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Mishra RK, Sharma P, Khaja FT, Uday AB, Hussain T. Cryo-EM structure of wheat ribosome reveals unique features of the plant ribosomes. Structure 2024; 32:562-574.e3. [PMID: 38458197 PMCID: PMC7616111 DOI: 10.1016/j.str.2024.02.006] [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: 08/16/2023] [Revised: 11/16/2023] [Accepted: 02/12/2024] [Indexed: 03/10/2024]
Abstract
Plants being sessile organisms exhibit unique features in ribosomes, which might aid in rapid gene expression and regulation in response to varying environmental conditions. Here, we present high-resolution structures of the 60S and 80S ribosomes from wheat, a monocot staple crop plant (Triticum aestivum). While plant ribosomes have unique plant-specific rRNA modification (Cm1847) in the peptide exit tunnel (PET), the zinc-finger motif in eL34 is absent, and uL4 is extended, making an exclusive interaction network. We note differences in the eL15-helix 11 (25S) interaction, eL6-ES7 assembly, and certain rRNA chemical modifications between monocot and dicot ribosomes. In eukaryotes, we observe highly conserved rRNA modification (Gm75) in 5.8S rRNA and a flipped base (G1506) in PET. These features are likely involved in sensing or stabilizing nascent chain. Finally, we discuss the importance of the universal conservation of three consecutive rRNA modifications in all ribosomes for their interaction with A-site aminoacyl-tRNA.
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Affiliation(s)
- Rishi Kumar Mishra
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bengaluru PIN-560012, India
| | - Prafful Sharma
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bengaluru PIN-560012, India
| | - Faisal Tarique Khaja
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bengaluru PIN-560012, India
| | - Adwaith B Uday
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bengaluru PIN-560012, India
| | - Tanweer Hussain
- Department of Developmental Biology and Genetics, Indian Institute of Science, Bengaluru PIN-560012, India.
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2
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Barozzi C, Zacchini F, Corradini AG, Morara M, Serra M, De Sanctis V, Bertorelli R, Dassi E, Montanaro L. Alterations of ribosomal RNA pseudouridylation in human breast cancer. NAR Cancer 2023; 5:zcad026. [PMID: 37260601 PMCID: PMC10227372 DOI: 10.1093/narcan/zcad026] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 05/12/2023] [Accepted: 05/17/2023] [Indexed: 06/02/2023] Open
Abstract
RNA modifications are key regulatory factors for several biological and pathological processes. They are abundantly represented on ribosomal RNA (rRNA), where they contribute to regulate ribosomal function in mRNA translation. Altered RNA modification pathways have been linked to tumorigenesis as well as to other human diseases. In this study we quantitatively evaluated the site-specific pseudouridylation pattern in rRNA in breast cancer samples exploiting the RBS-Seq technique involving RNA bisulfite treatment coupled with a new NGS approach. We found a wide variability among patients at different sites. The most dysregulated positions in tumors turned out to be hypermodified with respect to a reference RNA. As for 2'O-methylation level of rRNA modification, we detected variable and stable pseudouridine sites, with the most stable sites being the most evolutionary conserved. We also observed that pseudouridylation levels at specific sites are related to some clinical and bio-pathological tumor features and they are able to distinguish different patient clusters. This study is the first example of the contribution that newly available high-throughput approaches for site specific pseudouridine detection can provide to the understanding of the intrinsic ribosomal changes occurring in human tumors.
