1
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Klemm C, Howell RSM, Thorpe PH. ScreenGarden: a shinyR application for fast and easy analysis of plate-based high-throughput screens. BMC Bioinformatics 2022; 23:60. [PMID: 35123390 PMCID: PMC8818250 DOI: 10.1186/s12859-022-04586-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 01/25/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Colony growth on solid media is a simple and effective measure for high-throughput genomic experiments such as yeast two-hybrid, synthetic dosage lethality and Synthetic Physical Interaction screens. The development of robotic pinning tools has facilitated the experimental design of these assays, and different imaging software can be used to automatically measure colony sizes on plates. However, comparison to control plates and statistical data analysis is often laborious and pinning issues or plate specific growth effects can lead to the detection of false-positive growth defects. RESULTS We have developed ScreenGarden, a shinyR application, to enable easy, quick and robust data analysis of plate-based high throughput assays. The code allows comparisons of different formats of data and different sized arrays of colonies. A comparison of ScreenGarden with previous analysis tools shows that it performs, at least, equivalently. The software can be run either via a website or offline via the RStudio program; the code is available and can be modified by expert uses to customise the analysis. CONCLUSIONS ScreenGarden provides a simple, fast and effective tool to analyse colony growth data from genomic experiments.
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Affiliation(s)
- Cinzia Klemm
- School of Biological and Behavioural Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Rowan S M Howell
- School of Biological and Behavioural Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.,UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Peter H Thorpe
- School of Biological and Behavioural Science, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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2
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Klemm C, Wood H, Thomas GH, Ólafsson G, Torres MT, Thorpe PH. Forced association of SARS-CoV-2 proteins with the yeast proteome perturb vesicle trafficking. MICROBIAL CELL (GRAZ, AUSTRIA) 2021; 8:280-296. [PMID: 34909432 PMCID: PMC8642885 DOI: 10.15698/mic2021.12.766] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/07/2021] [Accepted: 10/15/2021] [Indexed: 11/24/2022]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the highly infectious coronavirus disease COVID-19. Extensive research has been performed in recent months to better understand how SARS-CoV-2 infects and manipulates its host to identify potential drug targets and support patient recovery from COVID-19. However, the function of many SARS-CoV-2 proteins remains uncharacterised. Here we used the Synthetic Physical Interactions (SPI) method to recruit SARS-CoV-2 proteins to most of the budding yeast proteome to identify conserved pathways which are affected by SARS-CoV-2 proteins. The set of yeast proteins that result in growth defects when associated with the viral proteins have homologous functions that overlap those identified in studies performed in mammalian cells. Specifically, we were able to show that recruiting the SARS-CoV-2 NSP1 protein to HOPS, a vesicle-docking complex, is sufficient to perturb membrane trafficking in yeast consistent with the hijacking of the endoplasmic-reticulum-Golgi intermediate compartment trafficking pathway during viral infection of mammalian cells. These data demonstrate that the yeast SPI method is a rapid way to identify potential functions of ectopic viral proteins.
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Affiliation(s)
- Cinzia Klemm
- School of Biological and Behavioural Sciences, Queen Mary University of London, E1 4NS, UK
| | - Henry Wood
- School of Biological and Behavioural Sciences, Queen Mary University of London, E1 4NS, UK
| | - Grace Heredge Thomas
- School of Biological and Behavioural Sciences, Queen Mary University of London, E1 4NS, UK
| | - Guðjón Ólafsson
- School of Biological and Behavioural Sciences, Queen Mary University of London, E1 4NS, UK
- Institute for Systems Genetics, NYU Langone Health, New York, NY 10016, USA
| | - Mara Teixeira Torres
- School of Biological and Behavioural Sciences, Queen Mary University of London, E1 4NS, UK
| | - Peter H. Thorpe
- School of Biological and Behavioural Sciences, Queen Mary University of London, E1 4NS, UK
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3
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Mishra PK, Wood H, Stanton J, Au WC, Eisenstatt JR, Boeckmann L, Sclafani RA, Weinreich M, Bloom KS, Thorpe PH, Basrai MA. Cdc7-mediated phosphorylation of Cse4 regulates high-fidelity chromosome segregation in budding yeast. Mol Biol Cell 2021; 32:ar15. [PMID: 34432494 PMCID: PMC8693968 DOI: 10.1091/mbc.e21-06-0323] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/11/2021] [Accepted: 08/18/2021] [Indexed: 12/21/2022] Open
Abstract
Faithful chromosome segregation maintains chromosomal stability as errors in this process contribute to chromosomal instability (CIN), which has been observed in many diseases including cancer. Epigenetic regulation of kinetochore proteins such as Cse4 (CENP-A in humans) plays a critical role in high-fidelity chromosome segregation. Here we show that Cse4 is a substrate of evolutionarily conserved Cdc7 kinase, and that Cdc7-mediated phosphorylation of Cse4 prevents CIN. We determined that Cdc7 phosphorylates Cse4 in vitro and interacts with Cse4 in vivo in a cell cycle-dependent manner. Cdc7 is required for kinetochore integrity as reduced levels of CEN-associated Cse4, a faster exchange of Cse4 at the metaphase kinetochores, and defects in chromosome segregation, are observed in a cdc7-7 strain. Phosphorylation of Cse4 by Cdc7 is important for cell survival as constitutive association of a kinase-dead variant of Cdc7 (cdc7-kd) with Cse4 at the kinetochore leads to growth defects. Moreover, phospho-deficient mutations of Cse4 for consensus Cdc7 target sites contribute to CIN phenotype. In summary, our results have defined a role for Cdc7-mediated phosphorylation of Cse4 in faithful chromosome segregation.
