101
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Identification of the RNA Pseudoknot within the 3' End of the Porcine Reproductive and Respiratory Syndrome Virus Genome as a Pathogen-Associated Molecular Pattern To Activate Antiviral Signaling via RIG-I and Toll-Like Receptor 3. J Virol 2018; 92:JVI.00097-18. [PMID: 29618647 DOI: 10.1128/jvi.00097-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 03/28/2018] [Indexed: 12/24/2022] Open
Abstract
Once infected by viruses, cells can detect pathogen-associated molecular patterns (PAMPs) on viral nucleic acid by host pattern recognition receptors (PRRs) to initiate the antiviral response. Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of porcine reproductive and respiratory syndrome (PRRS), characterized by reproductive failure in sows and respiratory diseases in pigs of different ages. To date, the sensing mechanism of PRRSV has not been elucidated. Here, we reported that the pseudoknot region residing in the 3' untranslated regions (UTR) of the PRRSV genome, which has been proposed to regulate RNA synthesis and virus replication, was sensed as nonself by retinoic acid-inducible gene I (RIG-I) and Toll-like receptor 3 (TLR3) and strongly induced type I interferons (IFNs) and interferon-stimulated genes (ISGs) in porcine alveolar macrophages (PAMs). The interaction between the two stem-loops inside the pseudoknot structure was sufficient for IFN induction, since disruption of the pseudoknot interaction powerfully dampened the IFN induction. Furthermore, transfection of the 3' UTR pseudoknot transcripts in PAMs inhibited PRRSV replication in vitro Importantly, the predicted similar structures of other arterivirus members, including equine arteritis virus (EAV), lactate dehydrogenase-elevating virus (LDV), and simian hemorrhagic fever virus (SHFV), also displayed strong IFN induction activities. Together, in this work we identified an innate recognition mechanism by which the PRRSV 3' UTR pseudoknot region served as PAMPs of arteriviruses and activated innate immune signaling to produce IFNs that inhibit virus replication. All of these results provide novel insights into innate immune recognition during virus infection.IMPORTANCE PRRS is the most common viral disease in the pork industry. It is caused by PRRSV, a positive single-stranded RNA virus, whose infection often leads to persistent infection. To date, it is not yet clear how PRRSV is recognized by the host and what is the exact mechanism of IFN induction. Here, we investigated the nature of PAMPs on PRRSV and the associated PRRs. We found that the 3' UTR pseudoknot region of PRRSV, which has been proposed to regulate viral RNA synthesis, could act as PAMPs recognized by RIG-I and TLR3 to induce type I IFN production to suppress PRRSV infection. This report is the first detailed description of pattern recognition for PRRSV, which is important in understanding the antiviral response of arteriviruses, especially PRRSV, and extends our knowledge on virus recognition.
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102
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Baronti L, Karlsson H, Marušič M, Petzold K. A guide to large-scale RNA sample preparation. Anal Bioanal Chem 2018; 410:3239-3252. [PMID: 29546546 PMCID: PMC5937877 DOI: 10.1007/s00216-018-0943-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/25/2018] [Accepted: 02/05/2018] [Indexed: 12/30/2022]
Abstract
RNA is becoming more important as an increasing number of functions, both regulatory and enzymatic, are being discovered on a daily basis. As the RNA boom has just begun, most techniques are still in development and changes occur frequently. To understand RNA functions, revealing the structure of RNA is of utmost importance, which requires sample preparation. We review the latest methods to produce and purify a variation of RNA molecules for different purposes with the main focus on structural biology and biophysics. We present a guide aimed at identifying the most suitable method for your RNA and your biological question and highlighting the advantages of different methods. Graphical abstract In this review we present different methods for large-scale production and purification of RNAs for structural and biophysical studies.
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Affiliation(s)
- Lorenzo Baronti
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles Väg 2, 17177, Stockholm, Sweden
| | - Hampus Karlsson
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles Väg 2, 17177, Stockholm, Sweden
| | - Maja Marušič
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles Väg 2, 17177, Stockholm, Sweden
| | - Katja Petzold
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles Väg 2, 17177, Stockholm, Sweden.
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103
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Liu Y, Holmstrom E, Yu P, Tan K, Zuo X, Nesbitt DJ, Sousa R, Stagno JR, Wang YX. Incorporation of isotopic, fluorescent, and heavy-atom-modified nucleotides into RNAs by position-selective labeling of RNA. Nat Protoc 2018; 13:987-1005. [PMID: 29651055 DOI: 10.1038/nprot.2018.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Site-specific incorporation of labeled nucleotides is an extremely useful synthetic tool for many structural studies (e.g., NMR, electron paramagnetic resonance (EPR), fluorescence resonance energy transfer (FRET), and X-ray crystallography) of RNA. However, specific-position-labeled RNAs >60 nt are not commercially available on a milligram scale. Position-selective labeling of RNA (PLOR) has been applied to prepare large RNAs labeled at desired positions, and all the required reagents are commercially available. Here, we present a step-by-step protocol for the solid-liquid hybrid phase method PLOR to synthesize 71-nt RNA samples with three different modification applications, containing (i) a 13C15N-labeled segment; (ii) discrete residues modified with Cy3, Cy5, or biotin; or (iii) two iodo-U residues. The flexible procedure enables a wide range of downstream biophysical analyses using precisely localized functionalized nucleotides. All three RNAs were obtained in <2 d, excluding time for preparing reagents and optimizing experimental conditions. With optimization, the protocol can be applied to other RNAs with various labeling schemes, such as ligation of segmentally labeled fragments.
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Affiliation(s)
- Yu Liu
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.,Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Erik Holmstrom
- JILA, National Institute of Standards and Technology and Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado, USA
| | - Ping Yu
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Kemin Tan
- Structural Biology Center, Department of Biosciences, Argonne National Laboratory, Argonne, Illinois, USA
| | - Xiaobing Zuo
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, USA
| | - David J Nesbitt
- JILA, National Institute of Standards and Technology and Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado, USA
| | - Rui Sousa
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Jason R Stagno
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Yun-Xing Wang
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
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104
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Zhang K, Keane SC, Su Z, Irobalieva RN, Chen M, Van V, Sciandra CA, Marchant J, Heng X, Schmid MF, Case DA, Ludtke SJ, Summers MF, Chiu W. Structure of the 30 kDa HIV-1 RNA Dimerization Signal by a Hybrid Cryo-EM, NMR, and Molecular Dynamics Approach. Structure 2018; 26:490-498.e3. [PMID: 29398526 PMCID: PMC5842133 DOI: 10.1016/j.str.2018.01.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 11/12/2017] [Accepted: 01/03/2018] [Indexed: 02/01/2023]
Abstract
Cryoelectron microscopy (cryo-EM) and nuclear magnetic resonance (NMR) spectroscopy are routinely used to determine structures of macromolecules with molecular weights over 65 and under 25 kDa, respectively. We combined these techniques to study a 30 kDa HIV-1 dimer initiation site RNA ([DIS]2; 47 nt/strand). A 9 Å cryo-EM map clearly shows major groove features of the double helix and a right-handed superhelical twist. Simulated cryo-EM maps generated from time-averaged molecular dynamics trajectories (10 ns) exhibited levels of detail similar to those in the experimental maps, suggesting internal structural flexibility limits the cryo-EM resolution. Simultaneous inclusion of the cryo-EM map and 2H-edited NMR-derived distance restraints during structure refinement generates a structure consistent with both datasets and supporting a flipped-out base within a conserved purine-rich bulge. Our findings demonstrate the power of combining global and local structural information from these techniques for structure determination of modest-sized RNAs.
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Affiliation(s)
- Kaiming Zhang
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sarah C Keane
- Howard Hughes Medical Institute (HHMI) and Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, MD 21250, USA
| | - Zhaoming Su
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Rossitza N Irobalieva
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Muyuan Chen
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Verna Van
- Howard Hughes Medical Institute (HHMI) and Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, MD 21250, USA
| | - Carly A Sciandra
- Howard Hughes Medical Institute (HHMI) and Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, MD 21250, USA
| | - Jan Marchant
- Howard Hughes Medical Institute (HHMI) and Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, MD 21250, USA
| | - Xiao Heng
- Department of Biochemistry, University of Missouri-Columbia, Columbia, MO 65211, USA
| | - Michael F Schmid
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - David A Case
- Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA.
| | - Steven J Ludtke
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Michael F Summers
- Howard Hughes Medical Institute (HHMI) and Department of Chemistry and Biochemistry, University of Maryland Baltimore County (UMBC), Baltimore, MD 21250, USA.
| | - Wah Chiu
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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105
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Zhang W, Tam CP, Zhou L, Oh SS, Wang J, Szostak JW. Structural Rationale for the Enhanced Catalysis of Nonenzymatic RNA Primer Extension by a Downstream Oligonucleotide. J Am Chem Soc 2018; 140:2829-2840. [PMID: 29411978 PMCID: PMC6326529 DOI: 10.1021/jacs.7b11750] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Indexed: 01/28/2023]
Abstract
Nonenzymatic RNA primer extension by activated mononucleotides has long served as a model for the study of prebiotic RNA copying. We have recently shown that the rate of primer extension is greatly enhanced by the formation of an imidazolium-bridged dinucleotide between the incoming monomer and a second, downstream activated monomer. However, the rate of primer extension is further enhanced if the downstream monomer is replaced by an activated oligonucleotide. Even an unactivated downstream oligonucleotide provides a modest enhancement in the rate of reaction of a primer with a single activated monomer. Here we study the mechanism of these effects through crystallographic studies of RNA complexes with the recently synthesized nonhydrolyzable substrate analog, guanosine 5'-(4-methylimidazolyl)-phosphonate (ICG). ICG mimics 2-methylimidazole activated guanosine-5'-phosphate (2-MeImpG), a commonly used substrate in nonenzymatic primer extension experiments. We present crystal structures of primer-template complexes with either one or two ICG residues bound downstream of a primer. In both cases, the aryl-phosphonate moiety of the ICG adjacent to the primer is disordered. To investigate the effect of a downstream oligonucleotide, we transcribed a short RNA oligonucleotide with either a 5'-ICG residue, a 5'-phosphate or a 5'-hydroxyl. We then determined crystal structures of primer-template complexes with a bound ICG monomer sandwiched between the primer and each of the three downstream oligonucleotides. Surprisingly, all three oligonucleotides rigidify the ICG monomer conformation and position it for attack by the primer 3'-hydroxyl. Furthermore, when GpppG, an analog of the imidazolium-bridged intermediate, is sandwiched between an upstream primer and a downstream helper oligonucleotide, or covalently linked to the 5'-end of the downstream oligonucleotide, the complex is better preorganized for primer extension than in the absence of a downstream oligonucleotide. Our results suggest that a downstream helper oligonucleotide contributes to the catalysis of primer extension by favoring a reactive conformation of the primer-template-intermediate complex.
