1
|
Olivares-Abril J, Joha J, Lee JY, Davis I. Optimization of hybridization chain reaction for imaging single RNA molecules in Drosophila larvae. Fly (Austin) 2024; 18:2409968. [PMID: 39351922 PMCID: PMC11446410 DOI: 10.1080/19336934.2024.2409968] [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: 06/06/2024] [Revised: 09/23/2024] [Accepted: 09/23/2024] [Indexed: 10/03/2024] Open
Abstract
In situ hybridization techniques are powerful methods for exploring gene expression in a wide range of biological contexts, providing spatial information that is most often lost in traditional biochemical techniques. However, many in situ hybridization methods are costly and time-inefficient, particularly for screening-based projects that follow on from single-cell RNA sequencing data, which rely on of tens of custom-synthetized probes against each specific RNA of interest. Here we provide an optimized pipeline for Hybridization Chain Reaction (HCR)-based RNA visualization, including an open-source code for optimized probe design. Our method achieves high specificity and sensitivity with the option of multiplexing using only five pairs of probes, which greatly lowers the cost and time of the experiment. These features of our HCR protocol are particularly useful and convenient for projects involving screening several genes at medium throughput, especially as the method include an amplification step, which makes the signal readily visible at low magnification imaging.
Collapse
Affiliation(s)
| | - Jana Joha
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Jeffrey Y Lee
- School of Molecular Biosciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Ilan Davis
- School of Molecular Biosciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| |
Collapse
|
2
|
Lee JY, Gala DS, Kiourlappou M, Olivares-Abril J, Joha J, Titlow JS, Teodoro RO, Davis I. Murine glial protrusion transcripts predict localized Drosophila glial mRNAs involved in plasticity. J Cell Biol 2024; 223:e202306152. [PMID: 39037431 PMCID: PMC11262410 DOI: 10.1083/jcb.202306152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 06/14/2024] [Accepted: 07/03/2024] [Indexed: 07/23/2024] Open
Abstract
The polarization of cells often involves the transport of specific mRNAs and their localized translation in distal projections. Neurons and glia are both known to contain long cytoplasmic processes, while localized transcripts have only been studied extensively in neurons, not glia, especially in intact nervous systems. Here, we predict 1,740 localized Drosophila glial transcripts by extrapolating from our meta-analysis of seven existing studies characterizing the localized transcriptomes and translatomes of synaptically associated mammalian glia. We demonstrate that the localization of mRNAs in mammalian glial projections strongly predicts the localization of their high-confidence Drosophila homologs in larval motor neuron-associated glial projections and are highly statistically enriched for genes associated with neurological diseases. We further show that some of these localized glial transcripts are specifically required in glia for structural plasticity at the nearby neuromuscular junction synapses. We conclude that peripheral glial mRNA localization is a common and conserved phenomenon and propose that it is likely to be functionally important in disease.
Collapse
Affiliation(s)
- Jeffrey Y. Lee
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Dalia S. Gala
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | | | - Jana Joha
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Rita O. Teodoro
- iNOVA4Health, NOVA Medical School | Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Ilan Davis
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Department of Biochemistry, University of Oxford, Oxford, UK
| |
Collapse
|
3
|
Titlow JS, Kiourlappou M, Palanca A, Lee JY, Gala DS, Ennis D, Yu JJ, Young FL, Susano Pinto DM, Garforth S, Francis HS, Strivens F, Mulvey H, Dallman-Porter A, Thornton S, Arman D, Millard MJ, Järvelin AI, Thompson MK, Sargent M, Kounatidis I, Parton RM, Taylor S, Davis I. Systematic analysis of YFP traps reveals common mRNA/protein discordance in neural tissues. J Cell Biol 2023; 222:e202205129. [PMID: 37145332 PMCID: PMC10165541 DOI: 10.1083/jcb.202205129] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 11/11/2022] [Accepted: 12/06/2022] [Indexed: 05/06/2023] Open
Abstract
While post-transcriptional control is thought to be required at the periphery of neurons and glia, its extent is unclear. Here, we investigate systematically the spatial distribution and expression of mRNA at single molecule sensitivity and their corresponding proteins of 200 YFP trap lines across the intact Drosophila nervous system. 97.5% of the genes studied showed discordance between the distribution of mRNA and the proteins they encode in at least one region of the nervous system. These data suggest that post-transcriptional regulation is very common, helping to explain the complexity of the nervous system. We also discovered that 68.5% of these genes have transcripts present at the periphery of neurons, with 9.5% at the glial periphery. Peripheral transcripts include many potential new regulators of neurons, glia, and their interactions. Our approach is applicable to most genes and tissues and includes powerful novel data annotation and visualization tools for post-transcriptional regulation.
