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Bi Y, Li F, Guo X, Wang Z, Pan T, Guo Y, Webb GI, Yao J, Jia C, Song J. Clarion is a multi-label problem transformation method for identifying mRNA subcellular localizations. Brief Bioinform 2022; 23:bbac467. [PMID: 36341591 PMCID: PMC10148739 DOI: 10.1093/bib/bbac467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/09/2022] [Accepted: 09/29/2022] [Indexed: 11/09/2022] Open
Abstract
Subcellular localization of messenger RNAs (mRNAs) plays a key role in the spatial regulation of gene activity. The functions of mRNAs have been shown to be closely linked with their localizations. As such, understanding of the subcellular localizations of mRNAs can help elucidate gene regulatory networks. Despite several computational methods that have been developed to predict mRNA localizations within cells, there is still much room for improvement in predictive performance, especially for the multiple-location prediction. In this study, we proposed a novel multi-label multi-class predictor, termed Clarion, for mRNA subcellular localization prediction. Clarion was developed based on a manually curated benchmark dataset and leveraged the weighted series method for multi-label transformation. Extensive benchmarking tests demonstrated Clarion achieved competitive predictive performance and the weighted series method plays a crucial role in securing superior performance of Clarion. In addition, the independent test results indicate that Clarion outperformed the state-of-the-art methods and can secure accuracy of 81.47, 91.29, 79.77, 92.10, 89.15, 83.74, 80.74, 79.23 and 84.74% for chromatin, cytoplasm, cytosol, exosome, membrane, nucleolus, nucleoplasm, nucleus and ribosome, respectively. The webserver and local stand-alone tool of Clarion is freely available at http://monash.bioweb.cloud.edu.au/Clarion/.
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Affiliation(s)
- Yue Bi
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
- Monash Data Futures Institute, Monash University, Melbourne, Victoria 3800, Australia
| | - Fuyi Li
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
- College of Information Engineering, Northwest A&F University, Yangling, 712100, China
- Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, 792 Elizabeth Street, Melbourne, Victoria 3000, Australia
| | - Xudong Guo
- College of Information Engineering, Northwest A&F University, Yangling, 712100, China
| | - Zhikang Wang
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Tong Pan
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Yuming Guo
- Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria 3004, Australia
| | - Geoffrey I Webb
- Monash Data Futures Institute, Monash University, Melbourne, Victoria 3800, Australia
| | | | - Cangzhi Jia
- School of Science, Dalian Maritime University, Dalian 116026, China
| | - Jiangning Song
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria 3800, Australia
- Monash Data Futures Institute, Monash University, Melbourne, Victoria 3800, Australia
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2
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Zhang L, Si Q, Yang K, Zhang W, Okita TW, Tian L. mRNA Localization to the Endoplasmic Reticulum in Plant Endosperm Cells. Int J Mol Sci 2022; 23:13511. [PMID: 36362297 PMCID: PMC9656906 DOI: 10.3390/ijms232113511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/30/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
Subcellular mRNA localization is an evolutionarily conserved mechanism to spatially and temporally drive local translation and, in turn, protein targeting. Hence, this mechanism achieves precise control of gene expression and establishes functional and structural networks during cell growth and development as well as during stimuli response. Since its discovery in ascidian eggs, mRNA localization has been extensively studied in animal and yeast cells. Although our knowledge of subcellular mRNA localization in plant cells lags considerably behind other biological systems, mRNA localization to the endoplasmic reticulum (ER) has also been well established since its discovery in cereal endosperm cells in the early 1990s. Storage protein mRNA targeting to distinct subdomains of the ER determines efficient accumulation of the corresponding proteins in different endosomal storage sites and, in turn, underlies storage organelle biogenesis in cereal grains. The targeting process requires the presence of RNA localization elements, also called zipcodes, and specific RNA-binding proteins that recognize and bind these zipcodes and recruit other factors to mediate active transport. Here, we review the current knowledge of the mechanisms and functions of mRNA localization to the ER in plant cells and address directions for future research.
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Affiliation(s)
- Laining Zhang
- Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 310007, China
| | - Qidong Si
- Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 310007, China
| | - Kejie Yang
- Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 310007, China
| | - Wenwei Zhang
- Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 310007, China
| | - Thomas W. Okita
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Li Tian
- Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou 310007, China
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3
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Harris RL, Vetter MCYL, van Heerden E, Cason E, Vermeulen JG, Taneja A, Kieft TL, DeCoste CJ, Laevsky GS, Onstott TC. FISH-TAMB, a Fixation-Free mRNA Fluorescent Labeling Technique to Target Transcriptionally Active Members in Microbial Communities. MICROBIAL ECOLOGY 2022; 84:182-197. [PMID: 34406445 PMCID: PMC9250922 DOI: 10.1007/s00248-021-01809-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 06/23/2021] [Indexed: 06/13/2023]
Abstract
Keystone species or ecological engineers are vital to the health of an ecosystem; however, often, their low abundance or biomass present challenges for their discovery, identification, visualization and selection. We report the development of fluorescent in situ hybridization of transcript-annealing molecular beacons (FISH-TAMB), a fixation-free protocol that is applicable to archaea and bacteria. The FISH-TAMB method differs from existing FISH methods by the absence of fixatives or surfactants in buffers, the fast hybridization time of as short as 15 min at target cells' growth temperature, and the omission of washing steps. Polyarginine cell-penetrating peptides are employed to deliver molecular beacons (MBs) across prokaryotic cell walls and membranes, fluorescently labeling cells when MBs hybridize to target mRNA sequences. Here, the detailed protocol of the preparation and application of FISH-TAMB is presented. To demonstrate FISH-TAMB's ability to label intracellular mRNA targets, differentiate transcriptional states, detect active and rare taxa, and keep cell viability, labeling experiments were performed that targeted the messenger RNA (mRNA) of methyl-coenzyme M reductase A (mcrA) expressed in (1) Escherichia coli containing a plasmid with a partial mcrA gene of the methanogen Methanosarcina barkeri (E. coli mcrA+); (2) M. barkeri; and (3) an anaerobic methanotrophic (ANME) enrichment from a deep continental borehole. Although FISH-TAMB was initially envisioned for mRNA of any functional gene of interest without a requirement of prior knowledge of 16S ribosomal RNA (rRNA)-based taxonomy, FISH-TAMB has the potential for multiplexing and going beyond mRNA and thus is a versatile addition to the molecular ecologist's toolkit, with potentially widespread application in the field of environmental microbiology.
