1
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Goldberg GW, Kogenaru M, Keegan S, Haase MAB, Kagermazova L, Arias MA, Onyebeke K, Adams S, Beyer DK, Fenyö D, Noyes MB, Boeke JD. Engineered transcription-associated Cas9 targeting in eukaryotic cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.18.558319. [PMID: 37781609 PMCID: PMC10541143 DOI: 10.1101/2023.09.18.558319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
DNA targeting Class 2 CRISPR-Cas effector nucleases, including the well-studied Cas9 proteins, evolved protospacer-adjacent motif (PAM) and guide RNA interactions that sequentially license their binding and cleavage activities at protospacer target sites. Both interactions are nucleic acid sequence specific but function constitutively; thus, they provide intrinsic spatial control over DNA targeting activities but naturally lack temporal control. Here we show that engineered Cas9 fusion proteins which bind to nascent RNAs near a protospacer can facilitate spatiotemporal coupling between transcription and DNA targeting at that protospacer: Transcription-associated Cas9 Targeting (TraCT). Engineered TraCT is enabled in eukaryotic yeast or human cells when suboptimal PAM interactions limit basal activity and when one or more nascent RNA substrates are still tethered to the actively transcribed target DNA in cis. Using yeast, we further show that this phenomenon can be applied for selective editing at one of two identical targets in distinct gene loci, or, in diploid allelic loci that are differentially transcribed. Our work demonstrates that temporal control over Cas9's targeting activity at specific DNA sites may be engineered without modifying Cas9's core domains and guide RNA components or their expression levels. More broadly, it establishes co-transcriptional RNA binding as a cis-acting mechanism that can conditionally stimulate CRISPR-Cas DNA targeting in eukaryotic cells.
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Affiliation(s)
- Gregory W. Goldberg
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Manjunatha Kogenaru
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Sarah Keegan
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Max A. B. Haase
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Larisa Kagermazova
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Mauricio A. Arias
- Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA
| | - Kenenna Onyebeke
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Samantha Adams
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Daniel K. Beyer
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - David Fenyö
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Marcus B. Noyes
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Jef D. Boeke
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn NY 11201
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2
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Yang M, Rao G, Li L, Qi L, Ma C, Zhang H, Gong J, Wei B, Zhang XE, Chen G, Cao S, Li F. Transformation of a Viral Capsid from Nanocages to Nanotubes and Then to Hydrogels: Redirected Self-Assembly and Effects on Immunogenicity. ACS NANO 2024; 18:13755-13767. [PMID: 38752610 DOI: 10.1021/acsnano.4c01969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The ability to manipulate the self-assembly of proteins is essential to understanding the mechanisms of life and beneficial to fabricating advanced nanomaterials. Here, we report the transformation of the MS2 phage capsid from nanocages to nanotubes and then to nanotube hydrogels through simple point mutations guided by interfacial interaction redesign. We demonstrate that site 70, which lies in the flexible FG loop of the capsid protein (CP), is a "magic" site that can largely dictate the final morphology of assemblies. By varying the amino acid at site 70, with the aid of a cysteine-to-alanine mutation at site 46, we achieved the assembly of double-helical or single-helical nanotubes in addition to nanocages. Furthermore, an additional cysteine substitution on the surface of nanotubes mediated their cross-linking to form hydrogels with reducing agent responsiveness. The hierarchical self-assembly system allowed for the investigation of morphology-related immunogenicity of MS2 CPs, which revealed dramatic differences among nanocages, nanotubes, and nanotube hydrogels in terms of immune response types, antibody levels and T cell functions. This study provides insights into the assembly manipulation of protein nanomaterials and the customized design of nanovaccines and drug delivery systems.
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Affiliation(s)
- Mengsi Yang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guibo Rao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
| | - Long Li
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Linlin Qi
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China
| | - Chun Ma
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hui Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Gong
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin Wei
- Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Xian-En Zhang
- Faculty of Synthetic Biology, Shenzhen Institute of Advanced Technology, Shenzhen 518055, China
| | - Guosong Chen
- State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, China
| | - Sheng Cao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Feng Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Naskalska A, Heddle JG. Virus-like particles derived from bacteriophage MS2 as antigen scaffolds and RNA protective shells. Nanomedicine (Lond) 2024; 19:1103-1115. [PMID: 38629576 PMCID: PMC11225317 DOI: 10.2217/nnm-2023-0362] [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: 12/20/2023] [Accepted: 03/06/2024] [Indexed: 07/03/2024] Open
Abstract
The versatile potential of bacteriophage MS2-derived virus-like particles (VLPs) in medical biotechnology has been extensively studied during the last 30 years. Since the first reports showing that MS2 VLPs can be produced at high yield and relatively easily engineered, numerous applications have been proposed. Particular effort has been spent in developing MS2 VLPs as protective capsules and delivery platforms for diverse molecules, such as chemical compounds, proteins and nucleic acids. Among these, two are particularly noteworthy: as scaffolds displaying heterologous epitopes for vaccine development and as capsids for encapsulation of foreign RNA. In this review, we summarize the progress in developing MS2 VLPs for these two areas.
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Affiliation(s)
- Antonina Naskalska
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, 30-392, Poland
| | - Jonathan Gardiner Heddle
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, 30-392, Poland
- Department of Biosciences, Durham University, Durham, DH1 3LE, UK
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4
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Meng R, Xing Z, Chang JY, Yu Z, Thongchol J, Xiao W, Wang Y, Chamakura K, Zeng Z, Wang F, Young R, Zeng L, Zhang J. Structural basis of Acinetobacter type IV pili targeting by an RNA virus. Nat Commun 2024; 15:2746. [PMID: 38553443 PMCID: PMC10980823 DOI: 10.1038/s41467-024-47119-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 03/20/2024] [Indexed: 04/02/2024] Open
Abstract
Acinetobacters pose a significant threat to human health, especially those with weakened immune systems. Type IV pili of acinetobacters play crucial roles in virulence and antibiotic resistance. Single-stranded RNA bacteriophages target the bacterial retractile pili, including type IV. Our study delves into the interaction between Acinetobacter phage AP205 and type IV pili. Using cryo-electron microscopy, we solve structures of the AP205 virion with an asymmetric dimer of maturation proteins, the native Acinetobacter type IV pili bearing a distinct post-translational pilin cleavage, and the pili-bound AP205 showing its maturation proteins adapted to pilin modifications, allowing each phage to bind to one or two pili. Leveraging these results, we develop a 20-kilodalton AP205-derived protein scaffold targeting type IV pili in situ, with potential for research and diagnostics.
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Affiliation(s)
- Ran Meng
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
- Yale University, New Haven, CT, 06520, USA
| | - Zhongliang Xing
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Jeng-Yih Chang
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
- UMass Chan Medical School, Worcester, MA, 01655, USA
| | - Zihao Yu
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Jirapat Thongchol
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Wen Xiao
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Yuhang Wang
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Karthik Chamakura
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
- Armata Pharmaceuticals, Inc., Marina del Rey, CA, 90292, USA
| | - Zhiqi Zeng
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Fengbin Wang
- Department of Biochemistry and Molecular Genetics, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Ry Young
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Lanying Zeng
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Junjie Zhang
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA.
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5
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Nguyen HM, Watanabe S, Sharmin S, Kawaguchi T, Tan XE, Wannigama DL, Cui L. RNA and Single-Stranded DNA Phages: Unveiling the Promise from the Underexplored World of Viruses. Int J Mol Sci 2023; 24:17029. [PMID: 38069353 PMCID: PMC10707117 DOI: 10.3390/ijms242317029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/26/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
RNA and single-stranded DNA (ssDNA) phages make up an understudied subset of bacteriophages that have been rapidly expanding in the last decade thanks to advancements in metaviromics. Since their discovery, applications of genetic engineering to ssDNA and RNA phages have revealed their immense potential for diverse applications in healthcare and biotechnology. In this review, we explore the past and present applications of this underexplored group of phages, particularly their current usage as therapeutic agents against multidrug-resistant bacteria. We also discuss engineering techniques such as recombinant expression, CRISPR/Cas-based genome editing, and synthetic rebooting of phage-like particles for their role in tailoring phages for disease treatment, imaging, biomaterial development, and delivery systems. Recent breakthroughs in RNA phage engineering techniques are especially highlighted. We conclude with a perspective on challenges and future prospects, emphasizing the untapped diversity of ssDNA and RNA phages and their potential to revolutionize biotechnology and medicine.
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Affiliation(s)
- Huong Minh Nguyen
- Division of Bacteriology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (H.M.N.); (S.W.); (S.S.); (T.K.); (X.-E.T.)
| | - Shinya Watanabe
- Division of Bacteriology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (H.M.N.); (S.W.); (S.S.); (T.K.); (X.-E.T.)
| | - Sultana Sharmin
- Division of Bacteriology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (H.M.N.); (S.W.); (S.S.); (T.K.); (X.-E.T.)
| | - Tomofumi Kawaguchi
- Division of Bacteriology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (H.M.N.); (S.W.); (S.S.); (T.K.); (X.-E.T.)
| | - Xin-Ee Tan
- Division of Bacteriology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (H.M.N.); (S.W.); (S.S.); (T.K.); (X.-E.T.)
| | - Dhammika Leshan Wannigama
- Department of Infectious Diseases and Infection Control, Yamagata Prefectural Central Hospital, Yamagata 990-2292, Yamagata, Japan;
| | - Longzhu Cui
- Division of Bacteriology, Department of Infection and Immunity, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (H.M.N.); (S.W.); (S.S.); (T.K.); (X.-E.T.)
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6
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Gerber A, van Otterdijk S, Bruggeman FJ, Tutucci E. Understanding spatiotemporal coupling of gene expression using single molecule RNA imaging technologies. Transcription 2023; 14:105-126. [PMID: 37050882 PMCID: PMC10807504 DOI: 10.1080/21541264.2023.2199669] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/30/2023] [Accepted: 04/01/2023] [Indexed: 04/14/2023] Open
Abstract
Across all kingdoms of life, gene regulatory mechanisms underlie cellular adaptation to ever-changing environments. Regulation of gene expression adjusts protein synthesis and, in turn, cellular growth. Messenger RNAs are key molecules in the process of gene expression. Our ability to quantitatively measure mRNA expression in single cells has improved tremendously over the past decades. This revealed an unexpected coordination between the steps that control the life of an mRNA, from transcription to degradation. Here, we provide an overview of the state-of-the-art imaging approaches for measurement and quantitative understanding of gene expression, starting from the early visualizations of single genes by electron microscopy to current fluorescence-based approaches in single cells, including live-cell RNA-imaging approaches to FISH-based spatial transcriptomics across model organisms. We also highlight how these methods have shaped our current understanding of the spatiotemporal coupling between transcriptional and post-transcriptional events in prokaryotes. We conclude by discussing future challenges of this multidisciplinary field.Abbreviations: mRNA: messenger RNA; rRNA: ribosomal rDNA; tRNA: transfer RNA; sRNA: small RNA; FISH: fluorescence in situ hybridization; RNP: ribonucleoprotein; smFISH: single RNA molecule FISH; smiFISH: single molecule inexpensive FISH; HCR-FISH: Hybridization Chain-Reaction-FISH; RCA: Rolling Circle Amplification; seqFISH: Sequential FISH; MERFISH: Multiplexed error robust FISH; UTR: Untranslated region; RBP: RNA binding protein; FP: fluorescent protein; eGFP: enhanced GFP, MCP: MS2 coat protein; PCP: PP7 coat protein; MB: Molecular beacons; sgRNA: single guide RNA.