Collapse
Affiliation(s)
| | | | - Ana Palanca
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Jeffrey Y. Lee
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Dalia S. Gala
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Darragh Ennis
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Joyce J.S. Yu
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | | | - Sam Garforth
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Finn Strivens
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Hugh Mulvey
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Staci Thornton
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Diana Arman
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | | | | | - Martin Sargent
- Weatherall Institute for Molecular Medicine, University of Oxford, Oxford, UK
| | | | | | - Stephen Taylor
- Weatherall Institute for Molecular Medicine, University of Oxford, Oxford, UK
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford, UK
| |
Collapse
|
4
|
Gala DS, Titlow JS, Teodoro RO, Davis I. Far from home: the role of glial mRNA localization in synaptic plasticity. RNA (NEW YORK, N.Y.) 2023; 29:153-169. [PMID: 36442969 PMCID: PMC9891262 DOI: 10.1261/rna.079422.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Neurons and glia are highly polarized cells, whose distal cytoplasmic functional subdomains require specific proteins. Neurons have axonal and dendritic cytoplasmic extensions containing synapses whose plasticity is regulated efficiently by mRNA transport and localized translation. The principles behind these mechanisms are equally attractive for explaining rapid local regulation of distal glial cytoplasmic projections, independent of their cell nucleus. However, in contrast to neurons, mRNA localization has received little experimental attention in glia. Nevertheless, there are many functionally diverse glial subtypes containing extensive networks of long cytoplasmic projections with likely localized regulation that influence neurons and their synapses. Moreover, glia have many other neuron-like properties, including electrical activity, secretion of gliotransmitters and calcium signaling, influencing, for example, synaptic transmission, plasticity and axon pruning. Here, we review previous studies concerning glial transcripts with important roles in influencing synaptic plasticity, focusing on a few cases involving localized translation. We discuss a variety of important questions about mRNA transport and localized translation in glia that remain to be addressed, using cutting-edge tools already available for neurons.
Collapse
Affiliation(s)
- Dalia S Gala
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Joshua S Titlow
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Rita O Teodoro
- iNOVA4Health, NOVA Medical School-Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa 1169-056, Portugal
| | - Ilan Davis
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
| |
Collapse
|
5
|
Christopher JA, Geladaki A, Dawson CS, Vennard OL, Lilley KS. Subcellular Transcriptomics and Proteomics: A Comparative Methods Review. Mol Cell Proteomics 2022; 21:100186. [PMID: 34922010 PMCID: PMC8864473 DOI: 10.1016/j.mcpro.2021.100186] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 11/16/2021] [Accepted: 12/13/2021] [Indexed: 12/23/2022] Open
Abstract
The internal environment of cells is molecularly crowded, which requires spatial organization via subcellular compartmentalization. These compartments harbor specific conditions for molecules to perform their biological functions, such as coordination of the cell cycle, cell survival, and growth. This compartmentalization is also not static, with molecules trafficking between these subcellular neighborhoods to carry out their functions. For example, some biomolecules are multifunctional, requiring an environment with differing conditions or interacting partners, and others traffic to export such molecules. Aberrant localization of proteins or RNA species has been linked to many pathological conditions, such as neurological, cancer, and pulmonary diseases. Differential expression studies in transcriptomics and proteomics are relatively common, but the majority have overlooked the importance of subcellular information. In addition, subcellular transcriptomics and proteomics data do not always colocate because of the biochemical processes that occur during and after translation, highlighting the complementary nature of these fields. In this review, we discuss and directly compare the current methods in spatial proteomics and transcriptomics, which include sequencing- and imaging-based strategies, to give the reader an overview of the current tools available. We also discuss current limitations of these strategies as well as future developments in the field of spatial -omics.
