (mNG3A1-10/11 and mNG3K1-10/11) and one mClover-based split FP (CloGFP1-10/11). mNG3A1-10/11 and mNG3K1-10/11 not only enhanced the complementation efficiency at low expression levels, but also allowed us to demonstrate signal amplification using tandem mNG211 fragments in mammalian cells.

scholarly journals Distinguishing signal from autofluorescence in cryogenic correlated light and electron microscopy of mammalian cells

2017 ◽  
Author(s):  
Stephen D. Carter ◽  
Shrawan K. Mageswaran ◽  
Zachary J. Farino ◽  
João I. Mamede ◽  
Catherine M. Oikonomou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mammalian Cells ◽  
Fluorescent Protein ◽  
Organic Dyes ◽  
Fluorescent Proteins ◽  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Low Contrast ◽  
Fluorescent Protein Tags ◽  
Protein Tags

AbstractCryogenic correlated light and electron microscopy (cryo-CLEM) is a valuable tool for studying biological processes in situ. In cryo-CLEM, a target protein of interest is tagged with a fluorophore and the location of the corresponding fluorescent signal is used to identify the structure in low-contrast but feature-rich cryo-EM images. To date, cryo-CLEM studies of mammalian cells have relied on very bright organic dyes or fluorescent protein tags concentrated in virus particles. Here we describe a method to expand the application of cryo-CLEM to cells harboring genetically-encoded fluorescent proteins. We discovered that a variety of mammalian cells exhibit strong punctate autofluorescence when imaged under cryogenic conditions (80K). Compared to fluorescent protein tags, these sources of autofluorescence exhibit a broader spectrum of fluorescence, which we exploited to develop a simple, robust approach to discriminate between the two. We validate this method in INS-1 E cells using a mitochondrial marker, and apply it to study the ultrastructural variability of secretory granules in a near-native state within intact INS-1E pancreatic cells by high-resolution 3D electron cryotomography.

scholarly journals Quantitative assessment of near-infrared fluorescent proteins

2021 ◽  
Author(s):  
Kiryl Piatkevich ◽  
Hanbin Zhang ◽  
Stavrini Papadaki ◽  
Xiaoting Sun ◽  
Luxia Yao ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Quantitative Assessment ◽  
Near Infrared ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Oligomeric State ◽  
C Elegans ◽  
The Right ◽  
Infrared Fluorescent Protein

Abstract Recent progress in fluorescent protein development has generated a large diversity of near-infrared fluorescent proteins, which are rapidly becoming popular probes for a variety of imaging applications. To assist end-users with a selection of the right near-infrared fluorescent protein for a given application, we will conduct a quantitative assessment of intracellular brightness, photostability, and oligomeric state of 19 near-infrared fluorescent proteins in cultured mammalian cells. The top-performing proteins will be further validated for in vivo imaging of neurons in C. elegans, zebrafish, and mice. We will also assess the applicability of the selected NIR FPs for expansion microscopy and two-photon imaging.

scholarly journals Multi-parameter analysis of the kinetics of NF-κB signalling and transcription in single living cells

2002 ◽  
Vol 115 (6) ◽  
pp. 1137-1148 ◽  
Author(s):  
Glyn Nelson ◽  
Luminita Paraoan ◽  
David G. Spiller ◽  
Geraint J. C. Wilde ◽  
Mark A. Browne ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Activation ◽  
Nuclear Export ◽  
Mammalian Cells ◽  
Nuclear Translocation ◽  
Fluorescent Proteins ◽  
Parameter Analysis ◽  
Nuclear Accumulation ◽  
Fusion Protein Expression ◽  
Kinetics Of

Proteins of the NF-κB transcription factor family normally reside in the cytoplasm of cells in a complex with IκB inhibitor proteins. Stimulation with TNFα leads to proteosomal degradation of the IκB proteins and nuclear translocation of the NF-κB proteins. Expression of p65 and IκBα fused to fluorescent proteins was used to measure the dynamics of these processes in transfected HeLa cells. Simultaneous visualisation of p65-dsRed translocation and IκBα-EGFP degradation indicated that in the presence of dual fluorescent fusion protein expression,the half-time of IκBα-EGFP degradation was reduced and that of p65 translocation was significantly increased when compared with cells expressing the single fluorescent fusion proteins. These results suggest that the ratio of IκBα and p65 determine the kinetics of transcription factor translocation into the nucleus and indicate that the complex of p65 and IκBα is the true substrate for TNFα stimulation in mammalian cells. When cells were treated with the CRM-1-dependent nuclear export inhibitor,leptomycin B (LMB), there was nuclear accumulation of IκBα-EGFP and p65-dsRed, with IκBα-EGFP accumulating more rapidly. No NF-κB-dependent transcriptional activation was seen in response to LMB treatment. Following 1 hour treatment with LMB, significant IκBα-EGFP nuclear accumulation, but low levels of p65-dsRed nuclear accumulation, was observed. When these cells were stimulated with TNFα, degradation of IκBα-EGFP was observed in both the cytoplasm and nucleus. A normal transient transcription response was observed in the same cells using luminescence imaging of NF-κB-dependent transcription. These observations suggest that both normal activation and post-induction repression of NF-κB-dependent transcription occur even when nuclear export of NF-κB is inhibited. The results provide functional evidence that other factors, such as modification of p65 by phosphorylation, or interaction with other proteins such as transcriptional co-activators/co-repressors, may critically modulate the kinetics of transcription through this signalling pathway.