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Affiliation(s)
- Rachel L Harris
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA.
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA.
| | - Maggie C Y Lau Vetter
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA.
- Laboratory of Extraterrestrial Ocean Systems, Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, Hainan, China.
| | - Esta van Heerden
- Centre for Water Sciences and Management, North West University, Potchefstroom, South Africa
- iWater Pty Ltd, 5 Walter Sisulu Rd, Park West, Bloemfontein, 9301, South Africa
| | - Errol Cason
- Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, 9301, South Africa
- Department of Animal-, Wildlife- and Grassland Sciences, University of the Free State, Bloemfontein, 9301, South Africa
| | - Jan-G Vermeulen
- Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein, 9301, South Africa
- Department of Virology, University of the Free State, Bloemfontein, 9301, South Africa
| | - Anjali Taneja
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA
- McCourt School of Public Policy, Georgetown University, Washington, DC, 20057, USA
| | - Thomas L Kieft
- Department of Biology, New Mexico Institute of Mining and Technology, Socorro, NM, 87801, USA
| | - Christina J DeCoste
- Flow Cytometry Resource Facility, Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Gary S Laevsky
- Confocal Imaging Facility, Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Tullis C Onstott
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA
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4
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Feric M, Misteli T. Function moves biomolecular condensates in phase space. Bioessays 2022; 44:e2200001. [PMID: 35243657 PMCID: PMC9277701 DOI: 10.1002/bies.202200001] [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: 01/03/2022] [Revised: 02/19/2022] [Accepted: 02/22/2022] [Indexed: 11/08/2022]
Abstract
Phase separation underlies the formation of biomolecular condensates. We hypothesize the cellular processes that occur within condensates shape their structural features. We use the example of transcription to discuss structure-function relationships in condensates. Various types of transcriptional condensates have been reported across the evolutionary spectrum in the cell nucleus as well as in mitochondrial and bacterial nucleoids. In vitro and in vivo observations suggest that transcriptional activity of condensates influences their supramolecular structure, which in turn affects their function. Condensate organization thus becomes driven by differences in miscibility among the DNA and proteins of the transcription machinery and the RNA transcripts they generate. These considerations are in line with the notion that cellular processes shape the structural properties of condensates, leading to a dynamic, mutual interplay between structure and function in the cell.
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Affiliation(s)
- Marina Feric
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Tom Misteli
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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5
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Das S, Vera M, Gandin V, Singer RH, Tutucci E. Intracellular mRNA transport and localized translation. Nat Rev Mol Cell Biol 2021; 22:483-504. [PMID: 33837370 PMCID: PMC9346928 DOI: 10.1038/s41580-021-00356-8] [Citation(s) in RCA: 126] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2021] [Indexed: 02/08/2023]
Abstract
Fine-tuning cellular physiology in response to intracellular and environmental cues requires precise temporal and spatial control of gene expression. High-resolution imaging technologies to detect mRNAs and their translation state have revealed that all living organisms localize mRNAs in subcellular compartments and create translation hotspots, enabling cells to tune gene expression locally. Therefore, mRNA localization is a conserved and integral part of gene expression regulation from prokaryotic to eukaryotic cells. In this Review, we discuss the mechanisms of mRNA transport and local mRNA translation across the kingdoms of life and at organellar, subcellular and multicellular resolution. We also discuss the properties of messenger ribonucleoprotein and higher order RNA granules and how they may influence mRNA transport and local protein synthesis. Finally, we summarize the technological developments that allow us to study mRNA localization and local translation through the simultaneous detection of mRNAs and proteins in single cells, mRNA and nascent protein single-molecule imaging, and bulk RNA and protein detection methods.
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Affiliation(s)
- Sulagna Das
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, New York, NY, USA.,Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY, USA
| | - Maria Vera
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | | | - Robert H. Singer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, New York, NY, USA.,Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY, USA.,Janelia Research Campus of the HHMI, Ashburn, VA, USA.,;
| | - Evelina Tutucci
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,;
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6
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The Emergence of the Bilateral Symmetry in Animals: A Review and a New Hypothesis. Symmetry (Basel) 2021. [DOI: 10.3390/sym13020261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Most biological organisms exhibit different kinds of symmetry; an Animal (Metazoa), which is our Darwinist ancestor, has bilateral symmetry, and many plants exhibit rotational symmetry. It raises some questions: I. How can the evolution from an undifferentiated cell without bilateral symmetry to a complex biological organism with symmetry, which is based on asymmetric DNA and enzymes, lead to the bilateral symmetry? II. Is this evolution to an organism with bilateral symmetry obtained by other factors than DNA and enzymatic reactions? The existing literature about the evolution of the bilateral symmetry has been reviewed, and a new hypothesis has been formulated based on these reviews. The hypothesis is that the morphogenesis of biosystems is connected with the metabolism and that the oscillating kinetics in the Glycolysis have played a role in the polarity of the biological cells and in the establishment of the bilateral symmetry in Animals.