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Affiliation(s)
- Alan Gerber
- Amsterdam UMC, Location Vrije Universiteit Amsterdam, Department of Neurosurgery, Amsterdam, The Netherlands
- Cancer Center Amsterdam, Brain Tumor Center Amsterdam, Amsterdam, The Netherlands
| | - Sander van Otterdijk
- Systems Biology Lab, A-LIFE department, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Frank J. Bruggeman
- Systems Biology Lab, A-LIFE department, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Evelina Tutucci
- Systems Biology Lab, A-LIFE department, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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7
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Frey SJ, Carreño JM, Bielak D, Arsiwala A, Altomare CG, Varner C, Rosen-Cheriyan T, Bajic G, Krammer F, Kane RS. Nanovaccines Displaying the Influenza Virus Hemagglutinin in an Inverted Orientation Elicit an Enhanced Stalk-Directed Antibody Response. Adv Healthc Mater 2023; 12:e2202729. [PMID: 36689343 PMCID: PMC10386890 DOI: 10.1002/adhm.202202729] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 01/18/2023] [Indexed: 01/24/2023]
Abstract
Despite the availability of licensed vaccines, influenza causes considerable morbidity and mortality worldwide. Current influenza vaccines elicit an immune response that primarily targets the head domain of the viral glycoprotein hemagglutinin (HA). Influenza viruses, however, readily evade this response by acquiring mutations in the head domain. While vaccines that target the more conserved HA stalk may circumvent this problem, low levels of antistalk antibodies are elicited by vaccination, possibly due to the poor accessibility of the stalk domain to B cell receptors. In this work, it is demonstrated that nanoparticles presenting HA in an inverted orientation generate tenfold higher antistalk antibody titers after a prime immunization and fivefold higher antistalk titers after a boost than nanoparticles displaying HA in its regular orientation. Moreover, nanoparticles presenting HA in an inverted orientation elicit a broader antistalk response that reduces mouse weight loss and improves survival after challenge to a greater extent than nanoparticles displaying HA in a regular orientation. Refocusing the antibody response toward conserved epitopes by controlling antigen orientation may enable the design of broadly protective nanovaccines targeting influenza viruses and other pathogens with pandemic potential.
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Affiliation(s)
- Steven J Frey
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Juan Manuel Carreño
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Dominika Bielak
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Ammar Arsiwala
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Clara G Altomare
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Chad Varner
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Tania Rosen-Cheriyan
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Goran Bajic
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Florian Krammer
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Center for Vaccine Research and Pandemic Preparedness (C-VaRPP), Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Pathology, Molecular and Cell Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Ravi S Kane
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
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8
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Vezeau GE, Gadila LR, Salis HM. Automated design of protein-binding riboswitches for sensing human biomarkers in a cell-free expression system. Nat Commun 2023; 14:2416. [PMID: 37105971 PMCID: PMC10140043 DOI: 10.1038/s41467-023-38098-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Cell-free genetically encoded biosensors have been developed to detect small molecules and nucleic acids, but they have yet to be reliably engineered to detect proteins. Here we develop an automated platform to convert protein-binding RNA aptamers into riboswitch sensors that operate within low-cost cell-free assays. We demonstrate the platform by engineering 35 protein-sensing riboswitches for human monomeric C-reactive protein, human interleukin-32γ, and phage MS2 coat protein. The riboswitch sensors regulate output expression levels by up to 16-fold with input protein concentrations within the human serum range. We identify two distinct mechanisms governing riboswitch-mediated regulation of translation rates and leverage computational analysis to refine the protein-binding aptamer regions, improving design accuracy. Overall, we expand the cell-free sensor toolbox and demonstrate how computational design is used to develop protein-sensing riboswitches with future applications as low-cost medical diagnostics.
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Affiliation(s)
- Grace E Vezeau
- Department of Agricultural and Biological Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Lipika R Gadila
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Howard M Salis
- Department of Agricultural and Biological Engineering, Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, 16802, USA.
- Huck Institute Bioinformatics and Genomics Graduate Program, Pennsylvania State University, University Park, PA, 16802, USA.
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9
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Halfmann PJ, Frey SJ, Loeffler K, Kuroda M, Maemura T, Armbrust T, Yang JE, Hou YJ, Baric R, Wright ER, Kawaoka Y, Kane RS. Multivalent S2-based vaccines provide broad protection against SARS-CoV-2 variants of concern and pangolin coronaviruses. EBioMedicine 2022; 86:104341. [PMID: 36375316 PMCID: PMC9651965 DOI: 10.1016/j.ebiom.2022.104341] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/12/2022] [Accepted: 10/18/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The COVID-19 pandemic continues to cause morbidity and mortality worldwide. Most approved COVID-19 vaccines generate a neutralizing antibody response that primarily targets the highly variable receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) protein. SARS-CoV-2 "variants of concern" have acquired mutations in this domain allowing them to evade vaccine-induced humoral immunity. Recent approaches to improve the breadth of protection beyond SARS-CoV-2 have required the use of mixtures of RBD antigens from different sarbecoviruses. It may therefore be beneficial to develop a vaccine in which the protective immune response targets a more conserved region of the S protein. METHODS Here we have developed a vaccine based on the conserved S2 subunit of the S protein and optimized the adjuvant and immunization regimen in Syrian hamsters and BALB/c mice. We have characterized the efficacy of the vaccine against SARS-CoV-2 variants and other coronaviruses. FINDINGS Immunization with S2-based constructs elicited a broadly cross-reactive IgG antibody response that recognized the spike proteins of not only SARS-CoV-2 variants, but also SARS-CoV-1, and the four endemic human coronaviruses. Importantly, immunization reduced virus titers in respiratory tissues in vaccinated animals challenged with SARS-CoV-2 variants B.1.351 (beta), B.1.617.2 (delta), and BA.1 (omicron) as well as a pangolin coronavirus. INTERPRETATION These results suggest that S2-based constructs can elicit a broadly cross-reactive antibody response resulting in limited virus replication, thus providing a framework for designing vaccines that elicit broad protection against coronaviruses. FUNDING NIH, Japan Agency for Medical Research and Development, Garry Betty/ V Foundation Chair Fund, and NSF.
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Affiliation(s)
- Peter J Halfmann
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53711, USA
| | - Steven J Frey
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Kathryn Loeffler
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Makoto Kuroda
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53711, USA
| | - Tadashi Maemura
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53711, USA
| | - Tammy Armbrust
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53711, USA
| | - Jie E Yang
- Department of Biochemistry, University of Wisconsin, Madison, WI, 53706, USA; Cryo-EM Research Center, Department of Biochemistry, University of Wisconsin, Madison, WI, 53706, USA; Midwest Center for Cryo-Electron Tomography, Department of Biochemistry, University of Wisconsin, Madison, WI, 53706, USA
| | - Yixuan J Hou
- Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Ralph Baric
- Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Elizabeth R Wright
- Department of Biochemistry, University of Wisconsin, Madison, WI, 53706, USA; Cryo-EM Research Center, Department of Biochemistry, University of Wisconsin, Madison, WI, 53706, USA; Midwest Center for Cryo-Electron Tomography, Department of Biochemistry, University of Wisconsin, Madison, WI, 53706, USA
| | - Yoshihiro Kawaoka
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, 53711, USA; Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan.
| | - Ravi S Kane
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
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10
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Chandler-Bostock R, Bingham RJ, Clark S, Scott AJP, Wroblewski E, Barker A, White SJ, Dykeman EC, Mata CP, Bohon J, Farquhar E, Twarock R, Stockley PG. Genome-regulated Assembly of a ssRNA Virus May Also Prepare It for Infection. J Mol Biol 2022; 434:167797. [PMID: 35998704 DOI: 10.1016/j.jmb.2022.167797] [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: 05/20/2022] [Revised: 08/09/2022] [Accepted: 08/15/2022] [Indexed: 11/17/2022]
Abstract
Many single-stranded, positive-sense RNA viruses regulate assembly of their infectious virions by forming multiple, cognate coat protein (CP)-genome contacts at sites termed Packaging Signals (PSs). We have determined the secondary structures of the bacteriophage MS2 ssRNA genome (gRNA) frozen in defined states using constraints from X-ray synchrotron footprinting (XRF). Comparison of the footprints from phage and transcript confirms the presence of multiple PSs in contact with CP dimers in the former. This is also true for a virus-like particle (VLP) assembled around the gRNA in vitro in the absence of the single-copy Maturation Protein (MP) found in phage. Since PS folds are present at many sites across gRNA transcripts, it appears that this genome has evolved to facilitate this mechanism of assembly regulation. There are striking differences between the gRNA-CP contacts seen in phage and the VLP, suggesting that the latter are inappropriate surrogates for aspects of phage structure/function. Roughly 50% of potential PS sites in the gRNA are not in contact with the protein shell of phage. However, many of these sit adjacent to, albeit not in contact with, PS-binding sites on CP dimers. We hypothesize that these act as PSs transiently during assembly but subsequently dissociate. Combining the XRF data with PS locations from an asymmetric cryo-EM reconstruction suggests that the genome positions of such dissociations are non-random and may facilitate infection. The loss of many PS-CP interactions towards the 3' end of the gRNA would allow this part of the genome to transit more easily through the narrow basal body of the pilus extruding machinery. This is the known first step in phage infection. In addition, each PS-CP dissociation event leaves the protein partner trapped in a non-lowest free-energy conformation. This destabilizes the protein shell which must disassemble during infection, further facilitating this stage of the life-cycle.
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Affiliation(s)
| | - Richard J Bingham
- Departments of Mathematics and Biology & York Cross-Disciplinary Centre for Systems Analysis, University of York, York, UK
| | - Sam Clark
- Departments of Mathematics and Biology & York Cross-Disciplinary Centre for Systems Analysis, University of York, York, UK
| | - Andrew J P Scott
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Emma Wroblewski
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Amy Barker
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Simon J White
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Eric C Dykeman
- Departments of Mathematics and Biology & York Cross-Disciplinary Centre for Systems Analysis, University of York, York, UK
| | - Carlos P Mata
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Jen Bohon
- CWRU Center for Synchrotron Biosciences, NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Erik Farquhar
- CWRU Center for Synchrotron Biosciences, NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Reidun Twarock
- Departments of Mathematics and Biology & York Cross-Disciplinary Centre for Systems Analysis, University of York, York, UK.
| | - Peter G Stockley
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
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11
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Adlhart M, Poetsch F, Hlevnjak M, Hoogmoed M, Polyansky A, Zagrovic B. Compositional complementarity between genomic RNA and coat proteins in positive-sense single-stranded RNA viruses. Nucleic Acids Res 2022; 50:4054-4067. [PMID: 35357492 PMCID: PMC9023274 DOI: 10.1093/nar/gkac202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/29/2022] [Indexed: 02/02/2023] Open
Abstract
During packaging in positive-sense single-stranded RNA (+ssRNA) viruses, coat proteins (CPs) interact directly with multiple regions in genomic RNA (gRNA), but the underlying physicochemical principles remain unclear. Here we analyze the high-resolution cryo-EM structure of bacteriophage MS2 and show that the gRNA/CP binding sites, including the known packaging signal, overlap significantly with regions where gRNA nucleobase-density profiles match the corresponding CP nucleobase-affinity profiles. Moreover, we show that the MS2 packaging signal corresponds to the global minimum in gRNA/CP interaction energy in the unstructured state as derived using a linearly additive model and knowledge-based nucleobase/amino-acid affinities. Motivated by this, we predict gRNA/CP interaction sites for a comprehensive set of 1082 +ssRNA viruses. We validate our predictions by comparing them with site-resolved information on gRNA/CP interactions derived in SELEX and CLIP experiments for 10 different viruses. Finally, we show that in experimentally studied systems CPs frequently interact with autologous coding regions in gRNA, in agreement with both predicted interaction energies and a recent proposal that proteins in general tend to interact with own mRNAs, if unstructured. Our results define a self-consistent framework for understanding packaging in +ssRNA viruses and implicate interactions between unstructured gRNA and CPs in the process.