Collapse
Affiliation(s)
- Josie A Christopher
- Department of Biochemistry, Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Cambridge, UK
| | - Aikaterini Geladaki
- Department of Biochemistry, Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK; Department of Genetics, University of Cambridge, Cambridge, UK
| | - Charlotte S Dawson
- Department of Biochemistry, Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Cambridge, UK
| | - Owen L Vennard
- Department of Biochemistry, Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Cambridge, UK
| | - Kathryn S Lilley
- Department of Biochemistry, Cambridge Centre for Proteomics, University of Cambridge, Cambridge, UK; Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, Cambridge, UK.
| |
Collapse
|
6
|
Lee JY, Wing PAC, Gala DS, Noerenberg M, Järvelin AI, Titlow J, Zhuang X, Palmalux N, Iselin L, Thompson MK, Parton RM, Prange-Barczynska M, Wainman A, Salguero FJ, Bishop T, Agranoff D, James W, Castello A, McKeating JA, Davis I. Absolute quantitation of individual SARS-CoV-2 RNA molecules provides a new paradigm for infection dynamics and variant differences. eLife 2022; 11:74153. [PMID: 35049501 PMCID: PMC8776252 DOI: 10.7554/elife.74153] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 12/21/2021] [Indexed: 12/11/2022] Open
Abstract
Despite an unprecedented global research effort on SARS-CoV-2, early replication events remain poorly understood. Given the clinical importance of emergent viral variants with increased transmission, there is an urgent need to understand the early stages of viral replication and transcription. We used single-molecule fluorescence in situ hybridisation (smFISH) to quantify positive sense RNA genomes with 95% detection efficiency, while simultaneously visualising negative sense genomes, subgenomic RNAs, and viral proteins. Our absolute quantification of viral RNAs and replication factories revealed that SARS-CoV-2 genomic RNA is long-lived after entry, suggesting that it avoids degradation by cellular nucleases. Moreover, we observed that SARS-CoV-2 replication is highly variable between cells, with only a small cell population displaying high burden of viral RNA. Unexpectedly, the B.1.1.7 variant, first identified in the UK, exhibits significantly slower replication kinetics than the Victoria strain, suggesting a novel mechanism contributing to its higher transmissibility with important clinical implications.