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7
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Irastortza-Olaziregi M, Amster-Choder O. RNA localization in prokaryotes: Where, when, how, and why. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1615. [PMID: 32851805 DOI: 10.1002/wrna.1615] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/27/2020] [Accepted: 06/02/2020] [Indexed: 12/27/2022]
Abstract
Only recently has it been recognized that the transcriptome of bacteria and archaea can be spatiotemporally regulated. All types of prokaryotic transcripts-rRNAs, tRNAs, mRNAs, and regulatory RNAs-may acquire specific localization and these patterns can be temporally regulated. In some cases bacterial RNAs reside in the vicinity of the transcription site, but in many others, transcripts show distinct localizations to the cytoplasm, the inner membrane, or the pole of rod-shaped species. This localization, which often overlaps with that of the encoded proteins, can be achieved either in a translation-dependent or translation-independent fashion. The latter implies that RNAs carry sequence-level features that determine their final localization with the aid of RNA-targeting factors. Localization of transcripts regulates their posttranscriptional fate by affecting their degradation and processing, translation efficiency, sRNA-mediated regulation, and/or propensity to undergo RNA modifications. By facilitating complex assembly and liquid-liquid phase separation, RNA localization is not only a consequence but also a driver of subcellular spatiotemporal complexity. We foresee that in the coming years the study of RNA localization in prokaryotes will produce important novel insights regarding the fundamental understanding of membrane-less subcellular organization and lead to practical outputs with biotechnological and therapeutic implications. This article is categorized under: RNA Export and Localization > RNA Localization Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Mikel Irastortza-Olaziregi
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Orna Amster-Choder
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
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8
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Greening C, Lithgow T. Formation and function of bacterial organelles. Nat Rev Microbiol 2020; 18:677-689. [PMID: 32710089 DOI: 10.1038/s41579-020-0413-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2020] [Indexed: 01/28/2023]
Abstract
Advances in imaging technologies have revealed that many bacteria possess organelles with a proteomically defined lumen and a macromolecular boundary. Some are bound by a lipid bilayer (such as thylakoids, magnetosomes and anammoxosomes), whereas others are defined by a lipid monolayer (such as lipid bodies), a proteinaceous coat (such as carboxysomes) or have a phase-defined boundary (such as nucleolus-like compartments). These diverse organelles have various metabolic and physiological functions, facilitating adaptation to different environments and driving the evolution of cellular complexity. This Review highlights that, despite the diversity of reported organelles, some unifying concepts underlie their formation, structure and function. Bacteria have fundamental mechanisms of organelle formation, through which conserved processes can form distinct organelles in different species depending on the proteins recruited to the luminal space and the boundary of the organelle. These complex subcellular compartments provide evolutionary advantages as well as enabling metabolic specialization, biogeochemical processes and biotechnological advances. Growing evidence suggests that the presence of organelles is the rule, rather than the exception, in bacterial cells.
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Affiliation(s)
- Chris Greening
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia.
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia.
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9
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Morgado S, Antunes D, Caffarena E, Vicente AC. The rare lncRNA GOLLD is widespread and structurally conserved among Mycobacterium tRNA arrays. RNA Biol 2020; 17:1001-1008. [PMID: 32275844 DOI: 10.1080/15476286.2020.1748922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Noncoding RNA (ncRNA) genes produce transcripts involved in a wide range of functions, including catalytic and regulatory functions. Besides, some transcripts have highly complex structures that may impact their activities. Among the largest bacterial ncRNAs, there is the rare GOLLD RNA, which is associated with tRNA genes and supposed to be chromosome- and phage-encoded in specialized groups of bacteria, including those from Lactobacillales and Actinomycetales orders. The only GOLLD structure was inferred from a variety of sequences, including many marine metagenomes. To explore GOLLD RNA in bacterial genomes, we mined the GOLLD gene in thousands of Mycobacterium and virus genomes using Infernal software. We identified this gene in 350 mycobacteria, including megaplasmids, and 39 bacteriophages, mainly in the genomic context of tRNA arrays. Mycobacterium GOLLD genes presented a high diversity and were distributed in three phylogenetic groups: (i) Mycobacterium exclusive; (ii) Mycobacterium and mycobacteriophages; and (iii) mycobacteriophage exclusive. We also determined the GOLLD secondary structure of each group using R2 R software based on GOLLD alignments generated by Infernal software. All GOLLD groups displayed a 3' half conserved structure, including utter E-loops pseudoknots substructures, also shared by non-Mycobacterium GOLLD while the 5' half motif was different among the groups. Here, we showed that the lncRNA GOLLD is widespread in Mycobacterium within tRNA arrays and corroborated the previously predicted GOLLD secondary structure.
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Affiliation(s)
- Sergio Morgado
- Laboratory of Molecular Genetics of Microorganisms, Oswaldo Cruz Institute (IOC - FIOCRUZ) , Rio de Janeiro, Brazil
| | - Deborah Antunes
- Laboratory of Functional Genomics and Bioinformatics, Oswaldo Cruz Institute (IOC - FIOCRUZ) , Rio de Janeiro, Brazil
| | - Ernesto Caffarena
- Computational Biophysics and Molecular Modeling Group, Scientific Computing Program (PROCC - FIOCRUZ) , Rio de Janeiro, Brazil
| | - Ana Carolina Vicente
- Laboratory of Molecular Genetics of Microorganisms, Oswaldo Cruz Institute (IOC - FIOCRUZ) , Rio de Janeiro, Brazil
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10
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Abstract
RNA localization is a key biological strategy for organizing the cytoplasm and generating both cellular and developmental polarity. During RNA localization, RNAs are targeted asymmetrically to specific subcellular destinations, resulting in spatially and temporally restricted gene expression through local protein synthesis. First discovered in oocytes and embryos, RNA localization is now recognized as a significant regulatory strategy for diverse RNAs, both coding and non-coding, in a wide range of cell types. Yet, the highly polarized cytoplasm of the oocyte remains a leading model to understand not only the principles and mechanisms underlying RNA localization, but also links to the formation of biomolecular condensates through phase separation. Here, we discuss both RNA localization and biomolecular condensates in oocytes with a particular focus on the oocyte of the frog, Xenopus laevis.
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Affiliation(s)
- Sarah E Cabral
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States
| | - Kimberly L Mowry
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States.