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Affiliation(s)
- Prashant K. Mishra
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Henry Wood
- Queen Mary University of London, London E1 4NS, UK
| | - John Stanton
- University of North Carolina, Chapel Hill, NC 27599
| | - Wei-Chun Au
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Jessica R. Eisenstatt
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Lars Boeckmann
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | | | | | | | | | - Munira A. Basrai
- Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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4
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Smylla TK, Wagner K, Huber A. Application of Fluorescent Proteins for Functional Dissection of the Drosophila Visual System. Int J Mol Sci 2021; 22:8930. [PMID: 34445636 PMCID: PMC8396179 DOI: 10.3390/ijms22168930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/13/2021] [Accepted: 08/14/2021] [Indexed: 11/22/2022] Open
Abstract
The Drosophila eye has been used extensively to study numerous aspects of biological systems, for example, spatio-temporal regulation of differentiation, visual signal transduction, protein trafficking and neurodegeneration. Right from the advent of fluorescent proteins (FPs) near the end of the millennium, heterologously expressed fusion proteins comprising FPs have been applied in Drosophila vision research not only for subcellular localization of proteins but also for genetic screens and analysis of photoreceptor function. Here, we summarize applications for FPs used in the Drosophila eye as part of genetic screens, to study rhodopsin expression patterns, subcellular protein localization, membrane protein transport or as genetically encoded biosensors for Ca2+ and phospholipids in vivo. We also discuss recently developed FPs that are suitable for super-resolution or correlative light and electron microscopy (CLEM) approaches. Illustrating the possibilities provided by using FPs in Drosophila photoreceptors may aid research in other sensory or neuronal systems that have not yet been studied as well as the Drosophila eye.
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Affiliation(s)
- Thomas K. Smylla
- Department of Biochemistry, Institute of Biology, University of Hohenheim, 70599 Stuttgart, Germany; (K.W.); (A.H.)
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5
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Jayanthi B, Bachhav B, Wan Z, Martinez Legaspi S, Segatori L. A platform for post-translational spatiotemporal control of cellular proteins. Synth Biol (Oxf) 2021; 6:ysab002. [PMID: 33763602 PMCID: PMC7976946 DOI: 10.1093/synbio/ysab002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/31/2020] [Accepted: 01/06/2021] [Indexed: 12/11/2022] Open
Abstract
Mammalian cells process information through coordinated spatiotemporal regulation of proteins. Engineering cellular networks thus relies on efficient tools for regulating protein levels in specific subcellular compartments. To address the need to manipulate the extent and dynamics of protein localization, we developed a platform technology for the target-specific control of protein destination. This platform is based on bifunctional molecules comprising a target-specific nanobody and universal sequences determining target subcellular localization or degradation rate. We demonstrate that nanobody-mediated localization depends on the expression level of the target and the nanobody, and the extent of target subcellular localization can be regulated by combining multiple target-specific nanobodies with distinct localization or degradation sequences. We also show that this platform for nanobody-mediated target localization and degradation can be regulated transcriptionally and integrated within orthogonal genetic circuits to achieve the desired temporal control over spatial regulation of target proteins. The platform reported in this study provides an innovative tool to control protein subcellular localization, which will be useful to investigate protein function and regulate large synthetic gene circuits.