scholarly journals Correlative cryo super-resolution light and electron microscopy on mammalian cells using fluorescent proteins

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maarten W. Tuijtel ◽  
Abraham J. Koster ◽  
Stefan Jakobs ◽  
Frank G. A. Faas ◽  
Thomas H. Sharp
Keyword(s):  
Electron Microscopy ◽  
Mammalian Cells ◽  
Fluorescent Proteins ◽  
Light And Electron Microscopy ◽  
Super Resolution

scholarly journals A photoswitchable fluorescent protein for hours-time-lapse and sub-second-resolved super-resolution imaging

Microscopy ◽  
2021 ◽  
Author(s):  
Tetsuichi Wazawa ◽  
Ryohei Noma ◽  
Shusaku Uto ◽  
Kazunori Sugiura ◽  
Takashi Washio ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Ph Dependence ◽  
Super Resolution ◽  
Time Lapse ◽  
Light Irradiation ◽  
Acquisition Time ◽  
Polarization Angle ◽  
Cellular Dynamics

Abstract Reversibly photoswitchable fluorescent proteins (RSFPs) are a class of fluorescent proteins whose fluorescence can be turned on and off by light irradiation. RSFPs have become essential tools for super-resolution (SR) imaging. Because most SR imaging techniques require high-power-density illumination, mitigating phototoxicity in cells due to intense light irradiation has been a challenge. Although we previously developed an RSFP named Kohinoor to achieve SR imaging with low phototoxicity, the photoproperties were insufficient to move a step further to explore the cellular dynamics by SR imaging. Here, we show an improved version of RSFP, Kohinoor2.0, which is suitable for SR imaging of cellular processes. Kohinoor2.0 shows a 2.6-fold higher fluorescence intensity, 2.5-fold faster chromophore maturation and 1.5-fold faster off-switching than Kohinoor. The analysis of the pH dependence of the visible absorption band revealed that Kohinoor2.0 and Kohinoor were in equilibria among multiple fluorescently bright and dark states, with the mutations introduced into Kohinoor2.0 bringing about a higher stabilization of the fluorescently bright states compared to Kohinoor. Using Kohinoor2.0 with our SR imaging technique, super-resolution polarization demodulation/on-state polarization angle narrowing, we conducted 4-h time-lapse SR imaging of an actin filament network in mammalian cells with a total acquisition time of 480 s without a noticeable indication of phototoxicity. Furthermore, we demonstrated the SR imaging of mitochondria dynamics at a time resolution of 0.5 s, in which the fusion and fission processes were clearly visualized. Thus, Kohinoor2.0 is shown to be an invaluable RSFP for the SR imaging of cellular dynamics.

scholarly journals A Haploid Genetic Screening Method for Proteins Influencing Mammalian Nonsense-Mediated mRNA Decay Activity

2018 ◽  
Author(s):  
Maximilian W. Popp ◽  
Lynne E. Maquat
Keyword(s):  
Genetic Screening ◽  
Mammalian Cells ◽  
Mrna Decay ◽  
Fluorescent Proteins ◽  
Screening Method ◽  
Transcript Abundance ◽  
Exon Junction Complex ◽  
Exon Junction ◽  
Nonsense Mediated Mrna Decay

AbstractDespite a long appreciation for the role of nonsense-mediated mRNA decay (NMD) in the destruction of faulty, disease-causing mRNAs, as well as its role in the maintenance of normal, endogenous transcript abundance, systematic unbiased methods for uncovering modifiers of NMD activity in mammalian cells remain scant. Here we present and validate a haploid genetic screening method for identifying proteins and processes that stimulate NMD activity involving a 3′-untranslated region exon-junction complex. This reporterbased screening method can be adapted for interrogating other pathways whose output can be measured by the intracellular production of fluorescent proteins.

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