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11
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Carrier MC, Lalaouna D, Massé E. Broadening the Definition of Bacterial Small RNAs: Characteristics and Mechanisms of Action. Annu Rev Microbiol 2019; 72:141-161. [PMID: 30200848 DOI: 10.1146/annurev-micro-090817-062607] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The first report of trans-acting RNA-based regulation in bacterial cells dates back to 1984. Subsequent studies in diverse bacteria unraveled shared properties of trans-acting small regulatory RNAs, forming a clear definition of these molecules. These shared characteristics have been used extensively to identify new small RNAs (sRNAs) and their interactomes. Recently however, emerging technologies able to resolve RNA-RNA interactions have identified new types of regulatory RNAs. In this review, we present a broader definition of trans-acting sRNA regulators and discuss their newly discovered intrinsic characteristics.
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Affiliation(s)
- Marie-Claude Carrier
- RNA Group, Department of Biochemistry, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada; , ,
| | - David Lalaouna
- RNA Group, Department of Biochemistry, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada; , ,
| | - Eric Massé
- RNA Group, Department of Biochemistry, University of Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada; , ,
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12
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Abstract
RNA localization mechanisms have been intensively studied and include localized protection of mRNA from degradation, diffusion-coupled local entrapment of mRNA, and directed transport of mRNAs along the cytoskeleton. While it is well understood how cells utilize these three mechanisms to organize mRNAs within the cytoplasm, a newly appreciated mechanism of RNA localization has emerged in recent years in which mRNAs phase-separate and form liquid-like droplets. mRNAs both contribute to condensation of proteins into liquid-like structures and are themselves regulated by being incorporated into membraneless organelles. This ability to condense into droplets is in many instances contributing to previously appreciated mRNA localization phenomena. Here we review how phase separation enables mRNAs to selectively and efficiently colocalize and be coregulated, allowing control of gene expression in time and space.
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Affiliation(s)
- Erin M Langdon
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA;
| | - Amy S Gladfelter
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; .,Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA
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13
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Abstract
RNA-binding proteins (RBPs) are central to most if not all cellular processes, dictating the fate of virtually all RNA molecules in the cell. Starting with pioneering work on ribosomal proteins, studies of bacterial RBPs have paved the way for molecular studies of RNA-protein interactions. Work over the years has identified major RBPs that act on cellular transcripts at the various stages of bacterial gene expression and that enable their integration into post-transcriptional networks that also comprise small non-coding RNAs. Bacterial RBP research has now entered a new era in which RNA sequencing-based methods permit mapping of RBP activity in a truly global manner in vivo. Moreover, the soaring interest in understudied members of host-associated microbiota and environmental communities is likely to unveil new RBPs and to greatly expand our knowledge of RNA-protein interactions in bacteria.
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Affiliation(s)
- Erik Holmqvist
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany. .,Institute of Molecular Infection Biology, University of Würzburg, Würzburg, Germany.
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14
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Abstract
Diverse mechanisms and functions of posttranscriptional regulation by small regulatory RNAs and RNA-binding proteins have been described in bacteria. In contrast, little is known about the spatial organization of RNAs in bacterial cells. In eukaryotes, subcellular localization and transport of RNAs play important roles in diverse physiological processes, such as embryonic patterning, asymmetric cell division, epithelial polarity, and neuronal plasticity. It is now clear that bacterial RNAs also can accumulate at distinct sites in the cell. However, due to the small size of bacterial cells, RNA localization and localization-associated functions are more challenging to study in bacterial cells, and the underlying molecular mechanisms of transcript localization are less understood. Here, we review the emerging examples of RNAs localized to specific subcellular locations in bacteria, with indications that subcellular localization of transcripts might be important for gene expression and regulatory processes. Diverse mechanisms for bacterial RNA localization have been suggested, including close association to their genomic site of transcription, or to the localizations of their protein products in translation-dependent or -independent processes. We also provide an overview of the state of the art of technologies to visualize and track bacterial RNAs, ranging from hybridization-based approaches in fixed cells to in vivo imaging approaches using fluorescent protein reporters and/or RNA aptamers in single living bacterial cells. We conclude with a discussion of open questions in the field and ongoing technological developments regarding RNA imaging in eukaryotic systems that might likewise provide novel insights into RNA localization in bacteria.
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15
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Queiroz RML, Smith T, Villanueva E, Marti-Solano M, Monti M, Pizzinga M, Mirea DM, Ramakrishna M, Harvey RF, Dezi V, Thomas GH, Willis AE, Lilley KS. Comprehensive identification of RNA-protein interactions in any organism using orthogonal organic phase separation (OOPS). Nat Biotechnol 2019; 37:169-178. [PMID: 30607034 DOI: 10.1038/s41587-018-0001-2] [Citation(s) in RCA: 197] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 11/19/2018] [Indexed: 12/31/2022]
Abstract
Existing high-throughput methods to identify RNA-binding proteins (RBPs) are based on capture of polyadenylated RNAs and cannot recover proteins that interact with nonadenylated RNAs, including long noncoding RNA, pre-mRNAs and bacterial RNAs. We present orthogonal organic phase separation (OOPS), which does not require molecular tagging or capture of polyadenylated RNA, and apply it to recover cross-linked protein-RNA and free protein, or protein-bound RNA and free RNA, in an unbiased way. We validated OOPS in HEK293, U2OS and MCF10A human cell lines, and show that 96% of proteins recovered were bound to RNA. We show that all long RNAs can be cross-linked to proteins, and recovered 1,838 RBPs, including 926 putative novel RBPs. OOPS is approximately 100-fold more efficient than existing methods and can enable analyses of dynamic RNA-protein interactions. We also characterize dynamic changes in RNA-protein interactions in mammalian cells following nocodazole arrest, and present a bacterial RNA-interactome for Escherichia coli. OOPS is compatible with downstream proteomics and RNA sequencing, and can be applied in any organism.