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Affiliation(s)
- Chiara Barozzi
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum - University of Bologna, Bologna I-40138, Italy
- Centre for Applied Biomedical Research – CRBA, University of Bologna, Sant’Orsola Hospital, Bologna I-40138, Italy
| | - Federico Zacchini
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum - University of Bologna, Bologna I-40138, Italy
- Centre for Applied Biomedical Research – CRBA, University of Bologna, Sant’Orsola Hospital, Bologna I-40138, Italy
| | - Angelo Gianluca Corradini
- Unit of Pathology, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Via Albertoni 15, I-40138 Bologna, Italy
| | - Monica Morara
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum - University of Bologna, Bologna I-40138, Italy
- Departmental Program in Laboratory Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Via Albertoni 15, I-40138 Bologna, Italy
| | - Margherita Serra
- Unit of Breast Surgery, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Via Albertoni 15, I-40138 Bologna, Italy
| | - Veronica De Sanctis
- Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Povo (TN) I-38123, Italy
| | - Roberto Bertorelli
- Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Povo (TN) I-38123, Italy
| | - Erik Dassi
- Department of Cellular, Computational and Integrative Biology - CIBIO, University of Trento, Povo (TN) I-38123, Italy
| | - Lorenzo Montanaro
- Department of Medical and Surgical Sciences (DIMEC), Alma Mater Studiorum - University of Bologna, Bologna I-40138, Italy
- Departmental Program in Laboratory Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Via Albertoni 15, I-40138 Bologna, Italy
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3
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Hariharan N, Ghosh S, Palakodeti D. The story of rRNA expansion segments: Finding functionality amidst diversity. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1732. [PMID: 35429135 DOI: 10.1002/wrna.1732] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 02/24/2022] [Accepted: 03/19/2022] [Indexed: 01/31/2023]
Abstract
Expansion segments (ESs) are multinucleotide insertions present across phyla at specific conserved positions in eukaryotic rRNAs. ESs are generally absent in bacterial rRNAs with some exceptions, while the archaeal rRNAs have microexpansions at regions that coincide with those of eukaryotic ESs. Although there is an increasing prominence of ribosomes, especially the ribosomal proteins, in fine-tuning gene expression through translation regulation, the role of rRNA ESs is relatively underexplored. While rRNAs have been established as the major catalytic hub in ribosome function, the presence of ESs widens their scope as a species-specific regulatory hub of protein synthesis. In this comprehensive review, we have elaborately discussed the current understanding of the functional aspects of rRNA ESs of cytoplasmic eukaryotic ribosomes and discuss their past, present, and future. This article is categorized under: RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems Translation > Ribosome Structure/Function Translation > Regulation.
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Affiliation(s)
- Nivedita Hariharan
- Technologies for the Advancement of Science, Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, India.,The University of Trans-disciplinary Health Sciences and Technology, Bangalore, India
| | - Sumana Ghosh
- Manipal Academy of Higher Education, Manipal, India
| | - Dasaradhi Palakodeti
- Technologies for the Advancement of Science, Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, India
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4
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Promising Assays for Examining a Putative Role of Ribosomal Heterogeneity in COVID-19 Susceptibility and Severity. Life (Basel) 2022; 12:life12020203. [PMID: 35207490 PMCID: PMC8880406 DOI: 10.3390/life12020203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/24/2022] [Accepted: 01/27/2022] [Indexed: 11/17/2022] Open
Abstract
The heterogeneity of ribosomes, characterized by structural variations, arises from differences in types, numbers, and/or post-translational modifications of participating ribosomal proteins (RPs), ribosomal RNAs (rRNAs) sequence variants plus post-transcriptional modifications, and additional molecules essential for forming a translational machinery. The ribosomal heterogeneity within an individual organism or a single cell leads to preferential translations of selected messenger RNA (mRNA) transcripts over others, especially in response to environmental cues. The role of ribosomal heterogeneity in SARS-CoV-2 coronavirus infection, propagation, related symptoms, or vaccine responses is not known, and a technique to examine these has not yet been developed. Tools to detect ribosomal heterogeneity or to profile translating mRNAs independently cannot identify unique or specialized ribosome(s) along with corresponding mRNA substrate(s). Concurrent characterizations of RPs and/or rRNAs with mRNA substrate from a single ribosome would be critical to decipher the putative role of ribosomal heterogeneity in the COVID-19 disease, caused by the SARS-CoV-2, which hijacks the host ribosome to preferentially translate its RNA genome. Such a protocol should be able to provide a high-throughput screening of clinical samples in a large population that would reach a statistical power for determining the impact of a specialized ribosome to specific characteristics of the disease. These characteristics may include host susceptibility, viral infectivity and transmissibility, severity of symptoms, antiviral treatment responses, and vaccine immunogenicity including its side effect and efficacy. In this study, several state-of-the-art techniques, in particular, chemical probing of ribosomal components or rRNA structures, proximity ligation to generate rRNA-mRNA chimeras for sequencing, nanopore gating of individual ribosomes, nanopore RNA sequencing and/or structural analyses, single-ribosome mass spectrometry, and microfluidic droplets for separating ribosomes or indexing rRNAs/mRNAs, are discussed. The key elements for further improvement and proper integration of the above techniques to potentially arrive at a high-throughput protocol for examining individual ribosomes and their mRNA substrates in a clinical setting are also presented.