Collapse
Affiliation(s)
- Jeffrey Y Lee
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Peter AC Wing
- Nuffield Department of Medicine, The University of OxfordOxfordUnited Kingdom,Chinese Academy of Medical Sciences (CAMS) Oxford Institute (COI), The University of OxfordOxfordUnited Kingdom
| | - Dalia S Gala
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Marko Noerenberg
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom,MRC-University of Glasgow Centre for Virus Research, The University of GlasgowGlasgowUnited Kingdom
| | - Aino I Järvelin
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Joshua Titlow
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Xiaodong Zhuang
- Nuffield Department of Medicine, The University of OxfordOxfordUnited Kingdom
| | - Natasha Palmalux
- MRC-University of Glasgow Centre for Virus Research, The University of GlasgowGlasgowUnited Kingdom
| | - Louisa Iselin
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Mary Kay Thompson
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Richard M Parton
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| | - Maria Prange-Barczynska
- Nuffield Department of Medicine, The University of OxfordOxfordUnited Kingdom,Ludwig Institute for Cancer Research, The University of OxfordOxfordUnited Kingdom
| | - Alan Wainman
- Sir William Dunn School of Pathology, The University of OxfordOxfordUnited Kingdom
| | | | - Tammie Bishop
- Nuffield Department of Medicine, The University of OxfordOxfordUnited Kingdom,Ludwig Institute for Cancer Research, The University of OxfordOxfordUnited Kingdom
| | - Daniel Agranoff
- Department of Infectious Diseases, University Hospitals Sussex NHS Foundation TrustBrightonUnited Kingdom
| | - William James
- Sir William Dunn School of Pathology, The University of OxfordOxfordUnited Kingdom,James & Lillian Martin Centre, Sir William Dunn School of Pathology, The University of OxfordOxfordUnited Kingdom
| | - Alfredo Castello
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom,MRC-University of Glasgow Centre for Virus Research, The University of GlasgowGlasgowUnited Kingdom
| | - Jane A McKeating
- Nuffield Department of Medicine, The University of OxfordOxfordUnited Kingdom,Chinese Academy of Medical Sciences (CAMS) Oxford Institute (COI), The University of OxfordOxfordUnited Kingdom
| | - Ilan Davis
- Department of Biochemistry, The University of OxfordOxfordUnited Kingdom
| |
Collapse
|
7
|
Auer JMT, Stoddart JJ, Christodoulou I, Lima A, Skouloudaki K, Hall HN, Vukojević V, Papadopoulos DK. Of numbers and movement - understanding transcription factor pathogenesis by advanced microscopy. Dis Model Mech 2020; 13:dmm046516. [PMID: 33433399 PMCID: PMC7790199 DOI: 10.1242/dmm.046516] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Transcription factors (TFs) are life-sustaining and, therefore, the subject of intensive research. By regulating gene expression, TFs control a plethora of developmental and physiological processes, and their abnormal function commonly leads to various developmental defects and diseases in humans. Normal TF function often depends on gene dosage, which can be altered by copy-number variation or loss-of-function mutations. This explains why TF haploinsufficiency (HI) can lead to disease. Since aberrant TF numbers frequently result in pathogenic abnormalities of gene expression, quantitative analyses of TFs are a priority in the field. In vitro single-molecule methodologies have significantly aided the identification of links between TF gene dosage and transcriptional outcomes. Additionally, advances in quantitative microscopy have contributed mechanistic insights into normal and aberrant TF function. However, to understand TF biology, TF-chromatin interactions must be characterised in vivo, in a tissue-specific manner and in the context of both normal and altered TF numbers. Here, we summarise the advanced microscopy methodologies most frequently used to link TF abundance to function and dissect the molecular mechanisms underlying TF HIs. Increased application of advanced single-molecule and super-resolution microscopy modalities will improve our understanding of how TF HIs drive disease.
Collapse
Affiliation(s)
- Julia M T Auer
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 1XU, UK
| | - Jack J Stoddart
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 1XU, UK
| | | | - Ana Lima
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 1XU, UK
| | | | - Hildegard N Hall
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 1XU, UK
| | - Vladana Vukojević
- Center for Molecular Medicine (CMM), Department of Clinical Neuroscience, Karolinska Institutet, 17176 Stockholm, Sweden
| | | |
Collapse
|
8
|
Titlow J, Robertson F, Järvelin A, Ish-Horowicz D, Smith C, Gratton E, Davis I. Syncrip/hnRNP Q is required for activity-induced Msp300/Nesprin-1 expression and new synapse formation. J Cell Biol 2020; 219:133707. [PMID: 32040548 PMCID: PMC7055005 DOI: 10.1083/jcb.201903135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 08/21/2019] [Accepted: 12/12/2019] [Indexed: 01/09/2023] Open
Abstract
Memory and learning involve activity-driven expression of proteins and cytoskeletal reorganization at new synapses, requiring posttranscriptional regulation of localized mRNA a long distance from corresponding nuclei. A key factor expressed early in synapse formation is Msp300/Nesprin-1, which organizes actin filaments around the new synapse. How Msp300 expression is regulated during synaptic plasticity is poorly understood. Here, we show that activity-dependent accumulation of Msp300 in the postsynaptic compartment of the Drosophila larval neuromuscular junction is regulated by the conserved RNA binding protein Syncrip/hnRNP Q. Syncrip (Syp) binds to msp300 transcripts and is essential for plasticity. Single-molecule imaging shows that msp300 is associated with Syp in vivo and forms ribosome-rich granules that contain the translation factor eIF4E. Elevated neural activity alters the dynamics of Syp and the number of msp300:Syp:eIF4E RNP granules at the synapse, suggesting that these particles facilitate translation. These results introduce Syp as an important early acting activity-dependent regulator of a plasticity gene that is strongly associated with human ataxias.