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Affiliation(s)
- Marlene Adlhart
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Campus Vienna Biocenter 5, A-1030, Vienna, Austria
| | - Florian Poetsch
- Institute for Physiology and Pathophysiology, Center for Medical Research, Johannes Kepler University of Linz, Huemerstraße 3-5, 4020 Linz, Austria
| | - Mario Hlevnjak
- Division of Molecular Genetics, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Megan Hoogmoed
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Campus Vienna Biocenter 5, A-1030, Vienna, Austria
| | - Anton A Polyansky
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Campus Vienna Biocenter 5, A-1030, Vienna, Austria
| | - Bojan Zagrovic
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Campus Vienna Biocenter 5, A-1030, Vienna, Austria
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12
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Optimizing the synthesis and purification of MS2 virus like particles. Sci Rep 2021; 11:19851. [PMID: 34615923 PMCID: PMC8494748 DOI: 10.1038/s41598-021-98706-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 09/14/2021] [Indexed: 02/08/2023] Open
Abstract
Introducing bacteriophage MS2 virus-like particles (VLPs) as gene and drug delivery tools increases the demand for optimizing their production and purification procedure. PEG precipitation method is used efficiently to purify VLPs, while the effects of pH and different electrolytes on the stability, size, and homogeneity of purified MS2 VLPs, and the encapsulated RNA sequences remained to be elucidated. In this regard, a vector, capable of producing VLP with an shRNA packed inside was prepared. The resulting VLPs in different buffers/solutions were assessed for their size, polydispersity index, and ability to protect the enclosed shRNA. We report that among Tris, HEPES, and PBS, with or without NaNO3, and also NaNO3 alone in different pH and ionic concentrations, the 100 mM NaNO3-Tris buffer with pH:8 can be used as a new and optimal MS2 VLP production buffer, capable of inhibiting the VLPs aggregation. These VLPs show a size range of 27-30 nm and suitable homogeneity with minimum 12-month stability at 4 °C. Moreover, the resulting MS2 VLPs were highly efficient and stable for at least 48 h in conditions similar to in vivo. These features of MS2 VLPs produced in the newly introduced buffer make them an appropriate candidate for therapeutic agents' delivery.
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13
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Lalwani Prakash D, Gosavi S. Understanding the Folding Mediated Assembly of the Bacteriophage MS2 Coat Protein Dimers. J Phys Chem B 2021; 125:8722-8732. [PMID: 34339197 DOI: 10.1021/acs.jpcb.1c03928] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The capsids of RNA viruses such as MS2 are great models for studying protein self-assembly because they are made almost entirely of multiple copies of a single coat protein (CP). Although CP is the minimal repeating unit of the capsid, previous studies have shown that CP exists as a homodimer (CP2) even in an acid-disassembled system, indicating that CP2 is an obligate dimer. Here, we investigate the molecular basis of this obligate dimerization using coarse-grained structure-based models and molecular dynamics simulations. We find that, unlike monomeric proteins of similar size, CP populates a single partially folded ensemble whose "foldedness" is sensitive to denaturing conditions. In contrast, CP2 folds similarly to single-domain proteins populating only the folded and the unfolded ensembles, separated by a prominent folding free energy barrier. Several intramonomer contacts form early, but the CP2 folding barrier is crossed only when the intermonomer contacts are made. A dissection of the structure of CP2 through mutant folding simulations shows that the folding barrier arises both from the topology of CP and the interface contacts of CP2. Together, our results show that CP2 is an obligate dimer because of kinetic stability, that is, dimerization induces a folding barrier and that makes it difficult for proteins in the dimer minimum to partially unfold and access the monomeric state without completely unfolding. We discuss the advantages of this obligate dimerization in the context of dimer design and virus stability.
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Affiliation(s)
- Digvijay Lalwani Prakash
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Shachi Gosavi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
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14
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Chiba S, Frey SJ, Halfmann PJ, Kuroda M, Maemura T, Yang JE, Wright ER, Kawaoka Y, Kane RS. Multivalent nanoparticle-based vaccines protect hamsters against SARS-CoV-2 after a single immunization. Commun Biol 2021; 4:597. [PMID: 34011948 PMCID: PMC8134492 DOI: 10.1038/s42003-021-02128-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 04/20/2021] [Indexed: 12/11/2022] Open
Abstract
The COVID-19 pandemic continues to wreak havoc as worldwide SARS-CoV-2 infection, hospitalization, and death rates climb unabated. Effective vaccines remain the most promising approach to counter SARS-CoV-2. Yet, while promising results are emerging from COVID-19 vaccine trials, the need for multiple doses and the challenges associated with the widespread distribution and administration of vaccines remain concerns. Here, we engineered the coat protein of the MS2 bacteriophage and generated nanoparticles displaying multiple copies of the SARS-CoV-2 spike (S) protein. The use of these nanoparticles as vaccines generated high neutralizing antibody titers and protected Syrian hamsters from a challenge with SARS-CoV-2 after a single immunization with no infectious virus detected in the lungs. This nanoparticle-based vaccine platform thus provides protection after a single immunization and may be broadly applicable for protecting against SARS-CoV-2 and future pathogens with pandemic potential.
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MESH Headings
- Animals
- Antibodies, Neutralizing/biosynthesis
- Antibodies, Viral/biosynthesis
- COVID-19/immunology
- COVID-19/prevention & control
- COVID-19 Vaccines/administration & dosage
- COVID-19 Vaccines/genetics
- COVID-19 Vaccines/immunology
- Drug Delivery Systems
- Female
- Humans
- Immunization/methods
- Levivirus/genetics
- Levivirus/immunology
- Mesocricetus
- Microscopy, Electron, Transmission
- Models, Animal
- Nanoparticles/administration & dosage
- Nanoparticles/ultrastructure
- Nanotechnology
- Pandemics/prevention & control
- Protein Engineering
- SARS-CoV-2/immunology
- Spike Glycoprotein, Coronavirus/administration & dosage
- Spike Glycoprotein, Coronavirus/immunology
- Vaccines, Combined/administration & dosage
- Vaccines, Combined/genetics
- Vaccines, Combined/immunology
- Vaccines, Virus-Like Particle/administration & dosage
- Vaccines, Virus-Like Particle/genetics
- Vaccines, Virus-Like Particle/immunology
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Affiliation(s)
- Shiho Chiba
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - Steven J Frey
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Peter J Halfmann
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - Makoto Kuroda
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - Tadashi Maemura
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - Jie E Yang
- Department of Biochemistry, University of Wisconsin, Madison, WI, USA
- Cryo-EM Research Center, Department of Biochemistry, University of Wisconsin, Madison, WI, USA
| | - Elizabeth R Wright
- Department of Biochemistry, University of Wisconsin, Madison, WI, USA
- Cryo-EM Research Center, Department of Biochemistry, University of Wisconsin, Madison, WI, USA
| | - Yoshihiro Kawaoka
- Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA.
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
| | - Ravi S Kane
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
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15
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Application of Advanced Light Microscopy to the Study of HIV and Its Interactions with the Host. Viruses 2021; 13:v13020223. [PMID: 33535486 PMCID: PMC7912744 DOI: 10.3390/v13020223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/24/2022] Open
Abstract
This review highlights the significant observations of human immunodeficiency virus (HIV) assembly, release and maturation made possible with advanced light microscopy techniques. The advances in technology which now enables these light microscopy measurements are discussed with special emphasis on live imaging approaches including Total Internal Reflection Fluorescence (TIRF), high-resolution light microscopy techniques including PALM and STORM and single molecule measurements, including Fluorescence Resonance Energy Transfer (FRET). The review concludes with a discussion on what new insights and understanding can be expected from these measurements.
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16
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Rūmnieks J, Liekniņa I, Kalniņš G, Šišovs M, Akopjana I, Bogans J, Tārs K. Three-dimensional structure of 22 uncultured ssRNA bacteriophages: Flexibility of the coat protein fold and variations in particle shapes. SCIENCE ADVANCES 2020; 6:6/36/eabc0023. [PMID: 32917600 PMCID: PMC7467689 DOI: 10.1126/sciadv.abc0023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
The single-stranded RNA (ssRNA) bacteriophages are among the simplest known viruses with small genomes and exceptionally high mutation rates. The number of ssRNA phage isolates has remained very low, but recent metagenomic studies have uncovered an immense variety of distinct uncultured ssRNA phages. The coat proteins (CPs) in these genomes are particularly diverse, with notable variation in length and often no recognizable similarity to previously known viruses. We recombinantly expressed metagenome-derived ssRNA phage CPs to produce virus-like particles and determined the three-dimensional structure of 22 previously uncharacterized ssRNA phage capsids covering nine distinct CP types. The structures revealed substantial deviations from the previously known ssRNA phage CP fold, uncovered an unusual prolate particle shape, and revealed a previously unseen dsRNA binding mode. These data expand our knowledge of the evolution of viral structural proteins and are of relevance for applications such as ssRNA phage-based vaccine design.
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Affiliation(s)
- Jānis Rūmnieks
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067, Riga, Latvia
| | - Ilva Liekniņa
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067, Riga, Latvia
| | - Gints Kalniņš
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067, Riga, Latvia
| | - Mihails Šišovs
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067, Riga, Latvia
| | - Ināra Akopjana
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067, Riga, Latvia
| | - Jānis Bogans
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067, Riga, Latvia
| | - Kaspars Tārs
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067, Riga, Latvia.
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17
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Gorzelnik KV, Zhang J. Cryo-EM reveals infection steps of single-stranded RNA bacteriophages. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 160:79-86. [PMID: 32841651 DOI: 10.1016/j.pbiomolbio.2020.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/23/2020] [Accepted: 07/26/2020] [Indexed: 02/07/2023]
Abstract
Single-stranded RNA bacteriophages (ssRNA phages) are small spherical RNA viruses that infect bacteria with retractile pili. The single positive-sense genomic RNA of ssRNA phages, which is protected by a capsid shell, is delivered into the host via the retraction of the host pili. Structures involved in ssRNA phage infection cycle are essential for understanding the underlying mechanisms that can be used to engineer them for therapeutic applications. This review summarizes the recent breakthroughs in high-resolution structural studies of two ssRNA phages, MS2 and Qβ, and their interaction with the host, E. coli, by cryo-electron microscopy (cryo-EM). These studies revealed new cryo-EM structures, which provide insights into how MS2 and Qβ package the RNA, lyse E. coli, and adsorb to the receptor F-pili, responsible for conjugation. Methodologies described here can be expanded to study other ssRNA phages that target pathogenic bacteria.
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Affiliation(s)
- Karl Victor Gorzelnik
- Department of Biochemistry and Biophysics, Center for Phage Technology, Texas A&M University, College Station, TX, 77843, USA
| | - Junjie Zhang
- Department of Biochemistry and Biophysics, Center for Phage Technology, Texas A&M University, College Station, TX, 77843, USA.