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Jespersen N, Monrroy L, Barandun J. Impact of Genome Reduction in Microsporidia. EXPERIENTIA SUPPLEMENTUM (2012) 2022; 114:1-42. [PMID: 35543997 DOI: 10.1007/978-3-030-93306-7_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Microsporidia represent an evolutionary outlier in the tree of life and occupy the extreme edge of the eukaryotic domain with some of their biological features. Many of these unicellular fungi-like organisms have reduced their genomic content to potentially the lowest limit. With some of the most compacted eukaryotic genomes, microsporidia are excellent model organisms to study reductive evolution and its functional consequences. While the growing number of sequenced microsporidian genomes have elucidated genome composition and organization, a recent increase in complementary post-genomic studies has started to shed light on the impacts of genome reduction in these unique pathogens. This chapter will discuss the biological framework enabling genome minimization and will use one of the most ancient and essential macromolecular complexes, the ribosome, to illustrate the effects of extreme genome reduction on a structural, molecular, and cellular level. We outline how reductive evolution in microsporidia has shaped DNA organization, the composition and function of the ribosome, and the complexity of the ribosome biogenesis process. Studying compacted mechanisms, processes, or macromolecular machines in microsporidia illuminates their unique lifestyle and provides valuable insights for comparative eukaryotic structural biology.
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Affiliation(s)
- Nathan Jespersen
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Science for Life Laboratory, Umeå University, Umeå, Sweden.
| | - Leonardo Monrroy
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Science for Life Laboratory, Umeå University, Umeå, Sweden
| | - Jonas Barandun
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Science for Life Laboratory, Umeå University, Umeå, Sweden.
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6
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Streit D, Schleiff E. The Arabidopsis 2'-O-Ribose-Methylation and Pseudouridylation Landscape of rRNA in Comparison to Human and Yeast. FRONTIERS IN PLANT SCIENCE 2021; 12:684626. [PMID: 34381476 PMCID: PMC8351944 DOI: 10.3389/fpls.2021.684626] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/16/2021] [Indexed: 05/25/2023]
Abstract
Eukaryotic ribosome assembly starts in the nucleolus, where the ribosomal DNA (rDNA) is transcribed into the 35S pre-ribosomal RNA (pre-rRNA). More than two-hundred ribosome biogenesis factors (RBFs) and more than two-hundred small nucleolar RNAs (snoRNA) catalyze the processing, folding and modification of the rRNA in Arabidopsis thaliana. The initial pre-ribosomal 90S complex is formed already during transcription by association of ribosomal proteins (RPs) and RBFs. In addition, small nucleolar ribonucleoprotein particles (snoRNPs) composed of snoRNAs and RBFs catalyze the two major rRNA modification types, 2'-O-ribose-methylation and pseudouridylation. Besides these two modifications, rRNAs can also undergo base methylations and acetylation. However, the latter two modifications have not yet been systematically explored in plants. The snoRNAs of these snoRNPs serve as targeting factors to direct modifications to specific rRNA regions by antisense elements. Today, hundreds of different sites of modifications in the rRNA have been described for eukaryotic ribosomes in general. While our understanding of the general process of ribosome biogenesis has advanced rapidly, the diversities appearing during plant ribosome biogenesis is beginning to emerge. Today, more than two-hundred RBFs were identified by bioinformatics or biochemical approaches, including several plant specific factors. Similarly, more than two hundred snoRNA were predicted based on RNA sequencing experiments. Here, we discuss the predicted and verified rRNA modification sites and the corresponding identified snoRNAs on the example of the model plant Arabidopsis thaliana. Our summary uncovers the plant modification sites in comparison to the human and yeast modification sites.
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Affiliation(s)
- Deniz Streit
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Frankfurt, Germany
| | - Enrico Schleiff
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Frankfurt, Germany
- Frankfurt Institute for Advanced Studies (FIAS), Frankfurt, Germany
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7
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Gay DM, Lund AH, Jansson MD. Translational control through ribosome heterogeneity and functional specialization. Trends Biochem Sci 2021; 47:66-81. [PMID: 34312084 DOI: 10.1016/j.tibs.2021.07.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/18/2021] [Accepted: 07/01/2021] [Indexed: 12/31/2022]
Abstract
The conceptual origins of ribosome specialization can be traced back to the earliest days of molecular biology. Yet, this field has only recently begun to gather momentum, with numerous studies identifying distinct heterogeneous ribosome populations across multiple species and model systems. It is proposed that some of these compositionally distinct ribosomes may be functionally specialized and able to regulate the translation of specific mRNAs. Identification and functional characterization of specialized ribosomes has the potential to elucidate a novel layer of gene expression control, at the level of translation, where the ribosome itself is a key regulatory player. In this review, we discuss different sources of ribosome heterogeneity, evidence for ribosome specialization, and also the future directions of this exciting field.