Collapse
Affiliation(s)
- Joshua Titlow
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Aino Järvelin
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - David Ish-Horowicz
- Department of Biochemistry, University of Oxford, Oxford, UK.,Medical Research Council Lab for Molecular Cell Biology, University College London, London, UK
| | - Carlas Smith
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, UK
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, University of California Irvine, Irvine, CA
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, Oxford, UK
| |
Collapse
|
9
|
Badawi Y, Nishimune H. Super-resolution microscopy for analyzing neuromuscular junctions and synapses. Neurosci Lett 2020; 715:134644. [PMID: 31765730 PMCID: PMC6937598 DOI: 10.1016/j.neulet.2019.134644] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 12/12/2022]
Abstract
Super-resolution microscopy techniques offer subdiffraction limited resolution that is two- to ten-fold improved compared to that offered by conventional confocal microscopy. This breakthrough in resolution for light microscopy has contributed to new findings in neuroscience and synapse biology. This review will focus on the Structured Illumination Microscopy (SIM), Stimulated emission depletion (STED) microscopy, and Stochastic optical reconstruction microscopy (STORM) / Single molecule localization microscopy (SMLM) techniques and compare them for the better understanding of their differences and their suitability for the analysis of synapse biology. In addition, we will discuss a few practical aspects of these microscopic techniques, including resolution, image acquisition speed, multicolor capability, and other advantages and disadvantages. Tips for the improvement of microscopy will be introduced; for example, information resources for recommended dyes, the limitations of multicolor analysis, and capabilities for live imaging. In addition, we will summarize how super-resolution microscopy has been used for analyses of neuromuscular junctions and synapses.
Collapse
Affiliation(s)
- Yomna Badawi
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, KS, 66160, USA
| | - Hiroshi Nishimune
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, KS, 66160, USA.
| |
Collapse
|
10
|
Wirth R, Gao P, Nienhaus GU, Sunbul M, Jäschke A. SiRA: A Silicon Rhodamine-Binding Aptamer for Live-Cell Super-Resolution RNA Imaging. J Am Chem Soc 2019; 141:7562-7571. [PMID: 30986047 DOI: 10.1021/jacs.9b02697] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although genetically encoded light-up RNA aptamers have become promising tools for visualizing and tracking RNAs in living cells, aptamer/ligand pairs that emit in the far-red and near-infrared (NIR) regions are still rare. In this work, we developed a light-up RNA aptamer that binds silicon rhodamines (SiRs). SiRs are photostable, NIR-emitting fluorophores that change their open-closed equilibrium between the noncolored spirolactone and the fluorescent zwitterion in response to their environment. This property is responsible for their high cell permeability and fluorogenic behavior. Aptamers binding to SiR were in vitro selected from a combinatorial RNA library. Sequencing, bioinformatic analysis, truncation, and mutational studies revealed a 50-nucleotide minimal aptamer, SiRA, which binds with nanomolar affinity to the target SiR. In addition to silicon rhodamines, SiRA binds structurally related rhodamines and carborhodamines, making it a versatile tool spanning the far-red region of the spectrum. Photophysical characterization showed that SiRA is remarkably resistant to photobleaching and constitutes the brightest far-red light-up aptamer system known to date owing to its favorable features: a fluorescence quantum yield of 0.98 and an extinction coefficient of 86 000 M-1cm-1. Using the SiRA system, we visualized the expression of RNAs in bacteria in no-wash live-cell imaging experiments and also report stimulated emission depletion (STED) super-resolution microscopy images of aptamer-based, fluorescently labeled mRNA in live cells. This work represents, to our knowledge, the first application of the popular SiR dyes and of intramolecular spirocyclization as a means of background reduction in the field of aptamer-based RNA imaging. We anticipate a high potential for this novel RNA labeling tool to address biological questions.