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Affiliation(s)
- Wen Zhang
- Howard
Hughes Medical Institute and Center for Computational and Integrative
Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Department
of Genetics, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Chun Pong Tam
- Howard
Hughes Medical Institute and Center for Computational and Integrative
Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Lijun Zhou
- Howard
Hughes Medical Institute and Center for Computational and Integrative
Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Department
of Genetics, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Seung Soo Oh
- Howard
Hughes Medical Institute and Center for Computational and Integrative
Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Department
of Genetics, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Jiawei Wang
- School
of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jack W. Szostak
- Howard
Hughes Medical Institute and Center for Computational and Integrative
Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Department
of Genetics, Harvard Medical School, Boston, Massachusetts 02114, United States
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
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106
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Yang Y, Wang S. RNA Characterization by Solid-State NMR Spectroscopy. Chemistry 2018; 24:8698-8707. [DOI: 10.1002/chem.201705583] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Indexed: 02/05/2023]
Affiliation(s)
- Yufei Yang
- College of Chemistry and Molecular Engineering and Beijing NMR Center; Peking University; No.5 Yiheyuan Road, Haidian District Beijing 100871 P. R. China
| | - Shenlin Wang
- College of Chemistry and Molecular Engineering and Beijing NMR Center; Peking University; No.5 Yiheyuan Road, Haidian District Beijing 100871 P. R. China
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107
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Watters KE, Lucks JB. Mapping RNA Structure In Vitro with SHAPE Chemistry and Next-Generation Sequencing (SHAPE-Seq). Methods Mol Biol 2018; 1490:135-62. [PMID: 27665597 DOI: 10.1007/978-1-4939-6433-8_9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mapping RNA structure with selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) chemistry has proven to be a versatile method for characterizing RNA structure in a variety of contexts. SHAPE reagents covalently modify RNAs in a structure-dependent manner to create adducts at the 2'-OH group of the ribose backbone at nucleotides that are structurally flexible. The positions of these adducts are detected using reverse transcriptase (RT) primer extension, which stops one nucleotide before the modification, to create a pool of cDNAs whose lengths reflect the location of SHAPE modification. Quantification of the cDNA pools is used to estimate the "reactivity" of each nucleotide in an RNA molecule to the SHAPE reagent. High reactivities indicate nucleotides that are structurally flexible, while low reactivities indicate nucleotides that are inflexible. These SHAPE reactivities can then be used to infer RNA structures by restraining RNA structure prediction algorithms. Here, we provide a state-of-the-art protocol describing how to perform in vitro RNA structure probing with SHAPE chemistry using next-generation sequencing to quantify cDNA pools and estimate reactivities (SHAPE-Seq). The use of next-generation sequencing allows for higher throughput, more consistent data analysis, and multiplexing capabilities. The technique described herein, SHAPE-Seq v2.0, uses a universal reverse transcription priming site that is ligated to the RNA after SHAPE modification. The introduced priming site allows for the structural analysis of an RNA independent of its sequence.
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Affiliation(s)
- Kyle E Watters
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, 14850, USA
| | - Julius B Lucks
- Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, 14850, USA.
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108
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Liao SE, Fukunaga R. Kinetic Analysis of Small Silencing RNA Production by Human and Drosophila Dicer Enzymes In Vitro. Methods Mol Biol 2018; 1680:101-121. [PMID: 29030844 DOI: 10.1007/978-1-4939-7339-2_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Dicer enzymes produce small silencing RNAs such as microRNAs (miRNAs) and small interfering RNAs (siRNAs), which then are loaded into Argonaute proteins and act as sequence-specific guides. A powerful tool to understand the molecular mechanism of small silencing RNA production by Dicers is an in vitro RNA processing assay using recombinant Dicer proteins. Such biochemical analyses have elucidated the substrate specificities and kinetics of Dicers, the mechanism by which the length of small RNAs produced by Dicers is determined, and the effects of Dicer-partner proteins and endogenous small molecules such as ATP and inorganic phosphate on small RNA production by Dicers, among others. Here, we describe methods for in vitro small RNA production assay using recombinant human and Drosophila Dicer proteins.
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Affiliation(s)
- Susan E Liao
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 North Wolfe Street, 521A Physiology Building, Baltimore, MD, 21205, USA
| | - Ryuya Fukunaga
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, 725 North Wolfe Street, 521A Physiology Building, Baltimore, MD, 21205, USA.
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109
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Abstract
This chapter describes a simple and straightforward way to obtain single-stranded circular RNA sequences in vitro. Linear RNA that is phosphorylated at the 5' end is first prepared by a chemical or enzymatic method, then circularized using ligase. The function of the prepared circular RNA molecule, such as an ability to induce translation, can then be investigated.
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Affiliation(s)
- Naoko Abe
- Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Ayumi Kodama
- Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Hiroshi Abe
- Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Japan.
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110
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Specific Chemical Approaches for Studying Mammalian Ribosomes Complexed with Ligands Involved in Selenoprotein Synthesis. Methods Mol Biol 2017. [PMID: 28917038 DOI: 10.1007/978-1-4939-7258-6_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Chemical approaches are very powerful tools for investigating the molecular structure and architecture of large ribonucleoprotein complexes involving ribosomes and other components of the translation system. Application of RNA nucleotide-specific and cross-linking reagents of a broad specificity range allows the researcher to obtain information on the sites of ligand binding to the ribosome and to each other as well as on the RNA rearrangements caused by the binding. Here, we describe specific chemical approaches including chemical probing and site-directed or bifunctional reagent-mediated cross-linking, which have been used for exploring the mechanism of selenocysteine insertion into a polypeptide chain by mammalian ribosomes.
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111
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Shi W, Gong P. A practical approach to generate suitable de novo synthesis RNA template for a flavivirus RNA-dependent RNA polymerase. Virol Sin 2017. [PMID: 28646484 DOI: 10.1007/s12250-017-4003-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Wei Shi
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Peng Gong
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
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112
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Applications of NMR to structure determination of RNAs large and small. Arch Biochem Biophys 2017; 628:42-56. [PMID: 28600200 DOI: 10.1016/j.abb.2017.06.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 05/31/2017] [Accepted: 06/04/2017] [Indexed: 02/07/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool to investigate the structure and dynamics of RNA, because many biologically important RNAs have conformationally flexible structures, which makes them difficult to crystallize. Functional, independently folded RNA domains, range in size between simple stem-loops of as few as 10-20 nucleotides, to 50-70 nucleotides, the size of tRNA and many small ribozymes, to a few hundred nucleotides, the size of more complex RNA enzymes and of the functional domains of non-coding transcripts. In this review, we discuss new methods for sample preparation, assignment strategies and structure determination for independently folded RNA domains of up to 100 kDa in molecular weight.
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113
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Said N, Krupp F, Anedchenko E, Santos KF, Dybkov O, Huang YH, Lee CT, Loll B, Behrmann E, Bürger J, Mielke T, Loerke J, Urlaub H, Spahn CMT, Weber G, Wahl MC. Structural basis for λN-dependent processive transcription antitermination. Nat Microbiol 2017; 2:17062. [DOI: 10.1038/nmicrobiol.2017.62] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/24/2017] [Indexed: 11/09/2022]
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114
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Eggert F, Kulikov K, Domnick C, Leifels P, Kath-Schorr S. Iluminated by foreign letters - Strategies for site-specific cyclopropene modification of large functional RNAs via in vitro transcription. Methods 2017; 120:17-27. [PMID: 28454775 DOI: 10.1016/j.ymeth.2017.04.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 04/18/2017] [Accepted: 04/23/2017] [Indexed: 10/19/2022] Open
Abstract
The synthesis of sequence-specifically modified long RNA molecules, which cannot entirely be prepared via solid phase synthesis methods is experimentally challenging. We are using a new approach based on an expanded genetic alphabet preparing site-specifically modified RNA molecules via standard in vitro transcription. In this report, the site-specific labeling of functional RNAs, in particular ribozymes and a long non-coding RNA with cyclopropene moieties, is presented. We provide detailed instructions for RNA labeling via in vitro transcription and include required analytical methods to verify production and identity of the transcript. We further present post-transcriptional inverse electron demand Diels-Alder cycloaddition reactions on the cyclopropene-modified sequences and discuss applications of the genetic alphabet expansion transcription for in vitro preparation of labeled functional RNAs with complex foldings. In detail, the glmS and CPEB3 ribozymes were site-specifically decorated with methyl cyclopropene moieties using the unnatural TPT3CP triphosphate and were proven to be still functional. In addition, the structurally complex A region of the Xist lncRNA (401nt) was site-specifically modified with methyl cyclopropene and detected by fluorescence after cycloaddition reaction with a tetrazine-BODIPY conjugate.