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18
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Meir M, Harel N, Miller D, Gelbart M, Eldar A, Gophna U, Stern A. Competition between social cheater viruses is driven by mechanistically different cheating strategies. SCIENCE ADVANCES 2020; 6:eabb7990. [PMID: 32937370 PMCID: PMC7442481 DOI: 10.1126/sciadv.abb7990] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 07/09/2020] [Indexed: 05/09/2023]
Abstract
Cheater viruses, also known as defective interfering viruses, cannot replicate on their own yet replicate faster than the wild type upon coinfection. While there is growing interest in using cheaters as antiviral therapeutics, the mechanisms underlying cheating have been rarely explored. During experimental evolution of MS2 phage, we observed the parallel emergence of two independent cheater mutants. The first, a point deletion mutant, lacked polymerase activity but was advantageous in viral packaging. The second synonymous mutant cheater displayed a completely different cheating mechanism, involving an altered RNA structure. Continued evolution revealed the demise of the deletion cheater and rise of the synonymous cheater. A mathematical model inferred that while a single cheater is expected to reach an equilibrium with the wild type, cheater demise arises from antagonistic interactions between coinfecting cheaters. These findings highlight layers of parasitism: viruses parasitizing cells, cheaters parasitizing intact viruses, and cheaters may parasitize other cheaters.
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Affiliation(s)
- Moran Meir
- School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
| | - Noam Harel
- School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
| | - Danielle Miller
- School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
| | - Maoz Gelbart
- School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
| | - Avigdor Eldar
- School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel
| | - Uri Gophna
- School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel.
| | - Adi Stern
- School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel.
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19
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Pandey S, Gravel CM, Stockert OM, Wang CD, Hegner CL, LeBlanc H, Berry KE. Genetic identification of the functional surface for RNA binding by Escherichia coli ProQ. Nucleic Acids Res 2020; 48:4507-4520. [PMID: 32170306 PMCID: PMC7192607 DOI: 10.1093/nar/gkaa144] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/20/2020] [Accepted: 02/24/2020] [Indexed: 12/17/2022] Open
Abstract
The FinO-domain-protein ProQ is an RNA-binding protein that has been known to play a role in osmoregulation in proteobacteria. Recently, ProQ has been shown to act as a global RNA-binding protein in Salmonella and Escherichia coli, binding to dozens of small RNAs (sRNAs) and messenger RNAs (mRNAs) to regulate mRNA-expression levels through interactions with both 5′ and 3′ untranslated regions (UTRs). Despite excitement around ProQ as a novel global RNA-binding protein, and its potential to serve as a matchmaking RNA chaperone, significant gaps remain in our understanding of the molecular mechanisms ProQ uses to interact with RNA. In order to apply the tools of molecular genetics to this question, we have adapted a bacterial three-hybrid (B3H) assay to detect ProQ’s interactions with target RNAs. Using domain truncations, site-directed mutagenesis and an unbiased forward genetic screen, we have identified a group of highly conserved residues on ProQ’s NTD as the primary face for in vivo recognition of two RNAs, and propose that the NTD structure serves as an electrostatic scaffold to recognize the shape of an RNA duplex.
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Affiliation(s)
- Smriti Pandey
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Chandra M Gravel
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Oliver M Stockert
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Clara D Wang
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Courtney L Hegner
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Hannah LeBlanc
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA
| | - Katherine E Berry
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA.,Department of Chemistry, Mount Holyoke College, South Hadley, MA 01075, USA
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20
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Janowski R, Niessing D. The large family of PC4-like domains - similar folds and functions throughout all kingdoms of life. RNA Biol 2020; 17:1228-1238. [PMID: 32476604 PMCID: PMC7549692 DOI: 10.1080/15476286.2020.1761639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RNA- and DNA-binding domains are essential building blocks for specific regulation of gene expression. While a number of canonical nucleic acid binding domains share sequence and structural conservation, others are less obviously linked by evolutionary traits. In this review, we describe a protein fold of about 150 aa in length, bearing a conserved β-β-β-β-α-linker-β-β-β-β-α topology and similar nucleic acid binding properties but no apparent sequence conservation. The same overall fold can also be achieved by dimerization of two proteins, each bearing a β-β-β-β-α topology. These proteins include but are not limited to the transcription factors PC4 and P24 from humans and plants, respectively, the human RNA-transport factor Pur-α (also termed PURA), as well as the ssDNA-binding SP_0782 protein from Streptococcus pneumonia and the bacteriophage coat proteins PP7 and MS2. Besides their common overall topology, these proteins share common nucleic acids binding surfaces and thus functional similarity. We conclude that these PC4-like domains include proteins from all kingdoms of life and are much more abundant than previously known.
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Affiliation(s)
- Robert Janowski
- Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health , Neuherberg, Germany
| | - Dierk Niessing
- Institute of Structural Biology, Helmholtz Zentrum München - German Research Center for Environmental Health , Neuherberg, Germany.,Institute of Pharmaceutical Biotechnology, Ulm University , Ulm, Germany
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21
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Rosenbach H, Victor J, Borggräfe J, Biehl R, Steger G, Etzkorn M, Span I. Expanding crystallization tools for nucleic acid complexes using U1A protein variants. J Struct Biol 2020; 210:107480. [PMID: 32070773 DOI: 10.1016/j.jsb.2020.107480] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/04/2020] [Accepted: 02/14/2020] [Indexed: 11/24/2022]
Abstract
The major bottlenecks in structure elucidation of nucleic acids are crystallization and phasing. Co-crystallization with proteins is a straight forward approach to overcome these challenges. The human RNA-binding protein U1A has previously been established as crystallization module, however, the absence of UV-active residues and the predetermined architecture in the asymmetric unit constitute clear limitations of the U1A system. Here, we report three crystal structures of tryptophan-containing U1A variants, which expand the crystallization toolbox for nucleic acids. Analysis of the structures complemented by SAXS, NMR spectroscopy, and optical spectroscopy allow for insights into the potential of the U1A variants to serve as crystallization modules for nucleic acids. In addition, we report a fast and efficient protocol for crystallization of RNA by soaking and present a fluorescence-based approach for detecting RNA-binding in crystallo. Our results provide a new tool set for the crystallization of RNA and RNA:DNA complexes.
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Affiliation(s)
- Hannah Rosenbach
- Institut für Physikalische Biologie, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstrasse 1, 40225 Duesseldorf, Germany.
| | - Julian Victor
- Institut für Physikalische Biologie, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstrasse 1, 40225 Duesseldorf, Germany.
| | - Jan Borggräfe
- Institut für Physikalische Biologie, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstrasse 1, 40225 Duesseldorf, Germany; Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany.
| | - Ralf Biehl
- Jülich Centre for Neutron Science (JCNS-1/ICS-1), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany.
| | - Gerhard Steger
- Institut für Physikalische Biologie, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstrasse 1, 40225 Duesseldorf, Germany.
| | - Manuel Etzkorn
- Institut für Physikalische Biologie, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstrasse 1, 40225 Duesseldorf, Germany; Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany.
| | - Ingrid Span
- Institut für Physikalische Biologie, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstrasse 1, 40225 Duesseldorf, Germany.
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22
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Abstract
ssRNA phages belonging to the family Leviviridae are among the tiniest viruses, infecting various Gram-negative bacteria by adsorption to their pilus structures. Due to their simplicity, they have been intensively studied as models for understanding various problems in molecular biology and virology. Several of the studied ssRNA characteristics, such as coat protein–RNA interactions and the ability to readily form virus-like particles in recombinant expression systems, have fueled many practical applications such as RNA labeling and tracking systems and vaccine development. In this chapter, we review the life cycle, structure and applications of these small yet fascinating viruses.
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Latallo MJ, Livingston NM, Wu B. Translation imaging of single mRNAs in established cell lines and primary cultured neurons. Methods 2019; 162-163:12-22. [PMID: 30905747 DOI: 10.1016/j.ymeth.2019.03.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 03/17/2019] [Accepted: 03/20/2019] [Indexed: 12/28/2022] Open
Abstract
The central dogma of molecular biology reaches a crescendo at its final step: the translation of an mRNA into its corresponding protein product. This process is highly regulated both spatially and temporally, requiring techniques to interrogate the subcellular translational status of mRNAs in both living and fixed cells. Single-molecule imaging of nascent peptides (SINAPs) and related techniques allow us to study this fundamental process for single mRNAs in live cells. These techniques enable researchers to address previously intractable questions in the central dogma, such as the origin of stochastic translational control and the role of local translation in highly polarized cells. In this review, we present the methodology and the theoretical framework for conducting studies using SINAPs in both established cell lines and primary cultured neurons.
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Affiliation(s)
- Malgorzata J Latallo
- Johns Hopkins School of Medicine, Department of Biophysics and Biophysical Chemistry, 855 N Wolfe Street Ste. 454, Baltimore, MD 21205, USA; Johns Hopkins School of Medicine, Center for Cell Dynamics, Baltimore, USA
| | - Nathan M Livingston
- Johns Hopkins School of Medicine, Department of Biophysics and Biophysical Chemistry, 855 N Wolfe Street Ste. 454, Baltimore, MD 21205, USA; Johns Hopkins School of Medicine, Center for Cell Dynamics, Baltimore, USA
| | - Bin Wu
- Johns Hopkins School of Medicine, Department of Biophysics and Biophysical Chemistry, 855 N Wolfe Street Ste. 454, Baltimore, MD 21205, USA; Johns Hopkins School of Medicine, Center for Cell Dynamics, Baltimore, USA; Johns Hopkins School of Medicine, Solomon H. Snyder Department of Neuroscience, Baltimore, USA.
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24
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Liekniņa I, Kalniņš G, Akopjana I, Bogans J, Šišovs M, Jansons J, Rūmnieks J, Tārs K. Production and characterization of novel ssRNA bacteriophage virus-like particles from metagenomic sequencing data. J Nanobiotechnology 2019; 17:61. [PMID: 31084612 PMCID: PMC6513524 DOI: 10.1186/s12951-019-0497-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/04/2019] [Indexed: 12/30/2022] Open
Abstract
Background Protein shells assembled from viral coat proteins are an attractive platform for development of new vaccines and other tools such as targeted bioimaging and drug delivery agents. Virus-like particles (VLPs) derived from the single-stranded RNA (ssRNA) bacteriophage coat proteins (CPs) have been important and successful contenders in the area due to their simplicity and robustness. However, only a few different VLP types are available that put certain limitations on continued developments and expanded adaptation of ssRNA phage VLP technology. Metagenomic studies have been a rich source for discovering novel viral sequences, and in recent years have unraveled numerous ssRNA phage genomes significantly different from those known before. Here, we describe the use of ssRNA CP sequences found in metagenomic data to experimentally produce and characterize novel VLPs. Results Approximately 150 ssRNA phage CP sequences were sourced from metagenomic sequence data and grouped into 14 different clusters based on CP sequence similarity analysis. 110 CP-encoding sequences were obtained by gene synthesis and expressed in bacteria which in 80 cases resulted in VLP assembly. Production and purification of the VLPs was straightforward and compatible with established protocols, with the only exception that a considerable proportion of the CPs had to be produced at a lower temperature to ensure VLP assembly. The VLP morphology was similar to that of the previously studied phages, although a few deviations such as elongated or smaller particles were noted in certain cases. In addition, stabilizing inter-subunit disulfide bonds were detected in six VLPs and several possible candidate RNA structures in the phage genomes were identified that might bind to the coat protein and ensure specific RNA packaging. Conclusions Compared to the few types of ssRNA phage VLPs that were used before, several dozens of new particles representing ten distinct similarity groups are now available with a notable potential for biotechnological applications. It is believed that the novel VLPs described in this paper will provide the groundwork for future development of new vaccines and other applications based on ssRNA bacteriophage VLPs. Electronic supplementary material The online version of this article (10.1186/s12951-019-0497-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ilva Liekniņa
- Latvian Biomedical Research and Study Center, Rātsupītes 1, Riga, LV1067, Latvia
| | - Gints Kalniņš
- Latvian Biomedical Research and Study Center, Rātsupītes 1, Riga, LV1067, Latvia
| | - Ināra Akopjana
- Latvian Biomedical Research and Study Center, Rātsupītes 1, Riga, LV1067, Latvia
| | - Jānis Bogans
- Latvian Biomedical Research and Study Center, Rātsupītes 1, Riga, LV1067, Latvia
| | - Mihails Šišovs
- Latvian Biomedical Research and Study Center, Rātsupītes 1, Riga, LV1067, Latvia
| | - Juris Jansons
- Latvian Biomedical Research and Study Center, Rātsupītes 1, Riga, LV1067, Latvia
| | - Jānis Rūmnieks
- Latvian Biomedical Research and Study Center, Rātsupītes 1, Riga, LV1067, Latvia
| | - Kaspars Tārs
- Latvian Biomedical Research and Study Center, Rātsupītes 1, Riga, LV1067, Latvia.