Collapse
Affiliation(s)
- Regina Wirth
- Institute of Pharmacy and Molecular Biotechnology (IPMB) , Heidelberg University , 69120 Heidelberg , Germany
| | - Peng Gao
- Institute of Applied Physics (APH) , Karlsruhe Institute of Technology (KIT) , Wolfgang-Gaede-Straße 1 , D-76131 Karlsruhe , Germany.,Institute of Nanotechnology (INT) , Karlsruhe Institute of Technology (KIT) , D-76344 Eggenstein-Leopoldshafen , Germany
| | - G Ulrich Nienhaus
- Institute of Applied Physics (APH) , Karlsruhe Institute of Technology (KIT) , Wolfgang-Gaede-Straße 1 , D-76131 Karlsruhe , Germany.,Institute of Nanotechnology (INT) , Karlsruhe Institute of Technology (KIT) , D-76344 Eggenstein-Leopoldshafen , Germany.,Institute of Toxicology and Genetics (ITG) , Karlsruhe Institute of Technology (KIT) , D-76344 Eggenstein-Leopoldshafen , Germany.,Department of Physics , University of Illinois at Urbana-Champaign , 1110 West Green Street , Urbana , Illinois 61801 , United States
| | - Murat Sunbul
- Institute of Pharmacy and Molecular Biotechnology (IPMB) , Heidelberg University , 69120 Heidelberg , Germany
| | - Andres Jäschke
- Institute of Pharmacy and Molecular Biotechnology (IPMB) , Heidelberg University , 69120 Heidelberg , Germany
| |
Collapse
|
11
|
Hughes SC, Simmonds AJ. Drosophila mRNA Localization During Later Development: Past, Present, and Future. Front Genet 2019; 10:135. [PMID: 30899273 PMCID: PMC6416162 DOI: 10.3389/fgene.2019.00135] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 02/11/2019] [Indexed: 12/12/2022] Open
Abstract
Multiple mechanisms tightly regulate mRNAs during their transcription, translation, and degradation. Of these, the physical localization of mRNAs to specific cytoplasmic regions is relatively easy to detect; however, linking localization to functional regulatory roles has been more difficult to establish. Historically, Drosophila melanogaster is a highly effective model to identify localized mRNAs and has helped identify roles for this process by regulating various cell activities. The majority of the well-characterized functional roles for localizing mRNAs to sub-regions of the cytoplasm have come from the Drosophila oocyte and early syncytial embryo. At present, relatively few functional roles have been established for mRNA localization within the relatively smaller, differentiated somatic cell lineages characteristic of later development, beginning with the cellular blastoderm, and the multiple cell lineages that make up the gastrulating embryo, larva, and adult. This review is divided into three parts—the first outlines past evidence for cytoplasmic mRNA localization affecting aspects of cellular activity post-blastoderm development in Drosophila. The majority of these known examples come from highly polarized cell lineages such as differentiating neurons. The second part considers the present state of affairs where we now know that many, if not most mRNAs are localized to discrete cytoplasmic regions in one or more somatic cell lineages of cellularized embryos, larvae or adults. Assuming that the phenomenon of cytoplasmic mRNA localization represents an underlying functional activity, and correlation with the encoded proteins suggests that mRNA localization is involved in far more than neuronal differentiation. Thus, it seems highly likely that past-identified examples represent only a small fraction of localization-based mRNA regulation in somatic cells. The last part highlights recent technological advances that now provide an opportunity for probing the role of mRNA localization in Drosophila, moving beyond cataloging the diversity of localized mRNAs to a similar understanding of how localization affects mRNA activity.