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Affiliation(s)
- Frank Eggert
- LIMES Institute, Chemical Biology & Medicinal Chemistry Unit, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Katharina Kulikov
- LIMES Institute, Chemical Biology & Medicinal Chemistry Unit, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Christof Domnick
- LIMES Institute, Chemical Biology & Medicinal Chemistry Unit, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Philipp Leifels
- LIMES Institute, Chemical Biology & Medicinal Chemistry Unit, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Stephanie Kath-Schorr
- LIMES Institute, Chemical Biology & Medicinal Chemistry Unit, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany.
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115
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Cantara WA, Olson ED, Musier-Forsyth K. Analysis of RNA structure using small-angle X-ray scattering. Methods 2017; 113:46-55. [PMID: 27777026 PMCID: PMC5253320 DOI: 10.1016/j.ymeth.2016.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 10/10/2016] [Accepted: 10/20/2016] [Indexed: 11/22/2022] Open
Abstract
In addition to their role in correctly attaching specific amino acids to cognate tRNAs, aminoacyl-tRNA synthetases (aaRS) have been found to possess many alternative functions and often bind to and act on other nucleic acids. In contrast to the well-defined 3D structure of tRNA, the structures of many of the other RNAs recognized by aaRSs have not been solved. Despite advances in the use of X-ray crystallography (XRC), nuclear magnetic resonance (NMR) spectroscopy and cryo-electron microscopy (cryo-EM) for structural characterization of biomolecules, significant challenges to solving RNA structures still exist. Recently, small-angle X-ray scattering (SAXS) has been increasingly employed to characterize the 3D structures of RNAs and RNA-protein complexes. SAXS is capable of providing low-resolution tertiary structure information under physiological conditions and with less intensive sample preparation and data analysis requirements than XRC, NMR and cryo-EM. In this article, we describe best practices involved in the process of RNA and RNA-protein sample preparation, SAXS data collection, data analysis, and structural model building.
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Affiliation(s)
- William A Cantara
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, United States
| | - Erik D Olson
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, United States
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, United States.
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116
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Single-Molecule Analysis of Pre-mRNA Splicing with Colocalization Single-Molecule Spectroscopy (CoSMoS). Methods Mol Biol 2017; 1648:27-37. [PMID: 28766287 DOI: 10.1007/978-1-4939-7204-3_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Recent development of single-molecule techniques to study pre-mRNA splicing has provided insights into the dynamic nature of the spliceosome. Colocalization single-molecule spectroscopy (CoSMoS) allows following spliceosome assembly in real time at single-molecule resolution in the full complexity of cellular extracts. A detailed protocol of CoSMoS has been published previously (Anderson and Hoskins, Methods Mol Biol 1126:217-241, 2014). Here, we provide an update on the technical advances since the first CoSMoS studies including slide surface treatment, data processing, and representation. We describe various labeling strategies to generate RNA reporters with multiple dyes (or other moieties) at specific locations.
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117
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Bourbigot S, Dock-Bregeon AC, Eberling P, Coutant J, Kieffer B, Lebars I. Solution structure of the 5'-terminal hairpin of the 7SK small nuclear RNA. RNA (NEW YORK, N.Y.) 2016; 22:1844-1858. [PMID: 27852926 PMCID: PMC5113205 DOI: 10.1261/rna.056523.116] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 09/10/2016] [Indexed: 05/10/2023]
Abstract
The small nuclear 7SK RNA regulates RNA polymerase II (RNA Pol II) transcription, by sequestering and inhibiting the positive transcription elongation factor b (P-TEFb). P-TEFb is stored in the 7SK ribonucleoprotein (RNP) that contains the three nuclear proteins Hexim1, LaRP7, and MePCE. P-TEFb interacts with the protein Hexim1 and the 7SK RNA. Once P-TEFb is released from the 7SK RNP, it activates transcription by phosphorylating the C-terminal domain of RNA Pol II. P-TEFb also plays a crucial role in the replication of the human immunodeficiency virus HIV-1, through its recruitment by the viral transactivator Tat. Previous work demonstrated that the protein Tat promotes the release of P-TEFb from the 7SK RNP through direct binding to the 7SK RNA. Hexim1 and Tat proteins both comprise conserved and similar arginine-rich motifs that were identified to bind the 7SK RNA at a repeated GAUC site located at the top of the 5'-terminal hairpin (HPI). Here, we report the solution structure of this region as determined by nuclear magnetic resonance, to identify HPI structural features recognized by Hexim1 and Tat. The HPI solution structure displays an elongated shape featuring four helical segments interrupted by one internal loop and three bulges with distinct folds. In particular, the repeated GAUC motif adopts a pre-organized geometry. Our results suggest that the binding of Hexim1 and Tat to the 7SK RNA could originate from a conformational selection of this motif, highlighting how RNA local structure could lead to an adaptive recognition of their partners.
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Affiliation(s)
- Sarah Bourbigot
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR 7104, INSERM U964, Université de Strasbourg, 67404 Illkirch Cedex, France
| | - Anne-Catherine Dock-Bregeon
- Department of Functional Genomics, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), CNRS UMR 8197, INSERM U1024, 75005 Paris, France
| | - Pascal Eberling
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR 7104, INSERM U964, Université de Strasbourg, 67404 Illkirch Cedex, France
| | - Jérôme Coutant
- Bruker BioSpin SAS, BP 10002, 67166 Wissembourg Cedex, France
| | - Bruno Kieffer
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR 7104, INSERM U964, Université de Strasbourg, 67404 Illkirch Cedex, France
| | - Isabelle Lebars
- Department of Integrated Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR 7104, INSERM U964, Université de Strasbourg, 67404 Illkirch Cedex, France
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118
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NMR detection of intermolecular interaction sites in the dimeric 5'-leader of the HIV-1 genome. Proc Natl Acad Sci U S A 2016; 113:13033-13038. [PMID: 27791166 DOI: 10.1073/pnas.1614785113] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
HIV type-1 (HIV-1) contains a pseudodiploid RNA genome that is selected for packaging and maintained in virions as a noncovalently linked dimer. Genome dimerization is mediated by conserved elements within the 5'-leader of the RNA, including a palindromic dimer initiation signal (DIS) that has been proposed to form kissing hairpin and/or extended duplex intermolecular contacts. Here, we have applied a 2H-edited NMR approach to directly probe for intermolecular interactions in the full-length, dimeric HIV-1 5'-leader (688 nucleotides; 230 kDa). The interface is extensive and includes DIS:DIS base pairing in an extended duplex state as well as intermolecular pairing between elements of the upstream Unique-5' (U5) sequence and those near the gag start site (AUG). Other pseudopalindromic regions of the leader, including the transcription activation (TAR), polyadenylation (PolyA), and primer binding (PBS) elements, do not participate in intermolecular base pairing. Using a 2H-edited one-dimensional NMR approach, we also show that the extended interface structure forms on a time scale similar to that of overall RNA dimerization. Our studies indicate that a kissing dimer-mediated structure, if formed, exists only transiently and readily converts to the extended interface structure, even in the absence of the HIV-1 nucleocapsid protein or other RNA chaperones.
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119
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Liu Y, Yu P, Dyba M, Sousa R, Stagno JR, Wang YX. Applications of PLOR in labeling large RNAs at specific sites. Methods 2016; 103:4-10. [PMID: 27033177 PMCID: PMC10802919 DOI: 10.1016/j.ymeth.2016.03.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/15/2016] [Accepted: 03/22/2016] [Indexed: 12/18/2022] Open
Abstract
Incorporation of modified or labeled nucleotides at specific sites in RNAs is critical for gaining insights into the structure and function of RNAs. Preparation of site-specifically labeled large RNAs in amounts suitable for structural or functional studies is extremely difficult using current methodologies. The position-selective labeling of RNA, PLOR, is a recently developed method that makes such syntheses possible. PLOR allows incorporation of various probes, including (2)D/(13)C/(15)N-isotopic labels, Cy3/Cy5/Alexa488/Alexa555 fluorescent dyes, biotin and other chemical groups, into specific positions in long RNAs. Here, we describe in detail the use of PLOR to label RNAs at specific segment(s) or discrete sites.