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Affiliation(s)
- Brianna Jayanthi
- Systems, Synthetic and Physical Biology Graduate Program, Rice University, Houston, TX, USA
| | - Bhagyashree Bachhav
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA
| | - Zengyi Wan
- Department of Bioengineering, Rice University, Houston, TX, USA
| | | | - Laura Segatori
- Systems, Synthetic and Physical Biology Graduate Program, Rice University, Houston, TX, USA
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA
- Department of Bioengineering, Rice University, Houston, TX, USA
- Department of Biosciences, Rice University, Houston, TX, USA
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6
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de Beer MA, Giepmans BNG. Nanobody-Based Probes for Subcellular Protein Identification and Visualization. Front Cell Neurosci 2020; 14:573278. [PMID: 33240044 PMCID: PMC7667270 DOI: 10.3389/fncel.2020.573278] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/05/2020] [Indexed: 12/14/2022] Open
Abstract
Understanding how building blocks of life contribute to physiology is greatly aided by protein identification and cellular localization. The two main labeling approaches developed over the past decades are labeling with antibodies such as immunoglobulin G (IgGs) or use of genetically encoded tags such as fluorescent proteins. However, IgGs are large proteins (150 kDa), which limits penetration depth and uncertainty of target position caused by up to ∼25 nm distance of the label created by the chosen targeting approach. Additionally, IgGs cannot be easily recombinantly modulated and engineered as part of fusion proteins because they consist of multiple independent translated chains. In the last decade single domain antigen binding proteins are being explored in bioscience as a tool in revealing molecular identity and localization to overcome limitations by IgGs. These nanobodies have several potential benefits over routine applications. Because of their small size (15 kDa), nanobodies better penetrate during labeling procedures and improve resolution. Moreover, nanobodies cDNA can easily be fused with other cDNA. Multidomain proteins can thus be easily engineered consisting of domains for targeting (nanobodies) and visualization by fluorescence microscopy (fluorescent proteins) or electron microscopy (based on certain enzymes). Additional modules for e.g., purification are also easily added. These nanobody-based probes can be applied in cells for live-cell endogenous protein detection or may be purified prior to use on molecules, cells or tissues. Here, we present the current state of nanobody-based probes and their implementation in microscopy, including pitfalls and potential future opportunities.
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Affiliation(s)
- Marit A de Beer
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Ben N G Giepmans
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
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7
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Ólafsson G, Thorpe PH. Polo kinase recruitment via the constitutive centromere-associated network at the kinetochore elevates centromeric RNA. PLoS Genet 2020; 16:e1008990. [PMID: 32810142 PMCID: PMC7455000 DOI: 10.1371/journal.pgen.1008990] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/28/2020] [Accepted: 07/13/2020] [Indexed: 12/23/2022] Open
Abstract
The kinetochore, a multi-protein complex assembled on centromeres, is essential to segregate chromosomes during cell division. Deficiencies in kinetochore function can lead to chromosomal instability and aneuploidy-a hallmark of cancer cells. Kinetochore function is controlled by recruitment of regulatory proteins, many of which have been documented, however their function often remains uncharacterized and many are yet to be identified. To identify candidates of kinetochore regulation we used a proteome-wide protein association strategy in budding yeast and detected many proteins that are involved in post-translational modifications such as kinases, phosphatases and histone modifiers. We focused on the Polo-like kinase, Cdc5, and interrogated which cellular components were sensitive to constitutive Cdc5 localization. The kinetochore is particularly sensitive to constitutive Cdc5 kinase activity. Targeting Cdc5 to different kinetochore subcomplexes produced diverse phenotypes, consistent with multiple distinct functions at the kinetochore. We show that targeting Cdc5 to the inner kinetochore, the constitutive centromere-associated network (CCAN), increases the levels of centromeric RNA via an SPT4 dependent mechanism.