Collapse
Affiliation(s)
- Sarah C Hughes
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Andrew J Simmonds
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
12
|
Blice-Baum AC, Vogler G, Viswanathan MC, Trinh B, Limpitikul WB, Cammarato A. Quantifying Tissue-Specific Overexpression of FOXO in Drosophila via mRNA Fluorescence In Situ Hybridization Using Branched DNA Probe Technology. Methods Mol Biol 2019; 1890:171-190. [PMID: 30414154 PMCID: PMC7906431 DOI: 10.1007/978-1-4939-8900-3_15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
While the highly conserved FOXO transcription factors have been studied in Drosophila melanogaster for decades, the ability to accurately control and measure their tissue-specific expression is often cumbersome due to a lack of reagents and to limited, nonhomogeneous samples. The need for quantitation within a distinct cell type is particularly important because transcription factors must be expressed in specific amounts to perform their functions properly. However, the inherent heterogeneity of many samples can make evaluating cell-specific FOXO and/or FOXO load difficult. Here, we describe an extremely sensitive fluorescence in situ hybridization (FISH) approach for visualizing and quantifying multiple mRNAs with single-cell resolution in adult Drosophila cardiomyocytes. The procedure relies upon branched DNA technology, which allows several fluorescent molecules to label an individual transcript, drastically increasing the signal-to-noise ratio compared to other FISH assays. This protocol can be modified for use in various small animal models, tissue types, and for assorted nucleic acids.
Collapse
Affiliation(s)
- Anna C Blice-Baum
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Science Department, Iadarola Center for Science, Education and Technology, Cabrini University, Radnor, PA, USA.
| | - Georg Vogler
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
| | - Meera C Viswanathan
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Bosco Trinh
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Worawan B Limpitikul
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
13
|
Noma A, Smith CS, Huisman M, Martin RM, Moore MJ, Grunwald D. Advanced 3D Analysis and Optimization of Single-Molecule FISH in Drosophila Muscle. SMALL METHODS 2018; 2:1700324. [PMID: 32158910 PMCID: PMC7063683 DOI: 10.1002/smtd.201700324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Indexed: 06/10/2023]
Abstract
Single-molecule fluorescence in situ hybridization (smFISH) provides direct access to the spatial relationship between nucleic acids and specific subcellular locations. The ability to precisely localize a messenger RNA can reveal key information about its regulation. Although smFISH is well established in cell culture or thin sections, the utility of smFISH is hindered in thick tissue sections due to the poor probe penetration of fixed tissue, the inaccessibility of target mRNAs for probe hybridization, high background fluorescence, spherical aberration along the optical axis, and the lack of methods for image segmentation of organelles. Studying mRNA localization in 50 μm thick Drosophila larval muscle sections, these obstacles are overcome using sample-specific optimization of smFISH, particle identification based on maximum likelihood testing, and 3D multiple-organelle segmentation. The latter allows independent thresholds to be assigned to different regions of interest within an image stack. This approach therefore facilitates accurate measurement of mRNA location in thick tissues.
