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Ramat A, Hannaford M, Januschke J. Maintenance of Miranda Localization in Drosophila Neuroblasts Involves Interaction with the Cognate mRNA. Curr Biol 2017; 27:2101-2111.e5. [PMID: 28690114 PMCID: PMC5526833 DOI: 10.1016/j.cub.2017.06.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 05/01/2017] [Accepted: 06/07/2017] [Indexed: 11/28/2022]
Abstract
How cells position their proteins is a key problem in cell biology. Targeting mRNAs to distinct regions of the cytoplasm contributes to protein localization by providing local control over translation. Here, we reveal that an interdependence of a protein and cognate mRNA maintains asymmetric protein distribution in mitotic Drosophila neural stem cells. We tagged endogenous mRNA or protein products of the gene miranda that is required for fate determination with GFP. We find that the mRNA localizes like the protein it encodes in a basal crescent in mitosis. We then used GFP-specific nanobodies fused to localization domains to alter the subcellular distribution of the GFP-tagged mRNA or protein. Altering the localization of the mRNA resulted in mislocalization of the protein and vice versa. Protein localization defects caused by mislocalization of the cognate mRNA were rescued by introducing untagged mRNA coding for mutant non-localizable protein. Therefore, by combining the MS2 system and subcellular nanobody expression, we uncovered that maintenance of Mira asymmetric localization requires interaction with the cognate mRNA.
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Affiliation(s)
- Anne Ramat
- Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dow Street, DD5 1EH Dundee, UK
| | - Matthew Hannaford
- Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dow Street, DD5 1EH Dundee, UK
| | - Jens Januschke
- Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dow Street, DD5 1EH Dundee, UK.
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2
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Eliscovich C, Singer RH. RNP transport in cell biology: the long and winding road. Curr Opin Cell Biol 2017; 45:38-46. [PMID: 28258033 DOI: 10.1016/j.ceb.2017.02.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 01/17/2017] [Accepted: 02/08/2017] [Indexed: 01/08/2023]
Abstract
Regulation of gene expression is key determinant to cell structure and function. RNA localization, where specific mRNAs are transported to subcellular regions and then translated, is highly conserved in eukaryotes ranging from yeast to extremely specialized and polarized cells such as neurons. Messenger RNA and associated proteins (mRNP) move from the site of transcription in the nucleus to their final destination in the cytoplasm both passively through diffusion and actively via directed transport. Dysfunction of RNA localization, transport and translation machinery can lead to pathology. Single-molecule live-cell imaging techniques have revealed unique features of this journey with unprecedented resolution. In this review, we highlight key recent findings that have been made using these approaches and possible implications for spatial control of gene function.
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Affiliation(s)
- Carolina Eliscovich
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, United States; Current address: Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, United States
| | - Robert H Singer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, United States; Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York 10461, United States; Janelia Research Campus of the HHMI, Ashburn, VA, 20147, United States.
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3
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Misra M, Edmund H, Ennis D, Schlueter MA, Marot JE, Tambasco J, Barlow I, Sigurbjornsdottir S, Mathew R, Vallés AM, Wojciech W, Roth S, Davis I, Leptin M, Gavis ER. A Genome-Wide Screen for Dendritically Localized RNAs Identifies Genes Required for Dendrite Morphogenesis. G3 (BETHESDA, MD.) 2016; 6:2397-405. [PMID: 27260999 PMCID: PMC4978894 DOI: 10.1534/g3.116.030353] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 05/27/2016] [Indexed: 12/15/2022]
Abstract
Localizing messenger RNAs at specific subcellular sites is a conserved mechanism for targeting the synthesis of cytoplasmic proteins to distinct subcellular domains, thereby generating the asymmetric protein distributions necessary for cellular and developmental polarity. However, the full range of transcripts that are asymmetrically distributed in specialized cell types, and the significance of their localization, especially in the nervous system, are not known. We used the EP-MS2 method, which combines EP transposon insertion with the MS2/MCP in vivo fluorescent labeling system, to screen for novel localized transcripts in polarized cells, focusing on the highly branched Drosophila class IV dendritic arborization neurons. Of a total of 541 lines screened, we identified 55 EP-MS2 insertions producing transcripts that were enriched in neuronal processes, particularly in dendrites. The 47 genes identified by these insertions encode molecularly diverse proteins, and are enriched for genes that function in neuronal development and physiology. RNAi-mediated knockdown confirmed roles for many of the candidate genes in dendrite morphogenesis. We propose that the transport of mRNAs encoded by these genes into the dendrites allows their expression to be regulated on a local scale during the dynamic developmental processes of dendrite outgrowth, branching, and/or remodeling.