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25
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Twarock R, Stockley PG. RNA-Mediated Virus Assembly: Mechanisms and Consequences for Viral Evolution and Therapy. Annu Rev Biophys 2019; 48:495-514. [PMID: 30951648 PMCID: PMC7612295 DOI: 10.1146/annurev-biophys-052118-115611] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Viruses, entities composed of nucleic acids, proteins, and in some cases lipids lack the ability to replicate outside their target cells. Their components self-assemble at the nanoscale with exquisite precision-a key to their biological success in infection. Recent advances in structure determination and the development of biophysical tools such as single-molecule spectroscopy and noncovalent mass spectrometry allow unprecedented access to the detailed assembly mechanisms of simple virions. Coupling these techniques with mathematical modeling and bioinformatics has uncovered a previously unsuspected role for genomic RNA in regulating formation of viral capsids, revealing multiple, dispersed RNA sequence/structure motifs [packaging signals (PSs)] that bind cognate coat proteins cooperatively. The PS ensemble controls assembly efficiency and accounts for the packaging specificity seen in vivo. The precise modes of action of the PSs vary between viral families, but this common principle applies across many viral families, including major human pathogens. These insights open up the opportunity to block or repurpose PS function in assembly for both novel antiviral therapy and gene/drug/vaccine applications.
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Affiliation(s)
- Reidun Twarock
- Departments of Mathematics and Biology, and York Cross-disciplinary Centre for Systems Analysis, University of York, York YO10 5GE, United Kingdom;
| | - Peter G Stockley
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom;
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26
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Seo JS, Chua NH. Trimolecular Fluorescence Complementation (TriFC) Assay for Visualization of RNA-Protein Interaction in Plants. Methods Mol Biol 2019; 1933:297-303. [PMID: 30945194 DOI: 10.1007/978-1-4939-9045-0_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
RNA-protein interactions play important roles in various eukaryotic biological processes. Molecular imaging of subcellular localization of RNA-protein complexes in plants is critical for understanding these interactions. However, methods to image RNA-protein interactions in living plants have not yet been developed until now. Recently, we have developed a trimolecular fluorescence complementation (TriFC) system for in vivo visualization of RNA-protein interaction by transient expression in tobacco leaves. In this method, we combined conventional bimolecular fluorescence complementation (BiFC) system with the MS2 system (phage MS2 coat protein [MCP] and its binding RNA sequence [MS2 sequence]) to tag lncRNA. Target RNA is tagged with 6xMS2, and MCP and RNA-binding protein are fused with YFP fragments. DNA constructs encoding such fusion RNA and proteins are infiltrated into tobacco leaves with Agrobacterium suspensions. RNA-protein interaction in vivo is observed by confocal microscopy.
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Affiliation(s)
- Jun Sung Seo
- Laboratory of Plant Molecular Biology, Rockefeller University, New York, NY, USA
- TEMASEK Life Sciences Laboratory, Singapore, Singapore
| | - Nam-Hai Chua
- Laboratory of Plant Molecular Biology, Rockefeller University, New York, NY, USA.
- TEMASEK Life Sciences Laboratory, Singapore, Singapore.
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27
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Ramesh R, Lim XX, Raghuvamsi PV, Wu C, Wong SM, Anand GS. Uncovering metastability and disassembly hotspots in whole viral particles. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 143:5-12. [PMID: 30553754 DOI: 10.1016/j.pbiomolbio.2018.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/26/2018] [Accepted: 12/12/2018] [Indexed: 01/18/2023]
Abstract
Viruses are metastable macromolecular assemblies that toggle between multiple conformational states through molecular rearrangements that are critical for mediating viral host entry. Viruses respond to different host specific environmental cues to form disassembly intermediates for the eventual release of genomic material required for replication. Although static snapshots of these intermediates have been captured through structural techniques such as X-ray crystallography and cryo-EM, the mechanistic details of these conformational rearrangements underpinning viral metastability have been poorly understood. Amide hydrogen deuterium exchange mass spectrometry (HDXMS) is a powerful tool that measures hydrogen bonding propensities to probe changes in the dynamics of different macromolecular interactions. Chaotropic agents such as urea can be used to disrupt hydrogen bonds between different subunits, thereby ranking regions of the virus that are critical in maintaining viral stability. By controlled urea denaturation with HDXMS, we have identified specific loci in a Turnip Crinkle Virus (TCV) model showing increased deuterium exchange with even minimally disruptive concentrations of urea. These loci represent dynamic disassembly hotspots. These hotspots are predominantly present at the quaternary contacts at the 3-fold and 5-fold axes. This approach can be applied to detect vulnerabilities in virus icosahedral structures to uncover the molecular mechanism of viral disassembly.
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Affiliation(s)
- Ranita Ramesh
- Department of Biological Sciences, National University of Singapore, 117543, Singapore
| | - Xin Xiang Lim
- Department of Biological Sciences, National University of Singapore, 117543, Singapore
| | | | - Chao Wu
- Department of Biological Sciences, National University of Singapore, 117543, Singapore
| | - Sek Man Wong
- Department of Biological Sciences, National University of Singapore, 117543, Singapore; Temasek Life Sciences Laboratory, Singapore, 117604, Singapore
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28
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Tutucci E, Vera M, Singer RH. Single-mRNA detection in living S. cerevisiae using a re-engineered MS2 system. Nat Protoc 2018; 13:2268-2296. [DOI: 10.1038/s41596-018-0037-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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29
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Twarock R, Bingham RJ, Dykeman EC, Stockley PG. A modelling paradigm for RNA virus assembly. Curr Opin Virol 2018; 31:74-81. [PMID: 30078702 PMCID: PMC6281560 DOI: 10.1016/j.coviro.2018.07.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 07/04/2018] [Indexed: 12/14/2022]
Abstract
Virus assembly, a key stage in any viral life cycle, had long been considered to be primarily driven by protein-protein interactions and nonspecific interactions between genomic RNA and capsid protein. We review here a modelling paradigm for RNA virus assembly that illustrates the crucial roles of multiple dispersed, specific interactions between viral genomes and coat proteins in capsid assembly. The model reveals how multiple sequence-structure motifs in the genomic RNA, termed packaging signals, with a shared coat protein recognition motif enable viruses to overcome a viral assembly-equivalent of Levinthal's Paradox in protein folding. The fitness advantages conferred by this mechanism suggest that it should be widespread in viruses, opening up new perspectives on viral evolution and anti-viral therapy.
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Affiliation(s)
- Reidun Twarock
- York Centre for Cross-disciplinary Systems Analysis, University of York, York YO10 5GE, UK; Department of Mathematics, University of York, York YO10 5DD, UK; Department of Biology, University of York, York YO10 5NG, UK.
| | - Richard J Bingham
- York Centre for Cross-disciplinary Systems Analysis, University of York, York YO10 5GE, UK; Department of Mathematics, University of York, York YO10 5DD, UK; Department of Biology, University of York, York YO10 5NG, UK
| | - Eric C Dykeman
- York Centre for Cross-disciplinary Systems Analysis, University of York, York YO10 5GE, UK; Department of Mathematics, University of York, York YO10 5DD, UK
| | - Peter G Stockley
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT UK
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30
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Callanan J, Stockdale SR, Shkoporov A, Draper LA, Ross RP, Hill C. RNA Phage Biology in a Metagenomic Era. Viruses 2018; 10:E386. [PMID: 30037084 PMCID: PMC6071253 DOI: 10.3390/v10070386] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/22/2022] Open
Abstract
The number of novel bacteriophage sequences has expanded significantly as a result of many metagenomic studies of phage populations in diverse environments. Most of these novel sequences bear little or no homology to existing databases (referred to as the "viral dark matter"). Also, these sequences are primarily derived from DNA-encoded bacteriophages (phages) with few RNA phages included. Despite the rapid advancements in high-throughput sequencing, few studies enrich for RNA viruses, i.e., target viral rather than cellular fraction and/or RNA rather than DNA via a reverse transcriptase step, in an attempt to capture the RNA viruses present in a microbial communities. It is timely to compile existing and relevant information about RNA phages to provide an insight into many of their important biological features, which should aid in sequence-based discovery and in their subsequent annotation. Without comprehensive studies, the biological significance of RNA phages has been largely ignored. Future bacteriophage studies should be adapted to ensure they are properly represented in phageomic studies.
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Affiliation(s)
- Julie Callanan
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
- School of Microbiology, University College Cork, Cork, T12 YN60, Ireland.
| | - Stephen R Stockdale
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, P61 C996, Ireland.
| | - Andrey Shkoporov
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
| | - Lorraine A Draper
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
- School of Microbiology, University College Cork, Cork, T12 YN60, Ireland.
| | - R Paul Ross
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
- School of Microbiology, University College Cork, Cork, T12 YN60, Ireland.
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, P61 C996, Ireland.
| | - Colin Hill
- APC Microbiome Ireland, University College Cork, Cork, T12 YT20, Ireland.
- School of Microbiology, University College Cork, Cork, T12 YN60, Ireland.
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31
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Twarock R, Leonov G, Stockley PG. Hamiltonian path analysis of viral genomes. Nat Commun 2018; 9:2021. [PMID: 29789600 PMCID: PMC5964074 DOI: 10.1038/s41467-018-03713-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 03/02/2018] [Indexed: 12/25/2022] Open
Affiliation(s)
- Reidun Twarock
- York Cross-disciplinary Centre for Systems Analysis, University of York, York, YO10 5DD, UK.