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Affiliation(s)
- David M Gay
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anders H Lund
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
| | - Martin D Jansson
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
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8
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Leppek K, Fujii K, Quade N, Susanto TT, Boehringer D, Lenarčič T, Xue S, Genuth NR, Ban N, Barna M. Gene- and Species-Specific Hox mRNA Translation by Ribosome Expansion Segments. Mol Cell 2020; 80:980-995.e13. [PMID: 33202249 PMCID: PMC7769145 DOI: 10.1016/j.molcel.2020.10.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 12/24/2022]
Abstract
Ribosomes have been suggested to directly control gene regulation, but regulatory roles for ribosomal RNA (rRNA) remain largely unexplored. Expansion segments (ESs) consist of multitudes of tentacle-like rRNA structures extending from the core ribosome in eukaryotes. ESs are remarkably variable in sequence and size across eukaryotic evolution with largely unknown functions. In characterizing ribosome binding to a regulatory element within a Homeobox (Hox) 5' UTR, we identify a modular stem-loop within this element that binds to a single ES, ES9S. Engineering chimeric, "humanized" yeast ribosomes for ES9S reveals that an evolutionary change in the sequence of ES9S endows species-specific binding of Hoxa9 mRNA to the ribosome. Genome editing to site-specifically disrupt the Hoxa9-ES9S interaction demonstrates the functional importance for such selective mRNA-rRNA binding in translation control. Together, these studies unravel unexpected gene regulation directly mediated by rRNA and how ribosome evolution drives translation of critical developmental regulators.
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Affiliation(s)
- Kathrin Leppek
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Kotaro Fujii
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Nick Quade
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH Zürich, Zürich 8093, Switzerland
| | - Teodorus Theo Susanto
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Daniel Boehringer
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH Zürich, Zürich 8093, Switzerland
| | - Tea Lenarčič
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH Zürich, Zürich 8093, Switzerland
| | - Shifeng Xue
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Naomi R Genuth
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, Otto-Stern-Weg 5, ETH Zürich, Zürich 8093, Switzerland.
| | - Maria Barna
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA.
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9
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Banerjee AK, Blanco MR, Bruce EA, Honson DD, Chen LM, Chow A, Bhat P, Ollikainen N, Quinodoz SA, Loney C, Thai J, Miller ZD, Lin AE, Schmidt MM, Stewart DG, Goldfarb D, De Lorenzo G, Rihn SJ, Voorhees RM, Botten JW, Majumdar D, Guttman M. SARS-CoV-2 Disrupts Splicing, Translation, and Protein Trafficking to Suppress Host Defenses. Cell 2020; 183:1325-1339.e21. [PMID: 33080218 PMCID: PMC7543886 DOI: 10.1016/j.cell.2020.10.004] [Citation(s) in RCA: 365] [Impact Index Per Article: 91.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/26/2020] [Accepted: 10/02/2020] [Indexed: 12/26/2022]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a recently identified coronavirus that causes the respiratory disease known as coronavirus disease 2019 (COVID-19). Despite the urgent need, we still do not fully understand the molecular basis of SARS-CoV-2 pathogenesis. Here, we comprehensively define the interactions between SARS-CoV-2 proteins and human RNAs. NSP16 binds to the mRNA recognition domains of the U1 and U2 splicing RNAs and acts to suppress global mRNA splicing upon SARS-CoV-2 infection. NSP1 binds to 18S ribosomal RNA in the mRNA entry channel of the ribosome and leads to global inhibition of mRNA translation upon infection. Finally, NSP8 and NSP9 bind to the 7SL RNA in the signal recognition particle and interfere with protein trafficking to the cell membrane upon infection. Disruption of each of these essential cellular functions acts to suppress the interferon response to viral infection. Our results uncover a multipronged strategy utilized by SARS-CoV-2 to antagonize essential cellular processes to suppress host defenses. NSP16 binds mRNA recognition domains of U1/U2 snRNAs and disrupts mRNA splicing NSP1 binds in the mRNA entry channel of the ribosome to disrupt protein translation NSP8 and NSP9 bind the signal recognition particle and disrupt protein trafficking These disruptions of protein production suppress the interferon response to infection
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Affiliation(s)
- Abhik K Banerjee
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
| | - Mario R Blanco
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Emily A Bruce
- Departments of Medicine, Division of Immunobiology and Microbiology, and Molecular Genetics, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA
| | - Drew D Honson
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Linlin M Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Amy Chow
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Prashant Bhat
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Noah Ollikainen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sofia A Quinodoz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Colin Loney
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
| | - Jasmine Thai
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Zachary D Miller
- Department of Surgery and University of Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA
| | - Aaron E Lin
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Madaline M Schmidt
- Departments of Medicine, Division of Immunobiology and Microbiology, and Molecular Genetics, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA
| | - Douglas G Stewart
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
| | - Daniel Goldfarb
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
| | - Giuditta De Lorenzo
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
| | - Suzannah J Rihn
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
| | - Rebecca M Voorhees
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Jason W Botten
- Departments of Medicine, Division of Immunobiology and Microbiology, and Molecular Genetics, Larner College of Medicine, University of Vermont, Burlington, VT 05405, USA
| | - Devdoot Majumdar
- Department of Surgery and University of Vermont Cancer Center, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT 05405, USA.