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Affiliation(s)
- Rayner M L Queiroz
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Tom Smith
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Eneko Villanueva
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, UK.
| | | | - Mie Monti
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | - Dan-Mircea Mirea
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | | | - Veronica Dezi
- MRC Toxicology Unit, University of Cambridge, Leicester, UK
| | | | - Anne E Willis
- MRC Toxicology Unit, University of Cambridge, Leicester, UK
| | - Kathryn S Lilley
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Cambridge, UK.
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16
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Samacoits A, Chouaib R, Safieddine A, Traboulsi AM, Ouyang W, Zimmer C, Peter M, Bertrand E, Walter T, Mueller F. A computational framework to study sub-cellular RNA localization. Nat Commun 2018; 9:4584. [PMID: 30389932 PMCID: PMC6214940 DOI: 10.1038/s41467-018-06868-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 10/01/2018] [Indexed: 02/01/2023] Open
Abstract
RNA localization is a crucial process for cellular function and can be quantitatively studied by single molecule FISH (smFISH). Here, we present an integrated analysis framework to analyze sub-cellular RNA localization. Using simulated images, we design and validate a set of features describing different RNA localization patterns including polarized distribution, accumulation in cell extensions or foci, at the cell membrane or nuclear envelope. These features are largely invariant to RNA levels, work in multiple cell lines, and can measure localization strength in perturbation experiments. Most importantly, they allow classification by supervised and unsupervised learning at unprecedented accuracy. We successfully validate our approach on representative experimental data. This analysis reveals a surprisingly high degree of localization heterogeneity at the single cell level, indicating a dynamic and plastic nature of RNA localization. Automated analysis of RNA localisation in smFISH data has been elusive. Here, the authors simulate and use a large dataset of images to design and validate a framework for highly accurate classification of sub-cellular RNA localisation patterns from smFISH experiments.
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Affiliation(s)
- Aubin Samacoits
- Unité Imagerie et Modélisation, Institut Pasteur and CNRS UMR 3691, 28 rue du Docteur Roux, 75015, Paris, France.,C3BI, USR 3756 IP CNRS, 28 rue du Docteur Roux, 75015, Paris, France
| | - Racha Chouaib
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France.,Equipe labellisée Ligue Nationale Contre le Cancer, Paris, France
| | - Adham Safieddine
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France.,Equipe labellisée Ligue Nationale Contre le Cancer, Paris, France
| | - Abdel-Meneem Traboulsi
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France.,Equipe labellisée Ligue Nationale Contre le Cancer, Paris, France
| | - Wei Ouyang
- Unité Imagerie et Modélisation, Institut Pasteur and CNRS UMR 3691, 28 rue du Docteur Roux, 75015, Paris, France.,C3BI, USR 3756 IP CNRS, 28 rue du Docteur Roux, 75015, Paris, France
| | - Christophe Zimmer
- Unité Imagerie et Modélisation, Institut Pasteur and CNRS UMR 3691, 28 rue du Docteur Roux, 75015, Paris, France.,C3BI, USR 3756 IP CNRS, 28 rue du Docteur Roux, 75015, Paris, France
| | - Marion Peter
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France.,Equipe labellisée Ligue Nationale Contre le Cancer, Paris, France
| | - Edouard Bertrand
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France. .,Equipe labellisée Ligue Nationale Contre le Cancer, Paris, France.
| | - Thomas Walter
- MINES ParisTech, PSL-Research University, CBIO-Centre for Computational Biology, 75006, Paris, France. .,Institut Curie, PSL Research University, 75005, Paris, France. .,INSERM, U900, 75005, Paris, France.
| | - Florian Mueller
- Unité Imagerie et Modélisation, Institut Pasteur and CNRS UMR 3691, 28 rue du Docteur Roux, 75015, Paris, France. .,C3BI, USR 3756 IP CNRS, 28 rue du Docteur Roux, 75015, Paris, France.
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17
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Julius C, Yuzenkova Y. Noncanonical RNA-capping: Discovery, mechanism, and physiological role debate. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 10:e1512. [PMID: 30353673 DOI: 10.1002/wrna.1512] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/11/2018] [Accepted: 09/27/2018] [Indexed: 11/12/2022]
Abstract
Recently a new type of 5'-RNA cap was discovered. In contrast to the specialized eukaryotic m7 G cap, the novel caps are abundant cellular cofactors like NAD+ . RNAs capped with cofactors are found in prokaryotes and eukaryotes. Unlike m7 G cap, installed by specialized enzymes, cofactors are attached by main enzyme of transcription, RNA polymerase (RNAP). Cofactors act as noncanonical initiating substrates, provided cofactor's nucleoside base-pairs with template DNA at the transcription start site. Adenosine-containing NAD(H), flavin adenine dinucleotide (FAD), and CoA modify transcripts on promoters starting with +1A. Similarly, uridine-containing cell wall precursors, for example, uridine diphosphate-N-acetylglucosamine were shown to cap RNA in vitro on +1U promoters. Noncanonical capping is a universal feature of evolutionary unrelated RNAPs-multisubunit bacterial and eukaryotic RNAPs, and single-subunit mitochondrial RNAP. Cellular concentrations of cofactors, for example, NAD(H) are significantly higher than their Km in transcription. Yet, only a small proportion of a given cellular RNA is noncanonically capped (if at all). This proportion is a net balance between capping, seemingly stochastic, and decapping, possibly determined by RNA folding, protein binding and transcription rate. NUDIX hydrolases in bacteria and eukaryotes, and DXO family proteins eukaryotes act as decapping enzymes for noncanonical caps. The physiological role of noncanonical RNA capping is only starting to emerge. It was demonstrated to affect RNA stability in vivo in bacteria and eukaryotes and to stimulate RNAP promoter escape in vitro in Escherichia coli. NAD+ /NADH capping ratio may connect transcription to cellular redox state. Potentially, noncanonical capping affects mRNA translation, RNA-protein binding and RNA localization. This article is categorized under: RNA Processing > Capping and 5' End Modifications RNA Export and Localization > RNA Localization RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry.