- Departments of Mathematics and Biology, University of York, York, YO10 5DD, UK.
| | - German Leonov
- York Cross-disciplinary Centre for Systems Analysis, University of York, York, YO10 5DD, UK
- Departments of Mathematics and Biology, University of York, York, YO10 5DD, UK
| | - Peter G Stockley
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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32
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Intrinsically-disordered N-termini in human parechovirus 1 capsid proteins bind encapsidated RNA. Sci Rep 2018; 8:5820. [PMID: 29643409 PMCID: PMC5895611 DOI: 10.1038/s41598-018-23552-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 03/15/2018] [Indexed: 12/22/2022] Open
Abstract
Human parechoviruses (HPeV) are picornaviruses with a highly-ordered RNA genome contained within icosahedrally-symmetric capsids. Ordered RNA structures have recently been shown to interact with capsid proteins VP1 and VP3 and facilitate virus assembly in HPeV1. Using an assay that combines reversible cross-linking, RNA affinity purification and peptide mass fingerprinting (RCAP), we mapped the RNA-interacting regions of the capsid proteins from the whole HPeV1 virion in solution. The intrinsically-disordered N-termini of capsid proteins VP1 and VP3, and unexpectedly, VP0, were identified to interact with RNA. Comparing these results to those obtained using recombinantly-expressed VP0 and VP1 confirmed the virion binding regions, and revealed unique RNA binding regions in the isolated VP0 not previously observed in the crystal structure of HPeV1. We used RNA fluorescence anisotropy to confirm the RNA-binding competency of each of the capsid proteins’ N-termini. These findings suggests that dynamic interactions between the viral RNA and the capsid proteins modulate virus assembly, and suggest a novel role for VP0.
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33
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Shrimp JH, Grose C, Widmeyer SRT, Thorpe AL, Jadhav A, Meier JL. Chemical Control of a CRISPR-Cas9 Acetyltransferase. ACS Chem Biol 2018; 13:455-460. [PMID: 29309117 PMCID: PMC6320253 DOI: 10.1021/acschembio.7b00883] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Lysine acetyltransferases (KATs) play a critical role in the regulation of transcription and other genomic functions. However, a persistent challenge is the development of assays capable of defining KAT activity directly in living cells. Toward this goal, here we report the application of a previously reported dCas9-p300 fusion as a transcriptional reporter of KAT activity. First, we benchmark the activity of dCas9-p300 relative to other dCas9-based transcriptional activators and demonstrate its compatibility with second generation short guide RNA architectures. Next, we repurpose this technology to rapidly identify small molecule inhibitors of acetylation-dependent gene expression. These studies validate a recently reported p300 inhibitor chemotype and reveal a role for p300s bromodomain in dCas9-p300-mediated transcriptional activation. Comparison with other CRISPR-Cas9 transcriptional activators highlights the inherent ligand tunable nature of dCas9-p300 fusions, suggesting new opportunities for orthogonal gene expression control. Overall, our studies highlight dCas9-p300 as a powerful tool for studying gene expression mechanisms in which acetylation plays a causal role and provide a foundation for future applications requiring spatiotemporal control over acetylation at specific genomic loci.
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Affiliation(s)
- Jonathan H Shrimp
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Frederick, Maryland 21702, United States
| | - Carissa Grose
- Protein Expression Laboratory, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc. , Frederick, Maryland 21702, United States
| | - Stephanie R T Widmeyer
- Protein Expression Laboratory, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc. , Frederick, Maryland 21702, United States
| | - Abigail L Thorpe
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Frederick, Maryland 21702, United States
| | - Ajit Jadhav
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health , Rockville, Maryland 20850, United States
| | - Jordan L Meier
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Frederick, Maryland 21702, United States
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34
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Berry KE, Hochschild A. A bacterial three-hybrid assay detects Escherichia coli Hfq-sRNA interactions in vivo. Nucleic Acids Res 2018; 46:e12. [PMID: 29140461 PMCID: PMC5778611 DOI: 10.1093/nar/gkx1086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/21/2017] [Accepted: 10/20/2017] [Indexed: 01/08/2023] Open
Abstract
The interaction of RNA molecules with proteins is a critical aspect of gene regulation across all domains of life. Here, we report the development of a bacterial three-hybrid (B3H) assay to genetically detect RNA-protein interactions. The basis for this three-hybrid assay is a transcription-based bacterial two-hybrid assay that has been used widely to detect and dissect protein-protein interactions. In the three-hybrid assay, a DNA-bound protein with a fused RNA-binding moiety (the coat protein of bacteriophage MS2 (MS2CP)) is used to recruit a hybrid RNA upstream of a test promoter. The hybrid RNA consists of a constant region that binds the tethered MS2CP and a variable region. Interaction between the variable region of the hybrid RNA and a target RNA-binding protein that is fused to a subunit of Escherichia coli RNA polymerase (RNAP) stabilizes the binding of RNAP to the test promoter, thereby activating transcription of a reporter gene. We demonstrate that this three-hybrid assay detects interaction between non-coding small RNAs (sRNAs) and the hexameric RNA chaperone Hfq from E. coli and enables the identification of Hfq mutants with sRNA-binding defects. Our findings suggest that this B3H assay will be broadly applicable for the study of RNA-protein interactions.
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Affiliation(s)
- Katherine E Berry
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Ann Hochschild
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
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35
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Abstract
Bacteriophages of the Leviviridae family are small viruses with short single-stranded RNA (ssRNA) genomes. Protein-RNA interactions play a key role throughout the phage life cycle, and all of the conserved phage proteins - the maturation protein, the coat protein and the replicase - are able to recognize specific structures in the RNA genome. The phage-coded replicase subunit associates with several host proteins to form a catalytically active complex. Recognition of the genomic RNA by the replicase complex is achieved in a remarkably complex manner that exploits the RNA-binding properties of host proteins and the particular three-dimensional structure of the phage genome. The coat protein recognizes a hairpin structure at the beginning of the replicase gene. The binding interaction serves to regulate the expression of the replicase gene and can be remarkably different in various ssRNA phages. The maturation protein is a minor structural component of the virion that binds to the genome, mediates attachment to the host and guides the genome into the cell. The maturation protein has two distinct RNA-binding surfaces that are in contact with different regions of the genome. The maturation and coat proteins also work together to ensure the encapsidation of the phage genome in new virus particles. In this chapter, the different ssRNA phage protein-RNA interactions, as well as some of their practical applications, are discussed in detail.
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Affiliation(s)
| | - Kaspars Tārs
- Biomedical Research and Study Center, Riga, Latvia.
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36
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In situ structures of the genome and genome-delivery apparatus in a single-stranded RNA virus. Nature 2016; 541:112-116. [PMID: 27992877 PMCID: PMC5701785 DOI: 10.1038/nature20589] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/26/2016] [Indexed: 12/11/2022]
Abstract
Genome packaging into a protein capsid and its subsequent delivery into a host cell are two fundamental processes in the life cycle of a virus. Unlike dsDNA viruses which pump their genome into a preformed capsid1-3, ssRNA viruses, such as bacteriophage MS2, co-assemble their capsid with genome4-7; however, the structural basis of this co-assembly is poorly understood. MS2 infects Escherichia coli via host “sex” pilus (F-pilus)8 and is the first fully-sequenced organism9 and a model system for studies of gene translational regulations10,11, RNA-protein interactions12-14, and RNA virus assembly15-17. Its positive-sense ssRNA genome of 3569 bases is enclosed in a capsid with one maturation protein (MP) monomer and 89 coat protein (CP) dimers arranged in a T=3 icosahedral lattice18,19. MP is responsible for attaching the virus to an F-pilus and delivering the viral genome into the host during infection8, but how the genome is organized and delivered are not known. Here we show the MS2 structure at 3.6Å resolution determined by electron-counting cryo electron microscopy (cryoEM) and asymmetric reconstruction. We traced ~80% backbone of the viral genome, built atomic models for 16 RNA stem-loops, and identified three conserved motifs of RNA-CP interactions among 15 of these stem-loops with diverse sequences. The stem-loop at 3’ end of the genome interacts extensively with the MP, which, with just a six-helix bundle and a six-stranded β-sheet, forms a genome-delivery apparatus, and joins 89 CP-dimers to form a capsid. This first atomic description of genome-capsid interactions in a spherical ssRNA virus provides insights into genome delivery via host “sex” pilus and mechanisms underlying ssRNA-capsid co-assembly, and inspires imaginations about links between nucleoprotein complexes and the origin of viruses.
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Pumpens P, Renhofa R, Dishlers A, Kozlovska T, Ose V, Pushko P, Tars K, Grens E, Bachmann MF. The True Story and Advantages of RNA Phage Capsids as Nanotools. Intervirology 2016; 59:74-110. [DOI: 10.1159/000449503] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/30/2016] [Indexed: 11/19/2022] Open
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38
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He C, Sidoli S, Warneford-Thomson R, Tatomer DC, Wilusz JE, Garcia BA, Bonasio R. High-Resolution Mapping of RNA-Binding Regions in the Nuclear Proteome of Embryonic Stem Cells. Mol Cell 2016; 64:416-430. [PMID: 27768875 PMCID: PMC5222606 DOI: 10.1016/j.molcel.2016.09.034] [Citation(s) in RCA: 191] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/30/2016] [Accepted: 09/23/2016] [Indexed: 12/21/2022]
Abstract
Interactions between noncoding RNAs and chromatin proteins play important roles in gene regulation, but the molecular details of most of these interactions are unknown. Using protein-RNA photocrosslinking and mass spectrometry on embryonic stem cell nuclei, we identified and mapped, at peptide resolution, the RNA-binding regions in ∼800 known and previously unknown RNA-binding proteins, many of which are transcriptional regulators and chromatin modifiers. In addition to known RNA-binding motifs, we detected several protein domains previously unknown to function in RNA recognition, as well as non-annotated and/or disordered regions, suggesting that many functional protein-RNA contacts remain unexplored. We identified RNA-binding regions in several chromatin regulators, including TET2, and validated their ability to bind RNA. Thus, proteomic identification of RNA-binding regions (RBR-ID) is a powerful tool to map protein-RNA interactions and will allow rational design of mutants to dissect their function at a mechanistic level.
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Affiliation(s)
- Chongsheng He
- Epigenetics Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Simone Sidoli
- Epigenetics Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert Warneford-Thomson
- Epigenetics Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Graduate Group in Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Deirdre C Tatomer
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jeremy E Wilusz
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Benjamin A Garcia
- Epigenetics Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Roberto Bonasio
- Epigenetics Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Gorzelnik KV, Cui Z, Reed CA, Jakana J, Young R, Zhang J. Asymmetric cryo-EM structure of the canonical Allolevivirus Qβ reveals a single maturation protein and the genomic ssRNA in situ. Proc Natl Acad Sci U S A 2016; 113:11519-11524. [PMID: 27671640 PMCID: PMC5068298 DOI: 10.1073/pnas.1609482113] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Single-stranded (ss) RNA viruses infect all domains of life. To date, for most ssRNA virions, only the structures of the capsids and their associated protein components have been resolved to high resolution. Qβ, an ssRNA phage specific for the conjugative F-pilus, has a T = 3 icosahedral lattice of coat proteins assembled around its 4,217 nucleotides of genomic RNA (gRNA). In the mature virion, the maturation protein, A2, binds to the gRNA and is required for adsorption to the F-pilus. Here, we report the cryo-electron microscopy (cryo-EM) structures of Qβ with and without symmetry applied. The icosahedral structure, at 3.7-Å resolution, resolves loops not previously seen in the published X-ray structure, whereas the asymmetric structure, at 7-Å resolution, reveals A2 and the gRNA. A2 contains a bundle of α-helices and replaces one dimer of coat proteins at a twofold axis. The helix bundle binds gRNA, causing denser packing of RNA in its proximity, which asymmetrically expands the surrounding coat protein shell to potentially facilitate RNA release during infection. We observe a fixed pattern of gRNA organization among all viral particles, with the major and minor grooves of RNA helices clearly visible. A single layer of RNA directly contacts every copy of the coat protein, with one-third of the interactions occurring at operator-like RNA hairpins. These RNA-coat interactions stabilize the tertiary structure of gRNA within the virion, which could further provide a roadmap for capsid assembly.