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Affiliation(s)
- Yu Liu
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
| | - Ping Yu
- Structural Biophysics Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Marzena Dyba
- Structural Biophysics Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Rui Sousa
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Jason R Stagno
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Yun-Xing Wang
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
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120
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Jiménez-Moreno E, Montalvillo-Jiménez L, Santana AG, Gómez AM, Jiménez-Osés G, Corzana F, Bastida A, Jiménez-Barbero J, Cañada FJ, Gómez-Pinto I, González C, Asensio JL. Finding the Right Candidate for the Right Position: A Fast NMR-Assisted Combinatorial Method for Optimizing Nucleic Acids Binders. J Am Chem Soc 2016; 138:6463-74. [DOI: 10.1021/jacs.6b00328] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Ester Jiménez-Moreno
- Instituto de Química Orgánica (IQOG-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
| | | | - Andrés G. Santana
- Instituto de Química Orgánica (IQOG-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
| | - Ana M. Gómez
- Instituto de Química Orgánica (IQOG-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
| | - Gonzalo Jiménez-Osés
- Departamento de Química y Centro de Investigación en
Síntesis Química, Universidad de La Rioja, 26006 Logroño, La Rioja, Spain
- Institute of Biocomputation and Physics of Complex Systems
(BIFI), University of Zaragoza, BIFI-IQFR (CSIC), 50018 Zaragoza, Spain
| | - Francisco Corzana
- Departamento de Química y Centro de Investigación en
Síntesis Química, Universidad de La Rioja, 26006 Logroño, La Rioja, Spain
| | - Agatha Bastida
- Instituto de Química Orgánica (IQOG-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
| | - Jesús Jiménez-Barbero
- Centro de Investigaciones Biológicas (CIB-CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
- Center for Cooperative Research in Biosciences (CIC-bioGUNE), 48160 Derio, Bizkaia, Spain
- Basque Foundation for Science, Ikerbasque, 48013 Bilbao, Bizkaia, Spain
| | | | - Irene Gómez-Pinto
- Instituto de Química-Física Rocasolano (IQFR-CSIC), C/ Serrano 119, 28006 Madrid, Spain
| | - Carlos González
- Instituto de Química-Física Rocasolano (IQFR-CSIC), C/ Serrano 119, 28006 Madrid, Spain
| | - Juan Luis Asensio
- Instituto de Química Orgánica (IQOG-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
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121
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Vasilyev N, Serganov A. Preparation of Short 5'-Triphosphorylated Oligoribonucleotides for Crystallographic and Biochemical Studies. Methods Mol Biol 2016; 1320:11-20. [PMID: 26227034 DOI: 10.1007/978-1-4939-2763-0_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
RNA molecules participate in virtually all cellular processes ranging from transfer of hereditary information to gene expression control. In cells, many RNAs form specific interactions with proteins often using short nucleotide sequences for protein recognition. Biochemical and structural studies of such RNA-protein complexes demand preparation of short RNAs. Although short RNAs can be synthesized chemically, certain proteins require monophosphate or triphosphate moieties on the 5' end of RNA. Given high cost of chemical triphosphorylation, broad application of such RNAs is impractical. In vitro transcription of RNA by DNA-dependent bacteriophage T7 RNA polymerase provides an alternative option to prepare short RNAs with different phosphorylation states as well as modifications on the 5' terminus. Here we outline the in vitro transcription methodology employed to prepare ≤5-mer oligoribonucleotide for structural and biochemical applications. The chapter describes the principles of construct design, in vitro transcription and RNA purification applied for characterization of a protein that targets the 5' end of RNA.
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Affiliation(s)
- Nikita Vasilyev
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, 10016, USA
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122
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Perlíková P, Rylová G, Nauš P, Elbert T, Tloušťová E, Bourderioux A, Slavětínská LP, Motyka K, Doležal D, Znojek P, Nová A, Harvanová M, Džubák P, Šiller M, Hlaváč J, Hajdúch M, Hocek M. 7-(2-Thienyl)-7-Deazaadenosine (AB61), a New Potent Nucleoside Cytostatic with a Complex Mode of Action. Mol Cancer Ther 2016; 15:922-37. [DOI: 10.1158/1535-7163.mct-14-0933] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 01/02/2016] [Indexed: 11/16/2022]
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123
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Rauch BJ, Porter JJ, Mehl RA, Perona JJ. Improved Incorporation of Noncanonical Amino Acids by an Engineered tRNA(Tyr) Suppressor. Biochemistry 2016; 55:618-28. [PMID: 26694948 DOI: 10.1021/acs.biochem.5b01185] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The Methanocaldcoccus jannaschii tyrosyl-tRNA synthetase (TyrRS):tRNA(Tyr) cognate pair has been used to incorporate a large number of noncanonical amino acids (ncAAs) into recombinant proteins in Escherichia coli. However, the structural elements of the suppressor tRNA(Tyr) used in these experiments have not been examined for optimal performance. Here, we evaluate the steady-state kinetic parameters of wild-type M. jannaschii TyrRS and an evolved 3-nitrotyrosyl-tRNA synthetase (nitroTyrRS) toward several engineered tRNA(Tyr) suppressors, and we correlate aminoacylation properties with the efficiency and fidelity of superfolder green fluorescent protein (sfGFP) synthesis in vivo. Optimal ncAA-sfGFP synthesis correlates with improved aminoacylation kinetics for a tRNA(Tyr) amber suppressor with two substitutions in the anticodon loop (G34C/G37A), while four additional mutations in the D and variable loops, present in the tRNA(Tyr) used in all directed evolution experiments to date, are deleterious to function both in vivo and in vitro. These findings extend to three of four other evolved TyrRS enzymes that incorporate distinct ncAAs. Suppressor tRNAs elicit decreases in amino acid Km values for both TyrRS and nitroTyrRS, suggesting that direct anticodon recognition by TyrRS need not be an impediment to superior performance of this orthogonal system and offering insight into novel approaches for directed evolution. The G34C/G37A tRNA(Tyr) may enhance future incorporation of many ncAAs by engineered TyrRS enzymes.
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Affiliation(s)
- Benjamin J Rauch
- Department of Chemistry, Portland State University , P.O. Box 751, Portland, Oregon 97207, United States.,Department of Biochemistry & Molecular Biology, Oregon Health & Sciences University , 3181 Southwest Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Joseph J Porter
- Department of Biochemistry and Biophysics, Oregon State University , 2011 Agriculture and Life Sciences Building, Corvallis, Oregon 97331, United States
| | - Ryan A Mehl
- Department of Biochemistry and Biophysics, Oregon State University , 2011 Agriculture and Life Sciences Building, Corvallis, Oregon 97331, United States
| | - John J Perona
- Department of Chemistry, Portland State University , P.O. Box 751, Portland, Oregon 97207, United States.,Department of Biochemistry & Molecular Biology, Oregon Health & Sciences University , 3181 Southwest Sam Jackson Park Road, Portland, Oregon 97239, United States
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124
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Abstract
Methyl transfer from S-adenosyl methionine (abbreviated as AdoMet) to biologically active molecules such as mRNAs and tRNAs is one of the most fundamental and widespread reactions in nature, occurring in all three domains of life. The measurement of kinetic constants of AdoMet-dependent methyl transfer is therefore important for understanding the reaction mechanism in the context of biology. When kinetic constants of methyl transfer are measured in steady state over multiple rounds of turnover, the meaning of these constants is difficult to define and is often limited by non-chemical steps of the reaction, such as product release after each turnover. Here, the measurement of kinetic constants of methyl transfer by tRNA methyltransferases in rapid equilibrium binding condition for one methyl transfer is described. The advantage of such a measurement is that the meaning of kinetic constants can be directly assigned to the steps associated with the chemistry of methyl transfer, including the substrate binding affinity to the methyltransferase, the pre-chemistry re-arrangement of the active site, and the chemical step of methyl transfer. An additional advantage is that kinetic constants measured for one methyl transfer can be correlated with structural information of the methyltransferase to gain direct insight into its reaction mechanism.
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125
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Ogawa A, Namba Y, Gakumasawa M. Rational optimization of amber suppressor tRNAs toward efficient incorporation of a non-natural amino acid into protein in a eukaryotic wheat germ extract. Org Biomol Chem 2016; 14:2671-8. [DOI: 10.1039/c5ob02533h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Amber suppressor tRNAs (sup-tRNAs) were rationally optimized toward efficient incorporation of a non-natural amino acid (AcPhe) into protein in a eukaryotic wheat germ extract.
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Affiliation(s)
| | - Yuki Namba
- Proteo-Science Center
- Ehime University
- Matsuyama
- Japan
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126
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Rienzo M, Rocchi AR, Threatt SD, Dougherty DA, Lummis SCR. Perturbation of Critical Prolines in Gloeobacter violaceus Ligand-gated Ion Channel (GLIC) Supports Conserved Gating Motions among Cys-loop Receptors. J Biol Chem 2015; 291:6272-80. [PMID: 26668320 PMCID: PMC4813548 DOI: 10.1074/jbc.m115.694372] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Indexed: 11/30/2022] Open
Abstract
Gloeobacter violaceus ligand-gated ion channel (GLIC) has served as a valuable structural and functional model for the eukaryotic Cys-loop receptor superfamily. In Cys-loop and other receptors, we have previously demonstrated the crucial roles played by several conserved prolines. Here we explore the role of prolines in the gating transitions of GLIC. As conventional substitutions at some positions resulted in nonfunctional proteins, we used in vivo non-canonical amino acid mutagenesis to determine the specific structural requirements at these sites. Receptors were expressed heterologously in Xenopus laevis oocytes, and whole-cell electrophysiology was used to monitor channel activity. Pro-119 in the Cys-loop, Pro-198 and Pro-203 in the M1 helix, and Pro-299 in the M4 helix were sensitive to substitution, and distinct roles in receptor activity were revealed for each. In the context of the available structural data for GLIC, the behaviors of Pro-119, Pro-203, and Pro-299 mutants are consistent with earlier proline mutagenesis work. However, the Pro-198 site displays a unique phenotype that gives evidence of the importance of the region surrounding this residue for the correct functioning of GLIC.
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Affiliation(s)
- Matthew Rienzo
- From the Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 and
| | - Angela R Rocchi
- the Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, United Kingdom
| | - Stephanie D Threatt
- From the Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 and
| | - Dennis A Dougherty
- From the Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 and
| | - Sarah C R Lummis
- the Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, United Kingdom
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127
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Abe N, Matsumoto K, Nishihara M, Nakano Y, Shibata A, Maruyama H, Shuto S, Matsuda A, Yoshida M, Ito Y, Abe H. Rolling Circle Translation of Circular RNA in Living Human Cells. Sci Rep 2015; 5:16435. [PMID: 26553571 PMCID: PMC4639774 DOI: 10.1038/srep16435] [Citation(s) in RCA: 287] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 10/12/2015] [Indexed: 01/04/2023] Open
Abstract
We recently reported that circular RNA is efficiently translated by a rolling circle amplification (RCA) mechanism in a cell-free Escherichia coli translation system. Recent studies have shown that circular RNAs composed of exonic sequences are abundant in human cells. However, whether these circular RNAs can be translated into proteins within cells remains unclear. In this study, we prepared circular RNAs with an infinite open reading frame and tested their translation in eukaryotic systems. Circular RNAs were translated into long proteins in rabbit reticulocyte lysate in the absence of any particular element for internal ribosome entry, a poly-A tail, or a cap structure. The translation systems in eukaryote can accept much simpler RNA as a template for protein synthesis by cyclisation. Here, we demonstrated that the circular RNA is efficiently translated in living human cells to produce abundant protein product by RCA mechanism. These findings suggest that translation of exonic circular RNAs present in human cells is more probable than previously thought.