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Affiliation(s)
- Guðjón Ólafsson
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom
| | - Peter H. Thorpe
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom
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8
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Howell RSM, Csikász-Nagy A, Thorpe PH. Synthetic Physical Interactions with the Yeast Centrosome. G3 (BETHESDA, MD.) 2019; 9:2183-2194. [PMID: 31076383 PMCID: PMC6643875 DOI: 10.1534/g3.119.400117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/02/2019] [Indexed: 12/30/2022]
Abstract
The yeast centrosome or Spindle Pole Body (SPB) is an organelle situated in the nuclear membrane, where it nucleates spindle microtubules and acts as a signaling hub. Various studies have explored the effects of forcing individual proteins to interact with the yeast SPB, however no systematic study has been performed. We used synthetic physical interactions to detect proteins that inhibit growth when forced to associate with the SPB. We found the SPB to be especially sensitive to relocalization, necessitating a novel data analysis approach. This novel analysis of SPI screening data shows that regions of the cell are locally more sensitive to forced relocalization than previously thought. Furthermore, we found a set of associations that result in elevated SPB number and, in some cases, multi-polar spindles. Since hyper-proliferation of centrosomes is a hallmark of cancer cells, these associations point the way for the use of yeast models in the study of spindle formation and chromosome segregation in cancer.
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Affiliation(s)
- Rowan S M Howell
- The Francis Crick Institute, London, NW1 1AT UK
- Randall Division of Cell and Molecular Biophysics, King's College, London, SE1 1UL UK
| | - Attila Csikász-Nagy
- Randall Division of Cell and Molecular Biophysics, King's College, London, SE1 1UL UK
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, 1083 Hungary
| | - Peter H Thorpe
- School of Biological and Chemical Sciences, Queen Mary University, London, E1 4NS UK
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9
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Harmansa S, Affolter M. Protein binders and their applications in developmental biology. Development 2018; 145:145/2/dev148874. [PMID: 29374062 DOI: 10.1242/dev.148874] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Developmental biology research would benefit greatly from tools that enable protein function to be regulated, both systematically and in a precise spatial and temporal manner, in vivo In recent years, functionalized protein binders have emerged as versatile tools that can be used to target and manipulate proteins. Such protein binders can be based on various scaffolds, such as nanobodies, designed ankyrin repeat proteins (DARPins) and monobodies, and can be used to block or perturb protein function in living cells. In this Primer, we provide an overview of the protein binders that are currently available and highlight recent progress made in applying protein binder-based tools in developmental and synthetic biology.
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Affiliation(s)
- Stefan Harmansa
- Growth and Development, Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Markus Affolter
- Growth and Development, Biozentrum, University of Basel, 4056 Basel, Switzerland
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10
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Roggenkamp E, Giersch RM, Wedeman E, Eaton M, Turnquist E, Schrock MN, Alkotami L, Jirakittisonthon T, Schluter-Pascua SE, Bayne GH, Wasko C, Halloran M, Finnigan GC. CRISPR-UnLOCK: Multipurpose Cas9-Based Strategies for Conversion of Yeast Libraries and Strains. Front Microbiol 2017; 8:1773. [PMID: 28979241 PMCID: PMC5611381 DOI: 10.3389/fmicb.2017.01773] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 08/31/2017] [Indexed: 11/29/2022] Open
Abstract
Saccharomyces cerevisiae continues to serve as a powerful model system for both basic biological research and industrial application. The development of genome-wide collections of individually manipulated strains (libraries) has allowed for high-throughput genetic screens and an emerging global view of this single-celled Eukaryote. The success of strain construction has relied on the innate ability of budding yeast to accept foreign DNA and perform homologous recombination, allowing for efficient plasmid construction (in vivo) and integration of desired sequences into the genome. The development of molecular toolkits and “integration cassettes” have provided fungal systems with a collection of strategies for tagging, deleting, or over-expressing target genes; typically, these consist of a C-terminal tag (epitope or fluorescent protein), a universal terminator sequence, and a selectable marker cassette to allow for convenient screening. However, there are logistical and technical obstacles to using these traditional genetic modules for complex strain construction (manipulation of many genomic targets in a single cell) or for the generation of entire genome-wide libraries. The recent introduction of the CRISPR/Cas gene editing technology has provided a powerful methodology for multiplexed editing in many biological systems including yeast. We have developed four distinct uses of the CRISPR biotechnology to generate yeast strains that utilizes the conversion of existing, commonly-used yeast libraries or strains. We present Cas9-based, marker-less methodologies for (i) N-terminal tagging, (ii) C-terminally tagging yeast genes with 18 unique fusions, (iii) conversion of fluorescently-tagged strains into newly engineered (or codon optimized) variants, and finally, (iv) use of a Cas9 “gene drive” system to rapidly achieve a homozygous state for a hypomorphic query allele in a diploid strain. These CRISPR-based methods demonstrate use of targeting universal sequences previously introduced into a genome.