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Affiliation(s)
- Christina Julius
- Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne, UK
| | - Yulia Yuzenkova
- Centre for Bacterial Cell Biology, Newcastle University, Newcastle upon Tyne, UK
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18
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Shao Q, Trinh JT, Zeng L. High-resolution studies of lysis-lysogeny decision-making in bacteriophage lambda. J Biol Chem 2018; 294:3343-3349. [PMID: 30242122 DOI: 10.1074/jbc.tm118.003209] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Cellular decision-making guides complex development such as cell differentiation and disease progression. Much of our knowledge about decision-making is derived from simple models, such as bacteriophage lambda infection, in which lambda chooses between the vegetative lytic fate and the dormant lysogenic fate. This paradigmatic system is broadly understood but lacking mechanistic details, partly due to limited resolution of past studies. Here, we discuss how modern technologies have enabled high-resolution examination of lambda decision-making to provide new insights and exciting possibilities in studying this classical system. The advent of techniques for labeling specific DNA, RNA, and proteins in cells allows for molecular-level characterization of events in lambda development. These capabilities yield both new answers and new questions regarding how the isolated lambda genetic circuit acts, what biological events transpire among phages in their natural context, and how the synergy of simple phage macromolecules brings about complex behaviors.
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Affiliation(s)
- Qiuyan Shao
- From the Department of Biochemistry and Biophysics and.,the Center for Phage Technology, Texas A&M University, College Station, Texas 77843
| | - Jimmy T Trinh
- From the Department of Biochemistry and Biophysics and.,the Center for Phage Technology, Texas A&M University, College Station, Texas 77843
| | - Lanying Zeng
- From the Department of Biochemistry and Biophysics and .,the Center for Phage Technology, Texas A&M University, College Station, Texas 77843
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19
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After the Fact(or): Posttranscriptional Gene Regulation in Enterohemorrhagic Escherichia coli O157:H7. J Bacteriol 2018; 200:JB.00228-18. [PMID: 29967119 DOI: 10.1128/jb.00228-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To adapt to ever-changing environments, pathogens quickly alter gene expression. This can occur through transcriptional, posttranscriptional, or posttranslational regulation. Historically, transcriptional regulation has been thoroughly studied to understand pathogen niche adaptation, whereas posttranscriptional and posttranslational gene regulation has only relatively recently been appreciated to play a central role in bacterial pathogenesis. Posttranscriptional regulation may involve chaperones, nucleases, and/or noncoding small RNAs (sRNAs) and typically controls gene expression by altering the stability and/or translation of the target mRNA. In this review, we highlight the global importance of posttranscriptional regulation to enterohemorrhagic Escherichia coli (EHEC) gene expression and discuss specific mechanisms of how EHEC regulates expression of virulence factors critical to host colonization and disease progression. The low infectious dose of this intestinal pathogen suggests that EHEC is particularly well adapted to respond to the host environment.
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20
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Malabirade A, Habier J, Heintz-Buschart A, May P, Godet J, Halder R, Etheridge A, Galas D, Wilmes P, Fritz JV. The RNA Complement of Outer Membrane Vesicles From Salmonella enterica Serovar Typhimurium Under Distinct Culture Conditions. Front Microbiol 2018; 9:2015. [PMID: 30214435 PMCID: PMC6125333 DOI: 10.3389/fmicb.2018.02015] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 08/09/2018] [Indexed: 12/20/2022] Open
Abstract
Bacterial outer membrane vesicles (OMVs), as well as OMV-associated small RNAs, have been demonstrated to play a role in host-pathogen interactions. The presence of larger RNA transcripts in OMVs has been less studied and their potential role in host-pathogen interactions remains largely unknown. Here we analyze RNA from OMVs secreted by Salmonella enterica serovar Typhimurium (S. Typhimurium) cultured under different conditions, which mimic host-pathogen interactions. S. Typhimurium was grown to exponential and stationary growth phases in minimal growth control medium (phosphate-carbon-nitrogen, PCN), as well as in acidic and phosphate-depleted PCN, comparable to the macrophage environment and inducing therefore the expression of Salmonella pathogenicity island 2 (SPI-2) genes. Moreover, Salmonella pathogenicity island 1 (SPI-1), which is required for virulence during the intestinal phase of infection, was induced by culturing S. Typhimurium to the stationary phase in Lysogeny Broth (LB). For each condition, we identified OMV-associated RNAs that are enriched in the extracellular environment relative to the intracellular space. All RNA classes could be observed, but a vast majority of rRNA was exported in all conditions in variable proportions with a notable decrease in LB SPI-1 inducing media. Several mRNAs and ncRNAs were specifically enriched in/on OMVs dependent on the growth conditions. Important to note is that some RNAs showed identical read coverage profiles intracellularly and extracellularly, whereas distinct coverage patterns were observed for other transcripts, suggesting a specific processing or degradation. Moreover, PCR experiments confirmed that distinct RNAs were present in or on OMVs as full-length transcripts (IsrB-1/2; IsrA; ffs; SsrS; CsrC; pSLT035; 10Sa; rnpB; STM0277; sseB; STM0972; STM2606), whereas others seemed to be rather present in a processed or degraded form. Finally, we show by a digestion protection assay that OMVs are able to prevent enzymatic degradation of given full-length transcripts (SsrS, CsrC, 10Sa, and rnpB). In summary, we show that OMV-associated RNA is clearly different in distinct culture conditions and that at least a fraction of the extracellular RNA is associated as a full-length transcripts with OMVs, indicating that some RNAs are protected by OMVs and thereby leaving open the possibility that those might be functionally active.