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Affiliation(s)
- Naoko Abe
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.,Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.,Nano Medical Engineering laboratory, RIKEN, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan
| | - Ken Matsumoto
- Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan
| | - Mizuki Nishihara
- Nano Medical Engineering laboratory, RIKEN, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan
| | - Yukiko Nakano
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.,Nano Medical Engineering laboratory, RIKEN, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan
| | - Aya Shibata
- Nano Medical Engineering laboratory, RIKEN, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan
| | - Hideto Maruyama
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.,Nano Medical Engineering laboratory, RIKEN, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan
| | - Satoshi Shuto
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Akira Matsuda
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Minoru Yoshida
- Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan
| | - Yoshihiro Ito
- Nano Medical Engineering laboratory, RIKEN, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan.,Emergent Bioengineering Materials Research Team, RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroshi Abe
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.,Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.,Nano Medical Engineering laboratory, RIKEN, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan.,PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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128
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Ameta S, Becker J, Jäschke A. RNA-peptide conjugate synthesis by inverse-electron demand Diels-Alder reaction. Org Biomol Chem 2015; 12:4701-7. [PMID: 24871687 DOI: 10.1039/c4ob00076e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Here we report an efficient method for the synthesis of RNA-peptide conjugates by inverse-electron demand Diels-Alder reaction. Various dienophiles were enzymatically incorporated into RNA and reacted with a chemically synthesized diene-modified peptide. The Diels-Alder reaction proceeds with near-quantitative yields in aqueous solution with stoichiometric amounts of reactants, even at low micromolar concentrations.
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Affiliation(s)
- Sandeep Ameta
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, Heidelberg 69120, Germany.
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129
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Helmling C, Keyhani S, Sochor F, Fürtig B, Hengesbach M, Schwalbe H. Rapid NMR screening of RNA secondary structure and binding. JOURNAL OF BIOMOLECULAR NMR 2015; 63:67-76. [PMID: 26188386 DOI: 10.1007/s10858-015-9967-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 07/13/2015] [Indexed: 05/10/2023]
Abstract
Determination of RNA secondary structures by NMR spectroscopy is a useful tool e.g. to elucidate RNA folding space or functional aspects of regulatory RNA elements. However, current approaches of RNA synthesis and preparation are usually time-consuming and do not provide analysis with single nucleotide precision when applied for a large number of different RNA sequences. Here, we significantly improve the yield and 3' end homogeneity of RNA preparation by in vitro transcription. Further, by establishing a native purification procedure with increased throughput, we provide a shortcut to study several RNA constructs simultaneously. We show that this approach yields μmol quantities of RNA with purities comparable to PAGE purification, while avoiding denaturation of the RNA.
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Affiliation(s)
- Christina Helmling
- Institut für Organische Chemie und Chemische Biologie, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, 60438, Frankfurt am Main, Germany
| | - Sara Keyhani
- Institut für Organische Chemie und Chemische Biologie, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, 60438, Frankfurt am Main, Germany
| | - Florian Sochor
- Institut für Organische Chemie und Chemische Biologie, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, 60438, Frankfurt am Main, Germany
| | - Boris Fürtig
- Institut für Organische Chemie und Chemische Biologie, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, 60438, Frankfurt am Main, Germany
| | - Martin Hengesbach
- Institut für Organische Chemie und Chemische Biologie, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, 60438, Frankfurt am Main, Germany
| | - Harald Schwalbe
- Institut für Organische Chemie und Chemische Biologie, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, 60438, Frankfurt am Main, Germany.
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130
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Koo SC, Lu J, Li NS, Leung E, Das SR, Harris ME, Piccirilli JA. Transition State Features in the Hepatitis Delta Virus Ribozyme Reaction Revealed by Atomic Perturbations. J Am Chem Soc 2015; 137:8973-82. [PMID: 26125657 PMCID: PMC4758122 DOI: 10.1021/jacs.5b01189] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Endonucleolytic ribozymes constitute a class of non-coding RNAs that catalyze single-strand RNA scission. With crystal structures available for all of the known ribozymes, a major challenge involves relating functional data to the physically observed RNA architecture. In the case of the hepatitis delta virus (HDV) ribozyme, there are three high-resolution crystal structures, the product state of the reaction and two precursor variants, with distinct mechanistic implications. Here, we develop new strategies to probe the structure and catalytic mechanism of a ribozyme. First, we use double-mutant cycles to distinguish differences in functional group proximity implicated by the crystal structures. Second, we use a corrected form of the Brønsted equation to assess the functional significance of general acid catalysis in the system. Our results delineate the functional relevance of atomic interactions inferred from structure, and suggest that the HDV ribozyme transition state resembles the cleavage product in the degree of proton transfer to the leaving group.
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Affiliation(s)
- Selene C. Koo
- Departments of Biochemistry & Molecular Biology, and Chemistry, The University of Chicago, Chicago, IL 60637
| | - Jun Lu
- Departments of Biochemistry & Molecular Biology, and Chemistry, The University of Chicago, Chicago, IL 60637
| | - Nan-Sheng Li
- Departments of Biochemistry & Molecular Biology, and Chemistry, The University of Chicago, Chicago, IL 60637
| | - Edward Leung
- Departments of Biochemistry & Molecular Biology, and Chemistry, The University of Chicago, Chicago, IL 60637
| | - Subha R. Das
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Michael E. Harris
- Department of Biochemistry and Center for Proteomics, Case Western Reserve University School of Medicine, Cleveland, OH 44106
| | - Joseph A. Piccirilli
- Departments of Biochemistry & Molecular Biology, and Chemistry, The University of Chicago, Chicago, IL 60637
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131
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Okui S, Kawai G. In NMR tube transcription for rapid screening of RNA conformation. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2015; 34:103-13. [PMID: 25621704 DOI: 10.1080/15257770.2014.964412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
A simple method for rapid structure screening for RNA by NMR is proposed. Target RNA is transcribed in a NMR tube and its spectra are measured without purification. The proposed method, in NMR tube transcription or INTT, was applied for three RNAs for which NMR spectra have been measured by using the conventionally purified samples. By the real-time measuring, increase of imino proton signals and decrease of NTP signals can be observed. It was confirmed that INTT spectra are in general similar to those obtained by the conventional method. INTT can be used for the first-step screening of RNA folding.
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Affiliation(s)
- Saya Okui
- a Department of Life and Environmental Sciences, Faculty of Engineering , Chiba Institute of Technology , Narashino , Chiba , Japan
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132
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Luo Y, Sintim HO, Dayie TK. Synthesis of a biotinylated photocleavable nucleotide monophosphate for the preparation of natively folded RNAs. Methods Enzymol 2015; 549:115-31. [PMID: 25432747 DOI: 10.1016/b978-0-12-801122-5.00006-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
RNAs are involved in many functional roles in the cell, and this functional diversity is predicated on RNAs adopting requisite three-dimensional architectures. Preparing such "natively folded" RNAs with a homogeneous population is sometimes problematic for structural or enzymatic studies. Yet, standard methods for RNA preparations denature the RNA and create a heterogeneous population of conformers. Therefore, preparation of "natively folded" RNAs without going through the process of denaturing and refolding is important to obtain maximal biological function. Here, we present a simple strategy using "click" chemistry to couple biotin to a "caged" photocleavable (PC) guanosine monophosphate (GMP) in high yield. This biotin-PC-GMP is readily accepted by T7 RNA polymerase to transcribe "natively folded" RNAs ranging in size from 27 to 493 nucleotides. This facile strategy allows efficient biotinylation of RNA and provides a traceless means to remove the biotin after the purification. Such preparation of natively folded RNAs should benefit biophysical and therapeutic applications.
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Affiliation(s)
- Yiling Luo
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, USA
| | - Herman O Sintim
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, USA.
| | - T Kwaku Dayie
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland, USA; Center for Biomolecular Structure and Organization, University of Maryland, College Park, Maryland, USA.
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133
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Trausch JJ, Marcano-Velázquez JG, Matyjasik MM, Batey RT. Metal Ion-Mediated Nucleobase Recognition by the ZTP Riboswitch. ACTA ACUST UNITED AC 2015; 22:829-37. [PMID: 26144884 DOI: 10.1016/j.chembiol.2015.06.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 05/30/2015] [Accepted: 06/02/2015] [Indexed: 01/14/2023]
Abstract
The ZTP riboswitch is a widespread family of regulatory RNAs that upregulate de novo purine synthesis in response to increased intracellular levels of ZTP or ZMP. As an important intermediate in purine biosynthesis, ZMP also serves as a proxy for the concentration of N10-formyl-tetrahydrofolate, a key component of one-carbon metabolism. Here, we report the structure of the ZTP riboswitch bound to ZMP at a resolution of 1.80 Å. The RNA contains two subdomains brought together through a long-range pseudoknot further stabilized through helix-helix packing. ZMP is bound at the subdomain interface of the RNA through a set of interactions with the base, ribose sugar, and phosphate moieties of the ligand. Unique to nucleobase recognition by RNAs, the Z base is inner-sphere coordinated to a magnesium cation bound by two backbone phosphates. This interaction, along with steric hindrance by the backbone, imparts specificity over chemically similar compounds such as ATP/AMP.
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Affiliation(s)
- Jeremiah J Trausch
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
| | - Joan G Marcano-Velázquez
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
| | - Michal M Matyjasik
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
| | - Robert T Batey
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA.