| | - Mitchell Guttman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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10
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Symonová R. Integrative rDNAomics-Importance of the Oldest Repetitive Fraction of the Eukaryote Genome. Genes (Basel) 2019; 10:genes10050345. [PMID: 31067804 PMCID: PMC6562748 DOI: 10.3390/genes10050345] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 04/17/2019] [Accepted: 04/25/2019] [Indexed: 02/06/2023] Open
Abstract
Nuclear ribosomal RNA (rRNA) genes represent the oldest repetitive fraction universal to all eukaryotic genomes. Their deeply anchored universality and omnipresence during eukaryotic evolution reflects in multiple roles and functions reaching far beyond ribosomal synthesis. Merely the copy number of non-transcribed rRNA genes is involved in mechanisms governing e.g., maintenance of genome integrity and control of cellular aging. Their copy number can vary in response to environmental cues, in cellular stress sensing, in development of cancer and other diseases. While reaching hundreds of copies in humans, there are records of up to 20,000 copies in fish and frogs and even 400,000 copies in ciliates forming thus a literal subgenome or an rDNAome within the genome. From the compositional and evolutionary dynamics viewpoint, the precursor 45S rDNA represents universally GC-enriched, highly recombining and homogenized regions. Hence, it is not accidental that both rDNA sequence and the corresponding rRNA secondary structure belong to established phylogenetic markers broadly used to infer phylogeny on multiple taxonomical levels including species delimitation. However, these multiple roles of rDNAs have been treated and discussed as being separate and independent from each other. Here, I aim to address nuclear rDNAs in an integrative approach to better assess the complexity of rDNA importance in the evolutionary context.
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Affiliation(s)
- Radka Symonová
- Faculty of Science, Department of Biology, University of Hradec Králové, 500 03 Hradec Králové, Czech Republic.
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11
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RNA⁻Protein Interactions Prevent Long RNA Duplex Formation: Implications for the Design of RNA-Based Therapeutics. Molecules 2018; 23:molecules23123329. [PMID: 30558267 PMCID: PMC6321275 DOI: 10.3390/molecules23123329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 11/25/2022] Open
Abstract
Cells frequently simultaneously express RNAs and cognate antisense transcripts without necessarily leading to the formation of RNA duplexes. Here, we present a novel transcriptome-wide experimental approach to ascertain the presence of accessible double-stranded RNA structures based on sequencing of RNA fragments longer than 18 nucleotides that were not degraded by single-strand cutting nucleases. We applied this approach to four different cell lines with respect to three different treatments (native cell lysate, removal of proteins, and removal of ribosomal RNA and proteins). We found that long accessible RNA duplexes were largely absent in native cell lysates, while the number of RNA duplexes was dramatically higher when proteins were removed. The majority of RNA duplexes involved ribosomal transcripts. The duplex formation between different non-ribosomal transcripts appears to be largely of a stochastic nature. These results suggest that cells are—via RNA-binding proteins—mostly devoid of long RNA duplexes, leading to low “noise” in the molecular patterns that are utilized by the innate immune system. These findings have implications for the design of RNA interference (RNAi)-based therapeutics by imposing structural constraints on designed RNA complexes that are intended to have specific properties with respect to Dicer cleavage and target gene downregulation.
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