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Affiliation(s)
- Karl V Gorzelnik
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
| | - Zhicheng Cui
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
| | - Catrina A Reed
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
| | - Joanita Jakana
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - Ry Young
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
| | - Junjie Zhang
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843;
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40
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Abeydeera ND, Egli M, Cox N, Mercier K, Conde JN, Pallan PS, Mizurini DM, Sierant M, Hibti FE, Hassell T, Wang T, Liu FW, Liu HM, Martinez C, Sood AK, Lybrand TP, Frydman C, Monteiro RQ, Gomer RH, Nawrot B, Yang X. Evoking picomolar binding in RNA by a single phosphorodithioate linkage. Nucleic Acids Res 2016; 44:8052-64. [PMID: 27566147 PMCID: PMC5041495 DOI: 10.1093/nar/gkw725] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/02/2016] [Accepted: 08/06/2016] [Indexed: 11/12/2022] Open
Abstract
RNA aptamers are synthetic oligonucleotide-based affinity molecules that utilize unique three-dimensional structures for their affinity and specificity to a target such as a protein. They hold the promise of numerous advantages over biologically produced antibodies; however, the binding affinity and specificity of RNA aptamers are often insufficient for successful implementation in diagnostic assays or as therapeutic agents. Strong binding affinity is important to improve the downstream applications. We report here the use of the phosphorodithioate (PS2) substitution on a single nucleotide of RNA aptamers to dramatically improve target binding affinity by ∼1000-fold (from nanomolar to picomolar). An X-ray co-crystal structure of the α-thrombin:PS2-aptamer complex reveals a localized induced-fit rearrangement of the PS2-containing nucleotide which leads to enhanced target interaction. High-level quantum mechanical calculations for model systems that mimic the PS2 moiety and phenylalanine demonstrate that an edge-on interaction between sulfur and the aromatic ring is quite favorable, and also confirm that the sulfur analogs are much more polarizable than the corresponding phosphates. This favorable interaction involving the sulfur atom is likely even more significant in the full aptamer-protein complexes than in the model systems.
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Affiliation(s)
| | - Martin Egli
- Department of Biochemistry, Vanderbilt University, School of Medicine, Nashville, TN 37232, USA
| | - Nehemiah Cox
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Karen Mercier
- Biointeractions Division, Horiba Scientific, Avenue de la Vauve - Passage JobinYvon CS 45002 Palaiseau, France
| | - Jonas Nascimento Conde
- Instituto de Biofísica Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941, Brazil
| | - Pradeep S Pallan
- Department of Biochemistry, Vanderbilt University, School of Medicine, Nashville, TN 37232, USA
| | - Daniella M Mizurini
- Instituto de Bioquimica Médica Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941, Brazil
| | - Malgorzata Sierant
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Lodz, Sienkiewicza 112, Poland
| | - Fatima-Ezzahra Hibti
- Biointeractions Division, Horiba Scientific, Avenue de la Vauve - Passage JobinYvon CS 45002 Palaiseau, France
| | - Tom Hassell
- MilliporeSigma, 9186 Six Pines, The Woodlands, TX 77380, USA
| | - Tianzhi Wang
- The Sealy Center for Structural Biology & Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Feng-Wu Liu
- School of Pharmaceutical Sciences, Zhengzhou University, Science Avenue 100, Zhengzhou 450001, Henan, China
| | - Hong-Min Liu
- School of Pharmaceutical Sciences, Zhengzhou University, Science Avenue 100, Zhengzhou 450001, Henan, China
| | - Carlos Martinez
- MilliporeSigma, 9186 Six Pines, The Woodlands, TX 77380, USA
| | - Anil K Sood
- Departments of Gynecologic Oncology and Cancer Biology, and Center for RNAi and Non-coding RNA, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Terry P Lybrand
- Departments of Chemistry and Pharmacology, and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Chiraz Frydman
- Biointeractions Division, Horiba Scientific, Avenue de la Vauve - Passage JobinYvon CS 45002 Palaiseau, France
| | - Robson Q Monteiro
- Instituto de Bioquimica Médica Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941, Brazil
| | - Richard H Gomer
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Barbara Nawrot
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Lodz, Sienkiewicza 112, Poland
| | - Xianbin Yang
- AM Biotechnologies, LLC, 12521 Gulf Freeway, Houston, TX 77034, USA
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41
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Shishovs M, Rumnieks J, Diebolder C, Jaudzems K, Andreas LB, Stanek J, Kazaks A, Kotelovica S, Akopjana I, Pintacuda G, Koning RI, Tars K. Structure of AP205 Coat Protein Reveals Circular Permutation in ssRNA Bacteriophages. J Mol Biol 2016; 428:4267-4279. [PMID: 27591890 DOI: 10.1016/j.jmb.2016.08.025] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/18/2016] [Accepted: 08/27/2016] [Indexed: 12/18/2022]
Abstract
AP205 is a single-stranded RNA bacteriophage that has a coat protein sequence not similar to any other known single-stranded RNA phage. Here, we report an atomic-resolution model of the AP205 virus-like particle based on a crystal structure of an unassembled coat protein dimer and a cryo-electron microscopy reconstruction of the assembled particle, together with secondary structure information from site-specific solid-state NMR data. The AP205 coat protein dimer adopts the conserved Leviviridae coat protein fold except for the N-terminal region, which forms a beta-hairpin in the other known single-stranded RNA phages. AP205 has a similar structure at the same location formed by N- and C-terminal beta-strands, making it a circular permutant compared to the other coat proteins. The permutation moves the coat protein termini to the most surface-exposed part of the assembled particle, which explains its increased tolerance to long N- and C-terminal fusions.
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Affiliation(s)
- Mihails Shishovs
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067 Riga, Latvia
| | - Janis Rumnieks
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067 Riga, Latvia
| | - Christoph Diebolder
- Netherlands Centre for Electron Nanoscopy, Institute of Biology Leiden, Leiden University Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Kristaps Jaudzems
- Université de Lyon, Centre de RMN à Très Hauts Champs, Institut des Sciences Analytiques (UMR 5280 - CNRS, ENS Lyon, UCB Lyon 1), 69100 Villeurbanne, France
| | - Loren B Andreas
- Université de Lyon, Centre de RMN à Très Hauts Champs, Institut des Sciences Analytiques (UMR 5280 - CNRS, ENS Lyon, UCB Lyon 1), 69100 Villeurbanne, France
| | - Jan Stanek
- Université de Lyon, Centre de RMN à Très Hauts Champs, Institut des Sciences Analytiques (UMR 5280 - CNRS, ENS Lyon, UCB Lyon 1), 69100 Villeurbanne, France
| | - Andris Kazaks
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067 Riga, Latvia
| | - Svetlana Kotelovica
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067 Riga, Latvia
| | - Inara Akopjana
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067 Riga, Latvia
| | - Guido Pintacuda
- Université de Lyon, Centre de RMN à Très Hauts Champs, Institut des Sciences Analytiques (UMR 5280 - CNRS, ENS Lyon, UCB Lyon 1), 69100 Villeurbanne, France
| | - Roman I Koning
- Netherlands Centre for Electron Nanoscopy, Institute of Biology Leiden, Leiden University Einsteinweg 55, 2333 CC Leiden, The Netherlands; Department of Cell Biology, Leiden University Medical Center, Postal Zone S1-P, P.O.Box 9600, 2300 RC Leiden, The Netherlands
| | - Kaspars Tars
- Latvian Biomedical Research and Study Center, Rātsupītes 1, LV1067 Riga, Latvia; Faculty of Biology, Department of Molecular Biology, University of Latvia, Jelgavas 1, LV-1004 Riga, Latvia.
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42
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Koning RI, Gomez-Blanco J, Akopjana I, Vargas J, Kazaks A, Tars K, Carazo JM, Koster AJ. Asymmetric cryo-EM reconstruction of phage MS2 reveals genome structure in situ. Nat Commun 2016; 7:12524. [PMID: 27561669 PMCID: PMC5007439 DOI: 10.1038/ncomms12524] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 07/11/2016] [Indexed: 01/22/2023] Open
Abstract
In single-stranded ribonucleic acid (RNA) viruses, virus capsid assembly and genome packaging are intertwined processes. Using cryo-electron microscopy and single particle analysis we determined the asymmetric virion structure of bacteriophage MS2, which includes 178 copies of the coat protein, a single copy of the A-protein and the RNA genome. This reveals that in situ, the viral RNA genome can adopt a defined conformation. The RNA forms a branched network of stem-loops that almost all allocate near the capsid inner surface, while predominantly binding to coat protein dimers that are located in one-half of the capsid. This suggests that genomic RNA is highly involved in genome packaging and virion assembly. MS2 is a single-stranded RNA bacteriophage that infects its host via adsorption to bacterial pili. Here the authors visualize the MS2 virion with asymmetric cryo-EM reconstruction, revealing that the genome of MS2 adopts a specific structure of asymmetrically distributed stem-loops connected to the capsid.
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Affiliation(s)
- Roman I Koning
- Department of Molecular Cell Biology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands.,Netherlands Centre for Electron Nanoscopy, Institute of Biology Leiden, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Josue Gomez-Blanco
- Biocomputing Unit, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Darwin 3, Campus Universidad Autónoma, Cantoblanco, Madrid 28049, Spain
| | - Inara Akopjana
- Biomedical Research and Study Centre, Ratsupites 1, LV-1067 Riga, Latvia
| | - Javier Vargas
- Biocomputing Unit, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Darwin 3, Campus Universidad Autónoma, Cantoblanco, Madrid 28049, Spain
| | - Andris Kazaks
- Biomedical Research and Study Centre, Ratsupites 1, LV-1067 Riga, Latvia
| | - Kaspars Tars
- Biomedical Research and Study Centre, Ratsupites 1, LV-1067 Riga, Latvia
| | - José María Carazo
- Biocomputing Unit, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Darwin 3, Campus Universidad Autónoma, Cantoblanco, Madrid 28049, Spain
| | - Abraham J Koster
- Department of Molecular Cell Biology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands.,Netherlands Centre for Electron Nanoscopy, Institute of Biology Leiden, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
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43
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Abstract
Interactions between protein and RNA play a key role in many biological processes in the gene expression pathway. Those interactions are mediated through a variety of RNA-binding protein domains, among them the highly abundant RNA recognition motif (RRM). Here we studied protein-RNA complexes from different RNA binding domain families solved by NMR and x-ray crystallography. Characterizing the structural properties of the RNA at the binding interfaces revealed an unexpected number of nucleotides with unusual RNA conformations, specifically found in RNA-RRM complexes. Moreover, we observed that the RNA nucleotides that are directly involved in interactions with the RRM domains, via hydrogen bonds and hydrophobic contacts, are significantly enriched with unique RNA conformations. Further examination of the sequences binding the RRM domain showed a preference for G nucleotides in syn conformation to precede or to follow U nucleotides in the anti-conformation, and U nucleotides in C2' endo conformation to precede U and G nucleotides possessing the more common C3' endo conformation. These findings imply a possible mode of RNA recognition by the RRM domains which enables the recognition of a wide variety of different RNA sequences and shapes. Overall, this study suggests an additional way by which the RRM domain recognizes its RNA target, involving a conformational readout.