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134
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Liu Y, Holmstrom E, Zhang J, Yu P, Wang J, Dyba MA, Chen D, Ying J, Lockett S, Nesbitt DJ, Ferré-D'Amaré AR, Sousa R, Stagno JR, Wang YX. Synthesis and applications of RNAs with position-selective labelling and mosaic composition. Nature 2015; 522:368-72. [PMID: 25938715 PMCID: PMC4800989 DOI: 10.1038/nature14352] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 02/25/2015] [Indexed: 12/13/2022]
Abstract
Knowledge of the structure and dynamics of RNA molecules is critical to understanding their many biological functions. Furthermore, synthetic RNAs have applications as therapeutics and molecular sensors. Both research and technological applications of RNA would be dramatically enhanced by methods that enable incorporation of modified or labelled nucleotides into specifically designated positions or regions of RNA. However, the synthesis of tens of milligrams of such RNAs using existing methods has been impossible. Here we develop a hybrid solid-liquid phase transcription method and automated robotic platform for the synthesis of RNAs with position-selective labelling. We demonstrate its use by successfully preparing various isotope- or fluorescently labelled versions of the 71-nucleotide aptamer domain of an adenine riboswitch for nuclear magnetic resonance spectroscopy or single-molecule Förster resonance energy transfer, respectively. Those RNAs include molecules that were selectively isotope-labelled in specific loops, linkers, a helix, several discrete positions, or a single internal position, as well as RNA molecules that were fluorescently labelled in and near kissing loops. These selectively labelled RNAs have the same fold as those transcribed using conventional methods, but they greatly simplify the interpretation of NMR spectra. The single-position isotope- and fluorescently labelled RNA samples reveal multiple conformational states of the adenine riboswitch. Lastly, we describe a robotic platform and the operation that automates this technology. Our selective labelling method may be useful for studying RNA structure and dynamics and for making RNA sensors for a variety of applications including cell-biological studies, substance detection, and disease diagnostics.
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Affiliation(s)
- Yu Liu
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
| | - Erik Holmstrom
- JILA, National Institute of Standards and Technology and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Jinwei Zhang
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, Maryland 20892, USA
| | - Ping Yu
- Structural Biophysics Laboratory, Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, USA
| | - Jinbu Wang
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
| | - Marzena A Dyba
- Structural Biophysics Laboratory, Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, USA
| | - De Chen
- Optical Microscopy and Analysis Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Stephen Lockett
- Optical Microscopy and Analysis Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, USA
| | - David J Nesbitt
- JILA, National Institute of Standards and Technology and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, Maryland 20892, USA
| | - Rui Sousa
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Jason R Stagno
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
| | - Yun-Xing Wang
- Protein-Nucleic Acid Interaction Section, Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA
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135
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Abstract
Transfer RNA (tRNA) molecules contain many chemical modifications that are introduced after transcription. A major form of these modifications is methyl transfer to bases and backbone groups, using S-adenosyl methionine (AdoMet) as the methyl donor. Each methylation confers a specific advantage to tRNA in structure or in function. A remarkable methylation is to the G37 base on the 3'-side of the anticodon to generate m(1)G37-tRNA, which suppresses frameshift errors during protein synthesis and is therefore essential for cell growth in all three domains of life. This methylation is catalyzed by TrmD in bacteria and by Trm5 in eukaryotes and archaea. Although TrmD and Trm5 catalyze the same methylation reaction, kinetic analysis reveals that these two enzymes are unrelated to each other and are distinct in their reaction mechanism. This chapter summarizes the kinetic assays that are used to reveal the distinction between TrmD and Trm5. Three types of assays are described, the steady-state, the pre-steady-state, and the single-turnover assays, which collectively provide the basis for mechanistic investigation of AdoMet-dependent methyl transfer reactions.
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Affiliation(s)
- Ya-Ming Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania USA.
| | - Isao Masuda
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania USA
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136
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Liu G, Park HS, Pyo HM, Liu Q, Zhou Y. Influenza A Virus Panhandle Structure Is Directly Involved in RIG-I Activation and Interferon Induction. J Virol 2015; 89:6067-79. [PMID: 25810557 PMCID: PMC4442436 DOI: 10.1128/jvi.00232-15] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 03/21/2015] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED Retinoic acid-inducible gene I (RIG-I) is an important innate immune sensor that recognizes viral RNA in the cytoplasm. Its nonself recognition largely depends on the unique RNA structures imposed by viral RNA. The panhandle structure residing in the influenza A virus (IAV) genome, whose primary function is to serve as the viral promoter for transcription and replication, has been proposed to be a RIG-I agonist. However, this has never been proved experimentally. Here, we employed multiple approaches to determine if the IAV panhandle structure is directly involved in RIG-I activation and type I interferon (IFN) induction. First, in porcine alveolar macrophages, we demonstrated that the viral genomic coding region is dispensable for RIG-I-dependent IFN induction. Second, using in vitro-synthesized hairpin RNA, we showed that the IAV panhandle structure could directly bind to RIG-I and stimulate IFN production. Furthermore, we investigated the contributions of the wobble base pairs, mismatch, and unpaired nucleotides within the wild-type panhandle structure to RIG-I activation. Elimination of these destabilizing elements within the panhandle structure promoted RIG-I activation and IFN induction. Given the function of the panhandle structure as the viral promoter, we further monitored the promoter activity of these panhandle variants and found that viral replication was moderately affected, whereas viral transcription was impaired dramatically. In all, our results indicate that the IAV panhandle promoter region adopts a nucleotide composition that is optimal for balanced viral RNA synthesis and suboptimal for RIG-I activation. IMPORTANCE The IAV genomic panhandle structure has been proposed to be an RIG-I agonist due to its partial complementarity; however, this has not been experimentally confirmed. Here, we provide direct evidence that the IAV panhandle structure is competent in, and sufficient for, RIG-I activation and IFN induction. By constructing panhandle variants with increased complementarity, we demonstrated that the wild-type panhandle structure could be modified to enhance RIG-I activation and IFN induction. These panhandle variants posed moderate influence on viral replication but dramatic impairment of viral transcription. These results indicate that the IAV panhandle promoter region adopts a nucleotide composition to achieve optimal balance of viral RNA synthesis and suboptimal RIG-I activation. Our results highlight the multifunctional role of the IAV panhandle promoter region in the virus life cycle and offer novel insights into the development of antiviral agents aiming to boost RIG-I signaling or virus attenuation by manipulating this conserved region.
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Affiliation(s)
- GuanQun Liu
- Vaccine and Infectious Disease Organization-International Vaccine Center, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Hong-Su Park
- Vaccine and Infectious Disease Organization-International Vaccine Center, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Hyun-Mi Pyo
- Vaccine and Infectious Disease Organization-International Vaccine Center, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Qiang Liu
- Vaccine and Infectious Disease Organization-International Vaccine Center, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Yan Zhou
- Vaccine and Infectious Disease Organization-International Vaccine Center, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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137
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Anosova I, Melnik S, Tripsianes K, Kateb F, Grummt I, Sattler M. A novel RNA binding surface of the TAM domain of TIP5/BAZ2A mediates epigenetic regulation of rRNA genes. Nucleic Acids Res 2015; 43:5208-20. [PMID: 25916849 PMCID: PMC4446428 DOI: 10.1093/nar/gkv365] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 04/03/2015] [Indexed: 12/11/2022] Open
Abstract
The chromatin remodeling complex NoRC, comprising the subunits SNF2h and TIP5/BAZ2A, mediates heterochromatin formation at major clusters of repetitive elements, including rRNA genes, centromeres and telomeres. Association with chromatin requires the interaction of the TAM (TIP5/ARBP/MBD) domain of TIP5 with noncoding RNA, which targets NoRC to specific genomic loci. Here, we show that the NMR structure of the TAM domain of TIP5 resembles the fold of the MBD domain, found in methyl-CpG binding proteins. However, the TAM domain exhibits an extended MBD fold with unique C-terminal extensions that constitute a novel surface for RNA binding. Mutation of critical amino acids within this surface abolishes RNA binding in vitro and in vivo. Our results explain the distinct binding specificities of TAM and MBD domains to RNA and methylated DNA, respectively, and reveal structural features for the interaction of NoRC with non-coding RNA.
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Affiliation(s)
- Irina Anosova
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg D-85764, Germany Biomolecular NMR and Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München, Garching D-85747, Germany
| | - Svitlana Melnik
- Division of Molecular Biology of the Cell II, DKFZ-ZMBH Alliance, German Cancer Research Center, Heidelberg D-69120, Germany
| | - Konstantinos Tripsianes
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg D-85764, Germany Biomolecular NMR and Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München, Garching D-85747, Germany
| | - Fatiha Kateb
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg D-85764, Germany Biomolecular NMR and Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München, Garching D-85747, Germany
| | - Ingrid Grummt
- Division of Molecular Biology of the Cell II, DKFZ-ZMBH Alliance, German Cancer Research Center, Heidelberg D-69120, Germany
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg D-85764, Germany Biomolecular NMR and Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München, Garching D-85747, Germany
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138
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Leal NA, Kim HJ, Hoshika S, Kim MJ, Carrigan MA, Benner SA. Transcription, reverse transcription, and analysis of RNA containing artificial genetic components. ACS Synth Biol 2015; 4:407-13. [PMID: 25137127 DOI: 10.1021/sb500268n] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Expanding the synthetic biology of artificially expanded genetic information systems (AEGIS) requires tools to make and analyze RNA molecules having added nucleotide "letters". We report here the development of T7 RNA polymerase and reverse transcriptase to catalyze transcription and reverse transcription of xNA (DNA or RNA) having two complementary AEGIS nucleobases, 6-amino-5-nitropyridin-2-one (trivially, Z) and 2-aminoimidazo[1,2a]-1,3,5-triazin-4(8H)-one (trivially, P). We also report MALDI mass spectrometry and HPLC-based analyses for oligomeric GACUZP six-letter RNA and the use of ribonuclease (RNase) A and T1 RNase as enzymatic tools for the sequence-specific degradation of GACUZP RNA. We then applied these tools to analyze the GACUZP and GACTZP products of polymerases and reverse transcriptases (respectively) made from DNA and RNA templates. In addition to advancing this 6-letter AEGIS toward the biosynthesis of proteins containing additional amino acids, these experiments provided new insights into the biophysics of DNA.