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Affiliation(s)
- Antoine Malabirade
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Janine Habier
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Anna Heintz-Buschart
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Julien Godet
- UMR CNRS 7021, Laboratoire de BioImagerie et Pathologies, Université de Strasbourg, Strasbourg, France
| | - Rashi Halder
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Alton Etheridge
- Pacific Northwest Research Institute, Seattle, WA, United States
| | - David Galas
- Pacific Northwest Research Institute, Seattle, WA, United States
| | - Paul Wilmes
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Joëlle V Fritz
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
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21
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Dynamics of translation can determine the spatial organization of membrane-bound proteins and their mRNA. Proc Natl Acad Sci U S A 2017; 114:13424-13429. [PMID: 29203677 PMCID: PMC5754755 DOI: 10.1073/pnas.1700941114] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Unlike most macromolecules that are homogeneously distributed in the bacterial cell, mRNAs that encode inner-membrane proteins can be concentrated near the inner membrane. Cotranslational insertion of the nascent peptide into the membrane brings the translating ribosome and the mRNA close to the membrane. This suggests that kinetic properties of translation can determine the spatial organization of these mRNAs and proteins, which can be modulated through posttranscriptional regulation. Here we use a simple stochastic model of translation to characterize the effect of mRNA properties on the dynamics and statistics of its spatial distribution. We show that a combination of the rate of translation initiation, the availability of secretory apparatuses, and the composition of the coding region determines the abundance of mRNAs near the membrane, as well as their residence time. We propose that the spatiotemporal dynamics of mRNAs can give rise to protein clusters on the membrane and determine their size distribution.
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22
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Fields C, Levin M. Multiscale memory and bioelectric error correction in the cytoplasm-cytoskeleton-membrane system. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 10. [DOI: 10.1002/wsbm.1410] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/19/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Chris Fields
- 21 Rue des Lavandiéres, 11160 Caunes Minervois; France
| | - Michael Levin
- Allen Discovery Center at Tufts University; Medford MA USA
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23
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Sheng H, Stauffer WT, Hussein R, Lin C, Lim HN. Nucleoid and cytoplasmic localization of small RNAs in Escherichia coli. Nucleic Acids Res 2017; 45:2919-2934. [PMID: 28119418 PMCID: PMC5389542 DOI: 10.1093/nar/gkx023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 01/09/2017] [Indexed: 12/23/2022] Open
Abstract
Bacterial small RNAs (sRNAs) regulate protein production by binding to mRNAs and altering their translation and degradation. sRNAs are smaller than most mRNAs but larger than many proteins. Therefore it is uncertain whether sRNAs can enter the nucleoid to target nascent mRNAs. Here, we investigate the intracellular localization of sRNAs transcribed from plasmids in Escherichia coli using RNA fluorescent in-situ hybridization. We found that sRNAs (GlmZ, OxyS, RyhB and SgrS) have equal preference for the nucleoid and cytoplasm, and no preferential localization at the cell membrane. We show using the gfp mRNA (encoding green fluorescent protein) that non-sRNAs can be engineered to have different proportions of nucleoid and cytoplasmic localization by altering their length and/or translation. The same localization as sRNAs was achieved by decreasing gfp mRNA length and translation, which suggests that sRNAs and other RNAs may enter the densely packed DNA of the nucleoid if they are sufficiently small. We also found that the Hfq protein, which binds sRNAs, minimally affects sRNA localization. Important implications of our findings for engineering synthetic circuits are: (i) sRNAs can potentially bind nascent mRNAs in the nucleoid, and (ii) localization patterns and distribution volumes of sRNAs can differ from some larger RNAs.
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Affiliation(s)
- Huanjie Sheng
- Department of Integrative Biology, 3060 Valley Life Sciences Building, Mail code 3140, University of California, Berkeley, CA, 94720-3140, USA
| | - Weston T Stauffer
- Department of Integrative Biology, 3060 Valley Life Sciences Building, Mail code 3140, University of California, Berkeley, CA, 94720-3140, USA
| | - Razika Hussein
- Department of Integrative Biology, 3060 Valley Life Sciences Building, Mail code 3140, University of California, Berkeley, CA, 94720-3140, USA
| | - Chris Lin
- Department of Integrative Biology, 3060 Valley Life Sciences Building, Mail code 3140, University of California, Berkeley, CA, 94720-3140, USA
| | - Han N Lim
- Department of Integrative Biology, 3060 Valley Life Sciences Building, Mail code 3140, University of California, Berkeley, CA, 94720-3140, USA
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24
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Teimouri H, Korkmazhan E, Stavans J, Levine E. Sub-cellular mRNA localization modulates the regulation of gene expression by small RNAs in bacteria. Phys Biol 2017; 14:056001. [PMID: 28350301 DOI: 10.1088/1478-3975/aa69ac] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Small non-coding RNAs can exert significant regulatory activity on gene expression in bacteria. In recent years, substantial progress has been made in understanding bacterial gene expression by sRNAs. However, recent findings that demonstrate that families of mRNAs show non-trivial sub-cellular distributions raise the question of how localization may affect the regulatory activity of sRNAs. Here we address this question within a simple mathematical model. We show that the non-uniform spatial distributions of mRNA can alter the threshold-linear response that characterizes sRNAs that act stoichiometrically, and modulate the hierarchy among targets co-regulated by the same sRNA. We also identify conditions where the sub-cellular organization of cofactors in the sRNA pathway can induce spatial heterogeneity on sRNA targets. Our results suggest that under certain conditions, interpretation and modeling of natural and synthetic gene regulatory circuits need to take into account the spatial organization of the transcripts of participating genes.
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Affiliation(s)
- Hamid Teimouri
- Department of Physics, Harvard University, Cambridge, MA 02138, United States of America
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25
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Abstract
Enteric pathogens of the family Enterobacteriaceae colonize various niches within animals and humans in which they compete with intestinal commensals and are attacked by the host immune system. To survive these hostile environments they possess complex, multilayer regulatory networks that coordinate the control of virulence factors, host-adapted metabolic functions and stress resistance. An important part of these intricate control networks are RNA-based control systems that enable the pathogen to fine-tune its responses. Recent next-generation sequencing approaches revealed a large repertoire of conserved and species-specific riboregulators, including numerous cis- and trans-acting non-coding RNAs, sensory RNA elements (RNA thermometers, riboswitches), regulatory RNA-binding proteins and RNA degrading enzymes which regulate colonization factors, toxins, host defense processes and virulence-relevant physiological and metabolic processes. All of which are important cues for pathogens to sense and respond to fluctuating conditions during the infection. This review covers infection-relevant riboregulators of E. coli, Salmonella, Shigella and Yersinia, highlights their versatile regulatory mechanisms, complex target regulons and functions, and discusses emerging topics and future challenges to fully understand and exploit RNA-based control to combat bacterial infections.