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Affiliation(s)
- Efrat Kligun
- a Department of Biology; Technion - Israel Institute of Technology ; Haifa , Israel
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44
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Rolfsson Ó, Middleton S, Manfield IW, White SJ, Fan B, Vaughan R, Ranson NA, Dykeman E, Twarock R, Ford J, Kao CC, Stockley PG. Direct Evidence for Packaging Signal-Mediated Assembly of Bacteriophage MS2. J Mol Biol 2016; 428:431-48. [PMID: 26608810 PMCID: PMC4751978 DOI: 10.1016/j.jmb.2015.11.014] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 11/06/2015] [Accepted: 11/08/2015] [Indexed: 01/20/2023]
Abstract
Using cross-linking coupled to matrix-assisted laser desorption/ionization mass spectrometry and CLIP-Seq sequencing, we determined the peptide and oligonucleotide sequences at the interfaces between the capsid proteins and the genomic RNA of bacteriophage MS2. The results suggest that the same coat protein (CP)-RNA and maturation protein (MP)-RNA interfaces are used in every viral particle. The portions of the viral RNA in contact with CP subunits span the genome, consistent with a large number of discrete and similar contacts within each particle. Many of these sites match previous predictions of the locations of multiple, dispersed and degenerate RNA sites with cognate CP affinity termed packaging signals (PSs). Chemical RNA footprinting was used to compare the secondary structures of protein-free genomic fragments and the RNA in the virion. Some PSs are partially present in protein-free RNA but others would need to refold from their dominant solution conformations to form the contacts identified in the virion. The RNA-binding peptides within the MP map to two sections of the N-terminal half of the protein. Comparison of MP sequences from related phages suggests a similar arrangement of RNA-binding sites, although these N-terminal regions have only limited sequence conservation. In contrast, the sequences of the C-termini are highly conserved, consistent with them encompassing pilin-binding domains required for initial contact with host cells. These results provide independent and unambiguous support for the assembly of MS2 virions via a PS-mediated mechanism involving a series of induced-fit viral protein interactions with RNA.
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Affiliation(s)
- Óttar Rolfsson
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Stefani Middleton
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA; The Center for Genomics and Bioinformatics, Indiana University, Bloomington, IN 47405, USA
| | - Iain W Manfield
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Simon J White
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Baochang Fan
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Robert Vaughan
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Neil A Ranson
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Eric Dykeman
- Department of Biology and Mathematics and York Centre for Complex Systems Analysis, University of York, York YO10 5DD, United Kingdom
| | - Reidun Twarock
- Department of Biology and Mathematics and York Centre for Complex Systems Analysis, University of York, York YO10 5DD, United Kingdom
| | - James Ford
- The Center for Genomics and Bioinformatics, Indiana University, Bloomington, IN 47405, USA
| | - C Cheng Kao
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Peter G Stockley
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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45
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Stockley PG, White SJ, Dykeman E, Manfield I, Rolfsson O, Patel N, Bingham R, Barker A, Wroblewski E, Chandler-Bostock R, Weiß EU, Ranson NA, Tuma R, Twarock R. Bacteriophage MS2 genomic RNA encodes an assembly instruction manual for its capsid. BACTERIOPHAGE 2016; 6:e1157666. [PMID: 27144089 PMCID: PMC4836477 DOI: 10.1080/21597081.2016.1157666] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 02/15/2016] [Accepted: 02/17/2016] [Indexed: 12/11/2022]
Abstract
Using RNA-coat protein crosslinking we have shown that the principal RNA recognition surface on the interior of infectious MS2 virions overlaps with the known peptides that bind the high affinity translational operator, TR, within the phage genome. The data also reveal the sequences of genomic fragments in contact with the coat protein shell. These show remarkable overlap with previous predictions based on the hypothesis that virion assembly is mediated by multiple sequences-specific contacts at RNA sites termed Packaging Signals (PSs). These PSs are variations on the TR stem-loop sequence and secondary structure. They act co-operatively to regulate the dominant assembly pathway and ensure cognate RNA encapsidation. In MS2, they also trigger conformational change in the dimeric capsomere creating the A/B quasi-conformer, 60 of which are needed to complete the T=3 capsid. This is the most compelling demonstration to date that this ssRNA virus, and by implications potentially very many of them, assemble via a PS-mediated assembly mechanism.
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Affiliation(s)
- Peter G. Stockley
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Simon J. White
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Eric Dykeman
- Department of Biology and Mathematics & York Center for Complex Systems Analysis, University of York, York, UK
| | - Iain Manfield
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Ottar Rolfsson
- Center for Systems Biology, University of Iceland, University of Iceland Biomedical Center, Reykjavik, Iceland
| | - Nikesh Patel
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Richard Bingham
- Department of Biology and Mathematics & York Center for Complex Systems Analysis, University of York, York, UK
| | - Amy Barker
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Emma Wroblewski
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | | | - Eva U. Weiß
- Department of Biology and Mathematics & York Center for Complex Systems Analysis, University of York, York, UK
| | - Neil A. Ranson
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Roman Tuma
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Reidun Twarock
- Department of Biology and Mathematics & York Center for Complex Systems Analysis, University of York, York, UK
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46
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Tethered Function Assays as Tools to Elucidate the Molecular Roles of RNA-Binding Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 907:61-88. [PMID: 27256382 DOI: 10.1007/978-3-319-29073-7_3] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Dynamic regulation of RNA molecules is critical to the survival and development of cells. Messenger RNAs are transcribed in the nucleus as intron-containing pre-mRNAs and bound by RNA-binding proteins, which control their fate by regulating RNA stability, splicing, polyadenylation, translation, and cellular localization. Most RBPs have distinct mRNA-binding and functional domains; thus, the function of an RBP can be studied independently of RNA-binding by artificially recruiting the RBP to a reporter RNA and then measuring the effect of RBP recruitment on reporter splicing, stability, translational efficiency, or intracellular trafficking. These tethered function assays therefore do not require prior knowledge of the RBP's endogenous RNA targets or its binding sites within these RNAs. Here, we provide an overview of the experimental strategy and the strengths and limitations of common tethering systems. We illustrate specific examples of the application of the assay in elucidating the function of various classes of RBPs. We also discuss how classic tethering assay approaches and insights gained from them have been empowered by more recent technological advances, including efficient genome editing and high-throughput RNA-sequencing.
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47
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A novel method to produce armored double-stranded DNA by encapsulation of MS2 viral capsids. Appl Microbiol Biotechnol 2015; 99:7047-57. [PMID: 25981999 PMCID: PMC7079959 DOI: 10.1007/s00253-015-6664-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 04/21/2015] [Accepted: 05/01/2015] [Indexed: 02/08/2023]
Abstract
With the rapid development of molecular diagnostic techniques, there is a growing need for quality controls and standards with favorable properties to monitor the entire detection process. In this study, we describe a novel method to produce armored hepatitis B virus (HBV) and human papillomavirus (HPV) DNA for use in nucleic acid tests, which was confirmed to be stable, homogeneous, noninfectious, nuclease resistant, and safe for shipping. We demonstrated that MS2 bacteriophage could successfully package double-stranded DNA of 1.3-, 3-, 3.5-, and 6.5-kb length into viral capsids with high reassembly efficiency. This is the first application of RNA bacteriophage MS2 as a platform to encapsulate double-stranded DNA, forming virus-like particles (VLPs) which were indistinguishable from native MS2 capsids in size and morphology. Moreover, by analyzing the interaction mechanism of pac site and the MS2 coat protein (CP), we found that in addition to the recognized initiation signal TR-RNA, TR-DNA can also trigger spontaneous reassembly of CP dimers, providing a more convenient and feasible method of assembly. In conclusion, this straightforward and reliable manufacturing approach makes armored DNA an ideal control and standard for use in clinical laboratory tests and diagnostics, possessing prospects for broad application, especially providing a new platform for the production of quality controls for DNA viruses.
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48
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Garmann RF, Gopal A, Athavale SS, Knobler CM, Gelbart WM, Harvey SC. Visualizing the global secondary structure of a viral RNA genome with cryo-electron microscopy. RNA (NEW YORK, N.Y.) 2015; 21:877-886. [PMID: 25752599 PMCID: PMC4408795 DOI: 10.1261/rna.047506.114] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 12/30/2014] [Indexed: 05/29/2023]
Abstract
The lifecycle, and therefore the virulence, of single-stranded (ss)-RNA viruses is regulated not only by their particular protein gene products, but also by the secondary and tertiary structure of their genomes. The secondary structure of the entire genomic RNA of satellite tobacco mosaic virus (STMV) was recently determined by selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE). The SHAPE analysis suggested a single highly extended secondary structure with much less branching than occurs in the ensemble of structures predicted by purely thermodynamic algorithms. Here we examine the solution-equilibrated STMV genome by direct visualization with cryo-electron microscopy (cryo-EM), using an RNA of similar length transcribed from the yeast genome as a control. The cryo-EM data reveal an ensemble of branching patterns that are collectively consistent with the SHAPE-derived secondary structure model. Thus, our results both elucidate the statistical nature of the secondary structure of large ss-RNAs and give visual support for modern RNA structure determination methods. Additionally, this work introduces cryo-EM as a means to distinguish between competing secondary structure models if the models differ significantly in terms of the number and/or length of branches. Furthermore, with the latest advances in cryo-EM technology, we suggest the possibility of developing methods that incorporate restraints from cryo-EM into the next generation of algorithms for the determination of RNA secondary and tertiary structures.
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Affiliation(s)
- Rees F Garmann
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Ajaykumar Gopal
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Shreyas S Athavale
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332, USA School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Charles M Knobler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - William M Gelbart
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Stephen C Harvey
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332, USA School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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49
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Abstract
I present a review of the theoretical and computational methodologies that have been used to model the assembly of viral capsids. I discuss the capabilities and limitations of approaches ranging from equilibrium continuum theories to molecular dynamics simulations, and I give an overview of some of the important conclusions about virus assembly that have resulted from these modeling efforts. Topics include the assembly of empty viral shells, assembly around single-stranded nucleic acids to form viral particles, and assembly around synthetic polymers or charged nanoparticles for nanotechnology or biomedical applications. I present some examples in which modeling efforts have promoted experimental breakthroughs, as well as directions in which the connection between modeling and experiment can be strengthened.
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50
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Abstract
We present direct experimental evidence that assembly of a single-stranded RNA virus occurs via a packaging signal-mediated mechanism. We show that the sequences of coat protein recognition motifs within multiple, dispersed, putative RNA packaging signals, as well as their relative spacing within a genomic fragment, act collectively to influence the fidelity and yield of capsid self-assembly in vitro. These experiments confirm that the selective advantages for viral yield and encapsidation specificity, predicted from previous modeling of packaging signal-mediated assembly, are found in Nature. Regions of the genome that act as packaging signals also function in translational and transcriptional enhancement, as well as directly coding for the coat protein, highlighting the density of encoded functions within the viral RNA. Assembly and gene expression are therefore direct molecular competitors for different functional folds of the same RNA sequence. The strongest packaging signal in the test fragment, encodes a region of the coat protein that undergoes a conformational change upon contact with packaging signals. A similar phenomenon occurs in other RNA viruses for which packaging signals are known. These contacts hint at an even deeper density of encoded functions in viral RNA, which if confirmed, would have profound consequences for the evolution of this class of pathogens.
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