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Affiliation(s)
- Emily Roggenkamp
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Rachael M Giersch
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Emily Wedeman
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Muriel Eaton
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Emily Turnquist
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Madison N Schrock
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Linah Alkotami
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Thitikan Jirakittisonthon
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State UniversityManhattan, KS, United States
| | | | - Gareth H Bayne
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Cory Wasko
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Megan Halloran
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Gregory C Finnigan
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
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11
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Traenkle B, Rothbauer U. Under the Microscope: Single-Domain Antibodies for Live-Cell Imaging and Super-Resolution Microscopy. Front Immunol 2017; 8:1030. [PMID: 28883823 PMCID: PMC5573807 DOI: 10.3389/fimmu.2017.01030] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 08/09/2017] [Indexed: 12/12/2022] Open
Abstract
Single-domain antibodies (sdAbs) have substantially expanded the possibilities of advanced cellular imaging such as live-cell or super-resolution microscopy to visualize cellular antigens and their dynamics. In addition to their unique properties including small size, high stability, and solubility in many environments, sdAbs can be efficiently functionalized according to the needs of the respective imaging approach. Genetically encoded intrabodies fused to fluorescent proteins (chromobodies) have become versatile tools to study dynamics of endogenous proteins in living cells. Additionally, sdAbs conjugated to organic dyes were shown to label cellular structures with high density and minimal fluorophore displacement making them highly attractive probes for super-resolution microscopy. Here, we review recent advances of the chromobody technology to visualize localization and dynamics of cellular targets and the application of chromobody-based cell models for compound screening. Acknowledging the emerging importance of super-resolution microscopy in cell biology, we further discuss advantages and challenges of sdAbs for this technology.
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Affiliation(s)
- Bjoern Traenkle
- Pharmaceutical Biotechnology, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Ulrich Rothbauer
- Pharmaceutical Biotechnology, Eberhard Karls University Tuebingen, Tuebingen, Germany.,Natural and Medical Sciences Institute at the University of Tuebingen, Reutlingen, Germany
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12
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Harmansa S, Alborelli I, Bieli D, Caussinus E, Affolter M. A nanobody-based toolset to investigate the role of protein localization and dispersal in Drosophila. eLife 2017; 6. [PMID: 28395731 PMCID: PMC5388529 DOI: 10.7554/elife.22549] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 03/14/2017] [Indexed: 12/26/2022] Open
Abstract
The role of protein localization along the apical-basal axis of polarized cells is difficult to investigate in vivo, partially due to lack of suitable tools. Here, we present the GrabFP system, a collection of four nanobody-based GFP-traps that localize to defined positions along the apical-basal axis. We show that the localization preference of the GrabFP traps can impose a novel localization on GFP-tagged target proteins and results in their controlled mislocalization. These new tools were used to mislocalize transmembrane and cytoplasmic GFP fusion proteins in the Drosophila wing disc epithelium and to investigate the effect of protein mislocalization. Furthermore, we used the GrabFP system as a tool to study the extracellular dispersal of the Decapentaplegic (Dpp) protein and show that the Dpp gradient forming in the lateral plane of the Drosophila wing disc epithelium is essential for patterning of the wing imaginal disc.
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Affiliation(s)
- Stefan Harmansa
- Growth and Development, Biozentrum, University of Basel, Basel, Switzerland
| | - Ilaria Alborelli
- Growth and Development, Biozentrum, University of Basel, Basel, Switzerland
| | - Dimitri Bieli
- Growth and Development, Biozentrum, University of Basel, Basel, Switzerland
| | - Emmanuel Caussinus
- Growth and Development, Biozentrum, University of Basel, Basel, Switzerland.,Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Markus Affolter
- Growth and Development, Biozentrum, University of Basel, Basel, Switzerland
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13
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Abstract
The spindle assembly checkpoint (SAC) is a key mechanism to regulate the timing of mitosis and ensure that chromosomes are correctly segregated to daughter cells. The recruitment of the Mad1 and Mad2 proteins to the kinetochore is normally necessary for SAC activation. This recruitment is coordinated by the SAC kinase Mps1, which phosphorylates residues at the kinetochore to facilitate binding of Bub1, Bub3, Mad1, and Mad2. There is evidence that the essential function of Mps1 is to direct recruitment of Mad1/2. To test this model, we have systematically recruited Mad1, Mad2, and Mps1 to most proteins in the yeast kinetochore, and find that, while Mps1 is sufficient for checkpoint activation, recruitment of either Mad1 or Mad2 is not. These data indicate an important role for Mps1 phosphorylation in SAC activation, beyond the direct recruitment of Mad1 and Mad2.
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