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Affiliation(s)
- Ann Kathrin Heroven
- a Department of Molecular Infection Biology , Helmholtz Centre for Infection Research , Braunschweig , Germany
| | - Aaron M Nuss
- a Department of Molecular Infection Biology , Helmholtz Centre for Infection Research , Braunschweig , Germany
| | - Petra Dersch
- a Department of Molecular Infection Biology , Helmholtz Centre for Infection Research , Braunschweig , Germany
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26
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The CsrA-FliW network controls polar localization of the dual-function flagellin mRNA in Campylobacter jejuni. Nat Commun 2016; 7:11667. [PMID: 27229370 PMCID: PMC4894983 DOI: 10.1038/ncomms11667] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 04/18/2016] [Indexed: 12/12/2022] Open
Abstract
The widespread CsrA/RsmA protein regulators repress translation by binding GGA motifs in bacterial mRNAs. CsrA activity is primarily controlled through sequestration by multiple small regulatory RNAs. Here we investigate CsrA activity control in the absence of antagonizing small RNAs by examining the CsrA regulon in the human pathogen Campylobacter jejuni. We use genome-wide co-immunoprecipitation combined with RNA sequencing to show that CsrA primarily binds flagellar mRNAs and identify the major flagellin mRNA (flaA) as the main CsrA target. The flaA mRNA is translationally repressed by CsrA, but it can also titrate CsrA activity. Together with the main C. jejuni CsrA antagonist, the FliW protein, flaA mRNA controls CsrA-mediated post-transcriptional regulation of other flagellar genes. RNA-FISH reveals that flaA mRNA is expressed and localized at the poles of elongating cells. Polar flaA mRNA localization is translation dependent and is post-transcriptionally regulated by the CsrA-FliW network. Overall, our results suggest a role for CsrA-FliW in spatiotemporal control of flagella assembly and localization of a dual-function mRNA.
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27
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Bakshi S, Choi H, Weisshaar JC. The spatial biology of transcription and translation in rapidly growing Escherichia coli. Front Microbiol 2015; 6:636. [PMID: 26191045 PMCID: PMC4488752 DOI: 10.3389/fmicb.2015.00636] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/12/2015] [Indexed: 11/21/2022] Open
Abstract
Single-molecule fluorescence provides high resolution spatial distributions of ribosomes and RNA polymerase (RNAP) in live, rapidly growing Escherichia coli. Ribosomes are more strongly segregated from the nucleoids (chromosomal DNA) than previous widefield fluorescence studies suggested. While most transcription may be co-translational, the evidence indicates that most translation occurs on free mRNA copies that have diffused from the nucleoids to a ribosome-rich region. Analysis of time-resolved images of the nucleoid spatial distribution after treatment with the transcription-halting drug rifampicin and the translation-halting drug chloramphenicol shows that both drugs cause nucleoid contraction on the 0–3 min timescale. This is consistent with the transertion hypothesis. We suggest that the longer-term (20–30 min) nucleoid expansion after Rif treatment arises from conversion of 70S-polysomes to 30S and 50S subunits, which readily penetrate the nucleoids. Monte Carlo simulations of a polymer bead model built to mimic the chromosomal DNA and ribosomes (either 70S-polysomes or 30S and 50S subunits) explain spatial segregation or mixing of ribosomes and nucleoids in terms of excluded volume and entropic effects alone. A comprehensive model of the transcription-translation-transertion system incorporates this new information about the spatial organization of the E. coli cytoplasm. We propose that transertion, which radially expands the nucleoids, is essential for recycling of 30S and 50S subunits from ribosome-rich regions back into the nucleoids. There they initiate co-transcriptional translation, which is an important mechanism for maintaining RNAP forward progress and protecting the nascent mRNA chain. Segregation of 70S-polysomes from the nucleoid may facilitate rapid growth by shortening the search time for ribosomes to find free mRNA concentrated outside the nucleoid and the search time for RNAP concentrated within the nucleoid to find transcription initiation sites.
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Affiliation(s)
- Somenath Bakshi
- Department of Chemistry and Molecular Biophysics Program, University of Wisconsin-Madison, Madison WI, USA
| | - Heejun Choi
- Department of Chemistry and Molecular Biophysics Program, University of Wisconsin-Madison, Madison WI, USA
| | - James C Weisshaar
- Department of Chemistry and Molecular Biophysics Program, University of Wisconsin-Madison, Madison WI, USA
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28
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Cyclic-di-GMP signaling in the Gram-positive pathogen Clostridium difficile. Curr Genet 2015; 61:497-502. [PMID: 25800812 DOI: 10.1007/s00294-015-0484-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 03/15/2015] [Indexed: 02/07/2023]
Abstract
The anaerobic Gram-positive bacterium Clostridium difficile causes intestinal infections responsible for symptoms ranging from mild diarrhea to fulminant colitis. Like other bacteria, C. difficile needs to sense and integrate environmental signals in order to adapt to changes and thrive in its environment. The second messenger cyclic diguanosine monophosphate (c-di-GMP) was recently recognized as a quasi-ubiquitous phenotype coordinator in bacteria. Mostly known to be involved in the transition from motile to sessile and multicellular behaviors in Gammaproteobacteria, c-di-GMP is now known to regulate many other phenotypes from cell morphogenesis to virulence, in many Gram-negative and a few Gram-positive bacteria. Herein, we review recent advances in our understanding of c-di-GMP signaling in the lifecycle of C. difficile.
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