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Affiliation(s)
- Nicole A. Leal
- Foundation
for
Applied Molecular Evolution (FfAME), 720 SW Second Avenue, Suite 201, Gainesville, Florida 32601, United States
- Firebird Biomolecular
Sciences LLC, 13709 Progress Boulevard, Box 17, Alachua, Florida 32615, United States
| | - Hyo-Joong Kim
- Foundation
for
Applied Molecular Evolution (FfAME), 720 SW Second Avenue, Suite 201, Gainesville, Florida 32601, United States
- Firebird Biomolecular
Sciences LLC, 13709 Progress Boulevard, Box 17, Alachua, Florida 32615, United States
| | - Shuichi Hoshika
- Foundation
for
Applied Molecular Evolution (FfAME), 720 SW Second Avenue, Suite 201, Gainesville, Florida 32601, United States
- Firebird Biomolecular
Sciences LLC, 13709 Progress Boulevard, Box 17, Alachua, Florida 32615, United States
| | - Myong-Jung Kim
- Foundation
for
Applied Molecular Evolution (FfAME), 720 SW Second Avenue, Suite 201, Gainesville, Florida 32601, United States
- Firebird Biomolecular
Sciences LLC, 13709 Progress Boulevard, Box 17, Alachua, Florida 32615, United States
| | - Matthew A. Carrigan
- Department
of Natural Sciences, Santa Fe College, 3000 NW 83rd Street L209, Gainesville, Florida 32606, United States
| | - Steven A. Benner
- Foundation
for
Applied Molecular Evolution (FfAME), 720 SW Second Avenue, Suite 201, Gainesville, Florida 32601, United States
- Firebird Biomolecular
Sciences LLC, 13709 Progress Boulevard, Box 17, Alachua, Florida 32615, United States
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139
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Rienzo M, Lummis SCR, Dougherty DA. Structural requirements in the transmembrane domain of GLIC revealed by incorporation of noncanonical histidine analogs. CHEMISTRY & BIOLOGY 2014; 21:1700-6. [PMID: 25525989 PMCID: PMC4291181 DOI: 10.1016/j.chembiol.2014.10.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/23/2014] [Accepted: 10/13/2014] [Indexed: 12/21/2022]
Abstract
The cyanobacterial pentameric ligand-gated ion channel GLIC, a homolog of the Cys-loop receptor superfamily, has provided useful structural and functional information about its eukaryotic counterparts. X-ray diffraction data and site-directed mutagenesis have previously implicated a transmembrane histidine residue (His234) as essential for channel function. Here, we investigated the role of His234 via synthesis and incorporation of histidine analogs and α-hydroxy acids using in vivo nonsense suppression. Receptors were expressed heterologously in Xenopus laevis oocytes, and whole-cell voltage-clamp electrophysiology was used to monitor channel activity. We show that an interhelix hydrogen bond involving His234 is important for stabilization of the open state, and that the shape and basicity of its side chain are highly sensitive to perturbations. In contrast, our data show that two other His residues are not involved in the acid-sensing mechanism.
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Affiliation(s)
- Matthew Rienzo
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sarah C R Lummis
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Dennis A Dougherty
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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140
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Jones CP, Ferré-D'Amaré AR. Crystal structure of a c-di-AMP riboswitch reveals an internally pseudo-dimeric RNA. EMBO J 2014; 33:2692-703. [PMID: 25271255 PMCID: PMC4282576 DOI: 10.15252/embj.201489209] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 01/13/2023] Open
Abstract
Cyclic diadenosine monophosphate (c-di-AMP) is a second messenger that is essential for growth and homeostasis in bacteria. A recently discovered c-di-AMP-responsive riboswitch controls the expression of genes in a variety of bacteria, including important pathogens. To elucidate the molecular basis for specific binding of c-di-AMP by a gene-regulatory mRNA domain, we have determined the co-crystal structure of this riboswitch. Unexpectedly, the structure reveals an internally pseudo-symmetric RNA in which two similar three-helix-junction elements associate head-to-tail, creating a trough that cradles two c-di-AMP molecules making quasi-equivalent contacts with the riboswitch. The riboswitch selectively binds c-di-AMP and discriminates exquisitely against other cyclic dinucleotides, such as c-di-GMP and cyclic-AMP-GMP, via interactions with both the backbone and bases of its cognate second messenger. Small-angle X-ray scattering experiments indicate that global folding of the riboswitch is induced by the two bound cyclic dinucleotides, which bridge the two symmetric three-helix domains. This structural reorganization likely couples c-di-AMP binding to gene expression.
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Affiliation(s)
- Christopher P Jones
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA
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141
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Daeffler KNM, Lester HA, Dougherty DA. Functional evaluation of key interactions evident in the structure of the eukaryotic Cys-loop receptor GluCl. ACS Chem Biol 2014; 9:2283-90. [PMID: 25051140 PMCID: PMC4201344 DOI: 10.1021/cb500323d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
The
publication of the first high-resolution crystal structure
of a eukaryotic Cys-loop receptor, GluClα, has provided valuable
structural information on this important class of ligand-gated ion
channels (LGIC). However, limited functional data exist for the GluCl
receptors. Before applying the structural insights from GluCl to mammalian
Cys-loop receptors such as nicotinic acetylcholine and GABA receptors,
it is important to ensure that established functional features of mammalian Cys-loop receptors are present in the more
distantly related GluCl receptors. Here, we seek to identify ligand-binding
interactions that are generally associated with Cys-loop receptors,
including the frequently observed cation−π interaction.
Our studies were performed on the highly homologous GluClβ receptor,
because GluClα is not activated by glutamate in Xenopus
laevis oocytes. Mutagenesis of the signal peptide and pore
lining helix was performed to enhance functional expression and sensitivity
to applied ligand, respectively. Conventional and unnatural amino
acid mutagenesis indicate a strong cation−π interaction
between Y206 and the protonated amine of glutamate, as well as other
important ionic and hydrogen bond interactions between the ligand
and the binding site, consistent with the crystal structure.
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Affiliation(s)
- Kristina N.-M. Daeffler
- Division of Chemistry & Chemical Engineering and ‡Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Henry A. Lester
- Division of Chemistry & Chemical Engineering and ‡Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Dennis A. Dougherty
- Division of Chemistry & Chemical Engineering and ‡Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, United States
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142
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Jiang T, Kennedy SD, Moss WN, Kierzek E, Turner DH. Secondary structure of a conserved domain in an intron of influenza A M1 mRNA. Biochemistry 2014; 53:5236-48. [PMID: 25026548 PMCID: PMC4139153 DOI: 10.1021/bi500611j] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Influenza A virus utilizes RNA throughout infection. Little is known, however, about the roles of RNA structures. A previous bioinformatics survey predicted multiple regions of influenza A virus that are likely to generate evolutionarily conserved and stable RNA structures. One predicted conserved structure is in the pre-mRNA coding for essential proteins, M1 and M2. This structure starts 79 nucleotides downstream of the M2 mRNA 5' splice site. Here, a combination of biochemical structural mapping, mutagenesis, and NMR confirms the predicted three-way multibranch structure of this RNA. Imino proton NMR spectra reveal no change in secondary structure when 80 mM KCl is supplemented with 4 mM MgCl2. Optical melting curves in 1 M NaCl and in 100 mM KCl with 10 mM MgCl2 are very similar, with melting temperatures ∼14 °C higher than that for 100 mM KCl alone. These results provide a firm basis for designing experiments and potential therapeutics to test for function in cell culture.
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Affiliation(s)
- Tian Jiang
- Department of Chemistry and Center for RNA Biology, University of Rochester , Rochester, New York 14627, United States
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143
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Lebars I, Vileno B, Bourbigot S, Turek P, Wolff P, Kieffer B. A fully enzymatic method for site-directed spin labeling of long RNA. Nucleic Acids Res 2014; 42:e117. [PMID: 24981512 PMCID: PMC4150755 DOI: 10.1093/nar/gku553] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Site-directed spin labeling is emerging as an essential tool to investigate the structural and dynamical features of RNA. We propose here an enzymatic method, which allows the insertion of a paramagnetic center at a specific position in an RNA molecule. The technique is based on a segmental approach using a ligation protocol with T4 RNA ligase 2. One transcribed acceptor RNA is ligated to a donor RNA in which a thio-modified nucleotide is introduced at its 5′-end by in vitro transcription with T7 RNA polymerase. The paramagnetic thiol-specific reagent is subsequently attached to the RNA ligation product. This novel strategy is demonstrated by introducing a paramagnetic probe into the 55 nucleotides long RNA corresponding to K-turn and Specifier Loop domains from the Bacillus subtilis tyrS T-Box leader RNA. The efficiency of the coupling reaction and the quality of the resulting spin-labeled RNA were assessed by Mass Spectrometry, Electron Paramagnetic Resonance (EPR) and Nuclear Magnetic Resonance (NMR). This method enables various combinations of isotopic segmental labeling and spin labeling schemes, a strategy that will be of particular interest to investigate the structural and dynamical properties of large RNA complexes by NMR and EPR spectroscopies.