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Affiliation(s)
- Mala Misra
- Department of Molecular Biology, Princeton University, NJ 08544
| | - Hendia Edmund
- Department of Molecular Biology, Princeton University, NJ 08544
| | - Darragh Ennis
- Department of Biochemistry, The University of Oxford, OX1 3QU, United Kingdom
| | | | - Jessica E Marot
- Department of Molecular Biology, Princeton University, NJ 08544
| | - Janet Tambasco
- Department of Molecular Biology, Princeton University, NJ 08544
| | - Ida Barlow
- Department of Molecular Biology, Princeton University, NJ 08544
| | | | - Renjith Mathew
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Ana Maria Vallés
- Department of Biochemistry, The University of Oxford, OX1 3QU, United Kingdom
| | - Waldemar Wojciech
- Biocenter, Institute of Developmental Biology, University of Cologne, 50674 Cologne, Germany
| | - Siegfried Roth
- Biocenter, Institute of Developmental Biology, University of Cologne, 50674 Cologne, Germany
| | - Ilan Davis
- Department of Biochemistry, The University of Oxford, OX1 3QU, United Kingdom
| | - Maria Leptin
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany Institute of Genetics, University of Cologne, 50674 Germany
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Ferraro T, Lucas T, Clémot M, De Las Heras Chanes J, Desponds J, Coppey M, Walczak AM, Dostatni N. New methods to image transcription in living fly embryos: the insights so far, and the prospects. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 5:296-310. [PMID: 26894441 PMCID: PMC5021148 DOI: 10.1002/wdev.221] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/28/2015] [Accepted: 10/30/2015] [Indexed: 11/08/2022]
Abstract
The regulation of transcription is a fundamental process underlying the determination of cell identity and its maintenance during development. In the last decades, most of the transcription factors, which have to be expressed at the right place and at the right time for the proper development of the fly embryo, have been identified. However, mostly because of the lack of methods to visualize transcription as the embryo develops, their coordinated spatiotemporal dynamics remains largely unexplored. Efforts have been made to decipher the transcription process with single molecule resolution at the single cell level. Recently, the fluorescent labeling of nascent RNA in developing fly embryos allowed the direct visualization of ongoing transcription at single loci within each nucleus. Together with powerful imaging and quantitative data analysis, these new methods provide unprecedented insights into the temporal dynamics of the transcription process and its intrinsic noise. Focusing on the Drosophila embryo, we discuss how the detection of single RNA molecules enhanced our comprehension of the transcription process and we outline the potential next steps made possible by these new imaging tools. In combination with genetics and theoretical analysis, these new imaging methods will aid the search for the mechanisms responsible for the robustness of development. For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Teresa Ferraro
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France.,Ecole Normale Superieure, PSL Research University, Paris, France
| | - Tanguy Lucas
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France
| | - Marie Clémot
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France
| | - Jose De Las Heras Chanes
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France
| | - Jonathan Desponds
- UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France.,Ecole Normale Superieure, PSL Research University, Paris, France
| | - Mathieu Coppey
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France
| | - Aleksandra M Walczak
- UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France.,Ecole Normale Superieure, PSL Research University, Paris, France
| | - Nathalie Dostatni
- Institut Curie, PSL Research University, Paris, France.,UPMC Univ Paris 06, Sorbonne Universités, Paris, France.,UMR3664/UMR168/UMR8549, CNRS, Paris, France
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Guidance of subcellular tubulogenesis by actin under the control of a synaptotagmin-like protein and Moesin. Nat Commun 2015; 5:3036. [PMID: 24413568 PMCID: PMC3945880 DOI: 10.1038/ncomms4036] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Accepted: 11/29/2013] [Indexed: 02/05/2023] Open
Abstract
Apical membranes in many polarized epithelial cells show specialized morphological adaptations that fulfil distinct physiological functions. The air-transporting tubules of Drosophila tracheal terminal cells represent an extreme case of membrane specialization. Here we show that Bitesize (Btsz), a synaptotagmin-like protein family member, is needed for luminal membrane morphogenesis. Unlike in multicellular tubes and other epithelia, where it influences apical integrity by affecting adherens junctions, Btsz here acts at a distance from junctions. Localized at the luminal membrane through its tandem C2 domain, it recruits activated Moesin. Both proteins are needed for the integrity of the actin cytoskeleton at the luminal membrane, but not for other pools of F-actin in the cell, nor do actin-dependent processes at the outer membrane, such as filopodial activity or membrane growth depend on Btsz. Btsz and Moesin guide luminal membrane morphogenesis through organizing actin and allowing the incorporation of membrane containing the apical determinant Crumbs. The terminal branches of the Drosophila tracheal network have intracellular tubules that grow through elongation of membrane invaginations. Here, the authors identify the synaptotagmin-like protein Bitesize as a regulator of actin-dependent luminal membrane morphogenesis.
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