Collapse
Affiliation(s)
- Akiko Noma
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Carlas S Smith
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Maximiliaan Huisman
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Robert M Martin
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1600-276 Lisboa, Portugal
| | - Melissa J Moore
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - David Grunwald
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| |
Collapse
|
14
|
Pasnuri N, Khuntia P, Mazumder A. Single transcript imaging to assay gene expression in wholemount Drosophila melanogaster tissues. Mech Dev 2018; 153:10-16. [PMID: 30118816 DOI: 10.1016/j.mod.2018.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 08/13/2018] [Accepted: 08/13/2018] [Indexed: 10/28/2022]
Abstract
Single molecule Fluorescence in situ Hybridization (smFISH) for mRNA provides a powerful quantitative handle on expression from endogenous gene loci. While the method has been widely applied in cells in culture, applications to primary tissue samples remain fewer, and often use involved cryosectioning. Even apart from quantitative access to absolute transcript counts in specific tissue volumes, many other advantages of smFISH can be envisaged in tissue samples. Primary among these are the ability to report on subtle differences in expression among different cell types within a tissue, and the ability to correlate the expression from different target genes. Here, we present a modified method of smFISH applicable on various primary wholemount tissues from the fruit fly Drosophila melanogaster, and show the efficacy of the method in a variety of larval and adult tissue, and embryos. We also combine smFISH in tissue with immunofluorescence to demonstrate the possibility of capturing transcriptional and translational aspects of gene expression in the same tissue. Given the widespread use of Drosophila melanogaster as a model system in Developmental Biology and Genetics, such methods are likely to be of wide interest and could yield rich information about gene expression in tissues from this organism.
Collapse
Affiliation(s)
- Nikhita Pasnuri
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally, Serlingampally Mandal, Hyderabad 500107, Telangana, India
| | - Purnati Khuntia
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally, Serlingampally Mandal, Hyderabad 500107, Telangana, India
| | - Aprotim Mazumder
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P, Gopanpally, Serlingampally Mandal, Hyderabad 500107, Telangana, India.
| |
Collapse
|
15
|
Yang L, Titlow J, Ennis D, Smith C, Mitchell J, Young FL, Waddell S, Ish-Horowicz D, Davis I. Single molecule fluorescence in situ hybridisation for quantitating post-transcriptional regulation in Drosophila brains. Methods 2017; 126:166-176. [PMID: 28651965 PMCID: PMC5595163 DOI: 10.1016/j.ymeth.2017.06.025] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 05/22/2017] [Accepted: 06/21/2017] [Indexed: 02/01/2023] Open
Abstract
RNA in situ hybridization is a powerful method to investigate post-transcriptional regulation, but analysis of intracellular mRNA distributions in thick, complex tissues like the brain poses significant challenges. Here, we describe the application of single-molecule fluorescent in situ hybridization (smFISH) to quantitate primary nascent transcription and post-transcriptional regulation in whole-mount Drosophila larval and adult brains. Combining immunofluorescence and smFISH probes for different regions of a single gene, i.e., exons, 3'UTR, and introns, we show examples of a gene that is regulated post-transcriptionally and one that is regulated at the level of transcription. Our simple and rapid protocol can be used to co-visualise a variety of different transcripts and proteins in neuronal stem cells as well as deep brain structures such as mushroom body neuropils, using conventional confocal microscopy. Finally, we introduce the use of smFISH as a sensitive alternative to immunofluorescence for labelling specific neural stem cell populations in the brain.
Collapse
Affiliation(s)
- Lu Yang
- Department of Biochemistry, University of Oxford, United Kingdom
| | - Josh Titlow
- Department of Biochemistry, University of Oxford, United Kingdom
| | - Darragh Ennis
- Department of Biochemistry, University of Oxford, United Kingdom
| | - Carlas Smith
- Centre for Neural Circuits and Behaviour, University of Oxford, United Kingdom
| | - Jessica Mitchell
- Centre for Neural Circuits and Behaviour, University of Oxford, United Kingdom
| | | | - Scott Waddell
- Centre for Neural Circuits and Behaviour, University of Oxford, United Kingdom
| | - David Ish-Horowicz
- Department of Biochemistry, University of Oxford, United Kingdom
- LMCB, University College London, United Kingdom
| | - Ilan Davis
- Department of Biochemistry, University of Oxford, United Kingdom
| |
Collapse
|