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Affiliation(s)
- Isabelle Lebars
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Département de Biologie Structurale, Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé et de la Recherche Médicale (INSERM) U964/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, 67404 Illkirch cedex, France
| | - Bertrand Vileno
- Institut de Chimie, Laboratoire Propriétés Optiques & Magnétiques des Architectures Moléculaires, Université de Strasbourg, UMR 7177 CNRS, 4 rue Blaise Pascal, CS 90032, 67081 Strasbourg Cedex, France
| | - Sarah Bourbigot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Département de Biologie Structurale, Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé et de la Recherche Médicale (INSERM) U964/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, 67404 Illkirch cedex, France
| | - Philippe Turek
- Institut de Chimie, Laboratoire Propriétés Optiques & Magnétiques des Architectures Moléculaires, Université de Strasbourg, UMR 7177 CNRS, 4 rue Blaise Pascal, CS 90032, 67081 Strasbourg Cedex, France
| | - Philippe Wolff
- Institut de Biologie Moléculaire et Cellulaire, Plateforme Protéomique Strasbourg Esplanade, FRC 1589 CNRS, 15 rue René Descartes, 67084 Strasbourg Cedex, France Institut de Biologie Moléculaire et Cellulaire, Architecture et Réactivité des ARN, Université de Strasbourg, UPR 9002 CNRS, 15 rue René Descartes, 67084 Strasbourg Cedex, France
| | - Bruno Kieffer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Département de Biologie Structurale, Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé et de la Recherche Médicale (INSERM) U964/Université de Strasbourg, 1 rue Laurent Fries, BP 10142, 67404 Illkirch cedex, France
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144
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Terasaka N, Hayashi G, Katoh T, Suga H. An orthogonal ribosome-tRNA pair via engineering of the peptidyl transferase center. Nat Chem Biol 2014; 10:555-7. [PMID: 24907900 DOI: 10.1038/nchembio.1549] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 05/05/2014] [Indexed: 11/09/2022]
Abstract
The Watson-Crick base pairs between the 3'-terminal end of tRNAs and ribosomal RNA in the peptidyl transferase center are universally conserved. Here, we report that the introduction of compensatory mutations to Escherichia coli RNAs in this site leads to an orthogonal system independent of the wild-type counterpart, as demonstrated via the production of two peptide sequences from a single mRNA. This work thus identifies a new way to reprogram the genetic code.
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Affiliation(s)
- Naohiro Terasaka
- 1] Department of Chemistry, Graduate School of Science, University of Tokyo, Tokyo, Japan. [2]
| | - Gosuke Hayashi
- 1] Department of Chemistry, Graduate School of Science, University of Tokyo, Tokyo, Japan. [2] [3]
| | - Takayuki Katoh
- Department of Chemistry, Graduate School of Science, University of Tokyo, Tokyo, Japan
| | - Hiroaki Suga
- 1] Department of Chemistry, Graduate School of Science, University of Tokyo, Tokyo, Japan. [2] Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, University of Tokyo, Tokyo, Japan
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145
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Abstract
In recent years RNA molecules have emerged as central players in the regulation of gene expression. Many of these noncoding RNAs possess well-defined, complex, three-dimensional structures which are essential for their biological function. In this context, much effort has been devoted to develop computational and experimental techniques for RNA structure determination. Among available experimental tools to investigate the higher-order folding of structured RNAs, hydroxyl radical probing stands as one of the most informative and reliable ones. Hydroxyl radicals are oxidative species that cleave the nucleic acid backbone solely according to the solvent accessibility of individual phosphodiester bonds, with no sequence or secondary structure specificity. Therefore, the cleavage pattern obtained directly reflects the degree of protection/exposure to the solvent of each section of the molecule under inspection, providing valuable information about how these different sections interact together to form the final three-dimensional architecture. In this chapter we describe a robust, accurate and very sensitive hydroxyl radical probing method that can be applied to any structured RNA molecule and is suitable to investigate RNA folding and RNA conformational changes induced by binding of a ligand.
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146
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Abstract
Biotinylation of RNA allows its tight coupling to streptavidin and is thus useful for many types of experiments, e.g., pull-downs. Here we describe three simple techniques for biotinylating the 3' ends of RNA molecules generated by chemical or enzymatic synthesis. First, extension with either the Schizosaccharomyces pombe noncanonical poly(A) polymerase Cid1 or Escherichia coli poly(A) polymerase and N6-biotin-ATP is simple, efficient, and generally applicable independently of the 3'-end sequences of the RNA molecule to be labeled. However, depending on the enzyme and the reaction conditions, several or many biotinylated nucleotides are incorporated. Second, conditions are reported under which splint-dependent ligation by T4 DNA ligase can be used to join biotinylated and, presumably, other chemically modified DNA oligonucleotides to RNA 3' ends even if these are heterogeneous as is typical for products of enzymatic synthesis. Third, we describe the use of 29 DNA polymerase for a template-directed fill-in reaction that uses biotin-dUTP and, thanks to the enzyme's proofreading activity, can cope with more extended 3' heterogeneities.
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147
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Advances in methods for native expression and purification of RNA for structural studies. Curr Opin Struct Biol 2014; 26:1-8. [PMID: 24607442 DOI: 10.1016/j.sbi.2014.01.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/22/2014] [Accepted: 01/28/2014] [Indexed: 11/23/2022]
Abstract
Many RNAs present unique challenges in obtaining material suitable for structural or biophysical characterization. These issues include synthesis of chemically and conformationally homogeneous RNAs, refolding RNA purified using denaturing preparation techniques, and avoiding chemical damage. To address these challenges, new methodologies in RNA expression and purification have been developed seeking to emulate those commonly used for proteins. In this review, recent developments in the preparation of high-quality RNA for structural biology and biophysical applications are discussed, with an emphasis on native methods.
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148
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Abstract
RNAs play pivotal roles in the cell, ranging from catalysis (e.g., RNase P), acting as adaptor molecule (tRNA) to regulation (e.g., riboswitches). Precise understanding of its three-dimensional structures has given unprecedented insight into the molecular basis for all of these processes. Nevertheless, structural studies on RNA are still limited by the very special nature of this polymer. The most common methods for the determination of 3D RNA structures are NMR and X-ray crystallography. Both methods have their own set of requirements and give different amounts of information about the target RNA. For structural studies, the major bottleneck is usually obtaining large amounts of highly pure and homogeneously folded RNA. Especially for X-ray crystallography it can be necessary to screen a large number of variants to obtain well-ordered single crystals. In this mini-review we give an overview about strategies for the design, in vitro production, and purification of RNA for structural studies.
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Affiliation(s)
- Yasar Luqman Ahmed
- Department of Molecular Structural Biology; Institute for Microbiology and Genetics; Georg-August University; Göttingen, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology; Institute for Microbiology and Genetics; Georg-August University; Göttingen, Germany
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149
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McKay DB, Xi L, Barthel KKB, Cech TR. Structure and function of steroid receptor RNA activator protein, the proposed partner of SRA noncoding RNA. J Mol Biol 2014; 426:1766-1785. [PMID: 24486609 DOI: 10.1016/j.jmb.2014.01.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/21/2014] [Accepted: 01/22/2014] [Indexed: 11/28/2022]
Abstract
In a widely accepted model, the steroid receptor RNA activator protein (SRA protein; SRAP) modulates the transcriptional regulatory activity of SRA RNA by binding a specific stem-loop of SRA. We first confirmed that SRAP is present in the nucleus as well as the cytoplasm of MCF-7 breast cancer cells, where it is expressed at the level of about 10(5) molecules per cell. However, our SRAP-RNA binding experiments, both in vitro with recombinant protein and in cultured cells with plasmid-expressed protein and RNA, did not reveal a specific interaction between SRAP and SRA. We determined the crystal structure of the carboxy-terminal domain of human SRAP and found that it does not have the postulated RRM (RNA recognition motif). The structure is a five-helix bundle that is distinct from known RNA-binding motifs and instead is similar to the carboxy-terminal domain of the yeast spliceosome protein PRP18, which stabilizes specific protein-protein interactions within a multisubunit mRNA splicing complex. SRA binding experiments with this domain gave negative results. Transcriptional regulation by SRA/SRAP was examined with siRNA knockdown. Effects on both specific estrogen-responsive genes and genes identified by RNA-seq as candidates for regulation were examined in MCF-7 cells. Only a small effect (~20% change) on one gene resulting from depletion of SRA/SRAP could be confirmed. We conclude that the current model for SRAP function must be reevaluated; we suggest that SRAP may function in a different context to stabilize specific intermolecular interactions in the nucleus.
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Affiliation(s)
- David B McKay
- BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA.,Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA.,Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
| | - Linghe Xi
- BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Kristen K B Barthel
- BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Thomas R Cech
- BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA.,Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.,Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA
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150
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Anderson EG, Hoskins AA. Single molecule approaches for studying spliceosome assembly and catalysis. Methods Mol Biol 2014; 1126:217-41. [PMID: 24549668 DOI: 10.1007/978-1-62703-980-2_17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Single molecule assays of splicing and spliceosome assembly can provide unique insights into pre-mRNA processing that complement other technologies. Key to these experiments is the fabrication of fluorescent molecules (pre-mRNAs and spliceosome components) and passivated glass slides for each experiment. Here we describe how to produce fluorescent RNAs by splinted RNA ligation and fluorescent spliceosome subunits by SNAP-tagging proteins in cell lysate. We then depict how to passivate glass slides with polyethylene glycol for use on an inverted microscope with objective-based total internal reflection fluorescence (TIRF) optics. Finally, we describe how to tether the pre-mRNA onto the passivated slide surface and introduce the SNAP-tagged cell lysate for analysis of spliceosome assembly by single molecule fluorescence.
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Affiliation(s)
- Eric G Anderson
- Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
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